A Comprehensive Review on Rare Biodiesel Feedstock Availability, Fatty Acid Composition, Physical Properties, Production, Engine Performance and Emission

The world is now experiencing the first real global energy crisis, the effects of which will be felt for many years to come. Fossil fuels have accounted for more than 80% of the world’s energy requirements for decades. The cost of coal has reached record highs, while the price of oil reached at it’s peak in the middle of 2022 at well over 100 US dollars per barrel before declining. Rising energy costs of fossil fuels are driving a significant wealth shift from consumers to producers. The primary causes of the growing level of carbon dioxide in the atmosphere are fossil fuels. Stated Policy Scenario predicts a 1% annual growth in primary energy demand through 2030, which will be mostly satisfied by greater usage of renewable energy sources. Biodiesel is gaining popularity as a means of supplying energy since it is a renewable fuel, non-toxic, biodegradable, and locally available using recycled or agricultural materials with a lesser environmental effect. Biodiesel refers to a non-petroleum-based diesel fuel consisting of short-chain esters, made by using numerous resources, which can be used (alone or blended with conventional diesel) in an unmodified diesel engine. The greenhouse gas emission for biodiesel is 74% lesser as compared to diesel fuel. With the widespread implementation of blending rules, the usage of biofuels rises to 5.5 million barrels of oil equivalent per day (mboe/day) in 2030 from 2.2 mboe/day in 2022. This study explores the numerous rare biodiesel feedstock, production, fatty acid content, physical properties and their effect on diesel engine output behaviour. These resources contain a large amount of free fatty acids and triglycerides which are usually used in the preparation of biodiesel. Since biodiesel has a higher oxygen content and a lower energy content than diesel fuel, it often offers better brake thermal efficiency, brake specific fuel consumption, NOx emission, and decreased HC, CO and smoke emissions at some blending ratio. The exhaust gas recirculation assembly in the engine reduces the NOx emission. The incorporation of non-additive in biodiesel blend acts as a catalyst during the combustion process and improves engine combustion by increasing the surface area of combustion. Biodiesel is clean energy and can be a promising future energy source for diesel engines.