TECHNICAL FIELD

This disclosure relates generally to biochar cooling.

BACKGROUND

Decarbonization of the energy sector is a topic of importance to avoid irreversible global warming. Hydrogen has been considered as an option to replace fossil fuels in industrial, residential, and transport applications. However, hydrogen production has been almost limited to the reforming of hydrocarbons. Reforming hydrocarbons may release large amounts of CO2, thus requiring several downstream purification processes.

Gasification is a thermal decomposition process in which solid organic or carbonaceous materials (feedstock) may break down into a combustible gas mixture. The combustible gas components formed are primarily carbon monoxide (CO), hydrogen (H2), and methane (CH4). Other non-combustible gases such as nitrogen (N2), steam (H2O), and carbon dioxide (CO2) may also be present in various quantities. The process of gasification may involve pyrolysis followed by partial oxidation, which may be controlled by injecting air or other oxygen containing gases into the partially pyrolyzed feedstock. More specifically, biomass gasification may be a sequence of reactions including water evaporation, lignin decomposition, cellulosic deflagration and carbon reduction. An external heat source may begin the reaction, but partial oxidation may provide heat to maintain the thermal decomposition of the feedstock. If concentrated oxygen is used, the resulting gas mixture may be called syngas. If air (which includes nitrogen) is used as the oxidant, the resulting gas mixture may be called producer gas. For simplicity, the term “Producer Gas” as used herein shall include both syngas and producer gas. Both gas mixtures are considered a “fuel gas” and can be used as a replacement for natural gas in some processes. They can also be used as a precursor to generate various industrial chemicals and motor fuels. When biomass is used as the feedstock, gasification and combustion of the Producer Gas is considered to be a source of renewable energy.

As a general matter, gasification offers a more efficient, cost effective and environmentally friendly alternative for extracting potential energy from solid feedstock as compared to combustion. As a result of gasification, the feedstock's potential energy can be converted to Producer Gas, which is cleaner burning, compressible and more portable. Producer Gas may be burned directly in some engines and burners, purified to produce methanol and hydrogen, or converted via the Fischer-Tropsch and other methods and processes into synthetic liquid fuel.

In general, biomass gasification is the thermochemical conversion of organic (waste) feedstock in a high-temperature environment, through which biomass may be converted not only to syngas for energy generation but also to chemicals, for instance, methane, ethylene, adhesives, fatty acids, surfactants, detergents, and plasticizers. A byproduct of biomass gasification is hot biochar.

The present disclosure relates to direct cooling of biochar resulting from gasification by downdraft and fluidized bed gasifiers. Brief downdraft and fluidized bed gasification descriptions and simple examples of downdraft and fluidized bed gasifiers are provided. Exemplary downdraft gasification may be implemented using downdraft gasification techniques disclosed with reference to FIGS. 1-21 of U.S. Pat. No. 10,662,386 by Kelfkens, et al., filed on Dec. 6, 2019 as U.S. patent application Ser. No. 16/705,837, and entitled “Method for gasifying feedstock with high yield production of biochar,” the entire contents of which are herein incorporated by reference. Exemplary fluidized bed gasification may be implemented using fluidized bed gasification techniques disclosed with reference to FIGS. 1-8 of U.S. Pat. No. 10,696,913 by Kelfkens, et al., filed on Dec. 20, 2019 as U.S. patent application Ser. No. 16/723,538, and entitled “Gasification reactor with pipe distributor,” the entire contents of which are herein incorporated by reference.

Downdraft Gasification

In downdraft gasification, all feedstock, air and gases flow in the same direction—from top to bottom. Although updraft gasification is typically favored for processing of biomass feedstock and fluid bed gasification is typically used in gasification of coal, downdraft gasification process has a number of advantages. One advantage of downdraft gasification is low levels of tar in the resulting Producer Gas because the tars generated during pyrolysis must pass through the Oxidation Zone and the char bed in the Reduction Zone before exiting the gasifier. The high temperature of the Oxidation Zone and the top of the char bed breaks down the tars (i.e., thermal cracking). The result is a Producer Gas that may be cooled and more easily cleaned for use in reciprocating engines, gas-fired turbines and catalytic reforming processes.

In an exemplary downdraft gasifier implementation, there may be three zones: a Pyrolysis Zone, an Oxidation Zone and a Reduction Zone. In such a gasifier, (1) the residence time of feedstock could be controlled in the Oxidation Zone (relative to the flow of feedstock through the rest of the gasifier) to allow the maximum amount of feedstock to undergo gasification before passing out of the Oxidation Zone into the Reduction Zone and (2) the Reduction Zone would be designed to cause the hot gas produced in the Oxidation Zone to mix with the char in the Reduction Zone as quickly and as thoroughly as possible to promote thorough gasification.

Fluidized-Bed Gasification

In an exemplary fluidized-bed gasifier implementation, oxidant may be blown through a bed of solid particles at a sufficient velocity to keep the solid particles in a state of suspension. The feedstock is introduced to the gasifier, very quickly mixed with the bed material and almost instantaneously heated to the bed temperature either externally or using a heat transfer medium. Most of these fluidized-bed gasifiers are equipped with an internal cyclone in order to minimize char (carried over into the Producer Gas stream) and remove fluidizing media from the Producer Gas. The major advantages include feedstock flexibility and the ability to easily control the reaction temperature, which allows for gasification of fine grained materials (sawdust, etc.) without the need of pre-processing. Fluidized-bed gasifiers also scale very well to large sizes.

