Patent Description:
Pyrolysis refers to a thermochemical decomposition of organic material at elevated temperatures in the absence of oxygen. Depending on how a pyrolysis system is configured and operated, different pyrolysis products can be obtained. <CIT> discloses a coal liquefaction system for utilizing a hydrogenated vegetable oil to liquefy coal. <CIT> discloses the thermochemical decomposition of the carbonaceous feedstock to a reaction product using thermal energy transferred from a selected heat source via a supercritical fluid thermally coupling the feedstock and a selected heat source.

The subject matter for which protection is sought is defined by the independent claims.

The following drawing figures, which form a part of this application, are illustrative of described technology and are not meant to limit the scope of the invention as claimed in any manner, which scope shall be based on the claims appended hereto.

Before the flexible pyrolysis methods and systems are disclosed and described, it is to be understood that this disclosure is not limited to the particular structures, process steps, or materials disclosed herein, but is extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It must be noted that, as used in this specification, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a lithium hydroxide" is not to be taken as quantitatively or source limiting, reference to "a step" may include multiple steps, reference to "producing" or "products" of a reaction should not be taken to be all of the products of a reaction, and reference to "reacting" may include reference to one or more of such reaction steps. As such, the step of reacting can include multiple or repeated reaction of similar materials to produce identified reaction products.

Pitch refers to a collection of hydrocarbons including polyaromatic hydrocarbons that can be manufactured from coal, wood and other organic material. Pitch is characterized by having high (><NUM>% by weight) elemental carbon composition, high concentration of polycyclic aromatic hydrocarbons (PAHs), and a softening temperature, where the softening temperature can range from <NUM> to greater than <NUM> (measured using the Vicat method ASTM-D <NUM>). Generally, pitch suitable for carbon fiber will be capable of forming a high concentration of anisotropic mesophase pitch. It can be used as a base for coatings and paint, in roofing and paving, and as a binder in asphalt products. Pitch may also be used to create carbon fiber as discussed in greater detail below.

While the systems and methods below will be presented in terms of supercritical carbon dioxide, any supercritical fluid may be used such as water, methane, nitrous oxide, etc..

<FIG> illustrates, at a high-level, a simplified pyrolysis method that improves the relative amount of pitch produced from a given feedstock. In the method <NUM> shown, a carbonaceous feedstock material and water are subjected to a two-stage pyrolysis. The water may exist as moisture content within the feedstock. Alternatively, additional water may be added to the feedstock at some point before or during the pyrolysis.

The first stage is a low temperature pyrolysis operation <NUM> to remove C<NUM>-C<NUM> gases from the feedstock. In this stage <NUM>, the pyrolysis is performed at a lower temperature (e.g., <NUM>-<NUM> at from <NUM>-<NUM> MPa). The feedstock are heated to the first stage temperature and held at that temperature to generate and remove C<NUM>-C<NUM> gases from the feedstock. The gases in the pyrolysis reaction chamber are monitored and, when it is determined that the C<NUM>-C<NUM> gas concentration has begun to level off based on the operator's criteria, a higher temperature pyrolysis operation <NUM> is performed.

The first stage temperature may be selected based on prior knowledge of the properties of the feedstock or may be automatically determined based on a real-time analysis of the pyrolysis reaction and the products being generated. The first stage temperature may have a lower range selected from <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> and may have an upper range selected from <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> so that any combination of the aforementioned lower ranges and upper ranges may be used.

In the second stage pyrolysis operation <NUM>, the temperature is increased to from <NUM>-<NUM> at from <NUM>-<NUM> MPa, for example from <NUM>-<NUM> MPa, and held at that temperature for a period of time sufficient to generate pitch. As with the first stage, the amount of pyrolysis reaction products generated will level off over time as the system comes to equilibrium and the length of the second pyrolysis operation <NUM> is at the operator's discretion.

The second stage temperature may be selected based on prior knowledge of the properties of the feedstock or may be automatically determined based on a real-time analysis of the pyrolysis reaction and the products being generated. The second stage temperature may have a lower range selected from <NUM>, <NUM>, <NUM>, <NUM> <NUM>, and <NUM> and may have an upper range selected from <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> so that any combination of the aforementioned lower ranges and upper ranges may be used.

The pitch is then obtained in an extraction and separation operation <NUM>. In the extraction and separation operation <NUM> the pitch is extracted using a solvent, such as supercritical carbon dioxide (sCO<NUM>), the solvent and dissolved pitch removed from the reaction chamber, and then separated to produce a pitch product.

In order to obtain carbon fiber from the pitch, an optional (illustrated by dashed lines in the drawing) extrusion operation <NUM> may be performed in which the pitch is extruded into fibers of a desired cross-sectional profile and allowed to cool. The pitch may or may not be washed first, e.g., by toluene or other solvent, to remove unwanted products and refine the pitch further.

Experimental data for two stage process of <FIG> indicates that the quantity of pitch produced for a given feedstock is greater than would otherwise be obtained from the same feedstock using a single stage pyrolysis at the higher temperature. Without being bound to any particular theory, the two stage process above appears to remove lighter hydrocarbons from the feedstock in the first stage, which makes them unavailable to react with the larger hydrocarbon chains and aromatics during the second stage and this improves the relative amount of pitch generated.

The feedstock material may include any carbonaceous material known in the art. For example, the feedstock material may include, but is not limited to, coal, biomass, mixed-source biomaterial, peat, tar, plastic, refuse, and landfill waste. For example, in the case of coal, the feedstock may include, but is not limited to, bituminous coal, sub-bituminous coal, lignite, anthracite and the like. By way of another example, in the case of biomass, the feedstock may include a wood material, such as, but not limited to, softwoods or hardwoods. In the detailed experiments discussed herein, the feedstock is presented as coal. However, it will be understood that pitch may be equally generated from any other type of feedstock material and then subsequently used to generate carbon fiber in the same manner as described with coal.

It should be noted that any carbonaceous feedstock such as coal may include some amount of water. In addition, water may be added to the feedstock prior to or during pyrolysis in any of the methods and systems discussed herein to modify the products created by the reaction. Likewise, feedstock may be dried prior to pyrolysis to lower the amount of water available during the pyrolysis operation and such a drying operation may be part of any of the methods and systems discussed herein.

<FIG> illustrates a more detailed pyrolysis method of <FIG>. The method <NUM> begins by placing the feedstock material and water in a pyrolysis reaction chamber in a loading operation <NUM>. The feedstock material and/or the water may be preheated before placement into the pyrolysis reaction chamber. The amount of water used may be from <NUM>%-<NUM>% the weight of the dried feedstock material. The amount of water may be from <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% the weight of dried feedstock material on the low end and up to <NUM>%, <NUM>%, or <NUM>% on the high end. The water may be added separately or may already be in the feedstock material. For example, the feedstock material used is coal semi-saturated with water such that more than <NUM>% of the weight of the feedstock material is water and the water in the coal is used as the water for the loading operation <NUM>.

The loading operation may also include pressurizing the pyrolysis reaction chamber to the operating pressure (e.g., <NUM>-<NUM> MPa). This may include removing oxygen and adding pressurized CO<NUM> to the reaction chamber. The pressurized CO<NUM> may later be used as the solvent for extracting and removing the pitch and other soluble reaction products from the chamber.

The method <NUM> also includes heating pyrolysis reaction chamber to an intermediate temperature from <NUM> to <NUM> at from <NUM>-<NUM> MPa in an initial heating operation <NUM>. A narrower temperature range may be used such as from <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> at the lower end of the range and to <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> at the upper end of the range. The initial heating operation <NUM> may be performed before or after the loading operation <NUM>. The operation <NUM> may be performed to increase the temperature a fast as practicable with the given equipment so that the reactions at temperatures lower than the intermediate temperature are reduced.

The intermediate temperature is then maintained for a period of time in a first temperature hold operation <NUM>. The hold time may be preselected such as for <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or even <NUM> minutes. For example, the preselected hold time may be based on prior experiments. Alternatively, the hold time may be determined by monitoring the gases in the pyrolysis reaction chamber. For example, the concentration of one or more pyrolysis reaction product gases such as methane, ethane, butane, propane, or any other light gas reaction product is monitored. The concentration of the monitored gas or gases will rise initially and ultimately begin to level off roughly following an exponential curve. The hold time may be based on the monitored change in gas or gases concentration over time. For example, the first temperature hold operation <NUM> may be terminated when it is observed that the concentration of monitored gas or gases has increased by less than some threshold amount (e.g., <NUM>% or 100ppm) over some predetermined period (e.g., <NUM> seconds, <NUM> minute, <NUM> minutes, etc.). The amount of energy input into the chamber to maintain the pyrolysis temperature or any other parameter, such as visual or physical condition the feedstock material, may also be monitored to determine that the reaction has progressed to the operator's satisfaction.

