Energy and Exergy Analysis of Green Hydrogen Production

Biomass pyrolysis and gasification are recognized as effective thermal technologies for producing green hydrogen obtained through thermal conversion from biomass. This research paper presents a comparatmive analysis of the energy and exergy performance of pyrolysis and gasification systems. The study investigates two critical process conditions: low-temperature pyrolysis at 500°C and high-temperature gasification at 900°C. The analysis integrates thermodynamic equilibrium calculations and modeling to produce hydrogen and offers a comprehensive evaluation of energy and exergy efficiencies. The comparison is carried out between a downdraft gasifier and a pyrolysis process, both employing wood chips as the biomass feedstock. This paper delves into the energy and exergy yields of these distinct thermal conversion methods for energy production. The research identifies pyrolysis at 900°C as the optimal model condition due to its lower energy consumption and the absence of agent materials. Energy and exergy analyses are conducted at both 500°C and 900°C for all processes. The model results demonstrate that pyrolysis yields 60% energy at 500°C and 94% at 900°C. Furthermore, the study reports on the effects of temperature variations on energy and exergy yields. This study contributes to the examination of the performance of thermal conversion methods from biomass for green hydrogen production.