Clean burning gas flare tip

Abstract

This disclosure presents a clean burning flare stack, or gas flare. The gas flare is air assisted to ensure clean burning. The disclosed gas flare provides smokeless clean burning of released gases. For example, the gas flare burns the released gases in a lean burning condition such that sufficient air is supplied to the surges of gases. In addition, the gas flare, by using a low pressure blower mixing chamber, is capable of handling low pressure gases and high pressure gases. As such, different flow rates may be provided to the gas flare when different amounts of low pressure and high pressure flammable gases are mixed with sufficient blower air to provide a clean burning condition. The disclosed smokeless gas flare is thus environmentally friendly and aesthetically appealing.

What is claimed is: 
     
         1 . A flare stack comprising:
 a base supplying flammable gases and blower air;   a tip receiving the flammable gases and the blower air, the tip having a mixing chamber and a gathering chamber;   a riser transferring a first portion of the flammable gases to the tip at a first pressure, the riser having a high pressure riser opening below an opening of the mixing chamber of the tip;   a first riser transferring a second portion of the flammable gases to the gathering chamber of the tip at a second pressure, the gathering chamber below the mixing chamber;   a second riser transferring the blower air to the low pressure blower mixing chamber of the tip; and   a plurality of low pressure risers extending from the gathering chamber into the mixing chamber, the plurality of low pressure risers having openings below the high pressure riser opening,   wherein the first pressure is greater than the second pressure.   
     
     
         2 . The flare stack of  claim 1 , wherein the base further comprises an air compressor configured to provide the blower air, the air compressor having a controller operable to provide the blower air at a flow rate that produces a lean burning condition when mixed with the flammable gases from both the riser and the plurality of low pressure risers up to a stoichiometric ratio, wherein the controller receives measurement signals from one or more sensors installed in the tip. 
     
     
         3 . The flare stack of  claim 1 , wherein the mixing chamber further includes:
 an inner core having a central tube and a flange extending radially from the central tube, and a plurality of surrounding tubes extending from the flange and substantially parallel to the central tube, wherein the central tube forms the at least one high pressure riser and the plurality of surrounding tubes forms the one or more low pressure risers; and   an external housing sealingly surrounding the inner core at the flange, wherein the blower inlet is an opening at the external housing, wherein the inner core further includes a plurality of straightening vanes radially extending from the central tube and dividing the plurality of surrounding tubes into individual risers with the external housing above the blower inlet.   
     
     
         4 . The flare stack of  claim 1 , wherein the base further includes one or more relief valves separating the first portion of the flammable gases from the second portion of the flammable gases. 
     
     
         5 . The flare stack of  claim 1 , further comprising a pilot shoot delivering a pilot gas to the tip, the pilot shoot providing an on-going flame for lighting up the flammable gases in the tip. 
     
     
         6 . A clean burning gas flare comprising:
 a mixing chamber having an opening;   a gathering chamber;   a flange positioned between the mixing chamber and the gathering chamber, the flange having a plurality of openings;   at least one high pressure riser having a high pressure gas opening positioned at least partly within the mixing chamber;   a plurality of low pressure risers in fluid communication with the gathering chamber extending from the openings of the flange, each low pressure riser having a low pressure gas opening positioned within the mixing chamber below the high pressure gas opening; and   an air riser in fluid communication with the mixing chamber through an air opening positioned below the low pressure gas openings and the high pressure gas opening.   
     
     
         7 . The clean burning gas flare of  claim 6 , wherein the high pressure gas opening is radially centered with respect to the opening of the mixing chamber and the low pressure gas openings are arranged radially around the high pressure gas opening. 
     
     
         8 . The clean burning gas flare of the  claim 6  further comprising:
 a side riser in fluid communication with the gathering chamber through a side riser opening. 
 
     
     
         9 . The clean burning gas flare of  claim 6  further comprising:
 a plurality of flame tabs extending radially inward from the opening of the mixing chamber. 
 
     
     
         10 . The clean burning gas flare of  claim 6  further comprising at least one straightening vane extending from an interior wall of the mixing chamber. 
     
     
         11 . The clean burning gas flare of  claim 10  wherein the at least one straightening vane is positioned above the low pressure gas openings and below the high pressure gas opening. 
     
     
         12 . The clean burning gas flare of  claim 10  wherein the at least one straightening vane is disposed over one of the low pressure gas openings. 
     
     
         13 . The clean burning gas flare of  claim 6  further comprising:
 a thermocouple positioned at an exit of the low pressure mixing chamber; 
 a thermocouple reader connected to the thermocouple and configured to transmit a temperature reading; and 
 an air flow rate controller configured to receive the temperature reading from the thermocouple reader and to adjust the air flow rate to achieve a calculated temperature.