In many of our reports documenting and explaining how Coal can, through an initial gasification, be indirectly converted into liquid hydrocarbon substitutes for natural petroleum-based fuels, it can be seen that technologies wherein Coal is first "slurried" in one liquid or another, prior to gasification and conversion into the Carbon Monoxide and Hydrogen components of hydrocarbon synthesis gas, are often specified.
A representative phrase describing that procedure might be: "comminuted coal is first slurried in a mixture of", wherein "comminuted" means ground into fine particles, with the sizes of the particles often specified; and, wherein "slurried" simply means that the "comminuted coal" is mixed thoroughly into the liquid to form a thick suspension which can be pumped, and forced through nozzles into a combustion zone.
The technology differs from other Coal gasification processes, such those described as "fluidized bed techniques", wherein solid Coal, usually in coarser particles, even lumps, is gasified only, and sometimes kept in a lower-density suspension with, flowing gas streams comprised, variously, of Oxygen, Air, Steam and Carbon Dioxide.
As we've documented now in many reports, the formerly well-known Texaco, since absorbed into the Chevron conglomerate, embarked, starting soon after World War II, perhaps motivated by the Axis successes in converting Coal into liquid hydrocarbon fuels, on an intensive and extensive campaign of developing Carbon conversion technologies, with most of them centered on the gasification and indirect conversion of Coal, and other Carbon resources, into hydrocarbons.
Two early, but far from the earliest, examples of their indirect Coal gasification and conversion technology can be seen in:
Texaco 1950 Coal + Steam = Hydrocarbon Syngas | Research & Development; concerning: "United States Patent 2,516,974 - Gasifying Carbonaceous Material; 1950; Texaco Development Corporation; Abstract: The present invention relates to gasification of solid fuels and is more particularly concerned with the conversion of carbonaceous materials into a gaseous product of high heating value composed primarily of carbon monoxide and hydrogen ... . In accordance with the present invention a stream of combustible gases, predominantly hydrogen and carbon monoxide, is produced by the reaction of water vapor with carbon"; and:
Texaco 1954 Coal + Coal Oil + H2O = Syngas | Research & Development; concerning: "United States Patent 2,669,509 - Gasifying Carbonaceous Solids; 1954; Assignee: Texaco Development Corporation;
Abstract: This invention relates to a process for the gasification of solid carbonaceous materials (and) is particularly applicable to the treatment of coal ... . (This) this invention is particularly suited to the production of water gas, fuel gas or feed gas for the synthesis of hydrocarbons via the Fischer-Tropsch synthesis."
As we've also once or twice documented, and as suggested by the excerpted phrase, above, from "United States Patent 2,516,974", i.e., "the reaction of water vapor with carbon", Texaco also discovered that various other Carbon resources, many of them renewable wastes, could be treated in the same way, most often in combination with Coal, thus providing a route to a certain amount of sustainability, Coal conservation and indirect Carbon Dioxide recycling.
Since we intend in coming reports to further document the Coal and renewable Carbon combination potentials in Texaco's various processes for the indirect synthesis of assorted hydrocarbons, we wanted, herein, to record how a thorough technical knowledge base was established by Texaco, for first making the Carbon-containing slurry for gasification, which gasification was targeted both on the production of "substitute" natural gas, and of, as in "United States Patent 2,669,509", above, a "feed gas for the synthesis of hydrocarbons".
Although the United States Patents we submit in this report seem to center on the use of "lignite" and other "sub-bituminous" Coal, there is no reason they could not be applied to higher-quality bituminous Coal, as we mine in West Virginia, Ohio and, aside from a little anthracite, Pennsylvania.
Our perception, after some years sporadically reviewing the various Texaco Carbon conversion technologies, is that Texaco came to operate on the basis of a philosophy, that we have as yet been unable to find a published record of, i.e., that high-grade bituminous Coal was too valuable in it's conventional uses to be consumed in the synthesis of substitute natural gas or synthetic gasoline and diesel fuel.
