We've many times documented the fact that Coal can be gasified, reacted, with Steam; and, be made thereby to form a "synthesis gas", or "syngas", that contains, predominantly, Hydrogen and Carbon Monoxide, in variable amounts and ratios; and, which ratios can be controlled to an appreciable extent, so that the resultant synthesis gas is suitable for catalytic, chemical condensation into specific types and ranges of both liquid and gaseous hydrocarbons.
One example of such technology that was developed early on, by a company that later became a part of Exxon, and then of ExxonMobil, can be seen in our report of:
Standard Oil 1952 Coal + Steam = Hydrocarbons | Research & Development; in
which is detailed: "United States Patent 2,582,710 - Conversion of Carbonaceous Solids into Volatile Products; 1952; Assignee: Standard Oil Development Company, DE; Abstract: The present invention relates to the conversion of carbonaceous solids into volatile products (by their) gasification ... with steam."
Coal, of course, would be one of our more quintessential "carbonaceous solids".
But, keep in mind that things like charcoal, derived from wood or other biomass, would also qualify; thus introducing potentials for Carbon recycling and a certain amount of sustainability.
That said, the descendant companies of Standard Oil continued their development of such technology, and refined it to the point where specific and relatively pure blends of Hydrogen and Carbon Monoxide synthesis gas could be generated; blends so pure that they could be condensed not just into relatively crude liquid hydrocarbons, suitable for standard petroleum refinery treatment to make various petroleum product substitutes, but, suitable as well for use in a variety of more sophisticated conversions, to make various "finer" chemical manufacturing raw materials, as substitutes for what we all have come to refer to as "petrochemicals".
Comment, with additional references, follows, and is inserted within, excerpts from the initial link in this dispatch to:
"United States Patent 4,211,669 - Production of a Chemical Synthesis Gas from Coal
Date: July, 1980
Inventors: James Eakman, et. al., TX and NJ
Assignee: Exxon Research and Engineering Company, NJ
Abstract: A high purity chemical synthesis gas is produced by reacting steam with a carbonaceous feed material in the presence of a carbon-alkali metal catalyst and substantially equilibrium quantities of added hydrogen and carbon monoxide at a temperature between about 1000F and about 1500F and a pressure in excess of about 100 psi to produce a raw product gas consisting essentially of equilibrium quantities, at reaction temperature and pressure, of methane, steam, carbon dioxide, carbon monoxide and hydrogen; withdrawing the raw product gas from the gasifier and treating it for the removal of steam and acid gases to produce a treated gas containing primarily carbon monoxide, hydrogen and methane; recovering carbon monoxide and hydrogen from the treated gas as a chemical synthesis product gas; mixing the remainder of the treated gas consisting essentially of methane with steam; passing the resultant mixture into a steam reforming furnace where the methane reacts with the steam to produce carbon monoxide and hydrogen; and passing the effluent from the reforming furnace into the gasifier.
(We are compelled to interrupt here. Note that "acid gases", which would include Carbon Dioxide, are to be removed, while the Methane is to be reacted "with ... steam to produce" more of the desired "carbon monoxide and hydrogen".
We submit that the recovered Carbon Dioxide could be productively dealt with in a number of ways.
First, at least some of the CO2 could be added to the above-specified reaction of Methane with Steam, as in, for just one example, out of now many we've documented, our earlier report of:
Standard Oil 1950 CO2 + CH4 + H2O = Syngas | Research & Development; wherein Standard Oil itself affirms, via disclosure of the process of: "US Patent 2,522, 468 - Production of Synthesis Gas; 1950;
Assignee: Standard Oil Development Company; Abstract: (The) production of a mixture of carbon monoxide and hydrogen suitably proportioned for use as a feed-gas in the synthesis of hydrocarbons ... , including those boiling in the gasoline and gas oil range, by reacting a mixture of carbon monoxide and hydrogen (obtained by) charging a mixture of methane, steam and carbon dioxide to a reforming zone containing (a specified) catalyst (under specified conditions) ... and recovering from said zone, a product gas containing ... carbon monoxide and hydrogen";
wherein the added Carbon Dioxide could participate in the "reforming furnace" Methane-Steam reactions specified by our subject "United States Patent 4,211,669"; and, be made thereby to help form even more "synthesis gas".
Or, alternatively or additionally, the CO2 recovered via our "USP 4,211,669" process, i.e., any CO2 that might remain, perhaps after any such reactions with the co-produced Methane to form additional synthesis gas, could simply be recycled back into the initial reaction of "steam with a carbonaceous feed"; wherein, as seen in:
More Oklahoma CO2 + Coal = Hydrocarbon Syngas | Research & Development | News; concerning: "United States Patent 4.040,976 - Process of Treating Carbonaceous Material with Carbon Dioxide; 1977; Assignee: Cities Service Company; Abstract: A mixture of carbon dioxide and a carbonaceous material, such as coal, is rapidly heated in a reactor, giving a gaseous effluent comprising carbon monoxide";
the remaining, recovered CO2 could participate in the Exxon process's initial, specified reaction of "steam with a carbonaceous feed material", and thereby serve to generate even more of the Carbon Monoxide component of that desired "chemical synthesis gas".)
