Patent Application
20220177399
The present application claims the benefit from the priority of European Patent Application No. 20206713, entitled “SYSTEMS AND METHODS FOR GENERATING A FORMIC ACID PRECURSOR FROM A CO2 GAS STREAM,” filed Nov. 10, 2020, and is hereby incorporated by reference in its entirety.
The present disclosure relates, in some embodiments, to systems and methods that convert CO2 (e.g., from a CO2 stream produced by an oil and gas industry asset) into a viable commercial product. In particular, the system and methods convert CO2 into formic acid precursors (e.g., HCOOK, HCOONa) and/or formic acid (HCOOH).
A large portion of the energy used by consumers is derived from the processing and combustion of fossil fuels (e.g., hydrocarbon fuels). However, besides generating energy, these combustion processes may also generate undesirable greenhouse gases (e.g., carbon dioxide (CO2)).
Two main strategies are used in controlling anthropogenic emissions of greenhouse gases. The first strategy is to simply find ways to reduce the overall fossil fuel consumption through energy use limitation or use of alternative energy methods (e.g., solar, wind, electric).
However, this strategy does not mitigate the formation of the greenhouse gases. The second strategy includes abatement of generated greenhouse gases, for example, through their transformation into environmentally benign or even beneficial products. Greenhouse gas abatement technology allows for fossil fuel consumption without decreasing or restricting fossil fuel consumption.
Carbon dioxide (CO2) is the primary gas in greenhouse gases. There are currently technologies that capture and store CO2 (e.g., as it is generated from fossil fuel processing or combustion system). However, these technologies are limited to CO2 gas abatement without providing additional commercial and/or environmental benefits.
In a first embodiment, a method for generating a carboxylic acid from carbon dioxide (CO2), the method includes (a) feeding a gas stream having the CO2 to a first reactor having a base (MOH) to produce bicarbonate (MHCO3) and (b) feeding the MHCO3 generated in the first reactor to a second reactor disposed downstream from the first reactor. The second reactor includes a catalyst. The method also includes (c) contacting the MHCO3 with hydrogen gas in the presence of the catalyst in the second reactor to produce formate (HCOOM) and (d) electrolysing an aqueous solution of a metal halide (MCl) in a chloro-alkali electrolysis reactor fluidly coupled to the first reactor, the second reactor, or both to produce at least a portion of the MOH, the hydrogen gas and Cl2. The portion of the MOH is used in step (a) and the carboxylic acid is formic acid (HCOOH).
In a second embodiment, a system for generating a carboxylic acid from carbon dioxide (CO2) includes a first reactor fluidly coupled to a gas source having the CO2 and that may combine the CO2 with a base (MOH) to generate bicarbonate (MHCO3) and, optionally, an off gas and a second reactor disposed downstream from and fluidly coupled to the first reactor and having a catalyst. The second reactor may receive the bicarbonate and hydrogen gas and produce formate (HCOOM), and a temperature and hydrogen pressure within the second reactor is in the range of from 15° C. to 210° C. and from 0.001 bara to 100 bara, respectively. The system also includes a chloro-alkali electrolysis reactor disposed downstream from and fluidly coupled to the first reactor and the second reactor. The chloro-alkali electrolysis reactor may produce at least a portion of the base, a hydrogen gas and chlorine (Cl2), and to provide at least a portion of the base to the first reactor.
In a third embodiment, a method for generating a carboxylic acid from carbon dioxide (CO2) includes (a) mixing a gas stream having the CO2 with a base (MOH) to produce bicarbonate (MHCO3), (b) contacting the MHCO3 with hydrogen gas in the presence of the catalyst to produce formate (HCOOM), and (d) electrolysing an aqueous solution of a metal halide (MCl) to produce at least a portion of the MOH used in step (a). The carboxylic acid is formic acid (HCOOH).
Some embodiments of the disclosure may be understood by referring, in part, to the present disclosure and the accompanying drawings, in which:
One or more specific embodiments of the present disclosure will be described below. These described embodiments are examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these embodiments, not all features of an actual implementation may be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions will be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.
The terms “approximately,” “about,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of a stated amount.
Existing techniques for CO2 gas abatement do not convert CO2 into commercially viable products nor provide an environmental benefit. Accordingly, there is a need for improved methods and systems for CO2 gas abatement which also provide commercial and/or environmental benefits. The present disclosure describes methods and systems for transforming a CO2 gas stream (e.g., derived from fossil fuel processing or combustion system) into formic acid (HCOOH), a multi-functional base chemical (e.g., a preservative and an antibacterial agent in livestock feed, a fuel for electric cars having formic acid fuel cells, a hydrogen storage material for hydrogen fuel cells, an additive for various cleaning products, an intermediary to produce isobutanol from CO2 using microbes, a de-icer) and its precursors.
Disclosed herein are systems and methods for generating a formic acid precursor (HCOOM) and/or a formic acid (HCOOH) from a carbon dioxide (CO2) gas stream. The disclosed system and method advantageously convert CO2 into formic acid, a multi-functional base chemical that may be readily commercialized and precursors thereof (e.g., HCOOK, HCOONa). Formic acid may desirably be used, for example, as a preservative and an antibacterial agent in livestock feed, a fuel for electric cars having formic acid fuel cells and indirectly in hydrogen fuel cells as a hydrogen storage material, an additive for various cleaning products, an intermediary to produce isobutanol from CO2 using microbes, a de-icer, and many other uses. Additionally, as disclosed herein, the system and method may directly convert diluted CO2 streams into formic acid in a scalable and less complex manner in comparison to existing chemical synthetic technologies that may produce undesirable waste products. Additionally, many of the method steps and system components disclosed herein involve catalytic cycles that recycle by-products from other methods steps and system components, thereby minimizing waste-products.
