Jeremy Palmer, assistant professor in the Cullen College’s chemical and biomolecular engineering department, was awarded the American Chemical Society Petroleum Research Fund’s Doctoral New Investigator Grant. The prestigious award supports fundamental, high-caliber research in the petroleum field and promotes the careers of young engineers and scientists.
Palmer will use the two-year, $110,000 award to design improved zeolite catalysts using computational modeling techniques.
Zeolites are three-dimensional, crystalline minerals used in a wide variety of industrial processes and commercial products. They occur naturally, but can also be mass produced synthetically. The petrochemical industry commonly uses zeolites as catalysts because they efficiently speed up chemical reactions and can be produced relatively cheaply.
“Zeolites help make many chemical reactions economically feasible on an industrial scale,” said Palmer.
Their topography, with thousands of tiny pores, makes them uber- effective as industrial catalysts. These tiny holes can temporarily trap individual molecules during a chemical reaction, thereby lowering the energy required to chemically-convert those molecules into more valuable compounds.
Compounds converted by zeolites are used in products ranging from fuels and plastics to value-added chemicals. Zeolites also help to make industrial processes more sustainable by minimizing the production of wasteful byproducts.
Palmer’s work is inspired by experiments done at the Cullen College by Jeffrey Rimer, Ernest J. and Barbara M. Henley Associate Professor of chemical and biomolecular engineering. In Rimer’s group, much has been discovered about the importance of the size and shape of zeolite crystals. Naturally-growing zeolites tend to form large crystals, but smaller crystals perform better as catalysts.
“Experimental work at UH has shown that smaller zeolite crystals last longer and give higher product yields. Both properties reduce waste and improve process sustainability,” said Palmer.
To control crystal size and shape, Rimer and his collaborators introduced growth modifiers – chemicals like amino acids and alcohols – into the growth solutions used to synthesize zeolites. When these compounds are present during crystallization, zeolite growth is systematically altered to produce a desired size and shape. The crystals can be tuned to form thin platelets, for example, when normally they would grow into the shape of large cylinders.
While experimental techniques have primarily been used to search for effective growth modifiers, Palmer’s work uses computer simulation to add predictive capability to the process.
“We want to identify classes of growth modifier compounds that are likely to work to get the desired crystal shape and size,” said Palmer. “This is slow and expensive to do experimentally, so we are harnessing the power of molecular modeling and the supercomputing facilities at UH’s Center for Advanced Computing & Data Systems to expedite the process.”
After identifying the growth modifier compounds that are most likely to cause the desired changes in crystal shape and size, Palmer will build computational models of zeolites to study how the chemical compounds interact with the surface of the zeolites. When the surface interactions are understood, Palmer know how the growth modifier compounds will alter the crystal’s shape and size.
It seems the smaller the zeolite, the larger the potential for impact on the oil and gas industry and the world around us. Looking to the future, small zeolites may help convert natural gas into products like polyethylene that have traditionally been derived from petroleum. Palmer said he hopes his team will help to realize that potential using his computer models.