Hybrid Flare Apparatus

Abstract

A hybrid flare assembly for waste gas combustion includes a shell having an exhaust portion extending from an offset portion, and an ignitor for igniting the waste gas. The ignitor and support shaft longitudinal moves within the exhaust portion which is attached to the offset portion at an acute angle. Pluralities of risers are arrayed about the ignitor shaft for conducting gas from first and second high pressure inlets to a combustion chamber. A second shell partially defines a first chamber through which low pressure gas conducts and a second chamber separated from the first chamber by a perforated support plate through which high pressure gas conducts into the first plurality of risers. A method of combusting waste gas includes the steps of conducting a first high pressure gas flow to the first plurality of risers and conducting a second high pressure gas flow to the second plurality of risers.

What is claimed: 
     
         1 . A hybrid flare assembly for waste gas combustion, comprising:
 a shell defining a duct, the shell including an exhaust portion extending from an offset portion; and   an ignitor for igniting the waste gas, the ignitor mounted to a shaft for longitudinal movement within the exhaust portion, wherein an angle between longitudinally extending lines of the exhaust portion and the offset portion is acute.   
     
     
         2 . The hybrid flare assembly of  claim 1 , wherein the longitudinal movement of the ignitor and shaft occurs at least partially within a guide tube extending substantially along a centerline of the exhaust portion. 
     
     
         3 . The hybrid flare assembly of  claim 1 , wherein the exhaust portion of the shell partially defines a combustion chamber and the ignitor is supported within the combustion chamber. 
     
     
         4 . The hybrid flare assembly of  claim 1 , wherein the shell further includes an input portion extending from the offset portion. 
     
     
         5 . The hybrid flare assembly of  claim 1 , further comprising a flare stack attached to the shell, wherein the flare stack and the exhaust portion are substantially parallel. 
     
     
         6 . The hybrid flare assembly of  claim 1 , further comprising a first plurality of risers at least partially arrayed about the ignitor shaft for conducting high pressure gas from a first high pressure inlet to a combustion chamber partially defined by the exhaust portion of the shell. 
     
     
         7 . The hybrid flare assembly of  claim 6 , further comprising a second shell partially defining a first chamber through which low pressure gas conducts and a second chamber separated from the first chamber by a support plate having a plurality of holes formed therein through which high pressure gas conducts into the first plurality of risers. 
     
     
         8 . The hybrid flare assembly of  claim 7 , further comprising a guide tube within which the ignitor and the ignitor shaft move, wherein the guide tube extends longitudinally within and through the second chamber of the second shell. 
     
     
         9 . The hybrid flare assembly of  claim 3 , further comprising a shield attached to the shell and partially defining the combustion chamber. 
     
     
         10 . The hybrid flare assembly of  claim 9 , wherein an upper edge of the shield extends above an upper edge of the exhaust portion. 
     
     
         11 . The hybrid flare assembly of  claim 6 , further comprising a second plurality of risers at least partially arrayed about the first plurality of risers for conducting high pressure gas from a second high pressure inlet to the combustion chamber. 
     
     
         12 . The hybrid flare assembly of  claim 11 , further comprising a manifold for conducting high pressure gas from the second high pressure inlet to each of the second plurality of risers. 
     
     
         13 . The hybrid flare assembly of  claim 11 , further comprising a shield attached to the shell and partially defining the combustion chamber. 
     
     
         14 . The hybrid flare assembly of  claim 13 , wherein an upper edge of the shield extends above an upper edge of the exhaust portion. 
     
     
         15 . A hybrid flare assembly for waste gas combustion, comprising:
 a shell defining a duct, the shell including an exhaust portion extending from an offset portion;   an ignitor for igniting the waste gas, the ignitor mounted to a shaft for longitudinal movement within the exhaust portion; and   a first plurality of risers at least partially arrayed about the ignitor shaft for conducting high pressure gas from a first high pressure inlet to a combustion chamber.   
     
     
         16 . The hybrid flare assembly of  claim 15 , wherein the exhaust portion of the shell partially defines the combustion chamber and the ignitor is supported within the combustion chamber. 
     
     
         17 . The hybrid flare assembly of  claim 15 , further comprising a flare stack attached to the shell. 
     
     
         18 . The hybrid flare assembly of  claim 15 , further comprising a guide tube within which the ignitor and the ignitor shaft move. 
     
     
         19 . The hybrid flare assembly of  claim 15 , further comprising a shield attached to the shell and partially defining the combustion chamber. 
     
