Comprehensive thermodynamic analysis, waste heat recovery strategies, and environmental impact assessment of advanced bio-oil steam reforming for sustainable green hydrogen production

This study presents a thermodynamic analysis of advanced steam reforming (ASR) of a bio-oil model compound, using conventional steam reforming (CSR) as a benchmark. ASR combines sorption-enhanced steam reforming (SESR) and chemical-looping steam reforming (CLSR) with CSR. Acetic acid serves as the model for bio-oil, as it is one of its major components. The steam reforming process is highly endothermic and requires substantial thermal energy. Additionally, the reformer product and waste gases from regeneration reactors also carry away significant heat energy. This energy can be recovered through a waste heat recovery system, reducing the energy demand for heating reactants and ultimately lowering the overall energy requirement. We conducted thermodynamic analyses over various operating parameters, including reformer temperature and steam-to-carbon molar ratios (SCMR), to identify optimal conditions for both CSR and ASR. The reformer temperature varied from 400 °C to 900 °C, while SCMR ranged from 1 to 4. Notably, the hydrogen mole fraction in SESR reached up to 99 % at a sorbent-to-carbon molar ratio (CaO/C MR), and the overall energy demand decreased by 28.45 % for CLSR at an oxygen carrier-to-carbon molar ratio (NiO/C MR) of 0.5. When incorporating a waste heat recovery system, the net energy demand decreased by 24.3 % for CSR and 33.15 % for ASR compared to scenarios without waste heat recovery. Furthermore, the potential environmental impact rates were significantly lower for ASR than for CSR, indicating that ASR is a more environmentally friendly process.