WO2024137997A1

WO2024137997A1 - System and method for single-conversion-step electrocatalytic reduction of co2 to ethylene glycol in liquid phase dual membrane electrolyzer

Info

Publication number: WO2024137997A1
Application number: PCT/US2023/085445
Authority: WO
Inventors: Anders B. LAURSEN; Karin U. D. CALVINHO; Richard Porcelli; Antigona MURIQI
Original assignee: Renewco2 Inc.
Priority date: 2022-12-21
Filing date: 2023-12-21
Publication date: 2024-06-27
Also published as: WO2024137997A9

Abstract

A method and system can be configured to integrate a two component electrocatalytic electrode into a working electrolyzer unit, which allows for the conversion of carbon dioxide to an ethylene glycol reaction crude in one reactor. This system increases the process efficiency and utilizes electricity as the energy input for the reaction.

Description

SYSTEM AND METHOD FOR SINGLE-CONVERSION-STEP ELECTROCATALYTIC REDUCTION OF CO2 TO ETHYLENE GLYCOL IN LIQUID PHASE DUAL MEMBRANE ELECTROLYZER

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to U.S. Provisional Patent Application No. 63/476,389 filed December 21, 2022, the entire disclosure of which is hereby incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] This invention was made with government support under DE-SC0020615, and DE- SC0014664 awarded by the U.S. Department of Energy. The government has certain rights in the invention.

FIELD

[0003] The presently disclosed technology relates generally to the electrolytic production of glycol, ethylene glycol, and/or monoethlyene glycol (MEG) from carbon sources, originating from but not limited to oil, gas, coal, or biomass or from captured carbon sources.

BACKGROUND

[0004] Conventional production of ethylene glycol from carbon sources, such as oil, gas, coal, or biomass, includes multiple reaction steps each done at different reaction conditions, such as temperature and pressure. This prior art process can be undesirable because it decreases efficiencies both in terms of energy and conversion efficiencies. These inefficiencies or losses are primarily due to lack of an efficient catalyst that can convert the feedstock (e.g., oil, natural gas, coal, bio-ethanol, and/or bio-mass) in fewer steps, or ideally one step, to achieve the final product. As a result, this prior art production of ethylene glycol from fossil resources, such as oil, gas, or coal, contributes significantly to global carbon dioxide emissions.

[0005] By far the majority, perhaps 90+%, of ethylene glycol is commercially produced in a multi-step process from hydrocarbon feedstocks, via ethylene, then catalytic oxidation of ethylene to ethylene oxide, and finally ethylene oxide hydration to produce ethylene glycol, plus dimers and trimers of the glycol. This is a costly and environmentally challenged process. First, the dominant commercial process for ethylene production, high temperature steam cracking of hydrocarbon feedstocks, is highly energy intensive. In the US, natural gas liquids are a common feedstock, although heavier feeds are also used. For European and Japanese ethylene production, the situation is worse, as heavier feedstocks are still predominant and from these feedstocks, ethylene production is non-selective, requiring energy and capital intensive for separation from many coproducts. Secondly, ethylene oxide production is a costly process that generates a substantial carbon dioxide byproduct. And finally, the hydration of ethylene oxide in an excess of water requires a capital and energy intensive process to recover the desired polymer grade ethylene glycol.

[0006] Current carbon dioxide reduction (CO2RR) suffers from three major constraints: 1) high electricity costs, 2) low relative price of bulk chemicals, and 3) low energy efficiency. Prior art processes are described in U.S. Patent Nos. 10,329,676, 7,972,484, 8,247,098, International Publication No. WO 2012139741 and U.S. Publication No. 2005/0183951.

[0007] Conversion of bio-mass by pyrolysis or fermentation/dehydration to ethylene glycol or ethylene, respectively (the latter is converted to ethylene glycol through the aforementioned process), reduces the process carbon foot-print but still emits large quantities of carbon dioxide. All of the above processes require the combustion of fuels (e.g., bio-fuels or conventional) to provide the energy input of the chemical reactions.

[0008] Known systems for the reduction of carbon dioxide fall into two groups: thermochemical and electrocatalytic. The former has been demonstrated in a multi-step reaction for the production of syn-gas a mixture of carbon monoxide and hydrogen, which is further processed to make compounds such as methanol or long-chain hydrocarbons or waxes (e.g., by the Fisher- Tropsch reaction). The former precursor then has to be converted to either formaldehyde by reoxidation followed by reaction to ethylene glycol by a process commercialized by Eastman Company, or for the latter thermally cracked to ethylene followed by the legacy process conversion to ethylene glycol.

[0009] Liquid phase dual-membrane electrolyzers (LPDM-ECs) are well-known for reduction of water to hydrogen or for reducing carbon dioxide (CO2) to gaseous products such as carbon monoxide, methane, or ethylene, or liquid products such as formate an ethanol (see, e.g., U.S. Patent Nos. 10,648,091 and 11,417,901, as well as European Patent No. 2382174 A2).

[0010] Argonne National Laboratory (ANL) together with the Applicant has developed the first purification steps to remove charged ionic species from an undefined CO2 reduction electrolyzer, such as that disclosed in U.S. Provisional App. No. 63/578,315, which is herein incorporated by reference in its entirety.). [0011] U.S. Patent No. 10,676,833, which is hereby incorporated by reference, discloses a catalyst and co-catalyst in an electrode of given particle sizes, with binders aggregating the catalyst to the electrode support. The electrode in the prior art is described as being utilized with an anode in an undefined electrolyzer. The prior art describes how to obtain a crude solution of hydrocarbons in an aqueous solution mixed with supporting electrolyte, reaction intermediates and homogeneous co-catalyst.

[0012] Further background is provided in the white paper titled, “RenewC02 Catalyst Technology”.

SUMMARY

[0013] In an environmentally aware world, the burdensome, prior art process described above begs replacement with a more selective, direct route.

[0014] One purpose of the presently disclosed technology is to convert a carbon source, such as carbon dioxide, to ethylene glycol in one reactor thereby increasing the process efficiency an action. Electricity can be provided from renewable sources or from a mixture of conventional power production and renewable as is in the grid, or by conventional power production exclusively. Optionally, the process can combine a carbon dioxide reducing catalyst and co- catalyst electrolyzer to obtain a crude reaction product that undergoes a combination of two purification steps.

[0015] In one embodiment, the presently disclosed technology combines a carbon dioxide reducing catalyst and co-catalyst into an electrolyzer to obtain a crude reaction product which is purified in a de-salting unit and Water-removal unit (see, e.g., Fig. 8). The combination of an electrocatalytic electrode with two components both an electrocatalyst and a co-catalyst into one system has not previously been demonstrated in an electrolyzer.

[0016] In one embodiment, in contrast to the prior art, the presently disclosed technology describes incorporating an electrode with two catalysts (e.g., electrocatalyst and co-catalyst) incorporated into a liquid-phase dual membrane electrolyzer cell while combining it with a two- step purification process to obtain mono-ethylene from carbon dioxide (such as that disclosed in PCT Application No. PCT/US23/85275, which is herein incorporated by reference in its entirety). In another embodiment, the presently disclosed technology produces di-ethylene glycol, and in another embodiment the presently disclosed technology produces tri-ethylene glycol, and in another embodiment the presently disclosed technology produces mixtures of ethylene glycol (monomer, dimer, and/or trimer).

[0017] In one embodiment, the presently disclosed technology includes an electrolyzer for the production of ethylene glycol (e.g., monomers, dimers, and/or trimers).

BRIEF DESCRIPTION OF THE DRAWINGS:

[0018] The foregoing summary, as well as the following detailed description of the presently disclosed technology, will be better understood when read in conjunction with the appended drawings, wherein like numerals designate like elements throughout. For the purpose of illustrating the presently disclosed technology, there are shown in the drawing’s various illustrative embodiments. It should be understood, however, that the presently disclosed technology is not limited to the precise arrangements and instrumentalities shown. In the drawings:

[0019] Fig. 1 is a schematic diagram of one embodiment of the presently disclosed technology; [0020] Fig. 2 is a schematic diagram of another embodiment of the electrocatalytic conversion unit of the presently disclosed technology;

[0021] Fig. 3 is a schematic diagram of yet another embodiment of the electrocatalytic conversion unit of the presently disclosed technology;

[0022] Fig. 4 is another schematic diagram of one embodiment of the presently disclosed technology demonstrating where each molecular product is formed;

[0023] Fig. 5 is yet another schematic diagram of one embodiment of the presently disclosed technology demonstrating where each molecular product is formed; and

[0024] Fig. 6 is still another schematic diagram of one embodiment of the entire process of the presently disclosed technology.

