A comprehensive thermodynamic analysis of hydrogen and synthesis gas production from steam reforming of propionic acid: Effect of O₂ addition and CaO as CO₂ sorbent

A thermodynamic analysis was performed for the production of synthesis gas and hydrogen gas from steam reforming of propionic acid, one of the constituents of the bio-oil, using ASPEN Plus v8.8. The aim of the study was to perform a global analysis on steam reforming of propionic acid focusing on several parameters such as steam-to-propionic acid ratio, reaction temperature, addition of O₂ in the feed stream and presence of CaO as a CO₂ sorbent in the reaction environment. The results showed that higher amounts of steam/propionic acid ratio resulted in higher H₂ and CO₂ yields. It was also observed that high H₂O/PA molar ratios led to reduced coke production as WGS reaction was favored with excess steam, causing CO in the reaction mixture to be consumed through the WGS reaction rather than the Boudouard reaction. Addition of O₂ in the reaction environment was observed to negatively affect yield of H_2. Yet, coke formation was deprived and increasing the O₂ amount in the feed stream decreased the energy required for the process. Furthermore, the presence of CaO enhanced H₂ yield and energy requirements of the process compared to conventional steam reforming process. 100 % yield of H₂ production with a heat generation of −83.4 MJ/kmol of PA and almost zero formation of CO₂, CO, CH₄ and coke is achieved at 600 °C for sorption enhanced steam reforming of propionic acid.