Method and apparatus for oxidizing dried low rank coal
AssigneeAtlantic Richfield Company
InventorDonald K. Wunderlich
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Abstract
An apparatus for partially oxidizing dried low rank coal, the apparatus comprising a vessel in which the coal is supported and contacted with a free-oxygen-containing gas. A method for partially oxidizing the coal is also disclosed.
Claims6
An apparatus for partially oxidizing a dried particulate low rank coal to reduce the tendency of said dried particulate low rank coal to spontaneously ignite, said apparatus comprising:
- a. an oxidizer vessel, having an upper and a lower end;
- b. a particulate coal inlet in said upper end of said oxidizer vessel;
- c. a distributor means positioned in said vessel to distribute said particulate coal from said particulate coal inlet uniformly in said vessel;
- d. a grate means positioned in said lower end of said vessel for supporting said particulate coal in said vessel;
- and removing controlled quantities of oxidized particulate coal from said lower end of said vessel so that said particulate coal moves relatively uniformly downwardly through said oxidizer vessel;
- f. an air inlet means positioned in said lower end of said vessel for the injection of air into said particulate coal;
- and,
- g. an air outlet means positioned in said upper end of said vessel.
A method for partially oxidizing a particulate low rank coal selected from the group consisting of sub-bituminous, lignite and brown coals to reduce the tendency of said particulate low rank coal to spontaneously ignite, said method consisting essentially of:
- a. drying said particulate low rank coal to a water content from about 1 to about 5 weight percent greater than the water content desired in the dried oxidized low rank coal to produce a partially dried coal;
- b. charging said partially dried coal to a coal oxidation zone;
- c. contacting said partially dried coal with a free-oxygen containing gas in said coal oxidation zone at a temperature from about 175.degree. to about 225.degree. F. for a time sufficient to result in the reaction of from about 6 to about 25 lbs. of oxygen per ton of partially dried coal with said partially dried coal to produce a dried, oxidized coal;
- and,
- d. recovering said dried oxidized coal.
Dependencies are inferred from the claim text.