Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3660054 A
Publication typeGrant
Publication dateMay 2, 1972
Filing dateSep 29, 1970
Priority dateSep 29, 1970
Publication numberUS 3660054 A, US 3660054A, US-A-3660054, US3660054 A, US3660054A
InventorsRieve Robert W
Original AssigneeAtlantic Richfield Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Coal upgrading
US 3660054 A
Abstract
A method for upgrading coal to a higher quality fuel or feed stock by mixing coal with water and heating the mixture in a non-oxidizing atmosphere at a temperature near the critical temperature of water and under a pressure sufficient to maintain substantially all of the water in the liquid state. By this process at least the sulfur and/or ash content of the coal is reduced.
Images(2)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

0 United States Patent 1151 3,660,054 Rieve [4 1 Ma 2 1972 [s4] COAL UPGRADING 3,249,402 5/1966 Smyers et 81.... ..23/224 [72] Inventor: Robert W. Rieve, Springfield, Pa. FOREIGN PATENTS 0R APPLICATIONS [731 Assigne= z z Rlchfield CmPanY, New Yrk1 747,730 4/1956 Great Britain ..44/4

22 Filed; s 29, 1970 Primary Examiner-C. F. Dees A I N 76 601 Attorney-Blucher S. Tharp and Roderick -W. MacDonald pp 0.: v

[57] ABSTRACT [52] U.S. Cl. "sl t/l R A method for upgrading l to a higher quality fuel or feed [5 4 22 stock by mixing coal with water and heating the mixture in a [5 1 o arc non-oxidizing atmosphere at a temperature near the critical 5 6 R temperature of water and under a pressure sufiicient to main- 1 e erences l e tain substantially all of the water in the liquid state. By this UNITED STATES PATENTS process at least the sulfur and/or ash content of the coal is reduced. 51,231 11/1865 Smith ..44/1R 2,726,148 12/1955 McKinley et a] 4 Claims, No Drawings BACKGROUND OF THE INVENTION Heretofore coal has been extensively used as a fuel for the generation of electricity, and the like and has also been employed as the feed stock in processes for its conversion to gaseous and liquid hydrocarbonaceous products from which fuel gas, gasoline, residual fuel oil, and the like can be obtained. One process utilizing coal as a feedstock is the hydrogenation of coal to gasify and liquify same, a particularly suitable process being that disclosed by U.S. Pat. No. Re. 25,770, the disclosure of which is incorporated herein by reference.

It is highly desirable for evironmental purposes to reduce the-sulfur and ash content of any coal utilized as a fuel or as a feed stock for a process which produces a fuel. Although sulfur reduction can take place during the treatment of a coal feed stock to convert the coal into a liquid or gaseous product from which fuels can be obtained and although it is possible to reduce the sulfur and ash content of stack gases after the'coal or fuel product obtained therefrom has been burned, it is most desirable to reduce the content of these materials in the coal initially. This is desirable because it renders the conditions of subsequent burning or processing of the coal more flexible since they do not have to provide extensive sulfur and ash treating facilities at each location.

Accordingly, it is very desirable to be able to substantially reduce at least the sulfur and/or ash content of a coal before it is burned as a fuel or otherwise gasified and/or liquified for further processing into specific fuels.

SUMMARY OF THE INVENTION It has now been found that if coal is mixed with water and heated in a non-oxidizing atmosphere at a temperature near the critical temperature of water, but not above the critical temperature of water, at least the sulfur and/or ash content of that coal is reduced. I

. Accordingly, it is an object of this invention to provide a new and improved process for upgrading coal. It is another object to provide a new and improved process for the removal of at least a portion of at least one of sulfur and'ash from raw coal. It is another object to provide a new and improved method for rendering a raw coal more acceptable as a fuel or feed stock for further processing into a fuel.

Other aspects, objects, and advantages of this invention will be apparent to those skilled in the art from this disclosure and the appended claims.

DETAILED DESCRIPTION OF THE INVENTION According to this invention a coal, which can be one or a mixture of two or more of anthracite, bituminous, semi-bituminous, sub-bituminous, lignite, peat, and the like, is subdivided, for example so that substantially all of the coal particles are no larger than one inch in their largest cross-sectional dimension (effective diameter), and mixed with water.

The mixing can be carried out in any desired manner so long as an intimate mixture of coal particles and water is achieved and can be conducted at sub-ambient, ambient, or super-ambient conditions of temperature and pressure. Preferably, the coal and water are simply mixed together at ambient conditions of temperature and pressure. The mixture is preferably composed of coal and water in the weight ratio range of coal/water of from about 2 to about 0. 1.

The mixture is then heated in a non-oxidizing atmosphere, e.g., steam, inert gas, reducing gas, and the like, at a tempera ture of from about 600 F to about the critical temperature of water, i'.e., 706 F. Although a broad temperature range of from about 600 to about 706 F. can be employed, a presently preferred range is from about650 to about 706 F. It is important that the temperature of the water during the reaction be near but not above the'critical temperature so that the water will be more monomeric than polymeric and more adidic than normal. It is also important that the water not be in the vaporous state to any substantial extent. The pressure should be maintained sufficiently elevated so that substantially all of the water will be maintained in a liquid state at the temperature prevailing. The pressure therefore can be the autogenous pressure of water vapor at the temperature of reac-- tion and will generally range from about 1,545 to about 3,226 p.s.i.a.

By following the above conditions substantial amounts of sulfur and/or ash can be removed from the coal. The reaction should therefore be carried out for a time sufficient to achieve these results. This time will generally be at least about one minute, preferably at least'about five minutes, e.g., from about five minutes to about sixty minutes.

