Hydrogen Production via Catalytic Steam Reforming of Bio-oil Derived from Agricultural Residue

Abstract

Continued industrialization and urbanization all around the globe have resulted in equally rapid growth in global energy consumption as well as demand. This massive surge in energy demands has increased our dependence on fossil fuels to the point, where it is resulting in unwarranted consequences. Catalytic steam reforming (SR) of agricultural waste derived bio-oil for hydrogen production is a unique technology, offering twin benefits of waste management as well as sustainable energy production. The present study aims at developing a stable catalytic system for bio-oil steam reforming process to produce green hydrogen. The bio-oil used in this study was produced in the lab through pyrolysis of blend of agricultural residues. The produced bio-oil was characterized via gas chromatography mass spectrometry (GCMS) and Fourier transform infrared spectroscopy (FTIR). Furthermore, the perovskite catalysts LaNixM1-xO3 (M = Co, Cu, and Fe) used for steam reforming process, were synthesized using sol-gel method and their catalytic performance towards hydrogen production and bio-oil conversion was evaluated in a fixed bed tubular reactor. A wide array of techniques such as X-ray diffraction (XRD), Brunauer-Emmett-Teller surface area (BET), NH3 and CO2 -TPD (temperature programmed desorption), field emission scanning electron microscopy (FE SEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and pyridine-FTIR were used to analyze the material properties of the synthesized catalysts. The results of these analyses verified the successful formation of the highly sought-after perovskite structure with good amount of surface oxygen vacancies as well as medium strength acidic and basic sites. To establish an efficient catalytic system, process parameter (space-time and reaction temperature) optimization and time on stream (TOS) studies were also conducted. The TOS results displayed that LaNi0.5Co0.5O3 perovskite catalyst is stable up to 12 h at 700 ºC for space-time of 17.4 kgcat.h/kgmolbio-oil. Additionally, the kinetic study of phenol steam reforming process were also performed to study the various kinetic parameters. In-depth characterizations (FE-SEM, TGA, Raman spectroscopy and XRD) of spent catalyst after the reaction not only gave further insights about the excellent activity exhibited by the chosen catalyst but also revealed information about the nature of the coke deposited on the surface. Furthermore, thermodynamic potential of various advanced steam reforming processes was evaluated and compared with the conventional steam reforming process.