Major petroleum companies have lately been investing in the development of more refined, more sophisticated technologies directed to the conversion of Coal into substitute natural gas; which substitute natural gas is most often specified to consist of, primarily, Methane.
Why they're making such investments when we are, in the USA, supposedly on the verge of energy independence based on shale gas extraction might seem puzzling, until you consider some of the facts, as exposed for one example by an article in the rather sober science journal, Nature:
Natural gas: The fracking fallacy : Nature News & Comment; "Natural Gas: The Fracking Fallacy", which says, in part: "careful examination of the assumptions behind such bullish forecasts (for shale natural gas)suggests that they may be overly optimistic, in part because the government's predictions rely on coarse-grained studies of major shale formations, or plays. Now, researchers are analysing those formations in much greater detail and are issuing more-conservative forecasts. They calculate that such formations have relatively small 'sweet spots' where it will be profitable to extract gas. The results are “bad news”, says Tad Patzek, head of the University of Texas at Austin's department of petroleum and geosystems engineering, and a member of the team that is conducting the in-depth analyses. With companies trying to extract shale gas as fast as possible and export significant quantities, he argues, “we're setting ourselves up for a major fiasco”.
And, when even a petroleum department head at a major Texas university uses as strong a word as "fiasco" to describe where we might be headed with our shale gas mania, perhaps it makes more sense for oil companies to be making backup plans to salvage the situation based on a fossil energy resource the size of which cannot be debated: Coal.
In any case, again, some of the big oil companies are now hedging against a looming shale gas fiasco by investing in the improvement of technologies like that seen in our report of:
More Texaco Carbon-Recycling Methane from Coal | Research & Development | News; concerning: "United States Patent 3,888,043 - Production of Methane; 1975; Inventors: Edward Child, et. al., CA; Assignee: Texaco Incorporated, NY; Abstract: Continuous process for the production of a gaseous stream comprising at least 90 mole % of methane (dry basis) from a sulfur containing hydrocarbonaceous fuel without polluting the environment ... including the steps of: partial oxidation of the hydrocarbonaceous fuel with air; cooling, cleaning, and purifying the process gas stream to produce a stream of feed gas comprising CO, H2 and containing N2 in the range of about 30 to 60 mole % (dry basis); two separate catalytic methanation steps with an intervening water-gas shift reaction step; and finally separating ... N2 from the process gas stream to produce said methane stream. The large amount of nitrogen diluent in the reacting gas during the methanation step helps to control the normally vigorous exothermic methanation reaction. Claims: The process ... wherein said hydrocarbonaceous fuel is a liquid hydrocarbon selected from the group consisting of ... coal oil; ... coal tar, ... ; and mixtures thereof. The process ... wherein said hydrocarbonaceous fuel is a gaseous hydrocarbon selected from the group consisting of ... coke-oven gas. The process ... wherein said hydrocarbonaceous fuel is an oxygenated hydrocarbonaceous organic material selected from the group consisting of carbohydrates, cellulosic materials, ... waste liquids and by-products from chemical processes containing ... organic materials and mixtures thereof (and/or) a pumpable slurry of solid carbonaceous fuels selected from the group consisting of coal (and) concentrated sewer sludge in a vaporizable carrier such as water ... . This invention relates to a continuous process for the production of a gaseous stream comprising at least 90 mole % methane";
wherein substitute natural gas Methane is synthesized from the products of Coal gasification, and which were already so sophisticated that they allowed for the inclusion of carbon-recycling wastes, like "sewer sludge", with Coal in the initial gasification process.
And, as we assess reports of those newer Coal-to-Methane technologies, one precedent technology they all consistently refer to as precedent art upon which the newer technologies are founded is the United States Patent we make report of herein, which explains how both Carbon Monoxide and Carbon Dioxide, as both might be present in the product of Coal gasification, can be directly converted into substitute natural gas Methane, using a reaction that might enable, as we have previously documented to be feasible, the harvesting of byproduct heat energy from the hydrocarbon synthesis reaction.