A second heating operation <NUM> is then performed. In the second heating operation <NUM>, the temperature of the pyrolysis chamber and the feedstock material is raised to a pyrolysis temperature from <NUM> to <NUM>. For example, the second heating operation <NUM> may include heating the reaction chamber to from <NUM>, <NUM>, <NUM>, or <NUM> on the low end of the range to from <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> on the high end.

The pyrolysis temperature, which may also be referred to as the pitch production temperature, is then maintained for a second period of time from <NUM> minute to <NUM> hours in a second temperature hold operation <NUM>. Again, the second hold time may be preselected, for example based on prior experiments. Alternatively, the hold time may be determined by monitoring the one or more gases, which may or may be the same gas or gases monitored during the first temperature hold operation <NUM>, in the pyrolysis reaction chamber. The amount of energy input into the chamber to maintain the pyrolysis temperature or any other parameter, such as visual or physical condition the feedstock material, may also be monitored to determine that the reaction has progressed to the operator's satisfaction.

At the end of the second hold time, the pitch may be extracted and removed from the pyrolysis chamber in an extraction operation <NUM>.

A separation operation <NUM> may then be performed to separate the extracted pitch from the solvent. If the solvent is sCO<NUM> the separation operation <NUM> may include removing the sCO<NUM> and dissolved pyrolysis reaction products from the chamber from the chamber and reducing the temperature and pressure of the solvent until the pitch is obtained. For example, the sCO<NUM> may be passed through successive collection chambers, each at a different pressure-temperature combination, in order to fractionally remove components of the reaction products, including the pitch, that have different solubilities in carbon dioxide. One of the separation chambers may be maintained at a temperature and pressure particular to the condensation of pitch from the solvent. For example, pitch is obtained from CO<NUM> solvent in a chamber maintained at <NUM> or greater in temperature and <NUM> MPa or greater in pressure.

In order to obtain carbon fiber from the pitch, an optional (illustrated by dashed lines in the drawing) extrusion operation <NUM> may be performed in which the pitch is extruded into fibers of a desired cross-sectional profile and allowed to cool. The pitch may or may not be washed first to remove unwanted products and refine the pitch further prior to or after extrusion. Additionally, the extruded pitch may be drawn, dried, cooled, baked, heat-treated (in oxidative or inert environments), or otherwise post-processed to improve the properties of the fiber strand.

The method <NUM> described above was described in terms of a batch process in a single pyrolysis reaction chamber. Alternatively the method may be performed as a continuous or semi-continuous process using one or more pyrolysis reaction chambers. For example, the initial heating operation <NUM> and first temperature hold operation <NUM> may be performed in a first reaction chamber and then the contents may be transferred to a second chamber for the second heating operation <NUM> and second temperature hold operation <NUM>.

<FIG> is an example of a system <NUM> suitable for the pitch production methods described above. <FIG> illustrates a block diagram view of a system <NUM> for converting carbonaceous material to one or more reaction products. The system <NUM> includes a thermochemical conversion system <NUM>. The thermochemical conversion system <NUM> includes a thermochemical reaction chamber <NUM>, such as a pyrolysis reaction chamber, suitable for containing a volume of feedstock material and water <NUM> (e.g., carbonaceous material) and converting the feedstock material to one or more reaction products including pitch.

The system <NUM> includes one or more heat sources <NUM> and a thermal energy transfer system <NUM> for transferring thermal energy from the one or more heat sources <NUM> to the volume of feedstock <NUM> contained within the thermochemical reaction chamber <NUM>. The thermal energy transfer system <NUM> includes a heat transfer element <NUM>. The heat transfer element <NUM> includes a heat transfer loop filled with a supercritical fluid (e.g., sCO<NUM>) placed in thermal communication (e.g., directly or indirectly) with one or more portions of the one or more heat sources <NUM>.

The thermal energy transfer system is arranged to selectably place the volume of the supercritical fluid in thermal communication with the volume of feedstock contained within the thermochemical reaction chamber. In this regard, the thermal energy transfer system <NUM> selectably transfers thermal energy from the one or more heat sources <NUM> to the volume of feedstock <NUM> contained within the at least one thermochemical reaction chamber <NUM>. The thermochemical reaction chamber <NUM> pyrolyzes least a portion of the feedstock <NUM> to obtain one or more reaction products using the thermal energy carried to the feedstock via the supercritical fluid.

The supercritical fluid of system <NUM> may include any supercritical fluid known in the art suitable for transferring energy from the one or more heat sources <NUM> to the feedstock <NUM> contained in the thermochemical reaction chamber <NUM>. The supercritical fluid may include, but is not limited to, sCO<NUM>. Alternatively, the supercritical fluid includes, but is not limited to, water, methanol, ethanol, propanol, acetone. The supercritical fluid may be pressurized to high pressure within at least one of the heat transfer element <NUM> and the thermochemical reaction chamber <NUM>.

It is noted herein that the supercritical fluid of system <NUM>, such as, but not limited to CO<NUM>, may have low viscosity and surface tension, allowing such supercritical fluids to readily penetrate organic materials (e.g., coal). The penetration of the supercritical fluid into the feedstock <NUM> reduces the need for converting the feedstock <NUM> into fine particles prior to thermochemical reaction, thereby saving energy in the preparation of the feedstock material. In the case where the supercritical fluid is supercritical CO<NUM>, the supercritical fluid may be pressurized to above its critical pressure (<NUM> MPa) and critical temperature (<NUM>). It is noted herein that above these conditions, CO<NUM>, will display unique solvency properties, similar to organic solvents such as hexane, heptane, benzene, and toluene. The non-polar nature of supercritical CO<NUM> may facilitate the control of undesirable ionic secondary reactions that commonly occur in aqueous environments. Further, CO<NUM> will volatize when the system is depressurized below the critical conditions, which facilitates the recovery of oil with low content of water. Again, this may significantly reduce energy consumption during reaction product-supercritical fluid separation, described further herein, following pyrolysis. It is further noted herein that the supercritical fluid of system <NUM> applies heated and pressurized CO<NUM> to the feedstock material <NUM>, which provides for better control of reaction conditions (e.g., time, pressure, and temperature), thereby allowing for better selectivity of high-value targeted chemical compounds or fuel intermediates.

A supercritical fluid, such as supercritical CO<NUM>, may provide strong temperature and reaction time control via the injection of cooler supercritical fluid into the thermochemical reaction chamber <NUM> to quench the reaction or hotter supercritical fluid to accelerate the reaction. It is further recognized that since a number of supercritical fluids, such as supercritical CO<NUM>, can be efficiently compressed, pressure conditions within the thermochemical reaction chamber <NUM> may also be used to control thermochemical reactions within the thermochemical reaction chamber <NUM>.

The solubility of one or more reaction products, such as pitch, in the supercritical fluid may be controlled by adding or removing a polar material into the supercritical fluid. For example, the solubility of one or more oils in supercritical carbon dioxide may be controlled by the addition/removal of one or more materials including a polar molecule, such as, but not limited to, H<NUM>O, ethanol, methanol, higher alcohols, and the like. By way of another example, in the case where the feedstock material includes coal, the solubility of one or more oils in sCO<NUM> may be controlled by adding/removing one or more materials including a hydrogen donor molecule, such as, but is not limited to, H<NUM>, H<NUM>O, formic acid, tetralin, and any other hydrogen donor solvents known in the art.

It is recognized herein that feedstock <NUM> contained within the thermochemical reaction chamber <NUM> may include sufficient moisture and polar nature to adequately dissolve the one or more reaction products (e.g., bio-oil) in the supercritical fluid. As discussed further herein, the 'dryness' of the feedstock may be controlled by the thermochemical conversion system <NUM> (e.g., controlled via dryer <NUM>), allowing the thermochemical conversion system <NUM> to maintain a moisture content level within the feedstock <NUM> to a level sufficient for adequately dissolving one or more reaction products in the supercritical fluid.

Tthe supercritical fluid may contain one or more materials for enhancing one or more physical or thermochemical reactions in the system <NUM>. For example, the supercritical fluid may contain one or more catalysts, such as, but not limited to, metals, metal salts and organics. By way of another example, the supercritical fluid may contain one or more solutes, such as, but not limited to, alcohols, oils, hydrogen and hydrocarbons.

