Process modelling and optimization of hydrogen production from biogas by integrating DWSIM with response surface methodology

Abstract

Hydrogen production from biogas presents a significant opportunity to address major sustainability challenges by providing an economically viable replacement of fossil fuels and reducing greenhouse gas emissions. However, the conversion of biogas into hydrogen using steam reforming is affected by several process parameters. Therefore, this study aims to use a combined approach of DWSIM chemical process simulator and response surface methodology (RSM) as an optimization technique to enhance the effectiveness of the hydrogen production process. The process was modeled with the help of DWSIM software and then validated. Additionally, sensitivity analysis was performed to assess the impact of varying raw material flow rates and reactor conditions on the hydrogen yield as well as investigate the effect of varying biogas composition on the hydrogen yield. Design Expert software was used to optimize the hydrogen production using the Central composite design and a quadratic model. Four input parameters were considered: biogas flow rate, steam flow rate, inlet temperature, and pressure of reformer reactor, with hydrogen yield at the outlet of the last reactor considered as the response. The model and the independent parameters were found to be significant with p-values< 0.0001. The interactions of parameters showed that pressure had the least impact on the hydrogen yield. The optimal parameters identified were 57 kg/hr biogas flow rate, 33.97 kg/hr steam flow rate, 954.38 °C reformer inlet temperature, and 12.52 bar pressure, ultimately achieving a maximum hydrogen yield of 65.992 %. Validation of optimal conditions in DWSIM simulation tool yielded a hydrogen yield of 64.874 % with an error margin of <2.0 %. Overall, this study demonstrates the effect of each parameter and optimizes the hydrogen production process to increase the yield.