Kinetic Modeling of Low Temperature Water-Gas Shift Reaction using gPROMS

Document Type: Original Article

Authors

1 Department of Chemical Engineering, Petroleum University of Technology, Abadan, Iran.

2 Department of Gas Engineering, Petroleum University of Technology, Ahwaz, Iran.

Abstract

The kinetics of water gas shift reaction was studied over commercial CuO/ZnO/Al2O3 in an integral fixed bed reactor. The experimental data were collected from literature. The CO conversion data in the temperature ranging from 180 ºC to 300 ºC were used for kinetic modeling. Surface redox and the Langmuir-Hinshelwood models as well as two empirical rate equation models, namely Moe and power law, were proposed to fit the experimental data. Using non-linear programming parameter estimation in gPROMS software, rate expressions were fitted to experimental data. The judgment among models was based on the statistical results. The surface redox mechanism was found to be the best model with apparent activation energy of 11.87 (kJ/mol). Also fitting of empirical models to experimental data showed that power law rate equation has a good fit in partial reaction order of 2.57, 2.02,   -0.59 and -3.4 for CO, H2O, CO2 and H2 respectively with activation energy of 39.48 (kJ/mol). Using surface redox kinetic model as well as power law kinetic rate equation, the reactor was simulated to validate the results by comparison of experimental and predicted CO outlet conversion rates. The simulation results validated the model predictions of power law and surface redox models.

Keywords