United States Patent: 3971635

Recently, we provided you with information concerning: ""United States Patent 4,318,712 - Catalytic Coal Gasification Process", which was issued and assigned, in 1982, to Exxon, for a technology which described itself as a "process for the catalytic steam gasification of coal" designed to "promote the reaction of steam (and) carbon dioxide" with Coal; and, with the end product being a fully-hydrogenated hydrocarbon synthesis gas, wherein the "overall cost of the product gas" was "substantially reduced".

Herein, we see that, even a few years earlier, Pittsburgh's own Gulf Oil Corporation, since assimilated into Chevron, had developed it's own, similar, technology for gasifying Coal with Steam; a technique designed to utilize the entire Carbon content of Coal in the production of a fully-hydrogenated synthesis gas suitable in composition for catalytic condensation into liquid hydrocarbons.

And, perhaps as importantly, be alert to the fact, that, as with Exxon's US Patent 4,318,712, inherent in Gulf Oil's Disclosure is further revelation of a fact we have, from many other credible sources, documented:

Carbon Dioxide and Steam, no matter from what sources we obtain them, can be reacted with hot Coal, and made thereby to generate a synthesis gas composed of Hydrogen and Carbon Monoxide that is ideally constituted for catalyzed liquefaction into a variable selection of liquid hydrocarbon fuels and chemicals.

Carbon Dioxide, whether co-generated within the process or supplied from outside sources, can be consumed and utilized in a hydrocarbon synthesis process based on Coal.

That is a fact we emphasize again, in brief comment following excerpts from:


"United States Patent 3,971,635 - Coal Gasifier Having An Elutriated Feed Stream


Date: July, 1976


Inventor: Charles Matthews, PA


Assignee: Gulf Oil Corporation, Pittsburgh


Abstract: A process for gasifying coal to produce carbon monoxide and hydrogen in which a first stream of coal is burned without bed formation in a combustion zone in the presence of water under oxidation conditions to produce gases containing carbon dioxide and steam. A second stream of coal is maintained as a fluid bed in a separate gasifier zone by upflowing carbon dioxide and steam from the combustion zone while being gasified under reducing conditions to produce carbon monoxide and hydrogen. Feed coal for both streams is first passed through a crusher and the crushed coal is elutriated to remove coal fines, which are too small to be retained in the gasifier fluid bed, from coarse particulates. The elutriated fines are water scrubbed to form a slurry which comprises at least in part said first stream of coal entering the combustion zone, while the coarse particulates comprise said second stream of coal.

This invention relates to a process for gasifying coal, coke, or other carbonaceous solids to produce a gaseous mixture which, after removal of carbon dioxide and hydrogen sulfide, is composed mainly of carbon monoxide and hydrogen. The gaseous product may be utilized as a moderate Btu-content fuel; as a reducing gas for metallurgical or chemical purposes; and as an intermediate for conversion to hydrogen for use in chemical processes, in petroleum refineries, in coal conversion plants for manufacture of coal liquids or high Btu-content gas. 

In accordance with the present invention, coal is converted to carbon monoxide and hydrogen by a process which exhibits a minimum potential for polluting. Essentially no water effluent is produced. Water makeup for use within the process as steam for gasification or as wash water may include polluted, solids-containing water from other processes.

Ash, entering as part of the coal feed, is removed from the process in the oxidized form as solidified slag, suitable for landfill or for additional processing to recover valuable minerals. ... Essentially no ash or other solids is rejected to the atmosphere.

Gaseous impurities, having a potential for pollution, which are generated within the process are treated within the process and converted into acceptable forms for sale or disposal, or the impurities are destroyed within the process. For example, sulfur compounds entering the process are converted to hydrogen sulfide directly, or to sulfur dioxide and then to hydrogen sulfide; the hydrogen sulfide is recovered by known processes; and the recovered hydrogen sulfide is converted to elemental sulfur for sale or storage  ... .

(In the gasification zone) carbon dioxide and water vapor react with carbon to produce (additional) carbon monoxide and hydrogen.

Nitrogen compounds entering the process are converted mainly into ammonia, or to nitrogen gas, or to nitrogen oxides and then to ammonia or nitrogen gas; the ammonia is recovered and purified by known processes for sale.

Any traces of oils and tars which may be formed within the process are treated at high temperature to cause thermal cracking and are thereupon converted to gaseous or solid materials which are further reacted to form the desired gas product.

A high degree of process heat economy is achieved by virtually complete gasification of the carbonaceous portion of the feed.

(P)ollutants contained in the slurry water such as phenols, cyanides and other nitrogenous substances, and various sulfur compounds are destroyed in the combustor as a result of combustion with oxygen and exposure to very high temperatures.

The combustor conditions are chosen to generate a maximum of useful heat for the gasifier while avoiding vaporization of excessive amounts of water. As a result, combustor conditions may be chosen (for) combustion primarily to carbon monoxide with a much reduced yield of carbon dioxide.

(The) process can accept and usefully burn undesirable high-sulfur, high-ash combustibles which are byproducts or wastes from other processes, such as the high-sulfur, high-ash solid wastes of a solvent coal liquefaction process."

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Well, Golly !!! - as Gomer used to say. Not only do we have here a Coal conversion process that emits little or no pollution, it is so effective that it can - as we have many times documented to be feasible and to have been practiced - that it can even convert and hydro-gasify the still-carbonaceous "solid wastes" of a different sort of "coal liquefaction process".

And, as we alerted you in our introductory comments, note, again: "carbon dioxide and water vapor", from whatever source we obtain them, perhaps a Coal Country smoke stack, can be made to "react with (hot) carbon to produce ... carbon monoxide and hydrogen", i.e., hydrocarbon synthesis gas.

We do acknowledge that Gulf Oil's technology would result in the generation of some "ash" residue; that is,  the incombustible mineral content in whatever Coal was being utilized.

We submit that such ash would be very similar in composition to that generated by a typical Coal-fired power plant; and, we have apparently accepted and learned how to deal with such relatively-inert residues.

However, we do remind you of the "Cenocell" process, developed by Georgia Tech, about which we have earlier reported and wherein residual ash from Coal combustion can be utilized in the manufacture of a high strength, lighter-weight cement-like composite, which can be used as a direct replacement for conventional concrete in many structural applications.

By the way, we have documented for you, haven't we, what absolutely fabulous quantities of Carbon Dioxide are generated, and released into the atmosphere, by the commercial kilns which convert limestone into the "Portland" cement that is the basic constituent of such conventional concrete?


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