MODELING AND SIMULATION OF FISHER-TROPSCH REACTOR

Abstract

Over the last few years a strong national interest has been sparked in alternative energy sources due to the rise in petroleum and natural gas prices and increasing dependence on foreign suppliers o f liquid fuels. Liquefaction technologies that can produce liquid fuels from coal have existed for more than 80 years. The most widely used coal liquefaction technology employs an indirect process in which the coal is gasified into a synthesis gas that is then converted into liquid fuels using the Fischer-Tropsch (F-T) process. Fischer—Tropsch synthesis (FTS) is the preferred route for the production of chemicals and liquid fuels from natural gas, coal, and biomass. It converts synthesis gas (CO + H2) into hydrocarbon chains. In this study, a water-cooled fixed bed Fischer-Tropsch reactor packed with Fe-HZSM5 catalyst has been modeled (Two dimension) using the intrinsic reaction rates previously developed at RIPI-NIOC (Research Institute of Petroleum Industry, National Iranian Oil Company). The FischerTropsch synthesis reactor was shell and tube type with high pressure boiling water circulating on the shell side.Model is simulated using Fluent 6.3 software package. Simulation results were validated against the pilot plant data obtained by RIPI-NIOC. The effects of some important parameters such as cooling temperature, reactor internal diameter and H2/CO molar ratio in feed on the performance capability of the reactor are investigated. Based on parametric sensitivity analysis optimum conditions were reached with cooling temperature =555K, reactor ID=3.8cm and H2/CO molar ratio=0.96.