Density functional theory evaluation of rare-earth oxides for biomass gasification effluent cleanup

Matthew D. Krcha, Adam D. Mayernick, Michael J. Janik, Kerry M. Dooley

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Biomass conversion to liquid fuels may be accomplished through gasification to syngas followed by fuel synthesis processes, enabling a renewable energy source of liquid fuels. Prior to fuel synthesis catalysts, the syngas must be cleaned of sulfur and tar species. In a Department of Energy forecast for 2012, approximately 50% of the cost to produce ethanol from biomass is involved in syngas cleanup. Mixed Rare-Earth Oxides (REOs) have shown promise in both desulfurization and hydrocarbon conversion. Our goal is to design a REO catalyst that can reform the large hydrocarbons into CO and H 2 and remove sulfur at high temperatures, thus making biomass gasification-based processes viable for sustainable liquid fuel production. Density functional theory (DFT+U) is used to generate composition-function relationships of mixed REOs for H 2S adsorption and hydrocarbon conversion. Oxygen vacancy sites in the doped oxide serve as the active site for H 2S adsorption and dissociation. Relative rates of the initial H 2S activation step predict trends in experimental H 2S adsorption capacity over a series of dopants in ceria, suggesting surface kinetic rates impact the adsorption capacity. As an indicator of methane reforming and tar cracking activity, the C-H bond activation energy of ceria based catalysts doped with transition metals is correlated with the surface reducibility. The findings from the DFT calculations compare with experimental H 2S adsorption energy and propane reforming activity.

Original languageEnglish (US)
Title of host publication11AIChE - 2011 AIChE Annual Meeting, Conference Proceedings
StatePublished - Dec 1 2011
Event2011 AIChE Annual Meeting, 11AIChE - Minneapolis, MN, United States
Duration: Oct 16 2011Oct 21 2011

Publication series

Name11AIChE - 2011 AIChE Annual Meeting, Conference Proceedings

Other

Other2011 AIChE Annual Meeting, 11AIChE
CountryUnited States
CityMinneapolis, MN
Period10/16/1110/21/11

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)

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