The one or more heat sources <NUM> may include any heat source known in the art suitable for providing thermal energy sufficient to heat the feedstock <NUM> to the selected temperatures used in the two stages of pyrolysis.

The one or more heat sources <NUM> include a non-CO<NUM> emitting heat source. The one or more heat sources <NUM> include one or more nuclear reactors. The one or more heat sources <NUM> may include any nuclear reactor known in the art. For example, the one or more heat sources <NUM> may include a liquid metal cooled nuclear reactor, a molten salt cooled nuclear reactor, a high temperature water cooled nuclear reactor, a gas cooled nuclear reactor and the like. By way of another example, the one or more heat sources <NUM> may include a pool reactor. By way of another example, the one or more heat sources <NUM> may include a modular reactor.

It is recognized herein that a nuclear reactor may generate temperatures sufficient to carry out pyrolysis (e.g., fast pyrolysis) of feedstock <NUM>. For example, a nuclear reactor heat source may generate temperatures in excess of <NUM>-<NUM>. In this regard, a nuclear reactor may be used to transfer thermal energy (e.g., at a temperature in excess of <NUM>-<NUM>. ) to the supercritical fluid. In turn, the supercritical fluid may transfer the nuclear reactor generated thermal energy to the feedstock <NUM> contained within the thermochemical reaction chamber <NUM>.

It is further noted herein that a nuclear reactor heat source may be particularly advantageous as a heat source in the context of system <NUM> because the thermochemical reaction temperatures of system <NUM> are within the range of operating temperatures for many nuclear reactors. Nuclear reactor heat may be used to create reaction products (e.g., pitch) in the thermochemical reaction chamber <NUM> at high efficiency since the nuclear reactor is operating at the reaction temperature for the thermochemical conversion (i.e., heat added at the thermochemical reaction temperature supplies the required reaction enthalpy).

As shown in <FIG>, the thermal energy transfer system <NUM> includes a direct heat exchange system configured to transfer thermal energy directly from the one or more heat sources <NUM> to the volume of the supercritical fluid of the heat transfer element <NUM>. The heat transfer element <NUM> is placed in direct thermal communication with a portion of the one or more heat sources <NUM>. For instance, in the case where the one or more heat sources <NUM> include a nuclear reactor, one or more coolant systems of the nuclear reactor may be integrated with the thermal energy transfer system <NUM>. In this regard, the nuclear reactor may utilize a supercritical fluid in one or more coolant systems, which may then be coupled directly to the thermochemical reaction chamber <NUM>. For example, a primary or intermediate coolant loop of the nuclear reactor may include a coolant fluid consisting of a supercritical fluid, such as supercritical CO<NUM>. Further, the coolant loop of the nuclear reactor may be directly coupled to the thermochemical reaction chamber <NUM> via the thermal energy transfer system <NUM> so as to intermix the supercritical fluid of the coolant loop of the nuclear reactor with the feedstock material <NUM> contained within the thermochemical reaction chamber <NUM>. In turn, upon transferring thermal energy from
the nuclear reactor to the feedstock material <NUM>, the thermal energy transfer system <NUM> may circulate the supercritical fluid coolant back to the nuclear reactor via return path <NUM>. It is further contemplated herein that the thermal energy transfer system <NUM> may include any number of filtration elements in order to avoid transfer of feedstock and/or reaction products to the coolant system(s) of the nuclear reactor.

Although not shown, the thermal energy transfer system <NUM> can include an indirect heat exchange system. The indirect heat exchange system can be configured to indirectly transfer thermal energy from the one or more heat sources <NUM> to the volume of the supercritical fluid contained within the heat transfer element <NUM>. The indirect heat exchange system can include an intermediate heat transfer element (not shown) configured to transfer thermal energy from the one or more heat source <NUM> to the intermediate heat transfer element. In turn, the intermediate heat transfer element may transfer thermal energy from the intermediate heat transfer element to the volume of the supercritical fluid contained within the heat transfer element <NUM>.

The intermediate heat transfer element may include an intermediate heat transfer loop and one or more heat exchangers. The intermediate heat transfer loop may include any working fluid known in the art suitable for transferring thermal energy. For example, the working fluid of the intermediate heat transfer loop may include, but is not limited to, a liquid salt, a liquid metal, a gas, a supercritical fluid (e.g., supercritical CO<NUM>) or water.

Further, as described previously herein, the heat transfer element <NUM> of the heat transfer system <NUM> may intermix the supercritical fluid contained within the heat transfer element <NUM> with the feedstock material <NUM> contained within the thermochemical reaction chamber <NUM>. In turn, upon transferring thermal energy from the heat source <NUM> to the feedstock material <NUM> via the heat transfer element <NUM>, the thermal energy transfer system <NUM> may re-circulate the supercritical fluid coolant via return path <NUM>.

It is noted herein that the above description of the direct and indirect coupling between the one or more heat sources <NUM> and the feedstock <NUM> is not limiting and is provided merely for illustrative purposes. It is recognized herein that in a general sense the integration between the one or more heat sources (e.g., nuclear reactor) and the thermochemical reaction chamber <NUM> may occur by transferring heat from a primary, intermediate, or ternary heat transfer system (e.g., coolant system) of the one or more heat sources <NUM> to the working fluid, such as supercritical CO<NUM>, of the thermochemical conversion system <NUM>. It is further recognized herein that this integration may be carried out using any heat transfer systems or devices known in the art, such as, but not limited to, one or more heat transfer circuits, one or more heat sinks, one or more heat exchangers and the like.

The thermal energy transfer system <NUM> includes a flow control system <NUM>. The flow control system <NUM> may be arranged to selectably place the supercritical fluid in thermal communication with the volume of feedstock contained within the thermochemical reaction chamber <NUM>. In this regard, the flow control system <NUM> may selectably transfer thermal energy from the one or more heat sources <NUM> to the volume of feedstock contained within thermochemical reaction chamber <NUM>. The flow control system <NUM> is positioned along the heat transfer element <NUM> (e.g., heat transfer loop) in order to control the flow of supercritical fluid through the heat transfer element <NUM>. In this regard, the flow control system <NUM> may control the flow of the supercritical fluid to the volume of feedstock <NUM>, thereby controlling the transfer of thermal energy to the feedstock <NUM>.

The flow control system <NUM> may include any flow control system known in the art suitable for controlling supercritical fluid flow from a first position to a second position. For example, the flow control system <NUM> may include, but is not limited to, to one or more control valves operably coupled to the heat transfer element <NUM> and suitable for establishing and stopping flow through the heat transfer element <NUM>. For instance, the flow control system <NUM> may include a manually controlled valve, a valve/valve actuator and the like.

The flow control system <NUM> may couple the thermal energy from the one or more heat sources <NUM> to an electrical generation system (not shown). For example, the flow control system <NUM> may establish a parallel coupling of heat source <NUM> generated heat to a turbine electric system and the thermochemical conversion system <NUM>. The thermochemical conversion system <NUM> may include multiple batch-type reaction systems, which may receive heat from the one or more heat sources <NUM> (e.g., nuclear reactor). In this manner, it is possible to run multiple batch processes, concurrently or sequentially, which address overall thermal and feedstock conversion needs. Heat may be transferred to one or more continuous thermochemical reactors while being coupled in parallel to one or more turbine electric system.

The system <NUM> includes a feedstock supply system <NUM>. The feedstock supply system <NUM> is operably coupled to the thermochemical reaction chamber <NUM> of the thermochemical conversion system <NUM>. The feedstock supply system <NUM> provides a volume of feedstock material and water <NUM> to the interior of the thermochemical reaction chamber <NUM>. The feedstock supply system <NUM> may include any supply system known in the art suitable for transferring a selected amount of feedstock material, such as solid material, particulate material or liquid material, from one or more feedstock sources to the interior of the thermochemical reaction chamber <NUM>. For example, the feedstock supply system <NUM> may include, but not limited, to a conveyor system, a fluid transfer system and the like.

The feedstock supply system <NUM> may include separate systems for transferring the feedstock and transferring additional water in the amount necessary for the desired reaction. Water may be added to the feedstock prior to the transfer of the feedstock into the reaction chamber <NUM>. This may be done in the feedstock supply system <NUM> or prior to receipt by the feedstock supply system <NUM>.

