Production and Use of Liquid Fuel as a Hydrogen and/or Syngas Carrier

Abstract

The present invention is generally directed to the efficient production of low-carbon methanol, ethanol or mixtures of methanol and ethanol from captured CO.sub.2 and renewable H.sub.2 at a generation site. The H.sub.2 is generated from water using an electrolyzer powered by renewable electricity, or from any other means of low-carbon H.sub.2 production. An improved catalyst and process is described that efficiently converts H.sub.2 and CO.sub.2 mixture to syngas in a one-step process, and alcohols, such as methanol and ethanol, are produced from the syngas in a second step. The liquid methanol and ethanol, which are excellent H.sub.2 carriers, are transported to a production site, where another improved catalyst and process efficiently converts them to syngas. The syngas can then be used at the production site for the synthesis of low carbon fuels and chemicals, or to produce purified low carbon H.sub.2. The low carbon H.sub.2 can be used at the production site for the synthesis of low-carbon chemical products or compressed for transportation use.

Claims

1-30. (canceled)

31. A catalyst for the conversion of methanol or ethanol to syngas, wherein the catalyst is bound to methanol or ethanol, and wherein the catalyst comprises a metal alumina spinel substrate that has a surface area between 50 m.sup.2/g and 150 m.sup.2/g, and wherein the metal alumina spinel substrate is impregnated with one or two of Cu, Mg, Ni, and Zn at a concentration between 1 part-by-weight and 15 parts-by-weight, and wherein the catalyst further includes between 0.1 wt. % and 5 wt. % of La or Ce, and wherein the metal alumina spinel substrate is selected from a group of substrates consisting of magnesium aluminate, calcium aluminate, strontium aluminate, potassium aluminate and sodium aluminate.

32. The catalyst according to claim 31, wherein the metal alumina spinel substrate is magnesium aluminate or calcium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Cu, Mg or both, and wherein the catalyst further includes La.

33. The catalyst according to claim 31, wherein the metal alumina spinel substrate is magnesium aluminate or calcium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Cu, Mg, or both, and wherein the catalyst further includes Ce.

34. The catalyst according to claim 31, wherein the metal alumina spinel substrate is strontium aluminate, potassium aluminate or sodium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Cu, Mg, or both, and wherein the catalyst further includes La.

35. The catalyst according to claim 31, wherein the metal alumina spinel substrate is strontium aluminate, potassium aluminate or sodium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Cu, Mg, or both, and wherein the catalyst further includes Ce.

36. The catalyst according to claim 31, wherein the metal alumina spinel substrate is magnesium aluminate or calcium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Ni, Zn, or both, and wherein the catalyst further includes La.

37. The catalyst according to claim 31, wherein the metal alumina spinel substrate is magnesium aluminate or calcium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Ni, Zn, or both, and wherein the catalyst further includes Ce.

38. The catalyst according to claim 31, wherein the metal alumina spinel substrate is strontium aluminate, potassium aluminate or sodium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Ni, Zn, or both, and wherein the catalyst further includes La.

39. The catalyst according to claim 31, wherein the metal alumina spinel substrate is strontium aluminate, potassium aluminate or sodium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Ni, Zn, or both, and wherein the catalyst further includes Ce.

40. The catalyst according to claim 31, wherein the catalyst includes one or two substitutional solid solutions on the metal impregnated metal-alumina spinel.

41. The catalyst according to claim 31, wherein the catalyst is bound to hydrogen.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIG. 1 shows the overall process showing connection of the generation site (100) and the conversion site (200).

[0052] FIG. 2 shows some of the possible processes that are accomplished at the generation site (100). Block 101 is the electrolyzer block or low carbon H.sub.2 production block. Block 102 is the Reverse Water-Gas Shift (RWGS) reactor system which converts CO.sub.2 and H.sub.2 into syngas (carbon monoxide and H.sub.2). Block 103 is the conversion block that produces the liquid H.sub.2 carrier (e.g., methanol) (stream 4).

[0053] FIG. 3 shows some of the possible process that are accomplished at the conversion site (200). Block 201 is the system for conversion of the liquid H.sub.2 carrier into H.sub.2 and CO.sub.2 or H.sub.2 and CO. Block 202 is the electricity generation block.

DETAILED DESCRIPTION OF THE INVENTION

[0054] In FIG. 1, the generation site is shown as block 100. The generation site has at least three input streams. Stream 1 is an input stream that comprises low carbon electricity which can be generated by renewable sources such as wind and solar, from nuclear power plants, from hydroelectric, or from geothermal power plants. In one embodiment, the low carbon electricity can come from battery storage cells where the batteries were charged with intermittent electricity from wind farms or photovoltaic (PV) arrays. Block 100 may also represent other processes producing low carbon H.sub.2, such as blue H.sub.2, turquoise H.sub.2, or other forms of low carbon H.sub.2.

[0055] Stream 2 is a stream comprising high-purity water. The water can be from any source that meets the water quality specifications required for different electrolysis systems or may be recycled water from the production system.

