This submission demands some extended preamble, so please bear with us.
First, we remind you that we have documented the founding of a sophisticated and seemingly extensive Coal liquefaction technology base at the University of Utah; an effort that spanned decades.
That effort seems to have been driven by a core team of scientists; with one, in particular, Wendell H. Wiser, apparently leading the charge; and, a large part of that effort was paid for by our USDOE.
Our reports concerning the Utah Coal conversion campaign have included:
West Virginia Coal Association | USDOE Funds Utah Coal Liquefaction Catalyst Improvements | Research & Development; concerning: "United States Patent 4,134,822 - Minimizing ... Catalyst Requirements for Coal Hydrogenation-Liquefaction;
West Virginia Coal Association | USDOE Pays Utah to Liquefy Coal | Research & Development; concerning: "United States Patent 5,308,477 - Method for Coal Liquefaction; 1994; Inventors: Wendell Wiser, et. al.; Assignee: University of Utah; Abstract: A process is disclosed for coal liquefaction in which minute particles of coal in intimate contact with a hydrogenation catalyst and hydrogen are reacted for a very short time at a temperature in excess of 400C. at a pressure of at least 1500 psi to yield over 50% liquids with a liquid to gaseous hydrocarbon ratio in excess of 8:1. This invention was made with Government support under Contract No. DE-AC22-88PC88817 awarded by the Department of Energy. The government has certain rights in the invention"; and:
West Virginia Coal Association | Utah Makes Gasoline from Coal | Research & Development; concerning:
“Production of Gasoline Components (from) Coal-derived Aromatic Hydrocarbons; 2007; B. Demirel and W.H. Wiser; University of Utah; Abstract: The main objective of this work was to convert aromatic compounds, representative of coal-derived liquids, into high octane compounds low in aromatics".
Note, that, as explained better in the full Disclosures of "United States Patent 4,134,822" and "United States Patent 5,308,477", the Utah Coal conversion technologies seem to have been founded on the principles of the Nobel Prize-winning Bergius direct Coal hydrogenation processes, as described, for one example, in:
West Virginia Coal Association | More Nobel Prize-Winning Coal Liquefaction | Research & Development; which centered on: "United States Patent 1,391,664 - Hydrogenating Carbon Compounds Under High Pressure; 1921; Inventor: Friedrich Bergius, Germany; Abstract: This invention is an improvement in the process of hydrogenating, under high pressure and at an elevated temperature, natural coal or other products of carbonization of wood and other vegetable matter (which) are carbonized by the heat of the process. By such process, these carbonaceous materials are transformed into liquids".
We'll digress a bit here to explain that, as has been seen in one or two of our previous reports, such direct hydrogenation processes have been developed and described by a number of others; and, the various terminologies employed could lead to some confusion.
Hydrogen is the simplest of elements, consisting in its atomic structure only of one proton and one electron.
And, in terms of mass, that is, the real meat of the thing, the electron is inconsequential; although, chemically speaking, the sub-atomic electric charge it brings to the game is essential. However, electrons are, or can be made to be, freely available for chemical reactions, and can be considered, in terms of matter transfer, almost non-existent.
An Hydrogen atom stripped of it's electron consists only of a single proton; and, as we have touched on briefly in one or two prior reports, but as we will see in more detail in the future, some Hydrogen transfer, or Hydrogen donation, reactions in Coal hydrogenation technologies are labeled as "Proton Donor" processes.
Further, the single proton represents the Hydrogen ion, "H+", which you will every once in a great while see labeled as "hydronium".
All of that sounds very Three Mile Island nasty; but, don't be misled. Although single protons moving about are involved, it is all straightforward ionic chemistry; and, we don't have to concern ourselves with nuclear physics, i.e., radioactivity.
It is, in fact, all Hydrogen donor chemistry; with the goal being to add Hydrogen to Carbon to synthesize Hydrocarbons.
Hydrogen donor chemistry for Coal hydrogenation is, as they are fond of saying in the patent literature when referring to precedent technology, "well known in the art".
