Process gas abatement

Abstract

A process gas abatement apparatus and method are disclosed. The process gas abatement apparatus comprises: a burner comprising: a combustion chamber operable to receive an effluent gas stream from a manufacturing process tool to be treated within the combustion chamber at a sub-atmospheric pressure, the combustion chamber being further operable to receive a fuel, oxidant and diluent, the fuel, oxidant and diluent controlling combustion within the combustion chamber to treat the effluent gas stream to produce a treated exhaust stream, the diluent being condensable in the treated exhaust stream. By providing a diluent in the form of, for example, an inert condensable, the volume gain within the combustion chamber is reduced, which reduces the volume of the exhaust stream and reduces the volumetric load on the second pump. The volume gain reduces because the diluent shifts phase in the exhaust stream, thereby effectively removing the contribution of the diluent to the volume of the exhaust stream. This leads to considerable power saving since a lower volume of gas is output from the combustion chamber which would need to be brought up to the second pressure, for example atmospheric pressure, by means of the second pump.

1 . A process gas abatement apparatus comprising:
 a burner, and   a combustion chamber operable to receive an effluent gas stream from a manufacturing process tool to be treated within the combustion chamber at a sub-atmospheric pressure, the combustion chamber being further operable to receive a fuel, oxidant and diluent, the fuel, oxidant and diluent controlling combustion within the combustion chamber to treat the effluent gas stream to produce a treated exhaust stream, the diluent being condensable in the treated exhaust stream.   
     
     
         2 . The process gas abatement apparatus of  claim 1 , wherein the diluent, when introduced to the combustion chamber, comprises a vapor. 
     
     
         3 . The process gas abatement apparatus of  claim 1 , wherein the diluent comprises a liquid prior to being vaporised for introduction to the combustion chamber. 
     
     
         4 . The process gas abatement apparatus of  claim 1 , wherein the diluent condenses to a liquid in the treated exhaust stream. 
     
     
         5 . The process gas abatement apparatus of  claim 1  wherein the diluent is introduced into the combustion chamber with a first volumetric rate and occupies the treated exhaust stream with a second volumetric rate, the second volumetric rate being lower than the first volumetric rate. 
     
     
         6 . The process gas abatement apparatus of  claim 1 , wherein the diluent is combined with at least one of the fuel and oxidant prior to being introduced into the combustion chamber. 
     
     
         7 . The process gas abatement apparatus of  claim 1 , wherein at least one of the fuel and the oxidant is dissolved by the diluent prior to being introduced into the combustion chamber. 
     
     
         8 . The process gas abatement apparatus of  claim 1 , wherein both the fuel and the oxidant are dissolved by the diluent prior to being introduced into the combustion chamber. 
     
     
         9 . The process gas abatement apparatus of  claim 1 , wherein at least one of the fuel and the oxidant dissolved by the diluent is vaporised prior to being introduced into the combustion chamber. 
     
     
         10 . The process gas abatement apparatus of  claim 1 , wherein at least one of the fuel and the oxidant dissolved by the diluent are co-vaporised prior to being introduced into the combustion chamber. 
     
     
         11 . The process gas abatement apparatus of  claim 1 , wherein the diluent comprises at least one of water, a perfluorocarbon and a hydrocarbon. 
     
     
         12 . The process gas abatement apparatus of  claim 1 , wherein the treated exhaust stream is provided to a liquid ring pump for compression to atmospheric pressure. 
     
     
         13 . The process gas abatement apparatus of  claim 12 , wherein the diluent condenses in the liquid ring pump. 
     
     
         14 . The process gas abatement apparatus of  claim 12 , wherein the liquid ring pump is operable to scrub the treated exhaust stream. 
     
     
         15 . A process gas abatement method, comprising:
 receiving an effluent gas stream to be treated from a manufacturing process tool within a combustion chamber at a sub-atmospheric pressure;   receiving a fuel, oxidant and diluent within the combustion chamber, the fuel, oxidant and diluent controlling combustion within the combustion chamber to treat the effluent gas stream to produce a treated exhaust stream; and   condensing the diluent in the treated exhaust stream.