Catalytic microwave preheated co-pyrolysis of lignocellulosic biomasses: A study on biofuel production and its characterization

[Display omitted] •Catalytic and non-catalytic co-pyrolysis processes are used for bio-oil production.•Microwave preheated co-pyrolysis yielded higher bio-oil at 0.25 mm particle size.•CaO aided co-pyrolysis of PP, GS and PCW showed bio-oil yield of 51.6%.•FE-SEM results confirmed the changes in morphological structure of biomasses with CaO.•NMR results of pyrolysis oil exposed the presence the hydroxyl radicals and ethers. In this present study, microwave pre-treatment has been used for sustainable biofuel production from three different biowastes through catalytic aided co-pyrolysis techniques. The experimental investigations have been carried out to develop biofuel at temperature (350-550℃), heating rate (15-50℃/min) and particle size (0.12–0.38 mm). The resultant biofuels were characterized using TGA, DTA, FE-SEM, FTIR spectroscopy and NMR spectrum. The pyrolysis process of biomasses without and with catalyst resulted in the yield rate of 29–37% and 39–51% respectively. Moreover, the CaO catalytic co-pyrolysis process of pomegranate peel, groundnut shell and palmcone wastes with a ratio of 50:50 at 0.25 mm particle size has resulted in the highest yield rate of 51.6%. The NMR result of bio-oil samples produced hydroxyl group and aliphatics which clearly state the suitability of bio-oils for automotive application. The bio-oil had promising fuel characteristics consisting more energy density (29.1 MJ/kg), less oxygen content and free of nitrogen.