West Virginia University's own "West Virginia Process" for the direct liquefaction of Coal, as alluded to and partially described in our report:
WVU Hydrogenates Coal Tar | Research & Development; concerning: "Hydrogenation of Naphthalene and Coal Tar Distillate over Ni/Mo/Al2O3 Catalyst; Abhijit Bhagavatula; Thesis submitted to the College of Engineering and Mineral Resources at West Virginia University in partial fulfillment of the requirements for the degree of Master of Science in Chemical Engineering. John W. Zondlo, Ph.D., Chair; Elliot B. Kennel, M.S; Alfred H. Stiller, Ph.D; Department of Chemical Engineering; Morgantown, West Virginia. 2009. Abstract: The hydrogenation of naphthalene and coal-tar distillates has been carried out in a Trickle Bed Reactor, in which the liquid is allowed to flow through the catalyst bed in the presence of hydrogen. 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";
is one example, wherein the primary Coal, or Coke Oven, oil, or tar, Naphthalene, is hydrogenated, reacted, with free Hydrogen, and then used as a Hydrogen donor solvent for raw Coal; and, it is founded on much earlier Coal conversion processes, as seen, for example, in:
West Virginia Coal Association | Germany Invents WVU Coal Liquefaction Solvent - in 1926 | Research & Development; concerning: "United States Patent 1,582,310 - Hydrogenation of Naphthalene; 1926; Inventor: Georg Schroeter, Berlin; The present invention relates to the hydrogenation of commercial naphthalene in a technical manner, whereby products can be produced on a technical scale which are suitable for various purposes, such as substitutes for mineral oil distillates, including gasoline".
Further, such Coal oil-based Hydrogen donor technology hasn't escaped the notice of Big Oil, as seen in:
Exxon 1982 CoalTL Uses WVU CoalTL Hydrogen Donor Solvent | Research & Development; concerning: "United States Patent 4,345,989 - Catalytic Hydrogen-donor Liquefaction Process; 1982; Assignee: Exxon Research and Engineering Company; Abstract: Coal ... is converted into lower molecular weight liquid hydrocarbons by contacting the feed material with a hydrogen-donor solvent ... and molecular hydrogen in a liquefaction zone ... in the presence of an added carbon-alkali metal catalyst comprising a carbon-alkali metal reaction product prepared by heating an intimate mixture of carbonaceous solids and an alkali metal constituent to a temperature above about 800 F. in a reaction zone external to the liquefaction zone. The hydrogen-donor solvent ... will normally be a coal-derived solvent, preferably a hydrogenated recycle solvent ... (and) compounds of this type include ... tetrahydronaphthalenes."
In one aspect, chemical acids, such as Hydrochloric Acid, HCl, can also be thought of as Hydrogen donors, since the Hydrogen in their composition is readily available for chemical recombination with other compounds; although the other components of the acid most usually become involved and incorporated in the new compounds, as well.
There is a class of acids, however, about which we have earlier reported, called "super" or "magic" acids, which act, more or less, simply as Hydrogen donors; or, like the "tetrahydronaphthalenes" of Exxon's "United States Patent 4,345,989, perhaps more accurately, since "molecular hydrogen" does have to be available for them to draw from, "Hydrogen transfer agents".
And, such agents can serve to facilitate, and reduce the energy input needed, as exemplified in the more direct and basic "United States Patent 1,391,664 - Hydrogenating Carbon Compounds Under High Pressure", as cited above, to "pick" a Hydrogen atom from some source or another, and "plant", our words, that Hydrogen atom onto a Carbon atom, to form a hydrocarbon molecule.
Another Nobel Laureate, on the faculty of the University of Southern California, described such use of "magic" acids in our report of:
West Virginia Coal Association | California Magic Acid Liquefies Coal | Research & Development; concerning: "United States Patent 4,394,247 - Liquefaction of Coals Using Recyclable Superacid Catalyst; 1983; Inventor: George Olah, Beverly Hills, CA; Abstract: This invention discloses a process for the liquefaction of coals ... by treating the same with a superacidic catalyst system consisting of anhydrous hydrogen fluoride and boron trifluoride in the presence of super-atmospheric hydrogen".