[0025] Fig. 7 is another schematic diagram of one embodiment of the process of the electrolytic production module in the presently disclosed technology;

[0026] Fig. 8 is yet another schematic diagram of one embodiment of the process of the desalting unit of the presently disclosed technology;

[0027] Fig. 9 is still another schematic diagram of one embodiment of the evaporation stage of the presently disclosed technology;

[0028] Fig. 10A is an example of the process crude purification as a function of time according to one embodiment of the presently disclosed technology;

[0029] Fig. 10B is another example of the process crude purification as a function of time according to one embodiment of the presently disclosed technology, wherein the drop in conductivity shows the degree of removal of all ionic species as a function of time on stream in the Resin Wafer (RW) Electrodeionization (EDI) (RW-EDI) unit; and

[0030] Fig. 11 is an example of the process crude composition after the first stage evaporator as shown in Fig. 9, wherein this single stage evaporator shows the complete removal of inorganic carbon, the removal of >80% of the methyl glyoxal (MG), the retention of nearly all ethylene glycol (MEG).

DETAILED DESCRIPTION

[0031] While systems, devices and methods are described herein by way of examples and embodiments, those skilled in the art recognize that the presently disclosed technology is not limited to the embodiments or drawings described. Rather, the presently disclosed technology covers all modifications, equivalents and alternatives falling within the spirit and scope of the appended claims. Features of any one embodiment disclosed herein can be omitted or incorporated into another embodiment.

[0032] Any headings used herein are for organizational purposes only and are not meant to limit the scope of the description or the claims. As used herein, the word “may” is used in a permissive sense (i.e., meaning having the potential to) rather than the mandatory sense (i.e., meaning must). Unless specifically set forth herein, the terms “a,” “an” and “the” are not limited to one element but instead should be read as meaning “at least one.” The terminology includes the words noted above, derivatives thereof and words of similar import.

[0033] The phrase “high selectivity” is defined herein as greater than 50%. For example, and without limitation, more than 50% of the electrons from the cathode are directed to the product of interest (e.g., ethylene glycol).

[0034] The prior art, including U.S. Patent No. 10,676,833, does not describe specific strategies for limiting co-catalyst concentration in the reaction solution by heterogenization/immobilization. It would be beneficial to provide industry and consumers with green alternatives to prior art processes. The presently disclosed technology makes-up for the above and other deficiencies of the prior art.

[0035] In one embodiment, the presently disclosed technology includes an electrolyzer for the production of ethylene glycol (e.g., dimers and trimers) (see, e.g., Figs. 2 and 3).

[0036] Optionally, the catalyst and co-catalyst can be integrated into an electrode as described below, which is implemented into a LPDM electrolyzer. In this electrolyzer, the electrocatalytic cathode electrode can optionally be placed in direct contact with solid electrolyte or cathode membrane (ion-conducting membrane). The cathode membrane can then optionally contact a liquid or porous solid-electrolyte flow compartment where the centerlyte is circulated (or recirculated). The centerlyte flow compartment can optionally be placed in intimate ionic contact with an anode membrane (ion-conducting membrane). An anode electrode can be placed in contact with a circulating anolyte or directly in contact with the anode membrane by any of a variety of means or techniques, such as by compression of the cell assembly, by hot pressing, cold pressing, or the like. In another embodiment, the anolyte contains a supporting electrolyte. In yet another embodiment, the anolyte is a gas. In another embodiment, the electrocatalytic cathode is in contact with a liquid catholyte comprising a supporting electrolyte and the CO2, CO, or inorganic carbon feedstock. In yet another embodiment, the electrocatalytic cathode is in contact with gaseous CO2 or CO or mixtures thereof.

[0037] In one embodiment, in Fig. 1, the phrase “liquid crude” refers to mono-ethylene glycol, di-ethylene glycol, or tri-ethylene glycol or mixtures thereof. Alternatively or additionally, in Fig. 1, the phrase “liquid crude” optionally refers to the product stream with the glycols and any formate and methyl glyoxal, furan diol impurities that will need to be removed later.

[0038] The cathode membrane allows the product selectivity to be tailored. Using anion- exchange membranes allowed for increased production of formate, and small carbon chain diol products (C2 and C3) and suppressed production of the larger C4 molecule, 2,3-furandiol product. This improves the systems profitability by reducing purification needs. The change from 3 to 4 carbon atoms in the product would result in only a small increase in the molecular radius. Since both C3 and C4 products are expected to have similar solvent properties it was unexpected that the C3 product would cross the membrane and the C4 product would not cause a product separation across a semi-permeable membrane. Changes in membrane thickness and pore-sizes is expected to tune the product separation further.

