# Patent

## Title
Equipment protecting enclosures

## Abstract

Biomass (e.g., plant biomass, animal biomass, and municipal waste biomass) is processed to produce useful intermediates and products, such as energy, fuels, foods or materials. For example, systems and methods are described that can be used to treat feedstock materials, such as cellulosic and/or lignocellulosic materials, in a vault in which the equipment is protected from radiation and hazardous gases by equipment enclosures. The equipment enclosures may be purged with gas.

## Background
This application is a continuation application of U.S. patent application Ser. No. 15/136,343, filed Apr. 22, 2016, which is a continuation application of U.S. patent application Ser. No. 14/434,953, filed Apr. 10, 2015, now abandoned, which is a National Stage of International Application No. PCT/US2013/064317, filed Oct. 10, 2013, which claims the benefit of U.S. Provisional Application Nos. 61/711,801, filed on Oct. 10, 2012; 61/711,807, filed on Oct. 10, 2012; 61/774,684, filed on Mar. 8, 2013; 61/774,773, filed on Mar. 8, 2013; 61/774,731, filed on Mar. 8, 2013; 61/774,735, filed on Mar. 8, 2013; 61/774,740, filed on Mar. 8, 2013; 61/774,744, filed on Mar. 8, 2013; 61/774,746, filed on Mar. 8, 2013; 61/774,750, filed on Mar. 8, 2013; 61/774,752, filed on Mar. 8, 2013; 61/774,754, filed on Mar. 8, 2013; 61/774,775, filed on Mar. 8, 2013; 61/774,780, filed on Mar. 8, 2013; 61/774,761, filed on Mar. 8, 2013; 61/774,723, filed on Mar. 8, 2013; and 61/793,336, filed on Mar. 15, 2013, all of which are hereby incorporated by reference in their entireties.


BACKGROUND OF THE INVENTION
Many potential lignocellulosic feedstocks are available today, including agricultural residues, woody biomass, municipal waste, oilseeds/cakes and seaweed, to name a few. At present, these materials are often under-utilized, being used, for example, as animal feed, biocompost materials, burned in a co-generation facility or even landfilled.
Lignocellulosic biomass includes crystalline cellulose fibrils embedded in a hemicellulose matrix, surrounded by lignin. This produces a compact matrix that is difficult to access by enzymes and other chemical, biochemical and/or biological processes. Cellulosic biomass materials (e.g., biomass material from which the lignin has been removed) is more accessible to enzymes and other conversion processes, but even so, naturally-occurring cellulosic materials often have low yields (relative to theoretical yields) when contacted with hydrolyzing enzymes. Lignocellulosic biomass is even more recalcitrant to enzyme attack. Furthermore, each type of lignocellulosic biomass has its own specific composition of cellulose, hemicellulose and lignin.
SUMMARY
This invention relates to systems, methods and processing equipment used for producing products from a material, e.g., a biomass material. Generally, the methods include treating a recalcitrant biomass with electron beams while conveying the material using one or more conveyors in a vault and then biochemically and chemically processing the reduced recalcitrance material to, for example, ethanol, xylitol and other products. Radiation in the vault can cause damage to processing equipment in the vault or the radiation can create reactive gases, e.g., ozone, which can also degrade processing equipment. This damage can present hazards due to equipment failure as well as incurring costs due to down time and necessary repairs. Mitigation of this damage can be accomplished by enclosing equipment and/or components of the processing equipment in equipment enclosures that are radiation opaque and that can be purged with a gas that is inert to the components and/or equipment.
In one aspect the invention relates to a method of protecting processing equipment, e. g., material (e. g. biomass), biomass processing equipment, and other ancillary equipment that can be required for irradiation of biomass. The processing equipment can include, for example, a vibratory conveyor for conveying a biomass material under an electron beam and the associated equipment required for the conveyor, especially that which facilitates moving the biomass. This includes the equipment that provides the vibration for the conveyor. The ancillary conveyor parts include all of the parts that are required for conveying and, optionally, the vibratory part of the conveyor. The methods include enclosing motor components of the vibratory conveyor in a substantially radiation opaque equipment enclosure (e.g., material including lead) while purging the equipment enclosure with a gas. The method can reduce the exposure of the motor to radiation as compared to the radiation exposure that would occur without the equipment enclosure. For example, the radiation exposure to the motors can be reduced by at least 10%, at least 20%, at least 30%, at least 50%, at least 70% or even more (e.g., at least 90%).
In some instances, the gas used in the methods can include, for example, air, oxygen reduced air, inert gases, nitrogen, argon, helium, carbon dioxide, and mixtures of these. Optionally, the gas in the equipment enclosure is exchanged at an exchange time of at least 10 minutes (e.g., once every 5 minutes, once every minute, once every 30 seconds).
In some instances, the method further includes moving the equipment enclosure, e.g., to access the motors, position the equipment enclosures and/or adjust the equipment enclosure. The equipment enclosure can be configured to be movable (e.g., mounted on wheels, rails, sliders). Optionally, the method includes providing a gap between the equipment enclosure and the vibratory conveyor to accommodate vibration of components of the vibratory conveyor during use and/or providing a path for air flow out of the equipment enclosures.
In some other instances, the method includes placing the biomass processing equipment inside a vault. For example, the method can include methods wherein the vibratory conveyor is disposed within a vault. In addition and optionally the method can include methods wherein the vault contains irradiating equipment. Optionally the gas, for example, used to purge the equipment enclosures, is provided from within the vault. For example, gas that is provided from within the vault can be filtered or treated prior to purging the equipment enclosures (e.g., to remove ozone and/or destroy ozone).
In another aspect the invention relates to a system for protecting a motor e. g. a motor of a vibratory conveyor. The system can include a vibratory conveyor having motor components mounted on a planar structure and a substantially radiation opaque equipment enclosure configured to be positioned over the motor. The open end of the equipment enclosure is dimensioned so as to provide a circumferential gap between the equipment enclosure and the planar structure when the equipment enclosure is in place. Optionally, the gap is maintained by fixing the equipment enclosure relative to the conveyor using a stop, a groove, a spacer and/or a fastener. The system can further include a conduit configured for flowing a purging gas into the equipment enclosure. Optionally, the system includes equipment for moving the equipment enclosure into and out of position over the components, for example, including wheels attached to the equipment enclosure, tracks for sliding the equipment enclosure, wheels disposed below the equipment enclosure (e.g., attached to the ground), sliders (e.g., slide rails), linear guides and combinations thereof. The motor components include the motor, support structures, conduits, piping, electrical components. This can include the equipment required to move the enclosures.
In yet another aspect, the invention relates to a method of protecting biomass processing equipment. The method includes conveying a material, such as a biomass material, e. g., a lignocellulosic material, through a radiation field, such as under an electron beam on a vibratory conveyor. The method further includes enclosing motor components e. g. motor components of the conveyor, such as a vibratory conveyor, in a substantially radiation opaque equipment enclosure. For additional protection, the equipment enclosure can be purged with a gas, such as air, nitrogen or combinations of these.
The equipment enclosures described are effective in protecting processing equipment/components utilized in radiation processing of materials. The equipment enclosures also provide a volume within which the atmosphere can be easily controlled, e.g., exchanged or evacuated for ozone free air and/or other inert gases. The equipment enclosures can be easy to construct and durable presenting an economical solution to the incidental, accidental and or unintentional degradation of processing equipment due to radiation.
Implementations of the invention can optionally include one or more of the following summarized features. In some implementations, the selected features can be applied or utilized in any order while in others implementations a specific selected sequence is applied or utilized. Individual features can be applied or utilized more than once in any sequence. In addition, an entire sequence, or a portion of a sequence, of applied or utilized features can be applied or utilized once or repeatedly in any order. In some optional implementations, the features can be applied or utilized with different, or where applicable the same, set or varied, quantitative or qualitative parameters as determined by a person skilled in the art. For example, parameters of the features such as size, individual dimensions (e.g., length, width, height), location of, degree (e.g., to what extent such as the degree of recalcitrance), duration, frequency of use, density, concentration, intensity and speed can be varied or set, where applicable as determined by a person of skill in the art.
Features, for example, include a method for protecting material processing equipment, conveying a biomass material under an electron beam on a conveyor, and enclosing motor components of the conveyor in a radiation opaque equipment enclosure e.g., while purging the enclosure with a gas and where the gas can be air. The gas in the equipment enclosure is exchanged at a rate of less than once every 10 minutes. The gas used to purge the equipment enclosure may be air, oxygen reduced air, nitrogen, argon, helium, carbon dioxide, and mixtures thereof.
The conveyer for conveying the biomass is typically within a vault. The irradiating equipment can also be in the vault. The gas that is used to purge the equipment enclosure can come from within the vault and it can be filtered prior to using it in the equipment enclosure. The filtration of the gas may include removal of ozone. There is also a conduit configured for flowing the purging gas into the equipment enclosure. The conveyer can be a vibratory conveyor.
The equipment enclosure is movable such that there can be access to the motors such as the vibratory motors. The equipment enclosure and the conveyor are configured to accommodate movement of components when the conveyor is a vibratory conveyor and there can be a gap between the equipment enclosure and the vibratory conveyor equipment, especially the motor. The vibratory conveyor having motor components is mounted on a structure; such that when the equipment enclosure is in position to protect the motor equipment there is gap provided between structure and the equipment enclosure. This gap is maintained by fixing the equipment enclosure relative to the conveyor using a stop, groove, spacer or a fastener. In addition, equipment is provided to move the equipment enclosure into and out of positions over the conveyor components. The equipment to move the equipment enclosure may be wheels, tracks, slide rails, linear guides and combinations thereof.
The equipment enclosure can reduce the amount of radiation exposure the conveyer equipment gets by at least 10% when compared to no equipment enclosure. Alternately, the reduction of radiation exposure may be at least 20%, optionally at least 30%, or further optionally at least 50% and further at least 70% and alternatively at least 90% reduction in radiation exposure.
Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.



DESCRIPTION OF THE DRAWING
The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention.
FIG. 1 is a perspective cutout view of a vault showing enclosures for protecting components of biomass conveyors.
FIG. 2A is perspective view of a vibratory conveyor including equipment enclosures for protecting motor components of the conveyor. FIGS. 2B and 2C are detailed perspective views of an equipment enclosure.
FIG. 3A is a perspective view of a conduit. FIG. 3B is an axial cross-sectional view of the conduit. FIG. 3C is a radial cross-sectional view of the conduit taken along line 3C-3C in FIG. 3A.



