United States Patent: 4189371

We've presented many reports concerning what has turned out to be the absolutely vast array pf Coal, and other Carbon resource, conversion technologies developed by the precedent and consequent corporate embodiments of what was once the symbolic exemplar of American Big Oil: Exxon.

And, perhaps too harshly, we've often criticized, and implied nefarious intent behind, the fact that Exxon obviously invested a great deal of money, over the course of multiple decades, on the development of advanced Carbon utilization technologies, but has spent no money at all either on educating the United States general public about their rather astonishing achievements in Coal and Carbon conversion science, or, on reducing those technical achievements to a commercial practice that would be of immense benefit to the United States domestic economy.

Our own rather significant personal impairments and limitations simply do not allow us to compile and present, in an organized and comprehensible way, a full narrative account of Exxon's rather long, and ongoing, campaign to establish what should by now have become the technological basis for sustainable American liquid fuel independence.

But, herein, after rummaging around a bit in the overstuffed electronic basement into which we shovel our reference files, down a sort of metaphorical Coal chute, we wanted to present a snapshot, as it were, of what Exxon, fully three decades ago, had, in a methodical and thorough way, accomplished in our favored field of Coal conversion science.

Some of what we submit in this dispatch will likely be directly repetitive of reports we've earlier made; and, where we've been able, we note those prior submissions. Some, though, will be new, and, taken as a whole, we think the body of work, which, again, is just a sampled spanning several years, should be motivation enough for all us old Coal miners to start ourselves with our steel-toed boots over the missed opportunities.

Comment, and additional links and excerpts, follow excerpts from the initial link in this dispatch to:

"United States Patent 4,189,371 - Multiple-stage Hydrogen-donor Coal Liquefaction Process

Date: February, 1980

Inventors: Peter Maa and Lonnie Vernon, Texas

Assignee: Exxon Research and Engineering, New Jersey

Abstract: An increased yield of hydrogenated liquid product is obtained from coal by treating the feed coal with a hydrogen-donor solvent and hydrogen-containing gas in a first coal liquefaction reactor to produce a liquefaction effluent; separating the liquefaction effluent into a vaporous stream and a liquid stream, the liquid stream consisting of a low molecular weight liquid fraction and a high molecular weight liquid fraction; removing a sufficient amount of the low molecular weight liquid fraction from the high molecular weight liquid fraction to form a heavy bottoms stream containing less than about 50 weight percent of the low molecular weight liquid fraction based on the weight of the high molecular weight liquid fraction; treating the heavy bottoms stream with additional fresh hydrogen-donor solvent and hydrogen-containing gas in a second coal liquefaction reactor; separating the second liquefaction reactor product into a vaporous fraction and a liquid fraction, and recovering hydrogenated liquid products from the vaporous and liquid fractions. If desired the high molecular weight constituents in the liquid fraction from the second liquefaction reactor may be further treated with fresh hydrogen-donor solvent and hydrogen-containing gas in a third coal liquefaction reactor. Hydrogen-donor solvent may be produced in the process by catalytically hydrogenating at least a portion of the liquid product from each liquefaction reactor, recovering a liquid fraction from the products of the catalytic hydrogenation, and separating a hydrogen-donor solvent from the liquid fraction.

Claims: A multiple-stage hydrogen-donor liquefaction process for producing liquid hydrocarbons from coal.

Preferably, hydrogen-donor solvent is produced in the process by catalytically hydrogenating at least a portion of the liquid product from each liquefaction zone, recovering a liquid fraction from the products of the catalytic hydrogenation and separating the hydrogen-donor solvent from the liquid fraction."

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We are compelled to note that Exxon's technology for the direct liquefaction of Coal, as above, using, as it does, a Hydrogen-donor solvent that itself is made as one function within the total process out of a constituent of the primary Coal liquid extract, sounds closely similar to what we understand of WVU's own "West Virginia Process" for the direct liquefaction of Coal, an inadequate report of which we made in:

WVU Hydrogenates Coal Tar | Research & Development; concerning: "Hydrogenation of Naphthalene and Coal Tar Distillate; Abhijit Bhagavatula; West Virginia University; 2009; Abstract: The hydrogenation of naphthalene and coal-tar distillates. The hydrogenation of coal can be done either directly or indirectly. Direct liquefaction, the direct reaction between coal and hydrogen, involves the conversion of coal to refinable crude hydrocarbons, from which liquid fuels such as gasoline, diesel, kerosene, etc., can be produced."