A moisture control system (not shown) may be provided to determine the moisture of the feedstock and add water if necessary. Such a system may include a moisture detector that continuously or periodically determines the moisture of the feedstock, compares the moisture to a target water content range and adds water if the moisture is below the target range. A dryer may also be provided in case the moisture is above the target range for drying the feedstock material <NUM>.

The feedstock material <NUM> may include any carbonaceous material known in the art. For example, the feedstock material <NUM> may include, but is not limited to, coal, biomass, mixed-source biomaterial, peat, tar, plastic, refuse, and landfill waste. For example, in the case of coal, the feedstock may include, but is not limited to, bituminous coal, sub-bituminous coal, lignite, anthracite and the like. By way of another example, in the case of biomass, the feedstock may include a wood material, such as, but not limited to, softwoods or hardwoods.

It is noted herein that the ability to control temperature, pressure, reaction time, pretreatment options, and post organic-product production options may allow for multiple types of carbonaceous feedstock to be utilized within the system <NUM>. In addition, the ability to co-utilize or switch between types of feedstock may improve the utilization of available resources and improve the overall pitch production economics.

Referring again to <FIG>, the thermochemical conversion system <NUM> includes any thermochemical reaction chamber <NUM> suitable for carrying out pyrolysis. The thermochemical reaction chamber <NUM> may be configured to carry out a pyrolysis reaction on the feedstock <NUM>. Alternatively, the thermochemical reaction chamber <NUM> can include a pyrolysis chamber. The thermochemical reaction chamber <NUM> can include a non-combustion or low-combustion pyrolysis chamber. The pyrolysis chamber of system <NUM> may encompass any thermochemical reaction chamber suitable for carrying out the thermochemical decomposition of organic molecules in the absence of oxygen or in a low oxygen environment.

The thermochemical reaction chamber <NUM> can include a fast pyrolysis reactor suitable for converting feedstock <NUM>, such as coal, to reaction products including pitch. A fast pyrolysis reactor may include any thermochemical reaction chamber capable of carrying out a thermochemical decomposition of organic molecules in the absence of oxygen (or in a reduced oxygen environment) within approximately two seconds. Fast pyrolysis is generally described by <NPL>. Pyrolysis and fast pyrolysis are also generally described by <NPL>.

The thermochemical reaction chamber <NUM> can include a supercritical pyrolysis reactor suitable for converting feedstock <NUM>, such as coal or biomass, to a reaction product, such as pitch. For the purposes of the present disclosure, a 'supercritical pyrolysis reactor' is interpreted to encompass any reactor, reaction vessel or reaction chamber suitable for carrying out a pyrolysis reaction of feedstock material using the thermal energy supplied from a supercritical fluid. The thermochemical reaction chamber <NUM> may include, but is not limited to, a fluidized bed reactor.

The thermochemical reaction chamber <NUM> may carry out one or more extraction processes on the feedstock. An extraction chamber operably coupled to the thermochemical reaction chamber <NUM> may carry out one or more extraction processes on the feedstock after either of the first or second stage of pyrolysis. The thermochemical reaction chamber <NUM> can be configured to remove additional compounds from the feedstock material prior to pyrolysis. For example, the thermochemical reaction chamber <NUM> may be configured to remove at least one of oils and lipids, sugars, or other oxygenated compounds. The extracted compounds may be collected and stored for the development of additional bio-derived products.

It may be advantageous to remove sugars from the feedstock material <NUM>. It is recognized herein that sugars caramelize at elevated temperature and may act to block the supercritical fluid, such as supercritical CO<NUM>, from entering the cellulose structure of the feedstock material <NUM>. In addition, sugars present in the thermochemical conversion system <NUM> may also act to harm downstream catalyst beds (if any). It is noted herein that the removal of sugars aids in avoiding the formation of oxygenated compounds such as, but not limited to, furfural, hydroxymethalfurfural, vanillin and the like.

The thermochemical conversion system <NUM> may extract materials from the feedstock <NUM> at temperatures below <NUM>. It is noted herein that it is beneficial to extract sugars at temperatures below <NUM> as fructose, sucrose and maltose each caramelize at temperatures below approximately <NUM>. In this regard, the supercritical fluid, through the deconstruction of cellulosic material and the sweeping away of sugars, may serve to extract sugars from the feedstock <NUM> prior to the elevation of temperatures during pyrolysis.

The thermochemical reaction chamber <NUM> may be configured to pre-heat the feedstock <NUM> prior to thermal decomposition. Alternatively, a pre-heating chamber operably coupled to the thermochemical reaction chamber <NUM> is configured to pre-heat the feedstock <NUM> prior to thermal decomposition. For example, the thermochemical reaction chamber <NUM> (or the pre-heating chamber) may pre-heat the feedstock material to a temperature at or near the temperature necessary for liquefaction and/or pyrolysis.

The thermochemical reaction chamber <NUM> can be configured to pre-treat the feedstock <NUM> prior to thermal decomposition. For example, the thermochemical reaction chamber <NUM> may pre-hydrotreat the feedstock material with hydrogen prior to liquefaction and/or pyrolysis. For instance, pre-treating the feedstock material with hydrogen may aid in removing materials such as, but not limited to, sulfur, as well as serving to donate hydrogen to reactive species (i.e., stabilizing free radicals).

Although not shown, the thermochemical conversion system <NUM> can be separated into multiple process chambers for carrying out the various steps of the multi-stage thermochemical process of system <NUM>. For example, a first chamber is provided for the first stage of pyrolysis at the intermediate temperature, a second stage is provided for the second stage of pyrolysis at the pyrolysis temperature and an extraction chamber is provided for solvent contacting and extracting the solvent with the desired pitch product. The feedstock <NUM> may be transferred between the chambers continuously or as a batch process.

Applicants note that while the above description points out that the pyrolysis reaction chambers and extraction chamber may exist as separate chambers, this should not be interpreted as a limitation. Rather, it is contemplated herein that two or more of the thermochemical steps may each be carried out in a single reaction chamber.

The thermochemical reaction chamber <NUM> may include a multi-stage single thermochemical reaction chamber. The thermochemical conversion system <NUM> may be configured to transfer multiple portions of the supercritical fluid across multiple temperature ranges to the volume of feedstock <NUM> contained within the multi-stage single thermochemical reaction chamber <NUM> to perform a set of thermochemical reaction processes on the at least a portion of the volume of feedstock.

The thermal energy transfer system <NUM> may be configured to transfer a first portion of the supercritical fluid in a second temperature range to the volume of feedstock <NUM> contained within the single thermochemical reaction chamber <NUM> to perform a pre-heating process on at least a portion of the volume of feedstock.

The thermal energy transfer system <NUM> may be configured to transfer a second portion of the supercritical fluid in a first temperature range to the volume of feedstock <NUM> contained within the single thermochemical reaction chamber <NUM> to perform the first stage of pyrolysis on at least a portion of the volume of feedstock.

The thermal energy transfer system <NUM> may be configured to transfer a third portion of the supercritical fluid in a second temperature range to the volume of feedstock <NUM> contained within the single thermochemical reaction chamber <NUM> to perform the second stage of pyrolysis on at least a portion of the volume of feedstock.

The flow and temperature of the supercritical fluid can be varied spatially across the thermochemical reaction chamber <NUM>. For example, in order to vary flow and/or temperature across the reaction chamber <NUM>, multiple flows of supercritical fluid, each at a different temperature, may be established prior to entering the single reaction chamber. In this regard, in a vertical reaction chamber, the flow rate and temperature at a number of spatial locations, corresponding to the various thermochemical stages, may be varied. By way of another example, the temperature of the supercritical fluid may be varied along the length of the thermochemical reaction chamber <NUM> by flowing the supercritical fluid along the length of the thermochemical reaction chamber <NUM>. For instance, a flow of low temperature supercritical CO<NUM> may be combined with a flow of CO<NUM> at a higher temperature (e.g., between <NUM> to <NUM>. ) to dissolve sugars. At another point downstream (e.g., <NUM>-<NUM> meters downstream with an average flow rate of <NUM>-<NUM>/s), supercritical CO<NUM> at or above pyrolysis temperatures is mixed into the chamber. By staging the temperatures of the various thermochemical reaction steps according to length, the flow rate may be used to control reaction times.

It is further contemplated that two or more thermochemical steps, such as pyrolysis, extraction and separation, are carried out in the thermochemical chamber <NUM>, while additional steps, such as drying and pre-heating are carried out in a dedicated chamber operably coupled to the thermochemical reaction chamber <NUM>.