DETAILED DESCRIPTION
Using the methods and systems described herein, cellulosic and lignocellulosic feedstock material, for example that can be sourced from biomass (e.g., plant biomass, animal biomass, paper, and municipal waste biomass) and that are often readily available but difficult to process, can be turned into useful products (e.g., sugars such as xylose and glucose, and alcohols such as ethanol and butanol). Included are methods and systems for treating biomass with radiation in which the processing equipment and/or components of the processing equipment are enclosed in radiation opaque equipment enclosures. In preferred implementations the equipment enclosures are purged with a gas that is inert to the components and/or equipment.
Many processes for manufacturing sugar solutions and products derived therefrom are described herein. These processes may include, for example, optionally mechanically treating a cellulosic and/or lignocellulosic feedstock. Before and/or after this treatment, the feedstock can be treated with another physical treatment, for example irradiation, steam explosion, pyrolysis, sonication and/or oxidation to reduce, or further reduce its recalcitrance. A sugar solution is formed by saccharifying the feedstock by, for example, the addition of one or more enzymes. A product can be derived from the sugar solution, for example, by fermentation to an alcohol. Further processing can include purifying the solution, for example by distillation. If desired, the steps of measuring lignin content and setting or adjusting process parameters (e.g., irradiation dosage) based on this measurement can be performed at various stages of the process, for example, as described in U.S. application Ser. No. 12/704,519, filed on Feb. 11, 2011, the complete disclosure of which is incorporated herein by reference.
Since the recalcitrance reducing treatment step can be a high energy process, the treatment can be performed in a vault and/or bunker to contain the energy and/or some of the products derived from the energetic process which can be hazardous. For example, the vault can be configured to contain heat energy, electrical energy (e.g., high voltages, electric discharges), radiation energy (e.g., X-rays, accelerated particles, gamma-rays, ultraviolet radiation), explosion energy (e.g., a shock wave, projectiles, blast wind), gases (e.g., ozone, steam, nitrogen oxides and/or volatile organic compounds) and combinations of these. Although this containment in a vault protects people and equipment outside of the vault, the equipment inside the vault is subjected to the energy and/or products derived from the energetic process. In some cases, this containment by the vault can exacerbate the effects, for example by not allowing dissipation of gases (e.g., ozone, steam, nitrogen oxides and/or volatile organic compounds), or by providing reflective surfaces for the radiation, or the vault can provide reflective surfaces for shock waves due to an explosion, or the enclosure can provide insulation causing the temperature in the vault to be elevated. The interior of the vault during operation can therefore be a damaging environment. Hazards to humans are mitigated by ensuring no-one is in the vault during operation. Hazards to the equipment can be mitigated by enclosing the equipment or components of the equipment in protective enclosures within the vault and/or bunker.
If treatment methods for reducing the recalcitrance include irradiation of the feedstock, for example, with ionizing radiation, unintentional irradiation of equipment within the vault can occur. For example, an electron beam striking a material can create X-rays through “breaking” radiation (Bremsstrahlung) that can also be ionizing depending on their energy. For example, irradiation of a biomass feedstock on a conveyor surface made of a metal (e.g., stainless steel) would create X-rays, especially when the electrons strike the metal surface. The production of X-rays when there is no biomass, or less than a sufficient amount of biomass to cover the conveyor surface, would be particularly strong, for example during a startup, shutdown or when the process is operating outside of its normal parameters.
In addition, electron beams can produce ozone by the irradiation of oxygen (e.g., oxygen present in air). Ozone is a strong oxidant with a redox potential of 2.07 V (vs. the Standard Hydrogen Electrode), higher than other known strong oxidants such as hydrogen peroxide, permanganate, chlorine gas and hypochlorite with redox potentials of 1.77V, 1.67V, 1.36V and 0.94V respectively. Therefore, materials, for example, organic materials, are susceptible to degradation by ionizing radiation and oxidation by ozone. For example, the materials can degrade through chain scission, cross-linking, oxidation and heating. In addition, metal components are susceptible to oxidation and degradation by ozone causing them, for example, to corrode/pit and/or rust.
Therefore, equipment that includes polymers and some metals (e.g., excluding perhaps corrosion resistant or noble metals) can be damaged. For example, damage can occur to belts that include organic material, for example those used in equipment, e.g., as the coupling between a drive motor and an eccentric fly wheel of a vibratory conveyor. (Vibratory conveyors are described in U.S. Provisional Application Ser. No. 61/711,807 filed Oct. 10, 2012, the entire disclosure therein described is herein by reference.) Systems and/or motor components that can be susceptible to damage by ozone and radiation include, for example, wheels, bearings, springs, shock absorbers, solenoids, actuators, switches, gears, axles, washers, adhesives, fasteners, bolts, nuts, screws, brackets, frames, pulleys, covers, vibration dampeners, sliders, filters, vents, pistons, fans, fan blades, wires, wire sheathing, valves, drive shafts, computer chips, microprocessors, circuit boards and cables. Some organic materials that can be degraded by ionizing radiation and ozone include thermoplastics and thermosets. For example, organic materials that can be susceptible to damage include phenolics (e.g., Bakelite), fluorinated hydrocarbons (e.g., Teflon), thermoplastics, polyamides, polyesters, polyurethanes, rubbers (e.g., butyl rubber, chlorinated polyethylene, polynorbornene), polyethers, polyethylene (Linear Low Density Polyethylene, High Density Polyethylene), polystyrenes, polyvinyls (e.g., Poly Vinyl Chloride), cellulosics, Amino resins (e.g., Urea Formaldehyde), polyamines, polyurethanes, polyamides, Acrylics (e.g., Methyl Methacrylate), Acetals (e.g., Polyoxymethylene) lubricants (e.g., oils and gels), polysiloxanes and combinations of these.
To protect equipment that can include the above discussed materials or other materials or equipment described herein, the invention includes enclosing and/or shielding the materials from the radiation using radiation opaque materials. In some implementations, the radiation opaque materials are selected to be capable of shielding the components from X-rays with high energy (short wavelength), which can penetrate many materials. One important factor in designing a radiation shielding enclosure is the attenuation length of the materials used, which will determine the required thickness for a particular material, blend of materials, or layered structure. The attenuation length is the penetration distance at which the radiation is reduced to approximately 1/e (e=Euler's number) times that of the incident radiation. Although virtually all materials are radiation opaque if thick enough, materials containing a high compositional percentage (e.g., density) of elements that have a high Z value (atomic number) have a shorter radiation attenuation length and thus if such materials are used a thinner, lighter enclosure can be provided. Examples of high Z value materials that are used in radiation shielding are tantalum and lead. Another important parameter in radiation shielding is the halving distance, which is the thickness of a particular material that will reduce gamma ray intensity by 50%. As an example for X-ray radiation with an energy of 0.1 MeV the halving thickness is about 15.1 mm for concrete and about 0.27 mm for lead, while with an X-ray energy of 1 MeV the halving thickness for concrete is about 44.45 mm and for lead is about 7.9 mm. Radiation opaque materials can be materials that are thick or thin so long as they can reduce the radiation that passes through to the other side. Thus, if it is desired that a particular enclosure have a low wall thickness, e.g., for light weight or due to size constraints, the material chosen should have a sufficient Z value and/or attenuation length so that its halving length is less than or equal to the desired wall thickness of the enclosure.
In some cases, the radiation opaque material may be a layered material, for example having a layer of a higher Z value material, to provide good shielding, and a layer of a lower Z value material to provide other properties (e.g., structural integrity, impact resistance, etc.). In some cases, the layered material may be a “graded-Z” laminate, e.g., including a laminate in which the layers provide a gradient from high-Z through successively lower-Z elements.
A radiation opaque material can reduce the radiation passing through a structure (e.g., a wall, door, ceiling, enclosure, a series of these or combinations of these) formed of the material by about at least about 10%, (e.g., at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99%, at least about 99.9%, at least about 99.99%, at least about 99.999%) as compared to the incident radiation. Therefore, an equipment enclosure made of a radiation opaque material can reduce the exposure of equipment/system/components by the same amount. Radiation opaque materials can include stainless steel, metals with Z values above 25 (e.g., lead, iron), concrete, dirt, sand and combinations thereof. Radiation opaque materials can include a barrier in the direction of the incident radiation of at least about 1 mm (e.g., 5 mm, 10 mm, 5 cm, 10 cm, 100 cm, 1 m, 10 m).
The materials chosen to be radiation opaque can be chosen, along with their radiation attenuation properties, based on their other functions. For example, the walls of a vault that may support a heavy ceiling and/or equipment and may seldom if ever need to be moved, can be constructed of concrete. A door to a vault would preferably be made relatively thin and light and easy to open and close (e.g., hinged or on a track) and may be made of layers including iron and lead. Preferably the enclosures for systems/equipment/components described herein would need to be relatively small and movable. For example, they should be movable by light equipment such as small fork lifts, motorized pulleys, or manually by a person. The weight should therefore be less than about 2000 kg (e.g., less than about 1000 kg, less than about 900 kg, less than about 800 kg, less than about 700 kg, less than about 600 kg, less than about 500 kg, less than about 400 kg, less than about 300 kg, less than about 200 kg, less than about 100 kg, less than about 50 kg, less than about 25 kg). The construction can include lead, stainless steel and other metals with Z numbers above 25. The enclosures can include layering of materials, for example lead and stainless steel, where lead can provide radiation protection while stainless steel can provide better structural properties.
In some cases the enclosures are mounted to be easily moved and/or removed. For example, the enclosures can be mounted and/or suspended on wheels (e.g., casters), rails, pulleys and/or hinges. The enclosures can also be partitioned where the partitions can be assembled or disassembled from around the equipment/system/component to be enclosed. Part of the enclosure can be integrated with the system/equipment/component to be enclosed. For example, the equipment may be mounted on a plate that is protective and configured to mate with the enclosure. The enclosures can be fastened to equipment, for example, by hooks, screws, bolts, straps, snaps, and/or other fasteners.
One or more enclosures can be used on a component, e.g., an inner enclosure surrounded by an outer (or several outer) enclosure(s). The enclosures can be of any shape and can include walls that are curved, flat, rough, smooth, spherical and/or angled. The enclosure can include tubes and ducts. The enclosures can be configured to be combined, for example to make a larger enclosure or to form different parts of an enclosure (e.g., a pipe can enclose part of the equipment, a box enclosing a second part of the equipment).
To protect equipment including metals and organics as discussed above from ozone, the enclosures for the equipment are configured to be purged by a flowing gas that is ozone free, or has less ozone than would be present during an irradiation process. This purging is particularly useful in cases where the enclosure cannot be readily sealed around the item to be protected, for example in the case of equipment that is moving and/or vibrating, such as the motor of a vibratory conveyor. In this case, the presence of the purge gas in the equipment enclosure excludes the entry of other gases (e.g., ozone) or particulates, which could otherwise enter the unsealed equipment enclosure. In some implementations, each enclosure has one or more inlets for allowing a purging gas to enter, and one or more outlets for the purging gas to exit. The purging gas can be sourced from outside of a vault that contains the irradiation equipment, and may be, for example atmospheric air, air from a tank, nitrogen, argon, helium or combinations of these. The purging gas can optionally be sourced from within the vault, although preferably if vault air is utilized, the air should be treated, for example filtered through an ozone reducing filter (e.g., including a carbon filter). The flow of air should be sufficient to keep any ozone that is present outside of the enclosure from entering the enclosure. For example, the exchange rate in the enclosure (the time it takes for the volume of air entering and exiting the enclosure to equal the total volume of the enclosure) is, for example, less than about 10 min (e.g., less than 9 min, less than 8 min, less than about 7 min, less than about 6 min, less than about 5 min, less than about 4 min, less than about 3 min, less than about 2 min, less than about 1 min, less than about 30 seconds, less than about 10 seconds, less than about 1 second). Alternatively or additionally, pressure in the interior of the enclosure can be slightly higher than the exterior, for example, by at least about 0.0001% (e.g., at least about 0.001%, at least about 0.01%, at least about 0.1%, at least about 1%, at least about 10%, at least about 50%, at least about 100%). Alternatively or additionally the average flux of the purging gas at the outlet(s) of the enclosure is at least 0.1 mLcm-2 sec-1 (e.g., at least about 0.5 mLcm-2 sec-1, at least about 1.0 mLcm-2 sec-1, at least about 2.0 mLcm-2 sec-1, at least about 5.0 mLcm-2 sec-1, at least about 10 mLcm-2 sec-1, at least about 20 mLcm-2 sec-1, at least about 30 mLcm-2 sec-1, at least about 40 mLcm-2 sec-1, at least about 50 mLcm-2 sec-1, at least about 60 mLcm-2 sec-1, at least about 70 mLcm-2 sec-1, at least about 80 mLcm-2 sec-1, at least about 90 mLcm-2 sec-1, at least about 100 mLcm-2 sec-1).
In some embodiments the purge gas can be a cooling gas, for example, the flow providing cooling to motor components. For example, the gas can be chilled prior to being sent into the enclosure or can be from a cooled source (e.g., liquid nitrogen blow off).
An embodiment of the invention is shown with reference to FIG. 1, which is a perspective view of a vault with enclosures protecting mechanical components of conveyors. The ceiling/roof is not shown in this view so that the interior of the vault can be more clearly seen. The boxes 112 and 114 are positioned next to a first conveyor 116. The boxes 122 and 124 are positioned next to a second conveyor 126. Conduits for electrical cables and/or gas (e.g., air, nitrogen) to the boxes are also shown as tubes 118, 120, 128 and 130 extending downwards from the ceiling. The tubes 118, 120, 128 and 130 pass through the ceiling. The boxes and conduits are constructed of radiation opaque materials, protecting the components inside the box (e.g., the motors and associated belts that drive the conveyors) from radiation and are both examples of enclosures for protecting equipment/systems and/or components.
In use, biomass is conveyed into the vault and onto the first conveyor trough drop opening 140 connected to the outside of the vault by a tube (not shown) passing through the ceiling. The biomass travels in the direction shown by the arrow and is dropped onto the second conveyor. The second conveyor coveys the biomass under the scanning horn 142. The scanning horn is connected to a high vacuum electron conduit 144, through the ceiling, and to an electron accelerator 146. The electron accelerator and power source 148 are supported by the roof of the vault. The atmosphere inside the vault contains elevated ozone levels due to the electron irradiation of atmospheric oxygen during the process. By purging the boxes through their respective conduits with a fluid that contains less ozone than that in the vault atmosphere, ozone in the vicinity of the mechanical components for the conveyors is reduced. The fluid can be, for example, atmospheric air, nitrogen, hydrogen, helium, vault air that has been treated to reduce the ozone level and mixtures of these. When the air that is used for purging the enclosures is vault air that has been treated to reduce ozone, the conduit for the purging gas need not be passed through the roof and can be part of a system including a pump and filter (e.g., an ozone filter) to remove the ozone laden air and pump out (into the enclosure) ozone free air.
FIG. 2A is a figure of a vibratory conveyor 116 with boxes 114 and 112 for covering mechanical components. The boxes are shown mounted on rails 212 and 214 through wheels, for example 222 and 224. The boxes can be moved on the rails in the directions indicted by the double headed arrow. In this view, the boxes are moved away from the conveyor, showing motor component 232. Conduit for electrical and/or gas purging are shown as 118 and 120 attached to the conveyor. When the conveyor is in operation, the boxes are pushed close to plates 250 and 251, enclosing the motor component. Preferably the edge 258 of the box is not in contact with the plate since the friction caused by the oscillation of the conveyor (and attached plate) against the edge of the box when the conveyor is in operation, would cause wear and heating. X-rays are shown in an arbitrary location to the X-rays which are formed when the electron beam strikes material, especially the surface of a metal such as a conveyor that does not have biomass on it. In addition, the gap between the box edge and plate provides a flow path out of the equipment enclosure so that the equipment enclosure can be purged. For example, an average gap between the edge and plate is preferably between 1 mm and 60 mm (e.g., between about 1-5 mm, 1-10 mm, 1-20 mm, 1-30 mm, 1-40 mm, 2-10 mm, 2-20 mm, 2-30 mm, 2-40 mm, 2-50 mm, 3-10 mm, 3-20 mm, 3-30 mm, 3-40 mm, 3-50 mm, 4-10 mm, 4-20 mm, 4-30 mm, 4-40 mm, 4-50 mm, 5-10 mm, 5-20 mm, 5-30 mm, 5-40 mm, 5-50 mm, 10-20 mm, 10-30 mm, 10-40 mm). The slots 252 and 254 accommodate the conduits 118 and 120 respectively so that the box and plate can form an equipment enclosure with only a minimal gap (e.g., similar to the gap between the plate and box edge) between the plates/conduits and boxes.
FIG. 2B is a close up view of box 114 in perspective showing the edge of the opening 258 for accepting vibratory conveyor components, e.g., a motor component. The rail 212 has stops 242 and 244 that can fix the box at a desired position on the rails.
FIG. 2C is another perspective view of the boxes. The box includes handles 262 and 264 that can be useful for gripping the boxes when they need to be moved.
In other embodiments, the gap between the equipment enclosure and the vibratory conveyor can be maintained by methods other than disclosed above. For example, the equipment enclosure could be set into a depression configured to accept the footprint of the equipment enclosure. Movable stops could be fixed by, for example friction or fasteners (e.g., pins, bolts), the floor and hold the equipment enclosures in position. The equipment enclosure could have casters that fit in a depression or set against stops. Magnetic stops can also be utilized. In some embodiments, the boxes could be suspended from the ceiling or a wall by structures (e.g., ridged structures, steel frames, beams, wall depressions, cables, combinations of these) in the desired position. The equipment enclosures could even be mounted on the vibrator while leaving the gap by using spacers as well as fasteners. In some instances, the equipment enclosures could be included as part of the conveyors, for example they could be covers for the motors that are made of radiation opaque materials and have an inlet and vents for purging with a gas.
FIG. 3A is a perspective view of a conduit 118 showing a cable 312 disposed therein. The can be an insulated electric cable for providing electrical power and signals to a motor. The cable could also include a mechanical cable, for example, for mechanically triggering a switch (e.g., emergency shut off). Although FIG. 3A shows only one cable, multiple cables and/or wires could be disposed in the conduit. FIGS. 3B and 3C are radial and axial cross-sectional views, respectively, of the conduit, showing the cable 312 in place within the internal cavity 314. The cable 312 runs through the conduit but does not fill the conduit so that a flow of gas through the conduit can be accommodated as shown by the arrows in FIG. 3B.
Radiation Treatment
The feedstock can be treated with electron bombardment to modify its structure to reduce its recalcitrance. Such treatment can, for example, reduce the average molecular weight of the feedstock, change the crystalline structure of the feedstock, and/or increase the surface area and/or porosity of the feedstock.
Electron bombardment via an electron beam is generally preferred, because it provides very high throughput. Electron beam accelerators are available, for example, from IBA, Belgium, and NHV Corporation, Japan.
Electron bombardment may be performed using an electron beam device that has a nominal energy of less than 10 MeV, e.g., less than 7 MeV, less than 5 MeV, or less than 2 MeV, e.g., from about 0.5 to 1.5 MeV, from about 0.8 to 1.8 MeV, or from about 0.7 to 1 MeV. In some implementations the nominal energy is about 500 to 800 keV.
The electron beam may have a relatively high total beam power (the combined beam power of all accelerating heads, or, if multiple accelerators are used, of all accelerators and all heads), e.g., at least 25 kW, e.g., at least 30, 40, 50, 60, 65, 70, 80, 100, 125, or 150 kW. In some cases, the power is even as high as 500 kW, 750 kW, or even 1000 kW or more. In some cases, the electron beam has a beam power of 1200 kW or more, e.g., 1400, 1600, 1800, or even 300 kW.
This high total beam power is usually achieved by utilizing multiple accelerating heads. For example, the electron beam device may include two, four, or more accelerating heads. The use of multiple heads, each of which has a relatively low beam power, prevents excessive temperature rise in the material, thereby preventing burning of the material, and also increases the uniformity of the dose through the thickness of the layer of material.
It is generally preferred that the bed of biomass material has a relatively uniform thickness. In some embodiments, the thickness is less than about 1 inch (e.g., less than about 0.75 inches, less than about 0.5 inches, less than about 0.25 inches, less than about 0.1 inches, between about 0.1 and 1 inch, between about 0.2 and 0.3 inches).
In some implementations, it is desirable to cool the material during and between dosing the material with electron bombardment. For example, the material can be cooled while it is conveyed, for example by a screw extruder, vibratory conveyor or other conveying equipment. For example, cooling while conveying is described in U.S. Provisional Application No. 61/774,735 and U.S. Provisional Application No. 61/774,752 the entire description therein is herein incorporated by reference.
