United States Patent: 4331530

Herein, in a process that requires only moderate, in chemical industry processing terms, temperatures and pressures, California's Occidental Petroleum, aka "Oxy", explains how very nearly 90% of the Carbon in a feed of any type or quality of raw Coal can be converted into Gasoline, and Gasoline blending stock.

Further, any residual, unconverted Carbon is specified by Oxy to then be utilized to help supply the Hydrogen for the hydrogenation and liquefaction of the Coal.

Conversely, the option also exists to instead, or as well, convert the Coal into, essentially, synthetic natural gas, with the co-generation of other useable by-products.

None of those potentials should be surprising to you, presuming you to have followed our posts thus far or to have accessed and studied the Research and Development archives made web-accessible on their site by the West Virginia Coal Association.

Comment, with additional reference links, follows and is inserted within excerpts from the above link to:

"United States Patent 4,331,530 - Process for the Conversion of Coal

Date: May, 1982

Inventor: Shaik Qader, California

Assignee: Occidental Research Corporation, California

(For those unfamiliar with "Oxy", see:

Occidental Petroleum - Wikipedia, the free encyclopedia; which informs, that: "'Oxy' is the largest oil producer in Texas and the largest natural gas producer and third-largest producer of oil in California, with additional operations in Kansas, North Dakota, Utah, Oklahoma, Colorado and New Mexico"; and:

Oxy | Home, wherein we can learn, that: "Occidental Petroleum Corporation (NYSE:OXY) is an international oil and gas exploration and production company, the fourth-largest in the U.S., based on market capitalization, and our OxyChem subsidiary is a major North American chemical manufacturer".)

Abstract: A process for the hydrogenation of coal and subsequent treatment of hydrogenated coal to produce useful fuels and chemicals which comprises comminuting coal ore to a particle size range of from about 150 mesh to about 250 mesh; hydrogenating the particulate coal in the presence of a hydrogenation catalyst and a source of hydrogen at a temperature of from about 100 to about 300 C. and a pressure of from about 500 to about 1,000 psi for a time sufficient to react hydrogen with the coal to form predominantly hydroaromatic coal; and recovering the hydrogenated coal. The hydrogenated coal is subsequently hydrocracked or pyrolyzed. The hydrogenated coal is hydrocracked at from about 500 to about 700 C. a pressure of from about 500 to about 2,000 psi for a time sufficient to crack the coal to produce benzene, toluene, xylene and gasoline. The hydrogenated coal is pyrolyzed at from about 400 to about 700 C., at a pressure of about atmospheric pressure and for a time sufficient to convert the coal to C1 - C4 gaseous hydrocarbons, naphtha and tar.

(Note: "C1 - C4 gaseous hydrocarbons" = methane (C1), ethane (C2), propane (C3) and butane (C4), a blend which could be considered as a substitute natural gas. Keep that in mind, since it figures in later on.

Further note, somewhat unfortunately, the specification that the Coal particles be reduced in size to "150 mesh to about 250 mesh". By that, they almost certainly mean as measured by what's known as the "Tyler" scale. If so, and if we read the web-accessible conversion charts correctly, a big if, then the Coal would have to be ground to what is technically referred to as "powder", with a particle size of one-tenth of a millimeter, or less. If we do have that right, that's pretty-darned fine, and a good deal of energy would have to be expended to grind the Coal.

However, again if we understand the literature correctly, that is well within the range of Coal particle sizes utilized by more modern, more efficient Coal-fired power plant boilers; and, a substantial number of suppliers can supply the needed Coal "mills", or "pulverizers".

We're certain any number of Coal Country power plant engineers could explain it all far better than we are able to. The essence is, though, that grinding Coal to "150 mesh to about 250 mesh" is a practice already commercialized and in use. It is quite "do-able" on a genuinely efficient industrial scale.)

Claims: A process for the hydrogenation of coal which comprises: 

(a) comminuting coal ore to a particle size range of from about 150 mesh to about 250 mesh; 

(b) hydrogenating the particulate coal in a hydrogenation zone in the presence of a hydrogenation catalyst in the vapor phase and selected from the group consisting of halides of zinc and tin, carbonyls of cobalt, iron, transition metals selected from Groups VI, VII and VIII of the Periodic Table, and mixtures thereof, and hydrogen at a temperature of from about 100 to about 300C and a pressure of from about 500 to about 1,000 psi for a time sufficient to react hydrogen with the coal to form predominantly hydroaromatic coal; and 

(c) recovering the hydrogenated, hydroaromatic coal from the hydrogenation zone.

