Patent Application
20220333140
The disclosure relates to processes and methods for improving carbon conversion efficiency. In particular, the disclosure relates to the combination of a carbon monoxide-consuming process with an industrial process or with syngas, wherein gas from the industrial process or syngas undergoes treatment and conversion, and carbon dioxide produced by the carbon monoxide-consuming process is recycled to increase product yield.
Carbon dioxide (CO2) accounts for about 76% of global greenhouse gas emissions from human activities, with methane (16%), nitrous oxide (6%), and fluorinated gases (2%) accounting for the balance (United States Environmental Protection Agency). Reduction of greenhouse gas emissions, particularly CO2, is critical to halt the progression of global warming and the accompanying shifts in climate and weather.
It has long been recognized that catalytic processes, such as the Fischer-Tropsch process, may be used to convert gases comprising CO2, carbon monoxide (CO), and/or hydrogen (H2) into a variety of fuels and chemicals. Recently, however, gas fermentation has emerged as an alternative platform for the biological fixation of such gases. In particular, C1-fixing microorganisms have been demonstrated to convert gases comprising CO2, CO, CH4, and/or H2 into products such as ethanol and 2,3-butanediol.
Such gases may be derived, for example, from industrial processes, including gas emissions from 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, 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, and autothermal reforming of biogas or natural gas.
To optimize the usage of these gases in CO-consuming processes, such as C1-fixing fermentation processes, an industrial gas may require a combination of treatment and conversion. Accordingly, there remains a need for improved integration of industrial processes with CO-consuming processes, including processes for treatment and conversion of industrial gases, thereby optimizing carbon conversion efficiency.
A process for improving carbon conversion efficiency is disclosed. The process comprises a) passing a CO2-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 CO2-containing gaseous substrate, to produce a treated gas stream, comprising at least a portion of CO2; b) passing the treated gas stream to a CO2 to CO conversion system for conversion of at least a portion of the CO2 to produce a first CO-enriched stream, wherein the CO2 to CO conversion system is selected from reverse water gas 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; d) fermenting the culture to produce one or more fermentation products and a post-fermentation gaseous substrate comprising CO2 and H2; e) passing at least a portion of the post-fermentation gaseous substrate comprising CO2 and H2 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 CO2 to CO conversion system.
The industrial process may be selected from 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.
The H2-rich stream may be generated using a water electrolyzer and at least a portion of the H2-rich stream may be blended with the CO-enriched stream prior to being passed to the bioreactor or at least a portion of the H2-rich stream may be passed to the bioreactor; or both at least a portion of the H2-rich stream may be blended with the CO-enriched stream prior to being passed to the bioreactor and at least a portion of the H2-rich stream may be passed to the bioreactor.
The process the CO-enriched stream from the CO2 to CO conversion system may be passed to a removal module prior to being passed to the bioreactor. The at least one constituent may be removed from a) the CO-enriched stream; b) the CO2-containing gas substrate; and or c) the post-fermentation gaseous substrate; and may be 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. The at least one constituent removed from the CO-enriched stream by the removal module may comprise oxygen. The at least one constituent removed and/or converted may be a microbe inhibitor and/or a catalyst inhibitor. The at least one constituent removed may be produced, introduced, and/or concentrated by the fermentation step. The at least one constituent removed may be produced, introduced, and/or concentrated by the CO2 to CO conversion system.
The C1-fixing microorganism may be a carboxydotrophic bacterium. The carboxydotrophic bacterium may be selected from the group comprising Moorella, Clostridium, Ruminococcus, Acetobacterium, Eubacterium, Butyribacterium, Oxobacter, Methanosarcina, and Desulfotomaculum. The carboxydotrophic bacterium may be Clostridium autoethanogenum.
The CO2-containing gaseous substrate may be passed to a carbon dioxide concentration module to enhance the level of carbon dioxide contained in (i) the CO2-containing gaseous substrate prior to the CO2-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. The CO2-containing gaseous substrate from the industrial process, the synthesis gas process, or the combination thereof may be passed to a pressure module to produce a pressurized CO2-containing gas stream and then passing the pressurized CO2-containing gas stream to the first removal module. The CO-enriched stream may be passed to a pressure module to produce a pressurized CO-stream and the pressurized CO-stream may be passed to the bioreactor.