[0039] In one embodiment, the liquid cathode electrolyte contains between 0 and 0.8M alkali or alkali earth cation and carbonate or bicarbonate anions (or a mixture thereof). In another embodiment of the presently disclosed technology, the anion is phosphate, pyrophosphate, sulphate, or borate. A person skilled in the art would understand that he/she can use other supporting electrolytes. In another embodiment, the liquid catholyte contains just water and reaction products or reaction crude. A reaction crude would contain reaction intermediates (formate, formaldehyde, glyceraldehyde, glycoaldehyde, methylglyoxal, and/or furandiol or mixtures thereof), mono/di/tri ethylene glycol or mixtures thereof.

[0040] In one embodiment, the liquid anolyte is either water or an electrolyte containing between 0 and 0.8M alkali or alkali earth cation and sulphate anions (or a mixture thereof). In another embodiment, the anion is phosphate, pyrophosphate, sulphate, or borate. A person skilled in the art would understand that it is possible and even can be beneficial to use other supporting electrolytes. In one embodiment, the liquid anolyte is replaced with a humidified carrier gas flow of air, N2, Ar, or CO2. A person skilled in the art would understand that it is possible to use other carrier gases.

[0041] In one optional embodiment, the electrode is fabricated by dispersion of catalyst powder in a suspension consisting of water, commercial poly-tetrafluoroethylene suspensions (primary particles size from 50-500nm) with anionic surfactants, water, 0-20% by weight of co-catalyst chosen from International Patent Application Publication No. WO 2021/236746 exemplified by boric acid, and 0-50% by dry weight of carbon black (carbon particle size between 30-1500 nm). Optionally, catalyst is then coagulated into a paste by addition of 1 -propanol under continuous agitation. The paste is then optionally applied to a metal mesh support. In one embodiment, this support can be an aluminum 200x200 mesh. In another embodiment, this mesh is a deactivated stainless steel mesh. The resulting electrode is cold or hot pressed to form the final electrode. The final electrode composition can optionally contain from 15-50% dry weight basis polytetrafluroethylene.

[0042] A person skilled in the art would understand that it is possible to use other boronic acid polymers with variations on the polymer backbone to tune boronic acid residue pKA between 7.5 and 9.

[0043] In one embodiment, the presently disclosed technology produces a liquid crude with a low concentration (0.001%-7% product concentration). In another embodiment, the presently disclosed technology produces a liquid crude with a high product concentration (7%-50%) from the catholyte flow compartment of the LPDM-EC system. The cell can be operated at 0.1mA/cm2-5A/cm2 and the product recovered will be a crude containing reaction intermediates (formate, formaldehyde, glyceraldehyde, glycoaldehyde, methylglyoxal, and/or furandiol or mixtures thereof), mono/di/tri ethylene glycol or mixtures thereof, supporting electrolyte with pKa’s in the range of 3-9 for instance such as alkali or alkali earth carbonates, sulphates, phosphates, hypophosphates, citrates, or borates and the in one iteration homogenous co-catalyst and in other iterations residue from the immobilized co-catalyst. In one embodiment, the catholyte contains no supporting electrolyte salt, but the catholyte flow compartment contains a porous solid ion-conducting material for instance made by sintering ion-exchange resin beads, or packing of said beads by compression of the cell. The porous solid ion-conducting material could consist of or include cation exchange resin, an-ion exchange resin beads, or a mixture thereof. In this embodiment, the crude product does not contain any supporting electrolyte for the salt removal step.

[0044] A difference between the embodiment shown in Fig. 2 and that shown in Fig. 3 is the presence of a gap or spacing in the latter. The inclusion or omittance of the gap is the result of how the anolyte is fed. In the embodiment shown in Fig. 2, the feed is from the back penetrating the porous electrode. Therefore, in the embodiment shown in Fig. 2, the anode electrode is in physical contact with the membrane. In contrast, in the embodiment shown in Fig. 3, the liquid is allowed to run in front of the anode, so the anode is physically separated or spaced-apart from the membrane by a gap or spacing. Optionally, in one embodiment, the gap can be between 0.1- 10 mm wide.