To reduce the energy required by the recalcitrance-reducing process, it is desirable to treat the material as quickly as possible. In general, it is preferred that treatment be performed at a dose rate of greater than about 0.25 Mrad per second, e.g., greater than about 0.5, 0.75, 1, 1.5, 2, 5, 7, 10, 12, 15, or even greater than about 20 Mrad per second, e.g., about 0.25 to 2 Mrad per second. Higher dose rates allow a higher throughput for a target (e.g., the desired) dose. Higher dose rates generally require higher line speeds, to avoid thermal decomposition of the material. In one implementation, the accelerator is set for 3 MeV, 50 mA beam current, and the line speed is 24 feet/minute, for a sample thickness of about 20 mm (e.g., comminuted corn cob material with a bulk density of 0.5 g/cm3).
In some embodiments, electron bombardment is performed until the material receives a total dose of at least 0.1 Mrad, 0.25 Mrad, 1 Mrad, 5 Mrad, e.g., at least 10, 20, 30 or at least 40 Mrad. In some embodiments, the treatment is performed until the material receives a dose of from about 10 Mrad to about 50 Mrad, e.g., from about 20 Mrad to about 40 Mrad, or from about 25 Mrad to about 30 Mrad. In some implementations, a total dose of 25 to 35 Mrad is preferred, applied ideally over a couple of seconds, e.g., at 5 Mrad/pass with each pass being applied for about one second. Applying a dose of greater than 7 to 8 Mrad/pass can in some cases cause thermal degradation of the feedstock material. Cooling can be applied before, after, or during irradiation. For example, the cooling methods, systems and equipment as described in the following applications can be utilized: U.S. Provisional Application No. 61/774,735 and U.S. Provisional Application No. 61/774,754 the entire disclosures of which are herein incorporated by reference.
Using multiple heads as discussed above, the material can be treated in multiple passes, for example, two passes at 10 to 20 Mrad/pass, e.g., 12 to 18 Mrad/pass, separated by a few seconds of cool-down, or three passes of 7 to 12 Mrad/pass, e.g., 5 to 20 Mrad/pass, 10 to 40 Mrad/pass, 9 to 11 Mrad/pass. As discussed herein, treating the material with several relatively low doses, rather than one high dose, tends to prevent overheating of the material and also increases dose uniformity through the thickness of the material. In some implementations, the material is stirred or otherwise mixed during or after each pass and then smoothed into a uniform layer again before the next pass, to further enhance treatment uniformity.
In some embodiments, electrons are accelerated to, for example, a speed of greater than 75 percent of the speed of light, e.g., greater than 85, 90, 95, or 99 percent of the speed of light.
In some embodiments, any processing described herein occurs on lignocellulosic material that remains dry as acquired or that has been dried, e.g., using heat and/or reduced pressure. For example, in some embodiments, the cellulosic and/or lignocellulosic material has less than about 25 wt. % retained water, measured at 25° C. and at fifty percent relative humidity (e.g., less than about 20 wt. %, less than about 15 wt. %, less than about 14 wt. %, less than about 13 wt. %, less than about 12 wt. %, less than about 10 wt. %, less than about 9 wt. %, less than about 8 wt. %, less than about 7 wt. %, less than about 6 wt. %, less than about 5 wt. %, less than about 4 wt. %, less than about 3 wt. %, less than about 2 wt. %, less than about 1 wt. %, less than about 0.5 wt. %, less than about 15 wt. %.
In some embodiments, two or more electron sources are used, such as two or more ionizing sources. For example, samples can be treated, in any order, with a beam of electrons, followed by gamma radiation and UV light having wavelengths from about 100 nm to about 280 nm. In some embodiments, samples are treated with three ionizing radiation sources, such as a beam of electrons, gamma radiation, and energetic UV light. The biomass is conveyed through the treatment zone where it can be bombarded with electrons.
It may be advantageous to repeat the treatment to more thoroughly reduce the recalcitrance of the biomass and/or further modify the biomass. In particular the process parameters can be adjusted after a first (e.g., second, third, fourth or more) pass depending on the recalcitrance of the material. In some embodiments, a conveyor can be used which includes a recirculating system where the biomass is conveyed multiple times through the various processes described above. In some other embodiments, multiple treatment devices (e.g., electron beam generators) are used to treat the biomass multiple (e.g., 2, 3, 4 or more) times. In yet other embodiments, a single electron beam generator may be the source of multiple beams (e.g., 2, 3, 4 or more beams) that can be used for treatment of the biomass.
The effectiveness in changing the molecular/supermolecular structure and/or reducing the recalcitrance of the carbohydrate-containing biomass depends on the electron energy used and the dose applied, while exposure time depends on the power and dose. In some embodiments, the dose rate and total dose are adjusted so as not to destroy (e.g., char or burn) the biomass material. For example, the carbohydrates should not be damaged in the processing so that they can be released from the biomass intact, e.g. as monomeric sugars.
In some embodiments, the treatment (with any electron source or a combination of sources) is performed until the material receives a dose of at least about 0.05 Mrad, e.g., at least about 0.1, 0.25, 0.5, 0.75, 1.0, 2.5, 5.0, 7.5, 10.0, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, 125, 150, 175, or 200 Mrad. In some embodiments, the treatment is performed until the material receives a dose of between 0.1-100 Mrad, 1-200, 5-200, 10-200, 5-150, 50-150 Mrad, 5-100, 5-50, 5-40, 10-50, 10-75, 15-50, 20-35 Mrad.
In some embodiments, relatively low doses of radiation are utilized, e.g., to increase the molecular weight of a cellulosic or lignocellulosic material (with any radiation source or a combination of sources described herein). For example, a dose of at least about 0.05 Mrad, e.g., at least about 0.1 Mrad or at least about 0.25, 0.5, 0.75. 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, or at least about 5.0 Mrad. In some embodiments, the irradiation is performed until the material receives a dose of between 0.1 Mrad and 2.0 Mrad, e.g., between 0.5 rad and 4.0 Mrad or between 1.0 Mrad and 3.0 Mrad.
It also can be desirable to irradiate from multiple directions, simultaneously or sequentially, in order to achieve a desired degree of penetration of radiation into the material. For example, depending on the density and moisture content of the material, such as wood, and the type of radiation source used (e.g., gamma or electron beam), the maximum penetration of radiation into the material may be only about 0.75 inch. In such a cases, a thicker section (up to 1.5 inch) can be irradiated by first irradiating the material from one side, and then turning the material over and irradiating from the other side. Irradiation from multiple directions can be particularly useful with electron beam radiation, which irradiates faster than gamma radiation but typically does not achieve as great a penetration depth.
Radiation Opaque Materials
The invention can include processing the material in a vault and/or bunker that is constructed using radiation opaque materials. In some implementations, the radiation opaque materials are selected to be capable of shielding the components from X-rays with high energy (short wavelength), which can penetrate many materials. One important factor in designing a radiation shielding enclosure is the attenuation length of the materials used, which will determine the required thickness for a particular material, blend of materials, or layered structure. The attenuation length is the penetration distance at which the radiation is reduced to approximately 1/e (e=Euler's number) times that of the incident radiation. Although virtually all materials are radiation opaque if thick enough, materials containing a high compositional percentage (e.g., density) of elements that have a high Z value (atomic number) have a shorter radiation attenuation length and thus if such materials are used a thinner, lighter shielding can be provided. Examples of high Z value materials that are used in radiation shielding are tantalum and lead. Another important parameter in radiation shielding is the halving distance, which is the thickness of a particular material that will reduce gamma ray intensity by 50%. As an example for X-ray radiation with an energy of 0.1 MeV the halving thickness is about 15.1 mm for concrete and about 0.27 mm for lead, while with an X-ray energy of 1 MeV the halving thickness for concrete is about 44.45 mm and for lead is about 7.9 mm. Radiation opaque materials can be materials that are thick or thin so long as they can reduce the radiation that passes through to the other side. Thus, if it is desired that a particular enclosure have a low wall thickness, e.g., for light weight or due to size constraints, the material chosen should have a sufficient Z value and/or attenuation length so that its halving length is less than or equal to the desired wall thickness of the enclosure.
In some cases, the radiation opaque material may be a layered material, for example having a layer of a higher Z value material, to provide good shielding, and a layer of a lower Z value material to provide other properties (e.g., structural integrity, impact resistance, etc.). In some cases, the layered material may be a “graded-Z” laminate, e.g., including a laminate in which the layers provide a gradient from high-Z through successively lower-Z elements. In some cases, the radiation opaque materials can be interlocking blocks, for example, lead and/or concrete blocks can be supplied by NELCO Worldwide (Burlington, Mass.), and reconfigurable vaults can be utilized as described in U.S. Provisional Application No. 61/774,744.
A radiation opaque material can reduce the radiation passing through a structure (e.g., a wall, door, ceiling, enclosure, a series of these or combinations of these) formed of the material by about at least about 10%, (e.g., at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99%, at least about 99.9%, at least about 99.99%, at least about 99.999%) as compared to the incident radiation. Therefore, an enclosure made of a radiation opaque material can reduce the exposure of equipment/system/components by the same amount. Radiation opaque materials can include stainless steel, metals with Z values above 25 (e.g., lead, iron), concrete, dirt, sand and combinations thereof. Radiation opaque materials can include a barrier in the direction of the incident radiation of at least about 1 mm (e.g., 5 mm, 10 mm, 5 cm, 10 cm, 100 cm, 1 m, 10 m).
Radiation Sources
The type of radiation determines the kinds of radiation sources used as well as the radiation devices and associated equipment. The methods, systems and equipment described herein, for example for treating materials with radiation, can utilized sources as described herein as well as any other useful source.
Sources of gamma rays include radioactive nuclei, such as isotopes of cobalt, calcium, technicium, chromium, gallium, indium, iodine, iron, krypton, samarium, selenium, sodium, thalium, and xenon.
Sources of X-rays include electron beam collision with metal targets, such as tungsten or molybdenum or alloys, or compact light sources, such as those produced commercially by Lyncean.
Alpha particles are identical to the nucleus of a helium atom and are produced by the alpha decay of various radioactive nuclei, such as isotopes of bismuth, polonium, astatine, radon, francium, radium, several actinides, such as actinium, thorium, uranium, neptunium, curium, californium, americium, and plutonium.
Sources for ultraviolet radiation include deuterium or cadmium lamps.
Sources for infrared radiation include sapphire, zinc, or selenide window ceramic lamps.
Sources for microwaves include klystrons, Slevin type RF sources, or atom beam sources that employ hydrogen, oxygen, or nitrogen gases.
Accelerators used to accelerate the particles (e.g., electrons or ions) can be electrostatic DC, e. g. electrodynamic DC, RF linear, magnetic induction linear or continuous wave. For example, various irradiating devices may be used in the methods disclosed herein, including field ionization sources, electrostatic ion separators, field ionization generators, thermionic emission sources, microwave discharge ion sources, recirculating or static accelerators, dynamic linear accelerators, van de Graaff accelerators, Cockroft Walton accelerators (e.g., PELLETRON® accelerators), LINACS, Dynamitrons (e.g, DYNAMITRON® accelerators), cyclotrons, synchrotrons, betatrons, transformer-type accelerators, microtrons, plasma generators, cascade accelerators, and folded tandem accelerators. For example, cyclotron type accelerators are available from IBA, Belgium, such as the RHODOTRONTM system, while DC type accelerators are available from RDI, now IBA Industrial, such as the DYNAMITRON®. Other suitable accelerator systems include, for example: DC insulated core transformer (ICT) type systems, available from Nissin High Voltage, Japan; S-band LINACs, available from L3-PSD (USA), Linac Systems (France), Mevex (Canada), and Mitsubishi Heavy Industries (Japan); L-band LINACs, available from Iotron Industries (Canada); and ILU-based accelerators, available from Budker Laboratories (Russia). Ions and ion accelerators are discussed in Introductory Nuclear Physics, Kenneth S. Krane, John Wiley & Sons, Inc. (1988), Krsto Prelec, FIZIKA B 6 (1997) 4, 177-206, Chu, William T., “Overview of Light-Ion Beam Therapy”, Columbus-Ohio, ICRU-IAEA Meeting, 18-20 Mar. 2006, Iwata, Y. et al., “Alternating-Phase-Focused IH-DTL for Heavy-Ion Medical Accelerators”, Proceedings of EPAC 2006, Edinburgh, Scotland, and Leitner, C. M. et al., “Status of the Superconducting ECR Ion Source Venus”, Proceedings of EPAC 2000, Vienna, Austria. Some particle accelerators and their uses are disclosed, for example, in U.S. Pat. No. 7,931,784 to Medoff, the complete disclosure of which is incorporated herein by reference.
Electrons may be produced by radioactive nuclei that undergo beta decay, such as isotopes of iodine, cesium, technetium, and iridium. Alternatively, an electron gun can be used as an electron source via thermionic emission and accelerated through an accelerating potential. An electron gun generates electrons, which are then accelerated through a large potential (e.g., greater than about 500 thousand, greater than about lmillion, greater than about 2 million, greater than about 5 million, greater than about 6 million, greater than about 7 million, greater than about 8 million, greater than about 9 million, or even greater than 10 million volts) and then scanned magnetically in the x-y plane, where the electrons are initially accelerated in the z direction down the accelerator tube and extracted through a foil window. Scanning the electron beams is useful for increasing the irradiation surface when irradiating materials, e.g., a biomass, that is conveyed through the scanned beam. Scanning the electron beam also distributes the thermal load homogenously on the window and helps reduce the foil window rupture due to local heating by the electron beam. Window foil rupture is a cause of significant down-time due to subsequent necessary repairs and re-starting the electron gun.
A beam of electrons can be used as the radiation source. A beam of electrons has the advantages of high dose rates (e.g., 1, 5, or even 10 Mrad per second), high throughput, less containment, and less confinement equipment. Electron beams can also have high electrical efficiency (e.g., 80%), allowing for lower energy usage relative to other radiation methods, which can translate into a lower cost of operation and lower greenhouse gas emissions corresponding to the smaller amount of energy used. Electron beams can be generated, e.g., by electrostatic generators, cascade generators, transformer generators, low energy accelerators with a scanning system, low energy accelerators with a linear cathode, linear accelerators, and pulsed accelerators.
Electrons can also be more efficient at causing changes in the molecular structure of carbohydrate-containing materials, for example, by the mechanism of chain scission. In addition, electrons having energies of 0.5-10 MeV can penetrate low density materials, such as the biomass materials described herein, e.g., materials having a bulk density of less than 0.5 g/cm3, and a depth of 0.3-10 cm. Electrons as an ionizing radiation source can be useful, e.g., for relatively thin piles, layers or beds of materials, e.g., less than about 0.5 inch, e.g., less than about 0.4 inch, 0.3 inch, 0.25 inch, or less than about 0.1 inch. In some embodiments, the energy of each electron of the electron beam is from about 0.3 MeV to about 2.0 MeV (million electron volts), e.g., from about 0.5 MeV to about 1.5 MeV, or from about 0.7 MeV to about 1.25 MeV. Methods of irradiating materials are discussed in U.S. Pat. App. Pub. 2012/0100577 A1, filed Oct. 18, 2011, the entire disclosure of which is herein incorporated by reference.
Electron beam irradiation devices may be procured commercially or built. For example elements or components such inductors, capacitors, casings, power sources, cables, wiring, voltage control systems, current control elements, insulating material, microcontrollers and cooling equipment can be purchased and assembled into a device. Optionally, a commercial device can be modified and/or adapted. For example, devices and components can be purchased from any of the commercial sources described herein including Ion Beam Applications (Louvain-la-Neuve, Belgium), NHV Corporation (Japan), the Titan Corporation (San Diego, Calif.), Vivirad High Voltage Corp (Billeric, MA) and/or Budker Laboratories (Russia). Typical electron energies can be 0.5 MeV, 1 MeV, 2 MeV, 4.5 MeV, 7.5 MeV, or 10 MeV. Typical electron beam irradiation device power can be 1 kW, 5 kW, 10 kW, 20 kW, 50 kW, 60 kW, 70 kW, 80 kW, 90 kW, 100 kW, 125 kW, 150 kW, 175 kW, 200 kW, 250 kW, 300 kW, 350 kW, 400 kW, 450 kW, 500 kW, 600 kW, 700 kW, 800 kW, 900 kW or even 1000 kW. Accelerators that can be used include NHV irradiators medium energy series EPS-500 (e.g., 500 kV accelerator voltage and 65, 100 or 150 mA beam current), EPS-800 (e.g., 800 kV accelerator voltage and 65 or 100 mA beam current), or EPS-1000 (e.g., 1000 kV accelerator voltage and 65 or 100 mA beam current). Also, accelerators from NHV's high energy series can be used such as EPS-1500 (e.g., 1500 kV accelerator voltage and 65 mA beam current), EPS-2000 (e.g., 2000 kV accelerator voltage and 50 mA beam current), EPS-3000 (e.g., 3000 kV accelerator voltage and 50 mA beam current) and EPS-5000 (e.g., 5000 and 30 mA beam current).
Tradeoffs in considering electron beam irradiation device power specifications include cost to operate, capital costs, depreciation, and device footprint. Tradeoffs in considering exposure dose levels of electron beam irradiation would be energy costs and environment, safety, and health (ESH) concerns. Typically, generators are housed in a vault, e.g., of lead or concrete, especially for production from X-rays that are generated in the process. Tradeoffs in considering electron energies include energy costs.
The electron beam irradiation device can produce either a fixed beam or a scanning beam. A scanning beam may be advantageous with large scan sweep length and high scan speeds, as this would effectively replace a large, fixed beam width. Further, available sweep widths of 0.5 m, 1 m, 2 m or more are available. The scanning beam is preferred in most embodiments describe herein because of the larger scan width and reduced possibility of local heating and failure of the windows.
Electron Guns—Windows
The extraction system for an electron accelerator can include two window foils. Window foils are described in U.S. Provisional Application Ser. No. 61/711,801 filed Oct. 10, 2012 the complete disclosure of which is herein incorporated by reference. The cooling gas in the two foil window extraction system can be a purge gas or a mixture, for example air, or a pure gas. In one embodiment the gas is an inert gas such as nitrogen, argon, helium and or carbon dioxide. It is preferred to use a gas rather than a liquid since energy losses to the electron beam are minimized. Mixtures of pure gas can also be used, either pre-mixed or mixed in line prior to impinging on the windows or in the space between the windows. The cooling gas can be cooled, for example, by using a heat exchange system (e.g., a chiller) and/or by using boil off from a condensed gas (e.g., liquid nitrogen, liquid helium).
When using a conveyor enclosure, the enclosed conveyor can also be purged with an inert gas so as to maintain an atmosphere at a reduced oxygen level. Keeping oxygen levels low avoids the formation of ozone which in some instances is undesirable due to its reactive and toxic nature. For example, the oxygen can be less than about 20% (e.g., less than about 10%, less than about 1%, less than about 0.1%, less than about 0.01%, or even less than about 0.001% oxygen). Purging can be done with an inert gas including, but not limited to, nitrogen, argon, helium or carbon dioxide. This can be supplied, for example, from a boil off of a liquid source (e.g., liquid nitrogen or helium), generated or separated from air in situ, or supplied from tanks. The inert gas can be recirculated and any residual oxygen can be removed using a catalyst, such as a copper catalyst bed. Alternatively, combinations of purging, recirculating and oxygen removal can be done to keep the oxygen levels low.
The conveyor enclosure can also be purged with a reactive gas that can react with the biomass. This can be done before, during or after the irradiation process. The reactive gas can be, but is not limited to, nitrous oxide, ammonia, oxygen, ozone, hydrocarbons, aromatic compounds, amides, peroxides, azides, halides, oxyhalides, phosphides, phosphines, arsines, sulfides, thiols, boranes and/or hydrides. The reactive gas can be activated in the conveyor enclosure, e.g., by irradiation (e.g., electron beam, UV irradiation, microwave irradiation, heating, IR radiation), so that it reacts with the biomass. The biomass itself can be activated, for example by irradiation. Preferably the biomass is activated by the electron beam, to produce radicals which then react with the activated or unactivated reactive gas, e.g., by radical coupling or quenching.
Purging gases supplied to an enclosed conveyor can also be cooled, for example below about 25° C., below about 0° C., below about −40° C., below about −80° C., below about −120° C. For example, the gas can be boiled off from a compressed gas such as liquid nitrogen or sublimed from solid carbon dioxide. As an alternative example, the gas can be cooled by a chiller or part of or the entire conveyor can be cooled.
Heating and Throughput During Radiation Treatment
Several processes can occur in biomass when electrons from an electron beam interact with matter in inelastic collisions. For example, ionization of the material, chain scission of polymers in the material, cross linking of polymers in the material, oxidation of the material, generation of X-rays (“Bremsstrahlung”) and vibrational excitation of molecules (e.g. phonon generation). Without being bound to a particular mechanism, the reduction in recalcitrance can be due to several of these inelastic collision effects, for example ionization, chain scission of polymers, oxidation and phonon generation. Some of the effects (e.g., especially X-ray generation), necessitate shielding and engineering barriers, for example, enclosing the irradiation processes in a concrete (or other radiation opaque material) vault. Another effect of irradiation, vibrational excitation, is equivalent to heating up the sample. Heating the sample by irradiation can help in recalcitrance reduction, but excessive heating can destroy the material, as will be explained below.
The adiabatic temperature rise (ΔT) from adsorption of ionizing radiation is given by the equation: ΔT=D/Cp: where D is the average dose in kGy, Cp is the heat capacity in J/g ° C., and ΔT is the change in temperature in ° C. A typical dry biomass material will have a heat capacity close to 2. Wet biomass will have a higher heat capacity dependent on the amount of water since the heat capacity of water is very high (4.19 J/g ° C.). Metals have much lower heat capacities, for example 304 stainless steel has a heat capacity of 0.5 J/g ° C. The temperature change due to the instant adsorption of radiation in a biomass and stainless steel for various doses of radiation is shown in Table 1.







