EA041920B1 - INTEGRATION OF FERMENTATION AND GASIFICATION - Google Patents

Description

Technical field

This invention relates to methods for improving the integration of gas fermentation with gasification. In particular, this invention relates to the recycling of one or more effluents from a gas fermentation process to a gasification process.

State of the art

As the world's population increases, the waste generated by that population becomes an increasing problem. One solution for waste disposal is gasification. Gasification is the process of converting organic or fossil fuel carbonaceous materials into synthesis gas containing carbon monoxide, carbon dioxide and hydrogen. Gasification beneficially reduces the amount of waste that ends up in landfill and produces a product, syngas, that can be converted into useful products by one or more downstream processes.

The synthesis gas produced by gasification can be used in a number of processes, including Fischer-Tropsch synthesis. The Fischer-Tropsch synthesis provides for the catalytic hydrogenation of carbon monoxide to produce a variety of products, including hydrocarbons, alcohols, or other oxygenated hydrocarbons. However, Fischer-Tropsch catalyst beds are particularly sensitive to various components that may be present in the synthesis gas stream, depending on the gasification feedstock. One of these components is sulfur. If sulfur is not removed from the synthesis gas stream before being introduced into the Fischer-Tropsch synthesis, sulfur can deactivate the catalysts required for the Fischer-Tropsch reaction. Thus, in order to obtain a suitable gas for Fischer-Tropsch synthesis, large-scale gas purification technology is often required.

One alternative to Fischer-Tropsch synthesis is gas fermentation. Gas fermentation provides biological fixation of gases, including synthesis gas, into one or more products. Gas fermentation has a number of advantages over Fischer-Tropsch synthesis. First, the Fischer-Tropsch synthesis uses high temperatures (150-350°C), elevated pressures (30 bar) and heterogeneous catalysts such as cobalt, ruthenium and iron. In comparison, gas fermentation occurs at about 37°C and is often carried out at atmospheric pressure, which results in significant energy and cost savings compared to Fischer-Tropsch synthesis. In addition, Fischer-Tropsch synthesis requires a relatively fixed H ₂ :CO ratio in the synthesis gas of about 2:1, while gas fermentation is able to produce and use a wide range of substrates with different H 2 :CO ratios.

The wastewater treatment process is often combined with both a Fischer-Tropsch synthesis and a gas fermentation process. A typical wastewater treatment process may include several distinct treatment steps such as product removal, anaerobic digestion, and biological oxidation. Such purification steps are designed to remove various components and obtain a purified water stream. The removal of these components often results in the formation of significant amounts of solid waste. When treating wastewater, consideration must be given to what to do with the solid waste generated from the process.

In addition to the generation of solid waste, the wastewater treatment process, in particular the anaerobic digestion stage, generates biogas. Biogas typically contains about 60% methane and 40% carbon dioxide. Combined heat and power or biogas cogeneration (CHP) is a common way to use biogas, usually in a biogas engine where the biogas is burned to generate electricity and useful heat. However, biogas contains various components that must be removed before it can be used in a biogas engine. One of these components is water vapor. Biogas contains water vapor generated by the raw material production process. Before using biogas in a biogas engine, the water vapor content must be reduced to an acceptable level to avoid combustion problems. Biogas also contains various sulfur compounds, such as hydrogen sulfide, which, when burned in an engine, can condense with water to form sulfuric acid. Sulfuric acid is highly corrosive and can damage a biogas engine. To avoid the formation of sulfuric acid, it may be necessary to remove hydrogen sulfide. The costs associated with these removal processes need to be considered when making decisions about how to treat the biogas generated from the wastewater treatment process.

Accordingly, there remains a need for an integrated system that effectively integrates gasification, gas fermentation and wastewater treatment in an efficient manner so as to efficiently handle the effluents generated during the process.

The essence of the invention

The invention provides a method for improving the integration of a gas fermentation process with a gasification process, whereby at least a portion of one or more effluent streams from the gas fermentation process is recovered and sent to the gasification process. In particular embodiments, the effluent is selected from the group consisting of biogas from a wastewater treatment process, tail gas from a fermentation process, unused synthesis gas from a gasification process, microbial biomass from a fermentation process. , microbial biomass from the wastewater treatment process, crude ethanol from the product isolation process, fusel oil from the product isolation process, water depleted of microbial biomass, wastewater from the fermentation process, and clarified water from the process wastewater treatment.

In one or more preferred embodiments, the fermentation process uses one or more C1-fixing microorganisms suitable for the fermentation of a C1-containing gaseous substrate, such as synthesis gas produced by gasification. In those embodiments in which the C1 fixing microorganism is selected from the group consisting of Moorella, Clostridium, Ruminococcus, Acetobacterium, Eubacterium, Butyribacterium, Oxobacter, Methanosarcina, and Desulfotomaculum. Preferably the microorganism is a member of the genus Clostridium. In certain instances, the microorganism is Clostridium autoethanogenum.

In various embodiments, at least a portion of the at least one effluent is subjected to gasification to produce a synthesis gas stream. In certain instances, multiple effluent streams are gasified to produce a synthesis gas stream. Preferably, at least two effluent streams are gasified to produce a synthesis gas stream. Preferably, at least one effluent from the fermentation process and at least one effluent from the wastewater treatment process are gasified to produce a synthesis gas stream. At least a portion of the synthesis gas stream is preferably sent to a fermentation process to produce one or more products and/or by-products.

In specific embodiments, the microbial biomass obtained from the fermentation process is sent to the gasification process. In various cases, at least a portion of the microbial biomass obtained from the fermentation process is dried before being fed into the gasification process. In certain instances, substantially all of the microbial biomass produced in the fermentation process is dried prior to being fed into the gasification process.

In specific cases, substantially all of the microbial biomass produced from the fermentation process is either reused in the fermentation process after product production, or treated with a wastewater treatment process, and/or sent to a gasification process to produce synthesis gas. In certain cases, the gasification process receives at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% of the microbial biomass or substantially all of the microbial biomass from the fermentation process.

In specific embodiments, the microbial biomass obtained from the wastewater treatment process is sent to the gasification process. The microbial biomass generated from the wastewater treatment process may, at least in part, be obtained from a process using an anaerobic bioreactor in the wastewater treatment process. In various cases, at least a portion of the microbial biomass obtained from the wastewater treatment process is dried before being fed into the gasification process. In certain instances, substantially all of the microbial biomass from the wastewater treatment process is dried prior to being fed into the gasification process.

In certain embodiments, at least a portion of the water depleted in microbial biomass during the fermentation process is sent to the gasification process. In various cases, water depleted of microbial biomass is sent to the gasification process to increase the H ₂ :CO ratio in the synthesis gas stream. Preferably, at least a portion of the microbial biomass depleted water is sent to the gasification process to increase the H ₂ :CO ratio in the synthesis gas stream to at least 2:1, at least 3:1, or at least 4:1. The direction of water depleted in microbial biomass into the gasification process, in which the ratio of H2:CO in the synthesis gas stream increases, can lead to an increase in selectivity to ethanol produced in the gas fermentation process, a decrease in selectivity to obtain microbial biomass, a decrease in water consumption as a result fermentation reactions and/or reduction of effluent in the wastewater treatment process.

In certain embodiments, at least a portion of the wastewater generated from the fermentation process is sent to the gasification process. This wastewater may contain one or more products and/or by-products, including, without limitation, microbial biomass. In various cases, the wastewater generated during the fermentation process is sent to the gasification process to increase the H2:CO ratio in the synthesis gas stream. Preferably, at least a portion of the wastewater generated from the fermentation process is sent to the gasification process to increase the H ₂ :CO ratio in the synthesis gas stream to at least 2:1, at least 3:1, or at least 4:1 . The direction of wastewater generated during the fermentation process into the gasification process, in which the ratio of H2:CO in the synthesis gas stream increases, can lead to an increase in selectivity for ethanol produced in the gas fermentation process, a decrease in selectivity for obtaining microbial biomass, and a decrease in water consumption. as a result of a fermentation reaction and/or a reduction in effluent during the wastewater treatment process.

