Methane: Valuable Feedstock or Greenhouse Gas? Catalytic Reaction Engineering Solutions in the Quest to Reform or Combust

ABSTRACT

Methane is the primary feedstock for hydrogen production, accomplished by catalytic steam methane reforming (SMR). But methane is also a potent greenhouse gas (GHG), so its emission to the atmosphere must be minimized by catalytic methane oxidation. In this talk, I will describe three catalytic reaction engineering solutions that address current challenges in methane conversion and abatement. Electrified SMR: Joule heating of catalysts supported on metallic substrates is shown to enhance the methane conversion rate. Using Ni/ZrO2-coated FeCrAl wire as the model catalyst, high methane conversion is achieved and for a range of conditions exceeds that obtained by conventional heating. The findings suggest an electrocatalytic mechanism is responsible. Potential reactor designs that enable distributed syngas production with renewable electricity are described. Methane Oxidation: More active catalysts are needed to oxidize methane in the exhaust of natural gas engines and vehicles. We describe experimental and modeling studies of lean and rich methane oxidation on Pt/Pd/Al2O3 coated monoliths. Steady state experiments under rich conditions show evidence of rate multiplicity and co-existing, spatially nonuniform states. Feed modulation experiments under net rich and lean condition reveal rate enhancement. We discuss the implications of and the underlying kinetic and transport mechanisms responsible for these interesting effects. Methane Oxidative Bi-Reforming: Coupled methane oxidation and reforming by H2O (SMR) and CO2 (DMR: dry methane reforming) to syngas is a promising reaction system for monetizing a power plant waste stream while reducing the emissions of two GHGs. Spatially resolved concentration and temperature measurements elucidate the coupled exothermic and endothermic reaction systems. Reactor concepts that utilize the heat generated by the oxidation to drive the endothermic reforming are described.

ABOUT THE SPEAKER

Mike Harold is the Cullen Engineering Professor in the William A. Brookshire Department of Chemical and Biomolecular Engineering at the University of Houston (UH). Harold received his BS in Chemical Engineering from Penn State and PhD in Chemical Engineering from the University of Houston.  In 1985 he joined the Chemical Engineering Dept.  at the University of Massachusetts where he became Associate Professor.  In 1993 Harold joined DuPont Company, where he held various technical and managerial positions. Harold joined UH as Chair of Chemical Engineering Dept. in 2000. He served in that role from 2000-08 and again from 2013-20. With expertise in catalysis and reaction engineering, Harold has served as advisor of 40 doctoral students, authored 200 peer-reviewed papers and book chapters, and presented 135 invited lectures.  His external honors include the American Institute of Chemical Engineers R.H. Wilhelm Award in 2023, Award for Excellence in Applied Catalysis from the Southwest Catalysis Society in 2019, and AIChE Fellow in 2014. He has also received a number of honors at UH, including the Ester Farfel Award (highest honor to faculty member) and the Senior Faculty Award for Research & Scholarship, both in 2013, and the Abraham E. Dukler Distinguished Faculty Award in 2009. Harold has been active in professional service roles and activities. He served as Editor-in-Chief of the AIChE Journal from 2012 through 2021, Chair of the AIChE Catalysis and Reaction Engineering Division in 1999 and 2022, and President of ISCRE Inc. in 2017-18.