TABLE 1







Calculated Temperature increase for biomass and stainless steel.











Dose (Mrad)
Estimated Biomass ΔT (° C.)
Steel ΔT (° C.)















10
50
200



50
250
1000



100
500
2000



150
750
3000



200
1000
4000










High temperatures can destroy and or modify the biopolymers in biomass so that the polymers (e.g., cellulose) are unsuitable for further processing. A biomass subjected to high temperatures can become dark, sticky and give off odors indicating decomposition. The stickiness can even make the material hard to convey. The odors can be unpleasant and be a safety issue. In fact, keeping the biomass below about 200° C. has been found to be beneficial in the processes described herein (e.g., below about 190° C., below about 180° C., below about 170° C., below about 160° C., below about 150° C., below about 140° C., below about 130° C., below about 120° C., below about 110° C., between about 60° C. and 180° C., between about 60° C. and 160° C., between about 60° C. and 150° C., between about 60° C. and 140° C., between about 60° C. and 130° C., between about 60° C. and 120° C., between about 80° C. and 180° C., between about 100° C. and 180° C., between about 120° C. and 180° C., between about 140° C. and 180° C., between about 160° C. and 180° C., between about 100° C. and 140° C., between about 80° C. and 120° C.).
It has been found that irradiation above about 10 Mrad is desirable for the processes described herein (e.g., reduction of recalcitrance). A high throughput is also desirable so that the irradiation does not become a bottle neck in processing the biomass. The treatment is governed by a Dose rate equation: M=FP/D*time, where M is the mass of irradiated material (Kg), F is the fraction of power that is adsorbed (unit less), P is the emitted power (kW=Voltage in MeV*Current in mA), time is the treatment time (sec) and D is the adsorbed dose (kGy). In an exemplary process where the fraction of adsorbed power is fixed, the Power emitted is constant and a set dosage is desired, the throughput (e.g., M, the biomass processed) can be increased by increasing the irradiation time. However, increasing the irradiation time without allowing the material to cool, can excessively heat the material as exemplified by the calculations shown above. Since biomass has a low thermal conductivity (less than about 0.1 Wm−1K−1), heat dissipation is slow, unlike, for example metals (greater than about 10 Wm−1K−1) which can dissipate energy quickly as long as there is a heat sink to transfer the energy to.
Electron Guns—Beam Stops
In some embodiments the systems and methods include a beam stop (e.g., a shutter). For example, the beam stop can be used to quickly stop or reduce the irradiation of material without powering down the electron beam device. Alternatively, the beam stop can be used while powering up the electron beam, e.g., the beam stop can stop the electron beam until a beam current of a desired level is achieved. The beam stop can be placed between the primary foil window and secondary foil window. For example, the beam stop can be mounted so that it is movable, that is, so that it can be moved into and out of the beam path. Even partial coverage of the beam can be used, for example, to control the dose of irradiation. The beam stop can be mounted to the floor, to a conveyor for the biomass, to a wall, to the radiation device (e.g., at the scan horn), or to any structural support. Preferably the beam stop is fixed in relation to the scan horn so that the beam can be effectively controlled by the beam stop. The beam stop can incorporate a hinge, a rail, wheels, slots, or other means allowing for its operation in moving into and out of the beam. The beam stop can be made of any material that will stop at least 5% of the electrons, e.g., at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or even about 100% of the electrons.
The beam stop can be made of a metal including, but not limited to, stainless steel, lead, iron, molybdenum, silver, gold, titanium, aluminum, tin, or alloys of these, or laminates (layered materials) made with such metals (e.g., metal-coated ceramic, metal-coated polymer, metal-coated composite, multilayered metal materials).
The beam stop can be cooled, for example, with a cooling fluid such as an aqueous solution or a gas. The beam stop can be partially or completely hollow, for example with cavities. Interior spaces of the beam stop can be used for cooling fluids and gases. The beam stop can be of any shape, including flat, curved, round, oval, square, rectangular, beveled and wedged shapes.
The beam stop can have perforations so as to allow some electrons through, thus controlling (e.g., reducing) the levels of radiation across the whole area of the window, or in specific regions of the window. The beam stop can be a mesh formed, for example, from fibers or wires. Multiple beam stops can be used, together or independently, to control the irradiation. The beam stop can be remotely controlled, e.g., by radio signal or hard wired to a motor for moving the beam into or out of position.
Beam Dumps
The embodiments disclosed herein can also include a beam dump. A beam dump's purpose is to safely absorb a beam of charged particles. Like a beam stop, a beam dump can be used to block the beam of charged particles. However, a beam dump is much more robust than a beam stop, and is intended to block the full power of the electron beam for an extended period of time. They are often used to block the beam as the accelerator is powering up.
Beam dumps are also designed to accommodate the heat generated by such beams, and are usually made from materials such as copper, aluminum, carbon, beryllium, tungsten, or mercury. Beam dumps can be cooled, for example by using a cooling fluid that is in thermal contact with the beam dump.
Biomass Materials
Lignocellulosic materials include, but are not limited to, wood, particle board, forestry wastes (e.g., sawdust, aspen wood, wood chips), grasses, (e.g., switchgrass, miscanthus, cord grass, reed canary grass), grain residues, (e.g., rice hulls, oat hulls, wheat chaff, barley hulls), agricultural waste (e.g., silage, canola straw, wheat straw, barley straw, oat straw, rice straw, jute, hemp, flax, bamboo, sisal, abaca, corn cobs, corn stover, soybean stover, corn fiber, alfalfa, hay, coconut hair), sugar processing residues (e.g., bagasse, beet pulp, agave bagasse), algae, seaweed, manure, sewage, and mixtures of any of these.
In some cases, the lignocellulosic material includes corncobs. Ground or hammer milled corncobs can be spread in a layer of relatively uniform thickness for irradiation, and after irradiation are easy to disperse in the medium for further processing. To facilitate harvest and collection, in some cases the entire corn plant is used, including the corn stalk, corn kernels, and in some cases even the root system of the plant.
Advantageously, no additional nutrients (other than a nitrogen source, e.g., urea or ammonia) are required during fermentation of corncobs or cellulosic or lignocellulosic materials containing significant amounts of corncobs.
Corncobs, before and after comminution, are also easier to convey and disperse, and have a lesser tendency to form explosive mixtures in air than other cellulosic or lignocellulosic materials such as hay and grasses.
Cellulosic materials include, for example, paper, paper products, paper waste, paper pulp, pigmented papers, loaded papers, coated papers, filled papers, magazines, printed matter (e.g., books, catalogs, manuals, labels, calendars, greeting cards, brochures, prospectuses, newsprint), printer paper, polycoated paper, card stock, cardboard, paperboard, materials having a high α-cellulose content such as cotton, and mixtures of any of these. For example paper products as described in U.S. application Ser. No. 13/396,365 (“Magazine Feedstocks” by Medoff et al., filed Feb. 14, 2012), the full disclosure of which is incorporated herein by reference.
Cellulosic materials can also include lignocellulosic materials which have been partially or fully de-lignified.
In some instances other biomass materials can be utilized, for example starchy materials. Starchy materials include starch itself, e.g., corn starch, wheat starch, potato starch or rice starch, a derivative of starch, or a material that includes starch, such as an edible food product or a crop. For example, the starchy material can be arracacha, buckwheat, banana, barley, cassava, kudzu, oca, sago, sorghum, regular household potatoes, sweet potato, taro, yams, or one or more beans, such as favas, lentils or peas. Blends of any two or more starchy materials are also starchy materials. Mixtures of starchy, cellulosic and or lignocellulosic materials can also be used. For example, a biomass can be an entire plant, a part of a plant or different parts of a plant, e.g., a wheat plant, cotton plant, a corn plant, rice plant or a tree. The starchy materials can be treated by any of the methods described herein.
Microbial materials include, but are not limited to, any naturally occurring or genetically modified microorganism or organism that contains or is capable of providing a source of carbohydrates (e.g., cellulose), for example, protists, e.g., animal protists (e.g., protozoa such as flagellates, amoeboids, ciliates, and sporozoa) and plant protists (e.g., algae such alveolates, chlorarachniophytes, cryptomonads, euglenids, glaucophytes, haptophytes, red algae, stramenopiles, and viridaeplantae). Other examples include seaweed, plankton (e.g., macroplankton, mesoplankton, microplankton, nanoplankton, picoplankton, and fem
toplankton), phytoplankton, bacteria (e.g., gram positive bacteria, gram negative bacteria, and extremophiles), yeast and/or mixtures of these. In some instances, microbial biomass can be obtained from natural sources, e.g., the ocean, lakes, bodies of water, e.g., salt water or fresh water, or on land. Alternatively or in addition, microbial biomass can be obtained from culture systems, e.g., large scale dry and wet culture and fermentation systems.
In other embodiments, the biomass materials, such as cellulosic, starchy and lignocellulosic feedstock materials, can be obtained from transgenic microorganisms and plants that have been modified with respect to a wild type variety. Such modifications may be, for example, through the iterative steps of selection and breeding to obtain desired traits in a plant. Furthermore, the plants can have had genetic material removed, modified, silenced and/or added with respect to the wild type variety. For example, genetically modified plants can be produced by recombinant DNA methods, where genetic modifications include introducing or modifying specific genes from parental varieties, or, for example, by using transgenic breeding wherein a specific gene or genes are introduced to a plant from a different species of plant and/or bacteria. Another way to create genetic variation is through mutation breeding wherein new alleles are artificially created from endogenous genes. The artificial genes can be created by a variety of ways including treating the plant or seeds with, for example, chemical mutagens (e.g., using alkylating agents, epoxides, alkaloids, peroxides, formaldehyde), irradiation (e.g., X-rays, gamma rays, neutrons, beta particles, alpha particles, protons, deuterons, UV radiation) and temperature shocking or other external stressing and subsequent selection techniques. Other methods of providing modified genes is through error prone PCR and DNA shuffling followed by insertion of the desired modified DNA into the desired plant or seed. Methods of introducing the desired genetic variation in the seed or plant include, for example, the use of a bacterial carrier, biolistics, calcium phosphate precipitation, electroporation, gene splicing, gene silencing, lipofection, microinjection and viral carriers. Additional genetically modified materials have been described in U.S. application Ser. No. 13/396,369 filed Feb. 14, 2012 the full disclosure of which is incorporated herein by reference.
Any of the methods described herein can be practiced with mixtures of any biomass materials described herein.
Other Materials
Other materials (e.g., natural or synthetic materials), for example polymers, can be treated and/or made utilizing the methods, equipment and systems described herein. For example, polyethylene (e.g., linear low density ethylene and high density polyethylene), polystyrenes, sulfonated polystyrenes, poly (vinyl chloride), polyesters (e.g., nylons, DacronTM, KodelTM), polyalkylene esters, poly vinyl esters, polyamides (e.g., KevlarTM), polyethylene terephthalate, cellulose acetate, acetal, poly acrylonitrile, polycarbonates(LexanTM), acrylics [e.g., poly (methyl methacrylate), poly(methyl methacrylate), polyacrylnitriles, Polyurethanes, polypropylene, poly butadiene, polyisobutylene, polyacrylonitrile, polychloroprene (e.g. neoprene), poly(cis-1,4-isoprene) [e.g., natural rubber], poly(trans-1,4-isoprene) [e.g., gutta percha], phenol formaldehyde, melamine formaldehyde, epoxides, polyesters, poly amines, polycarboxylic acids, polylactic acids, polyvinyl alcohols, polyanhydrides, poly fluoro carbons (e.g., TeflonTM), silicons (e.g., silicone rubber), polysilanes, poly ethers (e.g., polyethylene oxide, polypropylene oxide), waxes, oils and mixtures of these. Also included are plastics, rubbers, elastomers, fibers, waxes, gels, oils, adhesives, thermoplastics, thermosets, biodegradable polymers, resins made with these polymers, other polymers, other materials and combinations thereof. The polymers can be made by any useful method including cationic polymerization, anionic polymerization, radical polymerization, metathesis polymerization, ring opening polymerization, graft polymerization, addition polymerization. In some cases the treatments disclosed herein can be used, for example, for radically initiated graft polymerization and cross linking. Composites of polymers, for example with glass, metals, biomass (e.g., fibers, particles), ceramics can also be treated and/or made.
Other materials that can be treated by using the methods, systems and equipment disclosed herein are ceramic materials, minerals, metals, inorganic compounds. For example, silicon and germanium crystals, silicon nitrides, metal oxides, semiconductors, insulators, cements and or conductors.
In addition, manufactured multipart or shaped materials (e.g., molded, extruded, welded, riveted, layered or combined in any way) can be treated, for example cables, pipes, boards, enclosures, integrated semiconductor chips, circuit boards, wires, tires, windows, laminated materials, gears, belts, machines, combinations of these. For example, treating a material by the methods described herein can modify the surfaces, for example, making them susceptible to further functionalization, combinations (e.g., welding) and/or treatment can cross link the materials.
Biomass Material Preparation—Mechanical Treatments
The biomass can be in a dry form, for example with less than about 35% moisture content (e.g., less than about 20%, less than about 15%, less than about 10% less than about 5%, less than about 4%, less than about 3%, less than about 2% or even less than about 1%). The biomass can also be delivered in a wet state, for example as a wet solid, a slurry or a suspension with at least about 10 wt. % solids (e.g., at least about 20 wt. %, at least about 30 wt. %, at least about 40 wt. %, at least about 50 wt. %, at least about 60 wt. %, at least about 70 wt. %).
The processes disclosed herein can utilize low bulk density materials, for example cellulosic or lignocellulosic feedstocks that have been physically pretreated to have a bulk density of less than about 0.75 g/cm3, e.g., less than about 0.7, 0.65, 0.60, 0.50, 0.35, 0.25, 0.20, 0.15, 0.10, 0.05 or less, e.g., less than about 0.025 g/cm3. Bulk density is determined using ASTM D1895B. Briefly, the method involves filling a measuring cylinder of known volume with a sample and obtaining a weight of the sample. The bulk density is calculated by dividing the weight of the sample in grams by the known volume of the cylinder in cubic centimeters. If desired, low bulk density materials can be densified, for example, by methods described in U.S. Pat. No. 7,971,809 to Medoff, the full disclosure of which is hereby incorporated by reference. In some cases, the pre-treatment processing includes screening of the biomass material. Screening can be through a mesh or perforated plate with a desired opening size, for example, less than about 6.35 mm (1⁄4 inch, 0.25 inch), (e.g., less than about 3.18 mm (1⁄8 inch, 0.125 inch), less than about 1.59 mm ( 1/16 inch, 0.0625 inch), is less than about 0.79 mm ( 1/32 inch, 0.03125 inch), e.g., less than about 0.51 mm ( 1/50 inch, 0.02000 inch), less than about 0.40 mm ( 1/64 inch, 0.015625 inch), less than about 0.23 mm (0.009 inch), less than about 0.20 mm ( 1/128 inch, 0.0078125 inch), less than about 0.18 mm (0.007 inch), less than about 0.13 mm (0.005 inch), or even less than about 0.10 mm ( 1/256 inch, 0.00390625 inch)). In one configuration the desired biomass falls through the perforations or screen and thus biomass larger than the perforations or screen are not irradiated. These larger materials can be re-processed, for example by comminuting, or they can simply be removed from processing. In another configuration material that is larger than the perforations is irradiated and the smaller material is removed by the screening process or recycled. In this kind of a configuration, the conveyor itself (for example a part of the conveyor) can be perforated or made with a mesh. For example, in one particular embodiment the biomass material may be wet and the perforations or mesh allow water to drain away from the biomass before irradiation.
Screening of material can also be by a manual method, for example by an operator or mechanoid (e.g., a robot equipped with a color, reflectivity or other sensor) that removes unwanted material. Screening can also be by magnetic screening wherein a magnet is disposed near the conveyed material and the magnetic material is removed magnetically.
Optional pre-treatment processing can include heating the material. For example a portion of the conveyor can be sent through a heated zone. The heated zone can be created, for example, by IR radiation, microwaves, combustion (e.g., gas, coal, oil, biomass), resistive heating and/or inductive coils. The heat can be applied from at least one side or more than one side, can be continuous or periodic and can be for only a portion of the material or all the material. For example, a portion of the conveying trough can be heated by use of a heating jacket. Heating can be, for example, for the purpose of drying the material. In the case of drying the material, this can also be facilitated, with or without heating, by the movement of a gas (e.g., air, oxygen, nitrogen, He, CO2, Argon) over and/or through the biomass as it is being conveyed.
Optionally, pre-treatment processing can include cooling the material. Cooling material is described in U.S. Pat. No. 7,900,857 to Medoff, the disclosure of which in incorporated herein by reference. For example, cooling can be by supplying a cooling fluid, for example water (e.g., with glycerol), or nitrogen (e.g., liquid nitrogen) to the bottom of the conveying trough. Alternatively, a cooling gas, for example, chilled nitrogen can be blown over the biomass materials or under the conveying system.