In various exemplary gasification scenarios, hot carbonaceous residue may come off or through the grate of a downdraft gasifier, off the bottom of a cyclone, or off the bottom of a cyclone in association with a fluidized bed gasifier. Both downdraft and fluidized bed gasifier systems may employ an expensive indirect cooling approach to create a cool biochar that may not be resizable (Grinder) based on product demand by a gasifier system using indirect cooling.

Some prior art biochar cooling implementations may indirectly utilize heated steam to run over biochar to improve the biochar's compositional characteristics. These prior art biochar cooling processes may heat steam to extremely high temperatures to react with ambient temperature biochar. Some prior art biochar cooling implementations may indirectly utilize heated hydrocarbon gas run over biochar to improve compositional characteristics and decompose methane. These prior art biochar cooling processes may heat hydrocarbon gas streams to extremely high temperatures to react with the ambient temperature biochar.

In an illustrative example, the composition of biochar product from a gasifier employing indirect cooling may not be useful in high value applications, such as, for example, as an alternative to activated carbon. In addition, the biochar product from a gasifier employing indirect cooling may not be useful in production of high purity carbon for manufacturing purposes, such as, for example, graphene.

SUMMARY

Apparatus and associated methods relate to cooling hot biochar based on applying cool gas directly to the hot biochar. The gas may be steam comprising water vapor. Biochar may be cooled in a cooling chamber by cool steam injected into a steam loop configured to cool the steam. The biochar cooled with steam may be dried in a drying chamber by dry gas injected from a gas loop. The gas may be hydrocarbon gas. Biochar may be heated in a processing chamber. Heated biochar may be cooled in a cooling chamber by cool hydrocarbon gas injected to the cooling chamber. Biochar in the processing chamber may be heated with heat recovered from cooling. Filtered byproducts and tail gas may be recovered from the cooling chamber. Tail gas may be recycled. Various direct biochar cooling implementations may produce biochar having enhanced carbon content, increased surface area, and a hydrogen stream byproduct.

In an aspect, an apparatus may comprise: a cooling chamber; a steam loop configured to be fluidly coupled with the cooling chamber; a drying chamber configured to be fluidly coupled with the cooling chamber; a gas loop configured to be fluidly coupled with the drying chamber; and a control system configured to cause the apparatus to perform operations comprising: inject cool steam from the steam loop into the cooling chamber; apply the cool steam directly to hot biochar retained within the cooling chamber; and in response to a determination the biochar retained within the cooling chamber cooled to a predetermined temperature: discharge the cooled biochar into the drying chamber; inject dry gas from the gas loop into the drying chamber; and in response to a determination the biochar retained within the drying chamber dried to a predetermined moisture level, discharge the cooled dried biochar from the drying chamber.

The apparatus may further comprise the cooling chamber configured to receive hot biochar via at least one discharge valve configured to be fluidly coupled with the cooling chamber.

The operations performed by the apparatus may further comprise receive hot biochar into the cooling chamber via at least one discharge valve fluidly coupled with the cooling chamber.

Receive hot biochar may further comprise receive hot biochar from a gasifier fluidly coupled with the apparatus.

The gasifier may further comprise a downdraft gasifier.

The gasifier may further comprise a fluidized bed gasifier.

The steam loop may further comprise a heat exchanger.

The gas loop may further comprise a particulate filter.

The apparatus may further comprise at least one discharge valve configured to fluidly couple the cooling chamber to the drying chamber.

In an implementation, an apparatus may comprise: a cooling chamber; at least one discharge valve configured to be fluidly coupled with the cooling chamber, wherein the at least one discharge valve is configured to be fluidly coupled with a gasifier to direct hot biochar from the gasifier into the cooling chamber; a steam loop configured to be fluidly coupled with the cooling chamber, wherein the steam loop is configured with a steam particulate filter and a heat exchanger; a drying chamber configured to be fluidly coupled with the cooling chamber by at least one discharge valve configured to direct biochar from the cooling chamber into the drying chamber; a gas loop configured to be fluidly coupled with the drying chamber, wherein the gas loop is configured with a gas particulate filter and a heat exchanger; at least one discharge valve configured to be fluidly coupled with the drying chamber, wherein the at least one discharge valve is configured to release biochar from the drying chamber; and a control system configured to cause the apparatus to perform operations comprising: receive hot biochar from the gasifier into the cooling chamber; inject cool steam from the steam loop into the cooling chamber; apply the cool steam directly to the hot biochar retained within the cooling chamber; and in response to a determination the biochar retained within the cooling chamber cooled to a predetermined temperature: discharge the cooled biochar into the drying chamber; inject dry gas from the gas loop into the drying chamber; and in response to a determination the biochar retained within the drying chamber dried to a predetermined moisture level, release the cooled dried biochar from the drying chamber.

The gasifier may further comprise a downdraft gasifier.

The gasifier may further comprise a fluidized bed gasifier.

The cooling chamber may be fluidly coupled with the gasifier.

The steam particulate filter may further comprise a ceramic filter.

The gas particulate filter may further comprise a sintered metal filter.

The apparatus may further comprise stainless steel.

