Kinetic studies of Fischer-Tropsch synthesis on suspended iron/potassium catalyst - rate inhibition by carbon dioxide and water

Fischer–Tropsch Synthesis in Slurry Bubble Column Reactors: Experimental Investigations and Modeling – A Review

This paper presents an extensive review of the kinetics, hydrodynamics, mass transfer, heat transfer and mathematical as well as computational fluid dynamics (CFD) modeling of Low-Temperature Tropsch Synthesis (LTFT) synthesis in Slurry Bubble Column Reactors (SBCRs), with the aim of identifying potential research and development areas in this particular field. The kinetic expressions developed for F-T synthesis over iron and cobalt catalysts along with the water gas shift (WGS) reactions are summarized and compared. The experimental data and empirical correlations to predict the hydrodynamics (gas holdup, Sauter mean bubble diameter, and bubble rise velocity), mass transfer coefficients and heat transfer coefficients are presented. The effects of various operating variables, including pressure, temperature, gas velocity, catalyst concentration, reactor geometry, and reactor internals on the hydrodynamic and transport parameters as well as the performance of SBCRs are discussed. Additionally, modeling efforts of SBCRs, using axial dispersion models (ADM), multiple cell recirculation models (MCCM) and computational fluid dynamics (CFD), are addressed. This review revealed the following: (1)

Modeling and Simulation of a Fischer–Tropsch Slurry Bubble Column Reactor Using Different Kinetic Rate Expressions for Iron and Cobalt Catalysts

A user-friendly simulator based on a comprehensive computer model for slurry bubble column reactor (SBCR) was used to predict the performance of a conceptual commercial-scale (9-m ID and 50-m height) SBCR for Fischer–Tropsch (F–T) synthesis. Novel correlations for predicting the hydrodynamic and mass transfer parameters; a new relationship between the axial dispersion of large gas bubbles and their average diameter; and up to ten different kinetic rate expressions available in the literature for iron and cobalt-based catalysts were included in the simulator. The effects of operating conditions, including catalyst concentration, pressure, temperature, H2/CO ratio, and superficial gas velocity on the SBCR performance were predicted using the simulator for both types of catalysts. The predictions showed that the performance of the reactor was strongly dependent on the type of catalyst and the kinetic rate expression used.