Comment, and two additional links with comments, follows excerpts from the initial link in this dispatch to:
"United States Patent 4,104,035 - Preparation of Solid Fuel-Water Slurries
August, 1978
Inventors: Edward Cole, et. al., NY
Assignee: Texaco, Inc., NYC, NY
Abstract: Preparation of a solid fuel-water slurry suitable for use as feed to a partial oxidation zone for the production of synthesis gas by forming a mixture of finely-divided solid fuel and water, heating the mixture to a temperature above 300F under pressure sufficient to maintain water in the liquid phase, cooling the mixture and adding a surface active agent and sufficient water to form a mixture having a water content between 40 and 50 weight %.
Claims: A process for the preparation of a pumpable solid fuel-water slurry having a solids content measured on a dry basis of between about 50 and 60% by weight said solid fuel having a particle size such that at least 70% passes through a 200 mesh sieve which comprises subjecting finely-divided solid fuel selected from the group consisting of sub-bituminous coal and lignite to a hydrothermal treatment by forming a mixture of finely-divided solid fuel and water, heating the mixture to a temperature between about 300 and 700F under a pressure sufficient to maintain water in the liquid phase for a period of time between 1 minute and 2 hours under non-oxidizing conditions, separating the solid fuel from the water used to form said mixture and adding to said hydrothermally treated fuel having a particle size such that at least 70% passes through a 200 mesh sieve water in an amount to form a slurry containing about 50 to 60 wt. % solid fuel and also adding as a surface active agent a salt of an organic sulfonic acid in an amount to confer pumpability to said slurry.
(The "salt of an organic sulfonic acid" wouldn't be too expensive. As can be learned via:
Sulfonic acid - Wikipedia, the free encyclopedia; sulfonic acid and it's salts are inexpensive commodity chemicals commonly used as surfactants and detergents, and are utilized as additives in concrete.
Further, as will be seen as we go along, there are other options.)
The process ... in which the solid fuel is lignite (or) sub-bituminous coal.
Description: This invention relates to the production of solid fuel-water slurries. More particularly, it is concerned with the production of slurries of solid fuel in water, suitable for feed to a generator for gasification of the solid fuel by partial oxidation.
The gasification of solid fuels such as coal is well known.
In one method the solid fuel is ground to a fine powder and fed to the gas generator as a suspension in a vaporous medium e.g., steam or in a gaseous medium such as a free oxygen-containing gas.
It is therefore an object of this invention to produce solid fuel-water slurries having a high solids content.
Another object is to form coal water-slurries suitable for use as feed to a gas generator.
According to our invention there is provided a process for the gasification of a solid fuel which comprises forming a mixture of a finely-divided solid fuel and water, heating the resulting mixture under pressure sufficient to maintain the water in liquid phase, cooling the mixture, forming the so-treated solid fuel into a water-solid fuel slurry having a solids content between about 50 and 60 wt. % on a dry basis, adding a surface active agent to said slurry in an amount to form a pumpable slurry, and introducing the slurry into a gasification zone.
The process of our invention may be applied to any solid fuel such as coal ...but it is particularly adapted to sub-bituminous coal and lignite which contain relatively large amounts of water as mined."
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Thus, it seems the only reason, for specifying lignite and sub-bituminous Coal is because they already contain a certain amount of the needed water.
We don't suppose, though, that adding a little extra water would be much of a problem along the Ohio or Allegheny or Kanawha Rivers.
In any case, Texaco continued to improve their technology for preparing a slurry of particulate Coal suitable for gasification, and conversion into hydrocarbon synthesis gas, as seen in:
"United States Patent: 4623359 - Aqueous Slurries of Solid Carbonaceous Fuel
Date: November, 1986
Inventors: Farrokh Yaghmaie, et. al., NY
Assignee: Texaco, Inc., NY
Abstract: Aqueous slurries of solid carbonaceous fuel that include a novel highly converted sulfonated surfactant derived from a suspension of low rank coal and coal derived creosote oil for reducing the viscosity and increasing the solids content of the aqueous slurry.
(Note that many technologies for creating a Coal-Water slurry for gasification do specify the inclusion of a liquid hydrocarbon, along with the Coal and the Water. As seen herein, a crude Coke oven tar, "creosote oil", is an acceptable liquid carrier. No natural petroleum needs to be harmed in the making of Coal-derived hydrocarbon fuels.)
Claims: A solid carbonaceous fuel-water slurry which comprises: about 50 to 70 weight % of comminuted solid carbonaceous fuel (and) about 0.5 to 8.0 weight % of a water-soluble surfactant derived from a suspension of low rank coal and coal derived creosote oil.