Another optional pre-treatment processing method can include adding a material to the biomass. The additional material can be added by, for example, by showering, sprinkling and or pouring the material onto the biomass as it is conveyed. Materials that can be added include, for example, metals, ceramics and/or ions as described in U.S. Pat. App. Pub. 2010/0105119 A1 (filed Oct. 26, 2009) and U.S. Pat. App. Pub. 2010/0159569 A1 (filed Dec. 16, 2009), the entire disclosures of which are incorporated herein by reference. Optional materials that can be added include acids and bases. Other materials that can be added are oxidants (e.g., peroxides, chlorates), polymers, polymerizable monomers (e.g., containing unsaturated bonds), water, catalysts, enzymes and/or organisms. Materials can be added, for example, in pure form, as a solution in a solvent (e.g., water or an organic solvent) and/or as a solution. In some cases the solvent is volatile and can be made to evaporate e.g., by heating and/or blowing gas as previously described. The added material may form a uniform coating on the biomass or be a homogeneous mixture of different components (e.g., biomass and additional material). The added material can modulate the subsequent irradiation step by increasing the efficiency of the irradiation, damping the irradiation or changing the effect of the irradiation (e.g., from electron beams to X-rays or heat). The method may have no impact on the irradiation but may be useful for further downstream processing. The added material may help in conveying the material, for example, by lowering dust levels.
Biomass can be delivered to the conveyor (e.g., the vibratory conveyors used in the vaults herein described) by a belt conveyor, a pneumatic conveyor, a screw conveyor, a hopper, a pipe, manually or by a combination of these. The biomass can, for example, be dropped, poured and/or placed onto the conveyor by any of these methods. In some embodiments the material is delivered to the conveyor using an enclosed material distribution system to help maintain a low oxygen atmosphere and/or control dust and fines. Lofted or air suspended biomass fines and dust are undesirable because these can form an explosion hazard or damage the window foils of an electron gun (if such a device is used for treating the material).
The material can be leveled to form a uniform thickness between about 0.0312 and 5 inches (e.g., between about 0.0625 and 2.000 inches, between about 0.125 and 1 inches, between about 0.125 and 0.5 inches, between about 0.3 and 0.9 inches, between about 0.2 and 0.5 inches between about 0.25 and 1.0 inches, between about 0.25 and 0.5 inches.
Generally, it is preferred to convey the material as quickly as possible through the electron beam to maximize throughput. For example the material can be conveyed at rates of at least 1 ft./min, e.g., at least 2 ft./min, at least 3 ft./min, at least 4 ft./min, at least 5 ft./min, at least 10 ft./min, at least 15 ft./min, 20, 25, 30, 35, 40, 45, 50 ft./min. The rate of conveying is related to the beam current, for example, for a 1⁄4 inch thick biomass and 100 mA, the conveyor can move at about 20 ft./min to provide a useful irradiation dosage, at 50 mA the conveyor can move at about 10 ft./min to provide approximately the same irradiation dosage.
After the biomass material has been conveyed through the radiation zone, optional post-treatment processing can be done. The optional post-treatment processing can, for example, be a process described with respect to the pre-irradiation processing. For example, the biomass can be screened, heated, cooled, and/or combined with additives. Uniquely to post-irradiation, quenching of the radicals can occur, for example, quenching of radicals by the addition of fluids or gases (e.g., oxygen, nitrous oxide, ammonia, liquids), using pressure, heat, and/or the addition of radical scavengers. For example, the biomass can be conveyed out of the enclosed conveyor and exposed to a gas (e.g., oxygen) where it is quenched, forming carboxylated groups. In one embodiment the biomass is exposed during irradiation to the reactive gas or fluid. Quenching of biomass that has been irradiated is described in U.S. Pat. No. 8,083,906 to Medoff, the entire disclosure of which is incorporate herein by reference.
If desired, one or more mechanical treatments can be used in addition to irradiation to further reduce the recalcitrance of the carbohydrate-containing material. These processes can be applied before, during and or after irradiation.
In some cases, the mechanical treatment may include an initial preparation of the feedstock as received, e.g., size reduction of materials, such as by comminution, e.g., cutting, grinding, shearing, pulverizing or chopping. For example, in some cases, loose feedstock (e.g., recycled paper, starchy materials, or switchgrass) is prepared by shearing or shredding. Mechanical treatment may reduce the bulk density of the carbohydrate-containing material, increase the surface area of the carbohydrate-containing material and/or decrease one or more dimensions of the carbohydrate-containing material.
Alternatively, or in addition, the feedstock material can be treated with another treatment, for example chemical treatments, such as with an acid (HCl, H2SO4, H3PO4), a base (e.g., KOH and NaOH), a chemical oxidant (e.g., peroxides, chlorates, ozone), irradiation, steam explosion, pyrolysis, sonication, oxidation, chemical treatment. The treatments can be in any order and in any sequence and combinations. For example, the feedstock material can first be physically treated by one or more treatment methods, e.g., chemical treatment including and in combination with acid hydrolysis (e.g., utilizing HCl, H2SO4, H3PO4), radiation, sonication, oxidation, pyrolysis or steam explosion, and then mechanically treated. This sequence can be advantageous since materials treated by one or more of the other treatments, e.g., irradiation or pyrolysis, tend to be more brittle and, therefore, it may be easier to further change the structure of the material by mechanical treatment. As another example, a feedstock material can be conveyed through ionizing radiation using a conveyor as described herein and then mechanically treated. Chemical treatment can remove some or all of the lignin (for example chemical pulping) and can partially or completely hydrolyze the material. The methods also can be used with pre-hydrolyzed material. The methods also can be used with material that has not been pre hydrolyzed The methods can be used with mixtures of hydrolyzed and non-hydrolyzed materials, for example with about 50% or more non-hydrolyzed material, with about 60% or more non-hydrolyzed material, with about 70% or more non-hydrolyzed material, with about 80% or more non-hydrolyzed material or even with 90% or more non-hydrolyzed material.
In addition to size reduction, which can be performed initially and/or later in processing, mechanical treatment can also be advantageous for “opening up,” “stressing,” breaking or shattering the carbohydrate-containing materials, making the cellulose of the materials more susceptible to chain scission and/or disruption of crystalline structure during the physical treatment.
Methods of mechanically treating the carbohydrate-containing material include, for example, milling or grinding. Milling may be performed using, for example, a hammer mill, ball mill, colloid mill, conical or cone mill, disk mill, edge mill, Wiley mill, grist mill or other mill. Grinding may be performed using, for example, a cutting/impact type grinder. Some exemplary grinders include stone grinders, pin grinders, coffee grinders, and burr grinders. Grinding or milling may be provided, for example, by a reciprocating pin or other element, as is the case in a pin mill. Other mechanical treatment methods include mechanical ripping or tearing, other methods that apply pressure to the fibers, and air attrition milling. Suitable mechanical treatments further include any other technique that continues the disruption of the internal structure of the material that was initiated by the previous processing steps.
Mechanical feed preparation systems can be configured to produce streams with specific characteristics such as, for example, specific maximum sizes, specific length-to-width, or specific surface areas ratios. Physical preparation can increase the rate of reactions, improve the movement of material on a conveyor, improve the irradiation profile of the material, improve the radiation uniformity of the material, or reduce the processing time required by opening up the materials and making them more accessible to processes and/or reagents, such as reagents in a solution.
The bulk density of feedstocks can be controlled (e.g., increased). In some situations, it can be desirable to prepare a low bulk density material, e.g., by densifying the material (e.g., densification can make it easier and less costly to transport to another site) and then reverting the material to a lower bulk density state (e.g., after transport). The material can be densified, for example from less than about 0.2 g/cc to more than about 0.9 g/cc (e.g., less than about 0.3 to more than about 0.5 g/cc, less than about 0.3 to more than about 0.9 g/cc, less than about 0.5 to more than about 0.9 g/cc, less than about 0.3 to more than about 0.8 g/cc, less than about 0.2 to more than about 0.5 g/cc). For example, the material can be densified by the methods and equipment disclosed in U.S. Pat. No. 7,932,065 to Medoff and International Publication No. WO 2008/073186 (which was filed Oct. 26, 2007, was published in English, and which designated the United States), the full disclosures of which are incorporated herein by reference. Densified materials can be processed by any of the methods described herein, or any material processed by any of the methods described herein can be subsequently densified.
In some embodiments, the material to be processed is in the form of a fibrous material that includes fibers provided by shearing a fiber source. For example, the shearing can be performed with a rotary knife cutter.
For example, a fiber source, e.g., that is recalcitrant or that has had its recalcitrance level reduced, can be sheared, e.g., in a rotary knife cutter, to provide a first fibrous material. The first fibrous material is passed through a first screen, e.g., having an average opening size of 1.59 mm or less ( 1/16 inch, 0.0625 inch), provide a second fibrous material. If desired, the fiber source can be cut prior to the shearing, e.g., with a shredder. For example, when a paper is used as the fiber source, the paper can be first cut into strips that are, e.g., 1⁄4- to 1⁄2-inch wide, using a shredder, e.g., a counter-rotating screw shredder, such as those manufactured by Munson (Utica, N.Y.). As an alternative to shredding, the paper can be reduced in size by cutting to a desired size using a guillotine cutter. For example, the guillotine cutter can be used to cut the paper into sheets that are, e.g., 10 inches wide by 12 inches long.
In some embodiments, the shearing of the fiber source and the passing of the resulting first fibrous material through a first screen are performed concurrently. The shearing and the passing can also be performed in a batch-type process.
For example, a rotary knife cutter can be used to concurrently shear the fiber source and screen the first fibrous material. A rotary knife cutter includes a hopper that can be loaded with a shredded fiber source prepared by shredding a fiber source.
In some implementations, the feedstock is physically treated prior to saccharification and/or fermentation. Physical treatment processes can include one or more of any of those described herein, such as mechanical treatment, chemical treatment, irradiation, sonication, oxidation, pyrolysis or steam explosion. Treatment methods can be used in combinations of two, three, four, or even all of these technologies (in any order). When more than one treatment method is used, the methods can be applied at the same time or at different times. Other processes that change a molecular structure of a biomass feedstock may also be used, alone or in combination with the processes disclosed herein.
Mechanical treatments that may be used, and the characteristics of the mechanically treated carbohydrate-containing materials, are described in further detail in U.S. Pat. App. Pub. 2012/0100577 A1, filed Oct. 18, 2011, the full disclosure of which is hereby incorporated herein by reference.
Sonication, Pyrolysis, Oxidation, Steam Explosion
If desired, one or more sonication, pyrolysis, oxidative, or steam explosion processes can be used instead of or in addition to irradiation to reduce or further reduce the recalcitrance of the carbohydrate-containing material. For example, these processes can be applied before, during and or after irradiation. These processes are described in detail in U.S. Pat. No. 7,932,065 to Medoff, the full disclosure of which is incorporated herein by reference.
Use of Treated Biomass Material
Using the methods described herein, a starting biomass material (e.g., plant biomass, animal biomass, paper, and municipal waste biomass) can be used as feedstock to produce useful intermediates and products such as organic acids, salts of organic acids, anhydrides, esters of organic acids and fuels, e.g., fuels for internal combustion engines or feedstocks for fuel cells. Systems and processes are described herein that can use as feedstock cellulosic and/or lignocellulosic materials that are readily available, but often can be difficult to process, e.g., municipal waste streams and waste paper streams, such as streams that include newspaper, kraft paper, corrugated paper or mixtures of these.
In order to convert the feedstock to a form that can be readily processed, the glucan- or xylan-containing cellulose in the feedstock can be hydrolyzed to low molecular weight carbohydrates, such as sugars, by a saccharifying agent, e.g., an enzyme or acid, a process referred to as saccharification. The low molecular weight carbohydrates can then be used, for example, in an existing manufacturing plant, such as a single cell protein plant, an enzyme manufacturing plant, or a fuel plant, e.g., an ethanol manufacturing facility.
The feedstock can be hydrolyzed using an enzyme, e.g., by combining the materials and the enzyme in a solvent, e.g., in an aqueous solution.
Alternatively, the enzymes can be supplied by organisms that break down biomass, such as the cellulose and/or the lignin portions of the biomass, contain or manufacture various cellulolytic enzymes (cellulases), ligninases or various small molecule biomass-degrading metabolites. These enzymes may be a complex of enzymes that act synergistically to degrade crystalline cellulose or the lignin portions of biomass. Examples of cellulolytic enzymes include: endoglucanases, cellobiohydrolases, and cellobiases (beta-glucosidases).
During saccharification a cellulosic substrate can be initially hydrolyzed by endoglucanases at random locations producing oligomeric intermediates. These intermediates are then substrates for exo-splitting glucanases such as cellobiohydrolase to produce cellobiose from the ends of the cellulose polymer. Cellobiose is a water-soluble 1,4-linked dimer of glucose. Finally, cellobiase cleaves cellobiose to yield glucose. The efficiency (e.g., time to hydrolyze and/or completeness of hydrolysis) of this process depends on the recalcitrance of the cellulosic material.
Intermediates and Products
Using the processes described herein, the biomass material can be converted to one or more products, such as energy, fuels, foods and materials. Specific examples of products include, but are not limited to, hydrogen, sugars (e.g., glucose, xylose, arabinose, mannose, galactose, fructose, disaccharides, oligosaccharides and polysaccharides), alcohols (e.g., monohydric alcohols or dihydric alcohols, such as ethanol, n-propanol, isobutanol, sec-butanol, tert-butanol or n-butanol), hydrated or hydrous alcohols (e.g., containing greater than 10%, 20%, 30% or even greater than 40% water), biodiesel, organic acids, hydrocarbons (e.g., methane, ethane, propane, isobutene, pentane, n-hexane, biodiesel, bio-gasoline and mixtures thereof), co-products (e.g., proteins, such as cellulolytic proteins (enzymes) or single cell proteins), and mixtures of any of these in any combination or relative concentration, and optionally in combination with any additives (e.g., fuel additives). Other examples include carboxylic acids, salts of a carboxylic acid, a mixture of carboxylic acids and salts of carboxylic acids and esters of carboxylic acids (e.g., methyl, ethyl and n-propyl esters), ketones (e.g., acetone), aldehydes (e.g., acetaldehyde), alpha and beta unsaturated acids (e.g., acrylic acid) and olefins (e.g., ethylene). Other alcohols and alcohol derivatives include propanol, propylene glycol, 1,4-butanediol, 1,3-propanediol, sugar alcohols (e.g., erythritol, glycol, glycerol, sorbitol threitol, arabitol, ribitol, mannitol, dulcitol, fucitol, iditol, isomalt, maltitol, lactitol, xylitol and other polyols), and methyl or ethyl esters of any of these alcohols. Other products include methyl acrylate, methyl methacrylate, lactic acid, citric acid, formic acid, acetic acid, propionic acid, butyric acid, succinic acid, valeric acid, caproic acid, 3-hydroxypropionic acid, palmitic acid, stearic acid, oxalic acid, malonic acid, glutaric acid, oleic acid, linoleic acid, glycolic acid, gamma-hydroxybutyric acid, and mixtures thereof, salts of any of these acids, mixtures of any of the acids and their respective salts.
Any combination of the above products with each other, and/or of the above products with other products, which other products may be made by the processes described herein or otherwise, may be packaged together and sold as products. The products may be combined, e.g., mixed, blended or co-dissolved, or may simply be packaged or sold together.
Any of the products or combinations of products described herein may be sanitized or sterilized prior to selling the products, e.g., after purification or isolation or even after packaging, to neutralize one or more potentially undesirable contaminants that could be present in the product(s). Such sanitation can be done with electron bombardment, for example, be at a dosage of less than about 20 Mrad, e.g., from about 0.1 to 15 Mrad, from about 0.5 to 7 Mrad, or from about 1 to 3 Mrad.
The processes described herein can produce various by-product streams useful for generating steam and electricity to be used in other parts of the plant (co-generation) or sold on the open market. For example, steam generated from burning by-product streams can be used in a distillation process. As another example, electricity generated from burning by-product streams can be used to power electron beam generators used in pretreatment.
The by-products used to generate steam and electricity are derived from a number of sources throughout the process. For example, anaerobic digestion of wastewater can produce a biogas high in methane and a small amount of waste biomass (sludge). As another example, post-saccharification and/or post-distillate solids (e.g., unconverted lignin, cellulose, and hemicellulose remaining from the pretreatment and primary processes) can be used, e.g., burned, as a fuel.
Other intermediates and products, including food and pharmaceutical products, are described in U.S. Pat. App. Pub. 2010/0124583 A1, published May 20, 2010, to Medoff, the full disclosure of which is hereby incorporated by reference herein.
Lignin Derived Products
The spent biomass (e.g., spent lignocellulosic material) from lignocellulosic processing by the methods described are expected to have a high lignin content and in addition to being useful for producing energy through combustion in a Co-Generation plant, may have uses as other valuable products. For example, the lignin can be used as captured as a plastic, or it can be synthetically upgraded to other plastics. In some instances, it can also be converted to lignosulfonates, which can be utilized as binders, dispersants, emulsifiers or as sequestrants.
When used as a binder, the lignin or a lignosulfonate can, e.g., be utilized in coal briquettes, in ceramics, for binding carbon black, for binding fertilizers and herbicides, as a dust suppressant, in the making of plywood and particle board, for binding animal feeds, as a binder for fiberglass, as a binder in linoleum paste and as a soil stabilizer.
