1. A method, comprising:

a. treating a syngas stream from a gasification process or industrial waste gas by adsorbing components comprising at least one of hydrocarbons, oxygenates, sulfur compounds, nitrogen compounds, or any combination thereof on an adsorbent, and generating a treated stream;

b. fermenting at least a portion of the treated stream in a bioreactor using a microorganism to produce an effluent comprising at least one product and a tail gas stream comprising at least carbon dioxide;

c. regenerating the adsorbent by at least partially desorbing the component using at least a portion of the tail gas stream to provide an enriched tail gas stream comprising the carbon dioxide and desorbed component; and

d. utilizing the enriched tail gas stream in at least one of:

i. combusting in a steam boiler to produce steam;

generating power;

recycling to the gasification process; or

Passing to a product recovery zone.

2. The method of claim 1, wherein the tail gas further comprises methane, carbon monoxide, and hydrogen.

3. The method of claim 1, wherein the microorganism is one or more C1 immobilized microorganisms.

4. The method according to claim 3, wherein the C1-immobilized microorganism is selected from the group consisting of Mueller, Clostridium, Ruminococcus, Acetobacter, Eubacterium, Butyribacterium, Acetobacter, Methanosarcina, and Thielenteroides.

5. The method of claim 1, wherein the steam is high pressure steam.

6. The method of claim 1, further comprising employing the steam to: distillation of fermentation product, operation of adsorption coolers, steam driven compression, evaporation of waste water, drying of biomass, in situ steam operation, in situ cleaning operation, drying of raw materials, steam driven raw material conveyors, heating of buildings, power generation, and power generation to drive compressors of the fermentation process.

7. The method of claim 1, wherein the industrial waste gas is from a process selected from the group consisting of: ferrous metal product manufacture, non-ferrous metal product manufacture, petroleum refining, electricity production, carbon black production, paper and pulp manufacture, ammonia production, methanol production, coke manufacture, and any combination thereof, and/or the syngas stream is from the following process: gasification of coal, gasification of refinery residues, gasification of biomass, gasification of lignocellulosic materials, black liquor gasification, gasification of municipal solid waste, gasification of industrial solid waste, gasification of sewage, gasification of sludge from wastewater treatment, reforming of natural gas, reforming of biogas, reforming of landfill gas, or any combination thereof.

8. The method of claim 1, wherein the generated power is cogeneration or direct generation.

9. The method of claim 1, wherein the tail gas stream is compared to the syngas stream from a gasification process or the industrial waste gas,

a. is rich in N₂；

b. Is rich in CO₂；

c. Impurity depletion; or

Any combination of (a), (b), or (c).

10. The method of claim 9, wherein desorbing the component using at least a portion of the tail gas stream is improved as compared to desorbing the component using a syngas stream.

11. A method, comprising:

a. gasifying a gasification feedstock to produce a synthesis gas comprising at least carbon monoxide, hydrogen, water and tar;

b. cooling the syngas by condensation to separate water and at least one tar and provide a water and at least one tar-depleted remainder of the syngas;

c. disposing of the at least one tar by:

i. combusting the at least one tar using a flame produced from combustion of a fuel gas, natural gas, syngas, tail gas from a gas fermentation process, or any combination thereof; or

Passing the at least one tar to a wastewater treatment process; and

d. fermenting at least a portion of the remaining portion of the syngas in a bioreactor using a microorganism to produce an effluent comprising at least one product.

12. The method of claim 11, further comprising removing at least a second tar from the syngas by adsorption using an adsorbent.

13. The method of claim 12, wherein the fermentation also produces the tail gas.

14. The method of claim 13, further comprising using the tail gas to regenerate the adsorbent.

15. The method of claim 14, further comprising generating steam using the tail gas after regenerating the sorbent.

16. The method of claim 15, further comprising generating electricity using the steam.

17. The method of claim 16, further comprising using the electricity to drive a compressor of the fermenting step.

18. An apparatus, comprising:

a. an adsorption unit containing an adsorbent;

b. a bioreactor in fluid communication with the adsorption unit;

c. a tail gas conduit in fluid communication with the bioreactor and the adsorption unit;

d. an enrichment tail gas utilization unit comprising at least one of:

i. a vaporizer in fluid communication with the adsorption unit;

a steam generating unit;

a power production unit; or

A product recovery unit in fluid communication with the bioreactor; and

e. an enriched tail gas conduit in fluid communication with the adsorption unit and the enriched tail gas utilization unit.

19. The apparatus of claim 18, further comprising a steam conduit in fluid communication with the steam generation unit and a power generation system.

20. The apparatus of claim 19, further comprising a compressor in electrical communication with the power generation system and in fluid communication with the bioreactor.

21. The plant of claim 18, wherein the power production unit is a cogeneration power production unit or a direct power production unit.

22. The apparatus of claim 18, further comprising a feed conduit in fluid communication with the adsorption unit.

Background

As the world population increases, the waste generated by this population becomes an increasingly interesting problem. One solution for waste disposal is gasification. Gasification is a process of converting carbonaceous material based on organic or fossil fuels into synthesis gas comprising carbon monoxide, carbon dioxide and hydrogen. Gasification advantageously both reduces the amount of waste in the landfill and produces product syngas, which can be converted to useful products by one or more subsequent processes.

The syngas produced from gasification can be utilized by a number of processes including the fischer-tropsch process. The fischer-tropsch process provides for the catalytic hydrogenation of carbon monoxide to produce a variety of products, including hydrocarbons, alcohols, or other oxygenated hydrocarbons. However, the catalytic bed in the fischer-tropsch process is particularly sensitive to the various components that may be present in the synthesis gas stream (depending on the gasification feedstock). One such component is sulfur. If sulfur is not removed from the synthesis gas stream prior to sending the synthesis gas stream to the fischer-tropsch process, the sulfur may deactivate the catalyst required for the fischer-tropsch reaction. Therefore, extensive gas purification techniques are generally required in order to obtain a gas suitable for the fischer-tropsch process.

An alternative to the fischer-tropsch process is gas fermentation. Gas fermentation biologically immobilizes a gas (including syngas) into one or more products. Gas fermentation has several advantages over the fischer-tropsch process. First, the fischer-tropsch process utilizes high temperatures (150 ℃ to 350 ℃), elevated pressures (30 bar) and heterogeneous catalysts such as cobalt, ruthenium and iron. In contrast, gas fermentation occurs at about 37 ℃ and is typically carried out at atmospheric pressure, which saves significant energy and cost relative to the fischer-tropsch process. In addition, the Fischer-Tropsch process requires H in the syngas₂The CO ratio is relatively fixed, around 2:1, whereas gas fermentation is able to accept and utilize a wide variety of substrates with different H2: CO ratios.

Gasification converts biomass or municipal waste by partial oxidation into a gaseous mixture of syngas containing carbon monoxide, hydrogen, methane, nitrogen, water vapor, carbon dioxide and tars. Biomass-derived syngas contains, inter alia, a high concentration of tarry compounds and particulates that should be removed from the syngas. Tars generally comprise a range of hydrocarbons and oxygenates. Examples include aromatic compounds, polyaromatic compounds, furan backbone structures, where aliphatic and oxygenated functional groups such as acids, aldehydes, ketones and alcohols are attached to the backbone. It is envisaged that the industrial gas may also contain tars, depending on the source of the industrial gas.

There remains a need to effectively remove tar from industrial gases or gasification-derived syngas before the gas can be used in downstream processes. Furthermore, there is still a need for a higher level of integration between gasification and gas fermentation operations in order to use the waste stream of one operation for the whole system in the most beneficial way. An unexpectedly beneficial use of the tail gas from a gas fermentation operation is to employ at least a portion of the tail gas to regenerate an adsorbent used to separate at least one tar from syngas prior to the syngas being used as a feed to the gas fermentation operation. The integration level can be further improved by burning the tail gas, which is enriched with tar and has a higher calorific value after the tar has been desorbed, in a steam boiler to generate steam. There is a surprising amount of residual energy in the tar-rich tail gas, and thus a surprising amount of steam is generated. Integration can be further integrated by utilizing the steam to generate power for the compressor used in the gas fermentation operation. Other options include generating power such as in a gas engine or gas turbine.

Disclosure of Invention

The present disclosure relates to a method comprising: treating a synthesis gas stream from a gasification process or industrial gas by adsorbing at least one hydrocarbon and/or oxygenate on an adsorbent and generating a treated stream; fermenting at least a portion of the treated stream in a bioreactor using a microorganism to produce an effluent comprising at least one product and a tail gas stream; regenerating the adsorbent by desorbing at least one hydrocarbon or oxygenate using at least a portion of the tail gas stream to provide an enriched tail gas stream further comprising the desorbed at least one hydrocarbon or oxygenate; and utilizing at least a portion of the enriched tail gas in at least one of: combusting in a steam boiler to produce steam; generating power; or recycled to the gasification process.

The present disclosure also relates to an apparatus, comprising: an adsorption unit containing an adsorbent; a vaporizer in fluid communication with the adsorption unit; a bioreactor in fluid communication with the adsorption unit; a tail gas conduit in fluid communication with the bioreactor and the adsorption unit; a steam generation unit; and an enriched tail gas conduit in fluid communication with the adsorption unit and the steam generation unit. The apparatus may further include a steam conduit in fluid communication with the power generation system. The apparatus may further include a compressor in electrical communication with the power generation system and in fluid communication with the bioreactor.

In one embodiment, the fermentation process utilizes one or more C1 immobilized microorganisms suitable for fermenting a C1 containing gaseous substrate, such as syngas produced by gasification. In various embodiments, the C1 immobilized microorganism is selected from the group consisting of: moorella (Moorella), Clostridium (Clostridium), Ruminococcus (Ruminococcus), acetobacter (acetobacter), Eubacterium, butyrobacterium (butyrobacterium), acetobacter (oxobacterium), Methanosarcina (Methanosarcina), and sulfoenterobacter (desulfomobacterium). The microorganism may be a member of the genus clostridium. In some cases, the microorganism is Clostridium autoethanogenum.

