Pilot scale assessment of methane capture from low concentration sources to town gas specification by pressure vacuum swing adsorption (PVSA)

Methane (CH4) is the second largest contributor to anthropogenic greenhouse gas (GHG) emissions. The separation of CH4 from nitrogen (N-2) is crucial for the capture of CH4 from low concentration sources, such as coal seam gas, to reduce GHG emissions. Pressure vacuum swing adsorption (PVSA) provides a flexible and scalable method for CH4/N-2 separation. In this work, a novel adsorbent (ILZ) was used in a 112 kg scale PVSA pilot facility to test the feasibility of separating CH4 from low concentration sources (4.7-44.5%). A product purity of 44.5% CH4 and a methane recovery of 81% were achieved from a feed gas containing just 4.7% CH4 via a 3-stage PVSA process. Such a product gas can then be transported using pipelines and used for either power generation or 4T town gases in China. The total energy consumption was 133 kJ per mol CH4 captured, which is 85% lower than its heating value (similar to 880 kJ/mol). This study demonstrates that the capture of CH4 from large but low concentration sources incentivises GHG emissions reduction.