Fugitive methane emissions account for about 50% of the greenhouse gas (GHG) emissions from the Canadian conventional oil and gas sector. Sources include leaks in natural gas transmission facilities such as pipelines and compressor stations. There are three sources of methane emissions in a compressor station. The first is emissions resulting from incomplete combustion in the engine, the second is leaks in valves, flanges and other equipment in the building, and the third results from instrument venting. Because fugitive methane emissions are in low concentration relative to air, they cannot be destroyed by conventional combustion (below flammability limits of about 5% to 16%). The present study investigates catalytic combustion solutions for methane emissions in compressor stations. Computer modelling of the flow patterns of lean methane emissions inside the building is used to show the influence of doors, vents and leak location. Catalytic converter solutions are demonstrated for the destruction of the methane. For lean burn natural gas engines, effluent building air can be mixed with engine exhaust directly and/or instrument vent gas and fed to an appropriate catalytic converter. These reactors may be coupled to provide heat transfer to maintain the building air converter at reaction temperature. Simulations show that for a typical building most fugitive methane exits through the ridge vent provided that the main doors remain closed. Reverse flow reactors can readily be used to destroy lean methane mixtures available at ambient temperature.
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