In particular, the embodiments disclosed herein provide a first process step (a) in which a gas stream having CO2 is mixed with base (MOH) such that the CO2 in the gas stream reacts with the alcohol to produce MHCO3 and a second process step (b) that includes combining the MHCO3 produced in step (a) with hydrogen gas (H2) in the presence of a catalyst to produce HCOOM. Additional embodiments include electrolysing an aqueous solution of MCl in, for example, a chloro-alkali electrolysis process to produce at least a MOH, hydrogen gas and a chlorine (Cl2), and using the MOH produced from the electrolysis process in step (a). Therefore, the CO2 contained in the gas stream may be combined with the MOH under certain reactor conditions to form a formic acid precursor HCOOM. The disclosed process includes an intermediate process step that generates an intermediate MHCO3 from the CO2 and MOH and converts the MHCO3 into the formic acid precursor HCOOM.
With the foregoing in mind,
In the illustrated embodiment, the hydrogenation reactor 115 is also connected and fluidly coupled to the chloro-alkali electrolysis reactor 120 through a first hydrogen (H2) gas line, a water electrolysis reactor 125 through a second H2 gas line, and an ion exchange resin reactor 130 through a formate (HCOOM) transfer line. In certain embodiments, the hydrogenation reactor 115 feeds formate to a reactor disposed between the hydrogenation reactor 115 and the ion exchange resin reactor 130. The reactor (e.g., a furnace) may convert the formate into oxalate (MOOC-COOM), which is converted to oxalic acid in the ion exchange resin reactor 130. For example, the formate may be heated in the reactor to a temperature between about 250° C. to 500° C. to deprotonate the formate, thereby forming oxalate and H2.
As discussed above, the system 100 includes the ion exchange resin reactor 130 positioned downstream of and fluidly coupled to the hydrogenation reactor 115. The ion exchange resin reactor 130 is connected and fluidly coupled to a formate (HCOOH) tank 135 through a formic acid (HCOOH) transfer line, to a converter 140 through a hydrochloric acid (HCl) transfer line, and to the chloro-alkali electrolysis reactor 120 through a metal halide (MCl) transfer line. The ion exchange resin reactor 130 may include a protonated ion exchange resin. In operation, the ion exchange resin reactor 130 protonates the formate to generate formic acid (HCOOH) and, optionally, the metal halide (e.g., sodium chloride (NaCl) and/or potassium chloride (KCl)).
The metal halide transfer line may provide KCl, NaCl, or both to the chloro-alkali electrolysis reactor 120. Optionally, in certain embodiments, the MCl transfer line feeds a metal halide solution, such as KCl or NaCl, obtained from the ion exchange resin reactor 130 and feeds the MCl solution to a salt purifier. The salt purifier generates a purified salt that is provided to the chloro-alkali electrolysis reactor 120. The purified MCl generated in the salt purifier may be in solution.
In some embodiments, the MCl solution may be generated by an esterification rector instead of the ion exchange resin reactor 130. For example,
The system 200 also includes a hydrolysis and distillation reactor 250 disposed downstream from and fluidly coupled to the esterification reactor and upstream from and fluidly coupled to the HCOOH tank 135 through the HCOOH transfer line, and to the CH3OH/HCO2CH3 reactor 255 reactor through the CH3OH/HCO2CH3 transfer line. In operation, the hydrolysis and distillation reactor 250 receives the ester from the esterification reactor 245 and protonates the ester, in a second protonation step, to generate the formic acid.
Returning to
As shown in
Typical liquid space velocities inside a fixed bed reactor are 0.1-5 volume feed/(volume catalyst*hour) (v/(vh)). Alternatively, a stirred tank reactor with suspended catalyst may be used, preferably with a catalyst concentration in the range of 0.01 g/L to 100 g/L.
In
Once the HCOOM is produced in the hydrogenation reactor 115, it may be transferred to the ion exchange resin reactor 130 through the HCOOM transfer line and converted to HCOOH (i.e., formic acid). The ion exchange resin reactor 130 includes an ion exchange resin. The ion exchange resin includes a polymer that acts as a medium for ion exchange. The ion exchange resin may be a cation-exchange resin such as, for example, Dowex 50WX8 or any other suitable cation-exchange resin. The ion exchange resin may be strongly acidic or weakly acidic.
Following formation of the formic acid in the ion exchange resin reactor 130, it may be fed to the HCOOH tank 135 through the HCOOH transfer line for storage and/or distribution. The HCOOH tank 135 may be any suitable shape and size for containing the formic acid produced by the system 100, 200 and made of any material (e.g., a plastic, a glass, a metal) suitable for storing formic acid without affecting the integrity of the material. The HCOOH tank 135 may also include an apparatus for transferring the formic acid to another location. For example, the HCOOH tank 135 may connected to and fluidly coupled to a pipeline that directs the formic acid to a desired location. The HCOOH tank 135 may also be removably coupled (e.g., via a pipe or conduit) to a container on a vehicle (e.g., a transfer truck) used to transfer the formic acid to another location.
