We know we've beaten it to death, but, the inorganic mineral residues left behind by our use of the carbon content in Coal, for whatever purpose, constitute a valuable resource.
As we documented, for just one example, in our report of:
West Virginia Coal Association | Consol Converts Coal Ash to Concrete Aggregate | Research & Development; concerning: "United States Patent 5,364,572 - Process for Making High-Strength Synthetic Aggregates; 1994; Assignee: Consolidation Coal Company, Pittsburgh; Abstract: A process for making high-strength aggregates including hydrating calcium oxide containing coal combustion ash for a sufficient period of time to convert a high percentage of the calcium oxide to calcium hydroxide prior to forming the aggregates and curing the aggregates in high humidity. The moisture of the hydrated material is monitored to vary the hydration moisture to the desired set point. Further, the process involves producing high-strength aggregates from calcium hydroxide containing FGD ashes such as generated from duct sorbent injection and spray dryer processes. Method of producing high-strength aggregates from calcium oxide (CaO) containing coal combustion ash ...";
we can, among other things, consume Coal Ash in the manufacture of synthetic construction aggregates, for use, as a natural resource-sparing substitute for gravel or crushed stone, in structural Concrete.
Further, we can combine Coal Ash with other materials to make lightweight aggregates for specialty Concrete composite applications, as seen for one example in:
West Virginia Coal Association | Coal Ash and Sewer Sludge to Lightweight Concrete Aggregate | Research & Development; concerning: "United States Patent 5,342,442 - Lightweight Aggregate from Flyash and Sewage Sludge; 1994; Assignee: Wisconsin Electric Power Company, Milwaukee; Abstract: A method is shown for producing a lightweight aggregate by treating flyash and sewage sludge. A lightweight aggregate ... , said aggregate consisting essentially of a heat-hardened agglomerate of 35-80% by dry weight of flyash and 20-65% by dry weight of uncombusted sewage sludge and that has a hard and porous nodular structure (which) can be used as a lightweight aggregate for concretes, masonry, or insulation purposes".
As we've documented, there is no appreciable chemical difference in the mineral residues resulting from our combustion of Coal for the generation of economical electric power or from our conversion of Coal into hydrocarbons, whether directly, via solvent liquefaction, or indirectly, via gasification and subsequent catalytic chemical condensation.
That fact is borne out by the US Patent we bring to your attention herein, wherein it's confirmed that Ash resulting from the conversion of Coal into hydrocarbon synthesis gas can be utilized, as in our above citation of "United States Patent 5,342,442", as a raw material for the manufacture of lightweight aggregate.
As seen in excerpts from the initial link in this dispatch to:
"United States Patent 5,166,109 - Utilization of Slag from Coal Gasification Systems
Patent US5166109 - Utilization of slag from coal gasification systems - Google Patents
Utilization of slag from coal gasification systems - Electric Power Research Institute
Date: November, 1992
Inventors: Seymour Alpert, CA, and Donald Meisel, TX
Assignee: Electric Power Research Institute (EPRI), CA
(We've cited EPRI a number of times previously; and, they figure in reports to follow. More about them can be learned via:
Electric Power Research Institute - Wikipedia, the free encyclopedia; "The Electric Power Research Institute (EPRI) conducts research on issues related to the electric power industry in the USA. EPRI is a nonprofit organization funded by the electric utility industry. EPRI is primarily a US based organization, but receives international participation. EPRI's area covers different aspects of electric power generation, delivery and its use. Following Senate hearings in the early 1970s on the lack of R&D supporting the power industry, all sectors of the U.S. electricity industry pooled their funds to begin an industry-wide collaborative R&D program. EPRI was established in 1973 as the Electric Power Research Institute. Created as an independent, nonprofit organization designed to manage a broad public-private collaborative research program on behalf of the electric utility industry, the industry’s customers, and society at large, EPRI’s creation was a recognition of the impact of electricity on modern life".)
Abstract: A low density aggregate product and method for making the same utilizing coal ash slag resulting from a typical coal gasification system wherein the resulting aggregate product has a lower density than the initial coal ash slag. The coal ash slag is combined with a small amount of a binder and then fired for a predetermined time and temperature to produce the aggregate. Also, by heating the coal ash slag and binder, a gaseous efflux is emitted to form interlaced channels throughout the aggregate which have a characteristic length and diameter.
Claims: An aggregate useful as a structural material utilizing coal ash resulting from coal gasification, said aggregate produced by firing a mixture consisting of said coal ash slag and a binder and water for 4-10 minutes and at a temperature within the range of 1600 - 1900 F wherein said aggregate produced is less dense than said coal ash slag ... .
Background and Field: This invention relates to an aggregate and method for making the same which utilizes coal ash slag from coal gasification systems. More particularly, the present invention relates to a lightweight aggregate having a lesser density than the coal ash slag from which it was formed allowing for its use as a structural material. Further, the processed aggregate includes interlaced channels of characteristic diameter and length which allow for its use in chemical filtering or reaction processes.
Several coal gasification systems have been developed over the past decade.
(The decade prior to the 1992 issuance of this patent was a productive one for the development of Coal gasification, and follow-on, technologies. See, for instance, our report of:
West Virginia Coal Association | Conoco 1985 Coal to Gasoline & Methanol | Research & Development; concerning: "United States Patent 4,534,772 - Process of Ether Synthesis; Date: 1985; Assignee: Conoco Inc., DE; Abstract: A method for producing fuel comprised of gasoline rich in methanol and methyl ethers derived from coal, which process comprises gasifying the coal to produce carbon monoxide and hydrogen, steam shifting the gasification product to produce additional hydrogen, cleaning up the shifted product, catalytically converting the cleaned shifted gas to a mixture of alcohols, separating a methanol fraction from the mixture of alcohols, dehydrating the remaining alcohols to olefins, etherifying the olefin mixture with a portion of the removed methanol fraction, and blending into gasoline the resulting ether mixture and a second portion of the removed methanol fraction. Claims: A process for producing a high octane liquid gasoline fuel product mixture rich in methanol and methyl ethers from coal".)
