We've presented numerous reports documenting the development of practical Coal liquefaction technologies by the United States Petroleum industry.
The companies that finally coalesced into that lovable giant, ExxonMobil, especially, established for themselves a significant body of technology that would seem to enable their switching from crude Oil to Coal as their basic feedstock for making liquid fuels pretty much any time it might please them to do so.
What we've found to be especially intriguing as we've driven entries out into the vast bed of Coal conversion science, is the fact that, once you're able to decipher some of the Oil industry's own techno-jargon, the processes which would enable us to start converting our vast reserves of Coal into standard, marketable liquid hydrocarbon transportation fuels are, for the most part, not that much different from the processes needed to transform crude Petroleum, especially "heavy" crude Petroleum, into those liquid hydrocarbon transportation fuels.
By way of example, we submit herein another US-patented technology developed by the old Exxon Research and Engineering Company, in New Jersey, during the late 1970's, a time during which, as we've previously documented, for just one example, as in the report we mislabeled as:
Exxon 1997 Coal Liquefaction Residue Steam-Gasification | Research & Development; concerning: "United States Patent 4,060,478 - Coal Liquefaction Bottoms Conversion by Gasification; Date: November, 1977; Assignee: Exxon Research and Engineering Company, NJ; 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";
Exxon's established science for converting Coal into liquid hydrocarbons was getting so advanced that they had developed practical techniques for recovering Carbon values from any residue that might be excreted from an initial and primary process of Coal hydrogenation.
And, in this submission, we present one of those Exxon primary Coal conversion processes, which just might have led to the co-production of the "Bottoms" their process of the above "US Patent 4,060,478" was designed to convert, through Steam-gasification, into hydrocarbon synthesis gas.
Notable, from our point of view, is the fact, that, at the heart of it, the disclosed processes, as we intimated above, aren't really that much different from those that might be applied to various sorts of crude petroleum.
It is, in other words, stuff they already knew, with relatively minor tweaking, how to do.
As we attempt to point out, in one or two comments, inserted in our excerpts from the initial link to:
"United States Patent 4,045,328 - Production of Hydrogenated Coal Liquids
Date: August, 1977
Inventors: Robert Green and Robert DuBell, NJ
Assignee: Exxon Research and Engineering Company, NJ
Abstract: In a coal liquefaction process wherein feed coal is contacted with molecular hydrogen and hydrogen-donor solvent in a liquefaction zone to form coal liquids and vapors and coal liquids in the solvent boiling range are thereafter hydrogenated to produce recycle solvent and liquid products, the improvement which comprises separating the effluent from the liquefaction zone into a hot vapor stream and a liquid stream, combining a portion of the hot vapor stream with makeup hydrogen and with coal liquids in the solvent boiling range, passing the combined vapor, hydrogen and coal liquids to the solvent hydrogenation zone as feed to the hydrogenation zone, discharging the remainder of the vapor stream as purge after cooling to recover vaporized hydrocarbons and removing contaminants, and thereafter catalytically hydrogenating the hydrogenation zone feed stream while quenching the hydrogenation reaction with fluids recovered from the hydrogenation zone effluent.
(We interrupt here at some length to introduce a reference piece that might well be enlightening to the more technically inclined among our audience, who might not mind doing a little reading. We will, as we go along herein refer back to it once or twice.
Via the complex link:
you can access the textbook:
"Fundamentals of Petroleum Refining; made available by: PDHengineer.com; Houston, TX".