The at least one removal module may be 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.
The at least one fermentation product may be 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. The at least one of the fermentation product maybe further converted to at least one component of diesel, jet fuel, and/or gasoline. The at least one fermentation product may comprise microbial biomass. At least a portion of the microbial biomass may be processed to produce at least a portion of animal feed.
The CO-enriched stream may comprise at least a portion of oxygen, and at least a portion of the CO-enriched stream may be passed to an oxygen separation module to separate at least a portion of oxygen from the carbon monoxide enriched stream.
A process for improving process economics of an integrated industrial fermentation system is also disclosed. The process comprises a) passing a feedstock comprising water to a water electrolyzer, wherein at least a portion of the water is converted to H2 and O2; b) passing a CO2-containing gaseous substrate to a reverse water gas shift process to generate a CO-enriched stream; c) passing at least a portion of the H2 and 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) fermenting the culture to produce one or more fermentation products and a post-fermentation gaseous substrate comprising CO2 and H2; and e) passing at least a portion of the post-fermentation gaseous substrate back to the reverse water gas shift process. The amount of CO2 in the post-fermentation gaseous substrate exiting the bioreactor may be greater than an amount of unconverted CO2 introduced to the bioreactor. The fermentation process may perform the function of a CO2 concentration module.
The inventors have identified that the integration of a CO2-generating industrial process with a CO-consuming process, as well as a removal process prior to a CO2 to CO conversion process, is capable of providing substantial benefits to the CO2-generating industrial process and the CO-consuming process, which may be a C1-fixing fermentation process.
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.
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 CO2 extraction process, which may involve amine scrubbing or use of a carbonic anhydrase solution.
“C1” refers to a one-carbon molecule, for example, CO, CO2, methane (CH4), or methanol (CH3OH). “C1-oxygenate” refers to a one-carbon molecule that also comprises at least one oxygen atom, for example, CO, CO2, or CH3OH. “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, CO2, CH4, CH3OH, or formic acid (CH2O2). Preferably, a C1-carbon source comprises one or both of CO and CO2. 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.
“Substrate” refers to a carbon and/or energy source. Typically, the substrate is gaseous and comprises a C1-carbon source, for example, CO, CO2, and/or CH4. Preferably, the substrate comprises a C1-carbon source of CO or CO and CO2. The substrate may further comprise other non-carbon components, such as H2, N2, or electrons. As used herein, “substrate” may refer to a carbon and/or energy source for a microorganism of the disclosure.
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.
A “CO2-comprising gaseous substrate,” “CO2-comprising gas,” or “CO2-comprising gaseous source” may include any gas that comprises CO2. The gaseous substrate will typically comprise a significant proportion of CO2, preferably at least about 5% to about 100% CO2 by volume. Additionally, the gaseous substrate may comprise one or more of hydrogen (H2), oxygen (O2), nitrogen (N2), and/or CH4. As used herein, CO, H2, and CH4 may be referred to as “energy-rich gases.”
The term “carbon capture” as used herein refers to the sequestration of carbon compounds including CO2 and/or CO from a stream comprising CO2 and/or CO and either a) converting the CO2 and/or CO into products, b) converting the CO2 and/or CO into substances suitable for long term storage, c) trapping the CO2 and/or CO in substances suitable for long term storage, or d) a combination of these processes.
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 CO2 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.
“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 H2. In particular embodiments, a reactant is CO2.
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 CO2-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 CO2. In another example, acetic acid production is a CO-consuming process, wherein CO is reacted with methanol under pressure.
“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.
