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

With the aid of thermodn. anal. using AspenPlus, the characteristics of three different types of reforming process are investigated. These include: steam-methane reforming (SMR), partial oxidn. (POX) and autothermal reforming (ATR). Thereby, favorable operating conditions are identified for each process. The optimum steam-to-carbon (S:C) ratio of the SMR reactor is 1.9. The optimum air ratio of the POX reactor is 0.3 at a preheat temp. of 312 Deg. The optimum air ratio and S:C ratio of the ATR reactor are 0.29 and 0.35, resp. at a preheat temp. of 400 Deg. Simulated material and energy balances show that the CH4 flow rates required to generate 1 mol/s of hydrogen are 0.364 mol/s for POX, 0.367 mol/s for ATR and 0.385 mol/s for the SMR. These results demonstrate that the POX reforming system has the lowest energy cost to produce the same amt. of hydrogen from CH4.