PROCESS FOR IMPROVING CARBON CONVERSION EFFICIENCY
20220333140 · 2022-10-20
Inventors
- Robert John Conrado (Washington, DC, US)
- Sean Dennis Simpson (Evanston, IL, US)
- Michael Emerson Martin (Chicago, IL, US)
- Jason Carl Bromley (Chicago, IL, US)
- Richard Russell Rosin (Glencoe, IL, US)
Cpc classification
C10K3/026
CHEMISTRY; METALLURGY
C12M43/00
CHEMISTRY; METALLURGY
B01J19/2465
PERFORMING OPERATIONS; TRANSPORTING
C10L1/02
CHEMISTRY; METALLURGY
C12M43/04
CHEMISTRY; METALLURGY
C25B15/081
CHEMISTRY; METALLURGY
C10L2290/26
CHEMISTRY; METALLURGY
International classification
B01J19/24
PERFORMING OPERATIONS; TRANSPORTING
C10L1/02
CHEMISTRY; METALLURGY
Abstract
The disclosure provides for the integration of a CO-consuming process, such as a gas fermentation process, with a CO.sub.2 to CO conversion system. The disclosure is capable of utilizing a CO.sub.2-comprising gaseous substrate generated by an industrial process and provides for one or more removal modules to remove at least one constituent from a CO.sub.2-comprising gaseous substrate prior to passage of the gaseous substrate to a CO.sub.2 to CO conversion system. The disclosure may further comprise one or more pressure modules, one or more CO.sub.2 concentration modules, one or more O.sub.2 separation modules, and/or a water electrolysis module. Carbon conversion efficiency is increased by recycling CO.sub.2 produced by a CO-consuming process to the CO.sub.2 to CO conversion process.
Claims
1. A process for improving carbon conversion efficiency comprising: a. passing a CO.sub.2-containing gaseous substrate from an industrial process, a synthesis gas process, or a combination thereof, to at least one removal module for removal of at least one constituent from the CO.sub.2-containing gaseous substrate, to produce a treated gas stream, comprising at least a portion of CO.sub.2; b. passing the treated gas stream to a CO.sub.2 to CO conversion system for conversion of at least a portion of the CO.sub.2 to produce a first CO-enriched stream, wherein the CO.sub.2 to CO conversion system is selected from reverse water gas shift reaction system, thermo-catalytic conversion system, electro-catalytic conversion system, partial combustion system, or plasma conversion system; c. passing at least a portion of the first CO-enriched stream to a bioreactor comprising a culture of at least one C1-fixing microorganism; and d. fermenting the culture to produce one or more fermentation products and a post-fermentation gaseous substrate comprising CO.sub.2 and H.sub.2; e. passing at least a portion of the post-fermentation gaseous substrate comprising CO.sub.2 and H.sub.2 to at least one removal module for removal of at least one constituent from the post-fermentation gaseous substrate to produce a treated gas stream; and f. recycling at least a portion of the treated stream to the CO.sub.2 to CO conversion system.
2. The process of claim 1 wherein the CO.sub.2 to CO conversion system is a reverse water gas shift reaction system and the process further comprising generating a H.sub.2-rich stream using a water electrolyzer and passing and least a portion of the H.sub.2-rich stream to the reverse water gas shift reaction system or to a location upstream of the reverse water gas shift reaction system.
3. The process of claim 1 further comprising passing at least a portion of the post-fermentation gaseous substrate comprising CO.sub.2 and H.sub.2 to at least one removal module for removal of at least one constituent from the post-fermentation gaseous substrate to produce a treated gas stream; and recycling at least a portion of the treated stream to the CO.sub.2 to CO conversion system.
4. The process of claim 1, wherein the industrial process is selected from fermentation, carbohydrate fermentation, sugar fermentation, cellulosic fermentation, gas fermentation, cement making, pulp and paper making, steel making, oil refining, petrochemical production, coke production, anaerobic digestion, aerobic digestion, natural gas extraction, oil extraction, geological reservoirs, metallurgical processes, refinement of aluminium, copper and or ferroalloys, for production of aluminium, copper, and or ferroalloys, direct air capture, or any combination thereof; or the synthesis gas process is selected from gasification of coal, gasification of refinery residues, gasification of petroleum coke, gasification of biomass, gasification of lignocellulosic material, gasification of waste wood, gasification of black liquor, gasification of municipal solid waste, gasification of municipal liquid waste, gasification of industrial solid waste, gasification of industrial liquid waste, gasification of refuse derived fuel, gasification of sewerage, gasification of sewerage sludge, gasification of sludge from wastewater treatment, gasification of biogas, reforming of landfill gas, reforming of biogas, reforming of methane, naphtha reforming, partial oxidation, or any combination thereof.
5. The process of claim 1, further comprising generating a H.sub.2-rich stream using a water electrolyzer and a. blending at least a portion of the H.sub.2-rich stream with the CO-enriched stream prior to being passed to the bioreactor; b. passing and least a portion of the H.sub.2-rich stream to the bioreactor; or c. both a) and b).
6. The process of claim 1, wherein the CO-enriched stream from the CO.sub.2 to CO conversion system is passed to a removal module prior to being passed to the bioreactor.
7. The process of claim 1 wherein the at least one constituent removed from a. the CO-enriched stream; b. the CO.sub.2-containing gas substrate; and or c. the post-fermentation gaseous substrate; is selected from sulfur-comprising compounds, aromatic compounds, alkynes, alkenes, alkanes, olefins, nitrogen-comprising compounds, oxygen, phosphorous-comprising compounds, particulate matter, solids, oxygen, halogenated compounds, silicon-comprising compounds, carbonyls, metals, alcohols, esters, ketones, peroxides, aldehydes, ethers, tars, and naphthalene.
8. The process of claim 7, wherein at least one constituent removed from the CO-enriched stream by the removal module comprises oxygen.
9. The process of claim 1, wherein at least one constituent removed and/or converted is a microbe inhibitor and/or a catalyst inhibitor.
10. The process of claim 1, wherein the at least one constituent removed is produced, introduced, and/or concentrated by the fermentation step.
11. The process of claim 1, wherein at least one constituent removed is produced, introduced, and/or concentrated by the CO.sub.2 to CO conversion system.
12. The process of claim 1, wherein the C1-fixing microorganism is a carboxydotrophic bacterium.
13. The process according to claim 12, wherein the carboxydotrophic bacterium is selected from the group comprising Moorella, Clostridium, Ruminococcus, Acetobacterium, Eubacterium, Butyribacterium, Oxobacter, Methanosarcina, and Desulfotomaculum.
14. The process according to claim 13, wherein the carboxydotrophic bacterium is Clostridium autoethanogenum.
15. The process of claim 1, wherein the CO.sub.2-containing gaseous substrate is passed to a carbon dioxide concentration module to enhance the level of carbon dioxide contained in (i) the CO.sub.2-containing gaseous substrate prior to the CO.sub.2-containing gaseous substrate being passed to the one or more removal module, (ii) the treated gas stream comprising at least a portion of carbon dioxide prior to the treated gas stream being passed to the water electrolyzer; and/or (iii) the post-fermentation gaseous substrate prior to the post-fermentation gaseous substrate being passed to the one or more removal modules, or the bioreactor.
16. The process of claim 1, further comprising passing the CO.sub.2-containing gaseous substrate from the industrial process, the synthesis gas process, or the combination thereof to a pressure module to produce a pressurized CO.sub.2-containing gas stream and then passing the pressurized CO.sub.2-containing gas stream to the first removal module.
17. The process of claim 1, further comprising passing the CO-enriched stream to a pressure module to produce a pressurized CO-stream and passing the pressurized CO-stream to the bioreactor.
18. The process of claim 1, wherein at least one removal module is selected from hydrolysis module, acid gas removal module, deoxygenation module, catalytic hydrogenation module, particulate removal module, chloride removal module, tar removal module, or hydrogen cyanide polishing module.
19. The process of claim 1, wherein at least one of the fermentation products is selected from ethanol, butyrate, 2,3-butanediol, lactate, butene, butadiene, methyl ethyl ketone, ethylene, acetone, isopropanol, lipids, 3-hydroypropionate, terpenes, fatty acids, 2-butanol, 1,2-propanediol, or 1-propanol.