- 2 041920

In certain embodiments, at least a portion of the clarified water from the wastewater treatment process is sent to the gasification process. In various cases, the clarified water obtained from the wastewater treatment process is sent to the gasification process to increase the H ₂ :CO ratio in the synthesis gas stream. Preferably, at least a portion of the clarified water from the wastewater treatment process is sent to the gasification process to increase the H ₂ :CO ratio in the synthesis gas stream to at least 2:1, at least 3:1, or at least 4 :1. The direction of the clarified water obtained in the wastewater treatment process into the gasification process, in which the ratio of H ₂ :CO in the synthesis gas stream increases, can lead to an increase in selectivity for ethanol produced in the gas fermentation process, a decrease in selectivity for obtaining microbial biomass, reducing water consumption as a result of the fermentation reaction and/or reducing the discharge flow in the wastewater treatment process.

Preferably, at least a portion of the at least one effluent from the fermentation process and/or the wastewater treatment process is replaced with at least a portion of the process water required for the gasification process. In certain cases, the amount of process water required for the gasification process is reduced by at least 45%. In at least one embodiment, the amount of process water required for the gasification process is reduced by 45-100%. In certain embodiments, the amount of process water required for the gasification process is reduced by 45-75%, 55-75%, 65-75%, 55-100%, 65-100%, or 75-100%.

In certain instances, at least a portion of the at least one effluent stream is introduced into the synthesis gas stream resulting from the gasification process to reduce the temperature of the synthesis gas stream. Preferably, the effluent injected into the synthesis gas stream from the gasification process is selected from the group consisting of microbial biomass-depleted water, wastewater from the fermentation process, and clarified water from the wastewater treatment plant.

Preferably, the temperature of the synthesis gas stream is reduced by at least 100°C. In at least one embodiment, the temperature of the synthesis gas stream leaving the gasification process is between 800 and 1200°C. Preferably, the temperature of the synthesis gas stream is reduced in a temperature range suitable for further gas purification and/or fermentation. In various cases, the introduction of at least one effluent stream into the synthesis gas stream is performed to remove at least one particle from the synthesis gas stream.

In certain cases, the synthesis gas flow is partially suppressed. Preferably, the syngas stream is partially suppressed by introducing one or more effluent streams into the synthesis gas stream, the one or more effluent streams being selected from the group consisting of microbial biomass-depleted water, fermentation wastewater, and clarified water from a plant for wastewater treatment. In various embodiments, partial suppression of the synthesis gas stream reduces the temperature of the synthesis gas stream to 700-800°C. In various embodiments, this temperature reduction requires approximately 1.2 tons of process water per 10,000 Nm ³ of suppressed synthesis gas starting at 1000°C. Preferably at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% process water or substantially all of that process water is replaced by introducing one or more effluent streams into the synthesis gas stream.

In certain cases, the synthesis gas flow is completely suppressed. Preferably, the syngas stream is completely suppressed by introducing one or more effluent streams into the synthesis gas stream, the one or more effluent streams being selected from the group consisting of microbial biomass-depleted water, fermentation wastewater, and clarified water from a plant for wastewater treatment. In various embodiments, complete suppression of the syngas stream reduces the temperature of the syngas stream to less than 300°C. In various embodiments, this temperature reduction requires approximately 4 tons of process water per 10,000 Nm ³ of suppressed synthesis gas starting at 1000°C. Preferably at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% process water or substantially all of that process water is replaced by introducing one or more effluent streams into the synthesis gas stream.

In particular embodiments, at least a portion of the biogas generated from the wastewater treatment process is sent to the gasification process. This biogas may contain one or more components selected from the group consisting of methane, carbon dioxide, carbon monoxide, ammonia and a sulfur compound. In various instances, this sulfur compound is hydrogen sulfide. In at least one embodiment, the biogas contains about 60% methane and about 40% carbon dioxide. In at least one embodiment, the biogas contains about 65% methane and about 35% carbon dioxide.

In particular embodiments, at least a portion of the biogas generated from the wastewater treatment process is used as a heat source. Preferably, at least a portion of the biogas generated from the wastewater treatment process is used as a heating source in

- 3 041920 gasification process. In various cases, at least a portion of the biogas sent to the gasification process is used as a heat source to melt at least a portion of the slag generated in the gasification process. In one or more embodiments, the biogas from the wastewater treatment process is sent to a process for removing certain substances before being sent to the gasification process. In various cases, the removal process includes one or more removal modules capable of removing, converting and/or reducing the amount of at least one component in the biogas stream. Preferably, the removal process removes at least a portion of the at least one sulfur compound from the biogas stream before directing the biogas stream to the gasification process.

In particular embodiments, at least a portion of the methane in the biogas is reformed to produce CO and H ₂ after undergoing gasification in the gasification process. In various cases, methane reacts with the moisture contained in the synthesis gas to produce carbon monoxide and hydrogen.

In specific embodiments, at least a portion of the tail gas generated from the fermentation process, unused synthesis gas from the gasification process, crude ethanol from the product recovery process, and/or fusel oil from the product recovery process is used as the source. heating. Preferably, at least a portion of at least one of these effluent streams is used as a heat source in the gasification process. In various cases, at least a portion of at least one of these effluent streams is sent to the gasification process for use as a heat source for melting at least a portion of the slag generated in the gasification process. In one or more embodiments, these effluents are treated in a removal process before being sent to the gasification process. In various cases, the removal process includes one or more removal modules capable of removing, converting and/or reducing the amount of at least one component in the output stream.

In addition to directing at least a portion of the clarified water from the wastewater treatment process to the gasification process, at least a portion of the clarified water generated from the wastewater treatment process may be directed to the fermentation process. In specific cases, substantially all of the clarified water generated from the wastewater treatment process is recycled to either the gasification process and/or the fermentation process. In certain cases, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, according to at least 80%, at least 90% of the clarified water, or essentially all of the clarified water obtained from the wastewater treatment process. In certain cases, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, according to at least 80%, at least 90% of the clarified water, or essentially all of the clarified water obtained from the wastewater treatment process.

Preferably, the fermentation process uses at least a portion of the synthesis gas produced in the gasification process to produce one or more fuels or chemicals. At least one of the fermentation products may be selected from the group consisting of ethanol, acetate, butanol, butyrate, 2,3-butanediol, 1,3-butanediol, lactate, butene, butadiene, methyl ethyl ketone, ethylene, acetone , isopropanol, lipids, 3-hydropropionate, terpenes (including but not limited to isoprene), fatty acids, 2-butanol, isobutylene, isobutanol, 1,2-propanediol, 1-propanol, and C ₆ -C ₁₂ alcohols.

In one or more embodiments, at least a portion of the microbial biomass resulting from the fermentation process can be converted to a single cell protein (SCP; single cell protein).

In various cases, at least a portion of one or more fuels or chemicals are sent to a secondary conversion process. Preferably, the secondary conversion process further converts at least one or more fuels or chemicals into at least one component of diesel, jet fuel, gasoline, propylene, nylon 6-6, rubber and/or resins.

In one or more embodiments, the synthesis gas produced from the gasification process is sent to a removal process prior to being sent to the fermentation process. In various cases, the removal process includes one or more removal modules capable of removing, converting and/or reducing the amount of microbial inhibitors and/or catalyst inhibitors contained in the synthesis gas stream.

Preferably, at least one component removed, converted, or reduced in the synthesis gas stream during the removal process is selected from the group consisting of sulfur compounds, aromatics, alkynes, alkenes, alkanes, olefins, nitrogen compounds, phosphorus compounds, solid impurities, solid particles, oxygen, halogenated compounds, silicon compounds, carbonyls, metals, alcohols, esters, ketones, peroxides, aldehydes, esters and resins.

Preferably, at least one removal module may be selected from the group consisting of a hydrolysis module, an acid gas removal module, a deoxygenation module, a catalytic hydrogenation module, a particle removal module, a chloride removal module, a tar removal module, and a hydrogen cyanide purification module. . In various cases, the removal process includes at least two removal modules.

The invention may further provide for increasing and/or decreasing the pressure of the synthesis gas stream at one or more points in the process.

Brief description of graphic materials

In FIG. 1 is a process integration diagram depicting the integration of a gasification process, a gas fermentation process, a product recovery process, and a wastewater treatment process in accordance with one aspect of the present invention.

In FIG. 2 shows the process integration diagram shown in FIG. 1 further comprising a removal process between the gasification process and the gas fermentation process, in accordance with one aspect of the present invention.

