Evaluation of thermodynamically favourable operating conditions for production of hydrogen in three different reforming technologies

With the aid of thermodynamic analysis using AspenPlus™, the characteristics of three different types of reforming process are investigated. These include: steam-methane reforming (SMR), partial oxidation (POX) and autothermal reforming (ATR). Thereby, favourable operating conditions are identified for each process. The optimum steam-to-carbon (S:C) ratio of the SMR reactor is found to be 1.9. The optimum air ratio of the POX reactor is 0.3 at a preheat temperature of 312 °C. The optimum air ratio and S:C ratio of the ATR reactor are 0.29 and 0.35, respectively at a preheat temperature of 400 °C. Simulated material and energy balances show that the CH4 flow rates required to generate 1 mol s−1 of hydrogen are 0.364 mol s−1 for POX, 0.367 mol s−1 for ATR and 0.385 mol s−1 for the SMR. These results demonstrate that the POX reforming system has the lowest energy cost to produce the same amount of hydrogen from CH4.