[0056] Stream 3 is a stream comprising CO.sub.2. CO.sub.2 is available from a nearby carbon capture facility, from a carbon dioxide pipeline, or captured from ambient air. CO.sub.2 can be generated and be captured by several processes generally involving the combustion of fuels, the oxidation of chemicals, gasification processes, petroleum refining, cement production, etc. For example, industrial manufacturing plants that produce ammonia for fertilizer produce large amounts of CO.sub.2. Ethanol plants that convert corn or wheat into ethanol produce large amounts of CO.sub.2 via fermentation. Power plants that generate electricity from various carbonaceous resources produce large amounts of CO.sub.2. Municipal sewage treatment systems using aerobic and anaerobic digestion of sludge produce large amounts of CO.sub.2. All these sources of CO.sub.2 can be used in the current invention.

[0057] The CO.sub.2 in stream 3 (FIG. 1) can be captured via standard means including using amine solvents. Utilization or conversion of CO.sub.2, as described herein, typically involves separating and purifying the CO.sub.2 from a gaseous stream where the CO.sub.2 is not the major component (e.g., exhaust flue gas). Typically, an alkylamine is used to remove the CO.sub.2 from the gas stream. Alkylamines used in the process include monoethanolamine, diethanolamine, methyldiethanolamine, diisopropylamine, aminoethoxyethanol, or combinations thereof. Metal Organic Framework (MOF) materials have also been used as a means of separating CO.sub.2 from a dilute stream using chemisorption or physisorption. Other methods to collect concentrated CO.sub.2 include chemical looping combustion where a circulating metal oxide material captures the CO.sub.2 produced during the combustion process. CO.sub.2 can also be captured from the atmosphere in what is called direct air capture (DAC). The processes for the capture of CO.sub.2 often involve regeneration of the capture materials. Alkylamines are regenerated by being heated, typically by low pressure steam.

[0058] In FIG. 1, block 100 is the overall multi-step process for the generation of the liquid carrier. This is the generation site of the invention. At least one of the products of block 100 is shown as stream 4 which is a stream that comprises the liquid carrier.

[0059] At least a portion of the liquid carrier, stream 4, is transported to another location called the conversion site of the invention shown in FIG. 1 as block 200. The liquid carrier can be moved or transported by many different means to the conversion site. These means include by rail, truck, barge or boat, pipeline, or other methods for transporting liquid fuels, liquid hydrocarbons, or other liquid products. At the conversion site, 200, the liquid carrier, 4, is converted into several potential products.

[0060] FIG. 1 shows a stream comprising low carbon electricity denoted as stream 5 leaving the 200 block. FIG. 1 also shows a stream comprising syngas shown as stream 7 leaving the conversion site, block 200. A stream comprising H.sub.2, shown as stream 6, is one of the products of the conversion site, block 200. Either the H.sub.2 or the syngas may be the primary product of interest.

[0061] FIG. 2 shows some of the possible processes that can be accomplished at the generation site (100). Block 100 is shown as the dashed box around boxes 101, 102, and 103. Block 101 is the low carbon H.sub.2 generation block using electrolysis. Low carbon electricity, stream 1, and a stream comprising purified water, stream 2, are the inputs to the low carbon H.sub.2 generation block, 101. The low carbon H.sub.2 generation block may utilize an electrolyzer, 101, which comprises an anode and a cathode separated by an electrolyte. Different electrolyzers function in slightly different ways. Different electrolyzer designs can be used in the invention including alkaline electrolysis, membrane electrolysis, and high temperature electrolysis. Different electrolytes can be used including liquids KOH and NaOH, and with or without activating compounds. Activating compounds can be added to the electrolyte to improve the stability of the electrolyte. Most ionic activators for the H.sub.2 evolution reaction are composed of an ethylenediamine-based metal chloride complex and Na.sub.2MoO.sub.4 or Na.sub.2 WO.sub.4. Different electro-catalysts can be used on the electrodes including many different combinations of metals and oxides like Raney-Nickel-Aluminum, which can be enhanced by adding cobalt or molybdenum to the alloy.

[0062] Several combinations of transition metals, such as Pt.sub.2Mo, Hf.sub.2Fe, and TiPt, have been used as cathode materials and have shown significantly higher electrocatalytic activity than state-of-the-art electrodes.

[0063] Water at the anode combines with electrons from the external circuit to form oxygen gas, positively charged H.sub.2 ions, and electrons. The H.sub.2 ions pass through the membrane and combine with the electrons from the external circuit at the cathode to form H.sub.2 gas. In this way, both H.sub.2 and O.sub.2 are produced in the electrolyzer. In one embodiment of the invention, multiple electrolyzers are operated in parallel.

[0064] The electrolyzer produces at least two product streams, a H.sub.2 stream 21 (FIG. 2), and an oxygen stream, not shown in FIG. 2.

[0065] Block 102 in FIG. 2 is the RWGS reactor system. In one embodiment of the invention, the multistep process to produce the liquid carrier at the generation site, 100, involves the RWGS reactor where CO.sub.2 is first converted to CO. The RWGS reactor is used to convert the carbon dioxide from stream 3 and electrolyzer H.sub.2, stream 21, into a RWGS reactor product by the endothermic reaction previously denoted by Equation 3.