Gas streams typically will not be a pure CO2 stream and will comprise proportions of at least one other component. For instance, each source may have differing proportions of CO2, CO, H2, 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 CO2 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 CO2 is increased. Preferably, a gas stream will undergo a concentration step to increase the concentration of CO2 prior to being passed to the CO2 to CO conversion process. It has been found that higher concentrations of CO2 being passing into the CO2 to CO conversion process results in higher concentrations of CO coming out of the CO2 to CO conversion process.
“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.
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 CO2.
“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 (O2), hydrogen cyanide (HCN), acetylene (C2H2), and BTEX (benzene, toluene, ethyl benzene, xylene).
“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 (H2S) and carbonyl sulfide (COS).
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 H2S 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 CO2 to CO conversion process, if employed. In order to pass a non-inhibiting post-fermentation gaseous substrate to a CO2 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.
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 “CO2-treated gas stream” refers to a CO2-comprising gas that has passed through one or more removal module.
“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 CO2 concentration module, wherein the proportion of CO2 in the gas stream leaving the CO2 concentration module is higher relative to the proportion of CO2 in the gas stream prior to being passed to the CO2 concentration module. In some embodiments, a CO2 concentration module uses deoxygenation technology to remove O2 from a gas stream and thus increase the proportion of CO2 in the gas stream. In some embodiments, a CO2 concentration module uses pressure swing adsorption (PSA) technology to remove H2 from a gas stream and thus increase the proportion of CO2 in the gas stream. In certain instances, a fermentation process performs the function of a CO2 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.
The term “CO2 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 CO2 electrolysis module was employed as a process to convert at least some collected CO2 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 CO2 waste gas. The CO2 to CO conversion system provides such solution. A particular embodiment the CO2 to CO conversion system is a reverse water gas reaction unit or system.
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 (H2). The term ‘shift’ in water-gas shift means changing the water gas composition (CO:H2) ratio. The ratio can be increased by adding CO2 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.
The term “thermo-catalytic conversion”, another suitable CO2 to CO conversion system, refers to a process to disrupt the stable atomic and molecular bonds of CO2 and other reactants over a catalyst by using thermal energy as the driving force of the reaction to produce CO. Since CO2 molecules are thermodynamically and chemically stable, if CO2 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.
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.
The term “plasma conversion” refers to CO2 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 CO2 conversion are: dielectric barrier discharges (DBDs), microwave (MW) plasmas, and gliding arc (GA) plasmas.
“Plasma conversion system” for CO2 conversion comprises (i) high process versatility, allowing different kinds of reactions to be carried out (e.g., pure CO2 splitting, as well as CO2 conversion in the presence of a H-source, such as CH4, H2 or H2O); (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.
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.
A “CO2 electrolysis module” refers to a unit capable of splitting CO2 into CO and O2 and is defined by the following stoichiometric reaction: 2CO2+electricity→2CO+O2. The use of different catalysts for CO2 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 CO2. In some embodiments, the pressure of a gas stream leaving a CO2 electrolysis module is approximately 5-7 barg.
“Water electrolysis module,” and “H2O electrolysis module” refer to a unit capable of splitting H2O, in the form of steam, into H2 and O2 and is defined by the following stoichiometric reaction: 2H2O+electricity→2H2+O2. A water electrolysis module reduces protons to H2 and oxidizes O2− to O2. H2 produced by electrolysis can be blended with a C1-comprising gaseous substrate as a means to supply additional feedstock and to improve substrate composition.
H2 and CO2 electrolysis modules have 2 gas outlets. One side of the electrolysis module, the anode, comprises H2 or CO (and other gases such as unreacted water vapor or unreacted CO2). The second side, the cathode, comprises O2 (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 CH4 and/or N2, in a feedstock may result in one or more of those components being present in the CO-enriched stream. Additionally, in some electrolyzers, O2 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.
The term “separation module” is used to refer to a technology capable of dividing a substance into two or more components. For example, an “O2 separation module” may be used to separate an O2-comprising gaseous substrate into a stream comprising primarily O2 (also referred to as an “O2-enriched stream” or “O2-rich gas”) and a stream that does not primarily comprise O2, comprises no O2, or comprises only trace amounts of O2 (also referred to as an “O2-lean stream” or “O2-depleted stream”).