As discussed above, the system 100 includes the water electrolysis reactor 125 that is fluidly coupled to the hydrogenation reactor 115 through the second H2 transfer line. The water electrolysis reactor 125 may split water into oxygen (O2) and H2 and transfer the H2 to the hydrogenation reactor 115. The water electrolysis reactor 125 may include one or more electrodes, a container, a water input line, and an oxygen gas outlet. In operation, the water electrolysis reactor 125 may generate from about 1% to about 100% of the H2 used by the hydrogenation reactor 115. For example, the water electrolysis reactor 125 may generate from about 1%, about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, or about 100% of the H2 used by the hydrogenation reactor 115, where about includes plus or minus 5%.
In addition to receiving H2 from the water electrolysis reactor 125, the hydrogenation reactor 115 may receive H2 from the chloro-alkali electrolysis reactor 120, as shown in
As discussed above, the system 100 also includes the converter 140, which is connected and fluidly coupled to the chloro-alkali electrolysis reactor 120 via a chlorine (Cl2) transfer line through which it may receive Cl2 generated by the chloro-alkali electrolysis reactor 120. The converter 140 may mix or otherwise combine the Cl2 with water to form HCl. In this step, the Cl2 may be mixed with water and contacted with a bed of carbon to generate an HCl containing stream which may be fed to the ion exchange resin reactor 130 through the HCl transfer line. In certain embodiments, at least 1 to 100 vol. % of the H2 and Cl2 generated in the chloro-alkali electrolysis reactor 120 may be combined with water in the convertor 140. For example, between from 1 to 99 vo. %, preferably between from 90 to 100 vol. %, of the H2 and Cl2 are combined with water in the convertor 140 to generate HCl. In one embodiment, between from 75 to 90 vol. % of the Cl2 from the chloro-alkali electrolysis reactor 120 is combined with the water in the convertor 140. In other embodiments, at least a portion of the H2 combined with the water in the convertor 140 is provided by the water electrolysis reactor 125. For example, between from 1 to 99 vol. %, preferably 1 to 50 vol. %, 1 to 15 vol. %, or 1 to 15 vol. % of the H2 from the water electrolysis reactor 125 is provided to the convertor 140. In certain embodiment, 100 vol % of the H2 combined with the water in the convertor 140 is from the water electrolysis reactor 125. That is, in this particular embodiment, substantially no H2 from the chloro-alkali electrolysis reactor 120 is provided to the convertor 140 and mixed with the water. The convertor 140 may be a catalytic convertor, a thermal convertor, or any other suitable system that converts H2 and Cl2 into HCl. At least a portion of the HCl generated in the convertor 140 may be used for protonating the formate to produce the carboxylic acid (e.g., formic acid, acetic acid, and/or oxalic acid) in the ion exchange resin reactor 130, the esterification reactor 245 (
As discussed above, with reference to
Embodiments of the present disclosure also include a method for generating formic acid from a CO2 gas stream. An exemplary pathway for generating formic acid (HCOOH) in accordance with the present disclosure includes the stoichiometry shown below:
The disclosed method includes using t bubble column reactor (e.g., the bubble column reactor 110) to convert CO2 in the CO2 gas stream into a bicarbonate compound (MHCO3) such as, for example, KHCO3 and/or NaHCO3 depending on the base used, and a hydrogenation reactor (e.g., the hydrogenation reactor 115) to convert the MHCO3 to the respective metal formate (HCOOM, where M is either K or Na), an esterification reactor (e.g., the esterification reactor 245) to convert the HCOOM to methyl format (HCO2CH3), and a hydrolysis and distillation reactor (e.g., the hydrolysis and distillation reactor 250) to convert the HCO2CH3 to formic acid.
Preferably, the stoichiometry of the pathway for generating formic acid via the hydrolysis and distillation reactor is shown below:
Alternatively, in accordance with an embodiment of the disclosed method, the metal formate (HCOOM, where M is Na or K) may be combined with HCl (e.g., HCl gas stream or aqueous HCl) in a distillation reactor to form formic acid according to the stoichiometry pathway shown below:
As discussed above, the method presented herein may include passing a CO2 gas stream having CO2 through a reactor (e.g., the bubble column reactor 110) having a base (e.g., MOH where M is Na or K) to produce the MHCO3 and an off gas. According to some embodiments, the CO2 gas may be converted to MHCO3 in a separated unit outside of system (e.g., the system 100, 200, 300) instead of in the bubble column reactor. In this particular embodiment, the MHCO3 is generated in a remote location and transferred to the system, for example, via a transfer vehicle. The CO2 gas stream may be from about 0.01 vol % CO2 to about 100 vol % CO2 (vol % relative to the total gas stream volume). The disclosed method may include a step of combining the MHCO3 produced by the bubble column reactor with hydrogen gas at a temperature up to 210° C. in the hydrogenation reactor to form HCOOM, where M is Na or K. For example, the temperature may range from about 12.5° C. to about 210° C., from about 15° C. to about 200° C., from about 15 to about 150° C., from about 15° C. to about 75° C. In certain embodiments, the hydrogen gas may be at a temperature of about 15° C., about 20° C., about 25° C., about 30° C., about 35° C., about 40° C., about 45° C., about 50° C., about 55° C., about 60° C., about 65° C., about 70° C., or about 75° C., where about includes plus or minus 2.5° C.