20. The process of claim 1, wherein at least one of the fermentation products is further converted to at least one component of diesel, jet fuel, and/or gasoline.
21. The process of claim 1, wherein at least one of the fermentation products comprises microbial biomass.
22. The process of claim 20, wherein at least a portion of the microbial biomass is processed to produce at least a portion of animal feed.
23. The process of claim 1, wherein the CO-enriched stream comprises at least a portion of oxygen, and at least a portion of the CO-enriched stream is passed to an oxygen separation module to separate at least a portion of oxygen from the carbon monoxide enriched stream.
24. A process for improving process economics of an integrated industrial fermentation system, the process comprising: a. passing a feedstock comprising water to a water electrolyzer, wherein at least a portion of the water is converted to H.sub.2 and O.sub.2; b. passing a CO.sub.2-containing gaseous substrate to a reverse water gas shift process to generate a CO-enriched stream; c. passing at least a portion of the CO-enriched stream from the reverse water gas shift process to a bioreactor containing a culture of at least one C1-fixing microorganism; d. passing at least a portion of the H.sub.2 to the reverse water gas shift process, to the bioreactor, or to both the reverse water gas shift process and the bioreactor; e. fermenting the culture to produce one or more fermentation products and a post-fermentation gaseous substrate comprising CO.sub.2 and H.sub.2; and f. passing at least a portion of the post-fermentation gaseous substrate back to the reverse water gas shift process.
25. The process of claim 24, wherein the amount of CO.sub.2 in the post-fermentation gaseous substrate exiting the bioreactor is greater than an amount of unconverted CO.sub.2 introduced to the bioreactor.
26. The process of claim 24, wherein the fermentation process performs the function of a CO.sub.2 concentration module.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0017]
[0018]
[0019]
[0020]
[0021]
[0022]
[0023]
DETAILED DESCRIPTION
[0024] The inventors have identified that the integration of a CO.sub.2-generating industrial process with a CO-consuming process, as well as a removal process prior to a CO.sub.2 to CO conversion process, is capable of providing substantial benefits to the CO.sub.2-generating industrial process and the CO-consuming process, which may be a C1-fixing fermentation process.
[0025] The term “industrial process” refers to a process for producing, converting, refining, reforming, extracting, or oxidizing a substance involving chemical, physical, electrical, and/or mechanical steps. Exemplary industrial processes include, but are not limited to, carbohydrate fermentation, gas fermentation, cement making, pulp and paper making, steel making, oil refining and associated processes, petrochemical production, coke production, anaerobic or aerobic digestion, gasification (such as gasification of biomass, liquid waste streams, solid waste streams, municipal streams, fossil resources including natural gas, coal and oil), natural gas extraction, oil extraction, metallurgical processes, production and/or refinement of aluminum, copper, and/or ferroalloys, geological reservoirs, Fischer-Tropsch processes, methanol production, pyrolysis, steam methane reforming, dry methane reforming, partial oxidation of biogas or natural gas, direct air capture, and autothermal reforming of biogas or natural gas. In these embodiments, the substrate and/or C1-carbon source may be captured from the industrial process before it is emitted into the atmosphere, using any convenient method.
[0026] The terms “gas from an industrial process,” “gas source from an industrial process,” and “gaseous substrate from an industrial process” can be used interchangeably to refer to an off-gas from an industrial process, a by-product of an industrial process, a co-product of an industrial process, a gas recycled within an industrial process, and/or a gas used within an industrial facility for energy recovery. In some embodiments, a gas from an industrial process is a pressure swing adsorption (PSA) tail gas. In some embodiments, a gas from an industrial process is a gas obtained through a CO.sub.2 extraction process, which may involve amine scrubbing or use of a carbonic anhydrase solution.
[0027] “C1” refers to a one-carbon molecule, for example, CO, CO.sub.2, methane (CH.sub.4), or methanol (CH.sub.3OH). “C1-oxygenate” refers to a one-carbon molecule that also comprises at least one oxygen atom, for example, CO, CO.sub.2, or CH.sub.3OH. “C1-carbon source” refers a one carbon-molecule that serves as a partial or sole carbon source for a microorganism of the disclosure. For example, a C1-carbon source may comprise one or more of CO, CO.sub.2, CH.sub.4, CH.sub.3OH, or formic acid (CH.sub.2O.sub.2). Preferably, a C1-carbon source comprises one or both of CO and CO.sub.2. A “C1-fixing microorganism” is a microorganism that has the ability to produce one or more products from a C1-carbon source. Typically, a microorganism of the disclosure is a C1-fixing bacterium.
[0028] “Substrate” refers to a carbon and/or energy source. Typically, the substrate is gaseous and comprises a C1-carbon source, for example, CO, CO.sub.2, and/or CH.sub.4. Preferably, the substrate comprises a C1-carbon source of CO or CO and CO.sub.2. The substrate may further comprise other non-carbon components, such as H.sub.2, N.sub.2, or electrons. As used herein, “substrate” may refer to a carbon and/or energy source for a microorganism of the disclosure.
[0029] The term “co-substrate” refers to a substance that, while not necessarily being the primary energy and material source for product synthesis, can be utilized for product synthesis when combined with another substrate, such as the primary substrate.
[0030] A “CO.sub.2-comprising gaseous substrate,” “CO.sub.2-comprising gas,” or “CO.sub.2-comprising gaseous source” may include any gas that comprises CO.sub.2. The gaseous substrate will typically comprise a significant proportion of CO.sub.2, preferably at least about 5% to about 100% CO.sub.2 by volume. Additionally, the gaseous substrate may comprise one or more of hydrogen (H.sub.2), oxygen (O.sub.2), nitrogen (N.sub.2), and/or CH.sub.4. As used herein, CO, H.sub.2, and CH.sub.4 may be referred to as “energy-rich gases.”
[0031] The term “carbon capture” as used herein refers to the sequestration of carbon compounds including CO.sub.2 and/or CO from a stream comprising CO.sub.2 and/or CO and either a) converting the CO.sub.2 and/or CO into products, b) converting the CO.sub.2 and/or CO into substances suitable for long term storage, c) trapping the CO.sub.2 and/or CO in substances suitable for long term storage, or d) a combination of these processes.
[0032] The terms “increasing the efficiency,” “increased efficiency,” and the like refer to an increase in the rate and/or output of a reaction, such as an increased rate of converting the CO.sub.2 and/or CO into products and/or an increased product concentration. When used in relation to a fermentation process, “increasing the efficiency” includes, but is not limited to, increasing one or more of the rate of growth of microorganisms catalyzing a fermentation, the growth and/or product production rate at elevated product concentrations, the volume of desired product produced per volume of substrate consumed, the rate of production or level of production of the desired product, and the relative proportion of the desired product produced compared with other by-products of the fermentation.
[0033] “Reactant” as used herein refers to a substance that is present in a chemical reaction and is consumed during the reaction to produce a product. A reactant is a starting material that undergoes a change during a chemical reaction. In particular embodiments, a reactant includes, but is not limited to, CO and/or H.sub.2. In particular embodiments, a reactant is CO.sub.2.
[0034] A “CO-consuming process” refers to a process wherein CO is a reactant; CO is consumed to produce a product. A non-limiting example of a CO-consuming process is a C1-fixing gas fermentation process. A CO-consuming process may involve a CO.sub.2-producing reaction. For example, a CO-consuming process may result in the production of at least one product, such as a fermentation product, as well as CO.sub.2. In another example, acetic acid production is a CO-consuming process, wherein CO is reacted with methanol under pressure.
[0035] “Gas stream” refers to any stream of substrate which is capable of being passed, for example, from one module to another, from one module to a CO-consuming process, and/or from one module to a carbon capture means.
