Process Modeling of Hydrogen Energy Production from Biomass Through Steam Reforming Method and Optimization Using Response Surface Methodology

Renewable energy refers to clean energy generated from natural sources which constantly replenished. Biomass is a source of renewable energy that can produce several types of products, such as biodiesel, biofuel, and green diesel. Crude glycerol production was significantly rising in the past decade due to the increase in biodiesel production. Hydrogen energy can be produced from biogas as a renewable resource using a multistep process, including mainly the steam reforming method. In this study, glycerol was chosen as feedstock that is collected from biodiesel's side-production. Glycerol steam reforming (GSR) was a superior method in hydrogen production because of the high amount of hydrogen that can be produced as compared with other methods such as methane reforming. Process simulation of steam reforming of glycerol was carried out in Aspen Plus^® using different reactor types such as REquil, RGibbs, RPlug, and RCSTR. The results show that the RPlug model resulted in high glycerol conversion and high hydrogen production as compared with the other reactor types. The optimization of the RPlug model is carried out using response surface methodology (RSM) with a central composite curve design (CCD). The optimization result shows a good agreement of the predicted and actual values with an accuracy of about 95%. The optimum operating conditions were 717°C at 1.1 bar, the ratio of water flowrate of about 630 kmol/hr, and the length and diameter of RPlug are found to be 12 m and 3 m, respectively, as well as the number of tubes is 28 tubes.