Note, that, as in the 1921 Bergius "United States Patent 1,391,664 - Hydrogenating Carbon Compounds Under High Pressure", pressurized, i.e., "super-atmospheric", Hydrogen does need to be available for the Carbon hydrogenation reaction to proceed.
The difference lies in the fact, that, with a "Superacid Catalyst", the needed pressures, and temperatures, can be much, much lower; thus leading to greatly improved energy and process efficiencies.
Herein, Wendell Wiser and a few of his colleagues at the University of Utah explain a great deal of that more succinctly, as seen in excerpts from the initial link in this dispatch to:
"United States Patent 5,783,065 - Method for Coal Liquefaction
Date: July, 1998
Inventors: Wendell H. Wiser, et. al., Utah
Assignee: University of Utah Research Foundation, Salt Lake City
Abstract: A process is disclosed for coal liquefaction in which minute particles of coal in intimate contact with a hydrogenation catalyst and hydrogen are reacted for a very short time at a temperature in excess of 400C. at a pressure of at least 250 psi to yield over 50% liquids with a liquid to gaseous hydrocarbon ratio in excess of 8:1.
Claims: A method for converting more than 50% by weight coal to liquids wherein a ratio of liquids to hydrocarbon gases in a reaction product is greater than about 8:1, by weight comprising the steps of:
- introducing finely divided particles of coal into a thermal cracking zone having a temperature of at least 400C and a pressure of from about 250 psi to less than about 1500 psi;
- introducing a hydrogenation catalyst in intimate contact with said coal particles into said thermal cracking zone, said catalyst being substantially simultaneously introduced with said coal particles;
- introducing hydrogen into said thermal cracking zone;
- maintaining said coal particles, hydrogenation catalyst, and hydrogen in said thermal cracking zone for a time period sufficiently short to yield a reaction product having a ratio of liquid to gaseous hydrocarbons in said product in excess of 8:1 by weight and a liquid content in excess of 50% of the weight of coal particles introduced into said cracking zone;
The method ... wherein said catalyst is introduced into said cracking zone as a vapor phase catalyst to penetrate into the pores of the coal particles by virtue of being a vapor.
The method ... wherein said catalyst is impregnated into said coal particles prior to introduction into said cracking zone (or) wherein said catalyst is impregnated into said coal particles as a solid-phase catalyst dissolved in a suitable solvent to impregnate the pores of said coal particles to ensure a high dispersion of the catalyst, said solvent then being evaporated.
The method ... wherein said coal particles, catalyst and hydrogen are introduced into a continuous-flow system.
The method ... wherein the catalyst is selected from the group consisting of hydrates of iron-containing salts ... selected form the group consisting of ferric chloride hexahydrate, ferric sulfate pentahydrate, ferric formate and ferrous acetate.
The method ... wherein the catalyst is a highly dispersed solid superacid (and) wherein said superacid is Fe2O3 /SO4-2 or ZrO2 /SO4-2 (or) wherein the catalyst is a volatile metal halide.
(Concerning such use of "a volatile metal halide" in Coal conversion processes, see, for instance, our report:
Consol 1967 Coal Tar to Gasoline | Research & Development; which concerns: "United States Patent 3,355,376 - Hydrocracking of Polynuclear Hydrocarbons; 1967; Assignee: Consolidation Coal Company;
Abstract: Polynuclear aromatic hydrocarbons such as coal extract are hydrogenated in the presence of molten zinc halide catalyst. Claims: (A) process for converting polynuclear aromatic hydrocarbonaceous feedstock to gasoline";
wherein "zinc halide"; which would include Zinc Chloride, a commonly-specified ingredient in patented Coal liquefaction processes, qualifies nicely as just such "a volatile metal halide. There are quite a few others which will serve, including some, such as Hydrogen Fluoride, HF, which you will find named in the full Disclosure of "United States Patent 4,394,247 - Liquefaction of Coals Using Recyclable Superacid Catalyst", as cited above; but, which you wouldn't ordinarily think of as being a "metal halide". And, the University of Utah does go on to specify both Iron Chloride and Tin Chloride as being suitable.
