Isotopic tracer studies of Fischer-Tropsch Synthesis over Ru/TiO₂ catalysts

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

DOI:https://doi.org/10.2172/10159366· OSTI ID:10159366

Krishna, Kamala Raghunathan ^[1]

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1. Univ. of California, Berkeley, CA (United States)

Fischer-Tropsch synthesis is a process in which CO and H₂ react to give predominantly liquid hydrocarbons. The reaction can be considered a special type of polymerization in which the monomer is produced in situ, and chain growth occurs by a sequence of independently repeated additions of the monomer to the growing chain. A investigation has been conducted to study the CO hydrogenation reaction in order to better understand catalyst deactivation and the elementary surface processes involved in chain growth. Isotopic tracers are used in conjunction with transient-response techniques in this study of Fischer-Tropsch synthesis over Ru/TiO₂ catalysts. Experiments are conducted at a total pressure of 1 atmosphere, reaction temperatures of 453--498 K and D₂/CO (or H₂/CO) ratios of 2--5. Synthesis products are analyzed by gas chromatography or isotope-ratio gas chromatography-mass spectrometry. Rate constants for chain initiation, propagation and termination are evaluated under steady-state reaction conditions by using transients in isotopic composition. The activation energy for chain termination is much higher than that for propagation, accounting for the observed decrease in the chain growth parameter are also estimated. Coverages by reaction intermediates are also estimated. When small amounts of ¹²C-labelled ethylene are added to ¹³CO/H₂ synthesis gas, ethylene acts as the sole chain initiator. Ethylene-derived carbon also accounts for 45% of the C₁ monomer pool. 102 refs., 29 figs., 11 tabs.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 10159366
• Report Number(s): LBL--31822; ON: DE92017085
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010405
010408
C1 PROCESSES
CARBON MONOXIDE
CATALYSTS
CHEMICAL REACTION KINETICS
COMPUTER CODES
DIFFERENTIAL EQUATIONS
FISCHER-TROPSCH SYNTHESIS
GAS CHROMATOGRAPHY
HYDROCARBONS
HYDROGEN
HYDROGENATION AND LIQUEFACTION
MASS SPECTROSCOPY
RUTHENIUM
TITANIUM OXIDES
TRACER TECHNIQUES