(First, concerning the use of "halides of zinc" as a Coal hydrogenation catalyst, see, for just two examples, our earlier reports of:

Shell Oil Cracks Coal with Zinc Halide | Research & Development; concerning: "United States Patent 3,764,515 - Process for Hydrocracking Heavy Hydrocarbons; 1973; Assignee: Shell Oil Company, NY; 
Abstract: There is disclosed a process for hydrocracking coal ... employing a ... metal halide catalyst selected from zinc chloride, bromide or iodide"; and:

Consol 1967 Coal Tar to Gasoline | Research & Development; which relates details of: "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 (in a) process for converting polynuclear aromatic hydrocarbonaceous feedstock to gasoline".

There other examples of similar technologies employing Zinc Halide among our earlier reports. Its use in the hydrogenation of Coal is well-known, long-established and won't break the bank.)

The process ... wherein the catalyst is recovered from the hydrogenated coal and is recycled to the hydrogenation zone.

(See, for instance, our earlier report of:

Exxon Recovers and Recycles Coal Conversion Catalyst | Research & Development; concerning: "United States Patent 4,157,246 - Hydrothermal Alkali Metal Catalyst Recovery Process; 1979; Assignee: Exxon Research and Engineering Company; Abstract: In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles primarily in the form of water soluble alkali metal formates by treating the particles with a calcium or magnesium-containing compound in the presence of water ... and in the presence of added carbon monoxide ... and recycled to the gasification process ... thereby decreasing the overall cost of the gasification process";

with other reports of similar catalyst-conserving, economizing Coal conversion technology to follow.) 

The process ... wherein the hydrogen for the hydrogenation step is generated by the gasification of the char produced during the hydrocracking.

(Concerning the above "gasification of the char" co-produced during an initial stage of Coal hydrogenation, see, for one example:

Mobil Oil Converts CoalTL Residues to Hydrocarbon Syngas | Research & Development; concerning: "United States Patent 4,583,993 - Carbon Monoxide and Hydrogen from Carbonaceous Material; 1986; Assignee: Mobil Oil Corporation; Abstract: Hydrogen and carbon monoxide are produced from  (the) char product of coal solvation (and) char product of coal volatilization".

The "Hydrogen" generated by such a process, from "char produced during the hydrocracking" of Coal, as specified herein by Oxy, can be cycled back to, and utilized in, the initial Coal "hydrogenation step".

The rather immensely-valuable by-product "carbon monoxide" could, we submit, then be separated and utilized in another process, such as those seen, for several examples, in our reports of:

Standard Oil Carbon Monoxide + Water = Gasoline | Research & Development; concerning: "United States Patent 4,559,363 - Process for Reacting Carbon Monoxide and Water; 1985; Abstract: A process for reacting carbon monoxide and water in the presence of a cadmium-containing catalyst ... for the direct production of gasoline"; and:

USDOE Carbon Monoxide + H2O = Alcohol | Research & Development; concerning: "United States Patent 4,656,152 - Catalyst for Producing Lower Alcohols; 1987; Assignee: The United States of America, as represented by the Secretary of the USDOE; Abstract: A process and system for the production of the lower alcohols such as methanol, ethanol and propanol involves the reaction of carbon monoxide and water"; and:

Exxon Hydrogenates Coal with Water and Carbon Monoxide | Research & Development; concerning: "United States Patent 5,026,475 - Coal Hydroconversion Process; 1991; Assignee: Exxon Research and Engineering Company; Abstract: An improved process for the hydroconversion of coal comprising pretreating coal in an aqueous carbon monoxide-containing environment, followed by extracting a soluble hydrocarbon material from the coal, and subsequently hydroconverting the extracted material".)

(And) recovering the hydrogenated, hydroaromatic coal from the hydrogenation catalyst; and pyrolyzing the hydrogenated coal in a pyrolysis zone at a temperature of from about 400 to about 700C at about atmospheric pressure for a time sufficient to produce C1 - C4 gaseous hydrocarbons, naphtha and char. 

