By way of introduction to the subject technology of this dispatch, we are first obliged to remind you of a few of our earlier reports, just as representative examples out of others somewhat related in content.
One is: FMC Corporation Recovers Sulfur from Coal Syngas | Research & Development | News; which divulges: "US Patent 4,302,218 - Process for Controlling Sulfur Oxides in Coal Gasification; 1981; Assignee: FMC Corporation; Abstract: In a fluidized coal gasification process ... SO2 ... in the combustor's flue gas is ... converted to H2S"; wherein we're taught that we can produce Hydrogen Sulfide, H2S, as one by-product of an indirect process for converting Coal, via an initial gasification, into more versatile hydrocarbons.
Another would be: More Pre-WWII CO2 Recycling | Research & Development; which, through the disclosure of: "US Patent 2,128,262 - Carbon Monoxide Manufacture; 1938; Assignee: Semet-Solvay Engineering Corporation; Abstract: An object of this invention is to provide an efficient and economical process for the manufacture of carbon monoxide of high purity by the reduction of carbon dioxide (and wherein) carbon dioxide (is passed) through (an) incandescent body of coke to produce carbon monoxide"; reveals that we can generate plenty of Carbon Monoxide via the seemingly-simple expedient of passing Carbon Dioxide, recovered, perhaps, from the fermentation and distillation operations of a "green" Corn Ethanol production facility, through red-hot Coal.
Note: We understand that we have likely over-cited those two earlier reports in the course of our other dispatches concerning the value and usefulness of Hydrogen Sulfide and Carbon Monoxide, and how we go about getting them.
Rest assured that there are many basic references "out there" confirming the essential facts presented in those reports; and, we will, as time goes on, present additional information based on some of those other references, just to affirm that the bases of the CO and H2S manufacturing technologies disclosed in United States Patents 2,128,262 and 4,302,218 are neither singular nor impractical.
The essential concepts of both have been thoroughly validated by precedent and subsequent art.
So, in any case, given that we can manufacture Hydrogen Sulfide and Carbon Monoxide from some of the notoriously defamed by-products of certain of our productive uses of Coal, herein we learn that one of our most favorite oily giants, ExxonMobil, knows how to combine those two products in a process that generates some truly needful things:
Methane gas and elemental Hydrogen.
We'll further demonstrate the value of those two items, following excerpts from the initial link, above, to:
"United States Patent 4,517,171 - Synthesis of H2 and CH4 from H2S and CO
Date: May, 1985
Inventors: Charles Ratcliffe, NJ, and Petrus Tromp, Amsterdam
Assignee: Exxon Research and Engineering Company, NJ
Abstract: Hydrogen and methane are synthesized from a gaseous feed comprising a mixture of H2S and CO by contacting said feed with a catalyst comprising a sulfided rutile titania ... .
Claims: A process for producing hydrogen and methane from a gaseous feed comprising a mixture of CO and H2S, said process comprising contacting said feed, at a temperature of at least about 275 C with a catalyst comprising rutile titania for a time sufficient to convert at least a portion of said feed to said hydrogen and methane.
Background and Field: This invention relates to producing hydrogen and methane from H2S and CO.
Hydrogen sulfide is an unwanted by-product of many refinery processes, being very toxic and having few practical uses.
(Note: Hydrogen Sulfide, as immediately above, is a pollutant commonly generated in oil refineries.)
In many cases, H2S is disposed of by the Claus Process in which a portion of the H2S is oxidized to SO2.
(Note, conversely, that: In the process of FMC's US Patent 4,302,218, we would be deliberately converting Sulfur Dioxide, SO2, incidentally produced during a process of Coal gasification, back into H2S.)
The remaining H2S is then reacted with the SO2 in the presence of a suitable catalyst to produce H2O and elemental sulfur. H2S can also be reacted with oxygen in the presence of an iron oxide catalyst to form water and elemental sulfur.
(As we have elsewhere documented, processes do exist which would directly manufacture elemental Sulfur in commercially-significant quantities from flue gas Sulfur Dioxide, via Hydrogen Sulfide.)
Summary: The present invention relates to producing hydrogen and methane from a gaseous feed comprising a mixture of H2S and CO by contacting said feed, at a temperature of at least about 275 C, with a catalyst comprising rutile titania for a time sufficient to convert at least a portion of said CO and H2S to hydrogen and methane.
Rutile titania is meant to include mixtures of rutile with other forms of titania, such as anatase, as well as substantially pure rutile.
(Fancy-sounding catalysts, we know; but, fairly easy to come by. Blue diamonds they ain't.)
The rutile titania catalyst must be sulfided for the process of this invention. This sulfiding may be accomplished in-situ in a reactor or the catalyst may be presulfided. Any suitable sulfur containing compound ... may be used (such as) H2S (itself).