Otherwise, the Iron Oxide-Sulfate complex, "Fe2O3 /SO4-2", shouldn't be too hard to whip up. Additionally, the Claims go on to explain, that, while this process can "yield a reaction product having a ratio of liquid to gaseous hydrocarbons in said product in excess of 8:1 by weight and a liquid content in excess of 50% of the weight of coal", it can also be made to yield a liquid product "in excess of 70% of the weight of coal". How much "in excess" they don't say, but, it seems to do with how much/how many "gaseous hydrocarbons are desired as product, with the ratios of production being somewhat controllable.)
Background and Field: The invention is a short residence coal liquefaction process in which more than fifty percent of the carbon in coal is converted to liquids, while limiting production of hydrocarbon (HC) gases, resulting in high ratios of liquids/HC gases.
Structurally, bituminous coal typically consists of monocyclic and condensed aromatic and hydroaromatic rings (clusters), varying in size from a single ring to perhaps four or five rings, which are linked to each other by connecting bridges which are typically short aliphatic chains or etheric linkages. Generally, coal liquefaction processes occur in the temperature range of 400C-500C by rupturing the connecting bridges to form free radicals. The free radicals are then capped by a small entity such as hydrogen. If the free radicals are not capped, they will combine in condensation or polymerization reactions to produce large structures which will be solid at room temperature.
Prior art coal liquefaction processes can be grouped into four different types of processes: pyrolysis (including hydropyrolysis), solvent extraction, catalytic hydrogenation with a solvent, and Fischer-Tropsch which is an indirect process.
In pyrolysis processes, coal is heated to 400C to 500C in the absence of any reacting atmosphere or in the case of hydropyrolysis, a hydrogen atmosphere, but without an externally-applied catalyst. The connecting bridges between the condensed ring units are thermally ruptured and the free radicals which are formed are stabilized by capping with hydrogen which is abstracted from some of the structural units in the coal. The total yield of liquids and gases by pyrolysis is typically in the range of 40% by weight of the coal. The remaining 60% by weight of the coal is a solid residue known as char.
Solvent extraction processes typically involve dissolving coal in a hydrogen donor solvent and heating to 400C to 450C. One of the more advanced solvent extraction processes is the Exxon Donor Solvent Process of Exxon Oil Company. In this process a hydrogen donor solvent is added to coal feedstock to form a slurry which is then heated to a temperature of approximately 450C. for approximately 15-20 minutes. While heating, hydrogen gas is added to the slurry.
(The above-cited "United States Patent 4,345,989 - Catalytic Hydrogen-donor Liquefaction Process" is an advanced example of the "Exxon Donor Solvent Process". An earlier example can be accessed via:
West Virginia Coal Association | Esso/Exxon 1973 Integrated Coal Liquefaction Process | Research & Development; concerning: "United States Patent 3,726,784 - Integrated Coal Liquefaction and Hydrotreating Process; 1973; Assignee: Esso Research and Engineering Company; Abstract: A hydrotreated liquid product from coal is obtained by a process ... for producing hydrotreated liquid product from coal, which comprises: (subjecting) a slurry of coal particles in a hydrogen-donor solvent to coal liquefaction in the presence of hydrogen for a sufficient period of time and at a sufficient temperature to form a liquid product and a vaporous product";
and, there are even earlier, much earlier related Esso processes about which we thought we had reported, but which we are unable to access at this time. We will make effort to recap Esso's development of their "Donor Solvent" technologies.)