Salt-removal unit

[0045] In one embodiment, the electrode-ionization or reverse osmosis first purification step then purifies the reaction crude by removing ionic species such as those of in one embodiment: the supporting electrolyte, the co-catalyst or co-catalyst residue, the formate and or undissociated formic acid intermediate, supporting electrolyte and intermediate derivatives such as fura-(3- nol)-3-carbonate or fura-(2-nol)-3-carbonate esters, carbonate esters of methylglyoxal or its oligomer products as well as some water. In another optional embodiment: the co-catalyst or co- catalyst residue, the formate and or undissociated formic acid intermediate, and intermediate derivatives such as fura-(3-nol)-3-carbonate or fura-(2-nol)-3-carbonate esters, carbonate esters of methylglyoxal or its oligomer products as well as some water. The process diagram of one embodiment of the desalting unit is shown in Fig. 7.

Water removal

[0046] Optionally, final purification to polymer grade MEG is achieved by in one iteration distillation, in another iteration vacuum distillation, and in another iteration pervaporation, or a similar process a person skilled in the arts would know. This step removes water from 99-50% down to < 1 % leaving a MEG product. Further distillation results in the removal of ethylene glycol from the distillate which contains uncharged intermediates such as glycoaldehyde, methylglyoxal, methylglyoxal dimers, trimers or oligomers. The process diagram of one embodiment of the evaporation unit is shown in Fig. 9.

[0047] Optionally, in one embodiment, the evaporation unit shown in Fig. 9 can be divided into a multi-effect evaporator for removal of the majority of the water fraction followed by two vacuum distillation stages for the removal of residual water and removal of the ethylene glycol from the other reaction intermediates such as glycoaldehyde, methylglyoxal, methylglyoxal dimers, trimers or oligomers.

[0048] Fig. 6 in combination with Figs. 7, 8, and 9 shows and describes the process for the production of ethylene glycol in the electrolyzer, the desalting unit, and the evaporation unit. The removal of methyl glyoxal from the ethylene glycol is particularly important as the evaporation shows that methyl glyoxal can co-evaporate with the ethylene glycol in the distillation unit.

[0049] Fig. 7 shows and describes the electrocatalytic conversion step, where the carbon source exemplified by CO2 (but could also be CO or inorganic carbon, for example) is introduced to the cathode and recycled until full conversion is obtained. After the cathode chamber, the liquid crude can be moved with a pump to the desalting unit. The anode electrode can be feed with purified water, which in one embodiment is added a purified salt solution to obtain an ionically conductive solution. The anode feed can be supplied to the anode electrode after which the produced oxygen gas is removed in an anode gas disengager. The liquid anolyte can be recirculated and added fresh water to maintain the ionic conductivity. Anode supporting electrolyte concentrations are maintained from 0.00 IM to 2M and in another embodiment with no added supporting electrolyte (0M).

[0050] The desalting of the reaction crude is shown and described in Fig. 8. The incoming reaction crude can be supplied from an intermediate EDI feed tank, either using a pump or gravity feed. The eletrodeionization unit can then apply a bias to separate ionic species from the reaction crude. Species such as formic acid, formate salts, carbonic acid, bicarbonate, carbonate, and carbonate adducts of the rection products are removed in this step. The desalted product can be sent to an EDI product tank for further processing. The removed salts or ionic compounds can be sent to a concentrate tank and recycled with part of this continuously removed as a waste stream. To regenerate, the EDI a periodic electrode rinse process is performed from an electrode rinse tank.

[0051] After salt removal, the reaction crude can be provided to a pre-heater before entering a vacuum evaporation unit. In one embodiment, this unit consists of a multi-effect evaporator (see, e.g., Fig, 9). The vapor stream can be condensed and sent to the recycling tank for recirculation. The liquid product from the evaporation unit can be supplied to a water removal vacuum distillation unit. The water from the vapor fraction can be condensed and sent to the water tank. The liquid fraction can be sent to a secondary vacuum distillation unit to evaporate the ethylene glycol from other reaction intermediates.

[0052] In one embodiment the presently disclosed technology, by way of example (see, e.g., Figs. 10A and 10B), the desalting unit is shown to reduce the reaction crude conductivity from > 30 mS to essentially 0 mS. The concentration of dethylene glycol (MEG) is shown to increase from 48.7 g/L to approximately 51 g/L, while the presence of formic acid/formate is reduced from approximately 6 g/L to nearly 0 g/L.

