Liquefaction processes and systems and liquefaction process intermediate compositions

Liquefaction processes are provided that can include: providing a biomass slurry solution having a temperature of at least 300° C. at a pressure of at least 2000 psig; cooling the solution to a temperature of less than 150° C.; and depressurizing the solution to release carbon dioxide from the solution and form at least part of a bio-oil foam. Liquefaction processes are also provided that can include: filtering the biomass slurry to remove particulates; and cooling and depressurizing the filtered solution to form the bio-oil foam. Liquefaction systems are provided that can include: a heated biomass slurry reaction zone maintained above 300° C. and at least 2000 psig and in continuous fluid communication with a flash cooling/depressurization zone maintained below 150° C. and between about 125 psig and about atmospheric pressure. Liquefaction systems are also provided that can include a foam/liquid separation system. Liquefaction process intermediate compositions are provided that can include a bio-oil foam phase separated from an aqueous biomass solids solution.

TECHNICAL FIELD

The present disclosure relates to liquefaction processes and systems as well as liquefaction process intermediate compositions. These systems and processes can be used in the form of hydrothermal liquefaction and they can be used to perform hydrothermal liquefaction on biomass solutions to create a bio-oil.

BACKGROUND

Bio-oils can be created from the hydrothermal liquefaction of a biomass slurry. These processes present many challenges for performing the process efficiently on many levels. One challenge is the pumping of biomass slurries through process systems, as well as the separation of the bio-oils from the reaction solutions. The present disclosure provides liquefaction process systems and intermediate compositions that overcome drawbacks of the prior art.

SUMMARY OF THE DISCLOSURE

Liquefaction processes are provided that can include: providing a biomass slurry solution having a temperature of at least 300° C. at a pressure of at least 2000 psig; cooling the solution to a temperature of less than 150° C.; and depressurizing the solution to release carbon dioxide from the solution and form at least part of a bio-oil foam.

Liquefaction processes are also provided that can include: filtering the biomass slurry to remove particulates; and cooling and depressurizing the filtered solution to form a bio-oil foam.

Liquefaction systems are provided that can include: a heated biomass slurry reaction zone maintained above 300° C. and at least 2000 psig and in continuous fluid communication with a flash cooling/depressurization zone maintained below 150° C. and about atmospheric pressure.

Liquefaction systems are also provided that can include a flash depressurization zone maintained between about 125 psig and about atmospheric pressure in fluid communication with foam/liquid separation system.

Liquefaction process intermediate compositions are provided that can include a bio-oil foam phase separated from an aqueous biomass solids solution.

DESCRIPTION

The process systems and intermediate compositions of the present disclosure will be described with reference toFIGS. 1-7. Referring first toFIG. 1, a process system10is shown that includes a reaction zone12in fluid communication with a production zone14, yielding a process intermediate16. Entering the reaction zone12but not shown can be a biomass slurry solution. This biomass slurry solution can be provided to reaction zone12, and this biomass slurry solution can include biomass and water, for example.

Biomass sources suitable for use in this solution include but are not limited to agricultural residues (e.g., corn stover), forest residue (e.g., pine), industrial/municipal sludges, aquatic biomass sources (e.g., algae, kelp), high moisture biomass slurries, biosludge from wastewater treatment systems, sewage sludge from municipal treatment systems, wet biproducts from biorefinary operations, wet byproducts and residues from food processing, animal waste and waste from centralized animal raising facilities, organic chemical manufacturing wastewater streams, other organic contaminated industrial wastewaters. These biomass materials may be derived from, for example, organic materials, plants, algae, macroalgae, microalgae, photosynthetic cyanobacteria, animal waste, food processing wastes including, e.g., trimmings, culls, pomace, cooking water, washings, fermentation residuals, meat solid wastes, dairy liquid wastes, wood and other biomass materials, raw materials such as fruits, vegetables, fish, poultry, livestock, and combinations of these raw materials and others sources and feedstock materials including combinations of these various sources. Biomass slurry solution can be substantially liquid and have density of from 0.95 mg/ml to about 1.15 mg/ml. Wood oils are examples of liquid biomass slurry solutions and this liquid biomass may have a density within the 0.95 to 1.15 range.

