A Method And Apparatus For Thermochemically Processing Material

Abstract

This invention relates to a method and apparatus for thermochemically processing material, and in particular relates to the torrefaction of organic material such as biomass, in particular to improve the energy content of the material, the method involving enclosing the material in a reactor which is then evacuated by means of a fluid driven vacuum pump to establish an oxygen free environment within the reactor, heating the material to above 200° C. to liberate process by-products such as volatile gases and/or oils, extracting the liberated volatile gases and/or oils from the enclosure and entraining same within the fluid driving the vacuum pump.

1 . A method of thermochemically processing a material comprising steps of:
 retaining the material in a fluid tight enclosure;   reducing the concentration of oxygen within the enclosure;   thermally liberating at least one substance from the material; and   extracting the at least one thermally liberated substance from the enclosure.   
     
     
         2 . A method according to  claim 1  comprising retaining the material, in a heated state, in the fluid tight enclosure. 
     
     
         3 . A method according to  claim 1  comprising heating the material of after retaining the material in the enclosure. 
     
     
         4 . A method according to  claim 3  comprising heating the material for a period of up to 100 minutes. 
     
     
         5 . A method according to  claim 1  comprising heating the material to a temperature above 40° C. 
     
     
         6 . A method according to  claim 1  comprising reducing oxygen concentration within the enclosure to below 20%. 
     
     
         7 . A method according to  claim 1  comprising thermochemically liberating the at least one substance from the material. 
     
     
         8 . A method according to  claim 1  comprising thermochemically liberating volatile gases and/or oils from the material. 
     
     
         9 . A method according to  claim 1  comprising the step of reducing moisture content of the material prior to heating the material. 
     
     
         10 . A method according to  claim 9  comprising reducing an equilibrium moisture content of the material to between 0-5%. 
     
     
         11 . A method according to  claim 1  comprising the step of at least partially evacuating the enclosure to reduce oxygen concentration. 
     
     
         12 . A method according to  claim 11  comprising at least partially evacuating the enclosure with a fluid driven vacuum pump. 
     
     
         13 . A method according to  claim 12  comprising passing a flow of fluid through a venturi in the vacuum pump to generate a reduction in pressure within the pump, and utilising the reduction in pressure to establish a negative pressure differential between the pump and the enclosure in order to at least partially evacuate the enclosure. 
     
     
         14 . A method according to  claim 13  comprising utilising the negative pressure differential between the pump and the enclosure in order to extract the at least one thermally liberated substance from the enclosure. 
     
     
         15 . A method according to  claim 14  comprising the step of entraining the at least one thermally liberated substance in the flow of fluid operating the vacuum pump. 
     
     
         16 . A method according to  claim 15  comprising separating liquid and gaseous phases from the fluid downstream of the vacuum pump. 
     
     
         17 . A method according to  claim 12  comprising heating the flow of fluid operating the vacuum pump. 
     
     
         18 . A method according  claim 12  comprising heating at least a part of the vacuum pump. 
     
     
         19 . A method according to  claim 12  comprising reclaiming heat from the fluid. 
     
     
         20 . A method according to  claim 1  comprising reclaiming heat from the thermochemically processed material. 
     
     
         21 . A method according to  claim 1  comprising utilising the at least one thermally liberated substance to heat the enclosure. 
     
     
         22 . A method according to  claim 1  comprising utilising the at least one thermally liberated substance to produce heat for the use in the method. 
     
     
         23 . A thermochemical processing apparatus comprising:
 a fluid tight enclosure for retaining a material to be thermally processed; and   a vacuum pump arranged to reduce the oxygen concentration within the enclosure.   
     
     
         24 . A thermochemical processing apparatus according to  claim 23  further comprising a heating system adapted to heat the enclosure. 
     
     
         25 . A thermochemical processing apparatus according to  claim 23  wherein the vacuum pump comprises a fluid driven vacuum pump. 
     
     
         26 . A thermochemical processing apparatus according to  claim 25  wherein the vacuum pump comprises a fluid jet eductor. 
     
     
         27 . A thermochemical processing apparatus according to  claim 25  further comprising a phase separation tank downstream of the fluid driven vacuum pump. 
     
     
         28 . A thermochemical processing apparatus according to  claim 27  further comprising a heat exchanger arranged to reclaim heat from the separation tank. 
     
     
         29 . A thermochemical processing apparatus according to  claim 23  further comprising a heat exchanger arranged to reclaim heat from the material. 
     
     
         30 . A thermochemically processed product produced according to the method of  claim 1 .