Numerical investigation of hydrogen production via methane steam reforming in a novel packed bed reactor integrated with diverging tube

Hydrogen is one of essential renewable energy sources to effectively solve the climate challenge and methane steam reforming accounts for 60.0% of global hydrogen supply. In this study, to improve the efficiency, the methane steam reforming in a packed bed reactor integrated with diverging tube was investigated via numerical method. To quantify the performance of flow and heat transfer, the flow disturbance analysis and the thermal resistance analysis of different inclination angle diverging tube were conducted. The results showed that, the integration of diverging tube lead to the reduction of average temperature, the decreasing of pressure drop and the increment of outlet mass flow. The flow disturbance and the thermal resistance increase with the inclination angle rising. As for the overall efficiency of flow and heat transfer, the improvement of flow has more effects than the weakness of heat transfer. As the inclination angle is 3 degrees, there is the highest overall heat transfer coefficient, which is increased by 9.0 % compared with the normal packed bed reactor. Since hydrogen production mainly depends on the flow and heat transfer, the integration of diverging tube improves the hydrogen yield and the hydrogen yield become larger with the inclination angle rising. Considering the usage of catalyst, the flow loss and outlet hydrogen mass flow, the efficiency of hydrogen production is the highest as the inclination angle is 3 degrees, which is increased by 34.0%.

Automated summary

In this study, methane steam reforming in a packed bed reactor integrated with a diverging tube was investigated numerically to improve efficiency. The results showed that the integration of a diverging tube led to a reduction in average temperature, a decrease in pressure drop, and an increase in outlet mass flow. Both flow disturbance and thermal resistance increased as the inclination angle rose. The overall heat transfer coefficient was highest at an inclination angle of 3 degrees, increasing by 9.0% compared to a normal packed bed reactor. The integration of a diverging tube improved hydrogen yield, which increased with the inclination angle. Considering catalyst usage, flow loss, and outlet hydrogen mass flow, the highest efficiency of hydrogen production was achieved at an inclination angle of 3 degrees, increasing by 34.0%.