Thermodynamic evaluation of a conceptual framework for methane mitigation

Abstract

In light of the Paris Agreement, the significance of deploying net-negative emission technologies has emerged. However, the scale at which these technologies are predicted to be rolled out is thought to be extremely optimistic, and deeper emissions reductions are needed if the target is to be achieved. Methane is a potent greenhouse gas, therefore a conceptual framework consisting of methane capture and combustion pathways is constructed and effectiveness cross-compared. A thermodynamic approach is employed to assess the exergy required by the process and capacity for avoided emissions. By the direct capture and storage of methane from a coal mine ventilation air emissions source, the exergy required is determined to be 376.73 kJ/kgCO2 equivalent of avoided emissions. Furthermore, emissions from the power source driving the process is account for and the overall emissions for this pathway amounts to 131 kgCO2 equivalent emitted per ton avoided. These values are moderately high compared to current values for CO2 capture thus future optimizing the process for minimum work while is crucial for its successful implementation.