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 CO2-comprising gaseous substrate through a CO2 to CO conversion system such as a rWGS unit. An “H2-enriched stream” may be produced upon passage of a water gaseous substrate through a water electrolysis module. An “O2-enriched stream” emerges automatically from the anode of a CO2 or water electrolysis module; an “O2-enriched stream” may also be produced upon passage of an O2-comprising gaseous substrate through an O2 separation module. A “CO2-enriched stream” may be produced upon passage of a CO2-comprising gaseous substrate through a CO2 concentration module.
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 O2-lean stream may be produced upon passage of an O2-comprising gaseous substrate through an O2 separation module. The O2-lean stream may comprise unreacted CO2 from a CO2 to CO conversion system. The O2-lean stream may comprise trace amounts of O2 or no O2. A “CO2-lean stream” may be produced upon passage of a CO2-comprising gaseous substrate through a CO2 concentration module. The CO2-lean stream may comprise CO, H2, and/or a constituent such as a microbe inhibitor or a catalyst inhibitor. The CO2-lean stream may comprise trace amounts of CO2 or no CO2.
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.
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.
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 H2, and/or CO2 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 CO2 concentration module, and/or a water electrolysis module. In some embodiments, a “post-CO-consuming process gaseous substrate” is a post-fermentation gaseous substrate.
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, H2, and/or CO2) 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.
While it is not necessary for the substrate to comprise any H2, the presence of H2 should not be detrimental to product formation in accordance with methods of the disclosure. In particular embodiments, the presence of H2 results in an improved overall efficiency of alcohol production. In one embodiment, the substrate comprises about 30% or less H2 by volume, 20% or less H2 by volume, about 15% or less H2 by volume or about 10% or less H2 by volume. In other embodiments, the substrate stream comprises low concentrations of H2, for example, less than 5%, or less than 4%, or less than 3%, or less than 2%, or less than 1%, or is substantially H2 free.
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.
Substrate composition can be improved to provide a desired or optimum H2:CO:CO2 ratio. The desired H2:CO:CO2 ratio is dependent on the desired fermentation product of the fermentation process. For ethanol, the optimum H2:CO:CO2 ratio would be:
where x>2y, in order to satisfy the stoichiometry for ethanol production:
Operating the fermentation process in the presence of H2 has the added benefit of reducing the amount of CO2 produced by the fermentation process. For example, a gaseous substrate comprising minimal H2 will typically produce ethanol and CO2 by the following stoichiometry: 6 CO+3H2O→C2H5OH+4 CO2. As the amount of H2 utilized by the C1 fixing bacterium increase, the amount of CO2 produced decreases, i.e., 2 CO+4H2→C2H5OH+H2O.
When CO is the sole carbon and energy source for ethanol production, a portion of the carbon is lost to CO2 as follows:
6CO+3H2O→C2H5OH+4CO2 (ΔG°=−224.90 kJ/mol ethanol)
As the amount of H2 available in the substrate increases, the amount of CO2 produced decreases. At a stoichiometric ratio of 1:2 (CO/H2), CO2 production is completely avoided.
5CO+1H2+2H2O→1C2H5OH+3CO2 (ΔG°=−204.80 kJ/mol ethanol)
4CO+2H2+1H2O→1C2H5OH+2CO2 (ΔG°=−184.70 kJ/mol ethanol)
3CO+3H2→1C2H5OH+1CO2 (ΔG°=−164.60 kJ/mol ethanol)
The composition of the substrate may have a significant impact on the efficiency and/or cost of the reaction. For example, the presence of O2 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 CO2 produced by a CO-consuming process back to a CO2 to CO conversion system, thereby improving yield of the CO-consuming process. CO2 produced by the CO-consuming process may be treated prior to passage through the CO2 to CO conversion system. In one embodiment the CO2 to CO conversion system is a rWGS unit, which can be single stage or two or more stages.
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, CO2, H2, 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.
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.
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.
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.
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.
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).
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.”
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.
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.
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.