The biomass slurry solution can have a minimum wt % of about 8 wt/wt % and can range up to as high as 35 wt/wt % with the balance being water. The balance can also include saltwater and/or mixtures of water and inorganics. The slurry solutions can be maintained at this concentration to allow efficient pumping of these solutions in a continuous or steady state reaction system as disclosed herein.

This biomass slurry solution can be provided to reaction zone12, and within reaction zone12, the biomass slurry solution can be increased to a temperature of at least 300° C. and a pressure of at least 2000 psig. According to example implementations, reaction zone12can also be configured to maintain the slurry from about 300° C. to about 350° C. and a pressure of from about 2000 psig to about 3000 psig. The biomass slurry solution can be processed at a liquid hourly space velocity in zone12from about 1 to about 10 L/L/h

From reaction zone12, the reacted slurry solution can proceed to production zone14. Production zone14can provide for the cooling, (which may be via heat exchange) of the reacted slurry solution to a temperature of less than 150° C. and/or the depressurizing of the solution to about atmospheric pressure. The reacted slurry solution can be cooled to below 110° C. as well. Upon depressurization, carbon dioxide can be released from the reacted slurry solution and form at least part of process intermediate16as a bio-oil foam. The bio-oil foam17that is formed resides above or is phase separated from the reacted aqueous solution18of the biomass slurry solution. The bio-oil foam composition16can be provided from production zone14as shown inFIG. 1.

Referring next toFIG. 2, production zone14may have a subzone such as filter zone20as shown in system20ofFIG. 2. Filter zone20can be configured to receive heated and pressurized biomass slurry solution from reactant zone12for example and filter same. According to one embodiment of the disclosure, the slurry solution at temperatures between 300° C. and 350° C. and pressures between 2000 psig and 3000 psig can be filtered to remove solids and particulates. This filtering can minimize the formation of emulsions during the preparation of intermediate composition16. The filter device can include a high crush rating or strength such as a stainless steel filter device. The device can have a filter breakthrough rating selected in the range between about 0.5% to about 2%. Example devices can have an internal filter with selected pore sizes including, e.g., 5 um pores rated to remove up to 98% of solids such as organic or inorganic solids including organic char. In alternative embodiments, filter zone20can include an internal filter with 18 μm pores configured to remove up to 100% of inorganic solids and precipitates from the solution that is passed from the reaction zone. Filtration zone20may include a top-down filter zone and may also include a woven filter design.

Referring next toFIG. 3, process system30can include as part of the production zone14as depicted in system30, cooling zone32in fluid communication with depressurization zone34to yield product intermediate16. As shown inFIG. 3, cooling zone32can include a zone that is configured to receive reacted biomass slurry at a temperature above 300° C. and reduce the temperature of that solution to below 150° C. or 110° C. in some embodiments, and in other embodiments, to a temperature of from between about 20° C. and 110° C. In certain specific implementations, the temperature can be reduced to 60° C. to 70° C. as well, for example.

Cooling zone32can be in fluid communication with, for example, filter zone20ofFIG. 2as part of production zone14, for example. Cooling zone32can be in fluid communication with a depressurization zone34wherein upon cooling, the pressure applied to the solution is rapidly changed from at least 2000 psig to less than 125 psig to about atmospheric pressure. According to some implementations, during this rapid depressurization, exsolvation of saturated CO2formed as a product in the reaction zone evolves and brings with it bio-oils from the aqueous solution to form a bio-oil foam or froth. The terms “bio-oil froth” and “bio-oil foam” are used interchangeably herein.

It has been discovered that this bio-oil foam or froth resides above the aqueous solution at atmospheric pressure and provides intermediate composition16that can be exploited to separate the foam from the liquid solution, and thereby acquire the bio-oil produced during the reaction phase. This foam can be separated from the solution in a separation zone that can be coupled in fluid communication to the production zone.

