Production of palm and Calophyllum inophyllum based biodiesel and investigation of blend performance and exhaust emission in an unmodified diesel engine at high idling conditions

Rapid depletion of fossil fuels, increasing fossil-fuel price, carbon price, and the quest of low carbon fuel for cleaner environment – these are the reason researchers are looking for alternatives of fossil fuels. Renewable, non-flammable, biodegradable, and non-toxic are some reasons that are making biodiesel as a suitable candidate to replace fossil-fuel in near future. In recent years, in many countries of the world production and use of biodiesel has gained popularity. In this research, biodiesel from palm and Calophyllum inophyllum oil has been produced using the trans-esterification process. Properties of the produced biodiesels were compared with the ASTM D6751 standard: biodiesel standard and testing methods. Density, kinematic viscosity, flash point, cloud point, pour point and calorific value, these are the six main physicochemical properties that were investigated. Both palm biodiesel and Calophyllum biodiesel were within the standard limits, so they both can be used as the alternative of diesel fuel. Furthermore, engine performance and emission parameters of a diesel engine run by both palm biodiesel–diesel and Calophyllum biodiesel–diesel blends were evaluated at high idling conditions. Brake specific fuel consumption increased for both the biodiesel–diesel blends compared to pure diesel fuel; however, at highest idling condition, this increase was almost negligible. Exhaust gas temperatures decreased as blend percentages increased for both the biodiesel–diesel blends. For low blend percentages increase in NOX emission was negligible but as blend percentages increase, emission increased significantly. CO and HC emission for both biodiesel–diesel blends were lower compared to pure diesel fuel. 20% Calophyllum biodiesel–diesel blends emitted lowest HC and CO emission.