[0066] The RWGS reactor feed streams, stream 21 and stream 3, are blended in Block 102. The ratio of H.sub.2/CO.sub.2 in the RWGS feed stream is between 2.0 mol/mol to 5.0 mol/mol or more preferably between 3.0 mol/mol and 4.0 mol/mol. The mixed RWGS reactor feedstock must be heated to RWGS operating conditions. In one embodiment, the RWGS feed stream is heated to reaction temperature of greater than 1450? F. (e.g., between 1,450 and 1,800? F.), or preferably greater than 1,550? F. (e.g., between 1,550 and 1,750? F.) using a RWGS feed heater. In one embodiment, the RWGS feed heater is a fired heater that uses the combustion of H.sub.2 taken from stream 21 as the fuel gas that combusts with air to produce water and heat. This heat is used to raise the temperature of the RWGS feed stream.

[0067] In another embodiment, low carbon electricity is used in an electrical heater to raise the RWGS feed temperature. The heater is electrically heated and raises the temperature of the feed gas through indirect heat exchange to greater than 1,550? F. (e.g., between 1,550 and 1,750? F.).

[0068] The heated RWGS reactor feed gas is supplied to a main RWGS reactor. The main reactor vessel is adiabatic or nearly adiabatic and is designed to minimize heat loss. No heat is added to the main reactor vessel.

[0069] The product stream leaving the main RWGS reactor vessel (102) are comprised of CO, unreacted H.sub.2, unreacted CO.sub.2, and H.sub.2O. Additionally, the product stream may also comprise a small amount of methane (CH.sub.4) that was produced as a side reaction.

[0070] The product stream is shown in FIG. 2 as stream 22. Stream 22 can be used in a variety of ways at this point in the process. The product gas can be cooled and compressed and used in downstream process to produce fuels and chemicals (Tan et al, 2018) (Schuetzle et al patents, 2010-2019). The product stream can also be cooled, compressed, and sent back to the preheater and fed back to the main reactor vessel. The product stream can also be reheated in a second electric preheater and sent to a second reactor vessel where additional conversion of CO.sub.2 to CO can occur.

[0071] In other embodiments, where CO is not used in the conversion block, 103, block 102 does not act as a RWGS reactor system but only acts only to mix and heat the feeds for block 103 listed as stream 22 in FIG. 2. In these embodiments, the conversion block, 103, involves the direct hydrogenation of CO.sub.2 to produce a product stream 4.

[0072] Block 103 of FIG. 2 is the conversion block that produces a liquid product (stream 4). In one embodiment, the conversion block comprises a Liquid Fuel Production (LFP) reactor system where the carbon monoxide and the H.sub.2 that are in stream 22 are converted directly to a mixture of liquid hydrocarbons, alcohols or other liquid hydrogen carriers.

[0073] At least a portion of the RWGS product gas is used as the Liquid Fuel Production (LFP) reactor feed. Also, because the operating pressure of the RWGS reactor may be lower than that of the LFP operating pressure, the produced syngas may require compression to the LFP inlet pressure. The LFP is also known as the hydrocarbon synthesis step. The LFP reactor converts CO and H.sub.2 into C.sub.5-C.sub.24 hydrocarbons that can be used as liquid fuels and chemicals and, in this case, produces the liquid carrier, stream 4. Ideally the H.sub.2 to CO ratio in the feed to the LFP reaction is between 1.9 and 2.2 mol/mol but it may be below 1.9 or above 2.2 as necessary to modify the composition of the liquid stream. The LFP reactor is a multi-tubular fixed bed reactor system. The LFP reactor tube profile can be round, oval, flattened, twisted, or other variations. The LFP reactors are generally vertically oriented with LFP reactor feed entering at the top of the LFP reactor. However, horizontal reactor orientation is possible in some circumstances and setting the reactor at an angle may also be advantageous in some circumstances where there are height limitations. Most of the length of the LFP reactor tube is filled with LFP catalyst. The LFP catalyst may also be blended with diluent such as silica or alumina to aid in the distribution of the LFP reactor feed into and through the LFP reactor tube.

[0074] The LFP reactor in one embodiment is operated at pressures between 150 to 450 psig. The reactor is operated over a temperature range from 350? F. to 460? F. and more typically at around 410? F. The LFP reaction is exothermic in which the temperature of the reactor is maintained inside the LFP reactor tubes by the reactor tube bundle being placed into a heat exchanger where boiling water is present on the outside of the LFP reactor tubes. The boiler water temperature is at a lower temperature than the LFP reaction temperature so that heat flows from the LFP reactor tube to the lower temperature water. The shell water temperature is maintained by controlling the pressure of the produced steam. The steam is generally saturated steam. In alternate embodiments, the catalytic LFP reactor can be a slurry reactor, microchannel reactor, fluidized bed reactor, or other reactor types known in the art.

[0075] The CO conversion in the LFP reactor is maintained at between 30 to 80 mole % CO conversion per pass. Unconverted gas can be recycled for extra conversion or sent downstream to an additional LFP reactor. Multiple LFP reactors may also be used in series or in parallel.