Comment follows and is inserted within excerpts from the initial link in this dispatch to:
"United States Patent 4,839,391 - Method and Reactor for Catalytic Methanization of a Gas Containing CO, CO2 and H2
June 13, 1989
Inventors: Jochen Range, et. al., Germany
Assignee: Kernforschungsanlage Julich GmbH and Rheinische Braunkohlenwerke AG, Germany
(Major players in Germany's energy industry. See, for more info:
Forschungszentrum Jülich - Wikipedia, the free encyclopedia; Forschungszentrum Jülich employs more than 4,600 members of staff (2009) and works within the framework of the disciplines physics, chemistry, biology, medicine and engineering on the basic principles and applications in the areas of health, information, environment and energy. Forschungszentrum Jülich GmbH (Jülich Research Centre) is ... one of the largest interdisciplinary research centres in Europe. It was founded on 11 December 1956 by the state of North Rhine-Westphalia as a registered association, before it became "Kernforschungsanlage Jülich GmbH" or Nuclear Research Centre Jülich in 1967. In 1990, the name of the association was changed to "Forschungszentrum Jülich GmbH". And, for those of you who read German:.
Rheinbraun – Wikipedia. "Rheinische Braunkohlenwerke AG" became Rheinbraun which is now a component of the very major German Coal and power producer "RWE", whom we've cited in our reports a few times previously, as in for one example:
Bayer Is Converting Coal Power Plant CO2 Into Plastics | Research & Development | News; concerning:
"Bayer Material Science CO2-to-Plastics Pilot Plant, Germany; In February 2011, Bayer MaterialScience started a new pilot plant (in the) North Rhine-Westphalia state of Germany for producing plastics from carbon dioxide (CO2). It will be used to develop polyurethanes from the waste gas released during power generation. ... Bayer aims to use CO2 as an alternative to production of polymer materials from fossil fuels. ... The CO2 thus acts as a substitute for the petroleum production of plastics. ... The waste carbon dioxide gas is recycled and used as a raw material in the pilot plant. It produces polyether polycarbonate polyols (PPPs), the chemical precursor which is processed into polyurethanes. ... The CO2 feedstock for the pilot plant will be supplied from a lignite power plant in Niederaussem, operated by RWE Power".)
Abstract: A single stage methanization reactor and process are made to yield a product gas of high methane content as well as useful superheated steam without overheating the catalyst bed in which a synthesis gas containing, CO, CO2 and H2 is converted into product gas. A variety of dispositions of vaporizer and superheater portions of the cooling system in the catalyst bed, for which the temperature profiles of gas and coolant along the reactor length are shown and compared, illustrate the principles governing the cooling system for such a reactor. A small portion of the superheated steam is mixed with preheated synthesis gas for elimination of all or part of the carbon monoxide content before the synthesis gas is introduced into the methanization reactor.
(Note that such "synthesis gas", as seen in our report of:
Germany Gasifies Coal with CO2 and H2O | Research & Development | News; concerning: "United States Patent 4,347,064 - Process of Gasifying Fine-Grained Solid Fuels; 1982; Inventors: Lothar Rey, et. al., Germany; Assignee: Metallgesellschaft AG, Frankfurt am Main; Abstract: A process of gasifying fine-grained solid fuels for the production of a product gas that contains hydrogen, carbon oxides and methane comprises a treatment with steam, oxygen and/or carbon dioxide in two interconnected gasifying stages ... . In the first gasifying stage, the fuel is gasified in a circulating fluidized bed ... . The residual solids which become available in the first gasifying stage are fed to the second gasifying stage and are virtually completely gasified therein, except for residual ash, by a treatment with a gasifying agent which includes oxygen. At least one-half of the product gas from the second gasifying stage is fed to the first gasifying stage and used as fluidizing fluid therein. ... A process ... wherein product gas from the first or second fluidized bed stages is purified to remove CO2, and the so separated CO2 is employed as a gasifying agent for (the) fuel ... . A process ... wherein the product gas is used ... as a synthesis gas. ... This invention relates to a process of gasifying fine-grained solid fuels to produce a product gas which contains hydrogen, carbon oxides, and methane, in two interconnected gasifying stages by a treatment with at least one of the gasifying agents consisting of steam, oxygen and carbon dioxide. Solid fuels which may be used in the process include particularly coal ... . At the relatively high gasifying temperatures, carbon dioxide acts also as an oxidizing gasifying agent";
could be made by using Carbon Dioxide, in the first place, to help gasify Coal.)
