Optimization of two bio-oil steam reforming processes for hydrogen production based on thermodynamic analysis

摘要

Thermodynamics of hydrogen production from conventional steam reforming (C-SR) and sorption-enhanced steam reforming (SE-SR) of bio-oil was performed under different conditions including reforming temperature, S/C ratio (the mole ratio of steam to carbon in the bio-oil), operating pressure and CaO/C ratio (the mole ratio of CaO to carbon in the bio-oil). Increasing temperature and S/C ratio, and decreasing the operating pressure were favorable to improve the hydrogen yield. Compared to C-SR, SE-SR had the significant advantage of higher hydrogen yield at lower desirable temperature, and showed a significant suppression for carbon formation. However excess CaO (CaO/C 1) almost had no additional contribution to hydrogen production. Aimed to achieve the maximum utilization of bio-oil with as little energy consumption as possible, the influences of temperature and S/C ratio on the reforming performance (energy requirements and bio-oil consumption per unit volume of hydrogen produced, Q(D/H2) (kJ/Nm(3)) and YBio-oil/H2 (kg/Nm(3))) were comprehensively evaluated using matrix analysis while ensuring the highest hydrogen yield as possible. The optimal operating parameters were confirmed at 650 degrees C, S/C = 2 for CSR; and 550 degrees C, S/C = 2 for SE-SR. Under their respective optimal conditions, the YBio-oil/H2 of SE-SR is significant decreased, by 18.50% compared to that of C-SR, although the Q(D/H2) was slightly increased, just by 7.55%. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.