Gasification and/or Pyrolysis

Abstract

The present invention provides a method and apparatus for gasifying/pyrolysing material containing organic matter including introducing the material into a treatment chamber ( 2 ) and heating the material by passing a flow of hot gas ( 30 ) containing less than 8% oxygen through the chamber ( 2 ) so as to cause the material therein to gasify or pyrolyse. In a first mode of operation the gas ( 30 ) is passed through the chamber ( 2 ) at a first velocity. The apparatus comprises a means ( 20, 21 ) for temporarily increasing the velocity of the hot gas ( 30 ) such that in a second mode of operation the velocity of the gas ( 30 ) exiting the means ( 20, 21 ) is temporarily increased.

1 . A method of gasifying and/or pyrolysing material containing organic matter, the method comprising:
 introducing said material into a treatment chamber;   heating said material by passing a flow of hot gas containing less than 8% oxygen by volume through said chamber so as to cause the material therein to pyrolyse or gasify;   in a first mode of operation the gas is passed through the chamber at a first velocity;   providing a means for temporarily increasing the velocity of the hot gas; and   in a second mode of operation, temporarily increasing the velocity of the gas.   
     
     
         2 . The method according to  claim 1  wherein providing a means for temporarily increasing the velocity of the gas comprises:
 providing a reservoir vessel for the hot gas upstream of the treatment chamber; 
 filling the reservoir vessel with hot gas at a first rate; and ejecting the hot gas from the reservoir at a second rate greater than the first rate. 
 
     
     
         3 . The method according to  claim 2  wherein the method comprises
 providing a reservoir vessel having a piston therein and an actuator for driving said piston and wherein 
 ejecting the hot gas comprises activating said actuator so as to move the piston to force hot gas from the reservoir vessel. 
 
     
     
         4 . The method according to  claim 3  wherein the vessel has an inlet and an outlet on either side of said piston, the method comprising opening one inlet on one side of the piston and opening one outlet on the opposite side of said piston; and in the first mode of operation moving said piston so that the instantaneous volumetric flow rate of the gas passing through the inlet is substantially equal to the instantaneous volumetric flow rate passing through the outlet. 
     
     
         5 . The method according to  claim 4  wherein in the second mode of operation the piston is moved at a speed greater than in the first mode of operation so as to force the air from the vessel through the outlet. 
     
     
         6 . The method according to  claim 5  wherein said piston is moved in a series of steps so as to provide a pulsed flow of hot gas through the outlet. 
     
     
         7 . The method according to  claim 3  wherein the vessel has an inlet and an outlet on either side of said piston, the method comprising, in a further mode of operation: opening the inlet and the outlet on the same side of the piston so as to provide a through flow through the vessel on one side of the piston. 
     
     
         8 . The method according to  claim 1  wherein the gas entering the processing chamber comprises less than 1% oxygen by volume and the material is pyrolysed. 
     
     
         9 . An apparatus for gasifying and/or pyrolysing material containing organic matter, the apparatus comprising:
 a processing chamber for receiving material to be gassified;   a processing chamber inlet for receiving hot gas;   a processing chamber outlet for exhausting hot gas; and   means for, in use, temporarily increasing the velocity of hot gas flowing into the inlet from a first velocity to a second higher velocity.   
     
     
         10 . The apparatus according to  claim 9  wherein said means for temporarily increasing the velocity of hot gas comprises:
 a reservoir chamber forming a cylinder and having a piston therein dividing the reservoir chamber into a first section and a second section; 
 at least one reservoir inlet and at least one reservoir outlet; 
 a drive means connected to said piston configured to drive said piston in said chamber; and 
 a control means configured to control said drive means to selectively drive said piston in said reservoir so as to expel hot gas from said reservoir in an accelerated manner. 
 
     
     
         11 . The apparatus according to  claim 10  further comprising a first inlet and a first outlet in said reservoir chamber on one side of said piston and a second inlet and a second outlet in said reservoir chamber on the other side of said piston; and wherein the control means is configured to, in a first drive direction close the first outlet and the second inlet and operate the drive means so as to move the piston from the first inlet towards the second outlet so that hot gas flows into the first section and out of the second section. 
     
     
         12 . The apparatus according to  claim 11  wherein the control means is configured to, in a second drive direction open the first outlet and the second inlet, and close the first inlet and second outlet, and operate the drive means so as to move the piston from the second inlet towards the first outlet so that hot gas flows into the second section and out of the first section. 
     
     
         13 . The apparatus according to  claim 11  wherein, in a first mode of operation the controller is configured to operate the drive means to move the piston at a speed such that the instantaneous flow rate of the gas expelled from the reservoir is substantially equal to the instantaneous flow rate of the gas entering the reservoir. 
     
     
         14 . The apparatus according to  claim 13  wherein, in a second mode of operation the controller is configured to operate the drive means to move the piston at a speed such that the instantaneous flow rate of the gas expelled from the reservoir is greater than the instantaneous flow rate of the gas entering the reservoir. 
     
     
         15 . The apparatus according to  claim 14  wherein, in the second mode of operation the controller is configured to operate the drive means in a plurality of discreet steps such that the gas expelled from the reservoir is expelled in a plurality of accelerated bursts of gas.