[0076] In one embodiment, a series of fractionators are used to create a high cetane diesel fuel with an adjustable flash point, and a stabilized naphtha (potentially a gasoline blend stock or chemical feedstock) or a blended e-crude. The high cetane diesel fuel can be used as a liquid carrier (FIG. 2, Stream 4). The unfractionated liquid hydrocarbon (e-crude) from the LFP reactor can also be used as the liquid carrier.

[0077] In another embodiment, an alcohol synthesis reactor is used as the conversion device of Block 103 (FIG. 2). In this embodiment, the synthesis gas (H.sub.2 and CO) from the RWGS reactor product is converted to a product comprising an alcohol. Methanol is a common alcohol that can be produced from syngas that in some embodiments can be used as a liquid H.sub.2 carrier.

[0078] FIG. 3 shows some of the processes that may be performed at the conversion site. Block 201 is the CO.sub.2 separation block if the conversion process produces CO.sub.2. Block 202 is the electricity generation block.

[0079] The CO.sub.2 separation block (Block 201) comprises a means in which, at a minimum, a stream comprising CO.sub.2 (Stream 7), and a means to produce electricity, shown as stream 23, are produced from the chemical conversion of the liquid carrier, stream 4. Optionally, a stream comprising H.sub.2 shown as stream 6 can be produced in Block 201. Block 201 may comprise multiple steps or processes for the conversion.

[0080] The CO.sub.2 separation block can be accomplished by several means that include steam reforming. In one embodiment, the liquid carrier comprises a system where the liquid carrier, 4, is reacted with steam to produce a product mixture of H.sub.2 and CO.sub.2 that can be separated into streams 6 and 7, respectively. In another embodiment, the liquid carrier can be steam reformed to produce a mixture of H.sub.2 and CO as shown by Equation 7. The H.sub.2 in the steam reformer product can be separated to become stream 6.

[0081] A mixture of water and methanol with a molar concentration ratio (water/methanol) of 1.0-1.5 is pressurized to approximately 300 psig, vaporized, and heated to a temperature of 250-360? C. The H.sub.2 that is created is separated using pressure swing adsorption (PSA), an H.sub.2-permeable membrane, or a palladium alloy. There are two basic methods of conducting this process.

[0082] The water-methanol mixture is introduced into a tube-shaped reactor where it contacts the catalyst. H.sub.2 is then separated from the other reactants and products in a later chamber, either by PSA or through use of a membrane where the majority of the H.sub.2 passes through.

[0083] The other process features an integrated reaction chamber and separation membrane, a membrane reactor. The reaction chamber is made to contain high-temperature, H.sub.2-permeable membranes that can be formed of refractory metals, palladium alloys, or a Pd/Ag-coated ceramic. The H.sub.2 is thereby separated out of the reaction chamber as the reaction proceeds. This purifies the H.sub.2 and, as the reaction continues, increases both the reaction rate and the amount of H.sub.2 extracted.

[0084] With either design, not all the H.sub.2 is removed from the product gases. Since the remaining gas mixture still contains a significant amount of chemical energy, it can be mixed with air and burned to provide heat for the endothermic reforming reaction.

[0085] In one embodiment, the steam reforming system comprises an adiabatic reactor with limited heat loss. The steam reformer feed is heated in a steam reformer heater. In one embodiment, the steam reformer heater is heated to temperature by low carbon electricity through an electrical heater. In another embodiment, the steam reformer heater is heated to temperature by the combustion of H.sub.2 or a combination of H.sub.2, CO, and unconverted vaporized liquid carrier. In another embodiment, the steam reformer is operated at nearly isothermal conditions and the steam reformer feed is fed through multiple tubes that are in a heater fire box. In another embodiment, the steam reforming is performed using waste heat from an industrial facility or co-location facility at the conversion site. The combustion of H.sub.2 or a combination of H.sub.2, CO, and unconverted vaporized liquid carrier provides the heat of reaction. In one embodiment, the steam reformer feed is heated by cross exchange with the steam reformer product and additional heat from the electricity generation block, block 202.

[0086] In another embodiment, the CO.sub.2 conversion block, 201, comprises an oxy-combustion system in which the liquid carrier, stream 4, is reacted with nearly pure oxygen to produce a stream comprising CO.sub.2 and H.sub.2O. The oxy-combustor product stream can be separated such that a CO.sub.2 rich stream, stream 7, is produced. The oxygen is produced by an air separation unit or is available by pipeline.

[0087] In another embodiment, the CO.sub.2 conversion block, 201, comprises a partial oxidation system in which the liquid carrier, stream 4, is reacted with nearly pure O.sub.2 at a rate to accomplish the partial oxidation to a partial oxidation product comprising H.sub.2 and CO. The O.sub.2 to C ratio is controlled to approximately 0.50 to 0.55 on a molar basis to allow the partial oxidation instead of full combustion. This partial oxidation stream can be separated by PSA or other means to produce a nearly pure stream comprising H.sub.2, stream 6. The CO can be converted to CO.sub.2 through water gas shift or through further oxidation such that a stream comprising CO.sub.2 is produced, stream 7.