Claims: Process for catalytic methanization of a synthesis gas containing carbon monoxide, carbon dioxide and hydrogen in a reactor containing a bed of solid catalyst which is cooled by cooling water, wherein said synthesis gas flows, in passing through said catalyst bed, successively through an inflow region for the synthesis gas, a hot spot region and an outward gas flow region of temperature substantially declining along an outward gas flow path therein, said cooling water being converted into steam by the transfer of heat arising from methanization and said steam being superheated in said hot spot region, and wherein: said cooling water flows, in countercurrent to said synthesis gas flowing through said catalyst bed, in a cooling water path includes one complete transit through said catalyst bed, and: the conversion of water from its liquid state into steam is produced by heat transfer both in said outward gas flow region and in said hot spot region.
(The claims go into detail about how heat can be reclaimed from the Methane synthesis reaction, much as seen in our report of:
NASA 2014 CO2 to Methane | Research & Development | News; concerning: "United States Patent 8,710,106 - Sabatier Process and Apparatus for Controlling Exothermic Reaction; 2014; Inventors: Christian Junaedi, et. al., CT; Assignee: Precision Combustion, Inc., CT; Abstract: A Sabatier process involving contacting carbon dioxide and hydrogen in a first reaction zone with a first catalyst bed at a temperature greater than a first designated temperature; feeding the effluent from the first reaction zone into a second reaction zone, and contacting the effluent with a second catalyst bed at a temperature equal to or less than a second designated temperature, so as to produce a product stream comprising water and methane. The first and second catalyst beds each individually comprise an ultra-short-channel-length metal substrate. An apparatus for controlling temperature in an exothermic reaction, such as the Sabatier reaction, is disclosed. Government Support: This invention was made with support from the U.S. government under U.S. Contract No. NNX10CF25P sponsored by the National Aeronautics and Space Administration. The U.S. Government holds certain rights in this invention. ... A process of converting a mixture of carbon dioxide and hydrogen into a mixture of water and methane".)
Process for catalytic methanization of a synthesis gas containing carbon monoxide and hydrogen in a reactor containing a bed of solid catalyst which is cooled by a cooling medium, wherein said synthesis gas flows, in passing through said catalyst bed, successively through an inflow region for synthesis gas, a hot spot region and an outward gas flow region of temperature substantially declining along an outward gas path therein, said cooling medium being converted into vapor by the transfer of heat arising from methanization and said vapor being superheated in said hot spot region, and wherein: said cooling medium flows, in countercurrent to said synthesis gas flowing through said catalyst bed, in a cooling medium path which includes one complete transit through said catalyst bed, and the conversion of said cooling medium from a liquid state into vapor is produced by heat transfer both in said outward gas flow region and in said hot spot region.
(They go into detail about how the reaction is to be cooled, leading to the production of superheated steam in addition to Methane, with obvious implications for the harvesting of energy which could be used to help generate the needed Hydrogen.)
Description and Background: This invention concerns a method and reactor for methanization of a synthesis gas contaning carbon monoxide, carbon dioxide and hydrogen. The methanization takes place in a bed of solid catalyst which is cooled by a cooling medium. In the catalyst bed the synthesis gas flows successively through an inflow region for the synthesis gas, then through a region of higher synthesis gas temperature that is referred to hereinafter as a hot spot region and, finally, through an outward gas-flow region in which the synthesis gas temperatures drop off consistently. The cooling medium which carries away the heat generated in the bed of solid catalyst serves for the generation of vapor and is converted into superheated vapor.
The conversion of a synthesis gas containing carbon monoxide, carbon dioxide and hydrogen, since it runs exothermally, is useful for the recovery of energy. It is known to carry out the conversion of the synthesis gases in internally cooled reactors containing catalysts. The internally cooled reactors have cooling systems through which the cooling medium flows for vapor generation which are disposed with the catalyst bed. The cooling is operated with care to assure that the maximum pemissible operating temperature for the catalyst is not exceeded, so that the catalyst material remains stable.