In an implementation, an apparatus may comprise: a cooling chamber configured with a gas inlet, a biochar inlet, a biochar outlet, and a gas outlet; at least one discharge valve configured to be fluidly coupled with the cooling chamber biochar inlet, wherein the at least one discharge valve is configured to be fluidly coupled with a gasifier to direct hot biochar from the gasifier into the cooling chamber; a steam loop configured to be fluidly coupled with the cooling chamber gas inlet and the cooling chamber gas outlet, wherein the steam loop comprises a steam makeup port fluidly coupled with the steam loop; a steam particulate filter configured with an inlet and a filtered outlet, wherein the steam particulate filter inlet is fluidly coupled with the cooling chamber gas outlet, and wherein the steam particulate filter outlet is fluidly coupled with the steam loop; a heat exchanger configured in the steam loop, wherein the heat exchanger comprises a steam to liquid heat exchanger; a drying chamber configured with a gas inlet, a biochar inlet, a biochar outlet, and a gas outlet, wherein the drying chamber biochar inlet is configured to be fluidly coupled with the cooling chamber biochar outlet by at least one discharge valve configured to direct biochar from the cooling chamber into the drying chamber; a gas loop configured to be fluidly coupled with the drying chamber gas inlet and the drying chamber gas outlet, wherein the gas loop comprises a gas makeup port fluidly coupled with the gas loop; a gas particulate filter configured with an inlet and a filtered outlet, wherein the gas particulate filter inlet is fluidly coupled with the drying chamber gas outlet, and wherein the gas particulate filter outlet is fluidly coupled with the gas loop; a heat exchanger configured in the gas loop, wherein the heat exchanger comprises a gas to liquid or gas to gas heat exchanger; and a control system configured to cause the apparatus to perform operations comprising: receive hot biochar from the gasifier into the cooling chamber; inject cool steam from the steam loop into the cooling chamber gas inlet; apply the cool steam directly to hot biochar retained within the cooling chamber; and in response to a determination the biochar retained within the cooling chamber cooled to a predetermined temperature: discharge the cooled biochar into the drying chamber; inject dry gas from the gas loop into the drying chamber; and in response to a determination the biochar retained within the drying chamber dried to a predetermined moisture level, release the cooled dried biochar from the drying chamber.

The apparatus may further comprise a biochar recovery system fluidly coupled with the drying chamber biochar outlet, and wherein release the cooled dried biochar from the drying chamber further comprises release the cooled dried biochar into the biochar recovery system.

The operations performed by the apparatus may further comprise inject cool steam into the steam loop steam makeup port.

The operations performed by the apparatus may further comprise inject dry gas into the gas loop gas makeup port.

In another aspect, an apparatus may comprise: a processing chamber; a heat source thermally coupled with the processing chamber; a cooling chamber configured to be fluidly coupled with the processing chamber; and a control system configured to cause the apparatus to perform operations comprising: heat biochar retained within the processing chamber; and in response to a determination the biochar retained within the processing chamber heated to a predetermined temperature: discharge the hot biochar into the cooling chamber; inject cool gas into the cooling chamber; apply the cool gas directly to the hot biochar retained within the cooling chamber; and in response to a determination the biochar retained within the cooling chamber cooled to a predetermined temperature, discharge the cooled biochar from the cooling chamber.

The processing chamber may be configured to receive biochar via at least one discharge valve configured to be fluidly coupled with the processing chamber.

The operations performed by the apparatus may further comprise receive biochar into the processing chamber via at least one discharge valve fluidly coupled with the processing chamber.

Receive biochar may further comprise receive biochar from a gasifier fluidly coupled with the apparatus.

The gasifier may further comprise a downdraft gasifier.

The gasifier may further comprise a fluidized bed gasifier.

The heat source may further comprise a heating element.

The heat source may further comprise process heat.

The apparatus may further comprise at least one discharge valve configured to fluidly couple the processing chamber to the cooling chamber.

In an implementation, an apparatus may comprise: a processing chamber; at least one discharge valve configured to be fluidly coupled with the processing chamber, wherein the at least one discharge valve is configured to be fluidly coupled with a gasifier to direct biochar from the gasifier into the processing chamber; a heat source thermally coupled with the processing chamber, wherein the heat source comprises a heating element; a cooling chamber configured to be fluidly coupled with the processing chamber by at least one discharge valve configured to direct biochar from the processing chamber into the cooling chamber, wherein the cooling chamber includes a gas inlet port, and wherein the cooling chamber includes a gas outlet configured to be fluidly coupled with a particulate filter by a discharge valve; a CO2removal filter having an inlet, a CO2outlet, and a mixed gas outlet, wherein the CO2removal filter inlet is fluidly coupled with the particulate filter; an H2removal filter having an inlet, an H2outlet, and a mixed gas outlet, wherein the H2removal filter inlet is fluidly coupled with the CO2removal filter mixed gas outlet; at least one discharge valve configured to be fluidly coupled with the cooling chamber, wherein the at least one discharge valve is configured to release biochar from the cooling chamber; and a control system configured to cause the apparatus to perform operations comprising: heat biochar retained within the processing chamber, using the heat source; and in response to a determination the biochar retained within the processing chamber heated to a predetermined temperature: discharge the hot biochar into the cooling chamber; inject cool gas comprising hydrocarbon into the cooling chamber through the cooling chamber gas inlet port; apply the cool hydrocarbon gas directly to the hot biochar retained within the cooling chamber; and in response to a determination the biochar retained within the cooling chamber cooled to a predetermined temperature: release the cooled biochar from the cooling chamber; and release the hydrocarbon gas into the particulate filter through the cooling chamber gas outlet.