In other embodiments, the method includes a step of combining the MHCO3 (e.g., KHCO3 and/or NaHCO3) produced by the bubble column reactor with a catalyst and hydrogen gas in the hydrogenation reactor (e.g., the hydrogenation reactor 115) to produce formate (HCOOM) at a temperature ranging from 15° C. to 210° C. and a hydrogen pressure ranging from about 0.001 bara to about 100 bara for 6 to 24 h. The hydrogen pressure may be about 0.001 bara, about 0.005 bara, about 0.01 bara, about 0.05 bara, about 0.1 bara, about 0.5 bara, or about 1.0 bara, where about includes plus or minus 0.0025 bara in between 0.001 bara and 0.01 bara, plus or minus 0.025 in between 0.01 and 0.1 bara, and plus or minus 0.25 in between 0.1 bara and 1.0 bara. The hydrogen pressure may be about 1.0 bara, about 10 bara, about 20 bara, about 30 bara, about 40 bara, about 50 bara, about 60 bara, about 70 bara, about 80 bara, about 90 bara, or about 100 bara, where about includes plus or minus 5 bara.
The hydrogenation reactor may be a fixed bed reactor having liquid space velocities in the range of from about 0.1 to 5 h−1. For example, the hydrogenation reactor may be a trickle-bed or liquid phase reactor. In certain embodiments, the hydrogenation reactor may be a tank reactor having a suspended catalyst. In one embodiment, the hydrogenation reactor may be a loop reactor and include one or more catalysts. By way of non-limiting example, the catalyst in the hydrogenation reactor includes a copper catalyst, a palladium catalyst, a nickel catalyst, and combinations thereof. Catalysts containing copper or nickel may be in the form of a wire, powder, shavings, granules, and combinations thereof of respective metal. The catalyst may be in an amount of from about 0.001 to 70.0 wt. % in relation to the carrier material. For example, the catalyst may be in an amount of from 0.01 to 40.0 wt. %, 10.0 to 70.0 wt. %, 10.0 to 40.0 wt. %, 0.1 to 5.0 wt. %, 0.01 wt. %, 5.0 wt. %, 10.0 wt. %, 40.0 wt. %, or 70.0 wt. % each in relation to the carrier material. The palladium catalyst may include Pd/Al2O3, 0.1-5 wt. % (based on carrier material) Pd on carbon or theta alumina or titania; 10-70 wt. % (based on carrier material) Ni/SiO2 or Ni/ASA (amorphous silica alumina)—precipitated; and 10-40 wt. % (based on carrier material) Ni/theta alumina—impregnated, and combinations thereof. In certain embodiments, the catalyst is a copper catalyst. For example, the copper catalyst may be a copper wire, copper powder, copper shavings, copper granules, and combinations thereof. The copper catalyst may or may not be supported on a carrier. When using the copper catalyst, Cu2+ ions may be produced after at least 100 h. For example, after at least between 5 to 100 h, 5 to 50 h, or 5 to 20 h. In particular, the Cu2+ ions are produced after at least 10 h or 5 h. In embodiments in which the catalyst is Pd/C, the catalyst may be activated prior to use at a temperature of 30 to 110° C. and a hydrogen flow rate of 60 L/h
The catalyst may be used at a concentration ranging from about 0.01 mmol to about 1 mmol. In certain embodiments, the catalyst may be at a concentration in a range of from 0.01 g/L to 100 g/L, preferably 0.1 g/L to 50 g/L, preferably 1 g/L to 30 g/L. In certain embodiments, the catalyst may be at a molar amount ranging from about 0.01 mmol to about 1 mmol, preferably 0.1 mmol to about 1 mmol, preferably 0.5 mmol to about 1 mmol. As should be appreciated, the catalyst may be recycled for one or more cycles during operation of the system (e.g., the system 100, 200, 300). Accordingly, in certain embodiments, the method disclosed herein includes recycling the catalyst for at least 1 to 15 cycles, preferably 1 to 12 cycles, 1 to 10 cycles, or 1 to 5 cycles. For example, the catalyst may be recycled for at least 2 cycles, 5 cycles, 10 cycles, 12 cycles, or 15 cycles with a conversion of bicarbonate to formate of at least 50 to 99%, 70 to 99%, 80 to 99%, 85 to 95%, 90 to 95%, 95% in every cycle
In certain embodiment, the method disclosed herein includes a cleaning step after the hydrogenation of bicarbonate to formate. For example, the cleaning step may remove at least divalent ions (e.g., Cu2+) produced in the hydrogenation reactor. In particular, the cleaning step is performed when using a copper catalyst in the hydrogenation reactor to convert the bicarbonate into formate.
The disclosed method may also include a step of passing the formate (HCOOM, where M is Na or K) produced by the hydrogenation reactor through an ion exchange resin reactor (e.g., the ion exchange resin reactor 130) to produce formic acid. The ion exchange resin reactor may form the formic acid from the HCOOM starting material in a yield ranging from about 1% to about 75% based on a molar amount of the formate. For example, the ion exchange resin reactor may form the formic acid in a yield of about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, or about 50%, where about includes plus or minus 2.5%, based on the amount starting material coming from the HCOOM.
