Role of Additives in Enhancing the Performance Characteristics and Stability of Biodiesel—A Review

摘要

Biodiesel is arenewable, nontoxic environment-friendly fuel produced by biological processes, derived directly or indirectly from plants, animals, agricultural, domestic, or industrial wastes. It has lower carbon emissions and higher cetane number. Although biodiesel is a clean renewable source of energy, due to its chemical instability, there are a few drawbacks related to its performance and storage like poor heat generation capacity, poor efficiency, high viscosity, high cloud point and pour point, high NO_x emissions due to excess nitrogen and oxygen, gel formation at low temperatures due to poor cold flow properties, etc. To optimize the quality of biodiesel and to increase stability, additives are added to the blend to improve the performance characteristics of biodiesel and to control emissions. The objectives of this review paper are to provide an insight into the need of additives to enhance the performance characteristics like brake thermal efficiency and brake specific fuel consumption of biodiesel, present a literature review of the use of additives on biodiesel, compare the results and investigate the impact of additives on performance parameters and stability. Pyrogallol, diethyl ether, butylhydroxyanisole (BHA), butylhydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) are the predominant additives under this review. It is clear from research that additives have a significant impact on the performance of biodiesel and there is scope for further research into additives to optimize the performance of biodiesel.