Vacuum-assisted bulk material treatment

Abstract

A bulk material comprising at least one substance to be removed from the bulk material is treated. The method includes introducing the bulk material into a heating chamber. The heating chamber is in a partial vacuum. The method further includes heating the bulk material in the heating chamber and in the presence of the partial vacuum to cause the at least one substance to vaporize. The method further includes extracting the bulk material, with the at least one vaporized substance separated therefrom, from the heating chamber.

1 . A method of treating a bulk material comprising at least one substance to be removed from the bulk material, comprising:
 introducing the bulk material into a heating chamber, wherein the heating chamber is in a partial vacuum;   heating the bulk material in the heating chamber and in the presence of the partial vacuum to cause the at least one substance to vaporize; and   extracting the bulk material, with the at least one vaporized substance separated therefrom, from the heating chamber.   
     
     
         2 . The method of  claim 1 , wherein the bulk material comprises soil. 
     
     
         3 . The method of  claim 1 , wherein the at least one substance comprises a contaminant. 
     
     
         4 . The method of  claim 2 , wherein the contaminant comprises at least one hydrocarbon. 
     
     
         5 . The method of  claim 1 , wherein the at least one substance comprises water. 
     
     
         6 . The method of  claim 1 , wherein the heating chamber at a pressure of 10-20 kPa. 
     
     
         7 . The method of  claim 1 , wherein introducing the bulk material into the heating chamber comprises:
 loading the bulk material into an airlock;   with the bulk material in the airlock, generating a partial vacuum in the airlock; and   transferring the bulk material from the airlock to the heating chamber.   
     
     
         8 . The method of  claim 1 , wherein heating the bulk material comprises heating the bulk material using electric heating. 
     
     
         9 . The method of  claim 8 , wherein heating the bulk material comprises heating the bulk material using inductive heating. 
     
     
         10 . The method of  claim 1 , further comprising condensing the at least one vaporized substance. 
     
     
         11 . The method of  claim 10 , wherein condensing the at least one vaporized substance comprises:
 transferring the at least one vaporized substance from the heating chamber to a cooling structure; and   condensing the at least one vaporized substance on the cooling structure.   
     
     
         12 . The method of  claim 11 , wherein the cooling structure comprises at least one cooling plate over which a coolant is flowed, or a heat exchanger comprising one or more conduits through which a coolant is flowed. 
     
     
         13 . The method of  claim 1 , wherein:
 the at least one vaporized substance comprises at least one vaporized contaminant;   the method further comprises:   condensing the at least one vaporized contaminant into a condensate on a cooling plate on which is flowing a coolant; and   separating the condensate into: the condensed contaminant; the coolant; and particulate matter entrained in the condensate.   
     
     
         14 . The method of  claim 12 , wherein the coolant is water. 
     
     
         15 . The method of  claim 12 , wherein the method further comprises:
 cooling at least some of the coolant; and   recirculating the cooled coolant to the cooling plate.   
     
     
         16 . A thermal desorption system for treating a bulk material comprising at least one substance to be removed, comprising:
 an airlock for receiving the bulk material;   a heating chamber connected to the airlock;   a condensing chamber;   one or more vacuum pumps for generating a partial vacuum in the airlock and the heating chamber;   one or more heaters in the heating chamber for heating the bulk material when the bulk material has entered the heating chamber from the airlock to cause the at least one substance to vaporize; and   one or more vapor ducts positioned to direct the at least one vaporized substance from the heating chamber to the condensing chamber,   wherein, by causing the at least one substance to vaporize, the one or more heaters are configured to cause a pressure in the heating chamber to be higher than a pressure in the condensing chamber and thereby produce a pressure differential to passively transfer the at least one vaporized substance from the heating chamber to the condensing chamber via the one or more vapor ducts.   
     
     
         17 . The thermal desorption system of  claim 16 , further comprising one or more controllers comprising circuitry and configured to:
 activate the one or more vacuum pumps to generate the partial vacuum in the airlock and the heating chamber;   operate the airlock to transfer the bulk material from the airlock to the heating chamber;   activate the one or more heaters to heat the bulk material when the bulk material has entered the heating chamber from the airlock, and cause the at least one substance to vaporize; and   extract the bulk material, with the at least one vaporized substance separated therefrom, from the heating chamber.   
     
     
         18 . The thermal desorption system of  claim 16 , wherein the one or more heaters comprise one or more inductive heaters. 
     
     
         19 . The thermal desorption system of  claim 16 , further comprising:
 one or more conveyors in the heating chamber positioned to receive the bulk material from the airlock and to transport the bulk material to an outlet of the heating chamber.   
     
     
         20 . The thermal desorption system of  claim 16 , wherein:
 the thermal desorption system further comprises a housing at least partially defining the heating chamber; and   the airlock extends through the housing and comprises a drum that is rotatable between:
 an open position in which an opening in the drum is open to an exterior of the thermal desorption system such that the bulk material may be loaded into the drum; and 
 a closed position in which the opening is positioned to permit the loaded bulk material to enter the heating chamber. 
   
     
     
         21 . The thermal desorption system of  claim 16 , further comprising:
 a condensing chamber comprising a cooling structure for condensing, into a condensate, the at least one vaporized substance that has flowed from the heating chamber to the condensing chamber.   
     
     
         22 . The thermal desorption system of  claim 21 , wherein the cooling structure comprises at least one cooling plate over which a coolant is to be flowed, or a heat exchanger comprising one or more conduits through which a coolant is to be flowed. 
     
     
         23 . (canceled) 
     
     
         24 . The thermal desorption system of  claim 21 , further comprising one or more duct heaters for heating the one or more vapor ducts. 
     
     
         25 . The thermal desorption system of  claim 20 , wherein the cooling structure comprises at least one cooling plate, and wherein the thermal desorption system further comprises:
 a coolant recirculation system for flowing a coolant over the at least one cooling plate; and   a decanter for separating the condensate into the at least one condensed substance and coolant that has flowed over the at least one cooling plate,   wherein the coolant recirculation system is configured to recirculate the separated coolant to the at least one cooling plate.   
     
     
         26 . The thermal desorption system of  claim 16 , wherein the one or more conveyors comprise at least one scraper conveyor. 
     
     
         27 . The thermal desorption system of  claim 16 , wherein the pressure differential mediates the passive transfer of the at least one vaporized substance from the heating chamber to the condensing chamber without the at least one vaporized substance being routed through a pump.