[0036] Gas streams typically will not be a pure CO.sub.2 stream and will comprise proportions of at least one other component. For instance, each source may have differing proportions of CO.sub.2, CO, H.sub.2, and various constituents. Due to the varying proportions, a gas stream must be processed prior to being introduced to a CO-consuming process. Processing of the gas stream includes the removal and/or conversion of various constituents that may be microbe inhibitors and/or catalyst inhibitors. Preferably, catalyst inhibitors are removed and/or converted prior to being passed to the CO.sub.2 to CO conversion process, and microbe inhibitors are removed and/or converted prior to being passed to a CO-consuming process. Additionally, a gas stream may need to undergo one or more concentration steps whereby the concentration of CO and/or CO.sub.2 is increased. Preferably, a gas stream will undergo a concentration step to increase the concentration of CO.sub.2 prior to being passed to the CO.sub.2 to CO conversion process. It has been found that higher concentrations of CO.sub.2 being passing into the CO.sub.2 to CO conversion process results in higher concentrations of CO coming out of the CO.sub.2 to CO conversion process.
[0037] “Removal module,” “contaminant removal module,” “clean-up module,” “processing module,” and the like include technologies that are capable of either converting and/or removing at least one constituent from a gas stream. Non-limiting examples of removal modules include hydrolysis modules, acid gas removal modules, deoxygenation modules, catalytic hydrogenation modules, particulate removal modules, chloride removal modules, tar removal modules, and hydrogen cyanide polishing modules.
[0038] The terms “constituents,” “contaminants,” and the like, as used herein, refer to the microbe inhibitors and/or catalyst inhibitors that may be found in a gas stream. In particular embodiments, the constituents include, but are not limited to, sulfur-comprising compounds, aromatic compounds, alkynes, alkenes, alkanes, olefins, nitrogen-comprising compounds, phosphorous-comprising compounds, particulate matter, solids, oxygen, halogenated compounds, silicon-comprising compounds, carbonyls, metals, alcohols, esters, ketones, peroxides, aldehydes, ethers, tars, and naphthalene. Preferably, the constituent removed by the removal module does not include CO.sub.2.
[0039] “Microbe inhibitors” as used herein refer to one or more constituents that slow down or prevent a particular chemical reaction or other process, including the microbe. In particular embodiments, the microbe inhibitors include, but are not limited to, oxygen (O.sub.2), hydrogen cyanide (HCN), acetylene (C.sub.2H.sub.2), and BTEX (benzene, toluene, ethyl benzene, xylene).
[0040] “Catalyst inhibitor,” “adsorbent inhibitor,” and the like, as used herein, refer to one or more substances that decrease the rate of or prevent a chemical reaction. In particular embodiments, the catalyst inhibitors may include, but are not limited to, hydrogen sulfide (H.sub.2S) and carbonyl sulfide (COS).
[0041] In certain instances, at least one constituent removed is produced, introduced, and/or concentrated by a fermentation step. One or more of these constituents may be present in a post-fermentation gaseous substrate. For example, sulfur, in the form of H.sub.2S may be produced, introduced, and/or concentrated by a fermentation step. In particular embodiments, hydrogen sulfide is introduced in the fermentation step. In various embodiments, the post-fermentation gaseous substrate comprises at least a portion of hydrogen sulfide. Hydrogen sulfide may be a catalyst inhibitor. Hydrogen sulfide may be inhibiting to particular the CO.sub.2 to CO conversion process, if employed. In order to pass a non-inhibiting post-fermentation gaseous substrate to a CO.sub.2 to CO conversion process, at least a portion of the hydrogen sulfide, or other constituent present in the post-fermentation gaseous substrate, may need to be removed by one or more removal module. In another embodiment, acetone may be produced by a fermentation step, and charcoal may be used as a removal module.
[0042] The terms “treated gas” and “treated gas stream” refer to a gas stream that has been passed through at least one removal module and has had one or more constituent removed and/or converted. For example, a “CO.sub.2-treated gas stream” refers to a CO.sub.2-comprising gas that has passed through one or more removal module.
[0043] “Concentration module” and the like refer to technology capable of increasing the level of a particular component in a gas stream. In particular embodiments, the concentration module is a CO.sub.2 concentration module, wherein the proportion of CO.sub.2 in the gas stream leaving the CO.sub.2 concentration module is higher relative to the proportion of CO.sub.2 in the gas stream prior to being passed to the CO.sub.2 concentration module. In some embodiments, a CO.sub.2 concentration module uses deoxygenation technology to remove O.sub.2 from a gas stream and thus increase the proportion of CO.sub.2 in the gas stream. In some embodiments, a CO.sub.2 concentration module uses pressure swing adsorption (PSA) technology to remove H.sub.2 from a gas stream and thus increase the proportion of CO.sub.2 in the gas stream. In certain instances, a fermentation process performs the function of a CO.sub.2 concentration module. In some embodiments, a gas stream from a concentration module is passed to a carbon capture and sequestration (CCS) unit or an enhanced oil recovery (EOR) unit.
[0044] The term “CO.sub.2 to CO conversion system” as used herein refers to at least one unit selected from reverse water gas reaction system, thermo-catalytic conversion system, electro-catalytic conversion system, partial combustion system and plasma conversion system. Previously, a CO.sub.2 electrolysis module was employed as a process to convert at least some collected CO.sub.2 to CO. However, in some applications electricity may be cost prohibitive, not sustainable, not reliable, or not easily available. Therefore, a need exists for another solution to utilize available CO.sub.2 waste gas. The CO.sub.2 to CO conversion system provides such solution. A particular embodiment the CO.sub.2 to CO conversion system is a reverse water gas reaction unit or system.
[0045] The term “reverse water gas reaction unit”/“rWGR unit” as used herein refers to a unit or system used for producing water from carbon dioxide and hydrogen, with carbon monoxide as a side product. The term “water gas” is defined as a fuel gas consisting mainly of carbon monoxide (CO) and hydrogen (H.sub.2). The term ‘shift’ in water-gas shift means changing the water gas composition (CO:H.sub.2) ratio. The ratio can be increased by adding CO.sub.2 or reduced by adding steam to the reactor. The reverse water gas reaction unit may comprise a single stage or more than one stage. The different stages may be conducted at different temperatures and may use different catalysts.
[0046] The term “thermo-catalytic conversion”, another suitable CO.sub.2 to CO conversion system, refers to a process to disrupt the stable atomic and molecular bonds of CO.sub.2 and other reactants over a catalyst by using thermal energy as the driving force of the reaction to produce CO. Since CO.sub.2 molecules are thermodynamically and chemically stable, if CO.sub.2 is used as a single reactant, large amounts of energy are required. Therefore, often other substances such as hydrogen are used as a co-reactant to make the thermodynamic process easier. Many catalysts are known for the process such as metals and metal oxides as well as nano-sized catalyst metal-organic frameworks. Various carbon materials have been employed as carriers for the catalysts.
[0047] The term “partial combustion system” as used herein refers to a system where oxygen supplies at least a portion of the oxidant requirement for partial oxidation and the reactants carbon dioxide and water present therein are substantially converted to carbon monoxide and hydrogen.
[0048] The term “plasma conversion” refers to CO.sub.2 conversion process, focusing on the combination of plasma with catalysts, called as plasma-catalysis. “Plasma” also called the “fourth state of matter,” is an ionized gas consisting of electrons, various types of ions, radicals, excited atoms, and molecules, besides neutral ground state molecules. The three most common plasma types for CO.sub.2 conversion are: dielectric barrier discharges (DBDs), microwave (MW) plasmas, and gliding arc (GA) plasmas.
[0049] “Plasma conversion system” for CO.sub.2 conversion comprises (i) high process versatility, allowing different kinds of reactions to be carried out (e.g., pure CO.sub.2 splitting, as well as CO.sub.2 conversion in the presence of a H-source, such as CH.sub.4, H.sub.2 or H.sub.2O); (ii) low investment and operating costs; (iii) does not require the use of rare earth metals; (iv) a very modular setting, as plasma reactors scale up linearly with the plant output, allowing on-demand production; and (v) it can be very easily combined with (various kinds of) renewable electricity.
