Pyrolysis

Energy availability has always played a major role, directly or indirectly, for the growth, economical development, and social prosperity of any nation. The growing population, growing industrialization, rising crude oil prices, advancement in transportation, and so on have forced to find an alternative energy source, as fossil fuels are the only available source and are getting depleted at a faster rate. Although few renewable energy sources are available, they are intermittent, require high cost, are time dependent, and so on. The utilization of biomass has gathered the attention, as it is available in plenty and has required properties to generate bioenergy. Depending on the physicochemical properties of biomass, the direction for biomass treatment may be chosen. Both biological and thermochemical processes are available for bioenergy generation, but the low efficiency and more time requirement make biological process less preferable. The current thermochemical processes are pyrolysis, gasification, liquefaction, and combustion. Among them, pyrolysis is the most proficient way that involves the degradation of biomass to three (biooil, biochar, and pyrolytic gaseous) biofuels under inert atmosphere. The proportion of these products are dependent on various variables such as temperature, heating rate, bed height, reactor type, biomass properties, holding time, catalysts, and so on. The products obtained after pyrolysis can be further enriched using various technologies. Biooil is the main product for pyrolysis and is a complex mixture of oxygenated organic compounds. Biochar is a black solid carbonaceous multifunctional substance, and pyrolytic gases comprise gases such as CH4, CO, and H2, which have good combustion characteristics. Apart from these, the major challenges include the upgradation of products (mainly biooil) to its useable form. However, certain processes such as hydrotreating, hydrocracking, esterification, steam reforming, and so on are available for biooil upgradation. The products have the ability to become a substitute for the fossil fuel.