Comparative study of in-situ catalytic pyrolysis of rice husk for syngas production: Kinetics modelling and product gas analysis

Pyrolysis of rice husk (RH) in the presence of three different types of catalysts (nickel, natural zeolite, and coal bottom ash) for syngas production were investigated by TGA-MS. The catalyst to RH ratio of 0.1 was pyrolyzed at different heating rates of 10, 20, 30, and 50 Kmin-1 in the temperature range of 323 K–1173 K. Furthermore, X-ray diffraction (XRD), Brunaur-Emmett-Teller (BET), field emission scanning electron microscope (FESEM) and X-ray fluorescence (XRF) were employed to understand the physiochemical properties and activities of the catalysts before and after pyrolysis of RH. Lastly, four different types of kinetic models such as first-order Coats-Redfern equation, Friedman, Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) were employed to determine the activation energy (EA). The kinetic analysis revealed that the EA values reduced when catalysts were introduced into RH as compared to absence of catalysts in the pyrolysis process. The lowest EA value was attained in catalytic pyrolysis using natural zeolite (51.35–157.4 kJ/mol), followed by coal bottom ash (53.56–161.4 kJ/mol) and nickel (56.51–162.9 kJ/mol).