The gasifier may further comprise a downdraft gasifier.

The gasifier may further comprise a fluidized bed gasifier.

The processing chamber may be fluidly coupled with the gasifier.

The apparatus may further comprise a thermal oxidizer thermally coupled with the processing chamber, and a tail gas recycle loop fluidly coupled with the H2removal filter mixed gas output and the thermal oxidizer.

The tail gas recycle loop may be fluidly coupled with the cooling chamber gas inlet port.

The apparatus may further comprise a biochar recovery system and the operations performed by the apparatus further comprise release the cooled biochar into the biochar recovery system.

In an implementation, an apparatus may comprise: a processing chamber; at least one discharge valve configured to be fluidly coupled with the processing chamber, wherein the at least one discharge valve is fluidly coupled with a gasifier to direct biochar from the gasifier into the processing chamber; a cooling chamber configured to be fluidly coupled with the processing chamber by at least one discharge valve configured to direct biochar from the processing chamber into the cooling chamber, wherein the cooling chamber includes a gas inlet port, and wherein the cooling chamber includes a gas outlet configured to be fluidly coupled with a particulate filter by a discharge valve; a CO2removal filter having an inlet, a CO2outlet, and a mixed gas outlet, wherein the CO2removal filter inlet is fluidly coupled with the particulate filter; an H2removal filter having an inlet, an H2outlet, and a mixed gas outlet, wherein the H2removal filter inlet is fluidly coupled with the CO2removal filter mixed gas outlet; a thermal oxidizer thermally coupled with the processing chamber, and a tail gas recycle loop fluidly coupled with the H2removal filter mixed gas output and the thermal oxidizer, wherein the tail gas recycle loop is fluidly coupled with the cooling chamber gas inlet port; a heat source thermally coupled with the processing chamber, wherein the heat source comprises heat from the thermal oxidizer; at least one discharge valve configured to be fluidly coupled with the cooling chamber, wherein the at least one discharge valve is configured to release biochar from the cooling chamber; and a control system configured to cause the apparatus to perform operations comprising: heat biochar retained within the processing chamber, using the heat source; and in response to a determination the biochar retained within the processing chamber heated to a predetermined temperature: discharge the hot biochar into the cooling chamber; inject cool gas comprising hydrocarbon into the cooling chamber through the cooling chamber gas inlet port; apply the cool hydrocarbon gas directly to the hot biochar retained within the cooling chamber; in response to a determination the biochar retained within the cooling chamber cooled to a predetermined temperature: release the cooled biochar from the cooling chamber; and release the hydrocarbon gas through the cooling chamber gas outlet into the particulate filter.

The apparatus may further comprise a biochar recovery system and the operations performed by the apparatus further comprise release the cooled biochar into the biochar recovery system.

The apparatus may further comprise a tail gas recovery system fluidly coupled with the H2removal filter mixed gas outlet.

The apparatus may further comprise an H2gas recovery system fluidly coupled with the H2removal filter H2outlet.

In an aspect, a method may comprise: injecting cool steam into a cooling chamber; applying the cool steam directly to hot biochar retained within the cooling chamber; and in response to a determining the biochar retained within the cooling chamber cooled to a predetermined temperature: discharging the cooled biochar into a drying chamber; injecting dry gas into the drying chamber; and in response to determining the biochar retained within the drying chamber dried to a predetermined moisture level, discharging the cooled dried biochar from the drying chamber.

Injecting cool steam may further comprise injecting steam from a steam loop configured to cool steam.

The steam loop may further comprise a heat exchanger.

The method may further comprise receiving hot biochar into the cooling chamber.

Receiving hot biochar may further comprise receiving hot biochar from a gasifier.

The gasifier may further comprise a downdraft gasifier.

The gasifier may further comprise a fluidized bed gasifier.

Injecting dry gas may further comprise injecting gas from a gas loop configured to dry gas.

The gas loop may further comprise a particulate filter and a heat exchanger.

In an implementation, a method may comprise: receiving hot biochar from a gasifier into a cooling chamber; injecting cool steam from a steam loop into the cooling chamber, wherein the steam loop is configured with a steam particulate filter and a heat exchanger comprising a heat sink; applying the cool steam directly to the hot biochar retained within the cooling chamber; and in response to determining the biochar retained within the cooling chamber cooled to a predetermined temperature: discharging the cooled biochar into a drying chamber; injecting dry gas from a gas loop into the drying chamber, wherein the gas loop is configured with a gas particulate filter and a heat exchanger comprising a heat sink; and in response to determining the biochar retained within the drying chamber dried to a predetermined moisture level, releasing the cooled dried biochar from the drying chamber.

The gasifier may further comprise a downdraft gasifier.

The gasifier may further comprise a fluidized bed gasifier.

The steam particulate filter may further comprise a ceramic filter.

The steam particulate filter may further comprise a sintered metal filter.

The gas particulate filter may further comprise a ceramic filter.

The gas particulate filter may further comprise a sintered metal filter.