Claims: A process for the production of a chemical synthesis product gas from a carbonaceous feed material and steam which comprises: reacting said steam with said carbonaceous feed material in a reaction zone at a (specified) reaction temperature (and) pressure ... in the presence of a carbon-alkali metal catalyst and sufficient added hydrogen and carbon monoxide to provide substantially equilibrium quantities of hydrogen and carbon monoxide in said reaction zone at said reaction temperature and said reaction pressure;
(Note: The "added hydrogen and carbon monoxide" is produced by the process of "US Patent 4,211,669", itself; and, it is a portion of the product gas which is recycled back to the gasification zone to, in some way we don't fully understand, help improve the processing of the Coal.)
(And) withdrawing from said reaction zone an effluent gas containing substantially equilibrium quantities, at said reaction temperature and pressure, of methane, carbon dioxide, steam, hydrogen and carbon monoxide;
(And) treating said effluent gas for the removal of steam and acid gases to produce a treated gas containing primarily carbon monoxide, hydrogen and methane;
(And) recovering substantially all of the carbon monoxide and hydrogen from said treated gas as a chemical synthesis product gas, thereby producing a gas comprised substantially of methane;
(And) contacting (that) methane with steam in a steam reforming zone under conditions such that at least a portion of the methane present reacts with said steam to produce hydrogen and carbon monoxide;
(And) passing the effluent from said steam reforming zone into said reaction zone without substantial cooling, thereby supplying said added hydrogen and carbon monoxide required in said reaction zone and wherein said reforming zone is operated at conditions such that the heat content of said effluent from said steam reforming zone is sufficient to supply substantially all of the heat needed to preheat said carbonaceous feed material to said reaction temperature.
(And) wherein said carbonaceous feed material comprises coal.
(At last we got to our favorite four-letter word. Note, that, as in: "the heat content of said effluent from said steam reforming zone is sufficient to supply substantially all of the heat needed to preheat said carbonaceous feed material", in a way similar to other, related Coal conversion technologies we've documented for you, whereby heat energy generated in one stage of the total process can be reclaimed and recycled back into other stages, to help drive other needed reactions; contributing thereby to an increased efficiency, with attendant cost savings, one must suppose, for that total Coal gasification process.)
A process for the production of a chemical synthesis product gas from coal and steam.
Description and Background: This invention relates to the gasification of coal and similar carbonaceous materials and is particularly concerned with a catalytic gasification process carried out in the presence of a carbon-alkali metal catalyst to produce a chemical synthesis gas.
Existing and proposed processes for the manufacture of synthetic gaseous fuels from coal or similar carbonaceous materials normally require the reaction of carbon with steam, alone or in combination with oxygen, at temperatures between about 1200F and about 2500F to produce a gas which may contain some methane but consists primarily of hydrogen and carbon monoxide. This gas can be used directly as a synthesis gas or a fuel gas with little added processing or can be reacted with additional steam to increase the hydrogen-to-carbon monoxide ratio and then fed to a catalytic methanation unit ... to produce methane.
It has been shown that processes of this type can be improved by carrying out the initial gasification step in the presence of a catalyst containing an alkali metal constituent. The alkali metal constituent accelerates the steam-carbon gasification reaction and thus permits the generation of synthesis gas at somewhat lower temperatures than would otherwise be required. Processes of this type are costly because of the large quantities of heat that must be supplied to sustain the highly endothermic steam-carbon reaction. One method of supplying this heat is to inject oxygen directly into the gasifier and burn a portion of the carbon in the feed material being gasified. This method is highly expensive in that it requires the existence of a plant to manufacture the oxygen. Other methods for supplying the heat have been suggested, but these, like that of injecting oxygen, are expensive.
(Although Exxon has their own way of supplying the needed heat, we remind you of one alternative that, after an initial investment, might enable the supply of at least some of that heat, without combusting valuable Carbon and Hydrogen constituents, and without generating any additional Carbon Dioxide which must then be recycled into the process, as seen in:
USDOE Hydrogasifies Coal with Solar Power | Research & Development; which concerns: "United States Patent 4,415,339 - Solar Coal Gasification Reactor; 1983; Assignee: The USA, as represented by the Department of Energy; Abstract: Coal (or other carbonaceous matter, such as biomass) is converted into a duct gas that is substantially free from hydrocarbons. The coal is fed into a solar reactor, and solar energy is directed into the reactor onto coal ... . Steam, injected into the reactor adjacent to the gasification zone, reacts with char ... . Solar energy supplies the energy for the endothermic steam-char reaction. The product gas will be free of tar and other hydrocarbons, and thus be suitable for use in many processes. (This is a) method of producing a substantially hydrocarbon-free product gas with a solar reactor from a carbonaceous-material feed ... (and) wherein the feed is coal and includes water (and) ... one reactive gas selected from the group consisting of steam, CO2, H2 and CH4 ... ."
In fact, so generous is the supply of energy in US Patent 4,415,339, that even more recovered CO2 than is already contemplated in Exxon's process of our subject US Patent 4,211,669 for recovery and reuse could likely be recycled into the initial Coal gasification reactor.)