Reaction chambers may include one or more outlets <NUM>. As shown in <FIG>, the reaction chamber <NUM> is provided with an outlet for removing the feedstock residue remaining after the second stage of pyrolysis and another outlet for removing the solvent laden with the pitch and other dissolved pyrolysis products. The outlet for the feedstock residue remaining after the second stage of pyrolysis is complete is arranged to remove the residue and transfer it to a residue storage system <NUM>. The residue storage system <NUM> may be as simple as a drum, railcar, Conex box or other portable container. The residue may be stored in piles for later transport.

The solvent outlet <NUM> transfers the solvent, for example sCO<NUM>, to a separation system <NUM>. The outlet ca include a valve that controls the flow of gas from the reaction chamber <NUM> to the separation system <NUM>.

The separation system <NUM> in successive steps reduces the temperature and/or pressure to obtain different dissolved components. For example, optionally a heat rejection heat exchanger could be used before or after the separation system <NUM>. In one of these steps, the pitch is condensed and transferred to a pitch extruder <NUM>. The pitch may be stored intermediately in a holding container. Alternatively, the pitch may be immediately passed to the extruder <NUM> upon condensing out of the sCO<NUM>.

Each step corresponds to a collection chamber maintained at a different condition of temperature and pressure in which dissolved products are allowed to condense from the solvent. Each chamber, then, collects those products that condense at the temperature and pressure of that chamber. Pitch can be obtained from a chamber maintained at <NUM> or greater in temperature and <NUM> MPa or greater in pressure.

The pitch extruder, as discussed above, extrudes the pitch into fibers which are then allowed to cool for use directly or indirectly as carbon fiber.

Other compounds in the solvent stream removed from the reaction chamber <NUM> are collected for further treatment or sale in a product collection system <NUM>. A volatile gas separator and storage system may be provided as part of the product collection system <NUM> or the separation system <NUM>. The volatile gas separator may separate one or more volatile gases from the remainder of the one or more reaction products. For example, the volatile gas separator may separate volatile gases such as, but not limited to, CH<NUM>, C<NUM>H<NUM>, C<NUM>H<NUM>, CO, CO<NUM>, H<NUM>, and/or H<NUM>O from the solid or liquid reaction products. It is noted herein that the volatile gas separator may include any volatile gas separation device or process known in the art. It is further recognized that these gases may be cooled, cleaned, collected and stored for future utilization. Volatile gases may be produced in order to provide a hydrogen source.

As shown, the CO<NUM> is returned <NUM> to the heat source <NUM> for reuse after the dissolved products are removed in a closed loop system. In an alternative the CO<NUM> is simply vented.

Although not shown, the system <NUM> may include a heat recovery system. In the case of recovery, the system may recover heat from the sCO<NUM> prior to or as part of the separation system <NUM> (or any other appropriate sub-system of system <NUM>) via a heat transfer loop acting to thermally couple the sCO<NUM> and the heat recovery system. The recovered heat may serve as a recuperator or regenerator. Energy may be recovered following the thermochemical process carried out by chamber <NUM>. The recovered energy may be used to pre-heat feedstock material prior to thermochemical processing. The recovered energy may be used to produce ancillary power (e.g., mechanical power or electrical power) to one or more sub-systems of the system <NUM>.

<FIG> illustrates a process flow diagram for a batch flexible pyrolysis system that can be tuned to change the pyrolysis products obtained from a given feedstock. As shown, the feedstock will be presented as coal. However, the reader will understand that any carbonaceous feedstock may be used such as biomass.

<FIG> illustrates a closed-loop CO<NUM> pyrolysis system similar in operation to those described above. As shown in <FIG>, the pyrolysis chamber is a column <NUM> filled with coal <NUM>. An inlet stream of supercritical fluid such as sCO<NUM> enters the top of the column and flows through the coal <NUM>. By controlling the flow rate of sCO<NUM>, the residence or contact time of the sCO<NUM> with the coal may be controlled as is known in the art in order to control the amount of dissolved reaction products in the sCO<NUM> observed in the outlet stream of the chamber. The sCO<NUM> entering the pyrolysis chamber <NUM> can range in temperature from <NUM>-<NUM> and in pressure from <NUM>-<NUM> MPa so that the pyrolysis occurs with the CO<NUM> atmosphere in a supercritical state. Higher temperatures and pressures may also be used.

In a batch system, the pyrolysis chamber may be a simple cylindrical chamber without any internal components other than a screen to maintain the coal in place. Multiple chambers may be provided in parallel so that one may be in use while the char is removed from the others and they are recharged with new coal. Alternatively, the chamber may be provided with agitators or screws for moving the coal during the pyrolysis.

After contacting and pyrolyzing the coal <NUM>, sCO<NUM> exits the bottom of the column <NUM> with dissolved pyrolysis products as described above. The output sCO<NUM> is then passed through a recuperating and condensing circuit that removes the dissolved pyrolysis products and then recuperates the CO<NUM> for reuse in the pyrolysis chamber <NUM>. The recuperating and condensing circuit includes a series one or more recuperators <NUM> that simultaneously cool the CO<NUM> stream output by the pyrolysis chamber <NUM> while preheating the inlet/return stream of CO<NUM> (in which the products have mostly been condensed out of the stream) delivered to the chamber <NUM>. In the system <NUM> shown, four recuperators <NUM> are illustrated, a first stage recuperator 406a, a second stage 406b, a third stage 406c and a fourth stage 406d. More or fewer recuperators <NUM> may be used as desired, as described below.

The recuperators <NUM> may be any type of heat exchanger now know or later developed. For example, the recuperators <NUM> are each tube-in-tube heat exchangers with the output CO<NUM> in the outer tube and the cooler, inlet CO<NUM> stream flowing through the inner tube. However, any type of heat exchanger may be used in any configuration determined to be beneficial or desired.

In addition to the recuperators <NUM>, an optional final cooling heat exchanger <NUM> stage may be provided as part of the recuperating and condensing circuit to perform the final reduction of temperature of the CO<NUM> to the desired low temperature of the circuit. This is achieved using a coolant, such as chilled water from a chilled water system <NUM> as shown, to perform the final cooling of the output stream. As with the recuperators <NUM>, the final heat exchanger <NUM> if utilized may be any type of heat exchanger.

As mentioned above, the supercritical conditions for CO<NUM> are a temperature above <NUM> and pressures above <NUM> MPa. In describing the system, CO<NUM> will be referred to as supercritical even though at some points in the system the conditions may fall below the critical point in either temperature or pressure. In those points, it should be understood that the CO<NUM> may be in a gas or liquid state depending on the temperature and pressure conditions. Such states may occur, for example, downstream of the pyrolyzer <NUM> such as in the fourth recuperator <NUM> or the final heat exchanger <NUM>.

For example, the low sCO<NUM> circuit temperature may be less than <NUM> such as room temperature (<NUM>) and the low pressure may be from <NUM>-<NUM> MPa. Lower temperatures and pressures may also be used. The CO<NUM> is allowed to go subcritical in order to remove as much of the pyrolysis products as possible. Alternatively, the circuit temperatures and pressures are maintained so that the CO<NUM> remains in a supercritical state throughout the system <NUM>.

As shown, after each heat exchanger in the circuit, there is a condensation collection vessel <NUM>. Each vessel is at a subsequently lower temperature, from left to right. The condensation vessel <NUM> may be any type of active or passive condensing apparatus. For example, the condensation vessel <NUM> is a cold finger condenser that provides a temperature-controlled surface over which the CO<NUM> flows. This causes any pyrolysis products condensable at or above the controlled temperature to collect in the condensation vessel <NUM>. Alternatively, instead of a cold finger condenser a cyclone separator may be used. Other possible condensation vessels include Liebig condensers, Graham condensers, coil condensers, and Allihn condensers, to name but a few.

Where appropriate, the term 'process stream' will be used to refer to the CO<NUM> stream in the portion of the CO<NUM> circuit with CO<NUM> flowing from the pyrolysis chamber <NUM> through the last condensation collection vessel <NUM>, while 'return stream' or 'inlet/return stream' will be used to refer to the CO<NUM> stream flowing through the circuit from the last condensation vessel, through the pump <NUM> and, ultimately, back into the pyrolysis chamber <NUM>. Note that the return stream may not be completely pure CO2 but will likely contain at least trace amounts of reaction products, water or other compounds that are not completely collected in the condensation vessels. The process stream, on the other hand, depending on the location within the circuit will contain at least some and possibly very large amounts of pyrolysis reaction products that will be sequentially removed by the various condensation vessels <NUM>.

