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 . An apparatus for minimizing the formation of smoke in the operation of a flaring stack, the apparatus comprising:
 a generally annular gas deflector having an outer surface for deflecting waste gas therealong;   a plurality of lobes extending generally radially from the deflector outer surface for providing improved mixing between the waste gas and combustion air during combustion.   
     
     
         2 . The apparatus of  claim 1 , wherein the lobes include circumferentially spaced generally vertical ribs extending radially from the outer surface of the gas deflector. 
     
     
         3 . The apparatus of  claim 2 , wherein a ratio of a perimeter of a ribbed portion of the bowl to an outer diameter of the ribbed portion is between about 6.5 and about 20. 
     
     
         4 . The apparatus of  claim 2 , wherein the gas deflector includes a tulip-shaped bowl having a Coanda surface. 
     
     
         5 . The apparatus of  claim 4 , wherein the ribs extend radially from an upper portion of the bowl above a convex portion of the Coanda surface. 
     
     
         6 . The apparatus of  claim 5 , wherein an intermediate convex portion of the bowl is generally smooth and free of ribs. 
     
     
         7 . The apparatus of  claim 4 , wherein the ribs extend generally vertically from an upper portion of the bowl into at least a portion of an intermediate convex portion of the bowl. 
     
     
         8 . The apparatus of  claim 1 , wherein the ribs are tapered radially with respect to the outer surface from a generally lower rib portion flush with the outer surface to a raised rib portion above the outer surface. 
     
     
         9 . The apparatus of  claim 1 , wherein the ribs include inclined sidewalls extending from channels between the ribs to rib top portions. 
     
     
         10 . The apparatus of  claim 1 , wherein a ratio of a combined circumferential width of the one or more ribs to a combined circumferential width of a plurality of channels between the ribs is between about 0.5 and about 5. 
     
     
         11 . The apparatus of  claim 1 , wherein the ribs have a ratio of a rib radial height above a channel floor to an outer radius of the gas deflector of between about 0.01 and about 0.2. 
     
     
         12 . An apparatus for minimizing the formation of smoke in the operation of a flaring stack, the apparatus comprising:
 a support arm having a generally hollow waste gas passageway for connection to a waste gas source;   a generally annular gas deflector having an outer surface for deflecting the waste gas therealong;   a waste gas outlet between the gas deflector and the support arm; and   a plurality of lobes extending generally radially from the gas deflector outer surface for providing improved mixing between the waste gas and combustion air during combustion.   
     
     
         13 . The apparatus of  claim 12 , wherein the gas deflector includes a Coanda bowl and the outlet includes an annular opening between an upper seating portion of the support arm and a Coanda surface of the Coanda bowl. 
     
     
         14 . The apparatus of  claim 13 , further comprising a shiftable connection between the Coanda bowl and the support arm so that the Coanda bowl is shiftable between a seated position, wherein Coanda bowl is supported by the upper seating portion and a raised position, wherein the Coanda bowl is raised from the upper seating portion to form the annular opening between the upper seating portion and the Coanda surface of the Coanda bowl. 
     
     
         15 . The apparatus of  claim 14 , wherein the shiftable connection includes a spring configured to bias the Coanda bowl to the lowered seated position. 
     
     
         16 . The apparatus of  claim 15 , wherein a seating portion of the Coanda bowl is free of ribs to form a smooth fit between the Coanda bowl seating portion and the support arm seating portion with the Coanda bowl in the seated position. 
     
     
         17 . The apparatus of  claim 13 , wherein the plurality of lobes includes circumferentially spaced generally vertical ribs extending radially from the outer surface of the Coanda bowl. 
     
     
         18 . The apparatus of  claim 13 , wherein the ratio of a perimeter of a ribbed portion of the Coanda bowl to an outer diameter of the ribbed portion is between about 7.5 and about 16. 
     
     
         19 . The apparatus of  claim 13 , comprising a plenum, a plurality of support arms extending from the plenum, a plurality of corresponding gas deflectors with annular openings between the plurality of support arms and plurality of corresponding gas deflectors, and a plurality of lobes extending radially from the plurality of gas deflectors.