“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, CO2, and/or H2 to acetyl-CoA.
An “anaerobe” is a microorganism that does not require O2 for growth. An anaerobe may react negatively or even die if O2 is present above a certain threshold. However, some anaerobes can tolerate low levels of O2 (i.e., 0.000001-5% O2). Typically, a microorganism of the disclosure is an anaerobe.
“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 CO2, (2) terminal electron-accepting, energy conserving process, (3) mechanism for the fixation (assimilation) of CO2 in the synthesis of cell carbon (Drake, Acetogenic Prokaryotes, In: The Prokaryotes, 3rd 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.
An “ethanologen” is a microorganism that produces or is capable of producing ethanol. Typically, a microorganism of the disclosure is an ethanologen.
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 CO2. Typically, a microorganism of the disclosure is an autotroph.
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.
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.
Table 1 provides a representative list of microorganisms and identifies their functional characteristics.
Acetobacterium woodii
Alkalibaculum bacchii
Blautia producta
Butyribacterium methylotrophicum
Clostridium aceticum
Clostridium autoethanogenum
Clostridium carboxidivorans
Clostridium coskatii
Clostridium drakei
Clostridium formicoaceticum
Clostridium ljungdahlii
Clostridium magnum
Clostridium ragsdalei
Clostridium scatologenes
Eubacterium limosum
Moorella thermautotrophica
Moorella thermoacetica (formerly
− 3
Clostridium thermoaceticum)
Oxobacter pfennigii
Sporomusa ovata
Sporomusa silvacetica
Sporomusa sphaeroides
Thermoanaerobacter kivui
1
Acetobacterium woodii can produce ethanol from fructose, but not from gas.
2 It has not been investigated whether Clostridium magnum can grow on CO.
3 One strain of Moorella thermoacetica, Moorella sp. HUC22-1, has been reported to produce ethanol from gas.
4 It has not been investigated whether Sporomusa ovata can grow on CO.
5 It has not been investigated whether Sporomusa silvacetica can grow on CO.
6 It has not been investigated whether Sporomusa sphaeroides can grow on CO.
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.
“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%.
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.
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.
The CO-consuming process 140 of
In some embodiments, the CO-consuming process 140 of
In particular embodiments, at least one constituent removed by the removal module 150 of
The O2 by-product of water electrolysis processes employed, for example when the CO2 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 CO2 to CO conversion system, O2 could be generated as a by-product and may be separated and passed through optional conduit 136 in of
Typically, the industrial processes described herein derive the required O2 by air separation. Production of O2 by air separation is an energy intensive process which involves cryogenically separating O2 from N2 to achieve the highest purity. Production of O2 by CO2 conversion to CO as in line 136, depending upon the CO2 to CO conversion system selected, and/or water electrolysis as in line 166, and displacing O2 produced by air separation, could offset up to 5% of the electricity costs in an industrial process.
Several C1-generating industrial processes involving partial oxidation reactions require an O2 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, O2 from the CO2 to CO conversion system and/or O2 from water electrolysis may be used to off-set or completely replace the O2 typically supplied through air separation.
As shown in
In particular embodiments where the CO2 to CO conversion system generates O2 by-product, the process includes an O2 separation module 260 following the CO2 to CO conversion system 230 to separate at least a portion of O2 from the gas generated in CO2 to CO conversion system 230. In embodiments utilizing an O2 separation module 260 downstream of CO2 to CO conversion system 230, at least a portion of gas stream 234 is fed from the CO2 to CO conversion system 230 to O2 separation module 260. In embodiments incorporating O2 separation module 260, an O2-enriched stream 264 may be passed industrial process 210 thereby displacing the need for other sources of O2 in industrial process 210. In embodiments utilizing O2 separation module 260 downstream of CO2 to CO conversion system 230, at least a portion of the O2-lean stream 262 is passed from O2 separation module 260 to the CO-consuming process 240. In some embodiments utilizing an O2 separation module 260 downstream of CO2 to CO conversion system 230, at least a portion of the O2-lean stream 262 is passed from O2 separation module 260 back to the CO2 to CO conversion system 230 in line 266. In embodiments not utilizing an O2 separation module 260, a portion of the gas stream 236 may be passed from the CO2 to CO conversion system 230 to the industrial process 210.
