We've previously documented the expertise of Pennsylvania's Air Products and Chemicals, Incorporated, in the conversion of Coal, via gasification and subsequent catalytic condensation, into various hydrocarbons and "oxygenated" hydrocarbons, i.e., alcohols such as Methanol.
So recognized is their Coal conversion technical knowledge base that they have from time to time been contracted by the USDOE to improve on the art of converting Coal into various liquid hydrocarbon fuels, as seen, for one example, in our report of:
Pennsylvania Converts Even More Coal to Liquid Fuels | Research & Development; concerning, primarily:
"United States Patent 4,411,766 - Iron Catalyzed Coal Liquefaction Process; 1983; Assignee: Air Products & Chemicals, Incorporated, Allentown (PA); Abstract: A process is described for the solvent refining of coal into a gas product, a liquid product and a normally solid dissolved product. The government of the United States of America has rights in this invention pursuant to Contract No. DE-AC22-79ET14806 awarded by the U.S. Department of Energy".
And, very nearly three decades later, their work in the conversion of Coal into liquid hydrocarbons continues, as witness:
Pennsylvania Uses Water to Convert Coal to Hydrocarbons | Research & Development; concerning:
"Patent Application Title: Process for Upgrading Coal Using Supercritical Water; (Date of Publication: August, 2009); Agents and Assignees: Air Products and Chemicals, Inc.; Allentown, PA; Coal is converted into hydrocarbon compounds using supercritical water. The process involves two stages; a first stage in which carbonaceous material is reacted with supercritical water at above 850K to produce a first supercritical fluid reaction mixture comprising hydrocarbon compounds; and a second stage in which hydrocarbon compounds are extracted from coal mixed with at least a portion of the first supercritical fluid. A process for producing hydrocarbon compounds from coal".
We've also documented, from numerous sources, that Coal can, efficiently and on a profitable industrial scale, be converted into the versatile and even strategically important alcohol, Methanol.
As seen, for a few examples, in our reports of:
Texaco 1975 Coal to Methanol | Research & Development; concerning:
"US Patent 3,920,717 - Production of Methanol; 1975; Assignee: Texaco Development Corporation; Abstract: A continuous process for producing methanol including the steps of producing synthesis gas i.e. H2 + CO by the partial oxidation of a hydrocarbonaceous feed (and) wherein said hydrocarbonaceous feedstock is ... coal tar, coal oil, (and) pumpable slurries of coal", and:
West Virginia Coal Association | US Navy Coal + H2O = Low Cost Methanol | Research & Development; concerning the somewhat later:
"US:Patent 4,476,249 - Low Cost Method for Producing Methanol; 1984; Assignee: The Johns Hopkins University; The Government has rights in this invention pursuant to Contract N00024-78-C5384 awarded by the Department of the Navy. Abstract: Method for producing low cost methanol. A source of carbon is provided to an OTEC plant or plantship which is processed to produce carbon monoxide which is reacted with hydrogen to produce methanol. The oxygen and hydrogen are obtained from the electrolysis of water with the required energy supplied by ocean thermal energy conversion. Claims: Method of producing low cost methanol from coal".
Note that the processes for "producing synthesis gas i.e. H2 + CO by the partial oxidation of ... coal", unless adapted in a way similar to that described in our report of:
Exxon Coal + CO2 + H2O Combo Gasification & Conversion | Research & Development; concerning:
"United States Patent 4,318,712 - Catalytic Coal Gasification Process; 1982; Assignee: Exxon Research and Engineering; Abstract: A carbonaceous feed material, a potassium compound having a relatively poor catalytic activity as compared to that of potassium carbonate, and a sodium or lithium salt are introduced into a gasification reactor. A process for the catalytic steam gasification of .... bituminous coal, subbituminous coal, lignite, organic waste materials or similar carbonaceous solids in the presence of added sodium and potassium compounds. It will be understood that the invention ... may be employed in ... gasification operations ... to promote the reaction of steam, hydrogen, carbon dioxide, or a similar gasification agent with (carbon, wherein) the overall cost of the product gas may be substantially reduced";
through the addition of Steam as one of the agents of gasification, which is so effective that CO2-recycling "organic waste materials" and, even, "carbon dioxide" itself can be added to the mix of raw materials, along with Coal, will result in the production of an excess of Carbon Monoxide, relative to Hydrogen, for the Methanol, or other hydrocarbon, synthesis.