In various embodiments, the gasification feedstock is municipal solid waste, agricultural waste, microbial biomass, or any combination thereof. The gasification feedstock is dried in a dryer and then gasified to produce a syngas stream. At least a portion of the syngas stream is passed to a fermentation process to produce one or more products and possibly at least one byproduct. In some embodiments, the microbial biomass produced from the fermentation process is passed to the gasification operation as a feedstock for gasification.

In some embodiments, substantially all of the microbial biomass produced by the fermentation process is recycled to the fermentation process after product recovery, treated by a wastewater treatment process, and/or sent to a gasification process to produce syngas. In certain instances, 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%, or substantially all of the microbial biomass from the fermentation process.

In some embodiments, the microbial biomass produced from the wastewater treatment process is sent to a gasification process. Microbial biomass generated from a wastewater treatment process may be at least partially recovered from an anaerobic digester process in the wastewater treatment process. In each case, at least a portion of the microbial biomass from the wastewater treatment process is dried before being passed to the gasification process. In some cases, substantially all of the microbial biomass from the wastewater treatment process is dried before being passed to the gasification process.

In a particular embodiment, at least a portion of the microbial biomass-depleted water from the fermentation process is sent to the gasification process. In each case, the water depleted in microbial biomass is sent to a gasification process to increase the H in the syngas stream₂The ratio of CO. Preferably, at least a portion of the microbial biomass-depleted water is sent to a gasification process to convert H in the syngas stream₂The CO ratio is increased to at least 2:1, at least 3:1, or at least 4: 1. Passing the microbial biomass-depleted water to a gasification process (wherein H in the syngas stream₂I.e. increased CO ratio) may lead to an increased selectivity for ethanol produced by the gas fermentation process, a decreased selectivity for microbial biomass production, a decreased water consumption for the fermentation reaction and/or a decreased blowdown stream from the wastewater treatment process.

In particular embodiments, at least a portion of the wastewater produced from the fermentation process is sent to the gasification process. The wastewater may comprise one or more products and/or by-products, including but not limited to microbial biomass. In each case, the wastewater generated from the fermentation process is sent to a gasification process to increase the H in the syngas stream₂The ratio of CO. Preferably, at least a portion of the wastewater generated from the fermentation process is sent to a gasification process to convert H in the syngas stream₂The CO ratio is increased to at least 2:1, at least 3:1, or at least 4: 1. The wastewater generated from the fermentation process is sent to a gasification process (where H in the syngas stream is₂I.e. increased CO ratio) may lead to an increased selectivity for ethanol produced by the gas fermentation process, a decreased selectivity for microbial biomass production, a decreased water consumption for the fermentation reaction and/or a decreased blowdown stream from the wastewater treatment process.

In particular embodiments, at least a portion of the clarified water from the wastewater treatment process is sent to a gasification process. In each case, clarified water from a wastewater treatment process is sent to a gasification process to increase H in a syngas stream₂The ratio of CO. Preferably, of clarified water from a wastewater treatment processAt least a portion of which is sent to a gasification process to convert H in a syngas stream₂The CO ratio is increased to at least 2:1, at least 3:1, or at least 4: 1. Sending clarified water from the wastewater treatment process to a gasification process (wherein H in the syngas stream₂I.e. increased CO ratio) may lead to an increased selectivity for ethanol produced by the gas fermentation process, a decreased selectivity for microbial biomass production, a decreased water consumption for the fermentation reaction and/or a decreased blowdown stream from the wastewater treatment process.

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

In certain instances, at least a portion of the at least one effluent is injected into a syngas stream produced by the gasification process to reduce the temperature of the syngas stream. Preferably, the effluent injected into the synthesis gas stream produced by the gasification process is selected from the group consisting of: water depleted in microbial biomass, wastewater produced from fermentation processes, and clarified water from wastewater treatment plants. Preferably, the temperature of the syngas stream is reduced by at least 100 degrees celsius. In at least one embodiment, the syngas stream exiting the gasification process is between 800 ℃ and 1200 ℃. Preferably, the temperature of the synthesis gas stream is reduced to a temperature range suitable for further gas treatment and/or fermentation. In each case, the injection of the at least one effluent into the syngas stream is accomplished to remove the at least one particulate from the syngas stream.

In some cases, the syngas stream is partially quenched. Preferably, the synthesis gas stream is partially quenched by injecting one or more effluents into the synthesis gas stream, the one or more effluents being selected from the group consisting of: microbial biomass depleted water, from fermentation processThe resulting wastewater and clarified water from wastewater treatment plants. In various embodiments, the partial quenching of the syngas stream reduces the temperature of the syngas stream to 700 ℃ to 800 ℃. In various embodiments, this temperature reduction requires approximately 1.2 tons of process water per 10,000Nm, starting at 1000 deg.C³The synthesis gas is quenched. 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%, or substantially all of the process water is replaced by injecting one or more effluents into the synthesis gas stream.

In some cases, the syngas stream is fully quenched. Preferably, the synthesis gas stream is fully quenched by injecting one or more effluents into the synthesis gas stream, the one or more effluents being selected from the group consisting of: water depleted in microbial biomass, wastewater produced from fermentation processes, and clarified water from wastewater treatment plants. In various embodiments, the complete quenching of the syngas stream reduces the temperature of the syngas stream to less than 300 ℃. In various embodiments, this temperature reduction requires approximately 4 tons of process water per 10,000Nm, starting at 1000 deg.C³The synthesis gas is quenched. 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%, or substantially all of the process water is replaced by injecting one or more effluents 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. The biogas may comprise one or more components selected from the group consisting of: methane, carbon dioxide, carbon monoxide, ammonia, and sulfur compounds. In each case, this sulfur compound is hydrogen sulfide. In at least one embodiment, the biogas comprises about 60% methane and about 40% carbon dioxide. In at least one embodiment, the biogas comprises 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 heating source. Preferably, at least a portion of the biogas generated from the wastewater treatment process is used as a heating source by the gasification process. In each case, at least a portion of the biogas sent to the gasification process is used as a heating source for melting at least a portion of the slag produced by the gasification process. In one or more embodiments, biogas from the wastewater treatment process is sent to a removal process before being sent to the gasification process. In various instances, 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 the biogas stream is sent to the gasification process.

In particular embodiments, at least a portion of the methane in the biogas is reformed to CO and H when gasified by a gasification process₂. In each case, the methane reacts with the moisture contained in the syngas to produce carbon monoxide and hydrogen.

In one embodiment, at least a portion of the tail gas generated from the fermentation process, unused syngas generated from the gasification process, crude ethanol from the product recovery process, and/or fusel oil from the product recovery process is used as the heating source. Preferably, at least a portion of at least one of these effluents is used as a heating source by the gasification process. In each case, at least a portion of at least one of these effluents is sent to the gasification process to be used as a heating source for melting at least a portion of the slag produced by the gasification process. In one or more embodiments, these effluents are treated by a removal process before being sent to the gasification process. In various instances, 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 effluent.

In addition to passing 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 from the wastewater treatment process may also be passed to the fermentation process. In certain instances, substantially all of the clarified water from the wastewater treatment process is recycled to the gasification process and/or the fermentation process. In certain instances, the gasification process receives at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or substantially all of the clarified water from the wastewater treatment process. In certain instances, the fermentation process receives at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or substantially all of the clarified water from the wastewater treatment process.

Preferably, the fermentation process utilizes at least a portion of the syngas from the gasification process to produce one or more fuels or chemicals. At least one of the products produced by the fermentation process may be selected from the group comprising: ethanol, acetate, butanol, butyrate, 2, 3-butanediol, 1, 3-butanediol, lactate, butene, butadiene, methyl ethyl ketone, ethylene, acetone, isopropanol, lipids, 3-hydroxypropionate salts, terpenes (including but not limited to isoprene), fatty acids, 2-butanol, isobutylene, isobutanol, 1, 2-propanediol, 1-propanol, and C6-C12 alcohols.

In one or more embodiments, at least a portion of the microbial biomass produced by the fermentation process can be converted to Single Cell Protein (SCP).

In each case, at least a portion of the one or more fuels or chemicals is sent to a secondary conversion process. Preferably, the secondary conversion process further converts at least a portion of the one or more fuels or chemicals to at least one component of diesel fuel, jet fuel, gasoline, propylene, nylon 6-6, rubber, and/or resin.

In one or more embodiments, the syngas from the gasification process is sent to a removal process before being sent to the fermentation process. In various instances, the removal process includes one or more removal modules that are capable of removing, converting, and/or reducing the amount of microbial inhibitors and/or catalyst inhibitors contained in the syngas stream.

Preferably, the at least one component removed, converted and/or reduced in the synthesis gas stream by the removal process is selected from the group comprising: sulfur compounds, aromatics, alkynes, alkenes, alkanes, alkenes, nitrogen compounds, phosphorous compounds, particulates, solids, oxygen, halogenated compounds, silicon-containing compounds, carbonyl compounds, metals, alcohols, esters, ketones, peroxides, aldehydes, ethers, and tars.

Preferably, the removal process comprises at least one removal module selected from the group comprising: the device comprises a hydrolysis module, an acid gas removal module, a deoxidation module, a catalytic hydrogenation module, a particle removal module, a chloride removal module, a tar removal module and a hydrogen cyanide polishing module. In various instances, the removal process includes at least two removal modules.

The invention may also provide for an increase and/or decrease in the pressure of the syngas stream at one or more points in the process.

Drawings

Figure 1 shows a process integration scheme depicting the integration of a gasification process, a gas fermentation process, a product recovery process, and a wastewater treatment process, wherein tail gas from the gas fermentation process is used as a purge gas for an adsorption unit on a syngas stream, and the enriched tail gas is directed to a steam boiler to produce high pressure steam which is then used to drive a compressor of the gas fermentation operation, according to one embodiment of the invention.