Further, the multi-step process of Exxon's "US Patent 4,189,371" seems a rather direct evolution of technology they, and their precedent companies, had been establishing for many years, as witness, for one example, our earlier report of:

Esso 1970 CoalTL | Research & Development; concerning: "United States Patent 3,488,279 - Two-stage Conversion of Coal to Liquid Hydrocarbons; 1970; Esso Research and Engineering Company; Abstract: Coal is hydrogenated to produce liquid products in two stages. The first stage is an initial mild conversion by hydrogen-donor extraction followed by a second stage of catalytic hydrogenation using a cobalt molybdate catalyst and added molecular hydrogen. The present invention is directed to the conversion of a solid carbonaceous material such as coal into liquid products (which can be further ) converted into gasoline."

In any case, Exxon's march of Coal liquefaction technology development continued, subsequent to issuance of "United States Patent 4,189,371". And, our United States Government had become intrigued enough by their documented accomplishments to use our tax money to pay for some of it. As seen in:

"United States Patent: 4210518 - Hydrogen-donor Coal Liquefaction Process

Date: July, 1980

Inventors: Edward Wilson and Willard Mitchell, Texas

Assignee: Exxon Research and Engineering Company, NJ

Abstract: Improved liquid yields are obtained during the hydrogen-donor solvent liquefaction of coal and similar carbonaceous solids by maintaining a higher concentration of material having hydrogenation catalytic activity in the downstream section of the liquefaction reactor system than in the upstream section of the system.

Government Interests: The Government of the United States of America has rights in this invention pursuant to Contract No. E(49-18)-2353 awarded by the U.S. Energy Research and Development Administration.

Claims: A hydrogen-donor liquefaction process for converting coal or similar carbonaceous solids into lower molecular weight liquid hydrocarbons.

Background: Hydrogen-donor solvent processes are among the most promising methods for the production of liquid hydrocarbons from coal ... .

In processes of this type, the coal ... is contacted with molecular hydrogen and a hydrogen-donor solvent at elevated temperature and pressure in a liquefaction zone. The effluent from the liquefaction zone is processed for the recovery of gases and vapors, liquid hydrocarbon in the solvent boiling range, and heavier constituents including a bottoms fraction containing suspended particles of unreacted coal, mineral matter and other solid residues. The solvent boiling range materials are further treated in a catalytic solvent hydrogenation zone to generate hydrogen-donor solvent for recycle to the liquefaction zone and produce additional liquid products."

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The above exposition of "United States Patent 4,210,518" is, of course, in addition to it's demonstration of the obvious depth of understanding of Coal conversion technology that existed in the petroleum industry, further confirmation that our United States Government was not only, through the Patent and Trademark Office, fully aware of it, but, through the "U.S. Energy Research and Development Administration", willing to pay Big Oil with our money to develop and improve it.

And, Exxon was so encouraged that they went on to improve their multi-stage direct liquefaction processes, by shortly thereafter adding on even additional steps, to ensure that all of the Coals original content of Carbon was extracted and utilized, as seen in:

"United States Patent: 4252633 - Coal Liquefaction Process

Date: February, 1981

Inventors: Robert Long, et. al., NJ

Assignee: Exxon Research and Engineering Company, NJ

Abstract: An integrated coal pretreatment, liquefaction and gasification process is provided in which particulate coal is contacted with a vapor phase hydrogen donor solvent to swell the coal particles. The swollen coal particles are subjected to coal liquefaction conditions at relatively low temperatures. The solid residue of the coal liquefaction stage is subjected to pyrolysis conditions at relatively high temperatures to produce an additional amount of hydrocarbonaceous oil. The solid residue of the pyrolysis stage is gasified by treatment with steam and a molecular oxygen-containing gas to produce a hydrogen-containing gas."

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The full Disclosure of "United States Patent 4,252,633" is so involved that we're compelled to cut the excerpts very short, and to offer a synopsis of what's transpiring within it:

First, Coal is being liquefied, or extracted, and hydrogenated with a Hydrogen-donor solvent, as might be accomplished in the precedent process above of "United States Patent 4,210,518".

However, if the initial direct liquefaction is conducted under "mild" conditions, that is, under lower pressure and lower temperature, and, thus, with lower expense; and, in only a less-expensive single stage; not all of the Coal's original content of Carbon will be extracted and hydrogenated.

