Since we have been, and will more extensively be, making report of the rather vast body of knowledge and established commercial technology that exists for the productive recycling and reuse of Coal Combustion Products, "CCP's", or, as we prefer, Coal Utilization Byproducts, "CUB's", as, for one recent example, in:
Coal Ash Can Reduce Construction Costs | Research & Development; concerning: "United States Patent 5,624,491 - Compressive Strength of Concrete and Mortar Containing Fly Ash; 1997; Assignee: New Jersey Institute of Technology; Abstract: The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction ... , concrete and mortar containing about 15% to 25% fly ash as a replacement for cement, which are capable of meeting design specifications required for building and highway construction, are provided. Such materials can thus significantly reduce construction costs. Government Interests: The research leading to the present invention was conducted with Government support under Contract No. DE-FG22-90PC90299 awarded by the Department of Energy. The Government has certain rights in this invention";
we wanted to again affirm that "CUB's" arising from the use of Coal in applications other than in combustion for the generation of electrical power, since they are comprised of exactly the same inorganic mineral constituents, can also be reclaimed an utilized in similar fashions.
We have documented that fact at least once previously, as in our report of:
West Virginia Coal Association | 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".
We further note that, in addition to Exxon, now ExxonMobil, as in the above "US Patent 4,260,421", other petroleum producers, such as Shell Oil, acknowledge that Coal can be converted into hydrocarbon "liquids and/or gases"; as, for instance, seen in:
West Virginia Coal Association | Shell Hydrogenates Coal Syngas, Recycles CO2 | Research & Development; concerning: "United States Patent 5,431,703 - Method of Quenching Synthesis Gas; 1995;
Assignee: Shell Oil Company, Houston; Abstract: The invention is a process for quenching a first synthesis gas mixture containing synthesis gas, molten fly ash, water and carbon dioxide and producing additional synthesis gas (by) passing first synthesis gas mixture into a ... mixture of pulverized coal in a ... carbon dioxide carrier gas (and) endothermically reacting the pulverized coal with the water and the carbon dioxide to produce additional synthesis gas. The gases resulting from a partial combustion or gasification of coal have value as ... starting materials for synthesis of chemicals and fuels"; and:
Shell Oil Coal to Gasoline with By-Product Isobutane | Research & Development; concerning: "United States Patent 4,218,388 - Preparing Hydrocarbons from Gasification of Coal; 1980; Assignee: Shell Oil Company, Houston; Abstract: Synthesis gas is converted into gasoline by contacting the gas with a crystalline aluminosilicate zeolite catalyst, the process being characterized by conversion of by-product isobutane into gasoline by alkylation. A process for preparing liquid hydrocarbons from coal, comprising: converting coal into a mixture of carbon monoxide and hydrogen by gasification ...; converting the mixture of carbon monoxide and hydrogen into an aromatic hydrocarbon mixture in the presence of a catalyst which contains a crystalline aluminosilicate zeolite (as specified); separating from the aromatic hydrocarbon mixture an isobutane-containing gaseous fraction and an aromatic liquid fraction boiling in the gasoline range; converting the isobutane-containing gaseous fraction by alkylation into a product from which a fraction boiling in the gasoline range is separated; and mixing the two fractions boiling in the gasoline range".
And, we wanted herein to demonstrate that Shell Oil's Coal conversion technology has reached a level of sophistication similar, if not equivalent, to that of Exxon, as expressed in the above-cited "United States Patent 4,260,421 - Cement Production from Coal Conversion Residues".
Although they haven't taken their thinking as far as devising ways in which solid CUB's arising from Coal conversion processes can be productively utilized, they have at least developed efficient ways in which they can be removed from the product streams of those Coal conversion processes.
As seen in excerpts from the initial link in this dispatch, with an additional, related link and excerpts following:
"United States Patent 4,838,898 - Removal and Disposal of Fly Ash from a ... Synthesis Gas Stream
Date: June, 1989
Inventors: Thomas Mifflin and Thomas Dewitz, Texas
Assignee: Shell Oil Company, Houston
Abstract: A process for the partial combustion of finely-divided coal at high temperatures and pressures to make synthesis gas having entrained particles of fly ash which are separated from the gas at high pressure. The fly ash and a minor amount of entrained gas are handled in a batchwise manner to isolate a batch in a lock hopper, depressurize the batch, strip the synthesis gas from the fly ash and cool the fly ash prior to disposal.