FIG. 2 shows the process integration scheme from FIG. 1, further including a removal process between the gasification process and the gas fermentation process, according to an embodiment of the invention.

FIG. 3 shows the process integration scheme from FIG. 2, further including a removal process following the wastewater treatment process, according to one embodiment of the invention.

Figure 4 shows a process integration scheme depicting the integration of a gas fermentation process, a product recovery process, and a wastewater treatment process, in which off-gas from the gas fermentation process is used as a purge gas for an adsorption unit on a feed stream, and the enriched off-gas is directed to a steam boiler to produce high pressure steam which is then used to drive a compressor to feed the gas fermentation operation, according to one embodiment of the invention.

FIG. 5 illustrates one embodiment of the generation of syngas using industrial waste gas as a substrate or C1 carbon source without gasification of the material, wherein the enriched tail gas in the line is directed to a power generation unit. Fig. 5 also shows an alternative embodiment in which the enriched tail gas is directed to a process recovery process and unit, for example to dry the product.

FIG. 6 illustrates an embodiment using a gasifier to generate syngas as a substrate or C1 carbon source, wherein the enriched tail gas is directed to a power generation unit. Fig. 6 also shows an alternative embodiment in which the enriched tail gas is directed to a product recovery process and unit, for example to dry the product.

Detailed Description

The present disclosure describes the integration of a gasification process and a fermentation process and optionally a wastewater treatment process. The syngas from the gasification process is passed through an adsorption unit to remove at least one tar, such as hydrocarbons or oxygenates. For ease of description, tar, as used herein, is intended to include sulfur compounds and nitrogen compounds as well as hydrocarbons and oxygenates. Off-gas from the fermentation process is recycled to the adsorption unit to regenerate the adsorbent. The tail gas enriched in desorbed tars is passed to a steam generating unit to generate steam. The steam may be used for a variety of purposes, such as one or more compressors for the gas fermentation process. A number of unexpected benefits to the efficiency and synergistic effects of integrated gasification and gas fermentation processes are realized. Typically, nitrogen is used to desorb tars and other impurities from the adsorbent. This technology requires the production and storage of nitrogen at a cost, followed by large amounts of contaminated nitrogen that must now be treated, along with a lean tail gas stream having a low energy value. An alternative is to use the treated syngas to regenerate the adsorbent, so the yield loss can be large. By using the tail gas as a purge gas for the adsorption unit, these costs and challenges are avoided.

The terms "increased efficiency", "increased efficiency" and the like, when used in connection with a fermentation process, include, but are not limited to: increasing one or more of the growth rate, growth rate at elevated product concentration, and/or product production rate of a microorganism catalyzing the fermentation, increasing the volume of desired product produced per volume of substrate consumed, increasing the production rate or level of desired product produced, increasing the relative proportion of desired product produced compared to other byproducts of the fermentation, reducing the amount of water consumed by the process, and reducing the amount of energy utilized by the process.

The terms "increased efficiency," "increased efficiency," and the like, when used in connection with a gasification process, include, but are not limited to: increasing the amount of syngas produced by the process, decreasing the amount of water supply utilized by the process, optimizing the syngas stream for gas fermentation, decreasing greenhouse gas emissions, and decreasing the amount of energy (including but not limited to external fuel) utilized by the process.

The terms "increased efficiency", and the like, when used in connection with a wastewater treatment process, include, but are not limited to: reducing the residence time of water in the process, increasing the utilization of the biogas generated by the process, reducing the amount of effluent sent to a wastewater treatment process, reducing the volume requirements of the process, reducing the need for ammonia separation by the process, and reducing the amount of energy utilized by the process.

The substrate and/or C1 carbon source may be an off-gas obtained as a by-product of an industrial process, but may also be an off-gas from some other source, such as an off-gas from automobile exhaust or biomass gasification. In certain embodiments, the industrial process is selected from: ferrous metal product manufacturing (such as steel mill manufacturing), non-ferrous metal product manufacturing, petroleum refining, coal gasification, power production, carbon black production, ammonia production, methanol production, and coke manufacturing. In these embodiments, the substrate and/or C1 carbon source may be captured from the industrial process using any convenient method and then vented to the atmosphere. The term "industrial gas" is intended to include those substrates from industrial processes.

The terms "fermentation", "gas fermentation", and the like should be construed as a process that receives one or more substrates (such as syngas produced by gasification) and produces one or more products by utilizing one or more C1-immobilized microorganisms. Preferably, the fermentation process comprises the use of one or more bioreactors. The fermentation process may be described as "batch" or "continuous". "batch fermentation" is used to describe such a fermentation process: wherein the bioreactor is filled with raw materials (e.g. carbon source) together with microorganisms, wherein the product remains in the bioreactor until the fermentation is completed. In a "batch" process, the product is extracted after the fermentation is completed and the bioreactor is cleaned before the next "batch" is started. "continuous fermentation" is used to describe a fermentation process: wherein the fermentation process is extended for a longer period of time and products and/or metabolites are extracted during the fermentation. Preferably, the fermentation process is continuous.

The term "wastewater treatment" or the like should be construed as a process of separating components from an effluent from a fermentation process to produce clarified water. Wastewater treatment processes may include, but are not limited to, one or more anaerobic digesters with different residence times, and one or more ammonia stripping processes.

The terms "gasification" and the like should be construed to convert organic and/or fossil fuel based carbonaceous materials to carbon monoxide (CO), hydrogen (H)₂) And carbon dioxide (CO)₂) The process of (1). The gasification process may include a variety of technologies including, but not limited to, a counter-current fixed bed gasifier, a co-current fixed bed gasifier, a fluidized bed reactor, an entrained flow gasifier, and a plasma gasifier. The gasification process may utilize any feed that can produce a syngas stream. The term "gasification process" encompasses the gasifier itself along with unit operations associated with gasification, including heating sources for the gasifier and syngas quenching processes.

"syngas stream," "syngas stream," and the like refer to the gaseous substrate exiting the gasification process. The synthesis gas stream should consist mainly of carbon monoxide (CO), hydrogen (H)₂) And carbon dioxide (CO)₂) And (4) forming. The composition of the synthesis gas stream may vary significantly depending on the feedstock and gasification process involved; however, a typical composition of syngas includes thirty to sixty percent (30 to 60%) carbon monoxide (CO), twenty-five percentTo thirty percent (25% to 30%) hydrogen gas (H)₂) Zero to five percent (0 to 5%) methane (CH)₄) Five to fifteen percent (5 to 15%) carbon dioxide (CO)₂) Plus a lesser or greater amount of water vapor, a lesser amount of sulfur compounds, hydrogen sulfide (H)₂S), carbonyl sulfide (COS), ammonia (NH)₃) And other trace contaminants.

In particular embodiments, the presence of hydrogen results in an increase in the overall efficiency of alcohol production by the fermentation process.

The syngas composition can be modified to provide the desired or optimal H₂:CO:CO₂A ratio. The syngas composition can be improved by adjusting the feedstock fed to the gasification process. Desired H₂:CO:CO₂The ratio depends on the desired fermentation product of the fermentation process.

Operating a fermentation process in the presence of hydrogen has the effect of reducing the CO produced by the fermentation process₂An additional benefit of the amount of (c). E.g. containing a minimum of H₂Will generally produce ethanol and CO by the following stoichiometry₂：[6CO+3H₂O→C₂H₅OH+4CO₂]. As the amount of hydrogen utilized by the C1 immobilized bacteria increases, CO produced₂Reduced amount of [ e.g., 2CO +4H₂→C₂H₅OH+H₂O]。

When CO is the only carbon and energy source for ethanol production, a portion of the carbon is lost to CO as follows₂：

6CO+3H₂O→C₂H₅OH+4CO₂(Δ G ° -224.90 kJ/mol ethanol)

With available H in the substrate₂Is increased, CO is produced₂The amount of (c) is reduced. At a stoichiometric ratio of 2:1 (H)₂CO) is completely avoided₂Is generated.

5CO+1H₂+2H₂O→1C₂H₅OH+3CO₂(Δ G ° -204.80 kJ/mol ethanol)

4CO+2H₂+1H₂O→1C₂H₅OH+2CO₂(Δ G ° -184.70 kJ/mol ethanol)

3CO+3H₂→1C₂H₅OH+1CO₂(Δ G ° -164.60 kJ/mol ethanol)

"stream" refers to any substrate that can be transferred, 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, "reactant" refers to a substance that participates in and undergoes a change during a chemical reaction. In particular embodiments, the reactants include, but are not limited to, CO and/or H₂。

As used herein, "microbe-inhibiting agent" refers to one or more ingredients that slow or prevent a particular chemical reaction or another process involving a microbe. In particular embodiments, microbial inhibitors include, but are not limited to, oxygen (O)₂) Hydrogen Cyanide (HCN), acetylene (C)₂H₂) And BTEX (benzene, toluene, ethylbenzene, xylene).

As used herein, "catalyst inhibitor," "sorbent inhibitor," and the like refer to one or more substances that reduce the rate of or prevent a chemical reaction. In particular embodiments, the catalyst inhibitor and/or sorbent inhibitor may include, but is not limited to, hydrogen sulfide (H)₂S) and carbonyl sulfide (COS).

"removal process," "removal module," "purge module," and the like include techniques capable of converting and/or removing microbial inhibitors and/or catalyst inhibitors from a gas stream. In particular embodiments, the catalyst inhibitor must be removed by the upstream removal module in order to prevent inhibition of the one or more catalysts in the downstream removal module.

The terms "ingredient," "contaminant," and the like as used herein refer to a microbial inhibitor and/or a catalyst inhibitor that may be found in a gas stream. In particular embodiments, these ingredients include, but are not limited to, sulfur compounds, aromatics, alkynes, alkenes, alkanes, alkenes, nitrogen compounds, phosphorous compounds, particulates, solids, oxygen, halogenated compounds, silicon-containing compounds, carbonyl compounds, metals, alcohols, esters, ketones, peroxides, aldehydes, ethers, and tars.

