Intrinsic kinetics of Fischer-Tropsch reactions over an industrial Co-Ru/γ-Al2O3 catalyst in slurry phase reactor

Abstract

The rate of Fischer-Tropsch synthesis over an industrial well-characterized Co-Ru/γ-Al2O3 catalyst was studied in a laboratory well mixed, continuous flow, slurry reactor under the conditions relevant to industrial operations as follows: temperature of 200-240 °C, pressure of 20-35 bar, H2/CO feed ratio of 1.0-2.5, gas hourly space velocity of 500-1500 N cm3 gcat- 1 h- 1 and conversions of 10-84% of carbon monoxide and 13-89% of hydrogen. The ranges of partial pressures of CO and H2 have been chosen as 5-15 and 10-25 bar respectively. Five kinetic models are considered: one empirical power law model and four variations of the Langmuir-Hinshelwood-Hougen-Watson representation. All models considered incorporate a strong inhibition due to CO adsorption. The data of this study are fitted fairly well by a simple LHHW form - RH2 + CO = apH20.988pCO0.508 / (1 + bpCO0.508)2 in comparison to fits of the same data by several other representative LHHW rate forms proposed in other works. The apparent activation energy was 94-103 kJ/mol. Kinetic parameters are determined using the genetic algorithm approach (GA), followed by the Levenberg-Marquardt (LM) method to make refined optimization, and are validated by means of statistical analysis. Also, the performance of the catalyst for Fischer-Tropsch synthesis and the hydrocarbon product distributions were investigated under different reaction conditions. © 2009 Elsevier B.V. All rights reserved.