In an implementation, a method may comprise: receiving hot biochar from a gasifier into a cooling chamber through a discharge valve; injecting cool steam from a steam loop into the cooling chamber; applying the cool steam directly to hot biochar retained within the cooling chamber; and in response to determining, by a control system, the biochar retained within the cooling chamber cooled to a predetermined temperature: discharging, by the control system, the cooled biochar through a discharge valve into a drying chamber; injecting dry gas from a gas loop into the drying chamber; and in response to determining, by the control system, the biochar retained within the drying chamber dried to a predetermined moisture level, releasing, by the control system, the cooled dried biochar from the drying chamber through a discharge valve.

Releasing the cooled dried biochar from the drying chamber may further comprise releasing the cooled dried biochar into a biochar recovery system.

The method may further comprise injecting cool steam into a steam makeup port fluidly coupled with the steam loop.

The method may further comprise injecting dry gas into a gas makeup port fluidly coupled with the gas loop.

In another aspect, a method may comprise: heating biochar retained within a processing chamber, using a heat source thermally coupled with the processing chamber; and in response to determining the biochar retained within the processing chamber heated to at least a predetermined temperature: discharging the heated biochar into a cooling chamber; injecting cool gas into the cooling chamber; applying the cool gas directly to the biochar retained within the cooling chamber; and in response to determining the biochar retained within the cooling chamber cooled to a predetermined temperature, discharging the cooled biochar from the cooling chamber.

The method may further comprise receiving biochar into the processing chamber.

The method may further comprise receiving biochar from a gasifier into the processing chamber, and retaining the biochar within the processing chamber.

The gasifier may further comprise a downdraft gasifier.

The gasifier may further comprise a fluidized bed gasifier.

The heat source may further comprise a heating element.

The heat source may further comprise process heat, and the method may further comprise: in response to determining the process heat is at least a predetermined minimum temperature, deactivating the heating element.

Discharging the heated biochar into the cooling chamber may further comprise fluidly coupling the processing chamber to the cooling chamber.

The method may further comprise retaining the biochar within the processing chamber for at least a predetermined time period.

In an implementation, a method may comprise: receiving biochar into a processing chamber configured to be fluidly coupled with a gasifier; heating the biochar retained within the processing chamber, using a heat source thermally coupled with the processing chamber, wherein the heat source comprises a heating element and process heat; and in response to determining the biochar retained within the processing chamber heated to a predetermined temperature: discharging the heated biochar into a cooling chamber; injecting cool gas comprising hydrocarbon into the cooling chamber; applying the cool gas comprising hydrocarbon directly to the biochar retained within the cooling chamber; and in response to determining the biochar retained within the cooling chamber cooled to a predetermined temperature: releasing the cooled biochar from the cooling chamber; and releasing gas from the cooling chamber into a particulate filter fluidly coupled with the cooling chamber.

The gasifier may further comprise a downdraft gasifier.

The gasifier may further comprise a fluidized bed gasifier.

The gasifier may be fluidly coupled with the processing chamber.

The method may further comprise recovering carbon dioxide from a CO2removal filter fluidly coupled with the particulate filter.

The method may further comprise recovering hydrogen from an H2removal filter fluidly coupled with the particulate filter.

The method may further comprise recycling tail gas as cooling gas supplied to the cooling chamber through a tail gas recycle loop fluidly coupled with the H2removal filter and the cooling chamber.

The method may further comprise heating the biochar retained within the processing chamber using process heat comprising heat generated by a thermal oxidizer from tail gas, wherein the thermal oxidizer is thermally coupled with the processing chamber.

The method may further comprise supplying the tail gas to the thermal oxidizer from an H2removal filter fluidly coupled with the particulate filter.

In an aspect, a method may comprise: receiving biochar from a gasifier into a processing chamber; heating biochar retained within the processing chamber, using a heat source thermally coupled with the processing chamber, wherein the heat source comprises a heating element and recovered process heat from a thermal oxidizer supplied with tail gas; in response to a determination, by a control system, the process heat is at least a predetermined minimum temperature, deactivating, by the control system, the heating element; and in response to determining, by a control system, the biochar retained within the processing chamber heated to at least a predetermined minimum temperature: discharging the biochar into a cooling chamber; injecting cool gas into the cooling chamber; applying the cool gas directly to the biochar retained within the cooling chamber; and in response to a determining, by the control system, the biochar retained within the cooling chamber cooled to at least a predetermined maximum temperature: releasing the biochar from the cooling chamber; releasing gas from the cooling chamber into a particulate filter; recovering carbon dioxide from a CO2removal filter fluidly coupled with the particulate filter; recovering hydrogen from an H2removal filter fluidly coupled with the CO2removal filter; supplying tail gas recovered from the H2removal filter to the thermal oxidizer; heating the processing chamber using process heat comprising heat generated by the thermal oxidizer from the tail gas; and recycling a portion of the tail gas as cooling gas supplied to the cooling chamber.

The method may further comprise repeating the method with the heating element deactivated.

The method may further comprise releasing the biochar from the cooling chamber into a biochar recovery system.

Receiving biochar from the gasifier may further comprise receiving biochar from a plurality of gasifiers.

More than one gasifier of the plurality of gasifiers may be fluidly coupled with the processing chamber.