The terms "treated gas," "treated stream," and the like refer to a gas stream that has passed through at least one removal module and has had one or more components removed and/or converted.

The term "carbon capture" as used herein refers to sequestration from the inclusion of CO₂And/or carbon compounds of a stream of CO (including CO)₂And/or CO), and:

introducing CO₂And/or CO to product; or

Introducing CO₂And/or CO conversion to a substance suitable for long term storage; or

Introducing CO₂And/or CO is captured in a substance suitable for long-term storage;

or a combination of these processes.

The terms "bioreactor", "reactor", and the like include a fermentation device consisting of one or more vessels and/or a tower or piping arrangement, including a Continuously Stirred Tank Reactor (CSTR), an Immobilized Cell Reactor (ICR), a Trickle Bed Reactor (TBR), a bubble column, an airlift fermentor, a static mixer, a circulating loop reactor, a membrane reactor such as a hollow fiber membrane bioreactor (HFM BR)), a bubble reactor, a small bubble reactor, a micro bubble reactor, or other vessel or other device suitable for gas-liquid contact. The reactor is preferably adapted to receive a gaseous substrate, comprising CO or CO₂Or H₂Or mixtures thereof. The reactor may comprise a plurality of reactors (trays) in parallel or in series. For example, the reactors may include a first growth reactor in which the bacteria are cultured and a second fermentation reactor into which fermentation broth from the growth reactor may be fed and in which most of the fermentation product may be produced.

"nutrient medium" is used to describe a bacterial growth medium. Preferably, the fermentation process utilizes a nutrient medium within the bioreactor. Generally, the 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 utilized in the metabolic pathway of a microorganism. Exemplary nutrients include potassium, vitamin B, trace metals, and amino acids.

The term "fermentation broth" or broth "is intended to encompass a mixture of components including a nutrient medium and a culture or one or more microorganisms. Preferably, the fermentation process utilizes a fermentation broth to ferment the syngas stream into one or more products.

The term "acid" as used herein includes both carboxylic acids and associated carboxylate anions, such as a mixture of free acetic acid and acetate present in a fermentation broth as described herein. The ratio of molecular acid to carboxylate in the fermentation broth depends on the pH of the system. In addition, the term "acetate salt" includes acetate salts alone as well as acetic acid molecules or mixtures of free acetic acid and acetate salts, such as mixtures of acetate salts and free acetic acid present in a fermentation broth as described herein.

The term "desired composition" is used to refer to the desired level and type of components in a substance, such as a gas stream, including but not limited to syngas. More particularly if the gas contains specific components (e.g. CO, H)₂And/or CO₂) And/or contains a specific component in a specific ratio and/or does not contain a specific component (e.g., a contaminant harmful to microorganisms) and/or does not contain a specific component in a specific ratio, the gas is considered to have a "desired composition". More than one component may be considered in determining whether the gas stream has the desired composition.

Unless the context requires otherwise, the phrases "fermentation", "fermentation process" or "fermentation reaction" and the like as used herein are intended to encompass both the growth phase and the product biosynthesis phase of the gaseous substrate.

"microorganisms" are microscopic organisms, in particular bacteria, archaea, viruses or fungi. The microorganism of the present invention is typically a bacterium. As used herein, a recitation of "microorganism" should be considered to encompass "bacteria". It should be noted that the terms "microorganism" and "bacterium" are used interchangeably throughout this document.

A "parent microorganism" is a microorganism used to produce the microorganism of the invention. A parent microorganism can be a naturally occurring microorganism (e.g., a wild-type microorganism) or a microorganism that has been previously modified (e.g., a mutant microorganism or a recombinant microorganism). The microorganism of the invention may be modified to express or overexpress one or more enzymes that are not expressed or are overexpressed in the parent microorganism. Similarly, a microorganism of the invention can be modified to contain one or more genes that are not contained in the parental microorganism. The microorganism of the invention may also be modified to not express or express lower amounts of one or more enzymes expressed in the parent microorganism. In one embodiment, the parent microorganism is Clostridium autoethanogenum, Clostridium autodahlii (Clostridium ljungdahlii) or Clostridium ragsdalei (Clostridium ragsdalei). In a preferred embodiment, the parental microorganism is Clostridium autoethanogenum LZ1561, deposited at 7.2010 on 7.6.6.according to the clause of the Budapest Treaty at 7.2010 on 7.6.6.7.deutsche Sautsche Sammlung von Mikroorganismen und Zellkulturen GmbH (DSMZ) in Braunschweig Inhoffenstra beta.e 7B, D-38124, Germany, and has the accession number DSM 23693. This strain is described in international patent application No. PCT/NZ2011/000144, which is published as WO 2012/015317.

The term "derived from" means that the nucleic acid, protein or microorganism is modified or engineered from a different (e.g., parental or wild-type) nucleic acid, protein or microorganism in order to produce a new nucleic acid, protein or microorganism. Such modifications or alterations typically include insertions, deletions, mutations or substitutions of nucleic acids or genes. Generally, the microorganism of the invention is derived from a parental microorganism. In one embodiment, the microorganism of the invention is derived from clostridium autoethanogenum, clostridium andraeanum, or clostridium ragsdalei. In a preferred embodiment, the microorganism of the invention is derived from Clostridium autoethanogenum LZ1561 deposited under DSMZ accession number DSM 23693.

"Wood-Ljungdahl" refers to the carbon-immobilized Wood-Yangdahl pathway as described, for example, by Ragsdale, Biochim Biophys Acta,1784: 1873-. Predictably, "wood-Yandaer microorganisms "are microorganisms which contain the wood-Yandaer pathway. Generally, the microorganisms of the present invention contain a natural wood-Yandael pathway. In this context, the wood-Yandall pathway may be a natural unmodified wood-Yandall pathway, or may be a wood-Yandall pathway that has been genetically modified to some extent (e.g., overexpressed, heterologously expressed, knocked-out, etc.), provided that it still converts CO, CO₂And/or H₂Conversion to acetyl-CoA.

"C1" refers to a carbon molecule, e.g., CO₂、CH₄Or CH₃And (5) OH. "C1 oxygenate" means a carbon molecule further comprising at least one oxygen atom, e.g., CO₂Or CH₃And (5) OH. "C1 carbon source" refers to a carbon molecule that is used as part or the sole carbon source for the microorganisms of the present invention. For example, the C1 carbon source may include one or more of the following: CO, CO₂、CH₄、CH₃OH or CH₂O₂. Preferably, the C1 carbon source includes CO and CO₂One or both of them. A "C1 immobilized microorganism" is a microorganism having the ability to produce one or more products from a C1 carbon source. Generally, the microorganism of the present invention is a C1-immobilized bacterium.

An "anaerobic microorganism" is a microorganism that does not require oxygen to grow. Anaerobic microorganisms may produce adverse reactions or even die if oxygen is present above a certain threshold. However, some anaerobic microorganisms are able to tolerate low levels of oxygen (e.g., 0.000001% to 5% oxygen). Typically, the microorganism of the invention is an anaerobic microorganism.

"acetogens" are obligate anaerobic bacteria that utilize the wood-Yangdale pathway as their primary mechanism for energy conservation and synthesis of acetyl-CoA and acetyl-CoA derived products, such as acetate (Ragsdale, Biochim Biophys Acta,1784: 1873-. In particular, acetogens use the wood-yandall pathway as: (1) for removing CO from₂A mechanism for reductive synthesis of acetyl-coa; (2) a terminal electron receiving and energy saving process; (3) for the immobilisation (assimilation) of CO in cellular carbon Synthesis₂The mechanism of (Drake, academic Prokaryotes, described in The Prokaryotes, 3 rd edition, page 354, New York, NY, 2006). All naturally occurring acetogens are C1 immortal, anaerobic, autotrophic and nonmethanotrophic. Typically, the microorganism of the invention is an acetogen.

An "ethanologen" is a microorganism that produces or is capable of producing ethanol. Typically, the microorganism of the invention is an ethanologenic organism.

An "autotroph" is a microorganism that is capable of growing in the absence of organic carbon. In contrast, autotrophs use inorganic carbon sources, such as CO and/or CO₂. Typically, the microorganism of the invention is an autotroph.

"carboxydotrophic organisms" are microorganisms that are capable of utilizing CO as the sole source of carbon and energy. Typically, the microorganism of the invention is a carboxydotrophic organism.

"methanotrophic organisms" are microorganisms that are capable of utilizing methane as the sole source of carbon and energy. In certain embodiments, the microorganism of the invention is a methanotrophic organism or is derived from a methanotrophic organism. In other embodiments, the microorganism of the invention is not a methanotrophic organism or is not derived from a methanotrophic organism.

"substrate" refers to a source of carbon and/or energy of the microorganism of the invention. Typically, the substrate is gaseous and comprises a C1 carbon source, e.g., CO₂And/or CH₄. Preferably, the substrate comprises the C1 carbon source CO or CO + CO₂. The substrate may also contain other non-carbon components, such as H₂Or N₂。

The term "co-substrate" refers to a substance that, while not necessarily the primary source of energy and material for product synthesis, can be used for product synthesis when added to another substrate (such as a primary substrate).

The composition of the substrate may have a significant impact on the efficiency and/or cost of the reaction. For example, oxygen (O) is present₂) The efficiency of the anaerobic fermentation process may be reduced. Depending on the composition of the substrate, it may be desirable to treat, scrub or filter the substrate to remove any undesirable impurities (such as toxins, undesirable components or dust particles) and/or to addThe concentration of the desired component is added.

In certain embodiments, the fermentation is conducted in the absence of a carbohydrate substrate (such as a sugar, starch, lignin, cellulose, or hemicellulose).

