We've thoroughly documented the participation of the FMC Corporation in the US Government-sponsored "COED" indirect Coal liquefaction pilot plant, which operated for a time in New Jersey.
A specific example would be:
FMC Liquefies Coal for USDOE in New Jersey | Research & Development | News, wherein it is, specifically, reported how to convert "coal to low-sulfur synthetic crude oil".
Herein, FMC discloses how they achieved the conversion of Sulfur-containing Coal into such "low-sulfur synthetic crude".
Comment, concerning this, and other, similar, reports to come, follows excerpts from the initial link in this dispatch to:
"United States Patent 4,302,218 - Process for Controlling Sulfur Oxides in Coal Gasification
Date: November, 1981
Inventor: Louis Friedman, NJ
Assignee: FMC Corporation, Philadelphia
Abstract: In a fluidized coal gasification process in which heat for the gasifier is provided by recycle combustor residue from a slagging combustor, SO2 in the combustor's flue gas is removed by contacting the flue gas with the incoming coal feed whereby the SO2 is adsorbed on the coal and converted to H2S in the gasifier. Sulfur is recovered from the H2S in a Claus Plant.
Claims: In the gasification of carbonaceous solids with steam to give product gas containing carbon monoxide and hydrogen wherein the gasification is effected by feeding a stream of said solids and steam into a gasification reaction zone and wherein there is produced in conjunction with said gasification a sulfur dioxide containing flue gas ... the improvement of removing the sulfur dioxide from said flue gas comprising the steps of:
(Contacting) said flue gas with at least a portion of said stream of carbonaceous solids so as to adsorb said sulfur dioxide thereon and produce carbonaceous solids charged with sulfur dioxide and purified flue gas;
(And) venting the purified flue gas;
(And) introducing the so charged carbonaceous solids into said gasification reaction zone whereby the adsorbed sulfur dioxide is reduced to free hydrogen sulfide whereby there is formed a gaseous mixture of said hydrogen sulfide with product gas;
(And) introducing said gaseous mixture into a separation zone wherein the hydrogen sulfide is removed from said gaseous mixture;
(And) recovering said product gas substantially free of sulfur.
The process ... wherein the carbonaceous solids are bituminous coal.
(And) wherein the hydrogen sulfide is treated in a Claus Plant for sulfur recovery.
Description: This invention relates to coal gasification, and in particular to improvements in preventing sulfur in the coal from contaminating the environment.
The gasification of coal with steam to produce a mixture of hydrogen and carbon monoxide (synthesis gas) is well known in the fuel arts and is extensively described in the technical and patent literature. Developed during the latter half of the 19th Century, the technology supplied gas for household and industrial usage.
(The) recent (as written three decades ago) precipitous rise in cost of (petroleum) resources coupled with the recognition they are being rapidly depleted, has revived interest in coal as a raw material from which synthetic fuels and chemical feedstocks can be produced.
It is, therefore, an object of the present invention to effect removal of sulfur dioxide from flue gas produced in conjunction with coal gasification without the difficulties and disadvantages associated with prior methods of purifying gases (and, it) is a further object of the invention to provide a method of removing sulfur dioxide from a flue gas stream produced in a coal gasification plant which method can be carried out on a large industrial scale in a particularly simple and economical manner.
Product gas is conveyed from the gasifier to an alkaline absorption tower where the hydrogen sulfide is removed by conversion to sulfide salts and the resulting purified synthesis gas recovered.
The sulfide salts are reacted to give H2S which is sent to a Claus plant and converted into elemental sulfur. Alkaline absorption tower and Claus plants are standard chemical processing units for removing gaseous sulfur compounds from waste gases and for converting H2S to sulfur, respectively."
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We, in honesty, can't fully understand some of what we must ourselves call the "material balances" involved in this process.
In essence, we believe that any unwanted Sulfur Oxides remaining in the Coal hydro-gasification product stream are recovered by absorbing them onto more raw Coal, and the Sulfur Oxides are then, for the most part, converted in the Coal gasification step, through reactions with Steam, into Hydrogen Sulfide, H2S.
H2S is then treated by an integral "Claus" plant, a common feature at many conventional petroleum refineries where high-Sulfur crude oil is processed, and elemental Sulfur, which has commercial value, is produced as a profitable by-product of the total Coal conversion process.
More information can be found in: Claus process - Wikipedia, the free encyclopedia; wherein we learn, among other, perhaps surprising, things, that:
"The Claus process is the most significant gas desulfurizing process, recovering elemental sulfur from gaseous hydrogen sulfide. First patented in 1883 ..., the Claus process has become the industry standard.
The multi-step Claus process recovers sulfur from the gaseous hydrogen sulfide found in raw natural gas and from the by-product gases containing hydrogen sulfide derived from refining crude oil."
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Does that mean America's Clean Energy Alternative and "crude oil" both have a Sulfur problem?
Apparently so.
And, their Sulfur problem, through the Claus process, was solved long ago; just as, via the FMC process disclosed herein, in combination with the Claus process, any Sulfur problem associated with the indirect conversion of our abundant Coal, into more versatile hydrocarbon fuels, could be solved.
That is, of course, if we finally did decide that we want to, as taught herein by the FMC, "on a large industrial scale" and "in a particularly simple and economical manner", start using our abundant Coal "as a raw material from which synthetic fuels and chemical feedstocks can be produced".
Furthermore, as will be seen in reports to follow, the recycling of unwanted Sulfur Oxides, back into the initial Coal hydro-gasification, to make such commercially-valuable by-product Hydrogen Sulfide, actually improves the efficiency of the Coal gasification itself, and, thus, the subsequent manufacture, as described herein by FMC, from Coal, of such "synthetic fuels and chemical feedstocks".