In FIG. 3 shows the process integration diagram shown in FIG. 2 further comprising a removal process after the wastewater treatment process, in accordance with one aspect of the present invention.

Detailed description of the invention

The inventors have determined that the integration of the fermentation process and the wastewater treatment process with the gasification process, whereby the effluent stream downstream of the fermentation process is recycled to the gasification process, can provide significant benefits to the efficiency of one or more processes.

Definitions

Unless otherwise indicated, the following terms used in this specification have the following meanings.

The terms increased efficiency, increased efficiency, and the like, when used in relation to a fermentation process, include, without limitation, an increase in one or more growth rates of fermentation catalysing microorganisms, growth and/or production rate at higher product concentrations, an increase in volume of the desired product produced per volume of substrate consumed, an increase in the rate of production or level of production of the desired product and the relative content of the desired product obtained compared to other fermentation by-products, a decrease in the amount of water consumed in the process, and a decrease in the amount of energy used in the process.

The terms efficiency improvement, efficiency improvement, and the like, when used in relation to a gasification process, include, but are not limited to, increasing the amount of synthesis gas produced in the process, reducing the amount of feed water used in the process, optimizing the synthesis gas flow for gas fermentation, reducing greenhouse gas emissions and reducing the amount of energy, including, without limitation, external fuel used in the process.

The terms improved efficiency, improved efficiency, and the like, when used in relation to a wastewater treatment process, include, but are not limited to, reducing the retention time of water in the process, increasing the use of biogas generated in the process, reducing the amount of effluent sent to the process wastewater treatment, reducing the volume required for the process, reducing the need for separation of ammonia in the process and reducing the amount of energy used in the process.

The terms fermentation, gas fermentation, etc. should be interpreted as a process in which one or more substrates are introduced, such as synthesis gas obtained through gasification, and one or more products are obtained by using one or more C1-fixing microorganisms. Preferably, the fermentation process includes the use of one or more bioreactors. The fermentation process can be described as either batch or continuous. Batch fermentation is used to describe a fermentation process in which a bioreactor is filled with a feedstock, such as a carbon source, along with microorganisms, with the products remaining in the bioreactor until the fermentation is completed. In a batch process, after the fermentation is complete, the products are removed and the bioreactor is cleaned before starting the next batch. Continuous fermentation is used to describe a fermentation process where the fermentation process is extended for longer periods of time and the product and/or metabolite is recovered during the fermentation. Preferably the fermentation process is continuous.

The term wastewater treatment, etc. should be interpreted as a process that separates components from the effluent from the fermentation process to produce clarified water. The wastewater treatment process may include, without limitation, one or more anaerobic bioreactors with different residence times and one or more ammonia stripping processes.

The term gasification, etc. should be interpreted as a process that converts carbonaceous materials based on organic or fossil fuels into carbon monoxide (CO), hydrogen (H ₂ ) and carbon dioxide (CO ₂ ). The gasification process may include various technologies,

- 5 041920 including, without limitation, counterflow fixed bed gasifiers, cocurrent fixed bed gasifiers, fluidized bed reactors, gasifiers with gasification in the stream and plasma gasifiers. The gasification process can use any feedstock from which a synthesis gas stream can be obtained. The term gasification process encompasses the gasifier itself, along with the individual gasification-related operations, including the heat source for the gasifier and the synthesis gas suppression processes.

The terms synthesis gas stream, synthesis stream, etc. refers to the gaseous substrate resulting from the gasification process. The synthesis gas stream should primarily consist of carbon monoxide (CO), hydrogen (H ₂ ) and carbon dioxide (CO 2 ). The composition of the syngas stream can vary considerably depending on the feedstock and the gasification process involved; however, a typical syngas composition is 30 to 60% carbon monoxide (CO), 25 to 30% hydrogen ( _H2 ), 0 to 5% methane (CH4), 5 to 15% carbon dioxide ( _CO2 ) , as well as more or less water vapor, smaller amounts of sulfur compounds, hydrogen sulfide (H2S), carbonyl sulfide (COS), ammonia (NH ₃ ) and other trace impurities.

In specific embodiments, the presence of hydrogen leads to an improvement in the overall efficiency of obtaining alcohol in the fermentation process.

The composition of the synthesis gas can be improved to provide the required or optimal ratio of H ₂ :CO:CO ₂ . The composition of the synthesis gas can be improved by adjusting the feedstock fed into the gasification process. The required ratio of H ₂ :CO:CO ₂ depends on the desired fermentation product obtained in the fermentation process. For ethanol, the optimal ratio of H ₂ :CO:CO ₂ is as follows:

where x>2y, to match the stoichiometry for obtaining ethanol (x) R ₂ + (y) CO + (^) CO ₂ -> (^) C ₂ H _S OH + (^) H ₂ O.

The implementation of the fermentation process in the presence of hydrogen has the additional advantage of reducing the amount of CO ₂ produced in the fermentation process. For example, a gaseous substrate containing a minimal amount of H2 usually turns into ethanol and CO2 with the following stoichiometry: [6CO + H ₂ O ^ C ₂ H ₅ OH + CO ₂ ]. As the amount of hydrogen used by C1-fixing bacteria increases, the amount of CO ₂ produced decreases [eg CO + H2 ^ C2H5OH + H2O].

When CO is the only source of carbon and energy for ethanol production, some of the carbon is lost to the formation of CO ₂ according to the equation:

CO + 3 H ₂ O C2H5OH + 4 CO ₂ (ΔΟ ⁰ \u003d -224.90 kJ / mol of ethanol)

With an increase in the amount of H ₂ available in the substrate, the amount of CO ₂ formed decreases. With a stoichiometric ratio of 2:1 (H ₂ :CO), the formation of CO ₂ is completely excluded.

CO + 1 H ₂ + 2 H ₂ O 1 C ₂ H ₅ OH + 3 CO ₂ (DS ° = -204.80 kJ / mol of ethanol)

CO + 2 H ₂ + 1 H ₂ O 1 C ₂ H ₅ OH + 2 CO ₂ (DS ° = -184.70 kJ / mol of ethanol)

CO + 3 H ₂ 1 C ₂ H ₅ OH + 1 CO ₂ (ΔΟ ⁰ \u003d -164.60 kJ / mol of ethanol)

Flow refers to any substrate that can be directed, for example, from one process to another, from one module to another, and/or from one process to a carbon capture device.

As used herein, the term reactants refers to a substance that takes part and undergoes change during a chemical reaction. In specific embodiments of the invention, the reagents include, without limitation, CO and/or H2.

As used herein, the term microbial inhibitors refers to one or more components that slow or interfere with a particular chemical reaction or other process involving microorganisms. In particular embodiments, microbial inhibitors include, without limitation, oxygen (O ₂ ), hydrogen cyanide (HCN), acetylene (C ₂ H ₂ ), and BTEX (benzene, toluene, ethylbenzene, xylene).

As used herein, a catalyst inhibitor, an adsorbent inhibitor, and the like. refers to one or more substances that slow down or interfere with a chemical reaction. In particular embodiments, catalyst and/or adsorbent inhibitors may include, without limitation, hydrogen sulfide (H2S) and carbonyl sulfide (COS).

Terms removal process, removal module, cleaning module, etc. include technologies that are capable of converting and/or removing microbial inhibitors and/or catalyst inhibitors from a gas stream. In particular embodiments, catalyst inhibitors must be removed by the upstream removal module to prevent inhibition of one or more catalysts in the downstream removal module.

As used in this document, the terms components, impurities, etc. belong to inhibito

- 6 041920 frames of microorganisms and/or inhibitors of catalysts, which may be present in the gas stream. In specific embodiments, the components include, without limitation, sulfur compounds, aromatics, alkynes, alkenes, alkanes, olefins, nitrogen compounds, phosphorus compounds, fine particles, particulate matter, particulate matter, oxygen, halogenated compounds, silicon compounds, carbonyls, metals , alcohols, esters, ketones, peroxides, aldehydes, esters and resins.

The terms purified gas, purified stream, etc. refer to a gas stream that has been passed through at least one removal module and in which one or more components have been removed and/or converted.

As used herein, the term carbon capture refers to the removal of carbon compounds, including CO2 and/or CO, from a stream containing CO2 and/or CO, and either:

converting CO2 and/or CO into products; or converting CO2 and/or CO into substances suitable for long-term storage; or capturing CO2 and/or CO in substances suitable for long-term storage; or a combination of these processes.