Claims: In a process for the production of synthesis gas wherein coal is partially oxidized at an elevated temperature and pressure by feeding finely-divided coal and oxygen to a gasification zone of a reactor, the ratio of coal to oxygen being such as to maintain a reducing atmosphere, and producing raw synthesis gas having a temperature of from 2000F to 3000F, said gas carrying with it a minor amount of at least one contaminating substance which is normally solid in form at room temperature, and partially cooling said synthesis gas sufficient to solidify said contaminating substance carried thereby.
The method ... wherein the particles of solid contaminating substance are essentially fly ash.
Background: The invention relates to a process for the partial combustion of finely-divided solid fuel, such as pulverized coal, in which the latter is introduced together with oxygen-containing gas via a burner into a reactor or gasifier from which a stream of high-temperature raw synthesis gas is discharged together with a minor amount of contaminating material, most of which is in the form of particles of fly ash.
Partial combustion is the reaction of all of the fuel particles with a substoichiometrical amount of oxygen, either introduced in pure form or admixed with other gases ... whereby the fuel is partially oxidized to hydrogen and carbon monoxide. This partial combustion differs from complete combustion wherein the fuel would be completely oxidized to carbon dioxide and water.
The present invention is directed to a process for the partial combustion of finely-divided carbonaceous fuel containing at least 1% by weight ash in a reactor or gasifier to produce a product gas (mainly carbon monoxide and hydrogen) which carries along with it, as it leaves the reactor, sticky particles of fly ash or fly slag, or ash-forming constituents which may consist of alkali metal chlorides, silicon and/or aluminum oxides.
Any disposal or desired use of the fly ash may be made and such use is not part of this invention."
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And, that seems an appropriate place to close our excerpts, since Shell do suggest there might be such a thing as a "desired use of the fly ash" recovered from a synthesis gas made from Coal, which syngas presumably could be directed into that Shell-developed process of the above-cited "United States Patent 4,218,388 - Preparing Hydrocarbons from Gasification of Coal", for the further production of hydrocarbons "boiling in the gasoline range".
In passing, since they do acknowledge that "aluminum oxides" could be a component of the "fly ash" they recover from the "synthesis gas" made herein from Coal, we remind you that, as explained in:
USDOE Says Coal Ash Could End Aluminum Ore Imports | Research & Development; concerning the: "Economic Metal Recovery from Fly Ash; 1981; Oak Ridge National Laboratory, USDOE; Abstract: Although most coal combustion ash produced in the United States is discarded as a waste, results are presented to show that fly ash can be an economical source of Al2O3, Fe2/O3, and possibly several other metals, many of which are presently being imported"; and, in:
West Virginia Coal Association | Iowa Mines Metals from Coal Ash for the USDOE | Research & Development; concerning: "US Patent 4,397,822 - Process for the Recovery of Alumina from Fly Ash; 1983; Government Interests: The United States Government has rights in this invention pursuant to Contract No. W-7405-ENG-82 between the U.S. Department of Energy and Ames Laboratory. Abstract: An improvement in the lime-sinter process for recovering alumina from pulverized coal fly ash is disclosed";
the technologies, and economic justifications, exist to treat any Coal-derived fly ash as a source of Aluminum ore.
In any case, the above Shell Oil process for the recovery of fly ash from Coal-derived hydrocarbon synthesis gas streams is complemented by another, closely related technology developed by Shell, as seen in:
"United States Patent: 4976755 - Stripping and Depressurization of Solids and Gas Mixture
Date: December, 1990
Inventor: Thomas Dewitz, Texas
Assignee: Shell Oil Company, Houston
Abstract: An apparatus and method for stripping and depressurizing fine particulates mixed with gas discharged from a vessel operated at elevated temperature and pressure conditions to a low pressure vessel using a purge gas injected into a conduit designed for significant frictional pressure loss per unit length of conduit while maintaining a substantially constant velocity of the mixture conveyed.
Claims: An apparatus for stripping and depressurizing fine particulates mixed with gas discharged from a vessel operated at elevated temperature and pressure conditions, said apparatus comprising: means for receiving and conveying said mixture from said vessel, said means for receiving and conveying extending downwardly from said vessel, said means having upper and lower ends; means for selectively injecting gas into said means for receiving and conveying said mixture thereby stripping said particulates of entrained synthesis gas ... .
Background: Conventional systems for stripping and depressurizing a mixture of fine particulates mixed with gas, such as flyash mixed with synthetic gas, also referred to as syngas, from a vessel, such as a cyclone separator-stripper, operated at elevated temperature and pressure conditions usually employ either throttling valve or a lockhopper following the separator-stripper to equalize the pressure between the separator-stripper and a low pressure receiving vessel as the mixture is discharged from the separator-stripper.
