Biochemically reacting substrates in subterranean cavities
AssigneeHouston Industries Incorporated
InventorsWilliam M. Menger, Ernest E. Kern, Kermit Allen, O. C. Karkalits, Donald L. Wise, Alfred P. Leuschner
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Abstract
A method for carrying out a biochemical reaction with a culture of microorganisms is performed in a cavity formed in a subterranean formation to produce combustible hydrocarbon gases. The method is especially suitable for the conversion of alkali-oxidized or hydrolyzed coal, such as lignite, to methane. The method may be performed in the cavity as a continuously stirred tank reaction, or plug flow or as a staged reaction. The method may also be done as an anaerobic fixed film process using particles as an anaerobic filter, as a sludge blanket, or as an expanded bed process.
Claims8
A method for biochemically converting coal to combustible hydrocarbon gases, comprising the steps of:
- (a) treating the coal by contacting the coal in a finely divided state with a hot aqueous alkali solution at a temperature of from about 150.degree. C. to about 300.degree. C. to produce an aqueous mixture of low molecular weight organics;
- (b) feeding the organic solution or mixture into a subterranean cavity;
- (c) inoculating the organic solution or mixture with a methanogenic microorganism culture;
- (d) maintaining the inoculated organic solution or mixture in the cavity at a pH between about 6.5 and about 8.5 and at a temperature between about 10.degree. C. and about 60.degree. C.;
- (e) allowing the microorganisms to grow in the organic solution or mixture in the cavity to produce methane;
- and
- (f) recovering the produced combustible hydrocarbon gases from the cavity.
Dependencies are inferred from the claim text.