The term bioreactor, reactor, etc. includes a fermentation device consisting of one or more tanks and / or tower-type structures or pipelines, which includes a continuous stirred tank reactor (CSTR; Continuous Stirred Tank Reactor), an immobilized cell reactor (ICR; Immobilized Cell Reactor), trickled bed reactor (TBR; Immobilized Cell Reactor), bubble column, gas lift fermenter, static mixer, circulating loop reactor, membrane reactor such as Hollow Fiber Membrane Bioreactor (HFM BR), or other vessel or other device suitable for gas-liquid contact. The bioreactor is preferably configured to produce a gaseous substrate containing CO or CO 2 or H ₂ or mixtures thereof. The reactor may contain a plurality of reactors (stages) arranged in parallel or in series. For example, the reactor may comprise a first growth reactor in which bacteria are cultured and a second fermentation reactor into which fermentation broth can be fed from the growth reactor and in which most of the fermentation products can be produced.

Culture media or growth media are used to describe a bacterial growth medium. Preferably, the nutrient medium inside the bioreactor is used in the fermentation process. Typically, this term refers to a medium containing nutrients and other components suitable for the growth of a microbial culture. The term nutrient includes any substance that can be used in the metabolic pathway of a microorganism. Typical nutrients include potassium, B vitamins, trace metals and amino acids.

The term fermentation broth or broth encompasses a mixture of components, including a growth medium and a culture, or one or more microorganisms. Preferably, the fermentation process uses a fermentation broth to ferment the synthesis gas stream into one or more products.

As used herein, the term acid includes both carboxylic acids and their associated carboxylate anion, such as a mixture of free acetic acid and acetate present in a fermentation broth as described herein. The ratio of molecular acid and carboxylate in the fermentation broth depends on the pH of the system. In addition, the term acetate includes both an acetic acid salt and a mixture of molecular or free acetic acid and an acetic acid salt, such as a mixture of an acetic acid salt and free acetic acid present in a fermentation broth as described herein.

The term required composition is used to refer to the required level and types of components in a substance, such as, for example, a gas stream, including, without limitation, synthesis gas. In particular, a gas is considered to have the required composition if it contains a specific component (for example, CO, H ₂ and/or CO ₂ ) and/or contains a specific component in a specific proportion and/or does not contain a specific component (for example, a component, harmful to microorganisms) and/or does not contain a specific component in a specific proportion. More than one component may be considered in determining whether a gas stream has the desired composition.

Unless the context implies otherwise, the expressions fermentation, fermentation process or fermentation reaction, and the like. herein include both a growth phase and a gaseous substrate biosynthesis phase.

A microorganism is a microscopic organism, such as a bacterium, archaea, virus, or fungus. The microorganism according to this invention is usually a bacterium. As used herein, the term microorganism is intended to include a bacterium. It should be noted that the term microorganism and the term bacteria are used interchangeably throughout this document.

The parent microorganism is the microorganism used to produce the microorganism of this invention. The parent microorganism may be

- 7 041920 a naturally occurring microorganism (eg a wild-type microorganism) or a microorganism that has been previously modified (eg a mutant or recombinant microorganism). The microorganism of the present invention may be modified to express or overexpress one or more enzymes that were not expressed or overexpressed in the parent microorganism. Likewise, the microorganism of the present invention may be modified to contain one or more genes that were not contained in the parent microorganism. The microorganism of the present invention may also be modified not to express or to express lower amounts of one or more enzymes that were expressed in the parent microorganism. In one embodiment, the parent microorganism is Clostridium autoethanogenum, Clostridium ljungdahlii, or Clostridium ragsdalei. In a preferred embodiment, the parent microorganism is Clostridium autoethanogenum LZ1561, which was deposited June 7, 2010 at the German Collection of Microorganisms and Cell Cultures (DSMZ; Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH) located at Inhoffenstraβ 7B, D-38124 Braunschweig , Germany, dated June 7, 2010, in accordance with the terms of the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure, under registration number DSM23693. This strain is described in International Patent Application No. PCT/NZ2011/000144 published as WO 2012/015317.

The term derived from indicates that a nucleic acid, protein, or microorganism is modified or adapted from another (eg, parental or wild-type) nucleic acid, protein, or microorganism to produce a new nucleic acid, protein, or microorganism. Such modifications or adaptations typically include the insertion, deletion, mutation, or substitution of nucleic acids or genes. As a rule, the microorganism according to this invention is derived from the parent microorganism. In one embodiment, the implementation of the microorganism according to this invention is from Clostridium autoethanogenum, Clostridium ljungdahlii or Clostridium ragsdalei. In a preferred embodiment, the microorganism according to the invention is derived from Clostridium autoethanogenum LZ1561, which is deposited under DSMZ accession number DSM23693.

The term Wood-Ljungdahl refers to the Wood-Ljungdahl carbon fixation pathway described, for example, in Ragsdale, Biochim Biophys Acta, 1784:1873-1898, 2008. Wood-Ljungdahl microorganisms, as expected, refer to microorganisms containing the Wood-Ljungdahl pathway . As a rule, the microorganism according to this invention contains the native Wood-Ljungdal pathway. As used herein, the Wood-Ljungdahl pathway may be a native, unmodified Wood-Ljungdahl pathway, or may be a Wood-Ljungdahl pathway with some degree of genetic modification (e.g., overexpression, heterologous expression, knockout, etc.) as long as it is used to convert CO , CO ₂ and/or H ₂ in acetyl-CoA.

C1 refers to a molecule containing one carbon atom, such as CO, CO ₂ , CH ₄ or CH3OH. C1-oxygenate refers to a molecule containing one carbon atom, which also contains at least one oxygen atom, such as CO, CO ₂ or CH3OH. A C1 carbon source refers to a molecule containing one carbon atom that serves as a partial or sole carbon source for a microorganism according to the present invention. Thus, for example, the C1 carbon source may contain one or more of CO, CO ₂ , CH ₄ , CH3OH, or CH2O2. The C1 carbon source preferably contains one or both of CO and CO ₂ . A C1 fixing microorganism is a microorganism capable of producing one or more products from a C1 carbon source. Typically, the microorganism according to this invention is a C1-fixing bacterium.

Anaerobe is a microorganism that does not require oxygen for growth. The anaerobe can react negatively or even die in the presence of oxygen above a certain threshold. However, some anaerobes are able to tolerate low levels of oxygen (eg 0.000001-5% oxygen). As a rule, the microorganism according to this invention is an anaerobe.

Acetogens are obligate anaerobic bacteria using the Wood-Ljungdahl pathway as their primary mechanism for energy conservation and the synthesis of acetyl-CoA and acetyl-CoA derived products such as acetate (Ragsdale, Biochim Biophys Acta, 1784:18731898, 2008 ). In particular, acetogens use the Wood-Ljungdahl pathway as (1) a mechanism for the reductive synthesis of acetyl-CoA from CO2, (2) a terminal electron-withdrawing, energy-saving process, (3) a mechanism for fixing (assimilating) CO2 during the synthesis of cellular carbon (Drake, Acetogenic Prokaryotes, In: The Prokaryotes, ^3rd edition, p.354, New York, NY, 2006). All naturally occurring acetogens are C1-fixing, anaerobic, autotrophic, and non-methanotrophic. Typically, the microorganism according to this invention is an acetogen.

An ethanologen is a microorganism that produces or is capable of producing ethanol. Typically, the microorganism according to this invention is

- 8 041920 ethanologen.

An autotroph is a microorganism that can grow in the absence of organic carbon. Instead, autotrophs use inorganic carbon sources such as CO and/or CO2.

As a rule, the microorganism according to this invention is an autotroph.

A carboxydotroph is a microorganism capable of using CO2 as its sole source of carbon and energy. As a rule, the microorganism according to this invention is a carboxydotroph.

A methanotroph is a microorganism capable of using methane as its sole source of carbon and energy. In some embodiments, the microorganism of the invention is a methanotroph or is derived from a methanotroph. In other embodiments, the microorganism of the invention is not a methanotroph or is not descended from a methanotroph.

The substrate refers to a source of carbon and/or energy for the microorganism according to this invention. Typically, the substrate is gaseous and contains a source of C1 carbon, such as CO, CO2 and/or CH ₄ . The substrate preferably contains a source of C1-carbon in the form of CO or CO + CO2. The substrate may additionally contain other non-carbon components such as H ₂ or N 2 .

