Energy Self-Sufficiency Conditions of Ethanol Autothermal Reforming: a Simulation Study

Natural gas steam reforming is commonly used for hydrogen production. However, research has shown that ethanol autothermal reforming can produce cleaner hydrogen gas efficiently. Despite this, there is a lack of studies on the energy self-sufficiency conditions of the ethanol autothermal reform. In this paper, we use simulations and the Response Surface Methodology (RSM) for the multivariate analysis of the energy self-sufficiency conditions in this process. First, we constructed and validated an industrial flowchart. After that, RSM allowed us to assess the process variables effects. The process variables studied were temperature (0 to 1000 degrees C), pressure (20 to 30 bar), steam/ethanol ratio (2 to 5 mol/mol) and O-2/ethanol ratio (0 to 1.5 mol/mol). We observe that the temperature and steam/ethanol ratio increase have a positive effect on hydrogen production. On the contrary, the O-2/ethanol ratio increase has a negative effect, and the pressure increase is not statistically significant on hydrogen production. Therefore, the pressure was used at its minimum level (20 bar) while the temperature and the steam/ethanol ratio at its maximum levels (1000 degrees C and 5 mol/mol). We also evaluated the energy consumption for the Autothermal Reactor (ATR). The reactor consumed 477.92 kJ/mol ethanol to produce 5.12 mol H-2/mol ethanol when we use 1000 degrees C, 20 bar, steam/ethanol 5 mol/mol, and O-2/ethanol 0 mol/mol. ATR's energy self-sufficiency is achieved by using 1000 degrees C, 20 bar, steam/ethanol 5 mol/mol, and O-2/ethanol 0.86 mol/mol. In these conditions, 3.95 mol H-2/mol ethanol is produced with 0 kJ/mol ethanol.