[0088] Both the oxy-combustion and the partial oxidation embodiments are exothermal under normal operation and require no additional external heat to heat the feed gas to full operating temperature, unlike the steam reforming embodiments.

[0089] The CO.sub.2 conversion reactors often result with product streams that are at elevated temperature. In one embodiment, a heat recovery system can be used to reduce the product gas temperature. Steam is generated in the cooling of the gas. The steam so generated in this embodiment is stream 23 and provides the motive force for the generation of electricity in electricity generating block, 202. In other embodiments, the high temperature heat and some portion of the product gas that is conveyed from the CO.sub.2 conversion reactors can be stream 23 that acts as a feed gas to a solid oxide fuel cell as one embodiment of the electricity generation block, 202.

[0090] The electricity generating block, 202, can be any number of electricity generation systems. These systems may include but are not limited to steam turbine systems, fuel cell systems, gas turbine systems, organic Rankine cycle systems, or Stirling engines systems.

Example 1: Methanol as a H.SUB.2 .and Carbon Dioxide Carrier

[0091] A stream comprising CO.sub.2 is produced by an industrial process or captured from ambient air. This CO.sub.2 stream is fed to a CO.sub.2 capture facility. The CO.sub.2 capture facility uses methyl diethanolamine (MDEA) in an absorber tower to capture the CO.sub.2. Relatively pure CO.sub.2 (FIG. 1, Stream 3) is regenerated from the MDEA by heating.

[0092] Low-carbon electricity from a wind farm, a solar farm, a nuclear power plant, or other low-carbon power sources is available at the site of the carbon capture facility. High-purity water is produced from locally available water. Low-carbon H.sub.2 is produced from the purified water via electrolysis.

[0093] This reaction uses the low-carbon electricity to split the water into H.sub.2 and O.sub.2. The electrolyzer in this example is a PEM Electrolyzer, block 101 in FIG. 2. The electrolyzer produces two streams, H.sub.2 (FIG. 2, Stream 2) and O.sub.2 (stream not shown).

[0094] At the generation site, 100, the improved catalyst and catalytic reactor (FIG. 2, Block 102), is used to convert the captured CO.sub.2 stream and renewable H.sub.2 stream into a product stream 22. In this example, low-carbon electricity, stream 12, is used to supply the electricity to power an electrical heater that raises the RWGS feed stream to about 1650? F. In this example, the H.sub.2 to CO.sub.2 ratio is 3.4/1.0, the pressure is 300 psig, and the space velocity is 20,000 hr.sup.?1. Example 1 provides the relationship between temperature and % CO.sub.2 conversion to CO for the improved RWGS catalyst. The conversion of CO.sub.2 is about 82% under these conditions.

[0095] The product stream, stream 22 (FIG. 2), is compressed to about 50 atmospheres to produce a methanol feed stream. The conversion block, 103, in this example is a methanol reactor system. The H.sub.2 and CO are converted to methanol using a CuZnO based catalyst in a fixed bed reactor operated at about 275? C.

[0096] At least a portion of the methanol produced in the syngas-to-methanol reactor is the liquid carrier, stream 4, and is transported to a second site by rail, truck or by other suitable means, 200 (FIG. 3).

[0097] At the conversion site, the transported methanol is converted to a stream of H.sub.2 and CO.sub.2 by a steam reforming process, 201 (FIG. 3). The transported methanol is first stored in a storage tank. The methanol is pumped from the storage tank, mixed with water, and heated to about 275? C. by indirect heat exchange (where at least one of the reformer heat exchangers is a reformer feed and product cross-exchange heat exchanger in this case). The steam to carbon ratio in the water-methanol mix is controlled to 1.5 on a molar basis. The heated methanol-water mixture is fed to a reformer reactor where the methanol is reacted by the steam reforming reaction shown by Equation 12 to produce CO.sub.2 and H.sub.2.

[00012]$\begin{array}{cc}C{H}_{3}OH\left(g\right)+H_{2}O\left(g\right)=C{O}_2+3H_2?H=+50\mathrm{kJ}/\mathrm{mol}\left(298\mathrm{?K}\right)& \mathrm{Eq}.12\end{array}$

[0098] In this example, the catalyst in the reformer is a PdAg catalyst. In another embodiment, the catalyst is a nickel solid solution catalyst, and in yet another embodiment the catalyst is a metal alumina spinel impregnated with one or more Group I and Group 2 elements.

[0099] The reactor is an adiabatic fixed bed reactor with a pressure drop of less than 25 psig across the reactor and catalyst bed. Over 95% (i.e., between 95% and 100%) of the methanol in the reformer feed is converted to CO.sub.2 and H.sub.2.

