High pressure extraction

Abstract

A reactor system comprising two or more subterranean reactors for high pressure treatment of materials. The reactors each comprise an inlet tube, a reaction region and an outlet tube and are deep enough for material in the inlet and outlet tubes to produce significant hydrostatic pressure. The reactors are adapted to exchange heat which may occur through a shared heat transferring wall or a heat exchanger including circulating liquid. The invention also extends to a method of simultaneously running two processes in the reactor system. The preferred processes are hydrothermal dewatering of coal, especially brown coal, and coal liquefaction wherein exothermic heat product of one process contributes to the heating requirements of the other process. The invention also extends to a method of hydrothermal dewatering of coal when conducted in a subterranean reactor in conditions of decreasing pressure.

1 . A method of conducting two processes under pressurised conditions, said method comprising the steps of:
 introducing materials for a first process into a first reaction chamber located substantially underground and formed by a first downwardly extending inlet communicating with a first reaction zone, said first reaction zone communicating with a first upwardly extending outlet arrangement;   introducing further materials for a second process into a second reaction chamber located substantially underground and formed by a second downwardly extending inlet communicating with a second reaction zone, said second reaction zone communicating with a second upwardly extending outlet arrangement;   initiating the first and second processes; and   transferring heat between the first and second reaction chambers,   wherein one of said first and second processes is hydrothermal dewatering of coal.   
     
     
         2 . The method of  claim 1 , wherein the other of said first and second processes is coal liquefaction. 
     
     
         3 . The method of  claim 2 , wherein coal which has undergone hydrothermal dewatering in one of said processes is subject to liquefaction in the other of said processes. 
     
     
         4 . A method of hydrothermal dewatering of coal, said method comprising the steps of:
 delivering a coal slurry through one or more delivery tubes of an inlet of an underground reaction chamber to a reaction zone of the reaction chamber at a depth sufficient to generate pressure from a hydrostatic head;   raising the coal slurry from the reaction zone through one or more outlet tubes of an outlet of said reaction chamber to decrease pressure; and   initiating hydrothermal dewatering of the coal slurry such that hydrothermal dewatering substantially occurs in conditions of decreasing pressure during the raising step.   
     
     
         5 . The method of  claim 4 , further including the step of:
 maintaining an upward directed flow of the coal slurry substantially in the one or more outlet tubes throughout hydrothermal dewatering of the coal.   
     
     
         6 . The method of  claim 5 , wherein a velocity of the coal slurry is controlled by pump pressure. 
     
     
         7 . The method of  claim 4 , wherein a velocity of the coal slurry is in the range of 0.5 meter per second to 3 metres per second. 
     
     
         8 . The method of  claim 7 , wherein the velocity of the coal slurry is around 1 meter per second. 
     
     
         9 . The method of  claim 4 , wherein a concentration of coal in the slurry is selected to control the heat production of the reaction and thereby control the temperature in the reaction zone. 
     
     
         10 . The method of  claim 4 , wherein a concentration of as-mined coal in the slurry is between 40 weight-percent and 65 weight-percent. 
     
     
         11 . The method of  claim 10 , wherein the concentration of coal in the slurry is around 50 weight-percent. 
     
     
         12 . The method of  claim 4 , wherein the coal is brown coal.