The microorganisms of the present invention may be cultured with a gas stream to produce one or more products. For example, the microorganisms of the invention may produce or may be 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)), (WO 35a), Fatty acids (WO 2013/191567), 2-butanol (WO 2013/185123), 1, 2-propanediol (WO 2014/036152), 1-propanol (WO 2014/0369152), branched acid derivative products (WO 2016/191625), 3-hydroxybutyrate (WO 2017/066498) and 1, 3-butanediol (WO 2017/0066498). In certain embodiments, the microbial biomass itself may be considered a product. These products may be further converted to produce at least one component of diesel, jet fuel, and/or gasoline. In addition, the microbial biomass may be further processed to produce Single Cell Proteins (SCPs).

"Single Cell Protein (SCP)" refers to a microbial biomass that can be used in protein-rich human and/or animal feed foods, often replacing conventional sources of protein supplementation, such as soybean meal or fish meal. The process may include additional separation steps, processing steps or processing steps in order to produce single cell proteins or other products. For example, the method can include sterilizing the microbial biomass, centrifuging the microbial biomass, and/or drying the microbial biomass. In certain embodiments, the microbial biomass is dried using spray drying or paddle drying. The method may further comprise reducing the nucleic acid content of the microbial biomass using any method known in the art, as ingestion of a diet high in nucleic acid content may result in accumulation of nucleic acid degradation products and/or gastrointestinal discomfort. The single-cell protein may be suitable for feeding animals, such as livestock or pets. In particular, the animal feeding diet may be suitable for feeding one or more of beef cattle, dairy cows, pigs, sheep, goats, horses, mules, donkeys, deer, buffalo/bison, llama, alpaca, reindeer, camels, ruminants, gayal, yaks, chickens, turkeys, ducks, geese, quail, guinea fowl, squab/pigeon, fish, shrimp, crustaceans, cats, dogs and rodents. The composition of the food fed to the animal can be tailored to the nutritional requirements of different animals. Additionally, the process can include blending or combining the microbial biomass with one or more excipients.

"excipient" can refer to any substance that can be added to microbial biomass to enhance or modify the form, nature, or nutritional content of the food fed to an animal. For example, the excipients may include one or more of the following: carbohydrates, fibres, fats, proteins, vitamins, minerals, water, flavourings, sweeteners, antioxidants, enzymes, preservatives, probiotics or antibiotics. In some embodiments, the excipient may be hay, straw, silage, grain, oil or fat, or other plant material. The excipients may be those described in Chiba, section 18: diet Formulation and Common Feed Ingredients, Animal Nutrition Handbook, revised 3 rd edition, pages 575 to 633, 2014 any of the fed food Ingredients identified.

A "natural product" is a product produced by a microorganism that has not been genetically modified. For example, ethanol, acetate and 2, 3-butanediol are natural products of Clostridium autoethanogenum, Clostridium andreanum and Clostridium ragsdalei. A "non-natural product" is a product produced by a genetically modified microorganism, and not a product produced by a genetically unmodified microorganism from which the genetically modified microorganism is derived.

"selectivity" refers to the ratio of the yield of a product of interest to the yield of the total fermentation product produced by a microorganism. The microorganisms of the present invention may be engineered to produce products with a particular selectivity or with the lowest selectivity. In one embodiment, the target product comprises at least about 5%, 10%, 15%, 20%, 30%, 50% or 75% of the total fermentation product produced by the microorganism of the invention. In one embodiment, the target product comprises at least 10% of the total fermentation product produced by the microorganism of the invention, such that the microorganism of the invention has a selectivity for the target product of at least 10%. In another embodiment, the target product comprises at least 30% of the total fermentation product produced by the microorganism of the invention, such that the microorganism of the invention has a selectivity for the target product of at least 30%.

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

The cultivation/fermentation should ideally be carried out under suitable conditions to produce the desired product. Typically, the culturing/fermentation is performed 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 (if a continuously stirred tank reactor is used), inoculum level, maximum gas substrate concentration to ensure that the gas in the liquid phase does not become limiting, and maximum product concentration 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 limiting, since incubation under gas limiting conditions may consume product.

Operating the bioreactor at elevated pressure allows for increasing the rate of gas mass transfer from the gas phase to the liquid phase. Therefore, it is generally preferred that the cultivation/fermentation is carried out at a pressure higher than atmospheric pressure. In addition, since a given gas conversion is somewhat a function of substrate retention time and retention time is indicative of the required volume of the bioreactor, the use of a pressurized system can greatly reduce the volume of the required bioreactor and thus reduce the capital cost of the culture/fermentation equipment. This in turn means that the retention time, which is defined as the volume of liquid in the bioreactor divided by the input gas flow rate, can be shortened when the bioreactor is maintained at an elevated pressure rather than atmospheric pressure. The optimal reaction conditions will depend in part on the particular microorganism used. In general, however, it is preferred to carry out the fermentation at a pressure above atmospheric pressure. In addition, since a given gas conversion is somewhat a function of substrate retention time, and achieving a desired retention time in turn is indicative of the required volume of the bioreactor, the use of a pressurized system can greatly reduce the volume of the required bioreactor, and thus reduce the capital cost of the fermentation equipment.

The desired product can be isolated or purified from the fermentation broth using any suitable removal process, which can utilize methods or combinations of methods known in the art, including, for example, fractional distillation, vacuum distillation, evaporation, pervaporation, gas stripping, phase separation, and extractive fermentation (including, for example, liquid-liquid extraction). In certain embodiments, the target product is recovered from the fermentation broth by: continuously removing a portion of the fermentation broth from the bioreactor, separating the microbial cells from the fermentation broth, preferably by filtration, and recovering one or more target products from the fermentation broth. The alcohol and/or acetone may be recovered, for example, by distillation. The acid may be recovered, for example, by adsorption on activated carbon. The separated microbial cells may be returned to the bioreactor. The cell-free permeate remaining after the target product has been removed may also be returned to the bioreactor. Additional nutrients (such as vitamin B) may be added to the cell-free permeate to supplement the culture medium, which is then returned to the bioreactor.

By "enriched" is meant a stream having an increased amount of a component compared to the stream prior to the enrichment step.

Description of the invention

The present disclosure shows that by integrating gasification and fermentation operations into an integrated system, unexpected synergy results in improved overall efficiency of the integrated system. More specifically, the present disclosure identifies such integration: wherein a syngas from a gasification process is treated with an adsorbent to remove at least one tar, such as hydrocarbons or oxygenates, and the adsorbent is regenerated using a tail gas of a fermentation operation, thereby becoming enriched in tar and increased in heating value. The enriched tail gas may be combusted in a steam generation unit to generate steam that may be used for many different purposes. One such use that provides further integration is the use of steam to generate power that then drives the compressor of the gas fermentation process.

The synthesis gas produced from gasification of biomass or waste feedstocks contains hydrocarbons and oxygenates (commonly referred to as tars) in quantities and concentrations related to the temperature of the feedstock and the gasification process. Generally, in gasifiers using air as the oxidant, the temperature is lower than in processes using oxygen-enriched air or pure oxygen as the oxidant. The syngas produced by the low temperature gasifier produces high concentrations of tars, such as 1000ppmv to 10,000ppmv, and also methane, at concentrations of 1% to 5% by volume. Tars and methane are undesirable products of gas fermentation. Neither is fermentable, in particular tar, which should be removed for the operation of the gas fermentation process.

Heavier, higher boiling tars can be removed by cooling the syngas, which operation condenses these tars along with the water present in the syngas. Such liquid products (i.e., condensates) comprise one or more of hydrocarbons, oxygenates, and/or water and are waste products that typically require disposal. In some embodiments where a large amount of condensate is produced and the individual components of the condensate have significantly greater concentrations, it may be desirable and economical to purify the components for sale. In another embodiment, the disposal technique for the condensate is combustion. The condensate may be combusted by using a flame produced by combustion of fuel gas, natural gas, syngas or fermentation tail gas obtained from a gas fermentation process. Alternatively, the condensate may be passed to a wastewater treatment process for disposal, which results in increased yield compared to combustion condensate. Using fermentation off-gas (which may contain methane and residual CO and H)₂) Is desirable because the tail gas is low cost and is also typically a waste stream that may require disposal. Further uniquely adapted by using fermentation off-gasIn this integration, the value of the tail gas as a combustible stream is increased because any methane content of the syngas can pass into the tail gas and act to increase the heating value of the tail gas.

In other embodiments, such as in a low temperature gasification embodiment, a large amount of condensate and methane are present in the syngas at the same time, and the resulting tail gas is of significant value for combustion. However, some gasification processes, such as high temperature gasification processes, may result in syngas containing very little tar or methane, e.g., < 0.5% in one embodiment, or as low as 0.1 mole% in another embodiment, and result in fermentation tail gas that may be too lean to burn. In this embodiment, little or no condensate needs to be disposed of. The tar and the oxygen-containing compounds are desorbed by using the fermentation tail gas flow, so that the energy density of the fermentation tail gas is enriched, and the opportunity of using the originally low-value tail gas in a higher-value generation environment is provided. For example, instead of adding methane to combust the tail gas, the enriched tail gas may be used by a steam boiler or even a power generation unit (such as a cogeneration unit or a direct generation unit) after desorption of tars and oxygenates. The enriched fermentation tail gas has increased energy value, and combustion efficiency is improved when used in a steam boiler or a power generation unit, etc. Higher efficiencies are achieved because nitrogen may need to be obtained and used to desorb and regenerate the adsorbent without using the tail gas to desorb hydrocarbons and oxygenates from the adsorbent. The use of internal process streams reduces costs.