[0100] Some water and carbon monoxide are also present in the methanol reformer product. The methanol reformer product is cooled via cross exchange with the reformer feed stream. The methanol reformer product in this example is further processed in a pressure swing adsorption (PSA) unit to recover the H.sub.2. Before the PSA unit, most of the water in the reformer product stream is removed in a knock-out vessel. The knock-out vessel overheads become the feed to the PSA unit. The knock-out vessel bottoms which are predominantly water are recycled and used as a portion of the water that is blended with the methanol stream to produce the methanol reformer feed stream. The pressure swing adsorption unit comprises beds of solid adsorbent to separate impurities from the H.sub.2-rich methanol reformer product stream. The higher-pressure H.sub.2 in the reformer product and PSA feed stream is absorbed on the adsorbent. The adsorbent beds swing between impurity adsorbing and desorbing operations. This leads to a high-pressure PSA product stream that has a composition of over 95 volume % H.sub.2 at a pressure of 176 psig. The low-pressure PSA product is called tail-gas and has a pressure of 20 psig, a molar composition of approximately 22% H.sub.2, 71% CO.sub.2, 5% CO, and 2% water. Overall, through the PSA Unit, 90% of the H.sub.2 in the reformer product stream ends up in the high-pressure PSA product stream, stream 6.

[0101] The low-pressure PSA product stream still has H.sub.2, CO, and a small volume of unconverted vaporized liquid carrier that can be used to produce electricity, stream 23.

Example 2: Ethanol as a CO.SUB.2 .Carrier

[0102] A stream comprising CO.sub.2 is produced by an industrial process or captured from ambient air. This CO.sub.2 stream is fed to a CO.sub.2 capture facility. The CO.sub.2 capture facility uses methyl diethanolamine (MDEA) in an absorber tower to capture the CO.sub.2. Relatively pure CO.sub.2 (FIG. 1, Stream 3) is regenerated from the MDEA by heating.

[0103] Low-carbon electricity from a wind farm, a solar farm, a nuclear power plant, or other low-carbon power sources is available at the site of the carbon capture facility. High-purity water is produced from locally available water. Low-carbon H.sub.2 is produced from the purified water via electrolysis.

[0104] This reaction uses the low-carbon electricity to split the water into H.sub.2 and O.sub.2. The electrolyzer in this example is a PEM Electrolyzer, block 101 in FIG. 2. The electrolyzer produces two streams, H.sub.2 (FIG. 21, Stream 2) and O.sub.2 (stream not shown).

[0105] At the generation site, 100, the improved catalyst #1 and catalytic reactor (FIG. 2, Block 102), is used to convert the captured CO.sub.2 stream and renewable H.sub.2 stream into a product stream 22. In this example, low-carbon electricity, stream 12, is used to supply the electricity to power an electrical heater that raises the RWGS feed stream to about 1650? F. In this example, the H.sub.2 to CO.sub.2 ratio is 3.4/1.0, the pressure is 300 psig, and the space velocity is 20,000 hr.sup.?1. Example 1 provides the relationship between temperature and % CO.sub.2 conversion to CO for the improved catalyst #1. The conversion of CO.sub.2 is about 82% under these conditions with less than 0.50% CH.sub.4 selectivity.

[0106] The product stream, stream 22 (FIG. 2), is compressed to about 50 atmospheres to produce an ethanol reactor feed stream. The conversion block, 103, in this example is an ethanol reactor system. The H.sub.2 and CO are converted to ethanol using three catalysts in tandem reactors [#1: CuZn-Alkali; #2: RhY-Alkali; and #3 (MoPd)]. The products are ethanol (72%); methanol (6%); methane (20%) and acetic acid (2%). (Hurley, Schuetzle et al, 2010).

[0107] At least a portion of the ethanol produced in the syngas-to-ethanol reactor is the liquid carrier, stream 4 (FIG. 2), and is transported to a second site, 200 (FIG. 3). In this example, the liquid is transported by rail or truck to the conversion site, 200.

[0108] The transported ethanol is first stored in a storage tank. The ethanol is pumped from the storage tank at 200 psig, mixed with water, and heated to 260? C. by indirect heat exchange (where at least one of the reformer heat exchangers is a reformer feed and product cross-exchange heat exchanger in this case). The steam to carbon ratio in the water-ethanol mix is controlled to 1.5 on a molar basis. The heated ethanol-water mixture is fed to a catalytic reactor where the ethanol is converted to a stream of H.sub.2 and CO.sub.2, 201 (FIG. 3) as by the steam reforming process shown by Equation 13.

[00013]$\begin{array}{cc}C{H}_{3}C{H}_{2}OH\left(g\right)+3H_{2}O\left(g\right)=2C{O}_2+6H_2?H=+Z\mathrm{kJ}/\mathrm{mol}\left(298\mathrm{?K}\right)& \mathrm{Eq}.13\end{array}$

[0109] In this example, the catalyst in the reformer is a PdAg catalyst. In another embodiment, the catalyst is a nickel solid solution catalyst and in yet another embodiment the catalyst is a metal spinel impregnated with one or more Group I and Group 2 elements.