More of that residual Carbon, remaining after a direct solvent extraction, can then be extracted from the solid residues by a straightforward process of Coal pyrolysis, a high-temperature partial oxidation similar to a coking process, and similar to other Coal conversion technologies about which we've previously reported, and some of which, as with Exxon's above-cited process of "United States Patent 4,210,518 - Hydrogen-donor Coal Liquefaction Process", were developed by research paid for by our tax money, as seen in:

Pittsburgh USBM Recycles CoalTL Residue | Research & Development; concerning: "United States Patent 2,634,286 - Hydrocarbon Synthesis Gas from Coal; 1953; Inventors: Martin Elliott, et. al., Pittsburgh, PA;  Assignee: The United States of America; Abstract: This invention relates to the production of synthesis gas and more particularly to the production of a low-sulfur content mixture of carbon monoxide and hydrogen by gasifying the char obtained as a byproduct of the direct hydrogenation of coal.The low-sulfur content synthesis gas produced by gasification of this low-sulfur content char will find one of it's most advantageous uses in processes such as the Fischer-Tropsch ... to form liquid and gaseous hydrocarbons."

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And, the immediately above explains why we would be going to the trouble of gasifying the direct Coal liquefaction residues, to, as Exxon's process of "United States Patent 4,210,518" stipulates, make such "a hydrogen-containing gas" in the first place, i.e., "to form liquid and gaseous hydrocarbons".

Exxon's march of Coal conversion progress continued, of course, as evidenced by, from the same year:

"United States Patent: 4283267 - Staged Temperature Hydrogen-donor Coal Liquefaction Process

Date: August, 1981

Inventors: Peter Maa and Lonnie Vernon, Texas

Assignee: Exxon Research and Engineering Company, NJ

Abstract: An increased yield of hydrogenated liquid product is obtained from coal by contacting the feed coal with a hydrogen-donor solvent and a hydrogen-containing gas in a series of two or more liquefaction zones arranged in series and operated in such a manner that the temperature in each zone increases from the initial to the final zone. The effluent from each liquefaction zone is passed to the next succeeding higher temperature zone in the series. Liquid hydrocarbonaceous products are recovered from the effluent withdrawn from the last zone. Hydrogen-donor solvent may be produced in the process by catalytically hydrogenating at least a portion of the liquid product from the last liquefaction zone, recovering a liquid fraction from the product of the catalytic hydrogenation and separating a hydrogen-donor solvent from the liquid fraction.

Claims: A hydrogen-donor liquefaction process for converting coal ... into lower molecular weight liquid hydrocarbons which comprises ... contacting said carbonaceous solids with a hydrogen-donor solvent in the absence of an added hydrogenation catalyst under liquefaction conditions in a plurality of liquefaction zones arranged in series and operated such that ... the temperature in each zone increases from the initial to the final zone.

The present invention provides an improved process for converting coal or similar liquefiable carbonaceous solids into lower molecular weight liquid hydrocarbons that at least in part alleviates the difficulties described (in provided examples of prior art). In accordance with the invention, it has now been found that an increased yield of hydrogenated liquid products is obtained from bituminous coal, subbituminous coal, lignite or a similar carbonaceous feed material by contacting the feed solids with a hydrogen-donor solvent under liquefaction conditions in a plurality of liquefaction zones arranged in series and operated such that the temperature in each zone increases from the initial to the final zone of the series.

It will be apparent from the preceding discussion that the invention provides an improved process for converting coal into a hydrogenated liquid product. The process results in an increased yield of hydrogenated liquid product with a resultant decrease in the amount of high molecular weight bottoms produced."

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We've previously documented the co-production of, as above, "high molecular weight bottoms", which are still-carbonaceous residues, whether liquid or solid, that are generated by both, as herein, direct, and, indirect, Coal conversion processes.

