Development of a Sulfur Tolerant PGM Based Zeolite Catalyst for Methane Oxidation and Low Temperature Hydrocarbon Trapping

摘要

With forthcoming 2014 EPA GHG legislation capping methane emissions at 0.10 g/bhp-hr for heavy-duty engines, development of a thermally stable and sulfur-tolerant methane oxidation catalyst becomes more critical. This is particularly true for natural gas-powered engines where methane slip is a significant contributor in the emissions and sulfur is present as a constituent of odorants used in CNG. Scientists at Clariant have recently developed a novel process for manufacturing a PGM containing zeolite that is both thermally stable and resistant to sulfur poisoning. Methane oxidation catalysts typically require temperatures in excess of 400°C to achieve light-off and are often sensitive to exposure to sulfur. The PGM zeolite catalyst has shown remarkable activity at low temperatures and a resistance to sulfur poisoning. Tests have shown that even after exposure to heavy concentrations of sulfur, the catalyst has little change in activity. In addition to methane oxidation, this catalyst has shown excellent hydrocarbon storage and oxidation activity at low temperatures. These properties allow this new material to be used in applications where cold-start emissions control is particularly important.