Microwave processing of oil shale and coal

Abstract

The present invention provides methods and systems for obtaining oil or a combustible gas from oil shale or coal, by subjecting oil shale or coal to microwave radiation for a time sufficient to at least partially decompose or extract oil, gas, or other carbon-containing materials from the oil shale and coal. The disclosed processes and systems use microwave radiation comprising at least one frequency component in the range of from about 4 GHz to about 18 GHz.

1 . A method for obtaining oil or a combustible gas from oil shale, comprising:
 subjecting oil shale comprising shale rock and kerogen to microwave radiation for a time sufficient to at least partially decompose said kerogen,   wherein said microwave radiation comprises at least one frequency component in the range of from about 4 GHz to about 18 GHz; and   recovering oil or a combustible gas from the decomposed kerogen.   
     
     
         2 . The method of  claim 1 , wherein the oil shale is subjected to microwave radiation at a pressure of less than one atmosphere. 
     
     
         3 . The method of  claim 2 , wherein the oil or a combustible gas is recovered from the decomposed kerogen at a pressure of less than one atmosphere. 
     
     
         4 . A method for obtaining a carbon-based material from coal, comprising:
 subjecting coal to microwave radiation for a time sufficient to at least partially decompose said coal, wherein the temperature of said coal does not exceed about 700° F.,   wherein said microwave radiation comprises at least one frequency component in the range of from about 4 GHz to about 18 GHz; and   recovering a carbon-based material from the decomposed coal.   
     
     
         5 . The method of  claim 4 , wherein the coal is subjected to microwave radiation at a pressure of less than one atmosphere. 
     
     
         6 . The method of  claim 4 , wherein the carbon-based material is recovered from the decomposed coal at a pressure of less than one atmosphere. 
     
     
         7 . The method of  claim 4 , wherein the carbon-based material is a hydrocarbon. 
     
     
         8 . The method of  claim 7 , wherein the hydrocarbon is oil or a combustible gas. 
     
     
         9 . A microwave system for processing coal, oil shale, or both, comprising:
 an infeed airlock configured to receive coal, oil shale, or both, said infeed airlock being sealable at a pressure less than one atmosphere, wherein said infeed airlock is configured to gravity feed coal, oil shale, or both into a microwave reactor coupled to said infeed airlock;   said microwave reactor being oriented to permit gravity-driven transport therethrough of coal, oil shale, or both;   said microwave reactor further comprising a microwave antenna orientable towards said coal, oil shale, or both, to irradiate said coal, oil shale, or both while being transported through the microwave reactor;   said microwave reactor further comprising a vacuum port to receive carbon-containing fluid generated from coal, oil shale, or both being irradiated with microwave radiation characterized as having at least one frequency component in the range of from about 4 GHz to about 18 GHz;   a microwave radiation generator operatively coupled to said microwave antenna via a microwave waveguide, wherein said microwave radiation generator is capable of generating microwave radiation characterized as having at least one frequency component in the range of from about 4 GHz to about 18 GHz;   a vacuum generator operatively coupled to said vacuum port, wherein said vacuum generator is capable of generating pressure within said microwave reactor below one atmosphere;   a vessel or conduit operatively coupled to said vacuum port to receive the carbon-containing fluid; and   a discharge airlock operatively coupled to the microwave reactor to receive microwave-processed coal, microwave-processed oil shale, or both from the microwave reactor, wherein said discharge airlock is capable of discharging the microwave-processed coal, the microwave-processed oil shale, or both, from the microwave system while maintaining pressure within the microwave reactor at less than one atmosphere.   
     
     
         10 . Oil produced by the method of  claim 1 . 
     
     
         11 . Oil produced by the method of  claim 4 . 
     
     
         12 . A combustible gas produced by the method of  claim 1 . 
     
     
         13 . A combustible gas produced by the method of  claim 4 .