[0050] The terms “electrolysis module” and “electrolyzer” can be used interchangeably to refer to a unit that uses electricity to drive a non-spontaneous reaction. Electrolysis technologies are known in the art. Exemplary processes include alkaline water electrolysis, proton, or anion exchange membrane (PEM, AEM) electrolysis, and solid oxide electrolysis (SOE) (Ursua et al., Proceedings of the IEEE 100(2):410-426, 2012; Jhong et al., Current Opinion in Chemical Engineering 2:191-199, 2013). The term “faradaic efficiency” is a value that references the number of electrons flowing through an electrolyzer and being transferred to a reduced product rather than to an unrelated process. SOE modules operate at elevated temperatures. Below the thermoneutral voltage of an electrolysis module, an electrolysis reaction is endothermic. Above the thermoneutral voltage of an electrolysis module, an electrolysis reaction is exothermic. In some embodiments, an electrolysis module is operated without added pressure. In some embodiments, an electrolysis module is operated at a pressure of 5-10 bar.
[0051] A “CO.sub.2 electrolysis module” refers to a unit capable of splitting CO.sub.2 into CO and O.sub.2 and is defined by the following stoichiometric reaction: 2CO.sub.2+electricity.fwdarw.2CO+O.sub.2. The use of different catalysts for CO.sub.2 reduction impact the end product. Catalysts including, but not limited to, Au, Ag, Zn, Pd, and Ga catalysts, have been shown effective to produce CO from CO.sub.2. In some embodiments, the pressure of a gas stream leaving a CO.sub.2 electrolysis module is approximately 5-7 barg.
[0052] “Water electrolysis module,” and “H.sub.2O electrolysis module” refer to a unit capable of splitting H.sub.2O, in the form of steam, into H.sub.2 and O.sub.2 and is defined by the following stoichiometric reaction: 2H.sub.2O+electricity.fwdarw.2H.sub.2+O.sub.2. A water electrolysis module reduces protons to H.sub.2 and oxidizes O.sup.2− to O.sub.2. H.sub.2 produced by electrolysis can be blended with a C1-comprising gaseous substrate as a means to supply additional feedstock and to improve substrate composition.
[0053] H.sub.2 and CO.sub.2 electrolysis modules have 2 gas outlets. One side of the electrolysis module, the anode, comprises H.sub.2 or CO (and other gases such as unreacted water vapor or unreacted CO.sub.2). The second side, the cathode, comprises O.sub.2 (and potentially other gases). The composition of a feedstock being passed to an electrolysis process may determine the presence of various components in a CO stream. For instance, the presence of inert components, such as CH.sub.4 and/or N.sub.2, in a feedstock may result in one or more of those components being present in the CO-enriched stream. Additionally, in some electrolyzers, O.sub.2 produced at the cathode crosses over to the anode side where CO is generated and/or CO crosses over to the anode side, leading to cross contamination of the desired gas products.
[0054] The term “separation module” is used to refer to a technology capable of dividing a substance into two or more components. For example, an “O.sub.2 separation module” may be used to separate an O.sub.2-comprising gaseous substrate into a stream comprising primarily O.sub.2 (also referred to as an “O.sub.2-enriched stream” or “O.sub.2-rich gas”) and a stream that does not primarily comprise O.sub.2, comprises no O.sub.2, or comprises only trace amounts of O.sub.2 (also referred to as an “O.sub.2-lean stream” or “O.sub.2-depleted stream”).
[0055] The terms “enriched stream,” “rich gas,” “high purity gas,” and the like refer to a gas stream having a greater proportion of a particular component following passage through a module, such as an rWGS unit, as compared to the proportion of the component in the input stream into the module. For example, a “CO-enriched stream” may be produced upon passage of a CO.sub.2-comprising gaseous substrate through a CO.sub.2 to CO conversion system such as a rWGS unit. An “H.sub.2-enriched stream” may be produced upon passage of a water gaseous substrate through a water electrolysis module. An “O.sub.2-enriched stream” emerges automatically from the anode of a CO.sub.2 or water electrolysis module; an “O.sub.2-enriched stream” may also be produced upon passage of an O.sub.2-comprising gaseous substrate through an O.sub.2 separation module. A “CO.sub.2-enriched stream” may be produced upon passage of a CO.sub.2-comprising gaseous substrate through a CO.sub.2 concentration module.
[0056] As used herein, the terms “lean stream,” “depleted gas,” and the like refer to a gas stream having a lesser proportion of a particular component following passage through a module, such as a concentration module or a separation module, as compared to the proportion of the component in the input stream into the module. For example, an O.sub.2-lean stream may be produced upon passage of an O.sub.2-comprising gaseous substrate through an O.sub.2 separation module. The O.sub.2-lean stream may comprise unreacted CO.sub.2 from a CO.sub.2 to CO conversion system. The O.sub.2-lean stream may comprise trace amounts of O.sub.2 or no O.sub.2. A “CO.sub.2-lean stream” may be produced upon passage of a CO.sub.2-comprising gaseous substrate through a CO.sub.2 concentration module. The CO.sub.2-lean stream may comprise CO, H.sub.2, and/or a constituent such as a microbe inhibitor or a catalyst inhibitor. The CO.sub.2-lean stream may comprise trace amounts of CO.sub.2 or no CO.sub.2.
[0057] In particular embodiments, the disclosure provides an integrated process wherein the pressure of the gas stream is capable of being increased and/or decreased. The term “pressure module” refers to a technology capable of producing (i.e., increasing) or decreasing the pressure of a gas stream. The pressure of the gas may be increased and/or decreased through any suitable means, for example one or more compressor and/or valve. In certain instances, a gas stream may have a lower than optimum pressure, or the pressure of the gas stream may be higher than optimal, and thus, a valve may be included to reduce the pressure. A pressure module may be located before or after any module described herein. For example, a pressure module may be utilized prior to a removal module, prior to a concentration module, prior to a water electrolysis module, and/or prior to a CO-consuming process.
[0058] A “pressurized gas stream” refers to a gaseous substrate that has passed through a pressure module. A “pressurized gas stream” may also be used to refer to a gas stream that meets the operating pressure requirements of a particular module.
[0059] The terms “post-CO-consuming process gaseous substrate,” “post-CO-consuming process tail gas,” “tail gas,” and the like may be used interchangeably to refer to a gas that has passed through a CO-consuming process. The post-CO-consuming process gaseous substrate may comprise unreacted CO, unreacted H.sub.2, and/or CO.sub.2 produced (or not taken up in parallel) by the CO-consuming process. The post-CO-consuming process gaseous substrate may further be passed to one or more pressure modules, a removal module, a CO.sub.2 concentration module, and/or a water electrolysis module. In some embodiments, a “post-CO-consuming process gaseous substrate” is a post-fermentation gaseous substrate.
[0060] The term “desired composition” is used to refer to the desired level and types of components in a substance, such as, for example, of a gas stream. More particularly, a gas is considered to have a “desired composition” if it contains a particular component (i.e., CO, H.sub.2, and/or CO.sub.2) and/or contains a particular component at a particular proportion and/or does not comprise a particular component (i.e., a contaminant harmful to the microorganisms) and/or does not comprise a particular component at a particular proportion. More than one component may be considered when determining whether a gas stream has a desired composition.
[0061] While it is not necessary for the substrate to comprise any H.sub.2, the presence of H.sub.2 should not be detrimental to product formation in accordance with methods of the disclosure. In particular embodiments, the presence of H.sub.2 results in an improved overall efficiency of alcohol production. In one embodiment, the substrate comprises about 30% or less H.sub.2 by volume, 20% or less H.sub.2 by volume, about 15% or less H.sub.2 by volume or about 10% or less H.sub.2 by volume. In other embodiments, the substrate stream comprises low concentrations of H.sub.2, for example, less than 5%, or less than 4%, or less than 3%, or less than 2%, or less than 1%, or is substantially H.sub.2 free.
[0062] The substrate may also comprise some CO for example, such as about 1% to about 80% CO by volume, or 1% to about 30% CO by volume. In one embodiment, the substrate comprises less than or equal to about 20% CO by volume. In another embodiment, the substrate comprises less than or equal to about 15% CO by volume, less than or equal to about 10% CO by volume, less than or equal to about 5% CO by volume or substantially no CO.