And, as seen above, via our excerpts from "United States Patent 4,252,633 - Coal Liquefaction Process", wherein it's explained that "solid residue of the coal liquefaction stage is subjected to pyrolysis conditions at relatively high temperatures to produce an additional amount of hydrocarbonaceous oil. The solid residue of the pyrolysis stage is gasified by treatment with steam and a molecular oxygen-containing gas to produce a hydrogen-containing gas";

As we will further document, productive options do exist for the further productive conversion of such "bottoms", no matter what type of Coal conversion process might generate them, and Exxon has their own ways of dealing with them. We'll get to that, but, following, is more of the methodical Coal conversion trail blazed by Exxon in subsequent years, as in:

"United States Patent: 4338182 - Multiple-stage Hydrogen-donor Coal Liquefaction

Date: July, 1982

Inventors: Lonnie Vernon and Peter Maa, Texas

Assignee: Exxon Research and Engineering Company, New Jersey

Abstract: An improved process for liquefying coal and similar solid carbonaceous materials wherein the liquefaction is accomplished in a plurality of zones or stages and wherein the temperature is increased either linearly or nonlinearly in the first zone or stage, aromatics which are produced, liberated or contained in the solvent are separated after the first zone or stage and the liquefaction is continued in at least one other stage, at a temperature at least as high as the final temperature in the first zone or stage. In a preferred embodiment, the temperature in the first stage will be increased at least 50F. The improved process results in a higher conversion of carbon contained in the coal ... to liquid products.

Claims: A process for liquefying normally solid carbonaceous materials ... .

Background and Field: This invention relates to an improved process for converting coal or similar solid carbonaceous materials. More particularly, this invention relates to an improved process for liquefying coal and similar carbonaceous substances.

To this end, several processes wherein coal is either liquefied and/or gasified have been proposed heretofore. Of these, the processes wherein coal is liquefied appear to be more desirable since a broader range of products is produced and these products are more readily transported and stored. 

Of these several liquefaction processes which have been heretofore proposed, those processes wherein coal is liquefied in the presence of a solvent or diluent, particularly a hydrogen-donor solvent or diluent, and a hydrogen containing gas appear to offer the greater advantages. In these processes, liquefaction is accomplished at elevated temperatures and pressures and hydrocarbon gases are invariably produced as byproducts. Moreover, none of the prior art processes have resulted in complete conversion of the coal or similar solid carbonaceous materials. As a result, a normally solid residue containing ash and unconverted coal is also invariably obtained. The gaseous products and/or the residue can be further processed to provide process hydrogen or can be burned to produce process energy. The quantity of gaseous products and unconverted coal, however, generally exceeds the quantity required for an overall energy and hydrogen balance. Moreover, the cost of recovering hydrogen and/or the heating value of the unconverted coal remaining in the residue is generally excessive. The need, therefore, for a liquefaction process which will maximize coal conversion thereby minimizing unconverted coal in the residue, is believed to be readily apparent. Moreover, the need for such a liquefaction process resulting in reduced gas yields is also believed to be apparent.

It is, therefore, an object of this invention to provide an improved liquefaction process. It is still another object of this invention to provide such a liquefaction process wherein the unconverted coal remaining in the residue is reduced. It is still a further object of this invention to provide such an improved liquefaction process wherein the gas yields are reduced. It is yet another object of this invention to provide such an improved liquefaction process wherein the liquid yields are increased.

The method of this invention is particularly useful in the liquefaction of coal and may be used to liquefy any of the coals known in the prior art including anthracite, bituminous coal, subbituminous coal, lignite, peat, brown coal and the like.

(It) is believed readily apparent that significant increases in liquefaction yields can be achieved by combining staged-temperature liquefaction; that is, liquefaction wherein the temperature is increased from start to finish during the liquefaction, and staged solvent liquefaction; that is, liquefaction wherein solid material is effectively separated between liquefaction stages and subjected to further liquefaction. The really surprising aspect of this discovery is, in effect, that the benefits associated with staged-temperature liquefaction and staged solvent liquefaction are additive and that when these two modes of operation are combined from about 50 to about 90 weight percent of the initially available carbon can be recovered either as a gaseous product or as a liquid product. Moreover, it is believed readily apparent from the foregoing examples that the increased carbon conversion is primarily due to conversion to liquid products since the gas product yield either remains the same or reduces as a result of the combination."

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We note that our overly-long excerpts from "United States Patent 4,338,182" focus more on the descriptive exposition than on the technical aspects. Those who are technically qualified genuinely interested can glean those aspects from the full document maintained, via the link, by our Government.

Note that both liquid and gaseous hydrocarbons are produced, the values of which should be obvious, and which we won't dwell on, as well as, still, some solid carbonaceous residue, which could contain as little as 10%, and up to 50%, of the initial Carbon content of the Coal.