As shown, the different recuperators may be operated at different temperatures. For example, the first recuperator 406a may receive the process stream of CO<NUM> and dissolved reaction products at about <NUM> and discharge it at <NUM>. The second recuperator 406b may receive the <NUM> stream and discharge it at <NUM>. The third recuperator 406c may receive the <NUM> stream and discharge it at <NUM>. The fourth recuperator 406d may receive the <NUM> stream and outputs it at <NUM>.

The return stream of CO<NUM> is partially reconditioned by a pump/compressor <NUM> that brings the CO<NUM> back up to operating pressure (e.g., approximately <NUM> MPa) and a heater <NUM> to provide additional heat to the CO<NUM> to bring it up to the desired pyrolysis temperature. For example, the pump/compressor <NUM> receives CO<NUM> at about <NUM> MPa and compresses the stream to about <NUM> MPa, which provides sufficient pressure to maintain the flow through the entire CO<NUM> circuit without any additional pumps. The heater <NUM> may be a single heating unit or multiple units in parallel and/or in series depending on operator preference. For example, three, separate heaters in series are provided that receive the recuperated CO<NUM> stream from the first recuperator 406a and heat the stream from an inlet temperature of about <NUM> to about <NUM>. Likewise, there may be a single pump <NUM> as shown, or multiple pumps distributed throughout the CO<NUM> circuit. For example, in a system in which a portion of circuit is below supercritical conditions, a dedicated heater and/or compressor (not shown) may be provided purely to recondition the CO<NUM> to supercritical.

By providing multiple stages of pairs of heat exchangers <NUM>, <NUM> followed by condensation vessels <NUM>, the pyrolysis products may be fractionated and collected by condensation temperature. This allows desired specific fractions to be easily separated as part of the recuperation process. By providing more or fewer stages, greater or lesser differentiation of the fractions may be achieved, as well as controlling the makeup of each fraction.

In addition to having multiple stages of heat exchangers <NUM>, <NUM> followed by condensation vessels <NUM>, further flexibility is obtained through the use of a bypass circuit created by a number of bypass valve <NUM> in the output CO<NUM> portion of the circuit and the inlet/return CO<NUM> portion of the circuit. One or more of the heat exchangers are equipped with bypass capability allowing that exchanger to be completely or partially bypassed by either or both of the pyrolysis output stream and the inlet/return stream. As shown, various bypass valves <NUM> are provided that allow each of the different stages to be either completely or partially bypassed as desired by the operator. At any bypass valve <NUM>, the operator may select how much of the input stream is directed to either outlet of the valve. This level of flow control provides significant flexibility in the operation of the system <NUM> and allows further operational control over where in the system the various fractions of the pyrolysis products are collected.

The pyrolysis system <NUM> may further be provided with additive injection systems for injecting additives into the CO2 inlet/return stream prior to delivery to the pyrolysis chamber <NUM>. As shown, two additive injection systems are shown, each including an injection pump <NUM> and an additive supply <NUM>. Examples of additives, described in greater detail above, include H<NUM>, H<NUM>O, formic acid, and tetralin. The injection pump <NUM> is an HPLC injection pump.

Although not shown, bypass valves <NUM> may be provided to allow one or more condensation vessels <NUM> to be bypassed. This allows collection of reaction products to be combined into fewer vessels as desired, thus further increasing the flexibility of the system <NUM>.

A controller <NUM> is illustrated in <FIG>. The controller <NUM> may be a programmable logic controller configured to monitor and control the pyrolysis system <NUM> to achieve desired results. Controllers may be implemented in many different manners, from purpose built hardware controllers to general purpose computing devices executing control software. Process controllers are well known in the art and any suitable controller design or combination of designs now known or later developed may be used.

The controller <NUM> controls the distribution of the flow of the process stream and the return stream through the various stages of recuperators. In this way, the inlet and outlet temperatures of the streams at each stage may be altered. The heat transfer equations governing the heat exchange between hot and cold streams in a heat exchanger are well known and any form of these equations may be used by the controller to determine the distribution of the flows among the stages in order to get specific temperatures at specific locations in the CO<NUM> circuit. For example, one basic heat exchanger equation that may be used is a general counterflow heat exchange equation describing the transfer of heat across a : <MAT> where ṁa is the mass flow rate of the process stream, cpa is the specific heat of the process stream, Ta1 is the inlet (high) temperature of the process stream entering the recuperator stage, Ta2 is the outlet (low) temperature of the process stream, ṁb is the mass flow rate of the return stream, cpb is the specific heat of the return stream, Tb1 is the inlet (low) temperature of the return stream entering the recuperator stage, and Tb2 is the outlet (high) temperature of the return stream. From the above equation, as is known in the art, additional equations can be derived which mathematically describe the performance of the recuperator, often in terms of an overall heat transfer coefficient for the recuperator based on its dimensions and characteristics. In many cases the performance equations for a heat exchanger may be provided by the manufacturer. Such equations, as necessary, are solved by the controller to determine how to distribute the flow of the streams through the recuperator stages in order to achieve the goals set by the operator, examples of which are provided below.

The controller <NUM> may be connected and capable of controlling the bypass valves <NUM>, the heater <NUM>, the chilled water system <NUM>, additive pumps <NUM>, and other components of the system <NUM>. In addition, the controller <NUM> may be connected to or otherwise receive information or signals from one or more monitoring devices <NUM>, from which the controller <NUM> receives data regarding the status of the system <NUM>.

<FIG> illustrates several monitoring devices <NUM> at various locations throughout the system <NUM>. Monitoring devices <NUM> may be any type of process monitor, analyzer, or sensor such as, for example, flow sensors, temperature sensors, pressure sensors, scales, pH sensors, spectrometers, photo-ionization detectors, gas chromatographs, catalytic sensors, infra-red sensors and flame ionization detectors, to name but a few. Monitoring devices <NUM> may be located anywhere in the system <NUM> as desired. For example, a gas chromatograph may be used to periodically or continuously monitor and determine the different compounds and their relative amounts in the reaction products in the sCO<NUM> leaving the reaction chamber <NUM>. Alternatively, liquid level sensors on each condensation vessel may be provided and from there data the relative production rate of each recuperator stage's condensates may be determined.

Based on information received from the monitoring devices <NUM>, the controller <NUM> may change the flow through one or more bypass valves and the temperatures of one or more streams to obtain a desired hydrocarbon condensate fraction (i.e., range of molecular weights) in one or more of the condensate vessels. For example, the controller may be directed to separate and recover hydrocarbons having boiling points from <NUM> to <NUM>. The flow through the various bypass valves may be adjusted so that the process stream is discharged from the first recuperator 406a at a temperature of <NUM> (as opposed to <NUM> as mentioned above) and discharged from the second recuperator 406b at a temperature of <NUM>. This may be achieved by bypassing a portion of the return stream around the second recuperator 406b so that a relatively larger and cooler return stream is driven through the first recuperator 406a, increasing the relative amount of cooling performed by the first stage. In this way, reaction products with boiling points above <NUM> are collected in the condensate vessel <NUM> between the first recuperator 406a and the second recuperator 406b while reaction products having boiling points from <NUM> to <NUM> are collected in the condensate vessel <NUM> following the second recuperator 406b.

As can be seen by the above example, through the use of the controller <NUM> and flexibility achieved by the system's design, the operating configuration of the system <NUM> may be changed in real time to achieve different goals. In addition, by basing the control of the system <NUM> on real-time knowledge reported by the sensors and monitoring devices, the system <NUM> can adjust over time in response to changing conditions such as changing feedstock quality. In this aspect, through the controller <NUM> and the multiple stages of recuperators and condensation vessels, the system <NUM> may be easily configured to separate and collect different fractions of hydrocarbons into different condensation vessels. By providing more stages, even more differentiation may be provided as required. Because the controller <NUM> can easily reconfigure the bypass valves <NUM>, the system <NUM> is uniquely capable of handling different output requirements or changes in feedstock characteristics.