That imbalance, if it is undesirable for some reason to add additional Steam, to the initial Coal, and other Carbon, gasification, in order to generate more Hydrogen, can be corrected, of course, by extracting the excess Carbon Monoxide and, perhaps, utilizing it in a process such as that seen in:
Pittsburgh 1951 Carbon Monoxide + Water = Hydrocarbons | Research & Development; concerning:
"United States Patent 2,579,663 - Process of Synthesizing Hydrocarbons; 1951; Assignee: Gulf Research and Development Company, Pittsburgh; Abstract: This invention relates to a process for synthesizing hydrocarbons; more particularly the invention relates to a process for synthesizing normally liquid hydrocarbons from carbon monoxide and steam";
wherein the Carbon Monoxide, CO, can be separately reacted with H2O to synthesize various hydrocarbons.
Herein, though, we see that the Pennsylvania Coal gasification experts at Air Products have devised another way in which a Carbon Monoxide-rich synthesis gas, as made from Coal, can be efficiently employed in the production of Methanol, by productively utilizing excess Carbon Monoxide within the process itself.
Comment follows excerpts from the initial link to:
"United States Patent 5,284,878 - Liquid Phase Methanol Process with CO-rich Recycle
Date: February, 1994
Inventor: David Studer and Elizabeth Schaub, PA
Assignee: Air Products and Chemicals, Incorporated, Allentown
Abstract: Methanol is produced by reacting a CO-rich synthesis gas in the presence of a powdered methanol synthesis catalyst suspended in an inert liquid in a liquid phase reactor system. Unreacted CO-rich synthesis gas is recycled to the reactor, thus increasing methanol production and reducing specific power compared with once-through operation without recycle or compared with recycle of hydrogen-rich gas recovered from unreacted synthesis gas. The process preferably is integrated with a coal gasification electric power generation system in which a portion of the unreacted synthesis gas is used as power generation fuel and a portion of the methanol product is used as additional power generation fuel during periods of peak power demand.
(Note, relative to the above "power generation ... during periods of peak power demand", that, as can be learned via:
West Virginia Coal Association | Germany Co-Produces Methanol & Power from Coal | Research & Development; concerning:
"United States Patent 4,665,688 - Power Generating Station with Integrated Coal Gasification; 1987; Inventors: Ulrich Schiffers and Rainer Muller, Germany; Abstract: Power generating plant with an integratd coal gasification plant, with a heat exchanger and gas purification plant connected to the coal gasifier, with a gas turbine and steam power generating plant part connected to the heat exchanger and gas purification plant, and with a methanol synthesis plant. The methanol generated in the methanol synthesis plant as well as the synthesis exhaust gas of the methanol synthesis can be fed, at least partially, to a further subplant for a second chemical manufacturing process and the excess synthesis exhaust gas from the methanol synthesis and the exhaust from this further subplant, to the combustion chamber of the gas turbine power generating plant"; and:
West Virginia Coal Association | Germany Coal to Electricity, Methanol and Vinyl Acetate | Research & Development; concerning:
"United States Patent 4,663,931 - Power Generating Station with and Integrated Coal Gasification Plant; 1987; Inventors: Ulrich Shiffers and Rainer Muller, Germany; Assignee: Kraftwerk Union, AG, Mulheim; Abstract: Power generating plant with an integrated coal gasification plant, with a heat exchanger and gas purification plant connected to the coal gasifier, with a gas turbine and steam power generating plant part connected to the heat exchanger and gas purification plant, and with a methanol synthesis plant";
it is perfectly feasible to operate a Coal gasification and conversion process, as described herein by Air Products, that, depending upon variable needs and demands, can produce both Methanol and/or electricity in variable relative amounts, depending on the changing relative demand and economics.)
Claims: A method for the production of methanol and fuel gas comprising:
(a) reacting hydrogen and carbon oxides at an elevated pressure in a liquid phase reactor system in the presence of a methanol synthesis catalyst suspended in an inert liquid to yield methanol and unreacted synthesis gas, wherein said hydrogen and carbon oxides are supplied in a reactor feed synthesis gas comprising fresh feed synthesis gas and recycled synthesis gas; and
(b) separating said methanol from said unreacted synthesis gas, and dividing said unreacted synthesis gas into a fuel gas product and said recycled synthesis gas;
The method ... wherein said liquid phase reactor system is integrated with a coal gasification electric power generation system in which said fuel gas product is utilized to generate electric power and at least a portion of said methanol is stored and used as additional fuel to generate electric power during periods of peak electric power demand.