And, we'll note that the process of "United States Patent 4,338,182" was closely related to, and perhaps to a certain extent precedent of, the Coal conversion process disclosed by a slightly later US Patent awarded to the same team of Exxon scientists, and about which we earlier reported in:

Exxon 1982 CoalTL Uses WVU CoalTL Hydrogen Donor Solvent | Research & Development; concerning: "United States Patent 4,345,989 - Catalytic Hydrogen-donor Liquefaction Process; August, 1982; Lonnie Vernon, et. al.; Assignee: Exxon Research and Engineering Company; Abstract: Coal or a similar solid carbonaceous feed material is converted into lower molecular weight liquid hydrocarbons by contacting the feed material with a hydrogen-donor solvent containing above about 0.6 weight percent donatable hydrogen and molecular hydrogen in a liquefaction zone or a series of two or more liquefaction zones ... in the presence of an added carbon-alkali metal catalyst ... . Claims: A catalytic hydrogen-donor liquefaction process for converting a solid carbonaceous feed material into lower molecular weight liquid hydrocarbons which comprises contacting said feed material with a hydrogen-donor solvent".

And, we note again that the Hydrogen-donor solvent, or solvents, described by Exxon in "United States Patent 4,345, 989", appear to be the same as those described, as above, in our citation of "Hydrogenation of Naphthalene and Coal Tar Distillate; Abhijit Bhagavatula; West Virginia University; 2009".

But, other Exxon scientists continued to work with the Hydrogen-donor Coal liquefaction process, and discovered that improvements could be had in the conversion of Coal into hydrocarbons if the liquefaction conditions of temperature and pressure were adjusted so that the Hydrogen Donor could act on the Coal in the form of a vapor, as opposed to a liquid.

Such a technology is represented by:

United States Patent: 4385981 - Liquefaction ... with Vapor Phase Hydrogen Donor

Date: May, 1983

Inventors: Daniel Neskora and Richard Schlosberg, NJ

Assignee: Exxon Research and Engineering Company, NJ

Abstract: Disclosed is a method for enhancing the conversion of carbonous materials, such as coal and oil shale. The method comprises converting the carbonous material in the presence of a vapor phase hydrogen donor material containing 1 or more hydrogen donor solvents wherein each donor material is characterized by: (a) a heterocyclic ring in which the heteroatom is nitrogen, (b) having at least one donatable hydrogen located on the heterocyclic ring, and (c) becoming more unsaturated and/or aromatic upon the loss of the donatable hydrogen(s). The conversion is performed at substantially atmospheric pressure, at an effective vapor residence time and at a temperature from about the boiling point of the hydrogen donor material to about 550C.

Claims: A method for enhancing the conversion of carbonous materials to liquids wherein the carbonous material is selected from the group consisting of coal, oil shale, peat and solid products thereof, the method which comprises converting the carbonous material: in the presence of a hydrogen donor material, in the vapor phase ... ; and: at a temperature from about 350C to about 550C.; and: at substantially atmospheric pressure; (and) wherein at least some of the hydrogen donor material is recycle hydrogen donor material obtained from a product stream resulting from the method herein claimed. 

The method ... wherein the carbonous material is coal.

 

By choosing the proper vapor residence time, substantially maximum conversion of carbonous material to liquids and recovery of the hydrogen donor material or its aromatic form in relatively high yields for hydrogenation and recycling is achieved.

It will be noted that other (than as specified in the full Disclosure) conventionally used hydrogen donor materials, which do not meet the requirements set forth above, are unsuitable for use in the practice of the present invention. Such donor materials include tetralin.

(So, unfortunately, the Hydrogen donor specified and utilized by WVU, in their "West Virginia Process" for direct Coal liquefaction, "tetralin", the hydrogenated version of the Coal oil, naphthalene  would not qualify for use in this Exxon Coal conversion process. However, the full Disclosure does specify and describe what we would call "plenty" of other Coal-derived options, most of which, as Exxon fully describes, can be produced in and extracted from the process itself.)

Generally, any type of coal, peat, oil shale or products thereof which are normally solid at room temperature may be utilized in the practice of the present invention. When coal is utilized, liquid yields from bituminous, subbituminous and lignite will be particularly enhanced."

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So, by contacting Coal with a Hydrogen Donor maintained as a vapor, rather than as a liquid, the "liquid yields from" all sorts and ranks of Coal "will be particularly enhanced".

But, those conditions and stipulations are counterbalanced by the potentials for Carbon use and ranges of products which can be achieved through other Exxon Coal conversion processes, which, employing higher pressures and temperatures, are able to utilize the naphthalene-derived "tetralin".

