United States Patent: 4476009

 

Herein we see that Texaco, prior to their acquisition by Chevron, continued to develop Coal conversion and liquefaction technologies, as per a number of our previous reports, into the 1980's.

Perhaps of interest in this example is further confirmation of the fact that primary Coal oils can be hydrogenated, through pretty standard petroleum refinery techniques, and thereby made to function as the agents of hydrogenation and liquefaction for more raw Coal.

Of special interest could be the fact that this Texaco process might represent a better way of using such Coal-derived Coal solvents, as opposed to WVU's "West Virginia Process" for the direct liquefaction of Coal, wherein, as we understand it, the primary Coal oil, Naphthalene, is first hydrogenated to form the solvent, Tetralin, which is then used to hydrogenate and liquefy more raw Coal.

As seen in, and as we emphasize following, excerpts from:

 

"United States Patent 4,476,009 - Improving Hydrogen Donor Properties of Coal Liquefaction Solvent

 

Date: October, 1984

 

Inventor: Erven Kuhlmann, et. al., NY

 

Assignee: Texaco, Inc., NY

 

Abstract: A process for improving the properties of a hydrogen donor coal liquefaction solvent employed in a coal liquefaction process which comprises separating said coal liquefaction solvent into a first fraction boiling in the range from about 350 to about 675F, and a second fraction boiling in the range from about 675F to about 1000F, hydrogenating said first fraction (and) hydrogenating said second fraction ... and combining said hydrogenated first and second fractions to provide a coal liquefaction solvent having an increased concentration of hydrogen donor components.

Claims: A process for improving the hydrogen donor properties of a coal liquefaction solvent for a coal liquefaction process.

Field: The invention relates to a hydrogenation process in which different boiling fractions of a coal-derived solvent are subjected to hydrogenating conditions that maximize the concentration of efficient hydrogen-donating hydroaromatics.

A method for treating a coal-derived solvent has now been discovered in which the concentration of efficient hydrogen-donating hydroaromatics is increased. In contradistinction, the prior art hydrogenating processes have, for the most part, sought to maximize without selectivity the concentrations of all hydroaromatics and not just those that have now been found to be more effective hydrogen donors. It was heretofore incorrectly assumed in the prior art that the effectiveness of the solvent was related to the total hydroaromatic content of the solvent. 

It has now been found that not all hydroaromatics are equally as effective in donating hydrogen during the coal liquefaction process. In fact, it has been found that tetralin--a hydroaromatic whose presence was sought to be increased in prior hydrogenating methods and which is considered by the art as a representative hydrogen-donating hydroaromatic--is not as effective in donating hydrogen as, for example, tetrahydrofluoranthene and dihydrophenanthrene: these two hydroaromatics were found to be 1130% and 810%, respectively, more reactive than tetralin ...

The known prior art processes tend to be inefficient in that they serve to increase the concentration of certain hydroaromatic compounds which have been found to be less effective hydrogen donors. Although the prior art recognized that, as a class, all hydroaromatics were much better hydrogen donors than either saturates or aromatics, it was not recognized that certain hydroaromatics were surprisingly superior as hydrogen donors in the specific coal liquefaction process. The prior art liquefaction hydrogenating processes are not selective; whereas, the instant invention is highly selective serving to increase the concentration of more highly effective hydrogen-donating hydroaromatics such as tetrahydrofluoranthene and dihydrophenanthrene.

Summary: Discovery has been made that certain hydroaromatics are more efficient hydrogen donors than other hydroaromatics in a coal liquefaction process, and, also, of a method for maximizing the concentration of these efficient hydroaromatics."

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There is one, perhaps significant, point to be taken from the foregoing, which is:

More than a quarter of a century ago, a major petroleum producer and our US Government knew enough about the processes for converting our abundant Coal into liquid hydrocarbon replacements for petroleum to devise, and to pass judgement on, improvements intended to make those Coal liquefaction techniques "superior", more "selective", more "effective", and, "more efficient".

We must also note, again, as in our introductory comments, that Texaco posits "hydroaromatics such as tetrahydrofluoranthene and dihydrophenanthrene" to be "much better hydrogen donors"; up to "1130%" better, in fact, than the better-known "tetralin" - which is, again as we understand it, both a derivative of the Coal oil naphthalene and the Hydrogen-donor solvent specified by WVU, in their "West Virginia Process" for direct Coal liquefaction.


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