In addition, the controller <NUM> may also be used to control and optimize the reaction products that are obtained from the pyrolysis reaction. For example, the controller <NUM> may directly or indirectly control the temperature and/or the pressure in the reaction chamber <NUM> to change the relative amounts of different reaction products. Changes in temperature or pressure in the reaction chamber may be done in real-time based on monitoring information received from the sensors and monitoring devices. For example, monitoring data indicative of the type and amount of different reaction products in the sCO<NUM> leaving the reaction chamber <NUM> may be provided to the controller <NUM>. In response to preset goals, such to optimize a subset of reaction products (e.g., maximize production of reaction products having boiling points from <NUM> to <NUM>), the controller <NUM> may then iteratively change the temperature and/or pressure in the reaction chamber until an optimized profile of reaction products is obtained based on the current goals of the system <NUM>.

<FIG> illustrate the experimental performance of the system shown in <FIG>. In the FIGS. , the system is alternately referred to as a multistage supercritical liquefaction system. In the experiment, the system shown in <FIG> was created at a bench scale using four recuperators and a final chilled water heat exchanger as illustrated. A <NUM> sample of Power River Basin subbituminous coal was placing in a column and pyrolyzed using sCO<NUM> as described above. A fine mesh screen was provided at the bottom of the column to prevent solids from exiting from the chamber.

For startup, the bypass circuit was used to isolate the pyrolysis chamber until the system reached the desired thermal conditions. After the loop achieved test temperatures, the bypass was disabled and the pyrolysis chamber was placed in the loop. The outlet temperature of the sCO<NUM> leaving the pyrolysis chamber was approximately <NUM> and the inlet temperature of the sCO<NUM> delivered to the pyrolysis chamber was approximately <NUM>. The pressure of the sCO<NUM> in the pyrolysis chamber was approximately <NUM> MPa and the mass flow rate of sCO<NUM> circulating through the circuit was between <NUM> and <NUM>/min during the experiment. The system was operated without bypassing any of the five heat exchangers such that the full flow of CO<NUM> passed through each exchanger/condensation vessel stage. The condenser vessels were cold fingers and designated as Bottles <NUM>-<NUM> maintained at the temperatures shown in <FIG>. The system was operated for a period of time then the condensed pyrolysis products from the condensation vessels were analyzed.

<FIG> illustrates a representative liquid yield obtain from pyrolyzing a batch of coal by condensation vessel temperature. The condenser vessels were cold fingers and designated as Bottles <NUM>-<NUM> maintained at the temperatures shown in <FIG>.

Mass spectroscopy was performed on the condensate fractions obtain from Bottles <NUM> and <NUM>. <FIG> shows the results for Bottle <NUM> and <FIG> shows the results for Bottle <NUM>. As expected the results show a substantially higher molecular weight product distribution was condensed in the higher temperature Bottle <NUM> than was obtained in the lower temperature Bottle <NUM>. This illustrates that the multistage separation system is successful in generating and fractionating different pyrolysis products from a carbonaceous feedstock.

<FIG> illustrates a broad method for pyrolyzing carbonaceous feedstock to obtain reaction products using CO<NUM>. The method shown is discussed in terms of an ongoing process that reconditions and recycles the CO<NUM> for reuse in a closed loop. The process in <FIG> is illustrated as beginning with a contacting operation <NUM>. In the contacting operation <NUM> a carbonaceous feedstock is maintained in contact with supercritical carbon dioxide for some contact period at a pyrolysis temperature and pressure sufficient to both maintain the CO<NUM> in a supercritical state and at which pyrolysis occurs. The resulting pyrolysis causes at least some of the feedstock to be converted into char and generates some amount of pyrolysis reaction products which are dissolved into the CO<NUM>.

The contact period, or residence time, used may be selected by the operator. The contacting may be static in that the CO<NUM> is not flowing through the contacting chamber during the pyrolysis. Rather, the chamber is charged with CO<NUM> and the feedstock and then allowed to react, with or without internal agitation or other mixing. In this case, the contact time is the time that the CO<NUM> is supercritical and within the contacting chamber with the feedstock. Alternatively, the contacting may be dynamic in that the CO<NUM> is constantly flowing through the chamber containing the feedstock. In the dynamic contacting, the residence time is calculated from the flowrate of CO<NUM> and the volume of the contacting chamber.

The chemical makeup of the pyrolysis reaction products can varied to a certain extent by changing the pyrolysis conditions. For example, a relatively higher temperature and pressure used in the contacting operation <NUM> may favor the generation of some reaction products (e.g., heavier hydrocarbons such as oils) over others (e.g., mid-weight oils or lighter hydrocarbon gases). In addition, additives such as water, formic acid, hydrogen, or some other hydrogen donor may be used to increase the availability of hydrogen during the pyrolysis, which will also change the chemical
makeup of the reaction products. Other additives may also be used to affect the pyrolysis reaction and vary the chemical makeup of the reaction products.

After the contact time, the supercritical CO<NUM>, now containing dissolved pyrolysis reaction products, is separated from the char in a separation operation <NUM>. The separation operation may take the form of removing the char from the CO<NUM> or removing the CO<NUM> from the char.

After the separation operation <NUM>, the supercritical CO<NUM> is then cooled in a first cooling operation <NUM> to a first temperature and a first pressure. For example, the pyrolysis temperature and pressure is <NUM> and <NUM> MPa, respectively, and the first temperature and first pressure is <NUM> and <NUM> MPa. The first cooling operation <NUM> may include reducing the temperature or the temperature and the pressure of the CO<NUM> from the pyrolysis temperature and pressure used in the contacting operation <NUM>. In addition, although referred to as the cooling operation <NUM> the 'cooling' may consist of only reducing the pressure of the CO<NUM> while maintaining the temperature at or close to the pyrolysis temperature. Regardless of whether the temperature, the pressure or both are reduced, the cooling operation <NUM> causes the solubility of the dissolved reaction products to change and any reaction products that are no longer soluble in the CO<NUM> and the first temperature and pressure will condense out of the CO<NUM> as a condensate.

As part of or after the first cooling operation <NUM>, the condensate generated by the first cooling operation <NUM> may be collected and stored for later use. Contents of this condensate will be determined by the reaction products generated by the pyrolysis reaction and the first temperature and pressure of the first cooling operation <NUM>. Thus, as described above, through selection of the first temperature and pressure, the chemical makeup of the condensate generated by the first cooling operation <NUM> can be controlled to obtain a specific fraction of the pyrolysis reaction products. Once the temperatures are known, the heat exchanger equations can be used to determine the relative flow rates of the return stream and process stream through the different recuperators necessary to achieve those temperatures and, thus, the desired condensate. From this information the controller can then set the positions of the bypass valves as necessary to obtain the determined flow rates.

The CO<NUM> with the remaining reaction products is then subjected to a second cooling operation <NUM>. Similar to the first cooling operation <NUM>, the second cooling operation <NUM> reduces the CO<NUM> from the first temperature and pressure to a second temperature and pressure. Again, this may include reducing the temperature, the pressure or both of the CO<NUM>. The second cooling operation can be performed using the same equipment as the first cooling operation <NUM> or by passing the CO<NUM> to a second set of equipment (e.g., heat exchanger, cooling vessel, etc.) in which the second cooling operation is performed.

As part of or after the second cooling operation <NUM>, the condensate generated by the second cooling operation <NUM> may be collected and stored for later use. Contents of this second condensate will be determined by the reaction products generated by the pyrolysis reaction, the first temperature and pressure used in first cooling operation <NUM>, and the second temperature and pressure of the second cooling operation <NUM>. Thus, as described above, through selection of the first and second temperatures and pressures, the chemical makeup of the condensate generated by the second cooling operation <NUM> can be controlled to obtain a specific fraction of the pyrolysis reaction products. Once the temperatures are known, the heat exchanger equations can be used to determine the relative flow rates of the return stream and process stream through the different recuperators necessary to achieve those temperatures and, thus, the desired condensate. From this information the controller can then set the positions of the bypass valves as necessary to obtain the determined flow rates.

Additional cooling operations (not shown) can be performed. By using additional cooling operations the fractionation and collection of the reaction products can be tightly controlled. For example, <NUM> cooling operations can be used to obtain very finely fractionated condensates. Any number of cooling operations may be used as desired depending on the operator's goals. With reference to <FIG> that shows a system with a potential of five cooling operations, the chemical makeup of the condensates of each of the five stages can be varied by changing the relative temperatures and pressures of the operations. For example, in one configuration, the first four cooling operations may be done with very narrow temperature and/or pressure differences - e.g., the first temperature may be <NUM> less than the pyrolysis temperature, the second temperature <NUM> less, the third <NUM> less and the fourth <NUM> less, while the last temperature may be <NUM>, a configuration that would fractionating higher temperature reaction products (that is, reaction products that condense out of the CO<NUM> at a higher temperature). In another configuration, the temperature differences may be more even between stages and in yet another configuration the temperatures may be focused to fractionate lower temperature products. Thus, as part of this method, the temperatures and pressures of the different cooling operations may be controlled to obtain specific desired fractions of the reaction products.