Lower boiling light tars, such as benzene, toluene, ethylbenzene and xylenes (BTEX), may also be present in the synthesis gas from the gasification process or in the industrial gas, which should be removed prior to gas fermentation. BTEX can be removed by an adsorption unit, such as a Temperature Swing Adsorption (TSA) unit or a Pressure Swing Adsorption (PSA) unit. A second use of the fermentation tail gas is to desorb BTEX from the adsorbent bed as a purge gas. After being used as a purge gas, the tail gas contains residual syngas Components (CH)₄、CO、H₂) And the desorbed BTEX is enriched, thereby forming an enriched tail gas containing a large amount of recoverable energy. In addition to the remaining fermentation tail gas, the enriched tail gas stream can be combusted in a steam boiler to produce steam, such as a high pressure stream, which is suitable for a variety of process units, including those used in gasification and gas fermentation systems.

There is a surprisingly large amount of residual energy in the enriched tail gas, and thus a surprising amount of steam is generated from the enriched tail gas. In one embodiment, a forced air gasification system can recover 75% of the chemical energy contained in a feedstock as syngas, where 20% (15% of the feedstock, 20% of 75%) can be present as BTEX, methane and other light hydrocarbons, and where 80% can be present as CO and H₂Are present. For 1 dry ton of food fed with 18 gj coke/ton lower calorific value, this means that 3 gj coke will be present as non-fermentable material, corresponding to a steam production of about 1.2 tons. The enriched tail gas is enriched in N compared to the synthesis gas stream or the process off-gas from the gasification process₂(ii) a Is rich in CO₂(ii) a Impurity depletion; or any combination thereof, resulting in an enriched tail gas that provides an unexpected improvement in desorption of adsorbed components. The steam generated can be used to: distillation of fermentation products, operation of adsorption coolers, steam driven compression, evaporation of waste water, drying of biocatalysts, in-situ Steam (SIP) operations, Cleaning In Place (CIP) operations, drying of raw materials, steam driven raw material conveyors, heating of buildings and power generation. An additional level of integration can be achieved when the steam produced is used to generate power and the power is used to drive a compressor of the gas fermentation process.

Other embodiments include one or more effluents selected from the group consisting of: biogas generated by a wastewater treatment process, tail gas generated by a fermentation process, unused syngas generated by a gasification process, microbial biomass generated by a fermentation process, microbial biomass generated by a wastewater treatment process, raw ethanol from a product recovery process, fusel oil from a product recovery process, water depleted of microbial biomass, wastewater generated by a fermentation process, and clarified water from a wastewater treatment process, which effluents may be sent to a gasification process to produce a syngas stream, used by a gasification process as a heating source, and/or used by a gasification process to quench a syngas stream. The synthesis gas stream is preferably suitable for gas fermentation.

These various effluents are produced during or downstream of the fermentation process. The wastewater stream produced by the fermentation process contains organic metabolites such as microbial biomass, ethanol, acetate, and 2, 3-butanediol, as well as various inorganic compounds such as salts and trace metals. The wastewater stream is typically sent to a wastewater treatment process. A typical wastewater treatment process comprises the following steps: (i) isolating microbial biomass, which is a suspended solid; (ii) concentrating microbial biomass solids in a single long residence time (about thirty days) anaerobic digester; (iii) the clarified effluent containing soluble organics is concentrated in a short residence time (approximately two to three days) anaerobic digester where the amount of microbial biomass solids is reduced. Typically, these anaerobic digesters consume a majority, preferably greater than eighty percent (80%), of the organic matter in the feed and produce biogas products. Biogas products are composed primarily of methane (CH)₄) And carbon dioxide (CO)₂) And (4) forming.

The biogas product may be useful for generating power. However, in order to use the biogas for power generation, the biogas must typically be processed by one or more removal modules. Furthermore, as explained later, it was found that the use of microbial biomass to produce biogas is a relatively low value use of microbial biomass when compared to the opportunity to gasify or dry the microbial biomass.

In addition to the aforementioned steps, the wastewater treatment process may include additional treatment steps after the anaerobic digester. Typically, the treated effluent from the anaerobic digester is subjected to additional treatments including aerobic treatment, struvite recovery, nitrogen recovery, and in some cases reverse osmosis. Clarified water produced by the wastewater treatment process is suitable for reuse and/or discharge. One suitable way of using such clarified water is to recycle the clarified water to the fermentation process and/or the gasification process.

Although wastewater treatment processes can successfully treat wastewater from fermentation processes to produce clarified water, organic metabolites in wastewater streams often present some challenges. In particular, treatment of microbial biomass in wastewater streams by wastewater treatment processes can present design challenges due to: (i) high protein content, thus generating large amounts of ammonia during anaerobic digestion, and (ii) requiring large bulk space to accommodate wastewater treatment processes.

Ammonia presents a challenge to anaerobic digestion because if the concentration of ammonia is high, ammonia is associated with inhibiting methanogenesis during the anaerobic digestion process. Inhibitory concentrations of ammonia have been found to be in the range of 2g/L to 3 g/L. This threshold may be greatly exceeded because digestion of the isolated microbial biomass may result in an ammonia concentration greater than 20 g/L. Therefore, in order to process microbial biomass by a wastewater treatment process, an ammonia stripping process is typically required to reduce the ammonia concentration below inhibitory levels.

The requirement for large plot space poses a significant problem in areas where land is scarce. Each component of the wastewater treatment process requires a large amount of space because of the large volume to be treated. For example, in some cases, a long residence time anaerobic digester may exceed 7,000m³。

The inventors have discovered that these challenges can be overcome by recycling at least a portion of the microbial biomass to the gasification process. As less microbial biomass is sent to anaerobic digestion, less ammonia is produced, thus reducing and/or eliminating the need for an ammonia stripping process. Furthermore, since a larger volume of effluent from the fermentation process is sent to the gasification process, a smaller volume of effluent is sent to the wastewater treatment process. Because of the smaller volume of effluent treated by the wastewater treatment process, the required volume and corresponding plot space requirements are reduced, making this design advantageous for areas where land is scarce.

In addition to overcoming the aforementioned challenges, recycling microbial biomass to the gasification process also provides the following advantageous results: (i) a large portion of the energy contained in the biomass is recovered; (ii) h in the resulting syngas stream₂Increased CO ratioLarge; (iii) the inorganic content, metallic compounds and alkali elements in the microbial biomass (which would normally require additional treatment steps of a wastewater treatment process) are conveniently collected in the gasification process as part of the ash that already needs to be disposed of, thus reducing overall waste disposal; and (iv) nitrogen contained in the biomass will react in the gasifier to N₂、NH₃And trace amounts of HCN, which is well integrated with existing removal processes.

The inventors have also surprisingly found that the yield in recycling biomass to gasification is increased when compared to using biomass in the production of biogas. In particular, the inventors have found that the gain is increased by 321% when comparing the utilization of biomass in syngas with the utilization of biomass in the production of biogas.

This percentage gain increase is best shown in the table below. The table shows the values generated from 20GJ/h of biomass by each route.

Watch (A)

The calculations shown in the table above compare the conversion value of biomass to biogas via anaerobic digestion with the conversion value of biomass to syngas via gasification. The conversion efficiency for biogas production from biomass via anaerobic digestion is about sixty percent (60%). The conversion efficiency of syngas production from biomass via gasification is about seventy-five percent (75%), which may vary depending on the gasification technology used. GJ/h product gas represents GJ/h biomass multiplied by the corresponding conversion efficiency. GJ/h ethanol represents GJ/h product gas times the conversion efficiency of the gas fermentation. The conversion efficiency of gas fermentation for ethanol production is conservatively about fifty-five percent (55%). With this conversion efficiency, GJ/h ethanol was found to be 8.25. By 11 months and 5 days 2018, the current price of biogas without renewable incentives is between U.S. dollars ($4) and the european union $ ten ($ 10). For analytical purposes, a biogas price of eight dollars per gigajoule ($8/GJ product value) was used. By 11/5 days 2018, the price of low carbon ethanol is currently $ 850/ton ethanol in the european union, $ 1100/ton ethanol in china, and $ 1200/ton ethanol in the united states. For analytical purposes, a price of 1000 dollars/ton of ethanol was used, corresponding to $ 37.30/GJ. The $/h yield is GJ/h product gas multiplied by $/GJ product value. The percentage gain is a comparison of the $/h gain for anaerobic digestion to biogas versus the $/h gain for gasification to syngas. The GJ biomass value illustrates the value of the biomass given the selected process. This is calculated by dividing $/h yield by GJ/h biomass. As shown, the use of biomass to produce syngas through gasification greatly increases the revenue and value of the biomass.

An additional benefit of feeding microbial biomass to the gasification process is that the microbial biomass can help provide a supplemental amount of syngas, which may be needed to adequately supply the fermentation process. For example, based on current design parameters, a gasifier feed rate of about 1,200 dry tons per day, corresponding to 50 dry tons per hour, is required to supply the syngas required for a 100,000 ton/year ethanol production fermentation process. The biomass produced by fermentation processes of this scale is typically between 1,000kg/h and 1,200 kg/h. This amount of biomass is considerable. Where gasifier feedstock is limited or expensive, it may be particularly beneficial to generate make-up quantities of syngas by biomass gasification.

The biomass produced by the fermentation process may require an additional drying step before being passed to the gasifier in order to increase the percentage of biomass content. Depending on the requirements of the gasifier, it may be necessary to dry the biomass to an extent that the biomass constitutes more than 20% by weight.

However, gasifying biomass with increased moisture content has the effect of increasing the H in the syngas produced₂The additional benefit of the CO ratio. At a moisture content of about 15 wt% in the gasification feedstock, the resulting syngas stream has a H of 1:1₂The ratio of CO. When the moisture in the gasification feedstock increased to 40 wt.%, the resulting syngas stream had a H of 2:1₂The ratio of CO. As previously mentioned, H in the syngas stream fed to the fermentation process₂An increased CO ratio leads to an increased efficiency of the fermentation process.