[0063] Substrate composition can be improved to provide a desired or optimum H.sub.2:CO:CO.sub.2 ratio. The desired H.sub.2:CO:CO.sub.2 ratio is dependent on the desired fermentation product of the fermentation process. For ethanol, the optimum H.sub.2:CO:CO.sub.2 ratio would be:
where x>2y, in order to satisfy the stoichiometry for ethanol production:
[0064] Operating the fermentation process in the presence of H.sub.2 has the added benefit of reducing the amount of CO.sub.2 produced by the fermentation process. For example, a gaseous substrate comprising minimal H.sub.2 will typically produce ethanol and CO.sub.2 by the following stoichiometry: 6 CO+3H.sub.2O.fwdarw.C.sub.2H.sub.5OH+4 CO.sub.2. As the amount of H.sub.2 utilized by the C1 fixing bacterium increase, the amount of CO.sub.2 produced decreases, i.e., 2 CO+4H.sub.2.fwdarw.C.sub.2H.sub.5OH+H.sub.2O.
[0065] When CO is the sole carbon and energy source for ethanol production, a portion of the carbon is lost to CO.sub.2 as follows:
6CO+3H.sub.2O.fwdarw.C.sub.2H.sub.5OH+4CO.sub.2 (ΔG°=−224.90 kJ/mol ethanol)
[0066] As the amount of H.sub.2 available in the substrate increases, the amount of CO.sub.2 produced decreases. At a stoichiometric ratio of 1:2 (CO/H.sub.2), CO.sub.2 production is completely avoided.
5CO+1H.sub.2+2H.sub.2O.fwdarw.1C.sub.2H.sub.5OH+3CO.sub.2 (ΔG°=−204.80 kJ/mol ethanol)
4CO+2H.sub.2+1H.sub.2O.fwdarw.1C.sub.2H.sub.5OH+2CO.sub.2 (ΔG°=−184.70 kJ/mol ethanol)
3CO+3H.sub.2.fwdarw.1C.sub.2H.sub.5OH+1CO.sub.2 (ΔG°=−164.60 kJ/mol ethanol)
[0067] The composition of the substrate may have a significant impact on the efficiency and/or cost of the reaction. For example, the presence of O.sub.2 may reduce the efficiency of an anaerobic fermentation process. Depending on the composition of the substrate, it may be desirable to treat, scrub, or filter the substrate to remove any undesired impurities, such as toxins, undesired components, or dust particles, and/or increase the concentration of desirable components. Furthermore, carbon capture can be increased by recycling CO.sub.2 produced by a CO-consuming process back to a CO.sub.2 to CO conversion system, thereby improving yield of the CO-consuming process. CO.sub.2 produced by the CO-consuming process may be treated prior to passage through the CO.sub.2 to CO conversion system. In one embodiment the CO.sub.2 to CO conversion system is a rWGS unit, which can be single stage or two or more stages.
[0068] In some embodiments, a CO-consuming process is performed in a bioreactor. The term “bioreactor” includes a fermentation device consisting of one or more vessels and/or towers or piping arrangements, which includes the Continuous Stirred Tank Reactor (CSTR), Immobilized Cell Reactor (ICR), Trickle Bed Reactor (TBR), Bubble Column, Gas Lift Fermenter, Static Mixer, a circulated loop reactor, a membrane reactor, such as a Hollow Fiber Membrane Bioreactor (HFM BR) or other vessel or other device suitable for gas-liquid contact. The reactor is preferably adapted to receive a gaseous substrate comprising CO, CO.sub.2, H.sub.2, or mixtures thereof. The reactor may comprise multiple reactors (stages), either in parallel or in series. For example, the reactor may comprise a first growth reactor in which the bacteria are cultured and a second fermentation reactor, to which fermentation broth from the growth reactor may be fed and in which most of the fermentation products may be produced.
[0069] Operating a bioreactor at elevated pressures allows for an increased rate of gas mass transfer from the gas phase to the liquid phase. Accordingly, it is generally preferable to perform the culture/fermentation at pressures higher than atmospheric pressure. Also, since a given gas conversion rate is, in part, a function of the substrate retention time and retention time dictates the required volume of a bioreactor, the use of pressurized systems can greatly reduce the volume of the bioreactor required and, consequently, the capital cost of the culture/fermentation equipment. This, in turn, means that the retention time, defined as the liquid volume in the bioreactor divided by the input gas flow rate, can be reduced when bioreactors are maintained at elevated pressure rather than atmospheric pressure. The optimum reaction conditions will depend partly on the particular microorganism used. However, in general, it is preferable to operate the fermentation at a pressure higher than atmospheric pressure. Also, since a given gas conversion rate is in part a function of substrate retention time and achieving a desired retention time in turn dictates the required volume of a bioreactor, the use of pressurized systems can greatly reduce the volume of the bioreactor required, and consequently the capital cost of the fermentation equipment.
[0070] Unless the context requires otherwise, the phrases “fermenting,” “fermentation process,” “fermentation reaction” and the like, as used herein, are intended to encompass both the growth phase and product biosynthesis phase of the gaseous substrate. In certain embodiments, the fermentation is performed in the absence of carbohydrate substrates, such as sugar, starch, lignin, cellulose, or hemicellulose.
[0071] A culture is generally maintained in an aqueous culture medium that contains nutrients, vitamins, and/or minerals sufficient to permit growth of a microorganism. “Nutrient media,” “nutrient medium,” and “culture medium” are used to describe bacterial growth media. Preferably, the aqueous culture medium is an anaerobic microbial growth medium, such as a minimal anaerobic microbial growth medium. Suitable media are well known in the art. The term “nutrient” includes any substance that may be utilised in a metabolic pathway of a microorganism. Exemplary nutrients include potassium, B vitamins, trace metals, and amino acids.
[0072] The terms “fermentation broth” and “broth” are intended to encompass the mixture of components including nutrient media and a culture or one or more microorganisms. It should be noted that the term microorganism and the term bacteria are used interchangeably herein.
[0073] A microorganism of the disclosure may be cultured with a gas stream to produce one or more products. For instance, a microorganism of the disclosure 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), fatty acids (WO 2013/191567), 2-butanol (WO 2013/185123), 1,2-propanediol (WO 2014/036152), 1-propanol (WO 2014/0369152), chorismate-derived products (WO 2016/191625), 3-hydroxybutyrate (WO 2017/066498), 1,3-butanediol (WO 2017/0066498), and 2,3-butanediol (WO2016/094334). In addition to one or more target products, a microorganism of the disclosure may also produce ethanol, acetate, and/or 2,3-butanediol. In certain embodiments, 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. Additionally, the microbial biomass may be further processed to produce a single cell protein (SCP).
[0074] A “microorganism” is a microscopic organism, especially a bacterium, archea, virus, or fungus. A microorganism of the disclosure is typically a bacterium. As used herein, recitation of “microorganism” should be taken to encompass “bacterium.”
[0075] A “parental microorganism” is a microorganism used to generate a microorganism of the disclosure. The parental microorganism may be a naturally occurring microorganism, known as a wild-type microorganism, or a microorganism that has been previously modified, known as a mutant or recombinant microorganism. A microorganism of the disclosure may be modified to express or overexpress one or more enzymes that were not expressed or overexpressed in the parental microorganism. Similarly, a microorganism of the disclosure may be modified to comprise one or more genes that were not contained by the parental microorganism. A microorganism of the disclosure may also be modified to not express or to express lower amounts of one or more enzymes that were expressed in the parental microorganism. In one embodiment, the parental microorganism is Clostridium autoethanogenum, Clostridium ljungdahlii, or Clostridium ragsdalei. In an embodiment, the parental microorganism is Clostridium autoethanogenum LZ1561, which was deposited on Jun. 7, 2010 with Deutsche Sammlung von Mikroorganismen and Zellkulturen GmbH (DSMZ) located at Inhoffenstraβe 7B, D-38124 Braunschweig, Germany on Jun. 7, 2010 under the terms of the Budapest Treaty and accorded accession number DSM23693. This strain is described in International Patent Application No. PCT/NZ2011/000144, which published as WO 2012/015317.
