METHANE SLIP EMISSION TREATMENT BY PT/PD/AL263 WASHCOATED MONOLITH WITH SPATIAL CONCENTRATION MEASUREMENTS

摘要

Advances in drilling technology have led to low-price domestic natural gas, increasing the economic incentive for natural gas powered engines. Increased utilization of natural gas to power vehicles in the form of compressed natural gas (CNG) and liquefied natural gas (LNG) has already begun and is expected to accelerate. Natural gas vehicles typically have lower emissions of particulate matter (PM), NO_x and SO_x, especially compared to older diesel powered vehicles. Engine exhaust emissions of non-methane hydrocarbons (NMHCs) and CO are treated by catalytic oxidation on precious metal catalysts. The oxidation catalysts are particularly effective for lean burn vehicles which have excess O2 in the exhaust. However, with the primary component of natural gas being methane (CH4), a small but significant amount of CH4 fuel survives the combustion chamber and "slips" into the exhaust. With global warming potential approximately 20 times that of CO2, CH4 is a potent greenhouse gas (GHG), and regulations are expected to become more stringent. For this reason, development of CHt oxidation catalysts and emission control systems are needed. The objective of this study is to carry out a detailed experimental study of CH4 oxidation on supported Pt/Pd catalysts, which have been reported to be the most effective catalysts developed to date.