In catalytic hydrogenation with a solvent, coal is dissolved in a hydrogen donor solvent, e.g. tetralin, to form a slurry; a hydrogenation catalyst is then introduced into the slurry and the slurry is heated to above 400C. Hydrogen addition to the coal is approximately 4% to 5% by weight and the product is a liquid and gas (C1 and C4 hydrocarbons) at room temperature. One of the most successful examples of a catalytic hydrogenation with a solvent process is the H-Coal process developed by Hydrocarbon Research, Inc.
(See, for just one example, our report of:
New Jersey (!!!) Liquefies Coal | Research & Development; concerning the USDOE report: "'New technology concept for two-stage liquefaction of coal: conceptual commercial plant design and economics'; Hydrocarbon Research, Inc., NJ; Report: DOE/PC/60017-T2; Contract: AC22-83PC60017; Abstract: Hydrocarbon Research, Inc. (HRI) is conducting a program for the United States Department of Energy (DOE) for evaluation of a ''New Technology'' concept for Catalytic Two-Stage Liquefaction of coal.")
The Fischer-Tropsch coal liquefaction technology is the only liquefaction technology that is being utilized on a commercial scale. In the Fischer-Tropsch process, coal is gasified with oxygen and steam at a temperature which is usually above 950C to produce carbon monoxide and hydrogen. These gases are then reacted at a temperature of approximately 430C, in the presence of an appropriate catalyst, to form gaseous and liquid hydrocarbons.
(South Africa Synthetic Oil Limited, SASOL, is currently utilizing "Fischer-Tropsch coal liquefaction technology ... on a commercial scale". See, for one example of their take on the technology:
South Africa seeks US Coal-to-Jet Fuel Patent | Research & Development; concerning: "US Patent Application 20100264061A1 - Synthetic Aviation Fuel; 2010; Assignee: Sasol Technology Ltd., Johannesburg; Abstract: The invention relates to a Fischer-Tropsch derived aviation fuel, which fuel is used either as a fuel on its own or as a component in an aviation fuel blend ... . This invention relates to an improved Fischer-Tropsch derived aviation fuel. Distillate fuel derived from the Fischer-Tropsch (FT) process is highly paraffinic and has excellent burning properties and very low sulfur. This makes Fischer-Tropsch products ideally suited for fuel use where environmental concerns are important. Clean distillates with low emission characteristics that contain low sulfur, nitrogen or aromatics such as distillates from the Fischer-Tropsch process will in the future be in great demand as aviation fuel or in blending aviation fuel. The FT process is used industrially to convert synthesis gas, which may be derived from coal ... into hydrocarbons ranging from methane to species with molecular masses above 1400.")
In an alternative technology to produce hydrocarbons, coal is gasified to CO and H2, which are then converted, principally to methanol by well-known technology. The methanol is then converted to gasoline using the Mobil ZSM-5 catalyst.
(See, for example, our reports of:
Exxon Coal to Methanol | Research & Development | News; concerning: "US Patent 4,348,487 - Production of Methanol via Catalytic Coal Gasification; 1982; Assignee: Exxon Research and Engineering Company; Abstract: Methanol is produced by gasifying a carbonaceous feed material with steam"; and:
West Virginia Coal Association | ExxonMobil Coal to Methanol to Gasoline | Research & Development; concerning, in part: "United States Patent 4,035,430 - Conversion of Methanol to Gasoline; 1977; Assignee: Mobil Oil Corporation; Abstract: The conversion of methanol to gasoline boiling products in a plurality of sequentially arranged catalyst beds. This invention relates to the method and system for converting methanol to gasoline boiling components".)
The prior art direct coal liquefaction technologies produce large amounts of hydrocarbon (HC) gases, ratios of liquids to HC gases usually being of the order 3/1 to 4/1, with none reported greater than about 7/1. Residence times of the materials (reactants plus products) in the temperature zone above 350C are characteristically between 15 minutes and one hour. Such long exposure of the primary liquid molecules to temperatures above 350C results in extensive thermal cracking, yielding hydrocarbon gases. Since more than half of the gases thus formed is methane, this cracking results in large consumption of hydrogen.