The coal, after completion of the reaction time, can be recovered with or separate from the water present in the reaction. The recovered coal can be utilized, either with or without and liquifaction process.

EXAMPLE Pittsburg No. 8 seam coal subdivided so that substantially all passes a l00 mesh sieve and is retained on a 200 mesh sieve (Tyler) was mixed with water in a weight ratio of coal/water of 0.25 by simple stirring at ambient conditions of temperature, pressure and under one atmosphere of nitrogen to provide an intimate mixture of the coal particles and water.

The mixture was then heated in an autoclave at 650 F. under an autogenous pressure of 2,350 p.s.i.g. for 1 hour after which the autoclave was vented to the atmosphere and most of the water thereby expelled.

The standard coal analysis for the coal before and I after treatment was as follows:

Analysis,

Wt. MAF

Coal Raw Coal Treated Coal Carbon 76.16 80.77 Hydrogen 5.21 4.76 Oxygen 5.96 5.49 Nitrogen 1.55 1.61 Sulfur 2.74 1.27 Ash 8.38 6.10 Volatile Matter 7 39.06 33.66, Fixed Carbon 52.56 60.24

It can be seen from the above data that the sulfur content was reduced by 53.6 percent and that the ash was also reduced by 27.3 percent. With such a substantial reduction in both sulfur and ash content, the treated coal was a much more acceptable burning fuel and liquid fuel feed stock since it would introduce substantially less sulfur and ash into the combustion products or other liquid and gas products obtained therefrom.

Reasonable variations and modifications are possible within the scope of this disclosure without departing from the spirit and scope of this invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for upgrading coal comprising mixing subdivided coal and water in the weight ratio range of coal/water of from about 2 to about 0. l heating said mixture in a nonoxidizing atmosphere at a temperature of from about 600 to about 706 F., said heating being under a pressure sufficient to maintain substantially all of the water in the liquid state and for a time sufficient to reduce at least one of the sulfur and ash con tent of said coal, and recovering the treated coal.

2. A method according to claim 1 wherein said pressure is in the range offrom about 1,545 to about 3,226 p.s.i.a.

3. A method according to claim 1 wherein said coal is subdivided to be substantially all no greater than about 1 inch effective diameter particles.

4. A method according to claim 1 wherein said coal is at least one of bituminous and lignite and is subdivided to be substantially all no greater than about 1 inch effect diameter particles, said temperature is from about 650 to about 706 F., and said time is for at least about 1 minute.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US51231 *Nov 28, 1865 Improvement in treating peat
US2726148 *Jun 9, 1950Dec 6, 1955Gulf Research Development CoProduction of low sulfur solid carbonaceous fuels
US3249402 *Oct 2, 1962May 3, 1966Exxon Research Engineering CoRecovery of sulfur from blast furnace slag
GB747730A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4018571 *Feb 20, 1975Apr 19, 1977Texaco Inc.Treatment of solid fuels
US4047898 *Oct 28, 1976Sep 13, 1977Texaco Inc.Upgrading of solid fuels
US4052169 *Feb 20, 1975Oct 4, 1977Texaco Inc.Treatment of solid fuels
US4057399 *Mar 7, 1975Nov 8, 1977Texaco Inc.Process for dewatering carbonaceous materials
US4058976 *Nov 21, 1975Nov 22, 1977Encotech, Inc.Method and apparatus for removal of last traces of soluble ash and elements from solvent refined coal
US4098583 *Mar 17, 1977Jul 4, 1978Firma Carl Still RecklinghausenGrinding, suspension in water, fusion
US4104035 *Dec 11, 1975Aug 1, 1978Texaco Inc.For production of synthesis gas
US4364740 *May 7, 1981Dec 21, 1982Cng Research CompanyMethod for removing undesired components from coal
US4377392 *Aug 24, 1981Mar 22, 1983Cng Research CompanyParticles from explosive comminution
US4405332 *Jul 28, 1981Sep 20, 1983Rodriguez Larry AAlternative fuel comprised of sewage sludge and a particulate solid fuel
US4441886 *Nov 22, 1982Apr 10, 1984Southern Illinois University FoundationTreatment with ethanol at elevated temperature and pressure
US4516980 *Jun 20, 1983May 14, 1985Iowa State University Research Foundation, Inc.Process for producing low-ash, low-sulfur coal
US4762527 *Dec 16, 1986Aug 9, 1988Electric Fuels CorporationSlurry fuel comprised of a heat treated, partially dewatered sludge with a particulate solid fuel and its method of manufacture
US5080692 *Nov 13, 1989Jan 14, 1992The University Of AkronRemoval with water, methanol, and carbon dioxide solvent
US7383766Aug 26, 2002Jun 10, 2008Mte Research Pty LtdCoal dewatering system and method
DE2526923A1 *Jun 16, 1975Jan 8, 1976Shell Int ResearchVerfahren zur aufbereitung von gebundenes wasser und freien oder chemisch gebundenen kohlenstoff enthaltendem festen material und insbesondere von braunkohle
DE2654626A1 *Dec 2, 1976Jun 16, 1977Texaco Development CorpVerfahren zur aufbereitung einer schlaemme aus festem brennstoff und wasser
EP0026011A1 *Aug 27, 1980Apr 1, 1981Shell Internationale Research Maatschappij B.V.Process for the upgrading of low-grade solid fuel
EP1427795A1 *Aug 26, 2002Jun 16, 2004Generation Technology Research Pty LtdCoal dewatering system and method
Classifications
U.S. Classification44/500, 44/624, 44/627, 208/403, 44/608
International ClassificationC10L9/00
Cooperative ClassificationC10L9/00
European ClassificationC10L9/00