CAREER: Selectivity Control in Methanol-to-Hydrocarbons Catalysis by Manipulating the Hydrocarbon Pool

University Of Minnesota-Twin Cities, Minneapolis MN

Investigators

Abstract

Energy is clearly a global grand challenge problem for the 21st century. Transportation fuels are a significant component, as there are no viable, world class scale alternatives to carbon-based fuels. To meet the constantly increasing demands while moving from petroleum, it will be essential to maximize carbon and energy efficiency for conversion of carbon sources such as coal, biomass, and natural gas into these products. In the so-called C1 route for this conversion, the carbon sources are reacted with steam and/or oxygen to produce synthesis gas (CO + H2), which can then be reacted to a broad slate of products. Methanol is one of these products which leads to hydrocarbon fuels. A 2009 report by the US National Academies titled Liquid Transportation Fuels from Coal and Biomass envisions methanol-to-hydrocarbons (MTH) as a large-scale commercial process that could impact the transportation fuel sector in the future. The underlying challenge in MTH chemistry is to do a selective job of producing only the hydrocarbon products desired. Mobil has commercialized MTG (methanol-to-gasoline) decades ago, and since then, only minor selectivity modifications have been achieved through modifying the parameters of the zeolite catalyst used. How to achieve better carbon efficiency and selectivity control remains the question. Prof. Aditya Bhan of the Department of Chemical Engineering at the University of Minnesota, Twin Cities proposes that better control will result when we manipulate both the catalyst and co-catalyst for these reactions. Mechanistic studies have shown that the reactions of methanol proceed through a hydrocarbon pool. The hypothesis is that the zeolite pores are nanoreactors in which the acid site and the hydrocarbon pool function as co-catalysts. Preliminary data have demonstrated that changing the nature of the hydrocarbon pool with other organic molecules as additives does significantly change the products coming out of the reactor. Bhan proposes an experimental program which will ultimately allow him to systematically tune selectivity in MTH by the addition of various additives which are combined with the appropriate zeolite catalysts resulting in making higher octane gasoline range hydrocarbons, or alternatively, light polymer grade olefins, more effectively from C1 precursors. The broader impact is the development of highly selective and atom efficient MTH catalyst systems will lead to new thermochemical processes for the processing of non-petroleum resources to meet the demand for high-energy density and fungible fuels to address the transportation fuel challenge. This proposed program allows Bhan to integrate research on chemical catalysis with education and outreach components which highlight the importance of chemical engineering in the area of energy conversion. Education will be enhanced by recruiting and mentoring undergraduate students from under-represented communities in energy research activities, and by an outreach program for curriculum development with K-12 schools in the Minneapolis/St. Paul area. This award is jointly made by the Catalysis and Biocatalysis Program of the Chemical, Bioengineering, Environmental, and Transport Systems Division and the Chemical Catalysis Program of the Division of Chemistry.