The term co-substrate refers to a substance which, although not necessarily the primary source of energy and material for product synthesis, can be used to synthesize a product when added to another substrate, such as the primary substrate.

The composition of the substrate can have a significant impact on the efficiency and/or cost of the reaction. For example, the presence of oxygen (O ₂ ) can reduce the efficiency of an anaerobic fermentation process. Depending on the composition of the substrate, it may be desirable to treat, purify or filter the substrate to remove any undesirable contaminants such as toxins, unwanted components or dust particles and/or to increase the concentration of desired components.

In certain embodiments, the fermentation is carried out in the absence of carbohydrate substrates such as sugar, starch, lignin, cellulose, or hemicellulose.

The microorganism according to this invention can be cultured with a gas flow to obtain one or more products. Thus, for example, the microorganism according to the invention can produce or can be genetically engineered to produce ethanol (WO 2007/117157), acetate (WO 2007/117157), butanol (WO 2008/115080 and WO 2012/053905), butyrate (WO 2008 /115080), 2,3-butanediol (WO 2009/151342 and WO 2016/094334), lactate (WO 2011/112103), butene (WO 2012/024522), butadiene (WO 2012/024522), methyl ethyl ketone (2-butanone ) (WO 2012/024522 and WO 2013/185123), ethylene (WO 2012/026833), acetone (WO 2012/115527), isopropanol (WO 2012/115527), lipids (WO 2013/036147), 3-hydroxypropionate (3 -HP) (WO 2013/180581), terpenes including isoprene (WO 2013/180584), fatty acids (WO 2013/191567), 2-butanol (WO 2013/185123), 1,2-propanediol (WO 2014/0369152 ), 1-propanol (WO 2014/0369152), products derived from chorismate (WO 2016/191625), 3-hydroxybutyrate (WO 2017/066498) and 1,3-butanediol (WO 2017/0066498). In some embodiments, the microbial biomass itself can be considered a product. These products can be further converted to produce at least one component of diesel fuel, jet fuel and/or gasoline. In addition, microbial biomass can be further processed to produce single cell protein (SCP).

Single cell protein (SCP) refers to microbial biomass that can be used in protein-rich human and/or animal feeds and foods, often replacing traditional sources of protein supplements such as soy products or fishmeal. To obtain a single cell protein or other product, the method may include additional steps of separation, processing or processing. For example, the method may include sterilizing the microbial biomass, centrifuging the microbial biomass, and/or drying the microbial biomass. In certain embodiments, the microbial biomass is dried using a spray dryer or paddle dryer. The method may also include reducing the nucleic acid content of the microbial biomass by any method known in the art, since consumption of a diet high in nucleic acid may lead to accumulation of nucleic acid degradation products and/or gastrointestinal distress. The single cell protein may be suitable for feeding animals such as livestock or pets. In particular, the pet food may be suitable for feeding one or more of cattle, dairy cattle, pigs, sheep, goats, horses, mules, donkeys, deer, buffalo/buffalo, llamas, alpacas, reindeer, camels, banteng , pigeons, yaks, chickens, turkeys, ducks, geese, quails, guinea fowls, squabs/pigeons, fish, shrimp, crustaceans, cats, dogs and rodents. The composition of the pet food can be adapted to the nutritional needs of different animals. In addition, the process may include mixing or combining the microbial biomass with one or more excipients.

An excipient can refer to any substance that can be added to a microbial

- 9 041920 biomass to improve or change the form, properties or nutritional value of animal feed. For example, the bulk may contain one or more of carbohydrates, fiber, fats, proteins, vitamins, minerals, water, flavors, sweeteners, antioxidants, enzymes, preservatives, probiotics, or antibiotics. In some embodiments, the filler may be hay, straw, silage, cereals, oils or fats, or other plant material. The filler can be any feed ingredient specified in Chiba, Section 18: Diet Formulation and Common Feed Ingredients, Animal Nutrition Handbook, 3rd revision, pages 575-633, 2014.

A native product is a product produced by a non-genetically modified microorganism. For example, ethanol, acetate and 2,3-butanediol are native products of Clostridium autoethanogenum, Clostridium Ijungdahlii and Clostridium ragsdalei. A non-native product is a product produced by a genetically modified microorganism, however, it is not produced by the non-genetically modified microorganism from which the genetically modified microorganism originates.

Selectivity refers to the ratio of the production of the target product to the production of all fermentation products produced by the microorganism. The microorganism according to this invention can be genetically engineered to produce products with a certain selectivity or with a minimum selectivity. In one embodiment, the target product is at least about 5%, 10%, 15%, 20%, 30%, 50%, or 75% of all fermentation products produced by the microorganism of the invention. In one embodiment, the target product is at least 10% of all fermentation products produced by the microorganism of the invention such that the microorganism of the invention has at least 10% selectivity for the target product. In yet another embodiment, the target product is at least 30% of all fermentation products produced by the microorganism of the invention, such that the microorganism of the invention has at least 30% selectivity for the target product.

The culture is usually maintained in an aqueous culture medium containing sufficient nutrients, vitamins and/or minerals to allow growth of the microorganism. The aqueous culture medium is preferably an anaerobic microbial growth medium, such as a minimal anaerobic microbial growth medium.

To obtain the target product, cultivation/fermentation is preferably carried out under appropriate conditions. As a rule, cultivation/fermentation is carried out under anaerobic conditions. Reaction conditions to be considered include pressure (or partial pressure), temperature, gas flow rate, liquid flow rate, medium pH, medium redox potential, agitation rate (when using a continuously stirred reactor), inoculum level, maximum gas substrate concentrations to ensure that gas in the liquid phase does not become a limiting factor, and maximum product concentrations to avoid product inhibition. In particular, the rate of introduction of the substrate can be controlled to ensure that the concentration of gas in the liquid phase does not become a limiting factor, since under conditions of limited amount of gas, the culture can consume products.

Operation of the bioreactor at elevated pressures provides an increased rate of gas mass transfer from the gas phase to the liquid phase. Accordingly, it is generally preferred to carry out the culture/fermentation at pressures above atmospheric pressure. In addition, since the desired gas conversion rate depends in part on the retention time of the substrate and the retention time determines the required volume of the bioreactor, the use of pressurized systems can significantly reduce the required volume of the bioreactor and hence the capital cost of the culture/fermentation equipment. This in turn means that by maintaining the bioreactors at elevated pressure rather than at atmospheric pressure, the retention time, defined as the volume of liquid in the bioreactor divided by the gas flow rate, can be reduced. The optimum reaction conditions will depend in part on the particular microorganism used. However, it is generally preferred to carry out the fermentation at a pressure above atmospheric pressure. In addition, since the desired gas conversion rate depends in part on the retention time of the substrate and achieving the desired retention time in turn determines the required bioreactor volume, the use of pressurized systems can significantly reduce the required bioreactor volume and hence the capital cost of the fermentation equipment.

Target products can be separated or purified from the fermentation broth by any suitable removal process that uses a method or combination of methods known in the art, including, for example, fractional distillation, vacuum distillation, evaporation, evaporation through a semi-permeable membrane, gas stripping, separation phases and extractive fermentation, including, for example, liquid phase extraction. In some embodiments, target products are isolated from the fermentation broth by continuous removal from the bioreactor

- 10 041920 parts of the broth, separating the microbial cells from the broth (usually by filtration) and isolating one or more desired products from the broth. Alcohols and/or acetone can be isolated, for example, by distillation. Acids can be isolated, for example, by adsorption on activated carbon. The separated microbial cells can be returned to the bioreactor. Cell-free permeate remaining after removal of the target products may also be returned to the bioreactor. Additional nutrients (such as B vitamins) can be added to the cell-free permeate to replenish the medium before it is returned to the bioreactor.

Description

The inventors have found that by integrating a fermentation process and/or a wastewater treatment process with a gasification process, the efficiency of one or more processes is increased. In particular, the inventors have identified the potential for integrating one or more effluent streams from a fermentation and/or wastewater treatment process into a gasification process for recycling.

