Green hydrogen and electrical power production through the integration of CO2 capturing from biogas: Process optimization and dynamic control

Abstract

This study describes the optimization of a modelling process concerning biogas’ use to generate green hydrogen and electrical power. The Aspen Plus simulation tool is used to model the procedure, and the approach employed to limit the emissions of gas from the hydrogen production process will be the CO2 capture method. This technique uses slack lime (Ca(OH)2) to absorb CO2 capture since it is readily available. The study analyzes many critical parameters in the process, including the temperature and pressure in the steam reforming (SR) and the water gas shift (WGS) reactions along with the steam to carbon ratio (S/C) to determine how the production of green hydrogen and electrical power will be influenced. Electricity generation is achieved by taking the residual water from the SR, WGS, carbonation reactions and converting it to the vapour phase, allowing the steam to pass through the turbine to generate electricity. To examine the effects of the synchronized critical parameters, response surface methodology (RSM) was used, thus allowing the optimal operational conditions to be determined in the form of an optimized zone for operation. The result of parameter optimization gave the maximum green hydrogen production of 211.46 kmol/hr, and electric power production of 2,311.68 kWh, representing increases of 34.86% and 5.62%, respectively when using 100 kmol/hr of biogas. In addition, control structures were also built to control the reactors’ temperature in the dynamic section. The tuning parameters can control the SR and WGS system’s reactor to maintain the system in approximately 0.29 h and 0.32 h, respectively.