Status, developments, and sustainability of biowaste feedstock: A review of current progress

Modification of natural environments for the purpose of their utilisation has led to the degradation of more than 50 % of the world's original forests, highlighting the profound influence of human actions on global ecosystems. The world's cultivated land area has expanded by ∼13 % since 1961; however, with the world population doubling since then, we can only rely on half as much land as in 1961 for food production. The rapid exhaustion of natural resources, including land and water, emphasises the necessity for sustainable energy generation. Identifying sustainable energy sources such as biodiesel is critical, particularly when human land use has eradicated half of the planet's forests and agricultural lands are persistently diminishing due to population expansion. Waste cooking oil is a readily available, inexpensive, and widely distributed raw material for biodiesel production. Waste cooking oil is a potential source that can immediately solve the world's needs to generate more useable energy. This review article offers a thorough overview of biodiesel production using conventional methods, intensification processes, and various types of catalysts, along with their advantages and disadvantages. This review delves into optimisation of biodiesel production, including a thorough examination of process parameters such as the methanol/oil molar ratio, catalyst concentration, reaction temperature, reaction time, and stirring speed, and their effects on the biodiesel yield. The kinetics, thermodynamics, and energy consumption of the transesterification reaction, as well as exergy and energy analysis are covered. This article also presents the life cycle analysis and environmental impact assessment. On the whole, the production of biodiesel from waste cooking oil is a cleaner and economical alternative fuel for compression ignition engines.