The substrate and/or C1 carbon source may be an off-gas obtained as a by-product of an industrial process, or may be an off-gas from another source, such as automobile exhaust, biogas or landfill gas, or an off-gas from electrolysis. The substrate and/or C1 carbon source may be syngas generated by pyrolysis, torrefaction, or gasification. In other words, the waste material may be recycled by pyrolysis, torrefaction, or gasification to generate syngas for use as a substrate and/or a carbon source for C1. In certain embodiments, the industrial process is selected from: ferrous metal product manufacturing (such as steel mill manufacturing), non-ferrous metal product manufacturing, petroleum refining, power production, carbon black production, paper and pulp manufacturing, ammonia production, methanol production, coke manufacturing, or any combination thereof. In these embodiments, the substrate and/or C1 carbon source may be captured from the industrial process using any known method and then vented to the atmosphere. The substrate and/or C1 carbon source may be syngas, such as syngas obtained by: gasification of coal, gasification of refinery residues, gasification of biomass, gasification of lignocellulosic materials, black liquor gasification, gasification of municipal solid waste, gasification of industrial solid waste, gasification of sewage, gasification of sludge from wastewater treatment, reforming of natural gas, reforming of biogas, reforming of landfill gas, or any combination thereof. Examples of municipal solid waste include tires, plastics, and fibers in shoes, clothing, textiles. Municipal solid waste may be classified or unclassified. Examples of biomass may include lignocellulosic materials, and may also include microbial biomass. Lignocellulosic materials may include agricultural and forest waste.

The figures discussed below relate first to processes and plants that include gasification, and then to processes and plants in which gasification is not required to produce syngas. In all cases, the off-gas produced by the fermentation is used to desorb at least one component from the adsorbent, thereby enriching the off-gas. The enriched tail gas has a number of possible uses. The off-gas from the fermentation also surprisingly behaves as a better desorbent than, for example, untreated syngas.

Fig. 1 shows a process integration scheme according to one embodiment of the invention, depicting the integration of a gasification process 300 (with a gas fermentation process 100), a product recovery process 400, and a wastewater treatment process 200. These processes are integrated in a manner that provides surprising synergy and advantages. The gasification process 300 receives a gasification feed 301, which may be any suitable material that can be gasified to produce a syngas stream 302. In each case, the gasification feed 301 is at least partially composed of sorted and/or unsorted municipal solid waste. In other cases, the gasification feed 301 is at least partially composed of forest waste and/or agricultural waste. In particular embodiments, the gasification feed 301 consists of a combination of two or more of the following: sorted municipal solid waste, unsorted municipal solid waste, forest waste, agricultural waste, at least one effluent from the fermentation process 100, at least one effluent from the product recovery process 400, and at least one effluent from the wastewater treatment process 200.

The gasification process 300 receives a gasification feed 301 and produces a syngas stream 302 suitable for fermentation by the gas fermentation process 100. The fermentation process 100 utilizes this stream as a carbon source to produce one or more products, which may be at least partially contained in one or more effluent streams 102, 104. In each case, the effluent from fermentation process 100 is a fermentation broth. However, certain components of the syngas will be removed in the adsorption unit 10 before the syngas is fermented in the fermentation process 300. The removed components include at least one of hydrocarbons, oxygenates, sulfur compounds, and/or nitrogen compounds. The component is adsorbed onto the adsorbent of the adsorption unit. The adsorption unit may be a temperature swing adsorption system, a pressure swing adsorption system, a swing bed system, a moving bed system, or a fixed bed system. Over time, the adsorbent may reach capacity and need to be regenerated. The desorbent and/or purge gas helps regenerate the adsorbent. As mentioned above, a further integration of the gasification process and the gas fermentation process is to use at least a portion of the tail gas 104 of the fermentation process 100 as a desorbent or purge gas 12 for the adsorption unit 10. The tail gas used as the desorbent or purge gas 12 for the adsorption unit 10 becomes enriched in components desorbed from the adsorbent, including at least one hydrocarbon, oxygenate, sulfur compound, and/or nitrogen compound, thereby forming an enriched tail gas 18 having a higher heating value than the stream 12. In this embodiment, the enriched tail gas 18 is directed to the steam boiler 14 to generate high pressure steam 20. The high pressure steam 20 is provided to the system 16, which generates power from the high pressure steam and drives a compressor that compresses the syngas prior to introducing the syngas into the gas fermentation process 100.

One or more products produced by the fermentation process 100 are removed and/or separated from the fermentation broth by a product recovery process 400. Preferably, the product recovery process 400 removes one or more products 406 and produces at least one effluent 402, 404, 408 comprising a reduced amount of the at least one product. The effluent may be sent to the wastewater treatment process 200 via conduit 402 to produce at least one effluent 202, which may be recycled to the gasification process 300 and/or the fermentation process 100.

The effluent from the fermentation process 100 is the off-gas produced by the fermentation process 100. At least a portion of the tail gas may be sent to the gasification process 300 via conduits 104, 124, and 125. A portion of the tail gas is directed in line 12 for use as desorbent and/or purge gas for adsorption unit 10. In an optional embodiment, at least a portion of the tail gas may be sent to the gasification process 300 via conduit 124 for use as part of the gasification feed 301. In another optional embodiment, at least a portion of the tail gas may be sent to gasification process 300 via conduit 114 to quench syngas stream 302.

In at least one embodiment, the effluent from fermentation process 100 is a fermentation broth. At least a portion of the fermentation broth is sent to product recovery process 400 via conduit 102. In at least one embodiment, the product recovery process 400 separates at least a portion of the microbial biomass from the fermentation process 100. In various embodiments, at least a portion of the microbial biomass separated from the fermentation broth is recycled to the fermentation process 100 via conduit 404. In various embodiments, at least a portion of the microbial biomass separated from the fermentation broth is sent to gasification process 300 via conduit 428. At least a portion of the microbial biomass may be used as part of the gasification feed 301.

In various optional embodiments, at least a portion of the wastewater stream from the fermentation process 100 comprising fermentation broth (which may contain microbial biomass) may be sent directly to the gasification process 300 via conduit 104 without being passed to the product recovery process 400. At least a portion of the wastewater may be sent to the gasification process 300 via conduit 124 for use as part of the gasification feed 301. At least a portion of the fermentation broth may be sent to gasification process 300 via conduit 114 to quench syngas stream 302.

In the case of processing the fermentation broth by the product recovery process 400, at least a portion of the microbial biomass-depleted water produced by removing the microbial biomass from the fermentation broth may be returned to the fermentation process 100 via a conduit 404 and/or sent to the gasification process 300 via a conduit 408. At least a portion of the microbial biomass-depleted water may be sent to the gasification process 300 via conduit 428 for use as part of the gasification feed 301. At least a portion of the microbial biomass-depleted water can be sent via line 418 to quench the syngas stream 302. Further, at least a portion of the effluent from the product recovery process 400 can be sent to the wastewater treatment process 200 via conduit 402. Preferably, the effluent from the product recovery process 400 contains a reduced amount of product and/or microbial biomass.

Preferably, the wastewater treatment process 200 receives and processes effluent from one or more processes to produce clarified water. The clarified water may be sent to one or more processes via conduit 202. In some cases, at least a portion of the clarified water is sent to the fermentation process via conduit 212. At least a portion of the clarified water may be sent to the gasification process 300 through a conduit 232 for use as part of the gasification feed 301. At least a portion of the clarified water may be sent to gasification process 300 via conduit 222 to quench syngas stream 302.

In some cases, wastewater treatment process 200 generates microbial biomass as part of the treatment process. At least a portion of the microbial biomass may be sent to the gasification process 300 via conduit 232. Preferably, the gasification process 300 utilizes at least a portion of the microbial biomass generated by the wastewater treatment process 200 as part of the gasification feed 301.

The wastewater treatment process 200 produces biogas as a byproduct of the treatment of microbial biomass. At least a portion of the biogas may be sent to the gasification process 300 via conduit 202. In some cases, at least a portion of the biogas is sent to the gasification process 300 via conduit 232 for use as part of the gasification feed 301. At least a portion of the biogas may be sent to gasification process 300 via conduit 222 to quench syngas stream 302.

Preferably, the gasification process 300 receives one or more effluents from the fermentation process 100, the product recovery process 400, and/or the wastewater treatment process 200, and produces a syngas stream 302. The syngas stream 302 is preferably suitable for use as a feedstock to the gas fermentation process 100.

To be suitable as feedstock for the gas fermentation process 100, the syngas stream 302 should preferably have a desired composition. In particular instances, the syngas 302 produced by the gasification process 300 contains one or more components that need to 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, alkenes, nitrogen compounds, phosphorous compounds, particulates, solids, oxygen, halogenated compounds, silicon-containing compounds, carbonyl compounds, metals, alcohols, esters, ketones, peroxides, aldehydes, ethers, and tars. These components may be removed by one or more removal processes.

Fig. 2 shows the process integration scheme from fig. 1, in addition to the adsorption unit 10, including a removal process 500 between the gasification process 300 and the gas fermentation process 100, according to an aspect of the invention.

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

When the removal process 500 is incorporated, at least a portion of the syngas 302 from 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 found in the syngas stream 302. Preferably, the removal process 500 leaves the components within allowable levels in order to produce a treated stream 502 suitable for fermentation by the fermentation process 100.

In various instances, the removal process 500 includes two or more removal modules selected from the group consisting of: the device comprises a hydrolysis module, an acid gas removal module, a deoxidation module, a catalytic hydrogenation module, a particle removal module, a chloride removal module and a hydrogen cyanide polishing module. In some cases, 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 (e.g., downstream fermentation process 100 and/or downstream removal modules within removal process 500).

One or more components removed and/or converted by removal process 500 can be introduced and/or concentrated by gasification of the microbial biomass. In some cases, the removal process 500 removes ammonia (NH)₃) And/or Hydrogen Cyanide (HCN). When the microbial biomass is gasified by the gasification process 300, the ammonia and/or hydrogen cyanide may be introduced and/or concentrated. Ammonia and hydrogen cyanide may be produced from the nitrogen contained in the microbial biomass that will react in the gasification process 300 to become N₂、NH₃And trace amounts of HCN.

