International Journal of Energy Research, Vol.45, No.5, 6943-6957, 2021
Thermodynamic analysis of autothermal steam-reforming of methane for ammonia production
Autothermal reforming of methane is one of the most widely reported techniques for syngas production. This thermodynamic analysis discusses two aspects of autothermal reforming: first, to obtain hydrogen to nitrogen in the ratio 3:1, which is the most suitable feed ratio for ammonia production in the Haber-Bosch process, and then to find out the thermoneutral point of the process. Throughout the study, all simulations are carried out at 1 bar pressure and within the temperature range 500-1000 degrees C. Conditions with more than 99% methane conversion and 0.1% coke deposition are considered. Other parameters taken into account for optimization are OMR (oxygen to methane ratio) in range 0.4-0.6, SMR (steam to methane ratio) in range 1.5-3.5 and oxygen enrichment in air from 25% to 40%. This study briefly discusses the water gas shift (WGS) reaction for CO removal and its conversion to H-2. The best thermoneutral point for the reformer was found to be at OMR = 0.59845, SMR = 2.105, with an oxygen enrichment level of 39.4%.
Keywords:ammonia production;autothermal reforming;thermoneutral point;water gas shift reaction;hydrogen production