Abstract
The global warming problem might be the greatest threat ever to the future of mankind, and scientists have concluded that human activities are the main cause. Energy related activities are the major source of the greenhouse gas (GHG) emission, which enhance the global warming problem. Leaks in natural gas transmission facilities are the main sources of fugitive methane emissions. Unfortunately, these emissions are difficult to mitigate. Because of their low concentration, conventional combustion cannot destroy them. The present study aims at evaluating the possibility of using catalytic reactor to reduce fugitive methane emissions in the natural gas sector. The proposed reactor is a catalytic flow reversal reactor (CFRR), which has already been proved to work well with lean methane concentrations in coal mine. The natural gas compressor station is a major source of fugitive methane emissions, and it is a focus of this work. The fugitive methane has a lean methane concentration in atmospheric air. Thus, finding a means of concentrating the methane to meet CFRR feed quality is the initial task to be performed. Computer modelling of the flow patterns inside the building is used to show the influence of ventilation openings, ambient temperature and leak location. Simulations show that for a typical building most methane emitted inside will exit through the ridge vent provided the main doors remain closed. When the extraction rate through the ridge vent is controlled, the methane concentration can satisfy the CFRR feed quality. The CFRR performance was studied in some detail. Two catalysts are evaluated; one is a non-noble metal in the form of rashig rings in a packed bed, and the other a commercial Pd monolith. The activity of the Pd catalyst was studied and the feed and products influence, are reported. It is shown that the Pd catalyst is much more active than the non-noble metal one, and this has implications for reactor design. It is shown that the reactor insulation has a significant influence on reactor performance, especially for smaller diameter reactors. The correct combination of switch time and velocity is also important. Overall, it will be shown that this proposed technology offers promising results for methane emission abatement.