As a dispersant, the lignin or lignosulfonates can be used, e.g., concrete mixes, clay and ceramics, dyes and pigments, leather tanning and in gypsum board.
As an emulsifier, the lignin or lignosulfonates can be used, e.g., in asphalt, pigments and dyes, pesticides and wax emulsions.
As a sequestrant, the lignin or lignosulfonates can be used, e.g., in micro-nutrient systems, cleaning compounds and water treatment systems, e.g., for boiler and cooling systems.
For energy production lignin generally has a higher energy content than holocellulose (cellulose and hemicellulose) since it contains more carbon than holocellulose. For example, dry lignin can have an energy content of between about 11,000 and 12,500 BTU per pound, compared to 7,000 an 8,000 BTU per pound of holocellulose. As such, lignin can be densified and converted into briquettes and pellets for burning. For example, the lignin can be converted into pellets by any method described herein. For a slower burning pellet or briquette, the lignin can be crosslinked, such as applying a radiation dose of between about 0.5 Mrad and 5 Mrad. Crosslinking can make a slower burning form factor. The form factor, such as a pellet or briquette, can be converted to a “synthetic coal” or charcoal by pyrolyzing in the absence of air, e.g., at between 400 and 950° C. Prior to pyrolyzing, it can be desirable to crosslink the lignin to maintain structural integrity.
Co-generation using spent biomass is described in U.S. Provisional Application No. 61/774,773 the entire disclosure therein is herein incorporated by reference.
Biomass Processing after Irradiation
After irradiation the biomass may be transferred to a vessel for saccharification. Alternately, the biomass can be heated after the biomass is irradiated prior to the saccharification step. The biomass can be, for example, by IR radiation, microwaves, combustion (e.g., gas, coal, oil, biomass), resistive heating and/or inductive coils. This heating can be in a liquid, for example, in water or other water-based solvents. The heat can be applied from at least one side or more than one side, can be continuous or periodic and can be for only a portion of the material or all the material. The biomass may be heated to temperatures above 90° C. in an aqueous liquid that may have an acid or a base present. For example, the aqueous biomass slurry may be heated to 90 to 150° C., alternatively, 105 to 145° C., optionally 110 to 140° C. or further optionally from 115 to 135° C. The time that the aqueous biomass mixture is held at the peak temperature is 1 to 12 hours, alternately, 1 to 6 hours, optionally 1 to 4 hours at the peak temperature. In some instances, the aqueous biomass mixture is acidic, and the pH is between 1 and 5, optionally 1 to 4, or alternately, 2 to 3. In other instances, the aqueous biomass mixture is alkaline and the pH is between 6 and 13, alternately, 8 to 12, or optionally, 8 to 11.
Saccharification
The treated biomass materials can be saccharified, generally by combining the material and a cellulase enzyme in a fluid medium, e.g., an aqueous solution. In some cases, the material is boiled, steeped, or cooked in hot water prior to saccharification, as described in U.S. Pat. App. Pub. 2012/0100577 A1 by Medoff and Masterman, published on Apr. 26, 2012, the entire contents of which are incorporated herein.
The saccharification process can be partially or completely performed in a tank (e.g., a tank having a volume of at least 4000, 40,000, or 500,000 L) in a manufacturing plant, and/or can be partially or completely performed in transit, e.g., in a rail car, tanker truck, or in a supertanker or the hold of a ship. The time required for complete saccharification will depend on the process conditions and the carbohydrate-containing material and enzyme used. If saccharification is performed in a manufacturing plant under controlled conditions, the cellulose may be substantially entirely converted to sugar, e.g., glucose in about 12-96 hours. If saccharification is performed partially or completely in transit, saccharification may take longer.
It is generally preferred that the tank contents be mixed during saccharification, e.g., using jet mixing as described in International App. No. PCT/US2010/035331, filed May 18, 2010, which was published in English as WO 2010/135380 and designated the United States, the full disclosure of which is incorporated by reference herein.
The addition of surfactants can enhance the rate of saccharification. Examples of surfactants include non-ionic surfactants, such as a Tween® 20 or Tween® 80 polyethylene glycol surfactants, ionic surfactants, or amphoteric surfactants.
It is generally preferred that the concentration of the sugar solution resulting from saccharification be relatively high, e.g., greater than 40%, or greater than 50, 60, 70, 80, 90 or even greater than 95% by weight. Water may be removed, e.g., by evaporation, to increase the concentration of the sugar solution. This reduces the volume to be shipped, and also inhibits microbial growth in the solution.
Alternatively, sugar solutions of lower concentrations may be used, in which case it may be desirable to add an antimicrobial additive, e.g., a broad spectrum antibiotic, in a low concentration, e.g., 50 to 150 ppm. Other suitable antibiotics include amphotericin B, ampicillin, chloramphenicol, ciprofloxacin, gentamicin, hygromycin B, kanamycin, neomycin, penicillin, puromycin, streptomycin. Antibiotics will inhibit growth of microorganisms during transport and storage, and can be used at appropriate concentrations, e.g., between 15 and 1000 ppm by weight, e.g., between 25 and 500 ppm, or between 50 and 150 ppm. If desired, an antibiotic can be included even if the sugar concentration is relatively high. Alternatively, other additives with anti-microbial of preservative properties may be used. Preferably the antimicrobial additive(s) are food-grade.
A relatively high concentration solution can be obtained by limiting the amount of water added to the carbohydrate-containing material with the enzyme. The concentration can be controlled, e.g., by controlling how much saccharification takes place. For example, concentration can be increased by adding more carbohydrate-containing material to the solution. In order to keep the sugar that is being produced in solution, a surfactant can be added, e.g., one of those discussed above. Solubility can also be increased by increasing the temperature of the solution. For example, the solution can be maintained at a temperature of 40-50° C., 60-80° C., or even higher.
Saccharifying Agents
Suitable cellulolytic enzymes include cellulases from species in the genera Bacillus, Coprinus, Myceliophthora, Cephalosporium, Scytalidium, Penicillium, Aspergillus, Pseudomonas, Humicola, Fusarium, Thielavia, Acremonium, Chrysosporium and Trichoderma, especially those produced by a strain selected from the species Aspergillus (see, e.g., EP Pub. No. 0 458 162), Humicola insolens (reclassified as Scytalidium thermophilum, see, e.g., U.S. Pat. No. 4,435,307), Coprinus cinereus, Fusarium oxysporum, Myceliophthora thermophila, Meripilus giganteus, Thielavia terrestris, Acremonium sp. (including, but not limited to, A. persicinum, A. acremonium, A. brachypenium, A. dichromosporum, A. obclavatum, A. pinkertoniae, A. roseogriseum, A. incoloratum, and A. furatum). Preferred strains include Humicola insolens DSM 1800, Fusarium oxysporum DSM 2672, Myceliophthora thermophila CBS 117.65, Cephalosporium sp. RYM-202, Acremonium sp. CBS 478.94, Acremonium sp. CBS 265.95, Acremonium persicinum CBS 169.65, Acremonium acremonium AHU 9519, Cephalosporium sp. CBS 535.71, Acremonium brachypenium CBS 866.73, Acremonium dichromosporum CBS 683.73, Acremonium obclavatum CBS 311.74, Acremonium pinkertoniae CBS 157.70, Acremonium roseogriseum CBS 134.56, Acremonium incoloratum CBS 146.62, and Acremonium furatum CBS 299.70H. Cellulolytic enzymes may also be obtained from Chrysosporium, preferably a strain of Chrysosporium lucknowense. Additional strains that can be used include, but are not limited to, Trichoderma (particularly T. viride, T reesei, and T. koningii), alkalophilic Bacillus (see, for example, U.S. Pat. No. 3,844,890 and EP Pub. No. 0 458 162), and Streptomyces (see, e.g., EP Pub. No. 0 458 162).
In addition to or in combination to enzymes, acids, bases and other chemicals (e.g., oxidants) can be utilized to saccharify lignocellulosic and cellulosic materials. These can be used in any combination or sequence (e.g., before, after and/or during addition of an enzyme). For example strong mineral acids can be utilized (e.g. HCl, H2SO4, H3PO4) and strong bases (e.g., NaOH, KOH).
Sugars
In the processes described herein, for example after saccharification, sugars (e.g., glucose and xylose) can be isolated. For example sugars can be isolated by precipitation, crystallization, chromatography (e.g., simulated moving bed chromatography, high pressure chromatography), centrifugation, extraction, any other isolation method known in the art, and combinations thereof.
Hydrogenation and Other Chemical Transformations
The processes described herein can include hydrogenation. For example glucose and xylose can be hydrogenated to sorbitol and xylitol respectively. Hydrogenation can be accomplished by use of a catalyst (e.g., Pt/gamma-Al2O3, Ru/C, Raney Nickel, or other catalysts know in the art) in combination with H2 under high pressure (e.g., 10 to 12000 psi). Other types of chemical transformation of the products from the processes described herein can be used, for example production of organic sugar derived products such (e.g., furfural and furfural-derived products). Chemical transformations of sugar derived products are described in U.S. application Ser. No. 13/934,704, filed Jul. 3, 2013, the disclosure of which is incorporated herein by reference in its entirety.
Fermentation
Yeast and Zymomonas bacteria, for example, can be used for fermentation or conversion of sugar(s) to alcohol(s). Other microorganisms are discussed below. The optimum pH for fermentations is about pH 4 to 7. For example, the optimum pH for yeast is from about pH 4 to 5, while the optimum pH for Zymomonas is from about pH 5 to 6. Typical fermentation times are about 24 to 168 hours (e.g., 24 to 96 hrs.) with temperatures in the range of 20° C. to 40° C. (e.g., 26° C. to 40° C.), however thermophilic microorganisms prefer higher temperatures.
In some embodiments, e.g., when anaerobic organisms are used, at least a portion of the fermentation is conducted in the absence of oxygen, e.g., under a blanket of an inert gas such as N2, Ar, He, CO2 or mixtures thereof. Additionally, the mixture may have a constant purge of an inert gas flowing through the tank during part of or all of the fermentation. In some cases, anaerobic condition, can be achieved or maintained by carbon dioxide production during the fermentation and no additional inert gas is needed.
In some embodiments, all or a portion of the fermentation process can be interrupted before the low molecular weight sugar is completely converted to a product (e.g., ethanol). The intermediate fermentation products include sugar and carbohydrates in high concentrations. The sugars and carbohydrates can be isolated via any means known in the art. These intermediate fermentation products can be used in preparation of food for human or animal consumption. Additionally or alternatively, the intermediate fermentation products can be ground to a fine particle size in a stainless-steel laboratory mill to produce a flour-like substance. Jet mixing may be used during fermentation, and in some cases saccharification and fermentation are performed in the same tank.
Nutrients for the microorganisms may be added during saccharification and/or fermentation, for example the food-based nutrient packages described in U.S. Pat. App. Pub. 2012/0052536, filed Jul. 15, 2011, the complete disclosure of which is incorporated herein by reference.
“Fermentation” includes the methods and products that are disclosed in WO 2013/096700, filed Dec. 22, 2012, and U.S. App. No. PCT/US2012/071083, filed Dec. 22, 2012, the contents of both of which are incorporated by reference herein in their entirety.
Mobile fermenters can be utilized, as described in International App. No. PCT/US2007/074028 (which was filed Jul. 20, 2007, was published in English as WO 2008/011598 and designated the United States) and has a US issued U.S. Pat. No. 8,318,453, the contents of which are incorporated herein in its entirety. Similarly, the saccharification equipment can be mobile. Further, saccharification and/or fermentation may be performed in part or entirely during transit.
Fermentation Agents
The microorganism(s) used in fermentation can be naturally-occurring microorganisms and/or engineered microorganisms. For example, the microorganism can be a bacterium (including, but not limited to, e.g., a cellulolytic bacterium), a fungus, (including, but not limited to, e.g., a yeast), a plant, a protist, e.g., a protozoa or a fungus-like protest (including, but not limited to, e.g., a slime mold), or an alga. When the organisms are compatible, mixtures of organisms can be utilized.
Suitable fermenting microorganisms have the ability to convert carbohydrates, such as glucose, fructose, xylose, arabinose, mannose, galactose, oligosaccharides or polysaccharides into fermentation products. Fermenting microorganisms include strains of the genus Saccharomyces spp. (including, but not limited to, S. cerevisiae (baker's yeast), S. distaticus, S. uvarum), the genus Kluyveromyces, (including, but not limited to, K. marxianus, K. fragilis), the genus Candida (including, but not limited to, C. pseudotropicalis, and C. brassicae), Pichia stipitis (a relative of Candida shehatae), the genus Clavispora (including, but not limited to, C. lusitaniae and C. opuntiae), the genus Pachysolen (including, but not limited to, P. tannophilus), the genus Bretannomyces (including, but not limited to, e.g., B. clausenii (Philippidis, G. P., 1996, Cellulose bioconversion technology, in Handbook on Bioethanol: Production and Utilization, Wyman, C. E., ed., Taylor & Francis, Washington, D.C., 179-212)). Other suitable microorganisms include, for example, Zymomonas mobilis, Clostridium spp. (including, but not limited to, C. thermocellum (Philippidis, 1996, supra), C. saccharobutylacetonicum, C. tyrobutyricum C. saccharobutylicum, C. Puniceum, C. beijernckii, and C. acetobutylicum), Moniliella spp. (including but not limited to M. pollinis, M. tomentosa, M. madida, M. nigrescens, M. oedocephali, M. megachiliensis), Yarrowia lipolytica, Aureobasidium sp., Trichosporonoides sp., Trigonopsis variabilis, Trichosporon sp., Moniliellaacetoabutans sp., Typhula variabilis, Candida magnoliae, Ustilaginomycetes sp., Pseudozyma tsukubaensis, yeast species of genera Zygosaccharomyces, Debaryomyces, Hansenula and Pichia, and fungi of the dematioid genus Torula (e.g., T. corallina).
Many such microbial strains are publicly available, either commercially or through depositories such as the ATCC (American Type Culture Collection, Manassas, Va., USA), the NRRL (Agricultural Research Service Culture Collection, Peoria, Ill., USA), or the DSMZ (Deutsche Sammlung von Mikroorganismen and Zellkulturen GmbH, Braunschweig, Germany), to name a few.
Commercially available yeasts include, for example, RED STAR®/Lesaffre Ethanol Red (available from Red Star/Lesaffre, USA), FALI® (available from Fleischmann's Yeast, a division of Burns Philip Food Inc., USA), SUPERSTART® (Lallemand Biofuels and Distilled Spirits, Canada), EAGLE C6 FUELTM or C6 FUELTM (available from Lallemand Biofuels and Distilled Spirits, Canada), GERT STRAND® (available from Gert Strand AB, Sweden) and FERMOL® (available from DSM Specialties).
Distillation
After fermentation, the resulting fluids can be distilled using, for example, a “beer column” to separate ethanol and other alcohols from the majority of water and residual solids. The vapor exiting the beer column can be, e.g., 35% by weight ethanol and can be fed to a rectification column. A mixture of nearly azeotropic (92.5%) ethanol and water from the rectification column can be purified to pure (99.5%) ethanol using vapor-phase molecular sieves. The beer column bottoms can be sent to the first effect of a three-effect evaporator. The rectification column reflux condenser can provide heat for this first effect. After the first effect, solids can be separated using a centrifuge and dried in a rotary dryer. A portion (25%) of the centrifuge effluent can be recycled to fermentation and the rest sent to the second and third evaporator effects. Most of the evaporator condensate can be returned to the process as fairly clean condensate with a small portion split off to waste water treatment to prevent build-up of low-boiling compounds.
Hydrocarbon-Containing Materials and Wood
In other embodiments utilizing the methods and systems described herein, hydrocarbon-containing materials can be processed. Any process described herein can be used to treat any hydrocarbon-containing material herein described. “Hydrocarbon-containing materials,” as used herein, is meant to include oil sands, oil shale, tar sands, coal dust, coal slurry, bitumen, various types of coal, and other naturally-occurring and synthetic materials that include both hydrocarbon components and solid matter. The solid matter can include wood, rock, sand, clay, stone, silt, drilling slurry, or other solid organic and/or inorganic matter. The term can also include waste products such as drilling waste and by-products, refining waste and by-products, or other waste products containing hydrocarbon components, such as asphalt shingling and covering, asphalt pavement, etc.
In yet other embodiments utilizing the methods and systems described herein, wood and wood containing produces can be processed. For example lumber products can be processed, e.g., boards, sheets, laminates, beams, particle boards, composites, rough cut wood, soft wood and hard wood. In addition cut trees, bushes, wood chips sawdust, roots, bark, stumps, decomposed wood and other wood containing biomass material can be processed.
Conveying Systems
Various conveying systems can be used to convey the biomass material, for example, to a vault and under an electron beam in a vault. Exemplary conveyors are belt conveyors, pneumatic conveyors, screw conveyors, carts, trains, trains or carts on rails, elevators, front loaders, backhoes, cranes, various scrapers and shovels, trucks, and throwing devices can be used. For example, vibratory conveyors can be used in various processes described herein, for example, as disclosed in US. Provisional Application 61/711,801 filed Oct. 10, 2012, the entire disclosure of which is herein incorporated by reference.
Other Embodiments
Any material, processes or processed materials discussed herein can be used to make products and/or intermediates such as composites, fillers, binders, plastic additives, adsorbents and controlled release agents. The methods can include densification, for example, by applying pressure and heat to the materials. For example composites can be made by combining fibrous materials with a resin or polymer. For example radiation cross-linkable resin, e.g., a thermoplastic resin can be combined with a fibrous material to provide a fibrous material/cross-linkable resin combination. Such materials can be, for example, useful as building materials, protective sheets, containers and other structural materials (e.g., molded and/or extruded products). Absorbents can be, for example, in the form of pellets, chips, fibers and/or sheets. Adsorbents can be used, for example, as pet bedding, packaging material or in pollution control systems. Controlled release matrices can also be the form of, for example, pellets, chips, fibers and or sheets. The controlled release matrices can, for example, be used to release drugs, biocides, fragrances. For example, composites, absorbents and control release agents and their uses are described in U.S. Serial No. PCT/US2006/010648, filed Mar. 23, 2006, and U.S. Pat. No. 8,074,910 filed Nov. 22, 2011, the entire disclosures of which are herein incorporated by reference.
