We've documented, to the point of tedium, we're certain, the fact that South Africa Synthetic Oil Limited, SASOL, has, in Africa, been making liquid transportation fuels - direct replacements for all those fuels traditionally derived from petroleum - in multiple facilities, and for many years, out of Coal.
They we're doing so long before the US Patent we reveal herein was issued; but, we see that, very nearly three decades ago, our United States Government agreed that SASOL had refined their Coal conversion technology to the point where, essentially, 100% of the Carbon content in the Coal is converted into liquid hydrocarbons.
Unlike some related Coal liquefaction technologies, very little of the Carbon is "lost" to the co-production of Methane; or, to the formation of a solid residue which would require further treatment to effect complete conversion.
The technology is a "direct" Coal conversion process, unlike the Fischer-Tropsch indirect Coal conversion technology that was, with later WWII innovations, we believe, used by SASOL to first establish their Coal conversion industry in South Africa.
Moreover, it uses technology similar in many respects to others we have already documented for you, as we emphasize following excerpts from:
"United States Patent 4,251,346 - Process for Coal Liquefaction
Date: February, 1981
Inventor: Leonard Dry, et. al., South Africa
Assignee: SASOL One, Proprietary, Limited, Orange Free State
Abstract: The invention provides a process for the liquefaction of coal. The comminuted coal is slurried in a solvent or pasting oil and digested ... . The solvent or pasting oil is obtained wholly or mostly by recycling from the distilled fractionation of the reaction products. ... The process can be controlled so that the coal is converted virtually completely into distillable products, more particularly predominantly in the crude diesel fuel range.
Claims: Process for converting coal directly into predominantly gaseous to liquid products suitable for making hydrocarbon fuel ... .
The process for converting coal directly into predominently gaseous to liquid products suitable for making hydrocarbon fuel by digesting the coal in a particulate condition at elevated pressure and temperature under hydrogenation conditions, slurried in a solvent or pasting oil for coal wherein the solvent or pasting oil includes recycled heavy bottoms fraction and a recycled lower boiling fraction ... .
(There) is considerable incentive to develop a coal conversion process that would successfully compete with petroleum as a source of conventional distillate fuels. A prime prerequisite for lowering the cost of coal hydrogenation, or more accurately, hydrocracking, is a relatively low pressure process in which hydrocracking would proceed rapidly enough to yield distillable liquid hydrocarbons as the main product.
(Processes) being developed by the Gulf Research and Development Company to produce distillates from coal slurries make use of fixed catalyst beds.
Summary: The present invention relates to a process for converting coal directly into predominantly gaseous to liquid products suitable for making hydrocarbon fuel by digesting the coal in a particulate, more particularly comminuted condition at elevated pressure and temperature ... slurried in a solvent or pasting oil for coal, and wherein the solvent or pasting oil includes recycled heavy bottoms fraction and a recycled lower boiling fraction.
Preferred embodiments of the present invention are directed to processes, capable of converting substantially all the liquefiable coal components to distillate products ... ."
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The full Disclosure makes note that, if desired, some gaseous hydrocarbons can be produced in addition to the "distillate products".
Moreover, it fully explains that the "solvent or pasting oil for coal" needed to form the initial Coal slurry, is "recycled" from within the process itself.
We must note that the full Disclosure does specify the potential for using free Hydrogen to facilitate a more complete hydrogenation of the Coal liquids.
But, we also remind you that multiple technologies exist for the economical generation of such free Hydrogen, most of them developed by the petroleum industry, since "heavy" conventional crude petroleum and some petroleum refinery residues require similar treatment.
In any case, we have, as herein, known officially for very nearly three decades that essentially 100% of the Carbon content of Coal can be converted into hydrocarbon products traditionally derived from petroleum.