In some embodiments, the CO-consuming process 240 of
The CO-consuming process 240 of
Providing a high purity CO2 stream, a CO2-rich stream, to a CO2 to CO conversion system, such as a rWGS unit, increases the carbon capture efficiency of a CO-consuming process. To increase the concentration of CO2 in a stream, one or more CO2 concentration module may be incorporated in the process. The CO-enriched stream generated by the CO2 to CO conversion system, such as a rWGS unit, stream may have a concentration of CO between 20-90%.
At least a portion of the gas stream 336 from the CO2 to CO conversion system 330 may be passed to the industrial process 310. In particular embodiments, the process includes an O2 separation module 360 following the CO2 to CO conversion system 330, where the gas stream 334 is passed from the CO2 to CO conversion system 330 to the O2 separation module 360 to separate at least a portion of O2 from the gas stream 334. In embodiments utilizing O2 separation module 360 after the CO2 to CO conversion system 330, at least a portion of the O2-enriched stream 364 is passed from O2 separation module 360 to industrial process 310. In embodiments utilizing an O2 separation module 360 after the CO2 to CO conversion system 330, at least a portion of the O2-lean stream 362 is passed from O2 separation module 360 to CO-consuming process 340. In some embodiments utilizing an O2 separation module 360 after the CO2 to CO conversion system 330, at least a portion of the O2-lean stream 366 is passed from the O2 separation module 260 back to CO2 to CO conversion system 330. In embodiments not utilizing an O2 separation module 360, a portion of the gas stream 336 may be passed from the CO2 to CO conversion system 330 to industrial process 310.
Concentrating the CO2 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.
In some embodiments, the CO-consuming process 340 of
The CO-consuming process 340 of
In particular embodiments, a CO2 concentration module may be placed after a removal module.
At least a portion of the gas stream 436 from the CO2 to CO conversion system 430 may be passed to the industrial process 410. In particular embodiments, the process includes O2 separation module 460 following the CO2 to CO conversion system 430 to separate at least a portion of O2 from the gas stream 434. In embodiments utilizing an O2 separation module 460 after the CO2 to CO conversion system 430, at least a portion of the gas stream 464 is fed from the O2 separation module 460 to the industrial process 410. In embodiments utilizing O2 separation module 460 after the CO2 to CO conversion system 430, at least a portion of the O2-lean stream 462 is passed from O2 separation module 460 to CO-consuming process 440. In some embodiments utilizing O2 separation module 460 after CO2 to CO conversion system 430, at least a portion of the O2-lean stream 466 is passed from the O2 separation module 460 back to the CO2 to CO conversion system 430. In embodiments not utilizing O2 separation module 460, a portion of the gas stream 436 may be passed from the CO2 to CO conversion system 430 to the industrial process 410, particularly if the selected CO2 to CO conversion system 430 generates O2.
In some embodiments, the CO-consuming process 440 of
The CO-consuming process 440 of
In particular embodiments, the disclosure provides one or more pressure modules 580 to increase the pressure of the converted gas 532 from the CO2 to CO conversion system 530. In embodiments utilizing a pressure module 580 after the CO2 to CO conversion system 530, at least a portion of the gas stream 532 is passed from CO2 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.
In various embodiments, water electrolysis module 1500 is incorporated along with the O2 separation module 560 and/or the pressure module 580. In various embodiments, a water substrate 1506 is introduced to water electrolysis module 1500, and H2-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, H2-rich gas stream 1504 is passed directly from water electrolysis module 1500 to CO-consuming process 540. Depending upon the CO2 to CO conversion system selected, such as a rWGS unit which uses H2 as a reactant, an H2-enriched stream 1510 may be passed from water electrolysis module 1500 to CO2 to CO conversion system 530. Optionally, at least a portion of O2-enriched stream 1508 generated by water electrolysis module 1500 may be passed to industrial process 510.
