Process of preparing a donor solvent for coal liquefaction - US Patent 4663028 Full Text
We have many times documented the use of "hydrogen donor solvents" in some established Coal liquefaction processes.
West Virginia University in fact, as we have several times reported, specifies the use of the hydrogen donor solvent "tetralin" in their "West Virginia Process" for the direct liquefaction of Coal.
We have also documented that some primary Coal liquids, extracted from Coal "tars" and Coal "oils", long known in the art, such as anthracene and phenanthrene, can, when suitably processed, serve as the hydrogen donor solvents for further Coal liquefaction.
That fact is officially recognized by our United States Government via the US Patent recorded herein, which was issued, as in the following excerpt, more than two decades ago:
"United States Patent 4663028 - Process of Preparing a Donor Solvent for Coal Liquefaction
Date: May 5, 1987
Inventor: John G. Ditman
Assignee: Foster Wheeler USA Corporation
Abstract: A process of preparing a donor solvent for coal liquefaction. Liquefied coal is distilled to separate the coal into a fraction having a boiling point less than about 350° F. and a residue having a boiling point greater than about 350° F. The residue from the distillation is deasphalted in a first solvent capable of substantially extracting from the residue a first oil comprising lower molecular weight compounds and saturated compounds. The residue from the first deasphalting step is then deasphalted in a second solvent capable of substantially extracting from the residue a second oil comprising concentrated aromatic and heterocyclic compounds and leaving in the residue asphaltenes and ash. The second oil can be used as a donor solvent. The second oil extracted in the second deasphalting step is preferably partially hydrogenated prior to use as a donor solvent for the liquefaction of coal.
Claims:
1. A process for preparing a hydrogen donor solvent having a high concentration of higher molecular weight polycyclic aromatic and heterocyclclic compounds suitable for use in coal liquefaction.
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10. The process of claim 1, wherein the ... coal ... has been liquefied in the presence of said donor solvent.
Background: The present invention relates generally to coal liquefaction and, more particularly, to a process of preparing a donor solvent for coal liquefaction.
In the liquefaction of coal, it is desirable to use a donor solvent that is an efficient hydrogen transfer agent to hydrogenate at least partially the coal being liquefied. The donor solvent helps to saturate the various hydrocarbon compounds being formed during the coal liquefaction. It is also highly desirable that the donor solvent be derived from the coal feedstock to render the donor solvent more compatible with the coal feedstock and the various by-products of the coal liquefaction.
Summary: Quite surprisingly, the inventor has discovered a process that effectively produces a donor solvent that can be successfully used in the liquefaction of coal. More specifically, the present invention is directed to a process of preparing a donor solvent for coal liquefaction. The claimed process comprises the steps of: (a) distilling liquefied coal ... ; (b) deasphalting the residue from the distillation in a first solvent capable of substantially extracting from the residue a first oil comprising lower molecular weight compounds and saturated compounds; and (c) deasphalting the residue from the first deasphalting step in a second solvent capable of substantially extracting from the residue a second oil comprising concentrated aromatic and heterocyclic compounds and leaving in the residue asphaltenes and ash. The second oil can be directly used as a donor solvent for the liquefaction of coal or it can first be partially hydrogenated."
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As usual, the full patent is replete with many technical details that are beyond our current scope. However, it should by now be clear: The science for liquefying our vast reserves of Coal into the liquid hydrocarbon fuels we need is, in certain circles, well-known and highly-developed; even to the point of utilizing Coal liquefaction products in the further liquefaction and hydrogenation of additional raw Coal.
What isn't clear, at all, to us, is why such highly-developed Coal liquefaction science and technology isn't now being employed to free us all, all of us United States citizens, from overseas OPEC economic shackles and petroleum industry profiteering.