In some instances the biomass material is treated at a first level to reduce recalcitrance, e.g., utilizing accelerated electrons, to selectively release one or more sugars (e.g., xylose). The biomass can then be treated to a second level to release one or more other sugars (e.g., glucose). Optionally, the biomass can be dried between treatments. The treatments can include applying chemical and biochemical treatments to release the sugars. For example, a biomass material can be treated to a level of less than about 20 Mrad (e.g., less than about 15 Mrad, less than about 10 Mrad, less than about 5 Mrad, less than about 2 Mrad) and then treated with a solution of sulfuric acid, containing less than 10% sulfuric acid (e.g., less than about 9%, less than about 8%, less than about 7%, less than about 6%, less than about 5%, less than about 4%, less than about 3%, less than about 2%, less than about 1%, less than about 0.75%, less than about 0.50%, less than about 0.25%) to release xylose. Xylose, for example that is released into solution, can be separated from solids and optionally the solids washed with a solvent/solution (e.g., with water and/or acidified water). Optionally, the solids can be dried, for example in air and/or under vacuum optionally with heating (e.g., below about 150 deg C., below about 120 deg C.) to a water content below about 25 wt. % (below about 20 wt. %, below about 15 wt. %, below about 10 wt. %, below about 5 wt. %). The solids can then be treated with a level of less than about 30 Mrad (e.g., less than about 25 Mrad, less than about 20 Mrad, less than about 15 Mrad, less than about 10 Mrad, less than about 5 Mrad, less than about 1 Mrad or even not at all) and then treated with an enzyme (e.g., a cellulase) to release glucose. The glucose (e.g., glucose in solution) can be separated from the remaining solids. The solids can then be further processed, for example utilized to make energy or other products (e.g., lignin derived products).
Flavors, Fragrances and Colorants
Any of the products and/or intermediates described herein, for example, produced by the processes, systems and/or equipment described herein, can be combined with flavors, fragrances, colorants and/or mixtures of these. For example, any one or more of (optionally along with flavors, fragrances and/or colorants) sugars, organic acids, fuels, polyols, such as sugar alcohols, biomass, fibers and composites can be combined with (e.g., formulated, mixed or reacted) or used to make other products. For example, one or more such product can be used to make soaps, detergents, candies, drinks (e.g., cola, wine, beer, liquors such as gin or vodka, sports drinks, coffees, teas), pharmaceuticals, adhesives, sheets (e.g., woven, none woven, filters, tissues) and/or composites (e.g., boards). For example, one or more such product can be combined with herbs, flowers, petals, spices, vitamins, potpourri, or candles. For example, the formulated, mixed or reacted combinations can have flavors/fragrances of grapefruit, orange, apple, raspberry, banana, lettuce, celery, cinnamon, chocolate, vanilla, peppermint, mint, onion, garlic, pepper, saffron, ginger, milk, wine, beer, tea, lean beef, fish, clams, olive oil, coconut fat, pork fat, butter fat, beef bouillon, legume, potatoes, marmalade, ham, coffee and cheeses.
Flavors, fragrances and colorants can be added in any amount, such as between about 0.001 wt. % to about 30 wt. %, e.g., between about 0.01 to about 20, between about 0.05 to about 10, or between about 0.1 wt. % to about 5 wt. %. These can be formulated, mixed and or reacted (e.g., with any one of more product or intermediate described herein) by any means and in any order or sequence (e.g., agitated, mixed, emulsified, gelled, infused, heated, sonicated, and/or suspended). Fillers, binders, emulsifier, antioxidants can also be utilized, for example protein gels, starches and silica.
In one embodiment the flavors, fragrances and colorants can be added to the biomass immediately after the biomass is irradiated such that the reactive sites created by the irradiation may react with reactive compatible sites of the flavors, fragrances, and colorants.
The flavors, fragrances and colorants can be natural and/or synthetic materials. These materials can be one or more of a compound, a composition or mixtures of these (e.g., a formulated or natural composition of several compounds). Optionally the flavors, fragrances, antioxidants and colorants can be derived biologically, for example, from a fermentation process (e.g., fermentation of saccharified materials as described herein). Alternatively, or additionally these flavors, fragrances and colorants can be harvested from a whole organism (e.g., plant, fungus, animal, bacteria or yeast) or a part of an organism. The organism can be collected and or extracted to provide color, flavors, fragrances and/or antioxidant by any means including utilizing the methods, systems and equipment described herein, hot water extraction, supercritical fluid extraction, chemical extraction (e.g., solvent or reactive extraction including acids and bases), mechanical extraction (e.g., pressing, comminuting, filtering), utilizing an enzyme, utilizing a bacteria such as to break down a starting material, and combinations of these methods. The compounds can be derived by a chemical reaction, for example, the combination of a sugar (e.g., as produced as described herein) with an amino acid (Maillard reaction). The flavor, fragrance, antioxidant and/or colorant can be an intermediate and or product produced by the methods, equipment or systems described herein, for example and ester and a lignin derived product.
Some examples of flavor, fragrances or colorants are polyphenols. Polyphenols are pigments responsible for the red, purple and blue colorants of many fruits, vegetables, cereal grains, and flowers. Polyphenols also can have antioxidant properties and often have a bitter taste. The antioxidant properties make these important preservatives. On class of polyphenols are the flavonoids, such as Anthocyanidines, flavanonols, flavan-3-ols, s, flavanones and flavanonols. Other phenolic compounds that can be used include phenolic acids and their esters, such as chlorogenic acid and polymeric tannins.
Among the colorants inorganic compounds, minerals or organic compounds can be used, for example titanium dioxide, zinc oxide, aluminum oxide, cadmium yellow (E.g., CdS), cadmium orange (e.g., CdS with some Se), alizarin crimson (e.g., synthetic or non-synthetic rose madder), ultramarine (e.g., synthetic ultramarine, natural ultramarine, synthetic ultramarine violet), cobalt blue, cobalt yellow, cobalt green, viridian (e.g., hydrated chromium(III)oxide), chalcophylite, conichalcite, cornubite, cornwallite and liroconite. Black pigments such as carbon black and self-dispersed blacks may be used.
Some flavors and fragrances that can be utilized include ACALEA TBHQ, ACET C-6, ALLYL AMYL GLYCOLATE, ALPHA TERPINEOL, AMBRETTOLIDE, AMBRINOL 95, ANDRANE, APHERMATE, APPLELIDE, BACDANOL®, BERGAMAL, BETA IONONE EPDXIDE, BETA NAPHTHYL ISO-BUTYL ETHER, BICYCLONONALACTONE, BORNAFIX®, CANTHOXAL, CASHMERAN®, CASHMERAN® VELVET, CASSIFFIX®, CEDRAFIX, CEDRAMBER®, CEDRYL ACETATE, CELESTOLIDE, CINNAMALVA, CITRAL DIMETHYL ACETATE, CITROLATETM, CITRONELLOL 700, CITRONELLOL 950, CITRONELLOL COEUR, CITRONELLYL ACETATE, CITRONELLYL ACETATE PURE, CITRONELLYL FORMATE, CLARYCET, CLONAL, CONIFERAN, CONIFERAN PURE, CORTEX ALDEHYDE 50% PEOMOSA, CYCLABUTE, CYCLACET®, CYCLAPROP®, CYCLEMAXTM, CYCLOHEXYL ETHYL ACETATE, DAMASCOL, DELTA DAMASCONE, DIHYDRO CYCLACET, DIHYDRO MYRCENOL, DIHYDRO TERPINEOL, DIHYDRO TERPINYL ACETATE, DIMETHYL CYCLORMOL, DIMETHYL OCTANOL PQ, DIMYRCETOL, DIOLA, DIPENTENE, DULCINYL® RECRYSTALLIZED, ETHYL-3-PHENYL GLYCIDATE, FLEURAMONE, FLEURANIL, FLORAL SUPER, FLORALOZONE, FLORIFFOL, FRAISTONE, FRUCTONE, GALAXOLIDE® 50, GALAXOLIDE® 50 BB, GALAXOLIDE® 50 IPM, GALAXOLIDE® UNDILUTED, GALBASCONE, GERALDEHYDE, GERANIOL 5020, GERANIOL 600 TYPE, GERANIOL 950, GERANIOL 980 (PURE), GERANIOL CFT COEUR, GERANIOL COEUR, GERANYL ACETATE COEUR, GERANYL ACETATE, PURE, GERANYL FORMATE, GRISALVA, GUAIYL ACETATE, HELIONALTM, HERBAC, HERBALIMETM, HEXADECANOLIDE, HEXALON, HEXENYL SALICYLATE CIS 3-, HYACINTH BODY, HYACINTH BODY NO. 3, HYDRATROPIC ALDEHYDE. DMA, HYDROXYOL, INDOLAROME, INTRELEVEN ALDEHYDE, INTRELEVEN ALDEHYDE SPECIAL, IONONE ALPHA, IONONE BETA, ISO CYCLO CITRAL, ISO CYCLO GERANIOL, ISO E SUPER®, ISOBUTYL QUINOLINE, JASMAL, JESSEMAL®, KHARISMAL®, KHARISMAL® SUPER, KHUSINIL, KOAVONE®, KOHINOOL®, LIFFAROMETM, LIMOXAL, LINDENOLTM, LYRAL®, LYRAME SUPER, MANDARIN ALD 10% TM ETH, CITR, MARITIMA, MCK CHINESE, MEIJIFFTM, MELAFLEUR, MELOZONE, METHYL ANTHRANILATE, METHYL IONONE ALPHA EXTRA, METHYL IONONE GAMMA A, METHYL IONONE GAMMA COEUR, METHYL IONONE GAMMA PURE, METHYL LAVENDER KETONE, MONTAVERDI®, MUGUESIA, MUGUET ALDEHYDE 50, MUSK Z4, MYRAC ALDEHYDE, MYRCENYL ACETATE, NECTARATETM, NEROL 900, NERYL ACETATE, OCIMENE, OCTACETAL, ORANGE FLOWER ETHER, ORIVONE, ORRINIFF 25%, OXASPIRANE, OZOFLEUR, PAMPLEFLEUR®, PEOMOSA, PHENOXANOL®, PICONIA, PRECYCLEMONE B, PRENYL ACETATE, PRISMANTOL, RESEDA BODY, ROSALVA, ROSAMUSK, SANJINOL, SANTALIFFTM, SYVERTAL, TERPINEOL, TERPINOLENE 20, TERPINOLENE 90 PQ, TERPINOLENE RECT., TERPINYL ACETATE, TERPINYL ACETATE JAX, TETRAHYDRO, MUGUOL®, TETRAHYDRO MYRCENOL, TETRAMERAN, TIMBERSILKTM, TOBACAROL, TRIMOFIX® O TT, TRIPLAL®, TRISAMBER®, VANORIS, VERDOXTM VERDOXTM HC, VERTENEX®, VERTENEX® HC, VERTOFIX® COEUR, VERTOLIFF, VERTOLIFF ISO, VIOLIFF, VIVALDIE, ZENOLIDE, ABS INDIA 75 PCT MIGLYOL, ABS MOROCCO 50 PCT DPG, ABS MOROCCO 50 PCT TEC, ABSOLUTE FRENCH, ABSOLUTE INDIA, ABSOLUTE MD 50 PCT BB, ABSOLUTE MOROCCO, CONCENTRATE PG, TINCTURE 20 PCT, AMBERGRIS, AMBRETTE ABSOLUTE, AMBRETTE SEED OIL, ARMOISE OIL 70 PCT THUYONE, BASIL ABSOLUTE GRAND VERT, BASIL GRAND VERT ABS MD, BASIL OIL GRAND VERT, BASIL OIL VERVEINA, BASIL OIL VIETNAM, BAY OIL TERPENELESS, BEESWAX ABS N G, BEESWAX ABSOLUTE, BENZOIN RESINOID SIAM, BENZOIN RESINOID SIAM 50 PCT DPG, BENZOIN RESINOID SIAM 50 PCT PG, BENZOIN RESINOID SIAM 70.5 PCT TEC, BLACKCURRANT BUD ABS 65 PCT PG, BLACKCURRANT BUD ABS MD 37 PCT TEC, BLACKCURRANT BUD ABS MIGLYOL, BLACKCURRANT BUD ABSOLUTE BURGUNDY, BOIS DE ROSE OIL, BRAN ABSOLUTE, BRAN RESINOID, BROOM ABSOLUTE ITALY, CARDAMOM GUATEMALA CO2 EXTRACT, CARDAMOM OIL GUATEMALA, CARDAMOM OIL INDIA, CARROT HEART, CASSIE ABSOLUTE EGYPT, CASSIE ABSOLUTE MD 50 PCT IPM, CASTOREUM ABS 90 PCT TEC, CASTOREUM ABS C 50 PCT MIGLYOL, CASTOREUM ABSOLUTE, CASTOREUM RESINOID, CASTOREUM RESINOID 50 PCT DPG, CEDROL CEDRENE, CEDRUS ATLANTICA OIL REDIST, CHAMOMILE OIL ROMAN, CHAMOMILE OIL WILD, CHAMOMILE OIL WILD LOW LIMONENE, CINNAMON BARK OIL CEYLAN, CISTE ABSOLUTE, CISTE ABSOLUTE COLORLESS, CITRONELLA OIL ASIA IRON FREE, CIVET ABS 75 PCT PG, CIVET ABSOLUTE, CIVET TINCTURE 10 PCT, CLARY SAGE ABS FRENCH DECOL, CLARY SAGE ABSOLUTE FRENCH, CLARY SAGE C'LESS 50 PCT PG, CLARY SAGE OIL FRENCH, COPAIBA BALSAM, COPAIBA BALSAM OIL, CORIANDER SEED OIL, CYPRESS OIL, CYPRESS OIL ORGANIC, DAVANA OIL, GALBANOL, GALBANUM ABSOLUTE COLORLESS, GALBANUM OIL, GALBANUM RESINOID, GALBANUM RESINOID 50 PCT DPG, GALBANUM RESINOID HERCOLYN BHT, GALBANUM RESINOID TEC BHT, GENTIANE ABSOLUTE MD 20 PCT BB, GENTIANE CONCRETE, GERANIUM ABS EGYPT MD, GERANIUM ABSOLUTE EGYPT, GERANIUM OIL CHINA, GERANIUM OIL EGYPT, GINGER OIL 624, GINGER OIL RECTIFIED SOLUBLE, GUAIACWOOD HEART, HAY ABS MD 50 PCT BB, HAY ABSOLUTE, HAY ABSOLUTE MD 50 PCT TEC, HEALINGWOOD, HYSSOP OIL ORGANIC, IMMORTELLE ABS YUGO MD 50 PCT TEC, IMMORTELLE ABSOLUTE SPAIN, IMMORTELLE ABSOLUTE YUGO, JASMIN ABS INDIA MD, JASMIN ABSOLUTE EGYPT, JASMIN ABSOLUTE INDIA, ASMIN ABSOLUTE MOROCCO, JASMIN ABSOLUTE SAMBAC, JONQUILLE ABS MD 20 PCT BB, JONQUILLE ABSOLUTE France, JUNIPER BERRY OIL FLG, JUNIPER BERRY OIL RECTIFIED SOLUBLE, LABDANUM RESINOID 50 PCT TEC, LABDANUM RESINOID BB, LABDANUM RESINOID MD, LABDANUM RESINOID MD 50 PCT BB, LAVANDIN ABSOLUTE H, LAVANDIN ABSOLUTE MD, LAVANDIN OIL ABRIAL ORGANIC, LAVANDIN OIL GROSSO ORGANIC, LAVANDIN OIL SUPER, LAVENDER ABSOLUTE H, LAVENDER ABSOLUTE MD, LAVENDER OIL COUMARIN FREE, LAVENDER OIL COUMARIN FREE ORGANIC, LAVENDER OIL MAILLETTE ORGANIC, LAVENDER OIL MT, MACE ABSOLUTE BB, MAGNOLIA FLOWER OIL LOW METHYL EUGENOL, MAGNOLIA FLOWER OIL, MAGNOLIA FLOWER OIL MD, MAGNOLIA LEAF OIL, MANDARIN OIL MD, MANDARIN OIL MD BHT, MATE ABSOLUTE BB, MOSS TREE ABSOLUTE MD TEX IFRA 43, MOSS-OAK ABS MD TEC IFRA 43, MOSS-OAK ABSOLUTE IFRA 43, MOSS-TREE ABSOLUTE MD IPM IFRA 43, MYRRH RESINOID BB, MYRRH RESINOID MD, MYRRH RESINOID TEC, MYRTLE OIL IRON FREE, MYRTLE OIL TUNISIA RECTIFIED, NARCISSE ABS MD 20 PCT BB, NARCISSE ABSOLUTE FRENCH, NEROLI OIL TUNISIA, NUTMEG OIL TERPENELESS, OEILLET ABSOLUTE, OLIBANUM RESINOID, OLIBANUM RESINOID BB, OLIBANUM RESINOID DPG, OLIBANUM RESINOID EXTRA 50 PCT DPG, OLIBANUM RESINOID MD, OLIBANUM RESINOID MD 50 PCT DPG, OLIBANUM RESINOID TEC, OPOPONAX RESINOID TEC, ORANGE BIGARADE OIL MD BHT, ORANGE BIGARADE OIL MD SCFC, ORANGE FLOWER ABSOLUTE TUNISIA, ORANGE FLOWER WATER ABSOLUTE TUNISIA, ORANGE LEAF ABSOLUTE, ORANGE LEAF WATER ABSOLUTE TUNISIA, ORRIS ABSOLUTE ITALY, ORRIS CONCRETE 15 PCT IRONE, ORRIS CONCRETE 8 PCT IRONE, ORRIS NATURAL 15 PCT IRONE 4095C, ORRIS NATURAL 8 PCT IRONE 2942C, ORRIS RESINOID, OSMANTHUS ABSOLUTE, OSMANTHUS ABSOLUTE MD 50 PCT BB, PATCHOULI HEART No 3, PATCHOULI OIL INDONESIA, PATCHOULI OIL INDONESIA IRON FREE, PATCHOULI OIL INDONESIA MD, PATCHOULI OIL REDIST, PENNYROYAL HEART, PEPPERMINT ABSOLUTE MD, PETITGRAIN BIGARADE OIL TUNISIA, PETITGRAIN CITRONNIER OIL, PETITGRAIN OIL PARAGUAY TERPENELESS, PETITGRAIN OIL TERPENELESS STAB, PIMENTO BERRY OIL, PIMENTO LEAF OIL, RHODINOL EX GERANIUM CHINA, ROSE ABS BULGARIAN LOW METHYL EUGENOL, ROSE ABS MOROCCO LOW METHYL EUGENOL, ROSE ABS TURKISH LOW METHYL EUGENOL, ROSE ABSOLUTE, ROSE ABSOLUTE BULGARIAN, ROSE ABSOLUTE DAMASCENA, ROSE ABSOLUTE MD, ROSE ABSOLUTE MOROCCO, ROSE ABSOLUTE TURKISH, ROSE OIL BULGARIAN, ROSE OIL DAMASCENA LOW METHYL EUGENOL, ROSE OIL TURKISH, ROSEMARY OIL CAMPHOR ORGANIC, ROSEMARY OIL TUNISIA, SANDALWOOD OIL INDIA, SANDALWOOD OIL INDIA RECTIFIED, SANTALOL, SCHINUS MOLLE OIL, ST JOHN BREAD TINCTURE 10 PCT, STYRAX RESINOID, STYRAX RESINOID, TAGETE OIL, TEA TREE HEART, TONKA BEAN ABS 50 PCT SOLVENTS, TONKA BEAN ABSOLUTE, TUBEROSE ABSOLUTE INDIA, VETIVER HEART EXTRA, VETIVER OIL HAITI, VETIVER OIL HAITI MD, VETIVER OIL JAVA, VETIVER OIL JAVA MD, VIOLET LEAF ABSOLUTE EGYPT, VIOLET LEAF ABSOLUTE EGYPT DECOL, VIOLET LEAF ABSOLUTE FRENCH, VIOLET LEAF ABSOLUTE MD 50 PCT BB, WORMWOOD OIL TERPENELESS, YLANG EXTRA OIL, YLANG III OIL and combinations of these.
The colorants can be among those listed in the Colour Index International by the Society of Dyers and Colourists. Colorants include dyes and pigments and include those commonly used for coloring textiles, paints, inks and inkjet inks. Some colorants that can be utilized include carotenoids, arylide yellows, diarylide yellows, β-naphthols, naphthols, benzimidazolones, diazo condensation pigments, pyrazolones, nickel azo yellow, phthalocyanines, quinacridones, perylenes and perinones, isoindolinone and isoindoline pigments, triarylcarbonium pigments, diketopyrrolo-pyrrole pigments, thioindigoids. Carotenoids include, alpha-carotene, beta-carotene, gamma-carotene, lycopene, lutein and astaxanthin, Annatto extract, Dehydrated beets (beet powder), Canthaxanthin, Caramel, β-Apo-8′-carotenal, Cochineal extract, Carmine, Sodium copper chlorophyllin, Toasted partially defatted cooked cottonseed flour, Ferrous gluconate, Ferrous lactate, Grape color extract, Grape skin extract (enocianina), Carrot oil, Paprika, Paprika oleoresin, Mica-based pearlescent pigments, Riboflavin, Saffron, Titanium dioxide, Tomato lycopene extract; tomato lycopene concentrate, Turmeric, Turmeric oleoresin, FD&C Blue No. 1, FD&C Blue No. 2, FD&C Green No. 3, Orange B, Citrus Red No. 2, FD&C Red No. 3, FD&C Red No. 40, FD&C Yellow No. 5, FD&C Yellow No. 6, Alumina (dried aluminum hydroxide), Calcium carbonate, Potassium sodium copper chlorophyllin (chlorophyllin-copper complex), Dihydroxyacetone, Bismuth oxychloride, Ferric ammonium ferrocyanide, Ferric ferrocyanide, Chromium hydroxide green, Chromium oxide greens, Guanine, Pyrophyllite, Talc, Aluminum powder, Bronze powder, Copper powder, Zinc oxide, D&C Blue No. 4, D&C Green No. 5, D&C Green No. 6, D&C Green No. 8, D&C Orange No. 4, D&C Orange No. 5, D&C Orange No. 10, D&C Orange No. 11, FD&C Red No. 4, D&C Red No. 6, D&C Red No. 7, D&C Red No. 17, D&C Red No. 21, D&C Red No. 22, D&C Red No. 27, D&C Red No. 28, D&C Red No. 30, D&C Red No. 31, D&C Red No. 33, D&C Red No. 34, D&C Red No. 36, D&C Red No. 39, D&C Violet No. 2, D&C Yellow No. 7, Ext. D&C Yellow No. 7, D&C Yellow No. 8, D&C Yellow No. 10, D&C Yellow No. 11, D&C Black No. 2, D&C Black No. 3 (3), D&C Brown No. 1, Ext. D&C, Chromium-cobalt-aluminum oxide, Ferric ammonium citrate, Pyrogallol, Logwood extract, 1,4-Bis[(2-hydroxy-ethyl)amino]-9,10-anthracenedione bis(2-propenoic)ester copolymers, 1,4-Bis [(2-methylphenyl)amino]-9,10-anthracenedione, 1,4-Bis[4-(2-methacryloxyethyl) phenylamino] anthraquinone copolymers, Carbazole violet, Chlorophyllin-copper complex, Chromium-cobalt-aluminum oxide, C.I. Vat Orange 1, 2-[[2,5-Diethoxy-4-[(4-methylphenyl)thiol]phenyl]azo]-1,3,5-benzenetriol, 16,23-Dihydrodinaphtho [2,3-a:2′,3′-i] naphth [2′,3′:6,7] indolo [2,3-c] carbazole-5,10,15,17,22,24-hexone, N,N′-(9,10-Dihydro-9,10-dioxo-1,5-anthracenediyl) bisbenzamide, 7,16-Dichloro-6,15-dihydro-5,9,14,18-anthrazinetetrone, 16,17-Dimethoxydinaphtho (1,2,3-cd:3′,2′,1′-lm) perylene-5,10-dione, Poly(hydroxyethyl methacrylate)-dye copolymers(3), Reactive Black 5, Reactive Blue 21, Reactive Orange 78, Reactive Yellow 15, Reactive Blue No. 19, Reactive Blue No. 4, C.I. Reactive Red 11, C.I. Reactive Yellow 86, C.I. Reactive Blue 163, C.I. Reactive Red 180, 4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one (solvent Yellow 18), 6-Ethoxy-2-(6-ethoxy-3-oxobenzo[b] thien-2(3H)-ylidene) benzo[b]thiophen-3(2H)-one, Phthalocyanine green, Vinyl alcohol/methyl methacrylate-dye reaction products, C.I. Reactive Red 180, C.I. Reactive Black 5, C.I. Reactive Orange 78, C.I. Reactive Yellow 15, C.I. Reactive Blue 21, Disodium 1-amino-4-[[4-[(2-bromo-1-oxoallyl)amino]-2-sulphonatophenyl]amino]-9,10-dihydro-9,10-dioxoanthracene-2-sulphonate (Reactive Blue 69), D&C Blue No. 9, [Phthalocyaninato(2-)] copper and mixtures of these.
Other than in the examples herein, or unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages, such as those for amounts of materials, elemental contents, times and temperatures of reaction, ratios of amounts, and others, in the following portion of the specification and attached claims may be read as if prefaced by the word “about” even though the term “about” may not expressly appear with the value, amount, or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains error necessarily resulting from the standard deviation found in its underlying respective testing measurements. Furthermore, when numerical ranges are set forth herein, these ranges are inclusive of the recited range end points (e.g., end points may be used). When percentages by weight are used herein, the numerical values reported are relative to the total weight.
Also, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of “1 to 10” is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10. The terms “one,” “a,” or “an” as used herein are intended to include “at least one” or “one or more,” unless otherwise indicated.
Any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.
While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