Finally the CO<NUM> is recycled and reused for additional pyrolysis is a reuse operation <NUM>. The reuse may be done in a continuous system in which the CO<NUM> is continuously flowing in a loop such as that shown in <FIG>. Alternatively, the CO<NUM> may be stored for reuse later in a batch or semi-batch system.

As part of the method <NUM>, the CO<NUM> may be maintained in the supercritical state throughout the entire method. Alternatively, the CO<NUM> may be taken to a subcritical state, for example in a final cooling operation, in order to condense and remove as much of the reaction products as possible, before the CO<NUM> is returned to the supercritical state in the reuse operation <NUM>.

<FIG> is a more detailed method for pyrolyzing coal with supercritical CO<NUM>. While the method <NUM> of <FIG> is more broadly written to cover any batch, semi-batch or continuous pyrolysis process, the method <NUM> of <FIG> is more specific to a continuous pyrolysis process that fractionates pyrolysis products from coal and recycles the CO<NUM> in a continuously flowing loop.

As shown in <FIG>, the method <NUM> begins with flowing an inlet stream of carbon dioxide (CO<NUM>) into a reaction chamber containing coal in a supercritical CO<NUM> injection operation <NUM>. The inlet CO<NUM> stream's temperature may be from <NUM>-<NUM> and pressure is from <NUM>-<NUM> MPa.

The reaction chamber is maintained at a pyrolysis temperature and pressure sufficient to maintain the CO<NUM> in the reaction chamber in a supercritical state. This is illustrated in <FIG> by the pyrolysis operation <NUM>. The pyrolysis operation <NUM> may include actively controlling the temperature and pressure of the reaction chamber. For example, an internal or external heater may be used to add heat directly to the reaction chamber to control its temperature. Likewise, the pressure may be controlled by adjusting the flow rate of the inlet and outlet CO<NUM> streams. Alternatively, the temperature and pressure of the reaction chamber may be indirectly controlled solely by controlling the temperature and flow rate of the inlet stream. Thus, the coal is pyrolyzed to obtain a char and supercritical CO<NUM> containing dissolved pyrolysis products in the pyrolysis operation <NUM>. As discussed above with reference to <FIG>, the chemical makeup of the reaction products may be controlled to an extent by changing the temperature and pressure in the reaction chamber and also through the use of certain additives.

After a contact period determined by the CO<NUM> flow rate through the reaction chamber and the volume of CO<NUM> in the chamber, the supercritical CO<NUM> containing dissolved pyrolysis products then flows as a reactor outlet stream from the reaction chamber via an outlet in an outlet stream discharge operation <NUM>.

The outlet stream is then passed to first recuperator in a first recuperation and collection operation 706a. In this operation 706a, the reactor outlet stream is cooled in the first recuperator by transferring heat to a return stream of CO<NUM> on its way back to the reaction chamber. The outlet stream is cooled to a first temperature less than the pyrolysis reaction temperature based on the temperatures and flow rates of the two CO<NUM> streams, i.e., the outlet stream and the return stream, passing through the first recuperator.

The act of cooling the outlet stream causes the dissolved reaction products which condense at temperatures greater than the first temperature, if any, in the outlet stream to condense out of the CO<NUM>. The first recuperation and collection operation 706a includes collecting this first stage condensate in a collector such as a collection vessel as shown in <FIG>. It also includes discharging a first stage CO<NUM> effluent stream that contains any dissolved reaction products not removed as a first stage condensate.

It should be pointed out that not all of the outlet stream may be treated in the first recuperation and collection operation 706a. Some portion of the outlet stream may be sent to a later stage recuperator and treated in a later recuperation and collection operation. This diversion of some of the outlet stream may be done to control the chemical makeup of the condensates obtained from the different stages.

The first stage CO<NUM> effluent stream is then passed to second recuperator in a second recuperation and collection operation 706b. In this operation 706b, the reactor first stage CO<NUM> effluent stream is cooled in the second recuperator by transferring heat to the return stream of CO<NUM> on its way back to the reaction chamber. The first stage CO<NUM> effluent stream is cooled to a second temperature less than the first temperature based on the temperatures and flow rates of the two CO<NUM> streams, i.e., the first stage CO<NUM> effluent stream and the return stream, passing through the second recuperator.

Again, the act of cooling the outlet stream causes those dissolved reaction products remaining in the first stage CO<NUM> effluent stream which condense at temperatures higher than the second temperature, if any, to condense out of the CO<NUM>. The second recuperation and collection operation 706b includes collecting this second stage condensate in a collector such as a collection vessel as shown in <FIG>. It also includes discharging a second stage CO<NUM> effluent stream that contains any remaining dissolved reaction products not removed as a second stage condensate.

Again, not all of the first stage CO<NUM> effluent stream need be passed to the second recuperator and some portion of the first stage CO<NUM> effluent stream may be diverted to a later recuperation and collection operation in order to change the chemical makeup of later stage condensates.

Any number of additional recuperation and collection operations may be performed in the method <NUM>. This is illustrated in <FIG> by the ellipsis and the n-stage recuperation and collection operation 706n. Each of the recuperation and collection operations 706a-n may be identical except for the operational temperature and pressures of the two CO<NUM> streams involved. The condensates recovered from each of the operations 706a-n may be controlled by diverting portions of the process stream and/or return stream around and to various operations 706a-n to obtain desired condensates. The distribution of flow through the different recuperation and collection operation 706a-n may be manually controlled or automatically controlled by a controller in order to collect different fractions at different stages as described above.

Note that one or more of the operations 706a-n, such as for example the final recuperation and collection operation 706n as in <FIG>, may not include recuperating heat from the process stream. That is, rather than passing heat to the return stream of CO<NUM> and effectively recycling that energy, the heat may simply be removed, such as by transferring it to a cold water stream, and either discarded or recycled for another purpose.

In addition, not all of the recuperation and collection operations 706an need include the collection of a condensate in a separate vessel. Rather, some condensates could be directed into the following stage recuperators for later collection in a downstream recuperation and collection operation.

After the last recuperation and collection operations 706n, the final stage CO<NUM> effluent steam is then reconditioned by passing it as the return stream through the various recuperation stages in a reconditioning operation <NUM>. The reconditioning operation <NUM> may include compressing the return stream and/or heating the return stream at one or more points in the system's CO<NUM> return circuit. For example, in <FIG> the return stream is compressed by the pump <NUM> right after the fifth recuperation and collection operation (in that case not a true recuperation as the heat is removed using a cold water stream) and heated by heater <NUM> just prior to being injected into the reaction chamber <NUM>.

Note that the reconditioning operation <NUM> may or may not clean any remaining reaction products from the CO<NUM>. Some trace amounts of reaction products and/or other compounds such as water remain in the CO<NUM> return stream when it is injected into the reaction chamber.

Claim 1:
A system (<NUM>) for manufacturing fibers from coal comprising:
at least one reaction chamber (<NUM>) capable of pyrolyzing a combination of coal (<NUM>) in a carbon dioxide atmosphere;
a heat source (<NUM>) configured to provide thermal energy to the reaction chamber;
a separation system (<NUM>) configured to receive the carbon dioxide atmosphere from a first outlet (<NUM>) of the reaction chamber after pyrolysis of the coal and condense pitch from the carbon dioxide into a pitch container;
a thermal energy transfer system (<NUM>) configured to transfer thermal energy from the heat source to the reaction chamber, the thermal energy transfer system comprising a heat transfer element (<NUM>) including a heat transfer loop filled with a supercritical fluid and in thermal communication with the heat source;
a flow control system (<NUM>) positioned along the heat transfer element and configured to control the flow of supercritical fluid through the heat transfer element;
a feedstock supply system (<NUM>) operable coupled to the reaction chamber and configured to provide the coal and water to an interior of the reaction chamber;
a residual storage system (<NUM>) configured receive feedstock residue from a second outlet (<NUM>) of the reaction chamber;
a product collection system (<NUM>) configured to collect the other compounds from the separation system;
a return path (<NUM>) configured to circulate the carbon dioxide from the separation system back to the heat source; and
an extruder (<NUM>) connected to the separation system configured to receive and extrude the pitch condensed by the separation system.