Apparatus and method for minimizing smoke formation in a flaring stack

Abstract

An apparatus and method for minimizing smoke formation in the operation of a flaring stack. The apparatus includes a generally annular gas deflector having an outer surface for deflecting the waste gas therealong. A plurality of lobes extend radially from the deflector to provide improved mixing between the waste gas and combustion air during combustion to reduce smoke formation.

1 . A method for combusting a waste gas to reduce the formation of smoke, the method comprising:
 passing the waste gas along an outer surface of a generally annular gas deflector including a plurality of lobes extending radially from an outer surface thereof;   drawing ambient air toward the outer surface for mixing with the waste gas; and   igniting the waste gas.   
     
     
         2 . The method of  claim 1 , wherein passing the waste gas along the outer surface includes passing the waste gas over a plurality of circumferentially spaced generally vertical ribs extending radially from the outer surface. 
     
     
         3 . The method of  claim 2 , further comprising passing the waste gas through channels between the vertical ribs. 
     
     
         4 . The method of  claim 3 , further comprising passing the waste gas along inclined sidewall surfaces extending from the channels to rib top portions. 
     
     
         5 . The method of  claim 1 , further comprising passing the waste gas over a Coanda surface of the gas deflector. 
     
     
         6 . The method of  claim 5 , wherein passing the waste gas over the Coanda surface includes passing the waste gas over a plurality of circumferentially spaced generally vertical ribs extending radially from the Coanda surface. 
     
     
         7 . The method of  claim 5 , further comprising passing the waste gas over a lower unribbed portion of the Coanda surface and then over an upper ribbed portion of the Coanda surface. 
     
     
         8 . The method of  claim 1 , wherein passing the waste gas over the outer surface includes passing the waste gas over an outer surface having a ratio of a perimeter of a ribbed portion of the gas deflector to an outer diameter of the ribbed portion of the gas deflector of between about 6.5 and about 20. 
     
     
         9 . The method of  claim 1 , wherein passing the waste gas over the outer surface includes passing the waste gas over an outer surface having a ratio of a perimeter of a ribbed portion of the gas deflector to an outer diameter of the ribbed portion of the gas deflector of between about 7.5 and about 16. 
     
     
         10 . A method for combusting a waste gas to reduce the formation of smoke, the method comprising:
 passing a waste gas through an inner passageway of a support arm;   passing the waste gas through an annular gas passage between the support arm and a generally annular gas deflector;   passing the waste gas along an outer surface of the gas deflector and over lobes extending radially from the annular gas deflector; and   igniting the waste gas.   
     
     
         11 . The method of  claim 10 , further comprising drawing ambient air toward the gas deflector to mix with the waste gas and reduce smoke formation during combustion of the waste gas. 
     
     
         12 . The method of  claim 10 , wherein the gas deflector includes a generally tulip- shaped Coanda bowl and passing the waste gas along the outer surface includes passing the waste gas over a Coanda surface of the Coanda bowl. 
     
     
         13 . The method of  claim 10 , further comprising shifting the gas deflector from a lower seated position to an raised open position to provide the annular opening to allow the waste gas to pass through the annular opening. 
     
     
         14 . The method of  claim 13 , further comprising shifting the gas deflector from the raised open position to the lower seated position to close the annular opening. 
     
     
         15 . The method of  claim 14 , wherein shifting the gas deflector to the lower seated position includes contacting a smooth un-ribbed seating portion of the gas deflector with an upper seating portion of the support arm to provide generally close contact therebetween. 
     
     
         16 . The method of  claim 14 , wherein shifting the gas deflector from the raised open position to the lowered closed position includes biasing the gas deflector toward the lowered position with a spring and reducing a waste gas pressure in the waste gas passageway.