Summary: This invention provides a process for the generation of a high purity chemical synthesis gas by the substantially thermoneutral reaction of steam with coal ... and other carbonaceous feed materials in the presence of a carbon-alkali metal catalyst and added hydrogen and carbon monoxide.
(Again: The "other carbonaceous feed materials" could well be of Carbon-recycling botanical origin. And, the "added hydrogen and carbon monoxide" are generated within the process of the invention itself; we don't have to go out and find or make them separately.)
In accordance with the invention, it has now been found that a chemical synthesis gas can be generated by reacting steam with a carbonaceous feed material in a reaction zone at a temperature between about 1000F and about 1500F and a pressure in excess of about 100 psi, ... in the presence of a carbon-alkali metal catalyst and sufficient added hydrogen and carbon monoxide to provide substantially equilibrium quantities of hydrogen and carbon monoxide in the reaction zone at reaction temperature and pressure thereby producing a effluent gas consisting essentially of equilibrium quantities, at reaction temperature and pressure, of methane, carbon monoxide, carbon dioxide, steam and hydrogen; withdrawing the effluent gas from the reaction zone and treating it for the removal of steam and acid gases to produce a treated gas containing primarily carbon monoxide, hydrogen and methane; recovering carbon monoxide and hydrogen from the treated gas as a chemical synthesis product gas; contacting at least a portion of the remainder of the treated gas consisting primarily of methane with steam in a steam reforming zone under conditions such that at least a portion of the methane reacts with the steam to produce carbon monoxide and hydrogen; and passing the effluent from the reforming zone into the reaction zone.
(Recycling, in other words, the "carbon monoxide and hydrogen" made by reacting just "a portion of the methane" produced in the system by the processing of that Methane with Steam.
The remainder of the Methane could, we again submit, as we reported in another instance via:
Pittsburgh 1941 CO2 + Methane = Hydrocarbon Syngas | Research & Development | News; concerning: "United States Patent 2,266,989 - Manufacture of a Gas from CO2 and Methane; 1941; Assignee: Koppers Company, Pittsburgh, PA; Abstract: The present invention relates to the manufacture of gases suitable for the synthesis of higher hydrocarbons ... by reacting on methane ... with carbon dioxide or a mixture of carbon dioxide and steam, so that the methane ... is decomposed into hydrogen and carbon monoxide (which is) a gas suitable for the synthesis of hydrocarbons";
be reacted with more Carbon Dioxide, recovered from whatever source, with or without the addition of Steam, and be made thereby to form a blend of more Carbon Monoxide and Hydrogen, i.e., more hydrocarbon synthesis gas.)
The catalytic effect of carbon-alkali metal catalysts on the gas phase reactions, as distinguished from the solid-gas reactions or the reactions of carbon with steam, hydrogen or carbon dioxide, allows the following exothermic reactions to contribute substantially to the presence of methane in the effluent gas and drastically reduces the endothermicity of (some of the specified) reaction(s).
Under the proper operating conditions, these reactions can be made to take place within the gasification zone and supply large amounts of methane and additional exothermic heat which would otherwise have to be supplied by the injection of oxygen or other means.
(Which forestalled "injection of oxygen", made unnecessary by the overall reaction's "exothermic heat", could otherwise lead to the attendant generation of more unwanted, unneeded Carbon Dioxide.)
The process of the invention, unlike similar processes proposed in the past, utilizes the thermoneutral reaction of steam with a carbonaceous feed material to produce a high purity chemical synthesis gas that has wide spread industrial applications."
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As should be obvious, this is a sophisticated process that not only maximizes production of the "high purity" Carbon Monoxide and Hydrogen, but, which, also supplies most of its own energy requirements, and, which, not only forestalls Carbon Dioxide emissions of its own, but may, in fact, allow Carbon Dioxide recovered from sources external to the system to be added to it.
In that regard, our subject Exxon United States Patent 4,211,669, issued in 1980, could be seen as precedent to another, later and closely-related Exxon technology, about which we've earlier reported, as in:
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 ... and a sodium or lithium salt are introduced into a gasification reactor. The carbonaceous material is then gasified ... in the presence of (the) added sodium and potassium compounds (which) promote the reaction of steam, hydrogen, carbon dioxide, or a similar gasification agent with" the Coal;
and, wherein, again, Carbon Dioxide, recovered from whatever source, can be employed as one of the agents of Coal gasification to improve the production of a desired mix of Carbon Monoxide and Hydrogen.
Which mix of Carbon Monoxide and Hydrogen, we are compelled to infer from the full Disclosure of our subject "US Patent 4,211,669", can be designed and specified, by adjusting the relative amounts of Coal, Steam, and Carbon Dioxide, and any Carbon Monoxide and Hydrogen from the specified co-product Methane decomposition, that go into the initial gasification zone; so as to, through a nearly "thermoneutral" process, generate a final "high purity chemical synthesis gas" which can be designed, as desired, for the catalytic synthesis of, we suggest, virtually anything, such as Methane, Methanol, or the various components of Gasoline, that we are now compelled to obtain from increasingly expensive and increasingly risky sources of natural Petroleum.