In addition to forming formic acid by protonating formate, the ion exchange resin reactor also removes divalent ions (e.g., Cu2+) that may be present in the formate feed from the hydrogenation reactor. Therefore, in certain embodiments, the ion exchange resin reactor may also be used to perform the cleaning step discussed above. However, as should be appreciated, the cleaning step may be performed upstream of the ion exchange resin reactor using other cleaning techniques suitable for removing divalent ions.
The method also includes a step of capturing the formic acid formed by the ion exchange resin reactor in a HCOOH tank (e.g., the HCOOH tank 135). In some embodiments, the CO2 may be used for back protonation of the ion exchange resin contained within the ion exchange reactor to regenerate the ion exchange resin.
The method further includes a step of producing at least a portion of a hydrogen gas used by the hydrogenation reactor, the Cl2, and the base (MOH, where M is Na or K) by electrolysis of water in a chlorine-alkali electrolysis reactor (e.g., the chlorine-alkali electrolysis reactor 120). The chlorine-alkali electrolysis reactor may generate from about 1% to about 100% of the H2 used by the hydrogenation reactor. For example, the chlorine-alkali electrolysis reactor may generate about 1%, about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, or about 100% of the H2 used by the hydrogenation reactor, where about includes plus or minus 5%. In some embodiments, the method includes a step of transferring the MOH produced by the chlorine-alkali electrolysis reactor to the bubble column reactor through a MOH transfer line. Additionally, the method may include transferring the Cl2 generated by the chlorine-alkali electrolysis reactor to the catalytic converter through the Cl2 transfer line so that it may be combined with water to form HCl.
The method also includes a step of producing at least a portion of the hydrogen gas used by the hydrogenation reactor via electrolysis of water in a water electrolysis reactor (e.g., the water electrolysis reactor 125). The water electrolysis reactor may generate from about 1% to about 100% of the H2 used by the hydrogenation reactor. For example, the water electrolysis reactor may generate about 1%, about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, or about 100% of the H2 used by the hydrogenation reactor, where about includes plus or minus 5%.
According to some embodiments, the method may include a step of combining the formate (HCOOM) produced by the hydrogenation reactor with HCl in an esterification reactor (e.g., the esterification reactor 245) to produce a metal chloride (e.g., MCl, where M is Na or K) and methyl formate (HCO2CH3). For example, while in the esterification reactor, the formate undergoes a first protonation in the presence of a solvent such as, for example, water, and HCl (e.g., HCl from the chloro-alkali electrolysis reactor 120, the convertor 140, or both). The HCl may be used to adjust a pH within the esterification reactor. For example, the HCl may adjust the pH to a value ranging from 1 to 5, preferably 1 to 4, or 2. The first protonation in the esterification reactor results in an ester (HCO2CH3) that is fed to a hydrolysation reactor and distilled to generate a water-soluble carboxylic acid such as formic acid.
Accordingly, the method may also include a step of hydrolyzing the HCO2CH3 produced by the esterification reactor in a hydrolysis and distillation reactor (e.g., the hydrolysis and distillation reactor 250) to produce formic acid, and a step of capturing the formic acid formed by a hydrolysis and distillation reactor in the HCOOH tank. The hydrolyzing step (e.g., second protonating step) may be done in the presence of a solvent such as water and at a temperature ranging from between about 20 to 105° C., preferably between about 25 to 100° C., and preferably between about 80 to 100° C.
In some embodiments, the esterification of a formate solution may be carried out by adding a suitable HCl solution to achieve at least the stoichiometric amount of the included formate and a suitable excess (of HCl) to adjust acidic conditions. A mono-alcohol (e.g., MeOH/EtOH or any other suitable alcohol) is added and low boiling esters (e.g., having a boiling point less than 300° C.) that may form are removed (and optionally traces of unconverted alcohol and water are removed as well), preferably removal is achieved with heating. The alcohol and traces of unconverted ester may be recycled back to the esterification reactor 245 after distillation
In one embodiment, the method includes feeding the formate from the hydrogenation reactor (e.g., the hydrogenation reactor 115) to a reactor (e.g., the reactor 306) Certain embodiments of the disclosed method include a step of combining Cl2 produced by the chloro-alkali electrolysis reactor with water to produce HCl in the catalytic converter and transferring the HCl generated in the catalytic converter to the ion exchange resin reactor through the HCl transfer line.