Referring toFIG. 4, according to another embodiment, a process system40can include a separation zone42down the process from production of the intermediate process composition16, and this separation zone can be in fluid communication, for example, with production zone14. Separation zone42for example of process system40can be utilized to separate the bio-oil foam from the aqueous solution upon which it resides. This separation can yield a bio-oil foam which can be collapsed later to form a liquid bio-oil. Separation zone42can include, for example, a configuration of weirs, condensers and/or traps that can be utilized to separate the foam from the liquid. According to example implementations, the separation zone can include at least two float traps, and in fluid communication with each of the two float traps can be a condenser, for example.

Referring next toFIG. 5, a more detailed process system is shown according to an embodiment of the disclosure, and this system50can include a feed tank and stirrer52which can be configured to receive the biomass slurry solution and coupled directly to this feed tank and stirrer can be syringe pumps54, for example, which are coupled to horizontal oil jacketed preheaters56which can be maintained at about 160° C. Horizontal oil jacketed preheaters56can have an interior diameter of about ½″ and can have a volume of about 210 ml. Coupled to these heaters can be a stir tank reactor58that can be heated with electric heat, and then coupled to a tubular reactor60which can be a vertical oil jacketed tubular reactor maintained at about 350° C. This reactor can have an inner diameter of about ½″ and a volume of about 127 ml. In fluid communication with the reactor60can be reaction zone1as item62. This can be a resistance heated zone and can be maintained at 350° C. and have a ½″ interior diameter and have a volume of 60 ml. In fluid communication with this zone can be resistance heated zone2as item64, which can also be a zone having a ½″ diameter and an 80 ml volume. The reactors60,62and64can form the herein described reaction zone, for example.

In fluid communication with reactor64can be an oil jacketed filter system66than can have an interior volume of about 670 ml. One side of this filter can be mixture and blow out pot assemblies68and70. In fluid communication with the filter can be a heat exchanger outlet72which can be maintained at about 60° C. to 70° C. as described in this particular embodiment, but as indicated herein can be maintained at less than 150° C., or 110° C. or between 20° C. and 100° C.

In direct fluid communication with this heat exchanger outlet can be a bypass direct pressure let down conduit78which provides the reacted, filtered, and cooled solution to a separation zone. This bypass system78can bypass oil jacketed liquid collectors76with valve system74, for example. Upon providing the cooled reacted solution to a separation zone which can include elements80-88, the foam from the formed foam intermediate process composition can be separated utilizing a system that includes a back pressure regulator80that can be maintained at about 20° C. as well as a float trap82which can be in fluid communication with a container84configured to receive overfill from float trap82. In fluid communication with float trap82can be sample collection assemblies86and88, for example, which are also coupled to exhaust system90.

Referring next toFIG. 6, a more detailed view of an example separation zone100is shown and in this separation zone, heated and reacted solution102can be rapidly cooled and then depressurized at section104after passing through a dome-loaded backpressure regulator106to produce the intermediate composition described herein. This intermediate composition can then be provided to an assembly that includes a condenser110in fluid communication with a float trap108. Gaseous exhaust from condenser110can be provided to a gas recovery system112as well as a second float trap114. Yields from float traps108and114can be provided to collector116, for example.

As shown inFIG. 7, an example depiction of the intermediate foam bio-oil is shown wherein the foam bio-oil resides above the processed solution. This intermediate solution heretofore has not been known. Utilizing the process systems of the present disclosure, mass yield to bio-oil can range from about 25 to 40 wt % on a dry ash-free biomass basis. As one example, a 20 wt % slurry solution with a mass yield of 35 wt % can produce a process product stream that is 7 wt % bio-oil with the balance being aqueous phase.

In compliance with the statute, embodiments of the invention have been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the entire invention is not limited to the specific features and/or embodiments shown and/or described, since the disclosed embodiments comprise forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.