A direct biochar cooling implementation in accordance with the present disclosure may provide an alternative to an indirect biochar cooling design.

Various implementations in accordance with the present disclosure relate to a cost-effective means to cool hot biochar using direct application of cool gases comprising H2O or CH4. An exemplary direct cooling implementation in accordance with the present disclosure may decompose cooling gas comprising methane.

A co-effect of an exemplary direct cooling approach in accordance with the present disclosure may be that the cool gases comprising compounds which include CH4decompose into carbon, which may aggregate as additional solid carbon. Another co-effect may be that the physical and chemical composition of the biochar may be modified as a result of the application of the cooling gas, which may increase the surface area of the carbon and/or modify the carbon structures.

In one aspect of the present disclosure, direct cooling of hot biochar with steam as the hot biochar exits a gasifier or cyclone may create an economical way to cool biochar while enhancing the surface area of the biochar, resulting in a byproduct that is comparable to activated carbon.

In another aspect of the present disclosure, direct cooling of hot biochar with hydrocarbon gas as the hot biochar exits the gasifier or cyclone may create an economical way to cool biochar while enhancing the high-quality carbon content of the biochar with nano tube type carbon formation on the biochar [chemical vapor deposition], while producing a gas stream that may be filtered for high value chemical (such as, for example, hydrogen) recovery.

In an illustrative example, various implementations in accordance with the present disclosure may not use a formulated metal catalyst. To the extent metals are present in biochar produced by such implementations that do not use a formulated metal catalyst, the metals present in the biochar may derive from the natural presence of the metals in the biomass, or the metals' non-deliberate presence in the biosolids.

The present disclosure teaches direct biochar cooling.

Direct biochar cooling may be implemented as an apparatus. Direct biochar cooling may be implemented as a method.

The apparatus may comprise steam direct biochar cooling. The apparatus may comprise hydrocarbon gas direct biochar cooling. The apparatus may comprise hydrocarbon gas direct biochar cooling with tail gas recycling.

The steam direct biochar cooling apparatus comprises a cooling chamber. The steam direct biochar cooling apparatus comprises a drying chamber configured to be fluidly coupled with the cooling chamber. The cooling chamber comprises at least one inlet. The cooling chamber comprises at least one outlet. The drying chamber comprises at least one inlet. The drying chamber comprises at least one outlet. The apparatus may comprise a discharge valve configured to fluidly couple the cooling chamber with the drying chamber. The apparatus may comprise a flange configured to be fluidly coupled with the cooling chamber. The cooling chamber may be fluidly coupled with the flange by a discharge valve. The flange fluidly coupled with the cooling chamber may be configured to be fluidly coupled with a gasifier. The flange configured to be fluidly coupled with the gasifier may be fluidly coupled with the cooling chamber by a discharge valve. The apparatus may comprise at least one feed mechanism configured to be fluidly coupled with at least one discharge valve. The at least one feed mechanism may be configured to be fluidly coupled with the cooling chamber. The at least one feed mechanism may be configured to be fluidly coupled with the drying chamber. The apparatus comprises a steam loop fluidly coupled with the cooling chamber. The steam loop may be fluidly coupled with at least one cooling chamber outlet. The steam loop may be fluidly coupled with at least one cooling chamber inlet. The steam loop may comprise a particulate filter serially coupled with at least one cooling chamber outlet and at least one cooling chamber inlet. The steam loop may comprise a heat exchanger serially coupled with at least one cooling chamber outlet and at least one cooling chamber inlet. The heat exchanger may comprise a heat sink. The steam loop may comprise a steam inlet port. The apparatus comprises a gas loop fluidly coupled with the drying chamber. The gas loop may be fluidly coupled with at least one drying chamber outlet. The gas loop may be fluidly coupled with at least one drying chamber inlet. The gas loop may comprise a heat exchanger serially coupled with at least one drying chamber outlet and at least one drying chamber inlet. The heat exchanger may comprise a heat sink. The gas loop may comprise a gas inlet port. The gas loop may comprise a particulate filter serially coupled with at least one drying chamber outlet and at least one drying chamber inlet. The apparatus may comprise a flange configured to be fluidly coupled with the drying chamber. The drying chamber may be fluidly coupled with the flange by a discharge valve. The flange fluidly coupled with the drying chamber may be configured to be fluidly coupled with a biochar processing system. The apparatus may further comprise a control system configured to cool hot biochar. Cooling hot biochar may comprise operably couple one or more discharge valve and one or more feed mechanism to receive hot biochar in the cooling chamber, inject cool steam from the steam loop into the cooling chamber to cool the hot biochar, retain the cool steam and biochar in the cooling chamber until the biochar is cooled to a predetermined temperature, direct the cooled biochar into the drying chamber, inject dry gas from the gas loop into the drying chamber to dry the moist biochar, retain the dry gas and biochar in the drying chamber until the biochar is dried to a predetermined moisture level, and discharge the dried cooled biochar from the drying chamber.

