Design and optimization of a computer simulation model for green hydrogen production by waste heat recovery from Afyon biogas plant

Abstract

In this study, a thermodynamic model was designed with the Aspen Plus program and optimized multidimensionally of the Afyon biogas power plant to reduce the unit electricity cost and produce green hydrogen. The model also includes ORC integration to use the exhaust gas energy of the existing power plant. In the model, which includes the whole process from biomass receiving to final electricity production, the plant produces 4000 kW of net electrical power. As a result of ORC integration and optimization, the net electricity production of the plant and ORC were determined as 4625.42 kW and 1215.31 kW, respectively. These values correspond to 0.039 $/kWh unit electricity cost. The power obtained in ORC is stored by producing hydrogen during periods of low electricity demand. For this purpose, ORC power is primarily used to electrolyze H2S (green hydrogen) released in biogas production. The rest of the power is used in the electrolysis of water. Hydrogen, released in biogas production, is added to the storage process. As a result, approximately 7.447 kg/min of hydrogen is produced at the power plant, costing 0.18 $/kg.