Internally cooled reactors for methanization of synthesis gas (have been described, as documented, and, it) is known ... to connect two or more reactors one behind the other for the generation of superheated saturated steam in which case one of the reactors, the one through which the synthesis gas first flows, is constituted as an adiabatic reactor and the following reactor as an internally cooled reactor. The heat arising in the internally cooled reactor is removed by vaporization of the cooling medium. The superheating of the cooling medium takes place in heat exchange with the synthesis gas flowing out of the adiabatic reactor.
(As regards "connect(ing) two or more reactors", one of which is "adiabatic", see our report of:
Bayer Improves Fischer-Tropsch Hydrocarbon Synthesis | Research & Development | News; concerning: "United States Patent 8,557,880 - Multi-stage Adiabatic Method for Performing the Fischer-Tropsch Synthesis; 2013; Inventors: Ralph Schellen, et. al., Germany and Texas; Assignee: Bayer Intellectual Property GmbH, Germany; Abstract: The present invention relates to a multistage adiabatic process for performing the Fischer-Tropsch synthesis at low temperatures, in which the synthesis is performed in 5 to 40 series-connected reaction zones under adiabatic conditions. Claims: Process for preparing liquid hydrocarbons from the process gases carbon monoxide and hydrogen, comprising a Fischer-Tropsch synthesis in the presence of heterogeneous catalysts, which is performed in 5 to 40 series-connected reaction zones in which the heterogeneous catalysts are present under adiabatic conditions at temperatures of 220 C to 300 C, wherein downstream of each reaction zone is at least one heat exchange zone through which at least the process gases are passed and around each reaction zone is a thermal insulation zone";
wherein the term is defined, and Bayer Corporation explains how the condition is achieved in a process similar and related to that of our subject, "United States Patent 4,839,391 - Method and Reactor for Catalytic Methanization of a Gas Containing CO, CO2 and H2", but, wherein other, some liquid, hydrocarbons are being synthesized, as opposed to substitute natural gas Methane, from synthesis gas produced by the gasification of Coal.)
(One) methanization process (already) known ... shows no difference from the process just mentioned with regard to the steam or vapor generation in the internally cooled reactor and the superheating of the steam with synthesis gas which is leaving the adiabatic reactor. Of the three reactors through which the synthesis gas passes in succession in these known processes, the first is for the generation of vapor at the vaporization temperature, the second reactor operates adiabatically, and the third reactor is used for heating the cooling medium up to the vaporization temperature. The synthesis gas flowing away from the adiabatic reactor serves for superheating the vaporized cooling medium. Apart from the apparatus expense involved in the provision of several reactors to be passed through one after the other and the arrangement of supplementary heat exchangers for superheating the generated vapor, the known processes also have disadvantages regarding the control and carrying out of the process. It is necessary, in order to prevent overheating the catalyst, to provide intermediate cooling of the synthesis gas between the individual reactors, so that the methanization process as a whole can be carried out only stepwise.
Summary: It is an object of the invention to provide a one-stage process for the methanization of synthesis gas which makes possible both the generation of superheated coolant vapor and also the generation of a methane-rich product gas, while furthermore, making it possible to maintain within the catalyst bed, even in the hot spot region, a sufficient operating temperature which does not impair the stability of the catalyst.
Briefly, the cooling medium is made to vaporize at its boiling temperature at least in the outward gas-flow region of the catalyst bed, and the vapor thereby formed is superheated in the hot spot region of the catalyst bed. By this process management of an extensively constant temperature of the cooling medium in the gas outflow region of the catalyst bed, and likewise the superheating of the generated vapor in the hot spot region can be provided in a simple way in the optimal active region of the catalyst bed. A lower maximum temperature in the hot spot region results when the hot spot region is used for some of the vaporization of the cooling medium. In this case the reaction heat produced in the hot spot region serves not only for producing superheated vapor, but a part of the heat is also absorbed for vaporization of the cooling medium, a feature that facilitates the controllability of the desired course of the process".