The hydrocarbon gas direct biochar cooling apparatus comprises a processing chamber. The hydrocarbon gas direct biochar cooling apparatus comprises a cooling chamber configured to be fluidly coupled with the processing chamber. The processing chamber comprises at least one inlet. The processing chamber comprises at least one outlet. The cooling chamber comprises at least one inlet. The cooling chamber comprises at least one outlet. The apparatus may comprise a discharge valve configured to fluidly couple the processing chamber with the cooling chamber. The apparatus may comprise a flange configured to be fluidly coupled with the processing chamber. The processing chamber may be fluidly coupled with the flange by a discharge valve. The flange fluidly coupled with the processing chamber may be configured to be fluidly coupled with a gasifier. The flange configured to be fluidly coupled with the gasifier may be fluidly coupled with the processing chamber by a discharge valve. The apparatus may comprise at least one feed mechanism configured to be fluidly coupled with at least one discharge valve. The at least one feed mechanism may be configured to be fluidly coupled with the processing chamber. The at least one feed mechanism may be configured to be fluidly coupled with the cooling chamber. The apparatus may comprise a heating element thermally coupled with the processing chamber. The apparatus may comprise the processing chamber thermally coupled with process heat to receive heat from a gasification process or from biochar cooling. The processing chamber may be thermally coupled with a heat exchanger. The heat exchanger may comprise a heat sink. The heat exchanger may be configured to extract heat from exhaust gas. The heat exchanger may be configured to extract heat from the cooling chamber. The cooling chamber may comprise at least one gas inlet port. The apparatus may comprise at least one cooling chamber outlet coupled with a particulate filter. The apparatus may comprise at least one cooling chamber outlet coupled with a gas chromatograph. The apparatus may comprise at least one cooling chamber outlet coupled with a CO2removal filter. The apparatus may comprise at least one cooling chamber outlet coupled with an H2removal filter. The particulate filter may be serially coupled with the CO2removal filter. The particulate filter may be serially coupled with the H2removal filter. The CO2removal filter may be serially coupled with the H2removal filter. The CO2removal filter may have a mixed gas outlet. The CO2removal filter may have a CO2outlet. The H2removal filter may have a mixed gas outlet. The CO2removal filter may have an H2outlet. The apparatus may comprise a flange configured to be fluidly coupled with the cooling chamber. The cooling chamber may be fluidly coupled with the flange by a discharge valve. The flange fluidly coupled with the cooling chamber may be configured to be fluidly coupled with a biochar processing system. The apparatus may comprise a tail gas recycle loop. The tail gas recycle loop may fluidly couple at least one cooling chamber gas inlet port with at least one removal filter mixed gas outlet. The at least one removal filter mixed gas outlet coupled with the at least one cooling chamber gas inlet port may be an H2removal filter mixed gas outlet. The removal filter mixed gas outlet coupled with the at least one cooling chamber gas inlet port may be a CO2removal filter mixed gas outlet. The tail gas recycle loop may fluidly couple at least one cooling chamber gas inlet port with at least one removal filter mixed gas outlet and a thermal oxidizer. The thermal oxidizer may be thermally coupled with a heat exchanger that is configured to be thermally coupled with the processing chamber. The apparatus may further comprise a control system configured to cool hot biochar. Cooling hot biochar may comprise operably couple one or more discharge valve and one or more feed mechanism to receive hot biochar in the processing chamber, process the biochar based on heating the biochar in the processing chamber, retain the biochar in the processing chamber for a predetermined time or until the biochar reaches a predetermined temperature, direct the biochar in the processing chamber into the cooling chamber, inject cool gas from the gas inlet port into the cooling chamber to cool the biochar, retain the gas and biochar in the cooling chamber until the biochar is cooled to a predetermined temperature, and discharge the cooled biochar from the cooling chamber.

The method may comprise steam direct biochar cooling. The method may comprise hydrocarbon gas direct biochar cooling. The method may comprise hydrocarbon gas direct biochar cooling with tail gas recycling.

The steam direct biochar cooling method may comprise receiving hot biochar in a cooling chamber, injecting cool steam into the cooling chamber, retaining the cool steam and biochar in the cooling chamber until the biochar is cooled to a predetermined temperature, directing the cooled biochar into the drying chamber, injecting dry gas into the drying chamber, retaining the dry gas and biochar in the drying chamber until the biochar is dried to a predetermined moisture level, and discharging the dried cooled biochar from the drying chamber. Receiving hot biochar in the cooling chamber may comprise operably coupling one or more discharge valve and one or more feed mechanism to receive the hot biochar. Injecting cool steam into the cooling chamber may comprise injecting cool steam from the steam loop into the cooling chamber to cool the hot biochar. Injecting dry gas into the drying chamber may comprise injecting dry gas from the gas loop into the drying chamber to dry the moist biochar. Discharging the dried cooled biochar from the drying chamber may comprise operably coupling one or more discharge valve to discharge the dried cooled biochar.

The hydrocarbon gas direct biochar cooling method may comprise receiving hot biochar in a processing chamber, processing the biochar based on heating the biochar in the processing chamber, retaining the biochar in the processing chamber until the biochar reaches a predetermined temperature, directing the biochar in the processing chamber into the cooling chamber, injecting cool gas into the cooling chamber to cool the biochar, retaining the gas and biochar in the cooling chamber until the biochar is cooled to a predetermined temperature, and discharging the cooled biochar from the cooling chamber. The method may comprise removing CO2from gas directed from the cooling chamber to a CO2removal filter. The method may comprise removing H2from gas directed from the CO2removal filter to an H2removal filter. The method may comprise recovering tail gas from the H2removal filter mixed gas outlet. The method may comprise recycling the tail gas through a tail gas recycle loop. Recycling the tail gas may comprise fluidly coupling at least one cooling chamber gas inlet port with the H2removal filter mixed gas outlet through the tail gas recycle loop. Recycling the tail gas may comprise fluidly coupling at least one cooling chamber gas inlet port with the H2removal filter mixed gas outlet and a thermal oxidizer through the tail gas recycle loop. The method may comprise recycling heat. Recycling heat may further comprise recycling heat generated from the tail gas by the thermal oxidizer. The method may comprise applying the heat generated from the tail gas by the thermal oxidizer to the processing chamber.

