Auto-Thermal Chemical Looping Reforming Process in a Network of Catalytic Packed-Bed Reactors for Large-Scale Syngas Production: A Comprehensive Dynamic Modeling and Multi-Objective Optimization

The necessity of alleviating the environmental challenges associated with the steam-methane reforming (SMR) process has paved the way towards the utilization of clean alternative processes for the production of syngas and hydrogen. In this regard, auto-thermal chemical looping reforming (a-CLR) of methane has emerged as one of the most promising and energy-efficient alternatives. The current research is devoted to the feasibility study of an a-CLR process performed in a network of large-scale packed-bed reactors via a dynamic mathematical model. Here it is demonstrated that the large furnace of the conventional SMR process could be eliminated in the proposed a-CLR system at the expense of a 0.22 abatement in the yield of syngas. Further, based on the proposed cyclic design of the a-CLR process, for the continuous production of syngas a network of packed-bed reactors with seven and five furnace-free reactors in parallel are required for the high-capacity case, i.e. 184 tubes, and the low-capacity case, i.e. 115 tubes, respectively. The auto-thermal operation is not achievable completely in the high-capacity a-CLR case. However, by decreasing the total capacity by 38%, it is conceivable to fully cover the total heat demand in the low-capacity a-CLR case. Utilizing the optimum values of the inlet temperature and steam to carbon ratio as well as the initial oxidation degree in the optimized a-CLR case leads to a 17% enhancement in the methane conversion and also a 0.64 rise in the syngas yield in comparison with the non-optimized a-CLR case. [GRAPHICS] .

Automated summary

This study investigates the feasibility of an auto-thermal chemical looping reforming (a-CLR) process in a network of large-scale packed-bed reactors using a dynamic mathematical model. The results show that the proposed a-CLR system can replace the large furnace in the conventional SMR process with a slight decrease in syngas yield. By optimizing the operation conditions, methane conversion and syngas yield can be significantly improved.