Non-catalytic and catalytic pyrolysis of citrus waste (orange peel)

ABSTRACT The development of industries requires energy sources. Therefore, the requirement for alternative renewal energy sources increases. They are solar, wind, wave, geothermal, and biomass. For the generation of energy from these sources, we apply thermochemical and biochemical methods. Amidst all the thermochemical origins, pyrolysis is advancing attention due to its ability to produce solid, liquid, and gaseous products. This article represents the non-catalytic and catalytic pyrolysis (573 -1173K) experiments conducted in a semi-batch reactor and TGA set up for citrus wastes (orange peel) collected from the local fruit juice seller outlet. The effect of catalysts observed and concluded that the presence of catalysts increases the yield of pyro-oil (30.79 wt.%→ 49.45 wt.%) with ZnO nanocatalyst to be the best performing catalyst. Reaction kinetics were also determined using isothermal and non-isothermal methods. The pH values of the pyro-oil investigated and observed that citrus waste pyro-oil is acidic, but the presence of catalyst makes it basic. The GC analysis of the pyro-gas infers that the gas contains CO and H2, which can be used as an energy source and feedstock for the Fischer–Tropsch process. Therefore, the utility of this type of pyrolyser is done in municipal areas of large cities. GRAPHICAL ABSTRACT