If you even just skim through it, and keep in mind - -
as can be learned from many sources, as, for just one example, in:
American Experience | The Rockefellers | People & Events; wherein we we're told, in part, as in:
"The technology for refining oil was also known by the early 1850s. Doctor Abraham Gesner, a Canadian, in August 1846 patented a method for distilling kerosene (a name he invented from the Greek "keros" -- wax -- and "elaion" -- oil) from coal. (And, in) 1852 two Boston chemists, Luther and William Atwood, began making lubricants from coal tar. Finally, in 1856, Samuel Downer, a whale-oil merchant, bought out the Atwoods and boosted production to 650,000 gallons of refined oil a year. By 1861 coal-oil lamps were widespread and coal-oil was even made in Cleveland";
- - that: We have known how to make crude Oil from Coal since before the American Civil War;
And: since, as a full read of the above article will suggest, some more "modern" Petroleum refining techniques were actually based on earlier technologies for producing and treating Coal Oil, perhaps you can begin to appreciate that some modern petroleum refining techniques, techniques that are profitably practiced everyday in many places around the world, can be applied to the conversion of our abundant Coal into liquid hydrocarbon transportation fuels;
then: it's not too much of a stretch to infer that the modern petroleum industry actually had its roots in an earlier industry founded on the production of liquid fuels, such as kerosene, and lubricants, from Coal.)
Claims: A process for the production of liquid hydrocarbons from coal or similar liquefiable carbonaceous solids which comprises contacting said carbonaceous solids with a hydrogen-donor solvent and molecular hydrogen under liquefaction conditions in a liquefaction zone to produce a liquefaction effluent; separating said liquefaction effluent into a hot vapor stream and a liquid stream; recovering coal liquids in the hydrogen-donor solvent boiling range from said liquid stream; combining a portion of said hot vapor stream with makeup hydrogen and with said coal liquids to form a solvent hydrogenation feed stream; treating the remainder of said hot vapor stream for the removal of liquid hydrocarbons and contaminants and thereafter discharging the remaining gas as purge; passing said solvent hydrogenation feed stream to a catalytic solvent hydrogenation zone maintained under solvent hydrogenation conditions; recovering a hydrogenated effluent from said solvent hydrogenation zone; separating said hydrogenated effluent into a vaporous fraction containing molecular hydrogen and a liquids fraction; recycling at least a portion of said vaporous fraction including molecular hydrogen and at least a portion of said liquidsfraction to said liquefaction zone; and recycling fluid separated from said hydrogenated effluent to said solvent hydrogenation zone as a quench.
(Note: Referring back to "Fundamentals of Petroleum Refining", you will find within it descriptions of "quench" processes, with one explaining, that:
"Hydro-cracking reactors contain multiple beds to enable quenching with cool hydrogen between the beds to prevent uncontrolled ‘temperature runaways” which could result in catastrophic equipment failure."
And, which confirms through implication a few things we have previously documented for you in other reports:
Some reactions in Carbon-Hydrocarbon conversion processes are exothermic; they generate heat energy which can be utilized in other, needed, endothermic reactions forward.
And, one of those reactions could involve the actual "hydro-cracking" of raw liquids, wherein free Hydrogen is added to the complex hydrocarbon molecules - which further implies that free Hydrogen is needed in conventional Oil refineries, and, that economic ways of obtaining that free Hydrogen are available.)
A process ... wherein said liquids fractions separated from said hydrogenated effluent is fractioned to produce light ends, intermediate boiling range hydrocarbons, and a bottoms fraction; said intermediate boiling range hydrocarbons are in part recycled to said liquefaction zone and in part withdrawn as product; and said bottoms fraction is at least in part recycled to said solvent hydrogenation zone as said quench."
(So, some of the "bottoms", or residues, are still suitable for further reaction with Hydrogen, and subsequent processing. The remainder of the residues, we submit, might be suitable for passing on into another process, such as that described in our above reference to "United States Patent 4,060,478 - Coal Liquefaction Bottoms Conversion by Gasification", for reaction with Steam and subsequent conversion of any residual Carbon into hydrocarbon synthesis gas, i.e., a blend of Carbon Monoxide and Hydrogen itself suitable for catalytic condensation, as via the Fischer-Tropsch, or related, process, into liquid hydrocarbons.)
Background and Field: This invention relates to coal liquefaction and is particularly concerned with integrated liquefaction processes in which coal liquids produced by the treatment of feed coal with molecular hydrogen and a hydrogen-donor solvent are subsequently hydrogenated for the production of recycle solvent and additional liquid products.
