Session: 05-04: Methane Emissions Control

Paper Number: 110512

110512 - Advances in the Catalytic Oxidation of Methane Emitted From Natural Gas Engines 

The abundant domestic natural gas resources has motivated the accelerated development of natural gas powered vehicles and stationary engines.  With the primary constituent of abundant NG being methane (CH₄), NG has a higher H:C ratio than gasoline or diesel and therefore its combustion produces less CO₂.   However, CH₄ is itself a more potent greenhouse gas (GHG) than CO₂ with a GHG potential about 85 times that of CO₂. Uncombusted CH₄ must be eliminated in order to clear the way for the growth in the NG engine market. Current state-of-the-art Platinum Group Metal (PGM) catalysts are ineffective in eliminating methane. Our research is focused on the study and development of a new class of cost effective, structured catalysts with reduced PGM loadings for both stoichiometric and lean methane oxidation. For stoichiometric oxidation we show that the combination of spinel mixed metal oxide (AB₂O₄) addition and lean-rich feed modulation results in significant enhancement in the catalyst performance. Detailed study of feed modulation parameters (frequency, amplitude), catalyst design (composition, architecture) and spatiotemporal reactor features provide insight into and optimization of the underlying mechanism. The enhancement is attributed to the transient oxidation of methane conversion inhibitors CO and H₂ by the spinel. Up to a 30% reduction in PGM loading is possible with negligible loss in performance. For lean oxidation we study and develop an in situ method to regenerate methane oxidation catalysts. Periodic reductant (H₂, CO) pulsing mitigates the detrimental water poisoning of Pd-Pt catalyst. The pulsing is able to regenerate the catalyst deactivated by water by removal of OH-groups from the catalysts surface, but also promoted its activity after repeated application of pulsing for several hours. This state of high activity is stable for several hours under the tested lean conditions.

Presenting Author: Michael Harold University of Houston

Presenting Author Biography: Mike Harold is the Cullen Engineering Professor in the Department of Chemical and Biomolecular Engineering at the University of Houston. With expertise in catalysis and reaction engineering, Harold is the author of more than 185 peer-reviewed papers and book chapters and has given over 350 presentations and invited lectures. Harold received his BS at Penn State and PhD from the University of Houston (UH). He joined the faculty at University of Massachusetts at Amherst in 1985 where he became Associate Professor. In 1993 Harold joined DuPont Company, where he held technical and managerial positions. In 2000 Harold became the Dow Chair Professor and Department Chair at UH, a position he held for 16 years. Mike served as Editor-in-Chief of the AIChE Journal from 2012 through 2021. His honors include the Excellence in Applied Catalysis from the Southwest Catalysis Society in 2019, the Ester Farfel Award at UH in 2013, and AIChE Fellow in 2014.