Equilibrium Of Water-gas Shift Reaction Research Articles

A new concept for control and orientation of the distribution of clean hydrocarbons produced by Fischer–Tropsch synthesis over an industrial iron catalyst

In this work, the performance of the Fischer–Tropsch reaction over iron catalyst in three reactor configurations was theoretically studied and analyzed. Indeed, the control and the guidance of produced hydrocarbons composition were done using a new concept of membrane separation reactor. Our findings show that the composition can be imposed by the nature of the integrated membrane. Depending on the used membrane, the water gas shift reaction equilibrium can be shifted towards hydrogen production or towards carbon monoxide production and consequently, the H2/CO ratio was changed in situ for giving olefins or paraffin according to our requirements specification. Finally, it was found that using a water permselective membrane can boost the composition to C3–C5 olefin compounds, whereas the separation of carbon dioxide can enhance the formation of paraffins.

Thermodynamic equilibrium analysis of water-gas shift reaction using syngases-effect of CO2 and H2S contents

Abstract Thermodynamic equilibrium of water-gas shift reaction (WGSR) under various temperatures, pressures and steam-to-CO (S/C) ratios was analyzed by Gibbs free energy minimization method. Coal-derived syngases with various CO2 and H2S contents were used as the feedstock. Based on the obtained results, it was found that CH4 and carbon formations were enhanced when syngas CO2 content increases. Carbon-free WGSR can be resulted using high S/C ratio. However, CH4-free WGSR cannot be resulted even with low S/C ratios. From the H2O conversion and H2 yield variations, the temperature at which reverse WGSR occurs can be identified and found to decrease with the increase in S/C ratio. Solid CaO sorbent was employed for both CO2 and H2S removals in WGSR when sour syngas was used as the feedstock. It was found that WGSR performance was enhanced due to the CO2 and H2S removals by CaO. The H2S concentration can be decreased with decreased S/C ratio while increasing the reaction pressure was not favourable for H2 production and H2S removal in WGSR with CaO. Because WGSR performance enhancement due to CO2 and H2S removals occurred at high temperature, catalysts can be eliminated in sorption-enhanced WGSR.

Optimization of IGCC gasification unit based on the novel simplified equilibrium model

The increasing pollutant emissions due to the development of science and technology creates tough challenges for the whole world. As one of the main causes, the utilization of solid fuels, like coal and biomass, has attracted the attentions of researchers. To alleviate this pollution, gasification technology is widely promoted in many fields of modern industry, especially in its application for Integrated Gasification Combined Cycle (IGCC) plant. Improving the simulation of gasifier is one of the most effective and essential ways to mature gasification technology. In this paper, a novel simplified equilibrium model is proposed for IGCC gasification unit. Through the analysis of gasification mechanism, Water Gas Shift Reaction (WGSR) is verified as the control step to determine the compositions of syngas. The simplified model based on the equilibrium of WGSR is proposed, developed and validated with experimental data. Furthermore, the sensitivity analysis is completed to demonstrate the influences of key factors on syngas compositions, such as reaction temperature, oxygen feed ratio and water feed ratio. Finally, the IGCC gasification unit operation conditions are optimized and the Cold Gas Efficiency is improved approximately 10% after optimization.