Design, Synthesis, and Mechanistic Evaluation of Iron-Based Catalysis for Synthesis Gas Conversion to Fuels and Chemicals
This project extends previously discovered Fe-based catalysts to hydrogen-poor synthesis gas streams derived from coal and biomass sources. These catalysts have shown unprecedented Fischer-Tropsch synthesis rate, selectivity for feedstocks consisting of synthesis gas derived from methane. During the first reporting period, we certified a microreactor, installed required analytical equipment, and reproduced synthetic protocols and catalytic results previously reported. During the second reporting period, we prepared several Fe-based compositions for Fischer-Tropsch synthesis and tested the effects of product recycle under both subcritical and supercritical conditions. During the third and fourth reporting periods, we improved the catalysts preparation method, which led to Fe-based FT catalysts with the highest FTS reaction rates and selectivities so far reported, a finding that allowed their operation at lower temperatures and pressures with high selectivity to desired products (C{sub 5+}, olefins). During this fifth reporting period, we have studied the effects of different promoters on catalytic performance, specifically how their sequence of addition dramatically influences the performance of these materials in the Fischer-Tropsch synthesis. The resulting procedures have been optimized to improve further upon the already unprecedented rates and C{sub 5+} selectivities of the Fe-based catalysts that we have developed as part of this project. During this fifth reporting period, we have also continued our studies of optimal activation procedures, involving reduction and carburization of oxide precursors during the early stages of contact with synthesis gas. We have completed the analysis of the evolution of oxide, carbide, and metal phases of the active iron components during initial contact with synthesis gas using advanced synchrotron techniques based on X-ray absorption spectroscopy. We have confirmed that the Cu or Ru compensates for inhibitory effects of Zn, a surface area promoter. The kinetic behavior of these materials, specifically the effects of H{sub 2}, CO, and CO{sub 2} on the rates and selectivities of Fischer-Tropsch synthesis reactions has led to a new proposal for the nature of rate-determining steps on Fe and Co Fischer-Tropsch catalysts, and more specifically to the roles of hydrogen-assisted and alkali-assisted dissociation of CO in determining rates and CO{sub 2} selectivities. Finally, we have started an exploratory study of the use of colloidal precipitation methods for the synthesis of small Fe and Co clusters using recently developed methods. During this period, we have had to restrict manpower assigned to this project because some irregularities in reporting and communications have led to the interruption of funding during this period. This has led to less than optimal productivity and to significant disruptions of the technical work. These issues have also led to significant underspending of project funds during this reporting period and to our consequent request for a no-cost extension of one year, which we understand has been granted.
- Research Organization:
- Univ. of California (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FC26-03NT41964
- OSTI ID:
- 882204
- Country of Publication:
- United States
- Language:
- English
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Design, Synthesis and Mechanistic Evaluation of Iron-Based Catalysis for Synthesis Gas Conversion to Fuels and Chemicals
Design, Synthesis, and Mechanistic Evaluation of Iron-Based Catalysis for Synthesis Gas Conversion to Fuels and Chemicals
Related Subjects
03 NATURAL GAS
09 BIOMASS FUELS
43 PARTICLE ACCELERATORS
ABSORPTION SPECTROSCOPY
ALKENES
BIOMASS
CARBURIZATION
CATALYSIS
CATALYSTS
DESIGN
EVALUATION
FISCHER-TROPSCH SYNTHESIS
IRON
METHANE
OXIDES
PROGRESS REPORT
REACTION KINETICS
SURFACE AREA
SYNCHROTRONS
SYNTHESIS
SYNTHESIS GAS