[0076] The term “derived from” indicates that a nucleic acid, protein, or microorganism is modified or adapted from a different, such as a parental or wild-type, nucleic acid, protein, or microorganism, so as to produce a new nucleic acid, protein, or microorganism. Such modifications or adaptations typically include insertion, deletion, mutation, or substitution of nucleic acids or genes. Generally, a microorganism of the disclosure is derived from a parental microorganism. In one embodiment, a microorganism of the disclosure is derived from Clostridium autoethanogenum, Clostridium ljungdahlii, or Clostridium ragsdalei. In an embodiment, a microorganism of the disclosure is derived from Clostridium autoethanogenum LZ1561, which is deposited under DSMZ accession number DSM23693.
[0077] A microorganism of the disclosure may be further classified based on functional characteristics. For example, the microorganism of the disclosure may be or may be derived from a C1-fixing microorganism, an anaerobe, an acetogen, an ethanologen, a carboxydotroph, and/or a methanotroph.
[0078] “Wood-Ljungdahl” refers to the Wood-Ljungdahl pathway of carbon fixation as described, i.e., by Ragsdale, Biochim Biophys Acta, 1784: 1873-1898, 2008. “Wood-Ljungdahl microorganisms” refers, predictably, to microorganisms comprising the Wood-Ljungdahl pathway. Generally, a microorganism of the disclosure contains a native Wood-Ljungdahl pathway. Herein, a Wood-Ljungdahl pathway may be a native, unmodified Wood-Ljungdahl pathway or it may be a Wood-Ljungdahl pathway with some degree of genetic modification (i.e., overexpression, heterologous expression, knockout, etc.) so long as it still functions to convert CO, CO.sub.2, and/or H.sub.2 to acetyl-CoA.
[0079] An “anaerobe” is a microorganism that does not require O.sub.2 for growth. An anaerobe may react negatively or even die if O.sub.2 is present above a certain threshold. However, some anaerobes can tolerate low levels of O.sub.2 (i.e., 0.000001-5% O.sub.2). Typically, a microorganism of the disclosure is an anaerobe.
[0080] “Acetogens” are obligately anaerobic bacteria that use the Wood-Ljungdahl pathway as their main mechanism for energy conservation and for synthesis of acetyl-CoA and acetyl-CoA-derived products, such as acetate (Ragsdale, Biochim Biophys Acta, 1784: 1873-1898, 2008). In particular, acetogens use the Wood-Ljungdahl pathway as a (1) mechanism for the reductive synthesis of acetyl-CoA from CO.sub.2, (2) terminal electron-accepting, energy conserving process, (3) mechanism for the fixation (assimilation) of CO.sub.2 in the synthesis of cell carbon (Drake, Acetogenic Prokaryotes, In: The Prokaryotes, 3.sup.rd edition, p. 354, New York, N.Y., 2006). All naturally occurring acetogens are C1-fixing, anaerobic, autotrophic, and non-methanotrophic. Typically, a microorganism of the disclosure is an acetogen.
[0081] An “ethanologen” is a microorganism that produces or is capable of producing ethanol. Typically, a microorganism of the disclosure is an ethanologen.
[0082] An “autotroph” is a microorganism capable of growing in the absence of organic carbon. Instead, autotrophs use inorganic carbon sources, such as CO and/or CO.sub.2. Typically, a microorganism of the disclosure is an autotroph.
[0083] A “carboxydotroph” is a microorganism capable of utilizing CO as a sole source of carbon and energy. Typically, a microorganism of the disclosure is a carboxydotroph.
[0084] A “methanotroph” is a microorganism capable of utilizing methane as a sole source of carbon and energy. In certain embodiments, a microorganism of the disclosure is a methanotroph or is derived from a methanotroph. In other embodiments, a microorganism of the disclosure is not a methanotroph or is not derived from a methanotroph.
[0085] Table 1 provides a representative list of microorganisms and identifies their functional characteristics.
TABLE-US-00001 TABLE 1 Table 1 Wood-Ljungdahl C1-fixing Anaerobe Acetogen Ethanologen Autotroph Carboxydotroph Acetobacterium woodii + + + + +/− .sup.1 + − Alkalibaculum bacchii + + + + + + + Blautia producta + + + + − + + Butyribacterium methylotrophicum + + + + + + + Clostridium aceticum + + + + − + + Clostridium autoethanogenum + + + + + + + Clostridium carboxidivorans + + + + + + + Clostridium coskatii + + + + + + + Clostridium drakei + + + + − + + Clostridium formicoaceticum + + + + − + + Clostridium ljungdahlii + + + + + + + Clostridium magnum + + + + − + +/− .sup.2 Clostridium ragsdalei + + + + + + + Clostridium scatologenes + + + + − + + Eubacterium limosum + + + + − + + Moorella thermautotrophica + + + + + + + Moorella thermoacetica (formerly + + + + .sup. − .sup.3 + + Clostridium thermoaceticum) Oxobacter pfennigii + + + + − + + Sporomusa ovata + + + + − + +/− .sup.4 Sporomusa silvacetica + + + + − + +/− .sup.5 Sporomusa sphaeroides + + + + − + +/− .sup.6 Thermoanaerobacter kivui + + + + − + − .sup.1 Acetobacterium woodii can produce ethanol from fructose, but not from gas. .sup.2 It has not been investigated whether Clostridium magnum can grow on CO. .sup.3 One strain of Moorella thermoacetica, Moorella sp. HUC22-1, has been reported to produce ethanol from gas. .sup.4 It has not been investigated whether Sporomusa ovata can grow on CO. .sup.5 It has not been investigated whether Sporomusa silvacetica can grow on CO. .sup.6 It has not been investigated whether Sporomusa sphaeroides can grow on CO.
[0086] A “native product” is a product produced by a genetically unmodified microorganism. For example, ethanol, acetate, and 2,3-butanediol are native products of Clostridium autoethanogenum, Clostridium ljungdahlii, and Clostridium ragsdalei. A “non-native product” is a product that is produced by a genetically modified microorganism but is not produced by a genetically unmodified microorganism from which the genetically modified microorganism is derived.
[0087] “Selectivity” refers to the ratio of the production of a target product to the production of all fermentation products produced by a microorganism. A microorganism of the disclosure may be engineered to produce products at a certain selectivity or at a minimum selectivity. In one embodiment, a target product account for at least about 5%, 10%, 15%, 20%, 30%, 50%, or 75% of all fermentation products produced by a microorganism of the disclosure. In one embodiment, the target product accounts for at least 10% of all fermentation products produced by a microorganism of the disclosure, such that a microorganism of the disclosure has a selectivity for the target product of at least 10%. In another embodiment, the target product accounts for at least 30% of all fermentation products produced by a microorganism of the disclosure, such that a microorganism of the disclosure has a selectivity for the target product of at least 30%.
[0088] A culture/fermentation should desirably be carried out under appropriate conditions for production of the target product. Typically, the culture/fermentation is performed under anaerobic conditions. Reaction conditions to consider include pressure (or partial pressure), temperature, gas flow rate, liquid flow rate, media pH, media redox potential, agitation rate (if using a continuous stirred tank reactor), inoculum level, maximum gas substrate concentrations to ensure that gas in the liquid phase does not become limiting, and maximum product concentrations to avoid product inhibition. In particular, the rate of introduction of the substrate may be controlled to ensure that the concentration of gas in the liquid phase does not become limiting, since products may be consumed by the culture under gas-limited conditions.
[0089] Target products may be separated or purified from a fermentation broth using any method or combination of methods known in the art, including, for example, fractional distillation, evaporation, pervaporation, gas stripping, phase separation, and extractive fermentation, including for example, liquid-liquid extraction. In certain embodiments, target products are recovered from the fermentation broth by continuously removing a portion of the broth from the bioreactor, separating microbial cells from the broth (conveniently by filtration), and recovering one or more target products from the broth. Alcohols and/or acetone may be recovered, for example, by distillation. Acids may be recovered, for example, by adsorption on activated charcoal. Separated microbial cells are preferably returned to the bioreactor. The cell-free permeate remaining after target products have been removed is also preferably returned to the bioreactor. Additional nutrients (such as B vitamins) may be added to the cell-free permeate to replenish the medium before it is returned to the bioreactor.