(Note that only "a portion of (the) methanol is stored" for use "as additional fuel" in the power facility.)
The method ... wherein said electric power is generated by one or more gas turbine-driven generators.
The method ... wherein said electric power is generated by one or more fuel cells.
The method ... wherein said methanol synthesis catalyst comprises copper.
Background and Field: The invention pertains to a method for producing methanol from synthesis gas in a liquid phase reactor system, and in particular to the operation of a liquid phase reactor system which utilizes a CO-rich synthesis gas feed to produce methanol and fuel gas.
(To explain more fully, the by-product "fuel gas", which is to be used, in conjunction with a portion of the stored Methanol to generate electricity, is, in fact, the Carbon Monoxide-rich tail, or exhaust, gas from the Methanol synthesis reactor.)
Methanol is produced commercially from hydrogen-rich synthesis gas in a packed bed catalytic reactor operated in the gas phase with means for removing heat from the highly exothermic methanol synthesis reaction. Synthesis gas is shifted when necessary so that the reactor feed is hydrogen-rich and dilute in carbon oxides, typically containing carbon monoxide concentrations no greater than 6 to 9l%. Hydrogen-rich unreacted synthesis gas is recycled back to the reactor in order to moderate the reactor temperatures and increase the overall conversion to methanol.
Unreacted synthesis gas is enriched in hydrogen prior to recycle in certain cases when more unreacted synthesis gas is produced than is needed for the plant fuel system.
The liquid phase methanol (LPMEOH) process can be operated in different modes depending on specific applications. An article by G. W. Roberts et al entitled "The Liquid Phase Methanol Process--an Efficient Route to Methanol from Coal" presented at the Conference on Coal Gasification and Synthetic Fuels for Power Generation, San Francisco, 14-18 April 1985, describes the operation of the LPMEOH process on a once-through basis using unshifted, CO-rich synthesis gas in which the process is integrated with a coal gasifier in a coal gasification combined cycle (CGCC) power generation system. Unconverted synthesis gas is utilized as gas turbine fuel and methanol is stored for use as gas turbine fuel during peak power demand. The LPMEOH process also can be operated in a standalone mode to maximize methanol production. In this case, if CO-rich synthesis gas feed is utilized, the gas must be shifted prior to the reactor to yield the required 2:1 stoichiometric H2 /CO molar ratio for methanol synthesis, and unconverted gas is recycled directly to the reactor to increase overall methanol yield.
(Note: The above phrase, "gas must be shifted", refers to the water gas shift reaction, which, while generating additional Hydrogen, would also co-produce some unwanted Carbon Dioxide. Air Products is avoiding the need for that by their process of our subject herein, "US Patent 5,284,878".)
The present invention is a method for producing methanol and fuel gas from a CO-rich synthesis gas feed in a liquid phase reactor containing a methanol synthesis catalyst suspended in an inert liquid, wherein a portion of the CO-rich unreacted synthesis gas is recycled directly to the reactor feed. This recycle operation increases methanol production and reduces the specific power required for methanol production; the preferred ratio of recycle to fresh feed is between about 0.1 and 2.0. The LPMEOH reactor optionally can be integrated with a coal gasification electric power generation system for the cogeneration of methanol and electric power.
(We are, in fact, uncertain as to how long the "CO-rich unreacted synthesis gas" could be "recycled directly to the reactor feed", without the addition of some extra Hydrogen, before the system would become somewhat overloaded with the Carbon Monoxide. As in our citation above, of "United States Patent 2,579,663 - Process of Synthesizing Hydrocarbons; This invention relates to a process for synthesizing hydrocarbons ... from carbon monoxide and steam";
some Carbon Monoxide could be subtracted for productive use in other processes. Or, as seen in:
NASA Hydrogen from Water and Sunlight | Research & Development; concerning:
"United States Patent 4,045,315 - Solar Photolysis of Water; 1977; NASA; Hydrogen is produced by the solar photolysis of water";
we could probably find a few creative and environmentally-friendly ways to make a little extra Hydrogen, for reaction in the process of our subject with any excess Carbon Monoxide.)
