A Review on Pyrolysis of Agro-waste and Plastic Waste into Biofuels: Shifting to Bio-based Economy

An increase in world energy consumption and its subsequent effect of carbon emission necessitates a shift towards the use of clean and sustainable fuels. Biomass is a promising resource for energy generation owing to its renewable nature and substantial energy content. The addition of plastics to improve the product yield has also been elaborated. Thermogravimetric analysis is a technical tool that can be used to elucidate the pyrolysis temperature and heating rate. Activation energy helps to identify the energy requirement for the pyrolysis process. Kinetics of the pyrolysis process is an effective tool for determining the minimum energy requirement and feasibility. This review highlights the importance of reaction kinetics, exergy, and energy analysis. The liquid fuel obtained through the thermal cracking of biomass has the potential to be used as a blend with conventional petroleum fuels. Substitution/blending of pyro-oil with petroleum fuels helps to reduce greenhouse emissions and global warming. The oxygen content of rice straw and Alga Sargassum sp. is 55 and 67%, respectively. Energy and exergy analysis improves the process economy. The success of any technology depends on its easy handling and economic feasibility. This review is the first of a kind in throwing light on the energy and exergy analysis of the pyrolysis process. Pyro-oil has an increased amount of oxygen content which has to be upgraded for further use. Pyrolysis also serves as an efficient tool for converting plastic waste into energy.

Graphical Abstract