[0090]
[0091] The CO-consuming process 140 of
[0092] In some embodiments, the CO-consuming process 140 of
[0093] In particular embodiments, at least one constituent removed by the removal module 150 of
[0094] The O.sub.2 by-product of water electrolysis processes employed, for example when the CO.sub.2 to CO conversion process is a rWGS unit, can provide additional benefits for the C1-generating industrial process, discussed above. Specific embodiments of the fermentation processes of the current disclosure are anaerobic processes, and depending upon the technology selected for the CO.sub.2 to CO conversion system, O.sub.2 could be generated as a by-product and may be separated and passed through optional conduit 136 in of
[0095] Typically, the industrial processes described herein derive the required O.sub.2 by air separation. Production of O.sub.2 by air separation is an energy intensive process which involves cryogenically separating O.sub.2 from N.sub.2 to achieve the highest purity. Production of O.sub.2 by CO.sub.2 conversion to CO as in line 136, depending upon the CO.sub.2 to CO conversion system selected, and/or water electrolysis as in line 166, and displacing O.sub.2 produced by air separation, could offset up to 5% of the electricity costs in an industrial process.
[0096] Several C1-generating industrial processes involving partial oxidation reactions require an O.sub.2 input. Exemplary industrial processes include Basic Oxygen Furnace (BOF) reactions, COREX or FINEX steel making processes, Blast Furnace (BF) processes, ferroalloy production processes, non-ferrous products manufacturing, petroleum refining, petrochemical production, carbohydrate fermentation, cement making, titanium dioxide production processes, gasification processes and any combinations thereof. Gasification processes include, but are not limited to, gasification of coal, gasification of refinery residues, gasification of biomass, gasification of lignocellulosic material, black liquor gasification, gasification of municipal solid waste, gasification of industrial solid waste, gasification of sewerage, gasification of sludge from wastewater treatment, gasification of pet coke, reforming of natural gas, reforming of biogas, reforming of landfill gas or any combination thereof. In one or more of these industrial processes, O.sub.2 from the CO.sub.2 to CO conversion system and/or O.sub.2 from water electrolysis may be used to off-set or completely replace the O.sub.2 typically supplied through air separation.
[0097] As shown in
[0098]
[0099] In particular embodiments where the CO.sub.2 to CO conversion system generates O.sub.2 by-product, the process includes an O.sub.2 separation module 260 following the CO.sub.2 to CO conversion system 230 to separate at least a portion of O.sub.2 from the gas generated in CO.sub.2 to CO conversion system 230. In embodiments utilizing an O.sub.2 separation module 260 downstream of CO.sub.2 to CO conversion system 230, at least a portion of gas stream 234 is fed from the CO.sub.2 to CO conversion system 230 to O.sub.2 separation module 260. In embodiments incorporating O.sub.2 separation module 260, an O.sub.2-enriched stream 264 may be passed industrial process 210 thereby displacing the need for other sources of O.sub.2 in industrial process 210. In embodiments utilizing O.sub.2 separation module 260 downstream of CO.sub.2 to CO conversion system 230, at least a portion of the O.sub.2-lean stream 262 is passed from O.sub.2 separation module 260 to the CO-consuming process 240. In some embodiments utilizing an O.sub.2 separation module 260 downstream of CO.sub.2 to CO conversion system 230, at least a portion of the O.sub.2-lean stream 262 is passed from O.sub.2 separation module 260 back to the CO.sub.2 to CO conversion system 230 in line 266. In embodiments not utilizing an O.sub.2 separation module 260, a portion of the gas stream 236 may be passed from the CO.sub.2 to CO conversion system 230 to the industrial process 210.
[0100] In some embodiments, the CO-consuming process 240 of
[0101] The CO-consuming process 240 of
[0102] Providing a high purity CO.sub.2 stream, a CO.sub.2-rich stream, to a CO.sub.2 to CO conversion system, such as a rWGS unit, increases the carbon capture efficiency of a CO-consuming process. To increase the concentration of CO.sub.2 in a stream, one or more CO.sub.2 concentration module may be incorporated in the process. The CO-enriched stream generated by the CO.sub.2 to CO conversion system, such as a rWGS unit, stream may have a concentration of CO between 20-90%.
[0103]
[0104] At least a portion of the gas stream 336 from the CO.sub.2 to CO conversion system 330 may be passed to the industrial process 310. In particular embodiments, the process includes an O.sub.2 separation module 360 following the CO.sub.2 to CO conversion system 330, where the gas stream 334 is passed from the CO.sub.2 to CO conversion system 330 to the O.sub.2 separation module 360 to separate at least a portion of O.sub.2 from the gas stream 334. In embodiments utilizing O.sub.2 separation module 360 after the CO.sub.2 to CO conversion system 330, at least a portion of the O.sub.2-enriched stream 364 is passed from O.sub.2 separation module 360 to industrial process 310. In embodiments utilizing an O.sub.2 separation module 360 after the CO.sub.2 to CO conversion system 330, at least a portion of the O.sub.2-lean stream 362 is passed from O.sub.2 separation module 360 to CO-consuming process 340. In some embodiments utilizing an O.sub.2 separation module 360 after the CO.sub.2 to CO conversion system 330, at least a portion of the O.sub.2-lean stream 366 is passed from the O.sub.2 separation module 260 back to CO.sub.2 to CO conversion system 330. In embodiments not utilizing an O.sub.2 separation module 360, a portion of the gas stream 336 may be passed from the CO.sub.2 to CO conversion system 330 to industrial process 310.
[0105] Concentrating the CO.sub.2 in the gas stream 314 prior to the one or more removal modules 320 decreases undesired gases and thereby increases the efficiency of the CO-consuming process 340, which may be a gas fermentation process.
[0106] In some embodiments, the CO-consuming process 340 of
[0107] The CO-consuming process 340 of
[0108] In particular embodiments, a CO.sub.2 concentration module may be placed after a removal module.
[0109] At least a portion of the gas stream 436 from the CO.sub.2 to CO conversion system 430 may be passed to the industrial process 410. In particular embodiments, the process includes O.sub.2 separation module 460 following the CO.sub.2 to CO conversion system 430 to separate at least a portion of O.sub.2 from the gas stream 434. In embodiments utilizing an O.sub.2 separation module 460 after the CO.sub.2 to CO conversion system 430, at least a portion of the gas stream 464 is fed from the O.sub.2 separation module 460 to the industrial process 410. In embodiments utilizing O.sub.2 separation module 460 after the CO.sub.2 to CO conversion system 430, at least a portion of the O.sub.2-lean stream 462 is passed from O.sub.2 separation module 460 to CO-consuming process 440. In some embodiments utilizing O.sub.2 separation module 460 after CO.sub.2 to CO conversion system 430, at least a portion of the O.sub.2-lean stream 466 is passed from the O.sub.2 separation module 460 back to the CO.sub.2 to CO conversion system 430. In embodiments not utilizing O.sub.2 separation module 460, a portion of the gas stream 436 may be passed from the CO.sub.2 to CO conversion system 430 to the industrial process 410, particularly if the selected CO.sub.2 to CO conversion system 430 generates O.sub.2.
[0110] In some embodiments, the CO-consuming process 440 of
[0111] The CO-consuming process 440 of
[0112]
[0113] In particular embodiments, the disclosure provides one or more pressure modules 580 to increase the pressure of the converted gas 532 from the CO.sub.2 to CO conversion system 530. In embodiments utilizing a pressure module 580 after the CO.sub.2 to CO conversion system 530, at least a portion of the gas stream 532 is passed from CO.sub.2 to CO conversion system 530 to pressure module 580 which increases the pressure of gas stream 532 and generates increased pressure stream 582 which is passed to CO-consuming process 540.
[0114] In various embodiments, water electrolysis module 1500 is incorporated along with the O.sub.2 separation module 560 and/or the pressure module 580. In various embodiments, a water substrate 1506 is introduced to water electrolysis module 1500, and H.sub.2-rich gas stream 1502 is blended with the converted gas stream 582 prior to converted gas stream 582 being introduced to CO-consuming process 540. In various embodiments, H.sub.2-rich gas stream 1504 is passed directly from water electrolysis module 1500 to CO-consuming process 540. Depending upon the CO.sub.2 to CO conversion system selected, such as a rWGS unit which uses H.sub.2 as a reactant, an H.sub.2-enriched stream 1510 may be passed from water electrolysis module 1500 to CO.sub.2 to CO conversion system 530. Optionally, at least a portion of O.sub.2-enriched stream 1508 generated by water electrolysis module 1500 may be passed to industrial process 510.