As seen in an even additional and subsequent Exxon-developed process, the full Disclosure of which we highly recommend for study by those truly interested in the flat-out truth that we, or at least Exxon and our United States Government, know precisely and thoroughly how to go about converting Coal and renewable, Carbon-recycling wastes thoroughly and efficiently into liquid hydrocarbon fuels:

"United States Patent: 4485008 - Liquefaction Process

Date: November, 1984

Inventors: Peter Maa, et. al., Texas

Assignee: Exxon Research and Engineering Company, NJ

Abstract: An improved liquefaction process for solid carbonaceous materials wherein at least a portion of the liquefaction is accomplished in the presence of an added hydrogenation catalyst and a solvent containing at least 1.25 weight % donatable hydrogen and in the presence of partially liquefied, solid carbonaceous material at liquefaction conditions. In a preferred embodiment, the liquefaction is accomplished in a plurality of stages and a solvent containing at least 1.25 weight % donatable hydrogen is used in at least one stage, most preferably in the second stage. The partially liquefied solid carbonaceous material may be taken from the bottoms fraction of the effluent from any of the liquefaction stages.

(We note, that, even though the "partially liquefied, solid carbonaceous material" which is required for the initial processing of the "solid carbonaceous materials" can "be taken from the bottoms fraction of the effluent from any of the liquefaction stages", it begs the question as to where such material might come from to actually initiate or start up the process in the first place. As can be documented in other, related, patented technologies concerning the co-liquefaction of Coal and petroleum refinery residues, "resids", which we don't, our of our Coal-centered prejudices, dwell much upon, we can obtain the needed initial  "partially liquefied, solid carbonaceous material", if no more attractive and palatable options exist, from an oil refinery.)

Claims: A process for the liquefaction of a solid carbonaceous material wherein the solid carbonaceous material is at least partially liquefied in a plurality of stages and in the presence of an added hydrogenation catalyst, which catalyst is present in all stages, wherein a solvent containing at least 1.25 weight % donatable hydrogen is used in the second or subsequent stages while a hydrogen donor solvent containing less than 1.25 weight. % donatable hydrogen is employed in the first stage and wherein the liquefaction is accomplished in the presence of a residue comprising partially liquefied solid carbonaceous material, which residue comprising partially liquefied solid carbonaceous material is separated from the liquefaction product, and at (specified temperatures and pressures) to produce a gaseous product, a liquid product and a normally solid bottoms product.

Background and Summary: This invention relates to an improved process for ... liquefying coal.

As is ... well known, proven petroleum and gas reserves are shrinking throughout the world and the need for alternate sources of energy is becoming more and more apparent. One such alternate source is, of course, coal since coal is an abundant fossil fuel in many countries throughout the world. Before coal will be widely accepted as a fuel, however, it is believed necessary to convert (it) to a form which will ... permit (Coal's) use in those areas where liquid or gaseous fuels are normally required. 

To this end several processes wherein coal is either liquefied and/or gasified have been proposed heretofore. Of these, the processes wherein coal is liquefied appear to be more desirable since a broader range of products is produced and these products are more readily transported and stored. 

Of the several liquefaction processes which have been heretofore proposed, those processes wherein coal is liquefied in the absence of added catalyst and in the presence of a solvent or diluent have been favored over catalytic processes even though the non-catalytic processes do not result in complete conversion of available carbon to either a liquid or gaseous product. One reason for this preference could be the relatively high cost of the catalyst and the cost associated with its recovery and recycle to the liquefaction. Another reason, however, could be that recycled catalyst tends to be rapidly poisoned and deactivated. In either case, the catalytic processes which have been proposed heretofore have not, on a continuous basis, approached stoichiometric conversion of the available carbon and have not been economically attractive when compared to the thermal conversion processes.

 

(Note: By the above "thermal conversion processes", Exxon means, we're fairly certain, indirect Coal conversion processes which involve and initial gasification of the Coal, to form a synthesis gas. And, Exxon notes that "direct" Coal liquefaction technologies, as they are disclosing herein, have not previously "been economically attractive when compared to" such Coal gasification technologies. If you have followed our reports at all, you will know that Coal gasification enables the ultimate synthesis of a broad range of products, and the inclusion of both Carbon-recycling wastes and Carbon Dioxide itself in the Coal gasification process. So, since this Exxon-invented direct Coal liquefaction might have advantages, so do indirect Coal conversion processes, and, there might be room, and need, for them both.)

