Kinetic modeling of Fischer–Tropsch synthesis over [formula omitted] catalyst in slurry phase reactor

Abstract

Comprehensive kinetics of slurry phase Fischer–Tropsch synthesis (FTS) on an industrial Fe – Cu – K – SiO 2 catalyst, in the presence of water–gas shift (WGS), is studied using a stirred tank slurry reactor. A series of rival models for FTS and WGS reaction are derived using Langmuir–Hinshelwood–Hougen–Watson (LHHW) approach. In order to describe the deviation from ideal hydrocarbon distribution, secondary reactions of primary olefin on a separated active site and its chain length dependent solubility in slurry phase are taken into account. It is found that the optimal model is based on the mechanism that the rates of FTS are determined by insertion of methylene ( CH 2 ) via the alkylidene propagation mechanism and the rate of WGS reaction is controlled by the desorption of CO 2 via formate intermediate mechanism. Present model can describe the CO conversions and hydrocarbon distributions consistently and accurately over large interval of reaction conditions ( 523 – 563 K , 1.0 – 2.5 MPa , H 2 / CO ratio: 0.67 – 1.5 , and space velocity: 1000 – 2500 ml g cat - 1 h - 1 ) . On the other hand, the success predictions of the deviation from ideal distribution suggest the strong influence on the secondary reactions by the chain length dependent solubility of olefins.