[0110] The reactor is an adiabatic fixed bed reactor with a pressure drop of 14 psi across the reactor and catalyst bed. Over 99% (i.e., between 99% and 100%) of the ethanol in the reformer feed is converted to H.sub.2 and CO.sub.2. Some H.sub.2O and CO are also present in the ethanol reformer product. The ethanol reformer product is cooled via cross exchange with the reformer feed stream. The ethanol reformer product in this example is further processed in a pressure swing adsorption (PSA) unit to recover the H.sub.2. Before the PSA unit, most of the H.sub.2O in the reformer product stream is removed in a knock-out vessel. The knock-out vessel overheads become the feed to the PSA unit. The knock-out vessel bottoms which are predominantly water are recycled and used as a portion of the water that is blended with the methanol stream to produce the methanol reformer feed stream. The pressure swing adsorption unit comprises beds of solid adsorbent to separate impurities from the H.sub.2 rich methanol reformer product stream. The higher-pressure H.sub.2 in the reformer product and PSA feed stream is absorbed on the adsorbent. The adsorbent beds swing between impurity adsorbing and desorbing operations. This leads to a high-pressure PSA product stream that has a composition of over 99 volume % H.sub.2 at a pressure of 176 psig. The low-pressure PSA product is called tail-gas and has a pressure of 20 psig, a composition by mole of about 22% H.sub.2, 71% CO.sub.2, 5% CO, and 2% H.sub.2O. Overall, through the PSA Unit, 90% of the H.sub.2 in the reformer product stream ends up in the high-pressure PSA product stream, stream 6.

[0111] The low-pressure PSA product stream still has H.sub.2, CO, and a small amount of unconverted vaporized liquid carrier that can be used to produce electricity, stream 23.

Various Processes and Catalysts

[0112] The present invention provides various processes and catalysts. In one aspect, the present invention provides a process A for utilizing captured carbon dioxide at a generation site. The process A involves: producing a hydrogen stream from water using an electrolyzer powered by low carbon electricity; utilizing a carbon dioxide stream from a carbon capture facility or a carbon dioxide pipeline; catalytically converting the hydrogen stream with the carbon dioxide stream to produce a low carbon syngas (e.g., H.sub.2 and CO mixture); catalytically converting the low carbon syngas to a liquid, low carbon H.sub.2 carrier; transporting at least a portion of the liquid (e.g., 10% to 100%) to a production site; catalytically converting the liquid low carbon H.sub.2 carrier to H.sub.2 or syngas.

[0113] The H.sub.2 produced from the liquid H.sub.2 carriers from process A can be used: as a fuel for vehicles; for the production of chemicals; for the production of power; for the production of green diesel; directly to produce low-carbon liquid fuels; directly to produce low-carbon chemicals; in the production of low carbon diesel, naphtha and jet fuel; for the production of low carbon, high-value chemical products; for the production of power.

[0114] The liquid hydrogen carrier produced in process A can be any suitable carrier, including: methanol, ethanol, propanol, a methanol/ethanol mixture, a methanol/propanol mixture, an ethanol/propanol mixture, a methanol/ethanol/propanol mixture, a hydrocarbon naphtha.

[0115] In another aspect, the present invention provides a process B for producing a hydrogen carrier and transporting it to a site where the hydrogen carrier is converted to hydrogen and carbon dioxide or syngas. The process B involves: producing an H.sub.2 stream; producing or obtaining CO.sub.2 that is converted to a CO.sub.2 stream; catalytically converting the H.sub.2 and CO.sub.2 streams to low carbon syngas; catalytically converting the low carbon syngas to a liquid, low carbon H.sub.2 carrier; transporting the low carbon H.sub.2 carrier, or a portion thereof, to a site; catalytically converting the low carbon H.sub.2 carrier at the site to hydrogen and carbon dioxide or syngas.

[0116] The H.sub.2 stream of process B is typically produced from water using an electrolyzer powered by low carbon electricity. In certain cases, the H.sub.2 stream is produced by splitting natural gas into hydrogen and carbon dioxide by steam methane reforming or auto thermal reforming. In other cases, the H.sub.2 stream is produced by pyrolyzing methane using electricity generated heat.

[0117] The low carbon electricity referenced in process B can be produced in any suitable way. It can, for instance be produced from: a wind farm, a solar farm, a nuclear power plant, a hydroelectric power plant, a geothermal power plant, or battery storage cells charged with intermittent electricity from wind farms or solar farms.

[0118] The carbon dioxide converted to a CO.sub.2 stream in process B can be produced and/or captured in a variety of ways, such as: production of CO.sub.2 by and industrial process; capture of CO.sub.2 from ambient air. Nonlimiting examples of industrial processes include: the combustion of fuels, the oxidation of chemicals, a gasification process, petroleum refining, cement production, fertilizer production, ethanol production, power production, or sewage treatment. Capture of CO.sub.2 from ambient air can involve reaction of CO.sub.2 with one or more amine solvents; chemisorption or physisorption of CO.sub.2 with one or more Metal Organic Framework materials; reaction of CO.sub.2 with a metal oxide material; direct air capture.

[0119] In certain cases, the H.sub.2 and CO.sub.2 streams referenced in process B are converted into low carbon syngas in a RWGS reactor. The ration of H.sub.2 to CO.sub.2 fed into the RWGS reactor is between 2.0 ml/mol and 5.0 mol/mol heated to a temperature between 1,450? F. and 1,800? F.

