Pyrolysis of Manilkara zapota seeds over ZSM-5 to produce high-quality bio-oil and chemicals.

• Manilkara zapota seed is a waste biological resource available in India. • This seed was pyrolyzed over ZSM-5 in a semi-batch reactor. • Yield of biochar decreased with increase in temperature from 400 to 600 °C. • Introduction of catalysts reduced oxygenated compounds and increased the hydrocarbons. • Catalyst also increased the energy content of pyrolytic oil. The present study addressed the thermal and catalytic pyrolysis of Manilkara zapota seeds (CK) using a semi-batch reactor to understand the effect of process parameters and ZSM-5 on the yield and properties of pyrolytic end products. The physicochemical results endorsed the inherent competence of CK for production of renewable fuels and allied chemicals. Pyrolysis was conducted at varying biomass to catalysts ratios (B/C) (3:1, 6:1, 8:1 and 10:1, respectively) at optimized process conditions. The pyrolysis results confirmed that thermal pyrolysis produced a higher yield of pyrolytic liquid (45.22 wt%) than catalytic pyrolysis (37.98 wt%) at 8:1 B/C ratio. However, the introduction of catalyst improved the properties of catalytic pyrolytic oil vis-à-vis thermal pyrolytic oil by dampening its oxygenated products and viscosity, while increasing the gross heating value (40.38 MJ kg−1). The FTIR study of thermal and catalytic pyrolytic oil confirmed the presence of water, acid, alkane, aromatic, and phenol while GC–MS results demonstrated the use of the catalyst at optimised conditions predominantly reduced the oxygenated products and acids while substantially increased the hydrocarbons. Furthermore, the characterisation of CK biochar confirmed its potential towards utilisation in various industrial and domestic applications. [ABSTRACT FROM AUTHOR]