Proposing a novel theoretical optimized model for the combined dry and steam reforming of methane in the packed-bed reactors

摘要

A packed-bed reactor was modeled for combined dry and steam reforming (CDSR) and simulated using a two-dimensional heterogeneous model at steady-state condition. The model outputs showed a good agreement with experimental data. The effects of important operational parameters such as feed temperature, pressure, molar flow, and CO_2/ CH_4 and H_2O/ CH_4 ratios on methane conversion and H_2/ CO ratio in synthesis gas were also evaluated. Afterward, the modified artificial neural network (ANN) model was used for approximating the results of a simulation with high accuracy. The outputs of ANN model show that the predicted values of ANN model are in good agreement with those of the heterogeneous model, suggesting that the model was successfully developed to capture the correlation between operation conditions, methane conversion, and H_2/ CO ratio in the synthesis gas. Finally, a multi-objective optimization based on the hybrid of ANN and non-dominated sorting genetic algorithm-II (NSGA-II) was carried out to find the best-operating conditions for the methanol production and Fischer- Tropsch synthesis reaction with the desired H_2/ CO molar ratio of about two in synthesis gas. So, the main objectives for CDSR are providing a high methane conversion and also H_2/ CO ratio of two in the output synthesis gas.