(317f) Catalytic Conversion of Biogas to Transportation Fuels and Chemicals

Efficient transformation of methane to more valuable chemical and fuel products continues to be an important intellectual challenge with strong economic rationale. A big driver is the abundance of methane both from fossil resources and renewable biological sources. Selective partial oxidation of methane and other alkanes can be performed effectively using bromine for C-H bond activation. The overall conversion occurs in a three-step process involving, i) bromination of methane, ii) catalytic reaction of alkyl bromide intermediates to form hydrocarbon products, and iii) recovery and recycle of bromine. The process does not utilize a synthesis gas intermediate and is tolerant to common methane contaminants including high concentrations of carbon dioxide present in biogas.

Activation of methane using bromine generates methyl bromide as the key intermediate. It is critical to develop catalysts for converting methyl bromide into higher hydrocarbons that can be used in gasoline and jet fuel. There is a remarkable similarity between methyl bromide and methanol in terms of reactivity and conversion to higher hydrocarbons over suitable catalysts. Conversion of methanol to olefins and also to gasoline was developed and commercialized by Mobil. A big advantage of the GRT technology is the ease and cost effectiveness of producing methyl bromide compared to methanol production. High-throughput catalyst screening was employed to identify catalyst leads to produce range of products including olefins, gasoline, and jet fuel components. Catalysts screened were based on ZSM-5, ferrierites, mordenites, MAPO, ALPO, SAPO and other zeolites. ZSM-5 based catalysts were the top performers in the production of aromatics and gasoline range components, while SAPO based catalysts were the top performers for olefins production. Novel methods for catalyst modification were used to improve product yields and reduce coke formation. Operating conditions such as temperature, pressure and residence time, have a big impact on the product distribution and coke formation.

This talk will provide an overview of the process to convert methane derived from biomass or fossil sources to chemicals and transportation fuels. The focus of the talk will be on catalyst screening for converting the methyl bromide intermediate into hydrocarbon products.

References:

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2. I. Lorkovic, M.L. Noy,W.A. Schenck, C. Belon, M.Weiss, S. Sun, J.H. Sherman, E.W. McFarland, G.D. Stucky, P.C. Ford, Catal. Today 98 (2004) 589.

3. A. Breed, M.F. Doherty, S. Gadewar, P. Grosso, I.M. Lorkovic, E.W. McFarland, M.J. Weiss, Catal. Today 106 (2005) 301.