The present disclosure also includes embodiments of a method for generating a formic acid precursor having formate (HCOOM, where M is Na or K) from a CO2 gas stream (e.g., the CO2 gas stream 105) using the system of
The method also includes step (c) passing the HCOOM through a protonated ion exchange resin reactor (e.g., the ion exchange resin reactor 130) to produce formic acid. For example, the protonated ion exchange reactor is disposed downstream from and fluidly coupled to the hydrogenation reactor such that the ion exchange resin reactor receives the formate generated in the hydrogenation reactor where the Na and/or K metal is exchanged for the proton (H+) in the ion exchange resin to form formic acid (HCOOH). In addition, when using a copper catalyst, the ion exchange resin reactor may be used to remove divalent ions (e.g., Cu2+) that may form in the hydrogenation reactor. In certain embodiments, the ion exchange resin reactor includes a cation exchange resin. The ion exchange resin may be regenerated by flowing a stream of hydrochloric acid (HCl) provided by a convertor (e.g., the catalytic convertor 140) to release the Na and/or K from the ion exchange resin by ion exchange with H+, thereby forming a metal halide (MCl, where M is Na or K). In certain embodiments the method further includes step (d) electrolyzing an aqueous solution of the metal halide (e.g., potassium chloride (KCl) or sodium chloride (NaCl)) in a chlorine-alkali electrolysis reactor (e.g., the chlorine-alkali electrolysis reactor 120) disposed downstream from and fluidly coupled to the ion exchange resin reactor to produce at least one of: a portion of the hydrogen gas used in step (b), Cl2, and a portion of the MOH used in step (a). The system used to perform the acts of the methods is arranged in a manner such that the chloro-alkali electrolysis reactor provides (i) at least a portion of the generated hydrogen gas to the hydrogenation reactor, (ii) at least a portion of the MOH to the bubble reactor column, and (iii) at least a portion of the generated Cl2 to the catalytic convertor.
In an alternative embodiment, the method does not use an ion exchange resin reactor to generate the formic acid. Rather, the method uses an esterification reactor (e.g., the esterification reactor 245). Accordingly, in this particular embodiment, the method includes steps (e) combining the HCOOM produced by the hydrogenation reactor with HCl in the esterification reactor to produce the metal halide (MCl, where M is Na or K) and an ester (e.g. methyl formate (HCO2CH3) or ethyl formate (HCO2C2H5)), (f) hydrolyzing the ester produced in the esterification reactor in a hydrolysis and distillation reactor (e.g., the hydrolysis and distillation reactor 255) to produce formic acid, and (g) electrolyzing water in the chlorine-alkali electrolysis reactor to produce at least one of: a portion of the hydrogen gas in step (b), Cl2, and at least a portion of the MOH in step (a). In this particular embodiment, the chlorine-alkali electrolysis reactor receives the metal halide (MCl) from the esterification reactor to produce the Cl2 and the MOH. In certain embodiments, the MCl from the esterification reactor is purified in a salt purifier disposed between and fluidly coupled to the esterification reactor and the chlorine-alkali electrolysis reactor.
The following illustrate some specific example embodiments of the present disclosure. As should be appreciated by those of skill in the art, changes to the disclosed embodiments may be made in without departing from the spirit and scope of the application.
Hydrogenation of Bicarbonate
The following two methods (inside an autoclave (a) and a loop reactor (b)) are examples of a process for hydrogenating bicarbonate.
5 g of mm-sized particles of the oxidic catalyst Pd on carbon catalyst are installed inside a rotating cage, which is placed inside a 250 mL autoclave system. The reactor is closed and flushed with nitrogen for 60 min (flow rate=60 L/h at ambient temperature—thereafter hydrogen is added stepwise to the stream replacing the nitrogen completely (hydrogen flow rate=60 L/h). The reactor is heated up to 100° C. (5K/min). That temperature is maintained for 1 h—followed by a cooling step down to the required reaction temperature of 30-80° C. The hydrogen flow is reduced to 10 L/h.
The potassium bicarbonate solution (100 mL, 1-3 M) is put inside the reactor by use of a common HPLC pump. The stirrer starts at 300 rpm and the reactor valves are closed to adjust an overall reactor pressure of up to 30 bara by constant addition of hydrogen via pressure control. Samples are taken frequently by use of a sampling unit, which can be applied without changing the reaction parameters. The created potassium formate is analysed by ion chromatography.
The following conversion rates are detected after 6 and 24 hrs:
Pressure: 30 bara
Conversion: 6 h=97%
After 24 hrs the reaction mixture is removed completely out of the reactor by use of an uptake pipe. Hydrogen supply is adjusted at 10 L/h after the removal of the liquid and the hydrogenation sequence can be repeated as described above.
The catalyst performance decreases over time, for example after the 12th cycle
Pressure: 30 bara
Conversion: 6 h=68%
The catalyst is washed with 2×200 mL water and heated up to 120° C. (5K/min) under nitrogen flow (60 L/h). 1 vol. % oxygen is added for 60 min. The oxygen addition is stopped, and the catalyst is treated with nitrogen for 2 h before 5 vol. % hydrogen is added for 16 hrs.
The catalyst performance can be recovered after 12 cycles, to:
Pressure: 30 bara
Conversion: 6 h=90%
Inside a loop reactor system, the hydrogenation of potassium bicarbonate is carried out at temperatures <80° C. and an overall pressure of 30 bara. A volume of 500 mL mm-sized oxidic Pd/C catalyst (5 wt. % Pd) are place inside a tubular reactor (ID ˜ 2 inch). The button and the head of the reactor are connected with a liquid cycle line. Two pumps are installed to maintain a liquid cycle flow and to add new feed to the system. A second cycle line provides a gas flow from a top space of the reactor to the button position, which is connected to a gas supply to maintain the overall pressure. The gas is added directly inside the liquid reservoir to saturate the water in the liquid reservoir.
On top of the catalyst bed, 200 mL inert mm-sized ceramic or steel spheres are placed to allow mixing of the gas and liquid phase while passing the gas through the catalyst bed, which enter the reactor at the top position of the reactor.