However, pressure surges created by the lockhopper in communication with the separator-stripper decrease the removal efficiency of the separator-stripper due to elutriation and reentrainment of flyash from the bed of the separator-stripper back into the synthetic gas. Additionally, throttling valves are subject to rapid erosion.
The present invention is directed to overcoming these problems in the prior art.
Summary: The primary purpose of the present invention relates to stripping and depressurizing fine particulates mixed with gas discharged from a vessel operated at elevated temperature and pressure conditions. In particular, this invention relates to stripping and depressurizing flyash mixed with syngas produced by a coal gasification reactor, hereinafter referred to as a gasifier.
Generation of synthesis gas occurs by partially combusting carbonaceous fuel, such as coal, at relatively high temperatures in the range of 800-2000C and at a pressure range of from about 1-200 bar in the presence of oxygen or oxygen-containing gases in a gasifier.
Oxygen-containing gases include air, oxygen-enriched air, and oxygen optionally diluted with steam, carbon dioxide and/or nitrogen.
(We must emphasize, of course, that, as given short shrift above, but as more fully explained by Shell in:
Shell Oil Coal + CO2 + H2O = Hydrocarbon Syngas | Research & Development; concerning: "United States Patent 7,829,601 - Partial Oxidation Process of a Solid Carbonaceous Feed; 2010; Assignee: Shell Oil Company, Texas; Abstract: The invention is directed to a process for preparing a mixture comprising CO and H2 by operating a partial oxidation process of a solid carbonaceous feed which process comprises the steps of: (Supplying) the solid carbonaceous feed and an oxygen-containing stream to a burner, wherein a CO2 containing transport gas is used to transport the solid carbonaceous feed to the burner; (And) partially oxidizing the carbonaceous feed in the burner wherein a gaseous stream comprising CO and H2 is being discharged from said burner into a reaction zone, (and) wherein the solid carbonaceous feed is coal";
Carbon Dioxide, reclaimed from whatever source, can be utilized as one of the co-reactants, with Coal, in a process that generates a hydrocarbon synthesis gas "mixture comprising CO and H2".)
Gasification of coal produces a gas, known as synthesis gas or syngas, that contains mostly carbon monoxide and hydrogen. Also produced are varying quantities of ... small particles of ash and carbon commonly known and collectively defined herein as flyash or flyslag. This flyash, because it is derived from a "reducing" atmosphere, tends to be different in composition and properties from flyash normally associated with combustion boilers where a fully oxidizing atmosphere is utilized. For example, the flyash from the process for partially combusting coal may contain elemental iron, sulfides, and deposited carbon, components not normally associated with boiler flyash."
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We note that the potential for recovering worthwhile amounts of "iron", "elemental" or otherwise, from the inorganic remnants of Coal oxidation is one that has been addressed by others, since our above-referenced earlier report of:
Iowa Mines Metals from Coal Ash for the USDOE | Research & Development; also contains information concerning: "United States Patent 4,386,057 - Recovery of Iron Oxide from Coal Fly Ash; 1983; Assignee: The United States of America; The U.S. Government has rights in this invention pursuant to Contract No. W-7405-ENG-82 between the U.S. Department of Energy and Ames Laboratory; Abstract: A high quality iron oxide concentrate, suitable as a feed for blast and electric reduction furnaces is recovered from pulverized coal fly ash. The magnetic portion of the fly ash is separated and treated with a hot strong alkali solution which dissolves most of the silica and alumina in the fly ash, leaving a solid residue and forming a precipitate which is an acid soluble salt of aluminosilicate hydrate. The residue and precipitate are then treated with a strong mineral acid to dissolve the precipitate leaving a solid residue containing at least 90 weight percent iron oxide.This invention relates to a process for the recovery of iron from coal fly ash. More specifically, this invention relates to a process for recovering iron oxide, as a concentrate suitable for reduction, from pulverized coal fly ash";
also contains information disclosing how both elemental, or nearly elemental, i.e., "magnetic", Iron, and other Iron compounds, can be recovered in a practical way from Coal-derived "fly ash"; which Shell explains herein how to recover, as an integrated step in an overall process, that, as also explained by Shell, in their Disclosure of the above-cited "US Patent 4,218,388 - Preparing Hydrocarbons from Gasification of Coal", enables the production, from Coal, through an initial Coal gasification, of a "hydrocarbon mixture ... boiling in the gasoline range".