Since stoichiometric conversion of available carbon would be most desired, however, the need for an improved catalytic process is believed to be readily apparent.

The preferred catalyst compounds or precursors are the oil soluble metal compounds containing a metal selected from the group consisting of molybdenum, vanadium and chromium. More preferably, the metal constituent is selected from the group consisting of molybdenum and chromium. Most preferably, the metal constituent of an oil soluble metal compound is molybdenum.

(Exxon actually identifies a fair number of metals that will get the job done. But, they've settled on molybdenum as the best. Even though it isn't as common as beach sand, it is mined commercially in Colorado, western Canada and Chile; and, there is so much of it that one or two of the developed molybdenum mines are currently idle. If demand warrants, it can also be produced as a by-product from the mining of some other commercial minerals. In other words, we have plenty of it now, and we can economically get more. The discussion indicates and implies that a very great deal of effort was put into the selection and development of the best, most-efficient catalysts.)

In general, the method of the present invention can be used to liquefy any solid carbonaceous material which can be hydrogenated, cracked and liquefied. The method of this invention is particularly useful in the liquefaction of coal, coke, wood and similar solid carbonaceous materials containing a relatively high ratio of carbon to hydrogen. In general, any of the coals known in the prior art including anthracite, bituminous coal, subbituminous coal, lignite, peat, brown coal and the like may be liquefied with the method of this invention.

(Note, that, through the inclusion of "wood and similar solid carbonaceous materials", we can, as with many other, similar and related, Coal conversion technologies, include a portion of sustainable, CO2-recycling raw materials of botanic origin.)

After the liquefaction is completed the gaseous product from each stage may be upgraded to a pipeline gas or the same may be burned to provide energy for the liquefaction process. Alternatively, all or any portion of the gaseous product may be reformed to provide hydrogen for the liquefaction process. 

The liquid products may be fractionated into essentially any desired product distribution and/or a portion thereof may also be used directly as a fuel or upgraded using conventional techniques. Generally, a naphtha boiling range fraction will be recovered and the naphtha fraction will be further processed to yield a high-quality gasoline or similar fuel boiling in the naphtha range."

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And, so, we can efficiently make both "pipeline gas" and "high-quality gasoline" in a process that, while based on Coal, also allows the consumption and use of CO2-recycling and sustainable "wood", and, we must conclude, other cellulose-containing materials such as sewer sludge and the cellular residue that remains after bio-lipids have been extracted for conversion into Gasoline and Diesel from Algae grown in reactors designed to capture and recycle industrial effluent Carbon Dioxide, as explained, for just one example in our earlier report of:

USDOE Algae Recycle CO2 into Liquid Fuels | Research & Development; concerning: "Liquid Fuels from Microalgae; 1987; USDOE; Abstract: The goal of the DOE/SERI Aquatic Species Program is to develop the technology to produce gasoline and diesel fuels from microalgae."

Further, even if the above Exxon technologies don't, somehow, consume and utilize all of the Carbon provided initially to them, in the form of Coal and Carbon-recycling biomass, then Exxon knows how to extract and productively utilize any Carbon that might remain in the direct Coal liquefaction residues, as we documented in:

Exxon 1997 Coal Liquefaction Residue Steam-Gasification | Research & Development; concerning: "United States Patent 4,060,478 - Coal Liquefaction Bottoms Conversion by Gasification; 1977; Assignee: Exxon Research and Engineering Company; Abstract: Heavy bottoms produced by the liquefaction of coal ... are converted into more valuable products by ... (after initially producing) gases, hydrocarbon liquids and ...char, thereafter gasifying the char with steam."

In any case, the essence is this:

For more than a quarter of a century, Big Oil, as personified by Exxon, and our own United States Government, as it is embodied in the US Patent and Trademark Office, have known that we can, efficiently and thoroughly, convert both Coal and some forms of Carbon-recycling biomass into, concurrently, in the same processing facility, both "pipeline gas" and "high-quality gasoline".

And, as noted above in the statement of "Government Interests" in the Disclosure of US Patent 4,210,518; We the People actually paid to have at least some of the technology developed, and supposedly own a share of it.

Why have we not yet started to utilize and profit by that knowledge and that technology?

Why have we, the general public, not yet even been clearly informed that such knowledge and such technology exist?


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