The process ... wherein the hydrogen for the hydrogenation is generated by the gasification of the char produced during the pyrolysis.

(Again, the opportunity to gasify more carbonaceous residues and thereby generate more Carbon Monoxide and more Hydrogen for appropriate utilization. Note, as well, that, as can be learned via:

Naphtha - Wikipedia, the free encyclopedia;

the co-product "naphtha", as above, is also of great potential value. The word "naphtha" is actually a label applied to a somewhat variable blend of certain, specific flammable liquid hydrocarbons that all fall within a certain boiling range and are among the "lightest and most volatile fractions" of petroleum liquids; and, it has long been known that naphtha can as well be made by distilling Coal. Further, it's primary current use is in the production of high octane gasoline.).

Background and Description: Increasing energy needs have focused attention on solid fossil fuels due to their availability in the United States in a relatively abundant supply and their potential value when converted into more useful forms of energy and feedstock. Coal is known to be a potential valuable source of chemical compounds as well, and considerable effort has been expended in attempts to develop a process for the efficient production of such chemicals and such fuel products. 

It has been proposed to hydrogenate coal with hydrogen gas in the presence of a solvent and a catalyst at moderate to severe conditions of temperature and pressure. The product is determined by the reaction conditions, catalyst, and space velocity or residence time. It has been widely accepted that coal does not begin to decompose until it has reached the temperature of about 350 to about 400C. At the temperatures generally employed for such hydrogenation, hitherto generally above 400C., the coal substance breaks down, the molecular chains in the coal being cleaved to from lower molecular weight substances. These products often have a molecular size such that they are suitable for use as fuel oils or the like, and they can be subjected to hydrocracking for conversion into "synthetic gasoline." 

In the state-of-the-art hydrogenation processes, a recyclable "pasting oil" was necessary to initially dissolve or slurry the raw coal. The slurry of coal, usually containing a catalyst, was generally heated in the presence of hydrogen gas at about 450 to 550C and about 2,000 to 10,000 psig. Following hydrogenation finely-divided unreacted coal ash had to be filtered or otherwise removed from the heavy, viscous primary oil product. These processes, generally were not commercially acceptable because of the large capital investment, the high operating costs and the hydrogen requirements were too high in comparison with the value of the products obtained. 

More recently, dry hydrogenation processes have been developed wherein coal is heated with hydrogen gas. However, these processes are generally batch-type processes and because they are conducted at greatly elevated temperatures and pressures, result in the production of hydrocarbon gases and liquids useful mainly as fuel.

Summary: In accordance with the present invention, there is provided a process for the conversion of predominantly aromatic coals to predominantly hydroaromatic and highly reactive coals by low temperature and low pressure hydrogenation using a gaseous or solid catalyst. Non-metallurgical coals also get converted to metallurgical coals. The hydrogenation reaction occurs in the temperature range of about 100 to about 300C and at a pressure of from about 500 to about 1,000 psi in dry phase. Residence time can be from about 10 seconds to about 10 minutes. Coals of all ranks can be hydrogenated without any agglomeration problems since the reaction takes place well below the plastic range. Reaction can be carried out in fixed, entrained, moving and fluidized bed systems. The yield of hydrogenated coal is from about 101 to 103 percent of the raw coal on maf basis.

(Note: The "maf basis" means the weight of the raw Coal minus the weight of it's contained Moisture and mineral Ash, i.e., "Moisture (and) Ash Free".)

Hydrogen consumption varies from about 1 to about 3 percent and catalyst consumption negligible. The aromatic structures present in the coal are hydrogenated to hydroaromatic structures without cracking of the structures. The process produces reactive, solid hydroaromatic coal which can be easily converted to liquid fuels and chemicals by cracking and pyrolytic processes.

(It doesn't seem as if that much Hydrogen is actually needed in or consumed by the process. But, if we need more than we can get by steam-gasifying the Char, as described above, then supplementary processes, such as that seen 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 (and) wherein the source of radiation is sunlight";

can make all of the Hydrogen we might need in a process that actually consumes, in the case of the above NASA technology, since the "bromine" is recycled within the process, only Water and Sunlight.)