500 g of mm-sized particles of the oxidic catalyst Pd on carbon catalyst are installed inside the tubular reactor. A top bed of the spheres is placed, after which the reactor is closed, and the bed is flushed up-flow with nitrogen for 60 min (flow rate=500 L/h at ambient temperature—thereafter hydrogen is added stepwise to the stream replacing the nitrogen completely (hydrogen flow rate=500 L/h). The reactor was heated up to 100° C. (5K/min). That temperature is maintained for 1 h—followed by a cooling step down to the required reaction temperature of 30-80° C. The hydrogen flow is reduced to 10 L/h.
The potassium bicarbonate solution (1-3 M) is put inside the reactor by use of a common HPLC pump. After reaching a desired volume of 2.5 L of potassium bicarbonate the addition is stopped. The liquid cycle (150 L/h) and, thereafter, the gas cycle (1000 L/h) are put in operation. The addition of hydrogen is started to build up and maintain the overall reaction pressure (30 bara).
Samples are taken frequently by use of a sampling unit, which can be applied without changing the reaction parameters. The created potassium formate is analysed by ion chromatography. The following conversion rates were detected after 6 and 24 hrs:
Pressure: 30 bara
Conversion: 6 h=80%
The ion exchange processes apply to both potassium and sodium. However, to facilitate discussion of this process, reference will only be made to potassium.
a) Treatment of a Potassium Formate—Generation of Formic Acid Solution in Water.
500 mL of 1 M solution of potassium formate are processed (down flow) with a flow rate of 1 mL/min over a protonated strong cationic exchanger (Dowex 50-WX8-Mesh 50-100). The ion exchanger (550 g) is placed inside a chromatographic column with an inner diameter of 30 mm. Samples are taken frequently at the outlet. The formed formic acid and the potassium content are analysed by ion chromatography.
At the described conditions the amount of the formic acid generated at the outlet corresponds to the amount of processed potassium formate minus the potential hold-up of the ion-exchanger bed (˜5% of the added formate). The potassium concentration in the final solution is below the detection limit.
b) Treatment of a Potassium Formate Containing Potassium Bicarbonate Solution—Generation of Formic Acid Solution in Water.
In a first step the carbon dioxide/bicarbonate is removed in a stirred vessel and in a second (no gas formation) step, the formation of formic acid, may be carried out in a chromatographic column. 500 mL of 1 M solution of potassium formate containing 0.15 mol bicarbonate is treated in a stirred vessel with an equimolar amount of ion exchanger to remove the potassium bicarbonate. The potassium is fixed on the ion exchanger and the carbon dioxide is liberated in the gas phase. The ion exchanger is removed by filtration.
After that the solution is pumped with a flow rate of 1 mL/min over a protonated strong cationic exchanger (Mesh 50-100). The cationic exchanger (amount corresponding to the amount of potassium, 470 g) is placed inside a chromatographic column with an inner diameter of 30 mm. Samples are taken frequently at the outlet. The formed formic acid and the potassium content are analysed by ion chromatography.
At the described conditions the amount of the generated formic acid at the outlet corresponds to the amount of processed potassium formate minus the potential hold-up of the ion exchanger bed (˜5% of the added formate). The potassium concentration in the final solution is below the detection limit.
Alternatively, the treatment of potassium formate containing potassium bicarbonate solution, and generation of formic acid solution in water, can be accomplished in a single step. 500 mL of 1 M solution of potassium formate containing 0.15 mol bicarbonate is treated in a stirred vessel with 550 g of ion exchange resin to remove substantially all the potassium. The potassium is fixed on the ion exchange resin and the carbon dioxide is liberated in the gas phase.
The formed formic acid and the potassium content are analysed by ion chromatography.
The ion exchange resin is removed by filtration.
At the described conditions, the amount of the formic acid generated corresponds to the amount of processed potassium formate minus the potential hold-up of the ion exchange resin (˜5% of the added formate). The potassium concentration in the final solution is below the detection limit.
c) Treatment of a Potassium Formate by Use of Weak Cation Exchanger
500 mL of 1 M solution of potassium formate is processed (down flow) with a flow rate of 1 mL/min over a protonated weak cationic exchange resin (Purolite C107E-Mesh 50-100). The ion exchange resin (75 g) is placed inside a chromatographic column with an inner diameter of 30 mm. Samples are taken frequently at the outlet. The formed formic acid and the potassium content are analysed by ion chromatography.
At the described conditions the amount of the formic acid generated at the outlet corresponds to the amount of processed potassium formate minus the potential hold-up of the ion exchanger bed (˜5% of the added formate). The potassium is removed out of the product only in part. For example, approx. 80% of the added potassium is still present in the product, as shown in
Regeneration of the cation exchange resin by hydrochloric acid may be done using any suitable regeneration technique known in the art that removes sodium from and protonates the cation exchange resin. For example, after the described loading processes, the cation exchange resin (loaded with potassium >50% of maximum loading) is re-protonated, i.e. transferred to the protonated form, by use of the following procedure. After the addition of 5 bed volume of deionized water with a flow rate of 10 mL/min, the ion exchange resin bed is treated with 5 bed volumes of 5 wt. % hydrochloric acid (3 mL/min). Finally, the bed is washed again with 5 bed volume of deionized water with a flow rate of 10 mL/min
e) Regeneration of Weak Cation Exchanger by Use of Carbon Dioxide
A potassium loaded ion exchanger (75 g Purolite C107E-Mesh 50-100) is placed in a pressure stable chromatographic column (ID=20 mm). At ambient temperature 10-30 bed volumes of carbon dioxide saturated deionized water are added from the top with flow rate of 2 mL/min at 30 bara. After the described treatment approx. 90% of the sodium are detected inside the eluate phase. The amount of rinsing water (bed volume) depends on the loading and the amount and type of functional groups of the ion exchanger. Complete regeneration is possible with 50 bed volumes.
