Kinetic study of the modified Fischer-Tropsch synthesis over an alumina-supported cobalt oxide catalyst

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5488120

Lu, D C

A modified Fischer-Tropsch reaction with the incorporation of ethylene in the synthesis gas has been studied kinetically. The feed mixture was also comprised of methane and carbon dioxide in a proportion similar to a real pyrolysis gas composition. An alumina-supported cobalt oxide catalyst was prepared by an impregnation method and used in the experimentation. A fixed-bed microreactor system was constructed and employed to carry out the experiments. The manipulated variables were the mass flow rates of hydrogen, carbon monoxide and ethylene, and the reaction temperature. Proper operating conditions for the kinetic experiments were as follows: (1) reaction temperature less than 498 K, (2) weight hourly space velocity greater than 41.4 gm/hr of feed per gram of catalyst, and (3) catalyst particle size smaller than 60 mesh. The liquid organic phase consisted mostly of straight chain alkanes (up to C/sub 35/). Some monomethyl paraffins and ..cap alpha..-olefins were also present in small amounts. The aqueous phase was comprised mainly of water and 1-propanol. Based on insignificant interparticle and intraparticle concentration gradients, a reaction mechanism was proposed with various alternative rate-determining steps. Corresponding intrinsic rate equations were derived to fit the experimental data, in terms of the rate, reaction temperature, and component partial pressures in the product, by the nonlinear Marquardt regression scheme. The study demonstrates that a model of the Eley-Rideal type, i.e., the reaction between the ethylene molecule and adsorbed hydrogen atom being the rate-determining step, may be the most probable course for the overall modified Fischer-Tropsch reaction to proceed.

• Research Organization: Arizona State Univ., Tempe (USA)
• OSTI ID: 5488120
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010403* -- Coal & Coal Products-- Hydrogenation-- (-1987)
ALKANES
ALKENES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMICAL REACTORS
COBALT COMPOUNDS
COBALT OXIDES
ELEMENTS
ETHYLENE
FISCHER-TROPSCH SYNTHESIS
HYDROCARBONS
HYDROGEN
KINETICS
MATHEMATICAL MODELS
METHANE
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
STRUCTURAL CHEMICAL ANALYSIS
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS