Investigations of Catalytic Methane Oxidation under Lean Wet Exhaust Conditions

Abstract

This current research work has been focused on Methane (CH4) reduction in a Diesel Oxidation Catalyst (DOC) emitted from a Dual Fuel-Premixed Charged Compression Ignition (DF-PCCI) engine. This new alternative combustion technology is implemented on a Diesel Engine powered by both diesel fuel and natural gas in order to reduce diesel fuel usage and maintain the same thermal efficiency. However, the drawback lies in higher amount of CH4 in the exhaust that might effects Original Equipment Manufacturer (OEM)'s DOC performance. In this work, thermophysical and chemical properties of DF-PCCI exhaust such as temperature, flow rate, and specie concentrations are varied to investigate their effects on CH4 conversion efficiency in DOC. Design of Experiment (DOE) is built and tested in a Synthetic Exhaust Gas Generating System that can simulate the DF-PCCI exhaust-like conditions and all tested parameters are fully controlled. The experimental matrix is selected to cover DF-PCCI exhaust condition ranges to optimizing CH4 treatment. A kinetic model with water concentration is also investigated and compared to DOE model and experimental data. It is shown that the major factors that influence methane oxidation are exhaust flow rate, H2O concentration, and exhaust temperature (at P-value < 0.05 or at confidence level of 95%). The DOE model for predicting CH4 reductions is also generated.