Among the more promising processes for the production of liquid hydrocarbons from coal are those in which the feed coal is first contacted with molecular hydrogen and a hydrogen-donor solvent in a liquefaction zone at elevated temperature and pressure and a portion of the liquid product is then catalytically hydrogenated in a solvent hydrogenation zone to generate solvent for recycle to the liquefaction step and produce additional liquid products.
Summary: This invention provides an improved process for the preparation of liquid products from coal or similar liquefiable carbonaceous solids which at least in part alleviates the (earlier) difficulties (cited in the full Disclosure) and has advantages over liquefaction processes proposed in the past.
In accordance with the invention, it has now been found that hydrogenated liquid products can be produced from bituminous coal, subbituminous coal, lignite and similar feed materials by first treating the coal or other solid feed material at elevated temperature and pressure with molecular hydrogen and a hydrogen-donor solvent in a non-catalytic liquefaction zone, separating the overhead effluent from the liquefaction zone into a hot vapor stream and a liquid stream, combining a portion of the hot vapor with makeup hydrogen and liquid in the solvent boiling range, passing the combined vapor, hydrogen and liquid to the solvent hydrogenation zone, and discharging the remainder of the vapor stream as purge after the recovery of vaporized hydrocarbons and the removal of contaminants such as ammonia, hydrogen chloride, hydrogen sulfide, and carbon dioxide.
The process of this invention makes efficient use of the heat in both the effluent from the liquefaction zone and that from the solvent hydrogenation zone, eliminates the necessity for multiple high pressure purge streams, permits purging at a lower rate than might otherwise be required, reduces the amount of makeup hydrogen needed, alleviates difficulties that may otherwise be encountered as a result of the non-uniform hydrogenation of coal liquids produced in the liquefaction zone, reduces the likelihood of hydro-cracking and other undesired reactions in the hydrogenation zone, simplifies control of the process, results in greater process flexibility, is less expensive than earlier processes, and has other advantages over liquefaction processes proposed in the past."
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We'll end our excerpts there, but, in doing so, we'll also address the removed "contaminants such as ammonia, hydrogen chloride, hydrogen sulfide, and carbon dioxide".
First, "hydrogen chloride" is simply "hydrochloric acid", a commodity chemical product with many uses and a large market. Although it would have to be sold cheap, it could still easily be sold.
Second, "hydrogen sulfide", if co-produced in sufficient quantity, also has industrial uses. One of its potential uses could be in a process such as that described in our earlier report of:
Exxon Methane and Hydrogen from H2S and Carbon Monoxide | Research & Development; concerning: "United States Patent 4,517,171 - Synthesis of H2 and CH4 from H2S and CO; 1985; Assignee: Exxon Research and Engineering Company, NJ; Abstract: Hydrogen and methane are synthesized from a gaseous feed comprising a mixture of H2S and CO";
wherein we can make both Methane and, perhaps, some of the Hydrogen needed by our subject process of
"United States Patent 4,045,328", to hydrogenate Coal liquids; and, Methane, which we'll presume everyone to recognize and understand the value of.
And, the "CO", the Carbon Monoxide, required by Exxon's "United States Patent 4,517,171" process, to utilize the byproduct Hydrogen Sulfide of Exxon's "United States Patent 4,045,328" process, could itself be made from the "carbon dioxide" byproduct of that "4,045,328" process, by, as seen, for just one example, in:
Bayer Improves Coal + CO2 = Carbon Monoxide | Research & Development; concerning: "United States Patent 7,473,286 - Carbon Monoxide Generator; 2009; Bayer Material Science, AG, Germany; Abstract and Claims: A generator ... for the reaction of carbon-containing raw materials and also to an improved process for the production of carbon monoxide gas. Carbon monoxide gas is ... produced ... by means of a continuous process in which carbon-containing raw materials are reacted with oxygen and carbon dioxide";
reacting that byproduct Carbon Dioxide with some of our favorite "carbon-containing raw material": Coal.