These entrained coal gasification systems feature the partial combustion of coal using an oxidant resulting in the production of synthesis gas (syngas). To date, such systems have not generally been commercially attractive, because they have typically had higher operating costs than other existing conventional processes.
Specifically, in these processes all or substantially all of the carbon found in the coal is reacted at an elevated temperature and at an elevated pressure to form the desired syngas. Systems vary with respect to methods for feeding the coal; i.e., coal-water slurry systems and dry feed systems. In these systems the reaction temperature is above the melting point of the ash present in the coal fed to the system. Therefore, the ash is molten to allow the oxidant to react with the carboneous material.
When the desired reaction has occurred, typically, the flowing stream of gases and molten ash is rapidly cooled by quenching in a liquid pool of water. The slag produced by standard coal gasification systems has been shown to be relatively dense, impervious to leaching and relatively inert. The slag material is continuously removed from the system by equipment that permits an intermittent or continuous let down of the slag-water by-product from the elevated pressure of the particular system. Once removed, the slag must be disposed of in a safe and suitable manner. This step further adds to the total cost of producing syngas.
Summary: (It) is an object of the present invention to provide a lightweight aggregate and a method producing the same which will utilize coal ash slag resulting from coal gasification systems in a cost effective and simplistic manner.
Another object of the present invention is to provide a lightweight aggregate useful as a structural material which is produced by firing a mixture including a substantial amount of coal ash slag removed from a coal gasification system and a minor amount of a suitable binder wherein the aggregate produced has a density less than the component coal ash slag.
Still another object of the present invention is to provide a lightweight aggregate useful as a porous structure which is produced by firing a mixture including a substantial amount of coal ash slag removed from a coal gasification process and a minor amount of a suitable binder wherein the porous aggregate includes interlaced channels having a characteristic diameter and length.
Yet another object of the present invention is to provide a method for producing a lightweight aggregate useful as a structural material (from the) coal ash slag resulting from coal gasification wherein the aggregate produced is of a lesser density than the component coal ash slag, the method including the steps of screening the coal ash slag, recovering excess char from the screened coal ash, crushing the oversize particles removed by the screening process and re-combining the crushed particles with the slag mixing the slag with an appropriate amount of a binder slag, extruding or pelletizing the slag and binder to form a pre-aggregate, drying the pre-aggregate, firing the pre-aggregate and finally sealing the surface of the aggregate to form a final product.
These, as well as other advantages of the present invention, are achieved by combining glassy coal ash slag produced as a by-product from a standard coal gasification system with a binder. The binder may be a readily available clay, such as bentonite, present in the aggregate at approximately 2-10% of the mixture. The coal ash slag is processed through a series of steps which result in an aggregate which has a lesser density or weight than the original coal ash slag. The lower density allows for its use as a component in a number of structural materials such as mortar, cement, lightweight concrete blocks, etc."
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And, we submit that the "cement" in which this Coal gasification slag-based aggregate can be used could be that produced from even more Coal gasification and conversion slag, as in our report of:
West Virginia Coal Association | Standard Oil Converts Coal Conversion Residues into Cement | Research & Development; concerning: "United States Patent 4,174,974 - Process for Converting Coal Ash Slag into Portland Cement; 1979; Assignee: Standard Oil Company of Indiana; Abstract: Disclosed is a manufacturing process for converting coal ash slag from a slagging coal gasifier into a marketable cement product having the characteristics and qualities of portland cement".
As EPRI makes clear in the full Disclosure, though not well-reflected in our excerpts, the intent of the technology embodied in "United States Patent 5,166,109 - Utilization of Slag from Coal Gasification Systems" is to reduce the cost of "production of synthesis gas (syngas)" from Coal, so that the products which can subsequently be produced from that syngas, such as the "gasoline" and "methanol" of Conoco's "United States Patent 4,534,772 - Process of Ether Synthesis", as cited above, would be more competitive in cost with their petroleum-based counter parts.
Since we now know, as seen for only one example in:
West Virginia Coal Association | Iceland, August 2012, CO2 to Gasoline and Diesel | Research & Development; concerning: "US Patent Application 20120201717 - Process and System for Producing Liquid Fuel from CO2 and Water; 2012; Assignee: CRI, Iceland; A process and system for producing high octane fuel from carbon dioxide and water is disclosed. The feedstock for the production line is industrial carbon dioxide and water, which may be of lower quality. The end product can be high octane gasoline, high cetane diesel or other liquid hydrocarbon mixtures suitable for driving conventional combustion engines or hydrocarbons suitable for further industrial processing or commercial use";
that, we can also productively utilize any Carbon Dioxide byproduct which might arise from the type of Coal gasification discussed herein, as well, we wonder, with the two full decades of steady OPEC price gouging that's gone on since award of our subject, "United States Patent 5,166,109 - Utilization of Slag from Coal Gasification Systems", just how much more competitive in cost such processes would have to become, before they are finally deemed to be more economical than the total cost - - which cost must be calculated to include sending the occasional flotilla of armed forces to the Persian Gulf and sacrificing the lives of some number of young US citizens in uniform - - now required to keep the OPEC oil spigots open and flowing.