First, our take is that this technology was meant to process a Coal-derived synthesis gas that contains some appreciable amount of Carbon Dioxide into substitute natural gas Methane, much as in another German-developed process about which we reported, in:
Germany Coal to Substitute Natural Gas | Research & Development | News; concerning: "United States Patent 4,061,475 - Process for Producing a Gas which can be Substituted for Natural Gas; 1977; Inventor: Friedrich Moller, et. al., Germany; Assignee: Metallgesellschaft AG, Frankfurt am Main; Abstract: A high methane gas which can be substituted for natural gas is produced from a primary gas made by the gasification of coal ... Claims: A process for producing a high-methane gas which can be substituted for natural gas, from a primary gas containing 35-44% by volume hydrogen, 15-20% by volume carbon monoxide and 28-32% by volume carbon dioxide produced by the gasification of coal with water vapor and oxygen ... (and): passing said gas ... through one reaction zone containing only a methanation catalyst containing 20-60% by weight of nickel on a support which is resistant to water vapor, the temperature of the gas (and): supplying the gas leaving the reaction zone to a final methanation stage to produce a high-methane gas; and: removing residual carbon dioxide from said high-methane gas to produce said gas to be substituted for natural gas. ... This invention relates to a process of producing a high-methane gas, which can be substituted for natural gas, from a primary gas which has been produced by a gasification of coal".
The reactions taking place in such a process are a combination of the Sabatier process, as in the above citation of our report concerning NASA's "United States Patent 8,710,106 - Sabatier Process and Apparatus for Controlling Exothermic Reaction", and the reverse water gas shift reaction, as explained in:
Reverse Water-Gas Shift Reaction - Marspedia; "The Reverse Water-Gas Shift Reaction (RWGS reaction) was discovered in the 19th century as a method of producing water from carbon dioxide and hydrogen, with carbon monoxide as a side product. In the context of human missions to Mars, it has been proposed as a complement to the Sabatier/water electrolysis (SE) process to produce methane and oxygen from hydrogen and carbon dioxide on the surface. Alternatively, it can be used with water electrolysis to generate carbon monoxide and oxygen. The oxygen is used for breathing or as oxidizer, while the carbon monoxide can be used as a moderate specific-impulse fuel (with oxygen as the oxidizer) or as a feedstock to generate higher hydrocarbons (Fischer-Tropsch reaction)"; and:
Water-gas shift reaction - Wikipedia, the free encyclopedia; "Reverse water-gas shift: Depending on the reaction conditions, the equilibrium for the water gas shift can be pushed in either the forward or reverse direction. The reversibility of the WGSR is important in the production of ammonia, methanol, and Fischer-Tropsch synthesis where the ratio of H2/CO is critical. Many other industrial companies exploit the reverse water gas shift reaction (RWGS) reaction as a source of the synthetically valuable CO from cheap CO2. Typically, It is done using a copper on aluminium catalyst. The RWGS reaction is also gaining interest in the context of the human missions to Mars primarily for its potential to produce water and oxygen. The Mars atmosphere is about 95% CO2 which can be utilized by the RWGS reaction given a source of hydrogen. Coupling the RWGS with the water electrolysis process will yield methane and oxygen. Post electrolysis, the hydrogen produced can be recycled back into the RWGS reactor for the continued conversion of CO2. Because this reaction is only mildly endothermic, the thermal power needed to drive this reaction can potentially be produced by a Sabatier reactor".
In part to achieve desirable reaction temperatures, CO2 is being converted into Carbon Monoxide, and the Carbon Monoxide is being subsequently converted into Methane; the reactions can proceed in tandem, that is concurrently, or sequentially, in separate, connected reactor vessels; and, that leads to options for temperature control and at least "adiabatic" operation, if not the net production of excess heat energy. .
Thus, it becomes possible to convert, given a supply of Hydrogen, both Carbon Dioxide and Carbon Monoxide - - whether produced in a process of Coal gasification or harvested or produced from other sources, directly, in a combination of reactions that requires no energy to be added, and which might in fact produce enough energy to be harvested and utilized elsewhere - - into substitute natural gas Methane