(And) wherein said solid carbonaceous fuel is selected from the group consisting of coal, coke from coal, char from coal, ... particulate carbon soot ...and mixtures thereof.
The solid carbonaceous fuel-water slurry ... wherein the low rank coal in (ii) is oxidized by the steps of gradually stirring into said aqueous slurry from about 10-20 ml of 20-40 volume % hydrogen peroxide for each 100 grams of low rank coal, and then destroying any excess peroxide.
(There are some seemingly-sophisticated treatments and pre-treatments for the Coal slurry specified herein by Texaco. None of them, though, seem to require very expensive chemicals. The "hydrogen peroxide" specified above is a relatively inexpensive commodity that seems to "pre-oxidize" the Coal to a certain extent, thereby making the Coal easier to gasify.)
Background and Field: This invention relates to aqueous slurries of solid carbonaceous fuel. More particularly, the present invention relates to a novel highly converted sulfonated water-soluble surfactant derived from a suspension of low rank coal and coal derived creosote oil, its method of production, and its use in aqueous slurries of solid carbonaceous fuel to reduce viscosity and increase solids content, thereby improving pumpability.
Performance of a Texaco entrained flow partial oxidation gas generator may be affected by the nature of the aqueous slurry feedstock. For example, particle size of the solid carbonaceous fuel and solids content of the aqueous slurry influence the viscosity and pumpability of the slurry. A finer grind size may produce a higher carbon conversion for the same oxidant feedrate. However, the finer the grind size, the higher the grinding cost due to greater expenditures for equipment and electric power. Also, the finer the grind size, the greater the viscosity for slurries having the same solids content. Pumping costs go up as the viscosity of the slurry increases. Further, the efficiency of the partial oxidation process decreases when the solids content of the slurry drops off and excessive water is present.
By means of the subject invention, aqueous slurries of solid carbonaceous fuel may be prepared having a higher solids content and reduced viscosity, at a great economic benefit."
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As Texaco explains in the full, and quite detailed, Disclosure, much of the "great economic benefit" arises from a decrease in grinding costs for the Coal. Because of their unique blend of surfactants, the Coal doesn't have to be ground nearly as fine as might otherwise be the case to form a stable suspension of Coal in the slurry, a slurry that can still be pumped into a gasifier.
Further, they go on to describe how the needed "sulfonated surfactant" can be made by treating Creosote oil with Sulfuric Acid.
We haven't reproduced the details, since they are technically somewhat dense. However, keep in mind that we can make the needed Sulfuric Acid, as seen in:
USDOE Makes Hydrogen by Using Sulfur Dioxide | Research & Development; concerning: "United States Patent 4,244,794 - Hydrogen Production by the Decomposition of Water; 1981; Assignee: The USA; This invention relates generally to the production of hydrogen gas from water and in particular relates to a sulfuric acid process for producing hydrogen. It is a result of a contract with the Department of Energy. Claims: A process for producing hydrogen comprising: passing an electric current from a cathode to an anode through water containing sulfur dioxide so as to produce hydrogen gas at the cathode and so as to oxidize the sulfur dioxide to form sulfuric acid at the anode, thus producing an aqueous solution of sulfuric acid";
along with Hydrogen, for hydrogenating Coal liquids and Coal syngas, from the aqueous effluent of a smoke stack scrubber that removes Sulfur Dioxide from industrial exhaust gases - perhaps those from a power generating station burning high-Sulfur Coal.
And, Texaco continued to refine those Coal gasification slurry preparation technologies, improving them to the point where it became unnecessary to take the extra step of including, as in United States Patents 4,623,359 and 4,104,035, above, an additional "surfactant derived from a suspension of low rank coal and coal derived creosote oil".
Further, Texaco specifies that another, very, very intriguing "carbonaceous fuel" can be utilized, in addition to raw Coal, to make the gasification slurry.
