Solvent treatment of coal for improved liquefaction

Abstract

Increased liquefaction yield is obtained by pretreating a slurry of solid carbonaceous material and a liquid hydrocarbonaceous solvent at a temperature above 200° C. but below 350° C. for a period of 10 minutes to four hours prior to exposure to liquefaction temperatures.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. In a solvation method for the liquefaction of carbonaceous material wherein the material is contacted with a hydrocarbonaceous liquid solvent in the presence of a source of hydrogen gas in a single liquefaction stage at a liquefaction temperature of at least 350° C. for a period of about 5 to 30 minutes, and a portion of the liquefaction product from the liquefaction stage is recycled for use as at least a portion of the liquid solvent, the improvement comprising: pretreating said carbonaceous material in contact with the hydrocarbonaceous liquid solvent in a preheater stage at a temperature of at least about 200° C. but not more than about 350° C. for a period of ten minutes to four hours to allow swelling of the carbonaceous material and penetration of the pore structure of the carbonaceous material with the hydrocarbonaceous liquid solvent prior to application of hydrogen gas and exposure to temperatures in excess of 350° C. in the presence of the hydrocarbonaceous liquid solvent in the liquefaction stage, said solvent is selected from the group consisting of hydrogenated creosote oil, SRC-II heavy distillate, 1-methylnaphthalene, and quinoline. 
     
     
       2. The method according to claim 1, wherein the liquefaction is conducted at a temperature of 350 ° C. to 475° C. and under a pressure of 1000 psig to 2500 psig. 
     
     
       3. The method according to claim 1, wherein the carbonaceous material is heated in contact with the liquid solvent to a temperature of about 200° C. to 300° C. for approximately 1 hour. 
     
     
       4. The method according to claim 1, wherein the hydrocarbonaceous liquid solvent and the carbonaceous material in powdered form are mixed together to form a slurry, the ratio by weight of hydrocarbonaceous liquid solvent to carbonaceous material being about 5:1. 
     
     
       5. In a solvation method for the liquefaction of a solid carbonaceous material wherein the material is heated in slurry with a hydrocarbonaceous liquid solvent a source of hydrogen gas in a single liquefaction stage at a liquefaction temperature of 350° to 475° C. for a period of about 5 to 30 minutes to form a liquefaction product, and a portion of the liquefaction product is recycled as at least a portion of the hydrocarbonaceous liquid solvent, the improvement comprising: pretreating the slurry of the carbonaceous material and the hydrocarbonaceous liquid solvent at a temperature of at least about 200° C. but not more than about 350° C. for a period of ten minutes to four hours and with a weight ratio of solvent to carbonaceous material of 1:1 to 5:1 to allow swelling of the carbonaceous material and penetration of the pore structure of the carbonaceous material with the hydrocarbonaceous liquid solvent prior to application of hydrogen gas and exposure to temperatures in excess of 350° C. in the presence of hydrocarbonaceous liquid solvent in the liquefaction stage, said solvent is selected from the group consisting of hydrogenated creosote oil, SRC-II heavy distillate, 1-methylnaphthalene, and quinoline.