The one or more effluents are preferably selected from the group consisting of biogas from the wastewater treatment process, tail gas from the fermentation process, unused synthesis gas from the gasification process, microbial biomass from the fermentation process, microbial biomass, from the wastewater treatment process, crude ethanol from the product recovery process, fusel oil from the product recovery process, water depleted in microbial biomass, wastewater from the fermentation process, and clarified water from the wastewater treatment process. One or more of these effluent streams may be sent to the gasification process to produce a synthesis gas stream used in the gasification process as a heating source and/or used in the gasification process to suppress the synthesis gas stream. This synthesis gas stream is preferably suitable for gas fermentation.

These various effluents are generated either upstream or downstream of the fermentation process. The fermentation process produces a wastewater stream containing organic metabolites such as microbial biomass, ethanol, acetate and 2-3-butanediol, as well as various inorganic compounds such as salts and trace metals. This wastewater stream is often sent to a wastewater treatment process. A typical wastewater treatment process includes the following steps: (i) separation of microbial biomass, which is a suspended solid; (ii) concentration of microbial biomass solids in a separate long residence time anaerobic bioreactor, approximately 30 days; (iii) concentration of the clarified effluent with reduced amounts of microbial biomass solids containing soluble organics over a shorter residence time of approximately two to three days in the anaerobic bioreactor. Typically, these anaerobic bioreactors consume most, preferably more than 80%, of the organic matter in the feed and produce a biogas product. The biogas product consists mainly of methane (CH ₄ ) and carbon dioxide (CO ₂ ).

This biogas product can be useful for power generation. However, in order to use the biogas for power generation, the biogas usually needs to be treated with one or more removal modules. In addition, as shown below, the use of microbial biomass to produce biogas has proven to be a relatively low-cost use of microbial biomass compared to the possibilities of gasification of microbial biomass.

In addition to the above steps, the wastewater treatment process may also include additional treatment steps after the anaerobic biogenerators. Typically, the treated effluent from anaerobic bioreactors is subjected to additional treatment, including aerobic treatment, struvite recovery, nitrogen recovery, and in some cases reverse osmosis. The clarified water obtained from the wastewater treatment process is suitable for reuse and/or disposal. One suitable way to use this clarified water is to recycle the clarified water to a fermentation process and/or a gasification process.

While the wastewater treatment process can successfully treat the wastewater generated from the fermentation process to produce clarified water, organic metabolites in the wastewater stream often pose several problems. In particular, the treatment of microbial biomass in a wastewater stream by a wastewater treatment process can pose design challenges due to (i) high protein content and therefore high ammonia production during anaerobic digestion and (ii) the large area required for carrying out the wastewater treatment process.

Ammonia is a problem for anaerobic digestion because ammonia is associated with inhibition of methanogenesis during the anaerobic digestion process if it is in high concentrations. Inhibitory concentrations of ammonia have been found to be in the range of 2 to 3 g/l. This threshold value can be significantly exceeded, since the concentration of ammonia can exceed 20 g/l during the fermentation of the separated microbial biomass. Thus, the treatment of microbial biomass in a wastewater treatment process often requires an ammonia stripping process to reduce the ammonia concentration below inhibitory levels.

- 11 041920

The requirement for a large area of the site is a serious problem in areas where land is expensive. Each component of the wastewater treatment process requires a significant amount of space due to the significant volumes that are being processed. For example, an anaerobic bioreactor with a long residence time may in some cases exceed 7000 m ³ .

The inventors have found that these problems can be solved by recycling at least a portion of the microbial biomass to the gasification process. The less microbial biomass that is sent to anaerobic digestion, the less ammonia is produced and therefore the need for the ammonia stripping process is reduced and/or eliminated. In addition, since large volumes of the effluent from the fermentation process are sent to the gasification process, smaller volumes of the effluent are sent to the wastewater treatment process. With smaller volumes of effluent treated in the wastewater treatment process, the required volume and associated site requirements are reduced, making the design more advantageous for areas where land is expensive.

In addition to eliminating the above problems, the recycling of microbial biomass to the gasification process has the following beneficial results: (i) most of the energy contained in the biomass is recovered; (ii) increasing the ratio of H ₂ :CO in the resulting synthesis gas stream; (iii) the content of inorganic substances, metal compounds and alkaline elements in microbial biomass, which usually require additional treatment steps in the wastewater treatment process, are conveniently collected in the gasification process as part of the ash fraction, which already requires disposal, thus reducing the overall volume of waste treatment; and (iv) the nitrogen contained in the biomass will be reacted in the gasifier to N ₂ , NH ₃ and trace HCN, which integrates well with existing removal processes.

The inventors also unexpectedly found an increase in income when recycling biomass to gasification compared to using biomass in biogas production. In particular, the inventors found a 321% increase in revenue when comparing the use of biomass in syngas with the use of biomass in biogas production.

This percentage of income gain is best shown in the table below, which shows the value created by 20 GJ/h of biomass generated by each route.

GJ/h biomass GJ/h product gas GJ/h ethanol Product cost, $/GJ Income, $/h % income growth Biomass cost in $/GJ Anaerobic Digestion for Biogas 20 12 n/a 8 96.0 n/a 4.80 Gasification to produce synthesis gas 20 15 8.25 37.3 307.7 321% 15.39

The calculations presented in the table above compare the cost of converting biomass to biogas through anaerobic digestion and biomass to syngas through gasification. The conversion efficiency in obtaining biogas from biomass through anaerobic digestion is about 60%. The conversion efficiency for producing synthesis gas from biomass through gasification is about 75%, which may vary depending on the gasification technology used. GJ/h product gas is GJ/h biomass multiplied by the corresponding conversion efficiency. GJ/h of ethanol is the GJ/h of product gas multiplied by the gas fermentation conversion efficiency. The conversion efficiency of gas fermentation to produce ethanol is conservatively estimated to be around 55%. With this conversion efficiency, a GJ/h of ethanol was found to be 8.25. The current price of biogas in the absence of renewable incentives ranges from $4 in the US to $10 in the European Union as of November 5, 2018. For the purposes of the analysis, the price of $8 per 1 GJ of biogas (product value of $8/GJ) is used. The price of low-carbon ethanol is currently, as of November 5, 2018, $850/t ethanol in the European Union, $1100/t ethanol in China and $1200/t ethanol in the USA. For the purposes of the analysis, the price of $1000/t of ethanol is used, which is equivalent to $37.30/GJ. Revenue, $/hr is GJ/hr of product gas multiplied by product cost, $/GJ. Specified % Income Growth

- 12 041920 is a comparative value of Revenue, $/h for Anaerobic Digestion to produce biogas compared to Revenue, $/h for Gasification to produce synthesis gas. Biomass cost in $/GJ shows the cost of biomass for the selected process. It is calculated by dividing

Income, $/h per GJ/h of biomass. As shown, the use of biomass to produce synthesis gas through gasification significantly increases both the income and the cost of biomass.

An additional benefit of supplying microbial biomass to the gasification process is that the microbial biomass can help provide additional amounts of synthesis gas that may be required to adequately drive the fermentation process. For example, to feed the syngas required for the ethanol fermentation process to produce 100,000 t/y of ethanol, a gasifier feed rate of about 1200 td/d is required, which is equivalent to 50 td/h based on current design parameters. The biomass produced in a fermentation process of this magnitude is typically between 1000 and 1200 kg/h. This is a significant amount of biomass. The additional quantities of syngas that can be produced by biomass gasification can be particularly useful in situations where the feedstock for the gasifier is limited or where the price of the feedstock is high.

Biomass from the fermentation process may require an additional drying step before being fed into the gasifier to increase the percentage of biomass. Depending on the requirements of the gasifier, the biomass may need to be dried to the point where the biomass is greater than 20% by weight.

However, gasification of biomass with increased moisture content has the additional advantage of increasing the H ₂ :CO ratio in the resulting synthesis gas. At a moisture content of about 15% by weight in the gasification feedstock, the resulting synthesis gas stream has an H2:CO ratio of 1:1. When the moisture content of the gasification feedstock is increased to 40% by weight, the resulting synthesis gas stream has an H ₂ :CO ratio of 2:1. As previously stated, increasing the H2:CO ratio in the synthesis gas stream fed to the fermentation process leads to an increase in the efficiency of the fermentation process.