As seen in:
"United States Patent: 4749381 - Stable Slurries of Solid Carbonaceous Fuel and Water
Date: June, 1988
Inventors: Farrokh Yaghmaie, et. al., NY
Assignee: Texaco, Inc., NY
Abstract: A pumpable slurry of solid carbonaceous fuel and water with reduced viscosity and increased resistance to sedimentation comprising about 50 to 75 weight percent of comminuted solid carbonaceous fuel having less than 10.0 weight percent of combined oxygen, about 0.1 to 10.0 weight percent of a surfactant comprising an anionic or nonionic adduct of a mono or dialkyl phenol and polyoxyethylene or polyoxypropylene, and the remainder of the slurry is water.
A pumpable slurry of solid carbonaceous fuel and water with reduced viscosity and sedimentation rate for use as feed to a partial oxidation gas generator for the production of raw synthesis gas ... ,
(Said) slurry comprising about 50 to 75 weight percent of high rank comminuted solid carbonaceous fuel having 5.0 weight percent or below of organically combined oxygen wherein said solid carbonaceous fuel is selected from the group consisting of anthracite coal (and/or) coal liquefaction solid residue ... ,
(Note: As seen in, for just one example, our earlier report of:
Consol Hydrogasifies CoalTL Residues | Research & Development; concerning: "United States Patent 4,248,605 - Gasification of Coal Liquefaction Residues; 1981; Inventor: Michael Lancet, Pittsburgh; Assignee: Conoco; Abstract: A method for gasifying the bottoms fraction from a coal liquefaction process by mixing the bottoms fraction with at least one finely-divided calcium compound selected from the group consisting of calcium oxide, calcium carbonate and calcium hydroxide ... in an amount sufficient to produce agglomerate particles upon mixing with the bottoms fraction and thereafter gasifying the resulting agglomerate particles by reacting the agglomerate particles with steam in a fluidized bed";
as with our subject herein, Texaco's process of "USP 4,749,381", there was so much knowledge concerning Coal liquefaction technology extant in the US petroleum and mining industries, fully three decades ago, that multiple petroleum companies devoted significant effort not only to develop more advanced Coal liquefaction processes, but, to develop technologies for efficiently extracting and utilizing any and all Carbon which might not be completely used up and converted into liquid hydrocarbons by those processes.)
The subject invention deals with stable pumpable slurries of medium to high rank solid carbonaceous fuel and water. While these slurry compositions have a high solids content, e.g. 50 to 70 weight percent, they are pumpable and have a low viscosity and reduced sedimentation rate in comparison with other solid fuel and water slurries with the same solid content. The suspension of coal particles in water is desired for transportation and processing. Fast sedimentation of coal particles can cause operational difficulties.
The excellent pumpability of the subject slurries permits them to be transported long distances by pipeline without the solids settling out. The slurries make excellent fuels for boilers and improved feedstocks for the partial oxidation process. For example, in coassigned U.S. Pat. No. 3,544,291, which is incorporated herein by reference, aqueous slurries of solid carbonaceous fuel are reacted with a free oxygen containing gas by partial oxidation to produce synthesis gas, reducing gas, and fuel gas."
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We'll close our excerpts there, since they make reference to the related "U.S. Pat. No. 3,544,291", so that we can remind you of our earlier report:
Texaco 1970 Coal + H2O = Hydrocarbon Syngas | Research & Development; concerning: "United States Patent 3,544,291 - Coal Gasification Process; 1970; Assignee: Texaco, Incorporated, NY; Abstract: A process for gasification of solid fuel by partial oxidation to produce carbon monoxide and hydrogen ... in which pulverized solid fuel, such as coal ... is supplied to the reactor as a slurry with water. This invention relates to a process for the production of carbon monoxide and hydrogen, i.e., synthesis gas, from solid carbonaceous fuels".
And, we urge you to keep in mind that the whole purpose of making, as herein so efficiently, a blend of "carbon monoxide and hydrogen, i.e., synthesis gas, from" our favorite "solid carbonaceous fuels", i.e., various Coals, is so that, as in just one variation of such technology, the:
Fischer–Tropsch process - Wikipedia, the free encyclopedia; "The Fischer-Tropsch process (or Fischer–Tropsch Synthesis) is a set of chemical reactions that convert a mixture of carbon monoxide and hydrogen into liquid hydrocarbons";
we can start converting those blends of Coal-derived Carbon Monoxide and Hydrogen into anything we now fight foreign OPEC wars and mortgage the financial future of our nation for the supply of.