Dual-Pressure Flare System and Method of Use

Abstract

A dual-pressure flare system and a method of its use. The dual-pressure flare system includes a dual-pressure flare stack having a central axis that is aligned with the center of a high-pressure outlet; a high-pressure flue having a central axis that is co-linear with the central axis of the dual-pressure flare stack; and a low-pressure flue connected to a low-pressure tip. Some exemplary embodiments of the system further include an air-assist assembly having an air-supply connection connected to an air blower and a mixing chamber, wherein the mixing chamber surrounds the low-pressure tip. In some exemplary embodiments, the air-supply connection is disposed outside the dual-pressure flare stack and the high-pressure flue.

What is claimed is: 
     
         1 . A dual-pressure flare system comprising:
 (a) a dual-pressure flare stack comprising a central axis, a high-pressure chamber having a high-pressure gas inlet, a high-pressure gas outlet, and a center aligned with the central axis, and a low-pressure chamber having a low-pressure gas inlet and a low-pressure gas outlet, the low-pressure chamber in vertically stacked arrangement to the high-pressure chamber;   (b) a high-pressure flue comprising a central axis that is co-linear with the central axis of the dual-pressure flare stack, a first end connected to the high-pressure gas outlet, a second end connected to a high-pressure tip; and   (c) a low-pressure flue comprising a first end connected to the low-pressure gas outlet, a second end connected to a low-pressure tip.   
     
     
         2 . The system of  claim 1  wherein the high-pressure gas outlet inner diameter is smaller than the dual-pressure flare stack inner diameter by about 33% to about 66%. 
     
     
         3 . The system of  claim 1  wherein the high-pressure flue further comprises a transition narrowing its inner diameter by about 25% to about 50%. 
     
     
         4 . The system of  claim 1  wherein the high-pressure tip comprises at least one opening, wherein the opening diameter is smaller than the high-pressure tip inner diameter by about 25% to about 50%. 
     
     
         5 . The system of  claim 1  wherein the LP outlet is about 25% to about 50% narrower than the HP outlet. 
     
     
         6 . The system of  claim 1  wherein the low-pressure flue further comprises a transition narrowing its inner diameter by about 25% to about 50%. 
     
     
         7 . The system of  claim 1  wherein the low-pressure tip comprises at least one opening, wherein the opening diameter is smaller than the low-pressure tip inner diameter by about 25% to about 50%. 
     
     
         8 . The system of  claim 1  wherein the high-pressure gas inlet comprises an opening operable to induce a vortical flow of the high-pressure gas. 
     
     
         9 . The system of  claim 1  wherein the low-pressure gas inlet comprises an opening operable to induce a vortical flow of the low-pressure gas. 
     
     
         10 . The system of  claim 1  further comprising an air-assist assembly comprising an air-supply connection having a first end connected to an air blower and a second end connected to a mixing chamber, wherein the mixing chamber surrounds the low-pressure tip. 
     
     
         11 . The system of  claim 10  wherein the air-supply connection is disposed outside the dual-pressure flare stack and the high-pressure flue. 
     
     
         12 . The system of  claim 10  wherein the air-supply connection is connected to the high-pressure flue with a plurality of support brackets. 
     
     
         13 . The system of  claim 10  wherein the low-pressure tip opening is oriented in a direction of a flow of assist air. 
     
     
         14 . The system of  claim 1  further comprising a pilot light assembly. 
     
     
         15 . The system of  claim 14  wherein the pilot assembly further comprises a pilot igniter and a pilot guide rail, wherein the pilot guide rail is connected to high-pressure flue with a plurality of support brackets, wherein the pilot igniter is elevated inside the pilot guide rail with a pilot winch, wherein pilot igniter is connected to a pilot gas supply hose. 
     
     
         16 . The system of  claim 1  further comprising a flame hood surrounding the high-pressure tip and the mixing chamber. 
     
     
         17 . The system of  claim 16  wherein flame hood comprises a plurality of flame hood air holes. 
     
     
         18 . The system of  claim 16  wherein flame hood comprises a pilot light pipe. 
     
     
         19 . The system of  claim 1  further comprising a liquid evacuation system. 
     
     
         20 . The system of  claim 1  further comprising a supply gas tank having an inlet and a plurality of outlets, wherein outlets are connected to a control supply line, a pilot gas supply line, and a supply gas tank pressure relief line. 
     
     
         21 . The system of  claim 1  further comprising a flame arrestor. 
     
     
         22 . A method of operating a dual-pressure flare wherein the dual flare system comprises a dual-pressure flare stack having a high-pressure gas chamber in vertically-stacked relation to a low-pressure gas chamber, a high-pressure flue exiting from the high-pressure gas chamber, a low-pressure flue exiting from the low-pressure gas chamber, an air-assist assembly, a pilot assembly, and remote control panel; the method comprising:
 (a) flowing high-pressure gas into an inlet of the high-pressure chamber;   (b) flowing low-pressure gas into an inlet of the low-pressure chamber;   (c) inducing vortical flow in a high-pressure gas stream in the high-pressure chamber and in a low-pressure gas stream in the low-pressure chamber;   (d) removing entrained liquid from the low-pressure gas stream in the low-pressure chamber and from the high-pressure gas stream in the high-pressure chamber;   (e) expelling the high-pressure gas stream to flow vertically up from the high-pressure chamber in the high-pressure flue, and expelling the low-pressure gas stream to flow vertically up from the low-pressure chamber in the low-pressure flue;   (f) mixing assist-air to the low-pressure gas stream in the low-pressure flue near a low-pressure tip;   (g) igniting a pilot light using the pilot assembly, if the pilot light is not already lit; and   (h) combusting the high-pressure gas stream and the low-pressure gas stream exiting their respective flues at a hydrocarbon destruction and removal efficiency of at least 98 percent.   
     
     
         23 . The method of  claim 22  further comprising accelerating a flow rate of the high-pressure gas in the high-pressure gas stream in the high pressure flue. 
     
     
         24 . The method of  claim 22  further comprising accelerating a flow rate of the low-pressure gas in the low-pressure gas stream in the low-pressure flue. 
     
     
         25 . The method of  claim 22  further comprising evacuating the liquid from the dual-pressure flare system using a liquid evacuation system. 
     
     
         26 . The method of  claim 22  further comprising monitoring presence of the pilot light using a pilot sensor. 
     
     
         27 . The method of  claim 26  further comprising the remote control panel receiving a signal from pilot sensor, determining whether the signal indicates a pilot failure, and activating a pilot failure alarm. 
     
     
         28 . The method of  claim 22  further comprising monitoring the operation of the air-assist assembly using an air blower sensor. 
     
     
         29 . The method of  claim 28  further comprising the remote control panel receiving a signal from the air blower sensor, determining whether the signal indicates an air blower failure, and activating an air blower failure alarm. 
     
     
         30 . The method of  claim 22  wherein the step of combusting further comprises combusting at a sound level of from 90 to about 116 decibels.