Typically, the syngas stream fed to the fermentation process 100 is gaseous. However, the syngas stream may also be provided in alternative forms. For example, the syngas stream can be dissolved in a liquid saturated with syngas, which can then be fed into the fermentation process 100. By way of further example, the syngas may be adsorbed onto a solid support.

Preferably, the fermentation process 100 utilizes C1 immobilized microorganisms to ferment the syngas stream 302 and produce one or more products. The C1-immobilized microorganisms in fermentation process 100 are typically carboxydotrophic bacteria. In a specific embodiment, the carboxydotrophic bacterium is selected from the group comprising: moorella, clostridium, ruminococcus, acetobacter, eubacterium, butyrobacter, acetobacter, methanosarcina, and devulcanium. In various embodiments, the carboxydotrophic bacterium is clostridium autoethanogenum.

In some cases, one or more of the processes are integrated by utilizing at least a portion of at least one effluent from one process as a heating source for at least one other process.

Fig. 3 illustrates a process integration scheme according to an aspect of the present invention, which depicts the integration of a gasification process 300, a gas fermentation process 100, a product recovery process 400, and a wastewater treatment process 200. In various instances, at least one process is integrated by utilizing at least one effluent from the process as a heating source in at least one other process. In particular embodiments, biogas generated by wastewater treatment process 200 is used as a heating source for one or more processes. Preferably, at least a portion of the biogas generated by the wastewater treatment process 200 is used as a heating source for the gasification process 300. In some cases, the gasification process 300 utilizes at least a portion of the biogas generated by the wastewater treatment process 200 to melt at least a portion of the slag produced by the gasification process 300. In one or more embodiments, at least a portion of the biogas generated by the wastewater treatment process 200 is used as a heating source for the gas fermentation process 100. In one or more embodiments, at least a portion of the biogas generated by the wastewater treatment process 200 is used as a heating source for the product recovery process 400. In one or more embodiments, at least a portion of the biogas generated by the wastewater treatment process 200 is used as a heating source for the removal process 500.

In each case, the biogas stream from the wastewater treatment process 200 is sent to at least one removal process 600 via conduit 202 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 incorporated after the wastewater treatment process 200, at least a portion of the biogas from 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 found in the biogas stream. Preferably, the removal process 600 leaves the components within allowable levels in order to produce a treated stream 642, 612, 622, and/or 632 suitable for use by the subsequent one or more processes 400, 100, 500, and/or 300.

In particular embodiments, the off-gas generated by fermentation process 100 may also be used as a heating source for one or more processes. For example, at least a portion of the tail gas generated by the fermentation process 100 may be used as a heating source for the gasification process 300. In some cases, the gasification process 300 utilizes at least a portion of the tail gas generated by the fermentation process 100 to melt at least a portion of the slag produced by the gasification process 300. In one or more embodiments, at least a portion of the tail gas generated by the fermentation process 100 is used as a heating source for the product recovery process 400. In each case, off-gas from the fermentation process 100 is sent to at least one removal process before being sent to one or more processes.

In particular embodiments, unused syngas generated by the gasification process 300 is used as a heating source for one or more processes. Preferably, at least a portion of the unused syngas generated by the gasification process 300 is used as a heating source for the gasification process 300. In certain instances, the gasification process 300 utilizes at least a portion of the unused syngas generated by the gasification process 300 to melt at least a portion of the slag produced by the gasification process 300. In one or more embodiments, at least a portion of the unused syngas generated by the gasification process 300 is used as a heating source for the product recovery process 400. In each case, the unused syngas from the gasification process 300 is sent to at least one removal process before being sent to one or more processes.

The fermentation process 100 is preferably capable of producing a variety of products. These products can preferably be separated using the product recovery process 400. In various instances, at least a portion of at least one product produced by fermentation process 100 may be used as a source of one or more processes. In certain instances, at least a portion of the ethanol from the product recovery process 400 is used as a heating source for the gasification process 300. Preferably, the ethanol used as a heating source for one or more processes is caide ethanol that does not meet fuel-grade ethanol specification requirements. In certain instances, the gasification process 300 utilizes at least a portion of the caide ethanol from the product recovery process 400 to melt at least a portion of the slag produced by the gasification process 300.

In some cases, fermentation process 100 produces fusel oil. The fusel oil may be recovered by the product recovery process 400 by any suitable means. For example in the rectification column of a distillation apparatus. In at least one embodiment, at least a portion of the fusel oil from product recovery process 400 is used as a heating source for one or more processes. In some cases, at least a portion of the fusel oil from the product recovery process 400 is used as a heating source for the gasification process 300. Preferably, the gasification process 300 utilizes at least a portion of the fusel oil from the product recovery process 400 to melt at least a portion of the slag produced by the gasification process 300.

FIG. 4 illustrates one embodiment of using industrial waste gas as a substrate or C1 carbon source without gasification of the material to produce syngas. In each case, the feed 401 consists of an off-gas, which is an off-gas obtained as a by-product of an industrial process, or an off-gas from another source, such as automotive exhaust, biogas or landfill gas, or an off-gas from electrolysis. The industrial process is selected from: ferrous metal product manufacturing (such as steel mill manufacturing), non-ferrous metal product manufacturing, petroleum refining, power production, carbon black production, paper and pulp manufacturing, ammonia production, methanol production, coke manufacturing, or any combination thereof. Optionally, the feed 401 may also comprise at least one effluent from the fermentation process 100, at least one effluent from the product recovery process 400, and at least one effluent from the wastewater treatment process 200.

The fermentation process 100 utilizes the feed stream as a carbon source to produce one or more products, which may be at least partially contained in one or more effluent streams 102, 104. In each case, the effluent from fermentation process 100 is a fermentation broth. However, certain components of the treated feed will be removed in adsorption unit 10 before the feed is passed via line 22 and fermented in fermentation process 100. The removed components include at least one of hydrocarbons, oxygenates, sulfur compounds, and/or nitrogen compounds. Typical components that may be found in the feed 401 that may need to be removed by the adsorption unit include, but are not limited to, sulfur compounds, aromatics, alkynes, alkenes, alkanes, alkenes, nitrogen compounds, phosphorous compounds, particulates, solids, oxygen, halogenated compounds, silicon containing compounds, carbonyl compounds, metals, alcohols, esters, ketones, peroxides, aldehydes, ethers, and tars.

The components are adsorbed onto the adsorbent of the adsorption unit 10. The adsorption unit may be a temperature swing adsorption system, a pressure swing adsorption system, a swing bed system, a moving bed system, or a fixed bed system. Over time, the adsorbent may reach capacity and need to be regenerated. The desorbent and/or purge gas helps regenerate the adsorbent. At least a portion of the tail gas 104 of the fermentation process 100 may be used as the desorbent or purge gas 12 for the adsorption unit 10. The tail gas used as the desorbent or purge gas 12 for the adsorption unit 10 becomes enriched in components desorbed from the adsorbent, including at least one hydrocarbon, oxygenate, sulfur compound, and/or nitrogen compound, thereby forming an enriched tail gas 18 having a higher heating value than the tail gas desorbent 12. In this embodiment, the enriched tail gas 18 is directed to the steam boiler 14 to generate high pressure steam 20. The high pressure steam 20 is provided to the system 16 which generates power from the high pressure steam and drives a compressor which compresses the feed prior to introduction into the gas fermentation process 100 via line 22.

The effluent from the fermentation process 100 is the off-gas produced by the fermentation process 100. A portion of the tail gas is directed in lines 104 and 12 for use as desorbent and/or purge gas for adsorption unit 10. In an optional embodiment, at least a portion of the tail gas can be conveyed via line 124 to be combined with the feed 401.

As discussed above, one or more products produced by the fermentation process 100 are removed and/or separated from the fermentation broth by the product recovery process 400. Similarly, in at least one embodiment, as discussed above, the effluent from fermentation process 100 is a fermentation broth, and at least a portion of the fermentation broth is sent to product recovery process 400 via conduit 102.

FIG. 5 illustrates one embodiment of the generation of syngas using industrial waste gas as a substrate or C1 carbon source without gasification of the material, wherein the enriched tail gas in line 18 is directed to the power generation unit 48. Fig. 5 also shows an alternative embodiment in which the enriched tail gas in line 18 is directed via line 50 to a process recovery process and unit 400, for example to dry the product.

FIG. 6 illustrates an embodiment of the use of the gasifier 300 to generate syngas as a substrate or C1 carbon source, wherein the enriched tail gas in line 18 is directed to a power generation unit. Fig. 6 also shows an alternative embodiment in which the enriched tail gas is directed to a product recovery process and unit 400, for example to dry the product.

In the case of processing a fermentation broth by product recovery process 400, at least a portion of the microbial biomass-depleted water produced by removing the microbial biomass from the fermentation broth may be returned to fermentation process 100 via conduit 404 and/or transferred via conduit 408 for use as part of feed 401. Further, at least a portion of the effluent from the product recovery process 400 can be sent to the wastewater treatment process 200 via conduit 402. Preferably, the effluent from the product recovery process 400 contains a reduced amount of product and/or microbial biomass.

All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that prior art forms part of the common general knowledge in the field of endeavour in any country.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (e.g., meaning "including, but not limited to,") unless otherwise noted. The term "consisting essentially of … …" limits the scope of the composition, process or method to the specified materials or steps or to those materials or steps that do not materially affect the basic and novel characteristics of the composition, process or method. The use of alternatives (e.g., "or") should be understood to mean one, both, or any combination thereof of alternatives. As used herein, the term "about" means ± 20% of the indicated range, value, or structure, unless otherwise indicated.

Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. For example, unless otherwise specified, 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 stated range, and, where appropriate, to include fractions thereof (such as tenths and hundredths of integers).

All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Preferred embodiments of the present invention are described herein. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.