Various direct biochar cooling implementations may achieve one or more technical effect. For example, some direct biochar cooling implementations may reduce installation, component, or maintenance cost. This facilitation may be a result of a direct biochar cooling implementation designed to directly cool biochar using cool gas comprising steam or hydrocarbons, without a need for additional components to cool the biochar, such as, for example, a heat exchanger, or a cooling tower. Some direct biochar cooling implementations may reduce operation cost. Such reduced operation cost may be a result of a direct biochar cooling implementation designed to directly cool biochar using cool gas comprising steam or hydrocarbons, without requiring additional energy inputs to cool the biochar using additional cooling components. In some direct biochar cooling designs, valuable byproducts may be produced. For example, biochar produced by steam direct cooling may be valued at a higher price point than standard biochar produced by indirect cooling, and the biochar produced by steam direct cooling may be a competitive alternative to activated carbon. Such higher-valued biochar produced by steam direct cooling may be a result of greater biochar surface area relative to standard biochar produced by indirect cooling.

Some direct biochar cooling implementations may produce biochar valued as a high-grade carbon manufacturing input. For example, biochar produced by some hydrocarbon direct cooling implementations may be valued at a higher price point than standard biochar. This facilitation may be a result of high grade carbon growth from the decomposition of CH4in the gas, produced by hydrocarbon direct cooling of the biochar. Some direct biochar cooling implementations may produce a value-add chemical byproduct. Such a value-add chemical byproduct may be a result of recycling and selling cooled hydrocarbon captured from an exemplary hydrocarbon direct cooling implementation. Various direct biochar cooling implementations may enhance biochar quality. Such enhanced biochar quality may be a result of directly cooling hot biochar resulting from gasification. Some direct biochar cooling implementations may capture hydrogen resulting from gasification. Such captured hydrogen production may enhance the efficiency of transition from a carbon-based economy, and improve the usefulness of gasification technology.

In the case of hydrocarbon direct biochar cooling, a portion of the hydrocarbon gas may decompose with carbon attaching to biochar and hydrogen flowing through in the hot hydrocarbon mixed gas. The hot hydrocarbon mixed gas may be cooled, and hydrogen may be stripped out or captured with a filter. In an illustrative example, ten percent or more hydrogen may be required to commercially apply such an exemplary filtration approach and recycle the cooled hydrocarbon mixed gas back to the direct cooling step, with make-up from the pipeline, wellhead, digester, or the like, to repeat the process. In an illustrative example, this recovered hydrogen may be sold as a value-add chemical byproduct of an exemplary hydrocarbon direct biochar cooling system.

In an illustrative example, a direct biochar cooling implementation in accordance with the present disclosure may directly cool hot biochar resulting from gasification, and in the process, enhance the biochar quality, or enhance the biochar quality and generate hydrogen.

In some implementations, an exemplary biochar and bio fly ash cooling apparatus may be a counter flow, direct contact exchange system operating on principles similar to a standpipe. An exemplary apparatus may include a metal cylinder of an appropriate composition for the conditions, but may require a refractory or other lining for high temperature operation. In various examples illustrative of the design and usage of various biochar cooling implementations in accordance with the present disclosure, solids may enter the top of an exchanger and flow via gravity through the cooler, exiting at the bottom. In such an example, the gas stream may enter the cooler near the bottom of the cooler, and flow upward through the solids. The gas may also serve to fluidize the solids, enhancing the solids' flow through the cooler. In various exemplary implementations, the method of introducing the gas may vary depending on, for example, flow and cooler size, however the method of introducing the gas may either utilize a gas distributor in larger systems, or fluidization nozzles at the wall for smaller coolers. The gas may exit near the top of the cooler. Depending on application, a separation device, such as a small cyclone or filter, may be needed to disengage the gas and solids at the gas exit.

In various examples illustrative of prior art biochar cooling implementation design and usage, there do not appear to be any biochar cooling approach to hot carbonaceous residue that utilizes an exemplary steam direct biochar cooling or hydrocarbon gas direct biochar cooling design in accordance with the present disclosure.

Throughout this disclosure, the term “fluid” is used interchangeably with the term “gas.” For example, an element that is “fluidly coupled” or “fluidly connected” or in “fluid communication” is capable to or would be capable to be in a coupled, connected, or communication mode with respect to gas, fluid, gas and fluid, gas or fluid, or any combination or mixture of gas or fluid. Throughout this disclosure, an element that is “fluidly coupled” or “fluidly connected” or in “fluid communication,” as the terms are used herein, is also capable to or would be capable to be in a coupled, connected, or communication mode with respect to fluid, solids, fluid and solids, fluid or solids, or any combination or mixture of fluid or solids.

The details of various aspects are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.