The regeneration can be carried out at slight overpressure as well as at higher pressure (pCO2=2-50 bara). At higher pressures the regeneration is more effective because the solubility of carbon dioxide is higher.
At room temperature (20° C.), a Cl2 stream (<10 ml/min range) is inserted finely distributed at the bottom position to a chromatographic/bubble column, which is filled with 2 L water. Non-adsorbed Cl2 leaves the column at the top position of the column. After a concentration >1 g CL2/L is achieved inside the liquid phase. The liquid contains solved chlorine, chloride, hypochlorite, and chlorate. (After removing of hypochlorite and/or chlorate) the liquid can be applied to regenerate a cation exchanger according example (see above—“Regeneration of cation exchanger by hydrochloric acid”).
The removal of hypochlorite and/or chlorate should be inserted inside the embodiment of the patent application. Removal can be carried out by chemical reduction and/or adsorption at suitable adsorbents.
At room temperature (20° C.) and ambient pressure (1 bara), a CO2 containing stream of N2 (and O2) is inserted at the bottom position to a chromatographic/bubble column, which is filled with 2 L water and 4.6 mol KOH (2.3 mol KOH/L). The gas stream leaves the column at the top position of the column. A couple of experiments is carried out at overpressure of 1 bara, which was adjusted at the top of the column by a suitable outlet vent and a connected manometer. Gas flow is measured and adjusted in all cases at the inlet line. After 48 hrs of operation the following concentrations are determined inside the solution by TIC (total inorganic carbon) detection.
Thermal processing of a formate/bicarbonate mixtures inside a batch distillation. To generate the ester a solution of 8.2 kg water, 1.69 kg potassium chloride (KCl), 0.88 kg formic acid (HCOOH) is mixed with 1.84 kg of methanol. The mixture is stirred and suitable amount of concentrated HCl (20-30 wt. %) is added to adjust a pH value of ˜2, which can be determined with suitable pH measurement equipment. During the process the in-situ formed ester is distilled off. For example, a distillation unit includes a heating coil upstream from a first distillation column, and a second distillation column fluidly coupled to the first distillation column. Methanol, water, formic acid, a metal halide (MCl) and HCl are feed into the heat exchanger, whereby methyl formate is generated and distilled over a top of the first distillation column. The methyl formate and water is fed to the second distillation column and hydrolysed into the corresponding products (e.g., methanol and formic acid). Therefore 4.8 kg water are filled in the second distillation column at the beginning of each batch. The methanol exits through a top of the second distillation column and may be fed to the heating coil after distillation. The distillation unit is at a pressure of about 1 bara. The distillation columns used include a packed bed, RASCHIG rings, isolated, 25 theoretical plates: ID˜5 cm, Height˜100 cm. A temperature of the heating coil and at a bottom of the second distillation column is >70° C.
At the following mass balance can be determined as depicted in Table 2.
For the present Examples, analysis by ion chromatography the following hardware and conditions were applied:
For the termination of total organic compounds, the following hardware and conditions were applied:
Persons skilled in the art may make various changes in the shape, size, number, separation characteristic, and/or arrangement of parts without departing from the scope of the instant disclosure. Each disclosed component, system, and process step may be performed in association with any other disclosed component, system, or process step and in any order according to some embodiments. Where the verb “may” appears, it is intended to convey an optional and/or permissive condition, but its use is not intended to suggest any lack of operability unless otherwise indicated. Persons skilled in the art may make various changes in methods of preparing and using a composition, device, and/or system of the disclosure. Where desired, some embodiments of the disclosure may be practiced to the exclusion of other embodiments.
Also, where ranges have been provided, the disclosed endpoints may be treated as exact and/or approximations as desired or demanded by the particular embodiment. Where the endpoints are approximate, the degree of flexibility may vary in proportion to the order of magnitude of the range. For example, on one hand, a range endpoint of about 50 in the context of a range of about 5 to about 50 may include 50.5, but not 52.5 or 55 and, on the other hand, a range endpoint of about 50 in the context of a range of about 0.5 to about 50 may include 55, but not 60 or 75. In addition, it may be desirable, in some embodiments, to mix and match range endpoints. Also, in some embodiments, each figure disclosed (e.g., in one or more of the examples, tables, and/or drawings) may form the basis of a range (e.g., depicted value+/−about 10%, depicted value+/−about 50%, depicted value+/−about 100%) and/or a range endpoint. With respect to the former, a value of 50 depicted in an example, table, and/or drawing may form the basis of a range of, for example, about 45 to about 55, about 25 to about 100, and/or about 0 to about 100.
These equivalents and alternatives along with obvious changes and modifications are intended to be included within the scope of the present disclosure. Accordingly, the foregoing disclosure is intended to be illustrative, but not limiting, of the scope of the disclosure as illustrated by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20206713.8 | Nov 2020 | EP | regional |
