Comparison of Axial and Radial Water Gas Shift Reactors Based on CFD Simulation

The water gas shift reaction is an important step in chemical engineering processes. The basic performances of an axial reactor and radial reactor are simulated using computational fluid dynamics (CFD)simulation. Two-dimensional models are constructed for the two types of reactors. Their performances are compared, and the influences of flow rate and steam/CO ratio on their performance are studied. The results show that the pressure and temperature profile of an axial reactor changes linearly along the flow direction, while it is unevenly distributed in a radial reactor. An increase in the flow rate leads to a slight decrease in the conversion rate and an increase in the pressure drop, especially for the axial reactor. The radial reactor can reduce the pressure drop significantly, but at the same time, there is a slight decrease in its conversion rate. This allows for an enlarged commercial reactor design. However, some measures should be taken such as to make the flow perpendicular to the radial direction uniform.