Simulation and enhancement of axial temperature distribution in a reactor filled with in-situ electrically heated structured catalyst

Abstract

The hydrogen production technology based on the in-situ electrically heated structured catalyst (EHSC) has the advantages of compact structure, fast response, and less CO2 emissions. However, there is still a lack of research on the temperature distribution of the reactor filled with EHSC. Based on the problem, a CFD model was established, and the temperature distribution was revealed. To further reduce the large temperature difference in axial direction, the effects of the gradient-pitch design and segmented-voltage-control design for the EHSC on the temperature distribution and methanol conversion were studied numerically. The results showed that segmented-voltage-control design can significantly reduce the maximum axial temperature difference, due to the fact that the reaction heat and corresponding Joule heat supplied at each axial section were flexibly well matched. When reaction temperature was 275 °C, the maximum temperature difference decreased from 84.7 °C to 31.1 °C. Moreover, when GHSV was 13000 ml/(g h), methanol conversion was improved by up to 10.9%. The segmented voltage control method for the EHSC provides an opportunity to design an isothermal endothermic reactor under any reaction conditions in the case of further optimization of segmented-voltage-control design.