Summary: The invention provides a coal liquefaction process in which more than fifty percent of the carbon in coal is converted to HC liquids The production of HC gases in the instant coal liquefaction process is minimal, thereby producing a high ratio of liquids to HC gases, generally in a ratio greater than 8/1 by weight The invention further conserves hydrogen, an expensive reactant, in the production of liquids from coal. A particular feature of this inventive coal liquefaction process is that reactor residence time of the coal is in the order of seconds, preferably less than ten seconds."
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Note, in the immediately foregoing, that this is a very fast, and thus high production, process; and, in many respects, is closely similar to that seen in our report of:
California Rocket Scientists Liquefy Coal | Research & Development; concerning: "United States Patent 4,243,509 - Coal Hydrogenation; 1981; Assignee: Rockwell International Corporation, CA; Abstract: Disclosure is made of a method and apparatus for reacting carbonaceous material such as pulverized coal with heated hydrogen to form hydrocarbon gases and liquids suitable for conversion to fuels".
One focus of our subject seems to be the conservation of "hydrogen, an expensive reactant"; and, thus, the process is structured so that only something "over fifty percent of the ... coal is converted" into hydrocarbon liquids. We don't know exactly how much "over fifty percent", although, in an extended discussion not reflected in our excerpts, the University of Utah scientists note that a Carbon conversion efficiency of over seventy percent can be realized.
We submit that to be a somewhat specious argument, since, as seen for one example in our report of:
More NASA Hydrogen from Water and Sunlight | Research & Development; concerning: "United States Patent 4,051,005 - Photolytic Production of Hydrogen; 1977; Assignee: United Technologies Corporation;
Government Interests: The invention described herein was made in the course of a contract with the National Aeronautics and Space Administration. Abstract: Hydrogen and oxygen are produced from water in a process involving the photo-dissociation of molecular bromine with radiant energy at wavelengths within the visible light region";
it should have been known, by 1998, when our subject, "United States Patent 5,783,065 - Method for Coal Liquefaction", was issued, that some very efficient technologies for generating Hydrogen, technologies powered by freely available environmental energy, i.e., sunlight, "radiant energy at wavelengths within the visible light region", were becoming available.
However, given that the process of our subject is a very fast reaction, "less than ten seconds", the speed might justify the trade-off of lower Carbon conversion; that, especially since, as seen, for one example, in:
Mobil Oil Converts CoalTL Residues to Hydrocarbon Syngas | Research & Development; concerning: "United States Patent 4,248,605 - Gasification of Coal Liquefaction Residues; 1981; Inventor: Michael Lancet, Pittsburgh; Assignee: Conoco, Inc.; Abstract: A method for gasifying the bottoms fraction from a coal liquefaction process ... to produce a hydrogen-rich fuel gas";
the technology exists to further treat the still-carbonaceous residues from a Coal conversion process, and convert them into a hydrocarbon synthesis gas blend of Carbon Monoxide and Hydrogen suitable for catalytic condensation, as via the Fischer-Tropsch synthesis, into more hydrocarbons.
Or, the technology also exists, as seen, for one example, in:
Exxon Converts Coal Conversion Residues to Cement | Research & Development; concerning: "United States Patent 4,260,421 - Cement Production from Coal Conversion Residues; 1981; Assignee: Exxon Research and Engineering Company: Abstract: Cement is produced by feeding residue solids containing carbonaceous material and ash constituents obtained from converting a carbonaceous feed material into liquids and/or gases into a cement-making zone and burning the carbon in the residue solids to supply at least a portion of the energy required to convert the solids into cement";
to use the still-carbonaceous residues from a primary Coal conversion process, such as the high-speed and Hydrogen-conserving system disclosed herein by subject, "United States Patent 5,783,065 - Method for Coal Liquefaction", in other constructive, profitable, and other resource-conserving, ways.