In certain embodiments, the disclosure integrates an industrial process 510, an optional CO2 concentration module 570, a removal module 520, a CO2 to CO conversion system 530, an optional O2 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. CO2-comprising gas 514 from the industrial process 510 is passed to an optional CO2 concentration module 570 to increase the concentration of the CO2 in the gas stream 514 and remove one or more constituent 574. A first CO2 concentrated stream 572 from first CO2 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 CO2 concentration module 570 to increase the concentration of the CO2 in the gas stream 524 and remove one or more constituent 574. A second CO2 concentrated stream 572 is passed to a CO2 to CO conversion system 530 for conversion of at least a portion of the second CO2 concentrated stream 572. At least a portion of the converted gas stream 534 may be passed to an optional O2 separation module 560 to separate at least a portion of O2 from the converted gas stream 534. At least a portion of the O2-rich gas stream 564 may be passed from the optional O2 separation module 560 to the industrial process 510. At least a portion of the O2-rich gas stream may be fed from the CO2 to CO conversion system 530 to the industrial process 510 via a conduit 536, if the selected CO2 to CO conversion system 530 generates O2. At least a portion of the O2-depleted gas stream 562 may be passed from the optional O2 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 H2-rich gas stream 1502 prior to being introduced to the CO-consuming process 540.
The CO-consuming process 540 of
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.
In various instances, the conversion of a CO2-comprising gaseous substrate by an CO2 to CO conversion system results in one or more constituent passing through the CO2 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 O2. In various embodiments, the further removal module is a deoxygenation module for removing O2 from the CO-enriched stream.
In certain embodiments, the disclosure integrates an industrial process 610, an optional CO2 concentration module 670, a removal module 620, a CO2 to CO conversion system 630, a further removal module 690, an optional O2 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 CO2 concentration module 670 between the industrial process 610 and the removal module 620, the CO2-comprising gas 612 from the industrial process 610 is passed to the removal module 620. In embodiments including an optional CO2 concentration module 670 between the industrial process 610 and the removal module 620, the CO2-comprising gas 614 from the industrial process 610 is passed to an optional CO2 concentration module 670 to increase the concentration of the CO2 in the gas stream 614 and remove one or more constituent 674. The gas stream having increased CO2 concentration 672 from optional CO2 concentration module 670 is passed to removal module 620, to remove and/or convert one or more constituents 628. In embodiments not including a CO2 concentration module 670 between the removal module 620 and the CO2 to CO conversion system 630, the treated stream 622 is passed from removal module 620 to CO2 to CO conversion system 630. In embodiments including a CO2 concentration module 670 between the removal module 620 and the CO2 to CO conversion system 630, the treated stream 624 is then passed to an optional CO2 concentration module 670 to increase the concentration of the CO2 in the treated stream 624 and remove one or more constituents 674. The resulting CO2 enriched stream 672 is passed from optional CO2 concentration module 670 to CO2 to CO conversion system 630 for conversion of at least a portion of CO2 enriched stream 672.
Depending upon the CO2 to CO conversion system 630 selected, O2 may be generated, and if so, at least a portion of a O2-rich gas stream 636 may be passed from the CO2 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 O2 separation module 660 to separate at least a portion of O2 from treated gas stream 634. At least a portion of the O2-enriched gas stream 664 may be passed from the optional O2 separation module 660 to the industrial process 610. At least a portion of the O2-depleted gas stream 662 may be passed from the optional O2 separation module 660 to the further removal module 690 to remove and/or convert one or more constituents 698.
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 H2-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 H2-rich gas stream 1602 discussed above, and/or H2-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, O2 produced by the water electrolysis module 1600 may be passed in O2 stream 1608 to the industrial process 610.
The CO-consuming process 640 of
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.
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.
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.
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.
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.
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.
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.
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.
This application claims the benefit of U.S. Provisional Patent Application No. 63/173,247, filed Apr. 9, 2021, the entirety of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63173247 | Apr 2021 | US |