[0053] In one embodiment the presently disclosed technology, the liquid crude from the desalting unit is sent to an evaporator. By way of example, Table 1 shows the composition of the reaction crude before and after a single stage vacuum evaporation at 70 degrees Celsius and 120mbar reduced pressure. The presence of inorganic carbon is completely removed. The presence of formic acid/formate is reduced by 17%, while the ethylene glycol product is concentrated from 4% to 62%. The presence of methyl glyoxal is also seen to be largely removed during the evaporation by approximately 81%. In one embodiment, the removal of this highly reactive aldehyde is crucial for the following steps since the methyl glyoxal can contaminate the final ethylene glycol product after distillation.

Table 1: Composition changes after evaporation

[0054] Distillation of a reaction crude is shown by way of example in Fig. 10. The complete removal of water from ethylene glycol in the binary mixture is shown to be completed after 8 hours. The polymer grade specification of ethylene glycol is 99.9 wt% ethylene glycol with less than 0.05wt% water, which is shown to be achieved by the vacuum distillation step.

[0055] In one embodiment, unique features of the presently disclosed technology include:

1) Single-step conversion of carbon dioxide to ethylene glycols (monomer, dimer, or trimer);

2) System incorporates purification, such as combining salt-removal and water removal units (e.g., Fig. 8 and 9);

3) Production of polymer grade ethylene glycols (monomer, dimer, or trimer) from CO2 electrolysis.

4) Cathode membrane allows certain products otherwise produced in other electrolyzer embodiments to be suppressed; and

5) Using a porous solid ion-exchange resin as supporting electrolyte for the Catholyte reduces the needs for product.

[0056] None of the prior art techniques are carbon negative, as is the presently disclosed technology.

[0057] The prior art, including U.S. Patent No. 10,676,833, does not disclose the method or amount of incorporated co-catalyst. The LPDM-EC electrolyzer of the presently disclosed technology allows improved product purity over the generic electrolyzer described in U.S. Patent No. 10,676,833. It would not have been obvious to one of ordinary skill in the art that the use of membranes with pore-sizes significantly larger than the molecular sizes of the product and with no coulombic interaction would allow only some of the small reaction products to be recovered while 1 carbon atom and some longer chain products are retained.

[0058] The single step conversion process of the presently disclosed technology will reduce capital costs and thereby improve profitability. Commercial uses would be the production of monoethylene, di-ethylene glycol, tri-ethylene glycol from CO2 in a single reaction conversion step. The commercial advantage is a product that has a negative carbon foot print a market differentiator (commands a sur-charge in current market), which is not available from other processes now.

[0059] The following exemplary embodiments further describe optional aspects of the presently disclosed technology and are part of this Detailed Description. These exemplary embodiments are set forth in a format substantially akin to claims (each with numerical designations followed by a capital letter), although they are not technically claims of the present application. The following exemplary embodiments refer to each other in dependent relationships as “embodiments” instead of “claims.”

[0060] 1 A. A method comprising: employing a dual membrane electrolyzer containing an electrocatalytic cathode with high selectivity for ethylene glycol, a desalting unit, and an evaporator unit for the electrocatalytic-reduction of carbon dioxide (CO2), carbon monoxide (CO), or inorganic carbon to afford a polymer grade ethylene glycol product.

[0061] 2A. The method of Embodiment 1 A, wherein the electrolyzer produces reaction crude selected from the group consisting of ethylene glycol, methyl glyoxal, formic acid, furandiol, inorganic carbon, and mixtures thereof.

[0062] 3 A. The method of Embodiment 1 A or 2A, wherein the desalting unit is configured to remove the inorganic carbon and the formic acid from the reaction crude.

[0063] 4A. The method of any one of Embodiments 1A-3A, wherein the reaction crude is concentrated to >50% ethylene glycol by evaporation following processing by the desalting unit. [0064] 5 A. The method of any one of Embodiments 1 A-4A, wherein evaporation of water is achieved in a multistage evaporator followed by a dual stage vacuum distillation for removal of residual water and final distillation of the ethylene glycol product.

[0065] 6A. The method of any one of Embodiments 1A-5A, wherein mono-ethylene glycol, diethylene glycol, tri-ethylene glycol, or mixtures thereof is produced.