     
         20 . The hybrid flare assembly of  claim 15 , further comprising a first plurality of risers at least partially arrayed about the ignitor shaft for conducting high pressure gas from a first high pressure inlet to a combustion chamber. 
     
     
         21 . The hybrid flare assembly of  claim 20 , further comprising a second shell partially defining a first chamber through which low pressure gas conducts and a second chamber separated from the first chamber by a support plate having a plurality of holes formed therein through which high pressure gas conducts into the first plurality of risers. 
     
     
         22 . The hybrid flare assembly of  claim 20 , further comprising a manifold for conducting high pressure gas from a second high pressure inlet through a second plurality of risers to the combustion chamber. 
     
     
         23 . A hybrid flare assembly for waste gas combustion, comprising:
 a flare stack;   a shell attached to and extending from the flare stack, defining a duct, and including an offset portion and an exhaust portion;   an ignitor for igniting the waste gas, the ignitor mounted to a shaft for longitudinal movement within the exhaust portion of the shell; and   a first plurality of risers at least partially arrayed about the ignitor shaft for conducting a first gas flow from a first inlet to a combustion chamber.   
     
     
         24 . The hybrid flare assembly of  claim 23 , further comprising a manifold for conducting a second gas flow from a second inlet through a second plurality of risers at least partially arrayed about the ignitor shaft to the combustion chamber. 
     
     
         25 . The hybrid flare assembly of  claim 24 , further comprising a common manifold for receiving a common waste gas stream, and first and second valves for controllably releasing the first gas flow to the first inlet and the second gas flow to the second inlet. 
     
     
         26 . The hybrid flare assembly of  claim 23 , wherein the flare stack and the exhaust portion are substantially parallel and the intermediate portion is angled relative to the exhaust portion. 
     
     
         27 . The hybrid flare assembly of  claim 23 , further comprising a second shell partially defining a first chamber through which a third gas flow conducts and a second chamber separated from the first chamber by a perforated support plate through which the second gas flow conducts into the first plurality of risers. 
     
     
         28 . The hybrid flare assembly of  claim 23 , wherein the exhaust portion of the shell partially defines the combustion chamber and the ignitor is centrally supported within the combustion chamber. 
     
     
         29 . The hybrid flare assembly of  claim 27 , further comprising a shield attached to the shell and partially defining the combustion chamber. 
     
     
         30 . A method of combusting waste gas by a flare, comprising the steps of:
 conducting a low pressure gas flow from a low pressure gas inlet to a combustion chamber;   conducting a first high pressure gas flow from a first high pressure gas inlet to a first plurality of risers at least partially arrayed about an ignitor shaft;   conducting a second high pressure gas flow from a second high pressure gas inlet to a second plurality of risers at least partially arrayed about the first plurality of risers and the ignitor shaft to the combustion chamber;   mixing the low pressure gas flow, and the first and second high pressure gas flows with an air flow; and   combusting the mixed low pressure gas flow, the first and second high pressure gas flows, and the air flow within the combustion chamber.   
     
     
         31 . The method of combusting waste gas by a flare of  claim 30 , wherein the step of conducting a second high pressure gas flow is performed only when a measured gas flow rate or pressure exceeds a first threshold. 
     
     
         32 . The method of combusting waste gas by a flare of  claim 30 , wherein the step of conducting a second high pressure gas flow is discontinued when a measured gas flow rate or pressure falls below a second threshold. 
     
     
         33 . The method of combusting waste gas by a flare of  claim 30 , wherein the step of conducting a low pressure gas flow from a low pressure gas inlet to a combustion chamber includes the step of conducting the low pressure gas from the low pressure gas inlet, through a shell defining a duct, and to the combustion chamber. 
     
     
         34 . The method of combusting waste gas by a flare of  claim 33 , wherein the shell includes an exhaust portion extending from an offset portion, and the first and second plurality of risers are at least partially contained within the exhaust portion of the shell. 
     
     
         35 . The method of combusting waste gas by a flare of  claim 33 , wherein the shell includes an exhaust portion attached to an offset portion at an angle sufficient to allow a retractable ignitor to move longitudinally within an interior of the exhaust portion. 
     
     
         36 . The method of combusting waste gas by a flare of  claim 30 , further including the step of controllably releasing the first high pressure gas flow and the second high pressure gas flow from a common manifold receiving a common waste gas stream dependent upon a pressure or flow rate.