Investigating the production of liquid fuels from synthesis gas (CO + H2) in a bench-scale packed-bed reactor based on Fe–Cu–La/SiO2 catalyst: experimental and CFD modeling

Mohammad Irani

doi:10.1007/s40090-014-0011-y

Abstract

A computational fluid dynamic (CFD) and experimental study of Fischer–Tropsch Synthesis (FTS) process in a fixed-bed reactor is presented. The reactor was a 1.2 cm diameter and 80 cm length steel tube in which ceramic particles were employed to dilute the catalyst bed and thus prevent the emergence of hot spot in it. An axi-symmetric CFD model with an optimized mesh of 22,016 square cells was developed to model hydrodynamics, chemical reaction, and heat and mass transfer in the reactor. Thermodynamic non-ideal behavior of the gas mixture was modeled using Peng–Robinson equation of state. Kinetic models for FTS and water–gas-shift reaction rates based on Langmuir–Hinshelwood type for each of the species were employed. Good agreement was achieved between the bench experimental data and the model. Performing reactions inside packed-bed reactor due to high pressure and temperature is very difficult and expensive, and CFD simulations are considered as numerical experiments in many cases. A sensitivity analysis was run to find the effect of temperature, pressure, GHSV and H2/CO ratio on the reactor performance. It was concluded that the obtained results from CFD analysis give precise guidelines for further studies on optimization of FTS fixed-bed reactor performance.

Highlights

Gas to liquid (GTL) process refers to the technologies designed to convert natural gas and coal into liquid
The Fischer– Tropsch technique consists of four major steps: (1) treatment of natural gas to remove water and impurities, (2) reforming of the natural gas to produce a mixture of carbon monoxide and hydrogen, called syngas, (3) Fischer–Tropsch synthesis (FTS) that produces heavier hydrocarbons from syngas and (4) upgrading to produce finished products
Some studies focused on the preparation, promotion and characterization of the catalysts [2,3,4,5,6] and kinetics of the FTS reactions [7,8,9], while some others worked on the effects of the operating conditions and combination of Fischer–Tropsch synthesis reactors on the performance of the reactor [10, 11]

Summary

Introduction

Gas to liquid (GTL) process refers to the technologies designed to convert natural gas and coal into liquid 11 Page 2 of 9Int J Ind Chem (2014) 5:11 hydrocarbons such as gasoline or diesel fuel. Gas to liquid (GTL) process refers to the technologies designed to convert natural gas and coal into liquid 11 Page 2 of 9. The Fischer– Tropsch technique consists of four major steps: (1) treatment of natural gas to remove water and impurities, (2) reforming of the natural gas to produce a mixture of carbon monoxide and hydrogen, called syngas, (3) Fischer–Tropsch synthesis (FTS) that produces heavier hydrocarbons from syngas and (4) upgrading to produce finished products. Some of the gas reservoirs are located in remote areas, and the transport of natural gas in these cases can be uneconomical. FTS can be used to convert natural gas into liquid fuels, and in this way the transport of energy source is much easier and economical [1]. Some studies focused on the preparation, promotion and characterization of the catalysts [2,3,4,5,6] and kinetics of the FTS reactions [7,8,9], while some others worked on the effects of the operating conditions and combination of Fischer–Tropsch synthesis reactors on the performance of the reactor [10, 11]

Methods

Results

Conclusion