[0120] Oftentimes, the low carbon H.sub.2 carrier of process B is methanol or ethanol. The low carbon gas can be converted into methanol, for example, using a CuZnO-based catalyst; the low carbon gas can be converted into ethanol, for example, using three catalysts in tandem reactors. The three catalysts are CuZn-Alkali, RhY-Alkali and MoPd. It can be transported to another site using any suitable means including, without limitation: rail, truck, barge, boat, or pipeline.

[0121] In certain cases, the low carbon H.sub.2 carrier of process B is catalytically converted to a mixture containing hydrogen and carbon dioxide using a steam reforming process. The steam reforming process uses a catalyst selected from a PdAg catalyst, a nickel solid solution catalyst or a metal alumina spinel impregnated with one or more Group 1 and Group 2 elements.

[0122] In other cases, the low carbon H.sub.2 carrier of process B is catalytically converted to syngas using a catalyst. The catalyst comprises a metal alumina spinel substrate that has a surface area between 50 m.sup.2/g and 150 m.sup.2/g and that is impregnated with one or more of Cu, Mg, Ni, and Zn at a concentration between 1 part-by-weight and 15 parts-by-weight. The catalyst further includes between 0.1 wt. % and 5 wt. % of La or Ce. The metal alumina spinel substrate is selected from a group of substrates consisting of magnesium aluminate, calcium aluminate, strontium aluminate, potassium aluminate and sodium aluminate. The catalyst typically includes one or two substitutional solid solutions on the metal impregnated metal-alumina spinel. Where the H.sub.2 carrier is methanol, it is oftentimes converted to syngas with a per pass efficiency between 60% and 95% at 100-450 psig; 400-550? F. and a space velocity of 5,000-25,000 hr.sup.?1. Where the H.sub.2 carrier is ethanol, it is oftentimes converted to syngas with a per pass efficiency between 45% and 95% at 100-450 psig, 400-550? F. and a space velocity of 5,000-25,000 hr.sup.?1.

[0123] In certain cases, the H.sub.2 carrier in process B is catalytically converted to syngas, which is then used as an LFP reactor feed. The LFP reactor can be a multi-tubular fixed bed reactor system that is vertically oriented with the LFP reactor feed entering at the top of the LFP reactor.

[0124] In another aspect, the present invention provides a catalyst C for the conversion of methanol or ethanol to syngas. The catalyst is bound to methanol or ethanol and comprises a metal alumina spinel substrate that has a surface area between 50 m.sup.2/g and 150 m.sup.2/g. The metal alumina spinel substrate is impregnated with one or two of Cu, Mg, Ni, and Zn at a concentration between 1 part-by-weight and 15 parts-by-weight. The catalyst further includes between 0.1 wt. % and 5 wt. % of La or Ce, and the metal alumina spinel substrate is selected from a group of substrates consisting of magnesium aluminate, calcium aluminate, strontium aluminate, potassium aluminate and sodium aluminate.

[0125] In certain cases, the metal alumina spinel substrate of catalyst C is magnesium aluminate or calcium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Cu, Mg or both, and wherein the catalyst further includes La. In other cases, the metal alumina spinel substrate of catalyst C is magnesium aluminate or calcium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Cu, Mg, or both, and wherein the catalyst further includes Ce. In other cases, the metal alumina spinel substrate of catalyst C is strontium aluminate, potassium aluminate or sodium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Cu, Mg, or both, and wherein the catalyst further includes La. In other cases, the metal alumina spinel substrate of catalyst C is strontium aluminate, potassium aluminate or sodium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Cu, Mg, or both, and wherein the catalyst further includes Ce. In other cases, the metal alumina spinel substrate of catalyst C is magnesium aluminate or calcium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Ni, Zn, or both, and wherein the catalyst further includes La. In other cases, the metal alumina spinel substrate of catalyst C is magnesium aluminate or calcium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Ni, Zn, or both, and wherein the catalyst further includes Ce. In other cases, the metal alumina spinel substrate of catalyst C is strontium aluminate, potassium aluminate or sodium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Ni, Zn, or both, and wherein the catalyst further includes La. In other cases, the metal alumina spinel substrate of catalyst C is strontium aluminate, potassium aluminate or sodium aluminate, and wherein the metal alumina spinel substrate is impregnated with either Ni, Zn, or both, and wherein the catalyst further includes Ce. Catalyst C can include one or two substitutional solid solutions on the metal impregnated metal-alumina spinel. Hydrogen can also be bound to the catalyst.

TABLE-US-00002 U.S. Patent Application Documents 2003/0113244 A1 June 2003 DuPont et al

TABLE-US-00003 U.S. Patent Documents 7,718,832 B1 May 2010 Schuetzle et al 8,394,862 B1 March 2013 Schuetzle et al 8,741,001 B1 June 2014 Schuetzle et al 9,090,831 B2 July 2015 Schuetzle et al 9,476,002 B1 October 2016 Schuetzle et al 9,611,145 B1 April 2017 Schuetzle et al 9,631,147 B1 April 2017 Schuetzle et al 10,478,806 B1 November 2019 Schuetzle et al

TABLE-US-00004 Foreign Patent Documents GB 1995/2279583 A November 1995 Iwanani et al AU 2015/203898 B2 July 2015 Landau et al

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