United States Patent: 4443321
Yes, the National Aeronautics and Space Administration, perhaps concerned about potential shortages of rocket fuel, has developed their own technology for converting Coal into liquid hydrocarbons.
A close read reveals some, perhaps, surprising facts; and, a close read is demanded to understand exactly what NASA is doing, and what the implications might be.
In sum, they have developed a "gas phase" solvent extraction process for Coal that enables what would seem to be an industrially efficient first extraction, and conversion into hydrocarbons, of up to 50% of the initial Carbon content in Coal.
Aside from the fact that 50% of the Carbon is left behind, which we wi'll address following our full excerpts, there are efficiencies which arise from the fact that raw Coal doesn't have to be highly cleaned, or specifically sized, in order to be processed in NASA's technology.
"The process of the invention is capable of dissolving fairly large lumps of coal and it is not believed to be necessary to subdivide and classify the coal below about 5 mesh before processing in accordance with the invention."
Additional efficiencies are achieved through the fact that the initial Coal extraction, or dissolution, is carried out by a solvent, a blend of various components, that works at elevated pressures; and, thus, enables a straightforward procedure - the simple release of pressure - for recovering the dissolved hydrocarbons, and recovering them in forms that can be directly processed into standard petroleum-type fuels.
Another advance excerpt highlights that potential:
"(A) a highly dense gas which acts like a liquid solvent and efficiently extracts soluble components from coal can be made. Near the critical temperature the dense gas solvent can expand and contract with the involvement of very little energy. On expansion the dense gas loses its solvent properties, rendering it very easy and economical to separate solute from the dense solvent gas ... (and, such) ... coal extract has a very low ash content and can have significantly reduced sulfur content and is suitable for direct conversion into lower viscosity liquid fuel products such as synthetic gasoline ... ."
And, even more efficiencies are realized through the use of products and compounds readily obtained from Coal, as components of the variable solvent "blends", for want of a better term, which effect the initial solvent extraction. Those compounds include the primary Coal oils anthracene and phenanthene; but, of perhaps more interest, since elevated pressures are employed, sulfur dioxide and carbon dioxide can be also be used as components of those Coal extraction solvents, under what are referred to as "supercritical" conditions of temperature and pressure.
Additional comment follows more complete excerpts from:
"United States Patent 4,443,321 - Supercritical Solvent Coal Extraction
Date: April, 1984
Inventor: Leslie Compton, CA
Assignee: The USA, as represented by the Administrator of NASA
Abstract: Yields of soluble organic extract are increased up to about 50% by the supercritical extraction of particulate coal at a temperature below the polymerization temperature for coal extract fragments (450.degree. C.) and a pressure from 500 psig to 5,000 psig by the conjoint use of a solvent mixture containing a low volatility, high critical temperature coal dissolution catalyst such as phenanthrene and a high volatility, low critical temperature solvent such as toluene.
The invention described herein was made in the performance of work under a NASA contract and is subject to the provisions of Section 305 of the National Aeronautics and Space Act of 1958, public law 83-568 (72 Statute 435; 42 U.S.C. 2454).
Claims: A method of separating an organic extract from an inorganics-containing coal (which comprises):
(A)dding to a closed reactor particulate coal and a mixture of solvents consisting of a first and second solvent ... ; said first solvent ... consisting of at least one low volatility, bent ring, polycyclic, aromatic organic compound ... and the second solvent consisting of a higher volatility organic or inorganic compound (and)
heating the reactor to a temperature above 250 C and below 450 C and within 200 C above or below the critical temperature of the solvent mixture at a pressure from 500 to 5,000 psig to form a dense gas phase;
(E)xtracting organic coal components into the dense gas phase; and ... removing said phase from the reactor.
A method ... in which the first solvent is anthracene oil.
A method ... in which the first solvent is ... phenanthrene ... .
A method ... in which the second solvent comprises sulfur dioxide.
A method ... in which the second solvent is one or more solvents selected from heterocyclic and/or monocylic aromatic compounds, ... water, carbon dioxide, carbon monoxide, ammonia, nitrous oxide, carbonyl sulfide and carbon disulfide.
Field and Background: The present invention relates to the extraction of coal and, more particularly, to the solvent extraction of coal under supercritical conditions.
Extraction of the organic matter in coal with near or supercritical solvents is another possible way to perform the upgrading of coal into an inorganic-free, organic extract. Near the critical temperature, a highly dense gas which acts like a liquid solvent and efficiently extracts soluble components from coal can be made. Near the critical temperature the dense gas solvent can expand and contract with the involvement of very little energy. On expansion the dense gas loses its solvent properties, rendering it very easy and economical to separate solute from the dense solvent gas. Separation of the dense gas from the coal followed by expansion to release the solute is much easier than separating solvent liquid from a solid and a solute, as must be done in conventional solvent processes.
Disclosure: A supercritical solvent extraction technique has been developed in accordance with the invention which separates at least 40% of the organic matter in some coals into a substantially inorganic-free hydrocarbon extract. The coal is volatilized into a supercritical gas mixture comprised of a coal dissolution catalyst solvent, such as phenanthrene, having a high critical temperature (Tc) and a low volatility mixed with a second solvent having a critical temperature at least 100.degree. C. lower than the catalyst solvent, such as toluene. The presence of the lower Tc solvent creates a lower Tc mixture and permits extraction of the coal solute at a temperature sufficiently low to avoid coal gasification and polymerization or cross-linking reactions such that the yields are generally about 30 to 50%, and in some cases yields over 50 weight percent of the organic matter in the coal have been achieved.
The coal extract has a very low ash content and can have significantly reduced sulfur content and is suitable for direct conversion into lower viscosity liquid fuel products such as synthetic gasoline.
The gas phase catalyst and coal extract can readily be recovered by expansion, and the catalyst can be recovered from the coal extract by fractional distillation."
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There is a lot more to it, of course, as study of the full document will reveal.
However, what NASA describes is a not-overly complex, and fairly straightforward, industrial process; one which could be easily understood and accomplished by those schooled in what we would think to be standard chemical and industrial engineering.
In other words, though from NASA, it ain't rocket science.
Further, as noted, their process recovers and converts around 50% of the Carbon content in raw Coal.
We submit that - as in other direct solvent extraction, and even indirect, Coal conversion processes we have recorded for you, wherein the fact was demonstrated - the carbonaceous residue resulting from NASA's solvent extraction of Coal could be further processed, we submit and suggest through a process of catalyzed Steam gasification, to extract even more of the Carbon through synthesis of hydrocarbon gases, as has been thoroughly demonstrated and reduced to practice in many places throughout the past century; all, again, as we have several times documented.
Moreover, NASA's straightforward process for generating "coal extract" with "a very low ash content and ... significantly reduced sulfur content" that is "suitable for direct conversion into lower viscosity liquid fuel products such as synthetic gasoline" could well-represent a very economical, lower-cost method of Coal conversion that, if coupled with a, perhaps, higher-cost Steam gasification-conversion process for the carbonaceous residues, could result in a complete system that converted nearly 100% of Coal's carbon content into various, higher-value liquid and gaseous hydrocarbons at an acceptable, even competitive, total aggregate cost.
Such speculations aside: Herein, just as NASA has shown us, as documented in the West Virginia Coal Association's R&D Blog, that we can make liquid fuel out of Carbon Dioxide, on the planet Mars, they have also shown us that we can make liquid fuel out of Coal, right here on the planet Earth.