[0066] 7A. The method of any one of Embodiments 1 A-6A, wherein the production of ethylene glycol is negative in carbon emissions based on life-cycle evaluation from carbon dioxide capture to the ethylene glycol product leaving the process.

[0067] 8A. The method of any one of Embodiments 1 A-7A, wherein the ethylene glycol product is polymer grade according to ASTM standards with amongst others more than 99.9wt% ethylene glycol with less than 0.05wt% water.

[0068] While the presently disclosed technology has been described in detail and with reference to specific examples thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. It is understood, therefore, that the presently disclosed technology is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present presently disclosed technology as defined by the appended claims.

Claims

CLAIMS What is claimed is:

1. A method comprising: employing a dual membrane electrolyzer comprising an electrocatalytic cathode with high selectively for ethylene glycol, a desalting unit, and an evaporator unit for the electrocatalytic -reduction of carbon dioxide (CO2), carbon monoxide (CO), or inorganic carbon to afford a polymer grade ethylene glycol product, wherein the electrocatalytic cathode is in contact with a cathode membrane, which is in contact with a centeriyte, which is in contact with an anode membrane, which is in contact with an electrcatalytic anode, which is in contact with an anolyte.

2. The method of claim 1, wherein the electrolyzer produces reaction crude selected from the group consisting of ethylene glycol, methyl glyoxal, formic acid, furandiol, inorganic carbon, and mixtures thereof.

3. The method of claim 2, wherein the desalting unit is configured to remove the inorganic carbon and the formic acid from the reaction crude.

4. The method of claim 3, wherein the reaction crude is concentrated to >50% ethylene glycol by evaporation following processing by the desalting unit.

5. The method of claim 4, wherein evaporation of water is achieved in a multistage evaporator followed by a dual stage vacuum distillation for removal of residual water and final distillation of the ethylene glycol product.

6. The method of claim 1, wherein the centeriyte comprises a centeriyte solution that contains no supporting electrolyte and the anolyte contains no supporting electrolyte, and an evaporation stage is configured to remove the formic acid and no desalting unit is used.

7. The method of claim 1, wherein mono-ethylene glycol, di-ethylene glycol, triethylene glycol, or mixtures thereof is produced.

8. The method of claim 1, wherein the production of ethylene glycol is negative in carbon emissions based on life-cycle evaluation from carbon dioxide capture to the ethylene glycol product leaving the process.

9. The method of claim 5, wherein the ethylene glycol product is polymer grade with purity specification including more than 99.9wt% ethylene glycol with less than 0.05 wt% water.

10. A system comprising: a dual membrane electrolyzer comprising an electrocatalytic cathode with high selectively for ethylene glycol, a desalting unit, and an evaporator unit for the electrocatalytic- reduction of carbon dioxide (CO2), carbon monoxide (CO), or inorganic carbon to afford a polymer grade ethylene glycol product, wherein the electrocatalytic cathode is in contact with a cathode membrane, which is in contact with a centerlyte, which is in contact with an anode membrane, which is in contact with an electrcatalytic anode, which is in contact with an anolyte.

11. The system of claim 10, wherein the electrolyzer produces reaction crude selected from the group consisting of ethylene glycol, methyl glyoxal, formic acid, furandiol, inorganic carbon, and mixtures thereof.

12. The system of claim 11, wherein the desalting unit is configured to remove the inorganic carbon and the formic acid from the reaction crude.

13. The system of claim 12, wherein the reaction crude is concentrated to >50% ethylene glycol by evaporation following processing by the desalting unit.

14. The system of claim 13, wherein evaporation of water is achieved in a multistage evaporator followed by a dual stage vacuum distillation for removal of residual water and final distillation of the ethylene glycol product.

15. The system of claim 10, wherein the centerlyte comprises a centerlyte solution that contains no supporting electrolyte and the anolyte contains no supporting electrolyte, and an evaporation stage is configured to remove the formic acid and no desalting unit is used.

16. The system of claim 10, wherein mono-ethylene glycol, di-ethylene glycol, triethylene glycol, or mixtures thereof is produced.

17. The system of claim 10, wherein the production of ethylene glycol is negative in carbon emissions based on life-cycle evaluation from carbon dioxide capture to the ethylene glycol product leaving the process.

18. The system of claim 14, wherein the ethylene glycol product is polymer grade with purity specification including more than 99.9wt% ethylene glycol with less than 0.05 wt% water.