Further, there is provided a second step in the process for the conversion of coal wherein the hydroaromatic product of the select low temperature and low pressure hydrogenation can be hydrocracked at from about 500 to about 700 C. under a pressure of about 500 to about 2,000 psi. Residence time can range from about 1 to about 60 seconds and no catalyst is required. Conversion of the coal varies between about 60 to about 90 percent.

The hydrocracking products are benzene, toluene, xylene and gasoline.

(Note that "benzene, toluene" and "xylene" comprise what is commonly known in the trade as "BTX", also a Gasoline blending stock; or, which hydrocarbons can be separately utilized in other industries. Toluene, especially, though itself an unpleasant substance, has importance in the making of some types of polyurethane foams used in energy-conserving insulation applications.)

Alternatively, the hydroaromatic product of the select low temperature and low pressure hydrogenation is pyrolyzed at from about 400 to about 700 C at atmospheric pressure. Residence time varies from about 1 to about 60 seconds. Conversion of the coal ranges from about 60 to about 80 percent and liquid yield is about 50 to about 60 percent. The coal is mainly converted to C1 - C4 hydrocarbons, naphtha and tar.

(Concerning our inserted comments, above, regarding the by-product "C1 - C4 hydrocarbons", our read of the full disclosure is that they would consist mostly of Methane, and, we remind you, that, as seen for just one example in:

Exxon 2010 CO2 + Methane = Liquid Hydrocarbons | Research & Development; concerning: "United States Patent 7,772,447 - Production of Liquid Hydrocarbons from Methane; 2010; Assignee: ExxonMobil; Abstract: (A) process for converting methane to liquid hydrocarbons ... comprising: (a) contacting a feed containing methane and ...  H2O (and) CO2 with a (specified) catalyst under conditions effective to convert said methane to aromatic hydrocarbons, including benzene and naphthalene, and produce a first effluent stream comprising aromatic hydrocarbons and hydrogen";

we can use that Methane to convert any Carbon Dioxide, a relatively small amount of which, as we read it, is co-produced at one or two stages in the process of our subject, "United States Patent 4,331,530 - Process for the Conversion of Coal', such as during the "gasification of the char". And, we suggest that such combined usages could raise the initial, "87%" consumption of the Carbon in the Coal feed to much closer to a "100%" usage, with no, or negligible, greenhouse gas CO2 emissions from the total process.

We addressed the quite valuable "naphtha" in inserted comments, above. And, as far as the co-product "tar" goes, that, too, as in our above citation of Consol's "United States Patent 3,355,376 - Hydrocracking of Polynuclear Hydrocarbons", and, as seen in:

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; 2009; Abstract: The hydrogenation of naphthalene and coal-tar distillates has been carried out ... for the hydrogenated product, tetralin ... (which can be used to effect) the direct reaction between coal and hydrogen (and) the conversion of coal to refinable crude hydrocarbons, from which liquid fuels such as gasoline, diesel, kerosene, etc., can be produced";

can be employed in entertaining ways.)

According to the present invention there is provided a process for the conversion of coal to liquid fuels and useful chemicals by the hydrogenation of the coal and subsequent hydrocracking of the hydrogenated coal produced thereby."

-----------------------

This is a rather complete technology for the conversion of Coal into various hydrocarbons that, in and of itself, can lead to the use of, essentially, 90% of the available Carbon in the raw Coal in the making of various gasoline blending stock components and a relatively smaller amount of substitute natural gas.

Carbon loss seems mainly to be through the formation of Carbon Monoxide, and perhaps some Carbon Dioxide, in the secondary gasification of the hydrogenation residues; and, in the co-production of some amount of "tar".

But, since, with the appropriate "follow-on" technologies, examples of which we cited in our above exposition, those by-products, too, can be utilized in the production of various hydrocarbons, it seems legitimate to us to claim that very nearly, perhaps fully, 100% of the Carbon in Coal can be so utilized.

And, the basis for that complete industrial utilization of Coal, in the making of products we seem to so desperately need that we're willing to mortgage our nation for the supply of from largely unfriendly foreign powers, our subject herein, "United States Patent 4,331,530 - Process for the Conversion of Coal", was established very nearly three full decades ago in a state where they mine no Coal.

Why is it, that, in some states where we definitely do mine some Coal, we haven't been privileged to be publicly told about any of it?


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