## Claims

1. A method of protecting material processing equipment, the method comprising;
conveying a biomass material under an electron beam on a conveyor; and
enclosing motor components in an equipment enclosure that does not surround the conveyor; and
purging the enclosure with a gas that has been filtered to remove ozone.

2. The method of claim 1 wherein the gas comprises air.

3. The method of claim 1, further comprising exchanging the gas in the equipment enclosure at an exchange rate of less than once every 10 minutes.

4. The method of claim 1, wherein the conveyor is disposed within a vault.

5. The method of claim 4, wherein the vault also contains irradiating equipment.

6. The method of claim 1, wherein the gas is provided from within the enclosure.

7. The method of claim 1, wherein the method further includes moving the equipment enclosure to access the motor components.

8. The method of claim 7, wherein the equipment enclosure is configured to be movable.

9. The method of claim 1, wherein the equipment enclosure includes lead.

10. The method of claim 1, wherein the exposure of the motor components to radiation is reduced by at least 10% as compared to the radiation exposure that would occur without the equipment enclosure.

11. The method of claim 10, wherein the exposure of the motor components to ionizing radiation is reduced by at least 20% as compared to the radiation exposure that would occur without the equipment enclosure.

12. The method of claim 11, wherein the exposure of the motor components to ionizing radiation is reduced by at least 30% as compared to the radiation exposure that would occur without the equipment enclosure.

13. The method of claim 12, wherein the exposure of the motor components to ionizing radiation is reduced by at least 50% as compared to the radiation exposure that would occur without the equipment enclosure.

14. The method of claim 13, wherein the exposure of the motor components to ionizing radiation is reduced by at least 70% as compared to the radiation exposure that would occur without the equipment enclosure.

15. The method of claim 1 wherein the enclosure is radiation opaque.

16. The method of claim 1, wherein the conveyor is a vibratory conveyor.

17. The method of claim 1 wherein the gas is selected from the group consisting of oxygen reduced air, nitrogen, argon, helium, carbon dioxide, and mixtures thereof.

18. The method of claim 16, further comprising providing a gap between the equipment enclosure and the vibratory conveyor to accommodate movement of components of the vibratory conveyor during use.