Summary: The present invention is a method for producing methanol and fuel gas from a CO-rich synthesis gas feed in a liquid phase reactor containing a methanol synthesis catalyst suspended in an inert liquid, wherein a portion of the CO-rich unreacted synthesis gas is recycled directly to the reactor feed. This recycle operation increases methanol production and reduces the specific power required for methanol production; the preferred ratio of recycle to fresh feed is between about 0.1 and 2.0. The LPMEOH reactor optionally can be integrated with a coal gasification electric power generation system for the cogeneration of methanol and electric power."
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And, some final thoughts:
Since the process generates both Methanol and Electricity from a synthesis gas consisting of Carbon Monoxide and Hydrogen that's generated from Coal, there seems to us to be some productive potential uses for the co-generated Electricity, above and beyond any needed in the process itself, aside from just feeding it into the "grid".
The co-product power could, instead, be directed into processes such as those disclosed in our reports of:
USDOE Makes Hydrogen by Using Sulfur Dioxide | Research & Development; concerning:
"United States Patent 4,244,794 - Hydrogen Production by the Decomposition of Water; 1981; Assignee: The United States of America; A process for producing hydrogen comprising: passing an electric current from a cathode to an anode through water containing sulfur dioxide so as to produce hydrogen gas at the cathode and so as to oxidize the sulfur dioxide to form sulfuric acid at the anode, thus producing an aqueous solution of sulfuric acid (and) separating said hydrogen gas from said aqueous solution of sulfuric acid"; and:
Standard Oil Electrolyzes CO2 to Carbon Monoxide | Research & Development; concerning:
"United States Patent 4,668,349 - Electrocatalytic Reduction of CO2 by Square Planar Transition Metal Complexes; 1987; Assignee: The Standard Oil Company, Cleveland; Abstract: A process for the electrocatalytic reduction of carbon dioxide comprises immersing a transition metal complex with square planar geometry into an aqueous or nonaqueous solution which has been acidified to a (specified) hydrogen ion concentration ... , adding the carbon dioxide, applying an electrical potential of from about -0.8 volts to about -1.5 volts ... , and reducing the carbon dioxide to carbon monoxide"; or:
More USDOE CO2 "Syntrolysis" | Research & Development; concerning:
"Co-Electrolysis of Steam and Carbon Dioxide for Production of Syngas; 2007; Idaho National Laboratory, USDOE; and Ceramatec, Inc., Utah; Abstract: A research project is underway at the Idaho National Laboratory (INL) to investigate the feasibility of producing syngas by simultaneous electrolytic reduction of steam and carbon dioxide. Syngas, a mixture of hydrogen and carbon monoxide, can be used for the production of synthetic liquid fuels via Fischer-Tropsch processes";
and, thus, use any excess electricity resulting from the process of our subject herein, "United States Patent 5,284,878 - Liquid Phase Methanol Process with CO-rich Recycle", to make more Hydrogen, or Carbon Monoxide, or both, as needed, to add to the "synthesis gas (from) coal gasification", as specified in the full Disclosure by Air Products and Chemicals, so that even more Methanol could be synthesized.
Finally, to beat it to death:
Once we have the Methanol, as produced herein so efficiently from synthesis gas made from Coal, with some additional raw materials, generated from Water and that old greenhouse devil Carbon Dioxide via the use of byproduct electricity, perhaps thrown in, we can, as explained by ExxonMobil, in our report of:
West Virginia Coal Association | ExxonMobil "Coal to Clean Gasoline" | Research & Development; about:
"Coal to Clean Gasoline; ExxonMobil Research and Engineering Company; ExxonMobil's methanol to gasoline technology for the production of clean gasoline from coal. (There is a) commercially proven alternative for converting coal to gasoline, through methanol. ExxonMobil’s methanol-to-gasoline (MTG) process efficiently converts crude methanol to high quality clean gasoline";
efficiently convert that Methanol into Gasoline.
Some closing thoughts and questions:
Doing all of this would require some, significant, investment expense. But:
Would we rather make such a strategic investment in such a technology, a technology that, through the acquisition and use of United States domestic raw material resources, and, through the fuller employment of United States Coal Miners, and chemical plant and transportation workers, would contribute to our overall national United States economy and security; or, would we rather, through the outgoing pipeline to OPEC we've built for our money to pay for our importation of foreign oil, continue to debit our national United States treasury and wealth, and contribute thereby to our, and our children's, deepening impoverishment?