In one embodiment the catalyst will be sulfided in-situ by contact with the H2S/CO feed ... .
(Then, we gotta ask: Why bother to even explain it? Sounds like it could just get done automatically.)
As stated above, the present invention relates to producing hydrogen and methane from a gaseous feed comprising a mixture of H2S and CO by contacting said feed with a catalyst comprising rutile titania at a temperature of at least about 275 C. The amount of hydrogen and methane produced by the process of this invention depends on the reaction conditions employed and increases with increasing reaction temperature.
The reaction temperature will generally range from about 275 to 600 C, preferably 300 to 450 C and still more preferably from about 325 to 400 C. However, under some circumstances it may be desireable to operate the process of this invention at temperatures of from 400 - 600 C. (as in) upgrading the methane content of a low BTU gas coming out of a coal or coke gasifier."
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Aha! There, finally, you have the essence of the thing:
According to Exxon, as affirmed by our US Government's expert patent examiners, their invention can be used to make Methane from any un-reacted Carbon Monoxide and any co-generated Hydrogen Sulfide arising from a Coal hydro-, or steam-, according to our extrapolation, gasification process; which process is likely directed towards the production, from Coal, of hydrocarbon synthesis gas which could be intended for catalytic condensation into liquid hydrocarbon fuels and chemicals.
Further, elemental Hydrogen will, as well, apparently, be co-produced, in the course of capturing and utilizing what would otherwise be an un-desirable pollutant, H2S, which could potentially arise from a Coal conversion process directed towards the synthesis of petroleum-
Not demonstrated adequately in our excerpts is the fact that at least some elemental Sulfur will also be extracted, perhaps in quantities of enough commercial value to help offset the total costs of Methane and Hydrogen production.
But, we do confess that we are left somewhat puzzled by the implications the combined reactions have on material balances.
The Oxygen content of the Carbon Monoxide is to be consumed in the co-production of Water (H2O) which is easily removed; but, which process would demand even more of the Hydrogen Sulfide, (H2S), perhaps quite a lot of it, to provide the additional Hydrogen (H2) needed for the total combined production of Water, Methane (CH4) and the free, elemental Hydrogen.
Minds far more competent than ours are needed to decipher all of that and explain it to the rest of us.
However, please allow us - - please afford us the patient attention - - to take it all a few steps further:
Once we have Methane, as herein generated from, for example, excess Carbon Monoxide and unwanted Hydrogen Sulfide arising from a Coal hydro-gasification process intended to generate hydrocarbon synthesis gas, we can, as seen for just one example out of now many, in our report of:
1944 CO2 + H2O + CH4 = Hydrocarbon Syngas | Research & Development; wherein is disclosed: "United States Patent 2,355,753 - Catalytic Apparatus; 1944; Assignee: The M.W. Kellogg Company, NJ; Abstract: The present invention relates ... to the production of a synthesis gas adapted for use in the synthesis of various organic compounds, as for example, the production of a mixture of carbon monoxide and hydrogen for use in the production of hydrocarbons in accordance with the Fischer-Tropsch synthesis reaction ... by the interaction of methane with carbon dioxide";
react that Methane with additional Carbon Dioxide, recovered from whatever convenient source, perhaps a Tar Sand bitumen refinery, and thereby prepare a blend of "carbon monoxide and hydrogen" well-suited "for use in the production of hydrocarbons in accordance with the Fischer-Tropsch synthesis reaction".
And, further, once we have elemental Hydrogen, as herein co-produced, for instance, from Coal-conversion waste gases, along with that nearly-precious Methane, we could sell the Hydrogen, and pipe it, to any nearby oil refinery, who likely need it for the upgrading, the "hydro-treating", of "heavy" crude petroleum.
Or, better, as in:
WVU Hydrogenates Coal Tar | Research & Development | News; concerning: "Hydrogenation of Naphthalene and Coal Tar Distillate; West Virginia University; 2009; Abstract: The hydrogenation of naphthalene and (other) coal-tar distillates has been carried out in a Trickle Bed Reactor, in which the liquid is allowed to flow through the catalyst bed in the presence of hydrogen. The operating conditions employed for the hydrogenation of naphthalene (were varied, and the results monitored, and a) unique peak for naphthalene was observed ... (as was) the peak for the hydrogenated product, tetralin (intended for use in the) production of liquid fuel from solid coal";
we can utilize that Hydrogen - - as can be seemingly obtained, along with Methane, from the Coal conversion waste gases Hydrogen Sulfide and Carbon Monoxide, via the Exxon process of US Patent 4,517,171 - - to hydrogenate the primary Coal, or Coke Oven, tar, Naphthalene; and, thereby create "tetralin", the specific Hydrogen-donor solvent named by WVU in their "West Virginia Process" for the direct liquefaction of Coal