[0115] In certain embodiments, the disclosure integrates an industrial process 510, an optional CO.sub.2 concentration module 570, a removal module 520, a CO.sub.2 to CO conversion system 530, an optional O.sub.2 separation module 560, an optional pressure module 580, an water electrolysis module 1500, and a CO-consuming process 540, in accordance with one aspect of the disclosure. CO.sub.2-comprising gas 514 from the industrial process 510 is passed to an optional CO.sub.2 concentration module 570 to increase the concentration of the CO.sub.2 in the gas stream 514 and remove one or more constituent 574. A first CO.sub.2 concentrated stream 572 from first CO.sub.2 concentration module 570 is passed to removal module 520 to remove and/or convert one or more constituent 528. The treated stream 524 is then passed to a second optional CO.sub.2 concentration module 570 to increase the concentration of the CO.sub.2 in the gas stream 524 and remove one or more constituent 574. A second CO.sub.2 concentrated stream 572 is passed to a CO.sub.2 to CO conversion system 530 for conversion of at least a portion of the second CO.sub.2 concentrated stream 572. At least a portion of the converted gas stream 534 may be passed to an optional O.sub.2 separation module 560 to separate at least a portion of O.sub.2 from the converted gas stream 534. At least a portion of the O.sub.2-rich gas stream 564 may be passed from the optional O.sub.2 separation module 560 to the industrial process 510. At least a portion of the O.sub.2-rich gas stream may be fed from the CO.sub.2 to CO conversion system 530 to the industrial process 510 via a conduit 536, if the selected CO.sub.2 to CO conversion system 530 generates O.sub.2. At least a portion of the O.sub.2-depleted gas stream 562 may be passed from the optional O.sub.2 separation module 560 to an optional pressure module 580. The pressurized gas stream 582 from the optional pressure module 580 is passed to the CO-consuming process 540. The pressurized gas stream 582 may be blended with an H.sub.2-rich gas stream 1502 prior to being introduced to the CO-consuming process 540.
[0116] The CO-consuming process 540 of
[0117] The disclosure provides generally for the removal of constituents from the gas stream that may have adverse effects on downstream processes, for instance, the downstream fermentation process and/or downstream modules. In particular embodiments, the disclosure provides for one or more further removal module between the various modules in order to prevent the occurrence of such adverse effects.
[0118] In various instances, the conversion of a CO.sub.2-comprising gaseous substrate by an CO.sub.2 to CO conversion system results in one or more constituent passing through the CO.sub.2 to CO conversion system 630. In various embodiments, this results in one or more constituent in the CO-enriched stream. In certain instances, the constituent includes portions of converted O.sub.2. In various embodiments, the further removal module is a deoxygenation module for removing O.sub.2 from the CO-enriched stream.
[0119]
[0120] In certain embodiments, the disclosure integrates an industrial process 610, an optional CO.sub.2 concentration module 670, a removal module 620, a CO.sub.2 to CO conversion system 630, a further removal module 690, an optional O.sub.2 separation module 660, an optional pressure module 680, an optional water electrolysis module 1600, and a CO-consuming process 640, in accordance with one embodiment of the disclosure. In embodiments not including an optional CO.sub.2 concentration module 670 between the industrial process 610 and the removal module 620, the CO.sub.2-comprising gas 612 from the industrial process 610 is passed to the removal module 620. In embodiments including an optional CO.sub.2 concentration module 670 between the industrial process 610 and the removal module 620, the CO.sub.2-comprising gas 614 from the industrial process 610 is passed to an optional CO.sub.2 concentration module 670 to increase the concentration of the CO.sub.2 in the gas stream 614 and remove one or more constituent 674. The gas stream having increased CO.sub.2 concentration 672 from optional CO.sub.2 concentration module 670 is passed to removal module 620, to remove and/or convert one or more constituents 628. In embodiments not including a CO.sub.2 concentration module 670 between the removal module 620 and the CO.sub.2 to CO conversion system 630, the treated stream 622 is passed from removal module 620 to CO.sub.2 to CO conversion system 630. In embodiments including a CO.sub.2 concentration module 670 between the removal module 620 and the CO.sub.2 to CO conversion system 630, the treated stream 624 is then passed to an optional CO.sub.2 concentration module 670 to increase the concentration of the CO.sub.2 in the treated stream 624 and remove one or more constituents 674. The resulting CO.sub.2 enriched stream 672 is passed from optional CO.sub.2 concentration module 670 to CO.sub.2 to CO conversion system 630 for conversion of at least a portion of CO.sub.2 enriched stream 672.
[0121] Depending upon the CO.sub.2 to CO conversion system 630 selected, O.sub.2 may be generated, and if so, at least a portion of a O.sub.2-rich gas stream 636 may be passed from the CO.sub.2 to CO conversion system 630 to industrial process 610. At least a portion of CO-rich gas stream 632 may be passed to a further removal module 690 to remove and/or convert one or more constituents 698. At least a portion of the treated gas stream 634 may be passed to an optional O.sub.2 separation module 660 to separate at least a portion of O.sub.2 from treated gas stream 634. At least a portion of the O.sub.2-enriched gas stream 664 may be passed from the optional O.sub.2 separation module 660 to the industrial process 610. At least a portion of the O.sub.2-depleted gas stream 662 may be passed from the optional O.sub.2 separation module 660 to the further removal module 690 to remove and/or convert one or more constituents 698.
[0122] At least a portion of the gas stream 692 may be passed from the further removal module 690 to an optional pressure module 680. The pressurized gas stream 682 from the optional pressure module 680 is passed to CO-consuming process 640. The gas stream 692 may be blended with a H.sub.2-rich gas stream 1602 prior to being introduced to the CO-consuming process 640. A water substrate 1606 may be passed a water electrolysis module 1600 to generate H.sub.2-rich gas stream 1602 discussed above, and/or H.sub.2-rich gas stream 1604 which may be passed from water electrolysis module 1600 directly to the CO-consuming process 640 via a conduit 1604. In some embodiments, O.sub.2 produced by the water electrolysis module 1600 may be passed in O.sub.2 stream 1608 to the industrial process 610.
[0123] The CO-consuming process 640 of
[0124] In various embodiments, the disclosure provides an integrated process comprising electrolysis of water to provide at least hydrogen and optionally oxygen, wherein the power supplied for the water electrolysis process is derived, at least in part, from a renewable energy source.
[0125] Although the substrate is typically gaseous, the substrate may also be provided in alternative forms. For example, the substrate may be dissolved in a liquid saturated with a CO-comprising gas using a microbubble dispersion generator. By way of further example, the substrate may be adsorbed onto a solid support.
[0126] The C1-fixing microorganism in a bioreactor is typically a carboxydotrophic bacterium. In particular embodiments, the carboxydotrophic bacterium is selected from the group comprising Moorella, Clostridium, Ruminococcus, Acetobacterium, Eubacterium, Butyribacterium, Oxobacter, Methanosarcina, Methanosarcina, and Desulfotomaculum. In various embodiments, the carboxydotrophic bacterium is Clostridium autoethanogenum.
[0127] 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 acknowledgement that that prior art forms part of the common general knowledge in the field of endeavor in any country.
[0128] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the disclosure (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 (i.e., meaning “including, but not limited to”) unless otherwise noted. The use of the alternative (i.e., “or”) should be understood to mean either one, both, or any combination thereof of the alternatives. As used herein, the term “about” means ±20% of the indicated range, value, or structure, unless otherwise indicated.
[0129] 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 indicated, any concentration range, percentage range, ratio range, integer range, size range, or thickness range is to be understood to include the value of any integer within the recited range and, when appropriate, fractions thereof (such as one tenth and one hundredth of an integer). Unless otherwise indicated, ratios are molar ratios, and percentages are on a weight basis.
[0130] 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 (i.e., “such as”) provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure.
[0131] Embodiments of this disclosure are described herein. Variations of those 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 disclosure to be practiced otherwise than as specifically described herein. Accordingly, this disclosure 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 disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.