In order to achieve the above advantages, the present invention recycles one or more of the following effluent streams selected from the group consisting of biogas from a wastewater treatment process, tail gas from a fermentation process, unused synthesis gas from a gasification process, microbial biomass from the fermentation process, microbial biomass from the wastewater treatment process, crude ethanol from the product isolation process, fusel oil from the product isolation process, water depleted of microbial biomass, wastewater from the fermentation process and clarified water obtained in the process of wastewater treatment. One or more of these effluent streams may be sent to the gasification process to produce a synthesis gas stream used in the gasification process as a heating source and/or used in the gasification process to suppress the produced synthesis gas. This synthesis gas stream is preferably suitable for gas fermentation.

In FIG. 1 is a process integration diagram depicting the integration of a gasification process 300, a gas fermentation process 100, a product recovery process 400, and a wastewater treatment process 200 in accordance with one aspect of the present invention. These processes are preferably integrated by using effluents from at least one process as a feedstock source in at least one other process. Preferably, gasification process 300 receives gasification feed 301, which may be any suitable material capable of being gasified to form syngas stream 302. In various cases, the gasification feedstock 301 consists at least in part of sorted and/or unsorted municipal solid waste. In other cases, the gasification feedstock 301 consists at least in part of forestry and/or agricultural waste. In particular embodiments, the gasification feedstock 301 consists of a combination of two or more of the following: sorted municipal solid waste, unsorted municipal solid waste, forestry waste, agricultural waste, at least one effluent from the fermentation process 100, at least one effluent from product recovery process 400; and at least one effluent from wastewater treatment process 200.

Preferably, the gasification process 300 receives the gasification feedstock 301 and produces a synthesis gas stream 302 that is suitable for fermentation in the gas fermentation process 100 . Fermentation process 100 preferably uses this stream as a carbon source to produce one or more products that may be at least partially contained in one or more effluent streams 102, 104. In various cases, the effluent generated from fermentation process 100 is fermentation broth. Preferably, one or more products obtained in the fermentation process 100 are removed and/or separated from the fermentation broth during the product isolation process 400 . Preferably, product recovery process 400 removes one or more products 406 and produces at least one effluent 402, 404, 408 that contains reduced amounts of at least one product. This effluent may be sent via conduit 402 to wastewater treatment process 200 to produce at least one effluent 202 that may be recycled to gasification process 300 and/or fermentation process 100.

In at least one embodiment, the effluent generated from fermentation process 100 is a tail gas generated from fermentation process 100. Preferably, at least a portion of this tail gas is sent via conduit 104 to gasification process 300. At least a portion of the residual gas may be sent via conduit 124 to the gasification process 300 and will be used as part of the gasification feed 301. At least a portion of the residual gas may be directed through conduit 114 to gasification process 300 to suppress syngas stream 302.

In at least one embodiment, the off-gas generated during the fermentation process 100 is a fermentation broth. Preferably, at least a portion of the fermentation broth is sent via conduit 102 to product isolation process 400. In at least one embodiment, the product isolation process 400 separates at least a portion of the microbial biomass produced by the fermentation process 100. In various cases, at least a portion of the microbial biomass that is separated from the fermentation broth is recycled to the fermentation process 100 via conduit 404. In various cases, at least a portion of the microbial biomass that is separated from the fermentation broth is sent via conduit 428 to the gasification process 300. You can use at least part of the microbial biomass as part of the raw material 301 for gasification.

In various cases, at least a portion of the wastewater stream containing the fermentation broth, which may contain microbial biomass, can be sent from the fermentation process 100 directly through the pipeline 104 to the gasification process 300 without being transferred to the process 400 product recovery. At least a portion of the wastewater may be directed through conduit 124 to the gasification process 300 for use as part of the gasification feedstock 301. At least a portion of the fermentation broth may be directed through conduit 114 to gasification process 300 to suppress syngas stream 302.

In cases where the fermentation broth is treated in the product recovery process 400, at least a portion of the microbial biomass-depleted water obtained by removing the microbial biomass from the fermentation broth may be returned to the fermentation process 100 via conduit 404 and/or directed via conduit 408 to process 300 gasification. At least a portion of the water depleted of microbial biomass may be sent through pipeline 428 to the gasification process 300 for use as part of the gasification feedstock 301. At least a portion of the water depleted in microbial biomass may be directed through conduit 418 to suppress flow 302 of synthesis gas. In addition, at least a portion of the effluent generated from the product separation process 400 may be directed via conduit 402 to the wastewater treatment process 200 . Preferably, the effluent generated from product recovery process 400 includes reduced amounts of product and/or microbial biomass.

Preferably, the wastewater treatment process 200 receives and treats the effluent from one or more processes to produce clarified water. This clarified water may be directed through conduit 202 to one or more processes. In certain instances, at least a portion of the clarified water is sent via conduit 212 to the fermentation process. At least a portion of the clarified water may be sent via conduit 232 to gasification process 300 to be used as part of the gasification feedstock 301. At least a portion of the clarified water may be directed through conduit 222 to gasification process 300 to suppress syngas stream 302.

In certain cases, the wastewater treatment process 200 generates microbial biomass as part of the treatment process. At least a portion of this microbial biomass may be directed through conduit 232 to gasification process 300. Preferably, the gasification process 300 uses at least a portion of the microbial biomass generated from the wastewater treatment process 200 as part of the gasification feedstock 301.

The wastewater treatment process 200 produces biogas as a by-product of the microbial biomass treatment. At least a portion of this biogas may be directed through pipeline 202 to gasification process 300 . In certain instances, at least a portion of the biogas is sent via pipeline 232 to the gasification process 300, which will be used as part of the gasification feedstock 301. At least a portion of the biogas may be directed through conduit 222 to gasification process 300 to suppress syngas flow 302 .

Preferably, the gasification process 300 receives one or more effluent streams from the fermentation process 100, product recovery process 400, and/or wastewater treatment process 200 to form a syngas stream 302. This synthesis gas stream 302 is preferably suitable

- 14 041920 for use as raw material for the gas fermentation process 100.

To be suitable for use as feedstock for gas fermentation process 100, syngas stream 302 should preferably have the desired composition. In specific cases, the synthesis gas 302 obtained from the gasification process 300 contains one or more components that must be removed and/or converted.

Typical components found in syngas stream 302 that may need to be removed and/or converted include, but are not limited to, sulfur compounds, aromatics, alkynes, alkenes, alkanes, olefins, nitrogen compounds, phosphorus compounds, solids, solids , oxygen, halogenated compounds, silicon compounds, carbonyls, metals, alcohols, esters, ketones, peroxides, aldehydes, esters and resins. These components may be removed using one or more removal processes.

In FIG. 2 shows the process integration diagram shown in FIG. 1 further including a removal process 500 between the gasification process 300 and the gas fermentation process 100, in accordance with one aspect of the present invention.

Preferably, the removal process 500 includes one or more of the following modules: a hydrolysis module, an acid gas removal module, a deoxygenation module, a catalytic hydrogenation module, a particle removal module, a chloride removal module, a tar removal module, and a hydrogen cyanide purification module.

When the removal process 500 is activated, at least a portion of the synthesis gas 302 produced in the gasification process 300 is sent to the removal process 500 to remove and/or convert at least a portion of at least one component present in the synthesis gas stream 302. Preferably, the removal process 500 brings the components to acceptable levels to obtain a purified stream 502 suitable for fermentation in the fermentation process 100.

In various cases, the removal process 500 includes two or more removal modules selected from the group consisting of a hydrolysis module, an acid gas removal module, a deoxygenation module, a catalytic hydrogenation module, a particle removal module, a chloride removal module, a tar removal module, and a hydrogen cyanide purification module. . In certain instances, one or more of these removal modules are used to remove one or more components from the gas stream that may adversely affect downstream processes, such as downstream fermentation process 100 and/or downstream removal modules. involved in the removal process 500 .

One or more of the components removed and/or converted in the removal process 500 may be introduced and/or concentrated by gasification of the microbial biomass. In certain cases, the removal process 500 removes ammonia (NH3) and/or hydrogen cyanide (HCN). This ammonia and/or hydrogen cyanide can be introduced and/or concentrated when the microbial biomass is gasified in the gasification process 300 . Ammonia and hydrogen cyanide can be produced from the nitrogen contained in the microbial biomass, which during the gasification process 300 will react to convert to N2, NH3 and traces of HCN.

Typically, the synthesis gas stream fed to the fermentation process 100 is gaseous. However, the synthesis gas stream can also be provided in alternative forms. For example, the synthesis gas stream may be dissolved in a synthesis gas-saturated liquid, which may then be fed to the fermentation process 100. As a further example, synthesis gas may be adsorbed onto a solid support.

Preferably, the fermentation process 100 uses C1-fixing microorganisms to ferment the synthesis gas stream 302 and produce one or more products. The C1-fixing microorganism in the fermentation process 100 is typically a carboxydotrophic bacterium. In specific embodiments, the carboxydotrophic bacterium is selected from the group consisting of Moorella, Clostridium, Ruminococcus, Acetobacterium, Eubacterium, Butyribacterium, Oxobacter, Methanosarcina, Methanosarcina, and Desulfotomaculum. In various embodiments, the carboxydotrophic bacterium is Clostridium autoethanogenum.

In certain instances, one or more processes are integrated by using at least a portion of at least one effluent from one process as a heat source for at least one other process.

In FIG. 3 is a process integration diagram depicting the integration of a gasification process 300, a gas fermentation process 100, a product recovery process 400, and a wastewater treatment process 200 in accordance with one aspect of the present invention. In various cases, these processes are integrated by using at least one effluent from at least one process as a heat source in at least one other process. In particular embodiments, the biogas generated from the wastewater treatment process 200 is used as a heat source for one or more processes. Preferably, at least a portion of the biogas generated in the wastewater treatment process 200 is used as a heating source for the gasification process 300. In certain cases, the gasification process 300 uses

- 15 041920 at least a portion of the biogas generated in the wastewater treatment process 200 to melt at least a portion of the slag generated in the gasification process 300. In one or more embodiments, at least a portion of the biogas generated in the wastewater treatment process 200 is used as a heat source for the gas fermentation process 100. In one or more embodiments, at least a portion of the biogas generated in the wastewater treatment process 200 is used as a heat source for the product recovery process 400 . In one or more embodiments, at least a portion of the biogas generated in the wastewater treatment process 200 is used as a heat source for the removal process 500.

In various cases, the biogas stream generated in the wastewater treatment process 200 is sent via conduit 202 to at least one removal process 600 before being sent to one or more processes. Preferably, the removal process 600 reduces the amount of at least one sulfur compound in the biogas stream.

When the removal process 600 is activated after the wastewater treatment process 200, at least a portion of the biogas produced in the wastewater treatment process 200 is sent to the removal process 600 to remove and/or convert at least a portion of at least one component present in the biogas stream . Preferably, the removal process 600 adjusts the components to acceptable levels to produce a purified stream 642, 612, 622, and/or 632 suitable for use in a subsequent one or more processes 400, 100, 500, and/or 300, respectively.

In specific embodiments, the tail gas generated from the fermentation process 100 is used as a heat source for one or more processes. Preferably, at least a portion of the residual gas generated in the fermentation process 100 is used as a heating source for the gasification process 300. In certain instances, the gasification process 300 uses at least a portion of the tail gas generated from the fermentation process 100 to melt at least a portion of the slag produced from the gasification process 300. In one or more embodiments, at least a portion of the tail gas generated from fermentation process 100 is used as a heat source for product isolation process 400. In various cases, the tail gas produced in the fermentation process 100 is sent to at least one removal process before being sent to one or more processes.

In particular embodiments, unused synthesis gas generated from gasification process 300 is used as a heat source for one or more processes. Preferably, at least a portion of the unused synthesis gas generated in the gasification process 300 is used as a heat source for the gasification process 300. In some cases, the gasification process 300 uses at least a portion of the unused synthesis gas generated in the gasification process 300 to melt at least a portion of the slag produced in the gasification process 300. In one or more embodiments, at least a portion of the unused synthesis gas generated in the gasification process 300 is used as a heat source for the product recovery process 400. In various cases, unused synthesis gas produced in gasification process 300 is sent to at least one removal process before being sent to one or more processes.

The fermentation process 100 preferably produces a variety of products. These products may preferably be separated by a product isolation process 400 . In various cases, at least a portion of at least one of the products obtained in the fermentation process 100 can be used as a source for one or more processes. In certain instances, at least a portion of the ethanol produced in product isolation process 400 is used as a heat source for gasification process 300. Preferably, the ethanol used as the heating source for one or more of the processes is crude ethanol that does not meet fuel ethanol specifications. In certain cases, the gasification process 300 uses at least a portion of the crude ethanol produced in the product isolation process 400 to melt at least a portion of the slag produced in the gasification process 300.

In certain cases, the fermentation process 100 produces fusel oil. This fusel oil may be recovered from the product recovery process 400 by any suitable means. For example, in the fractionating column of a distillation plant. In at least one embodiment, at least a portion of the fusel oil produced in product isolation process 400 is used as a heat source for one or more processes. In certain instances, at least a portion of the fusel oil produced in the product isolation process 400 is used as a heat source for the gasification process 300. Preferably, the gasification process 300 uses at least a portion of the fusel oil obtained from the product recovery process 400 to melt at least a portion of the slag obtained from the gasification process 300.

All references, including publications, patent applications, and patents, cited herein are incorporated herein by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and set forth herein in

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Claims (4)

in full. In this specification, reference to any prior art does not constitute and should not be construed as an admission that such prior art is part of the public knowledge of the art in any country. The use of terms in the singular and similar references in the context of the description of the present invention (especially in the context of the following claims) should be considered to include both the singular and the plural, unless otherwise specified herein or clearly contrary to the context. The terms containing, having, including, and covering are to be considered as non-limiting terms (i.e., meaning including, without limitation) unless otherwise noted. The term consisting essentially of limits the scope of the composition, process or method to the specified materials or steps, or that does not significantly affect the basic and new characteristics of the composition, process or method. The use of an alternative (eg, or) should be understood to mean one, both, or any of the above combinations of alternatives. As used herein, the term about means ±20% of a given range, value, or structure, unless otherwise noted. The listing of ranges of values in this document is merely intended to be used as a shorthand way of separately referring to each individual value falling within that range, unless otherwise noted in this document, and each individual value is included in this specification as if it were given separately. in this document. For example, any concentration range, percentage range, ratio range, integer range, size range, or thickness range should be understood to include the value of any integer within the range given and, if appropriate, its fractions (e.g., one tenth and one hundredth of an integer ), unless otherwise specified. All of the methods described herein may be performed in any suitable order, unless otherwise indicated herein or otherwise clearly contradicts the context. The use of any possible examples or introductory words before an example (eg, such as) provided herein is merely intended to better illuminate the present invention and does not limit the scope of the present invention unless otherwise stated. None of the expressions given in this description, should not be understood as an indication of any unclaimed element as necessary for the practical implementation of this invention. This document describes the preferred embodiments of the present invention. Variations on these preferred embodiments will become apparent to those skilled in the art upon reading the above description. The inventors expect those skilled in the art to make use of such variations as needed, and the inventors expect the present invention to be practiced otherwise than specifically described herein. Accordingly, the present invention includes all modifications and equivalents of the subject matter set forth in the appended claims, as permitted by applicable law. In addition, any combination of the elements described above, in all their possible variations, is covered by the present invention, unless otherwise indicated herein or otherwise clearly contradicts the context. CLAIM 1. An integrated method, including: a) sending the carbonaceous material to a gasification process to produce a syngas stream containing CO and H ₂ ; b) directing the synthesis gas stream into a fermentation process, including a bioreactor containing a C1-fixing bacterium in a liquid nutrient medium, to obtain an effluent stream containing at least one fermentation product and microbial biomass; c) directing the effluent to a product recovery zone to produce a microbial biomass-containing stream, a product stream containing at least a portion of at least one fermentation product, a by-product stream containing fusel oil, and a wastewater stream containing microbial biomass; And d) directing at least a portion of at least one stream selected from a product stream, a by-product stream, a microbial biomass-containing stream, a wastewater stream, or combinations thereof, into the gasification process. 2. The method according to claim 1, characterized in that the product stream contains crude ethanol and at least a portion of the product stream containing crude ethanol is sent to a gasifier for use as a heating source. 3. The method according to claim 2, characterized in that at least a portion of the product stream containing crude ethanol is used as a heat source for melting at least a portion of the slag obtained from the gasification process. 4. The method according to claim 1, characterized in that at least part of the wastewater flow is sent to -