Predicting Fuel Properties of Partially Hydrogenated Jatropha Methyl Esters Used for Biodiesel Formulation to Meet the Fuel Specification of Automobile and Engine Manufacturers

Abstract

Partial hydrogenation was conducted on Jatropha methyl esters (JME) and was performed in a batch reactor in the presence of a palladium-on-carbon (Pd/C) catalyst. After 2 h of hydrogenation, the fatty acid methyl esters (FAME) profile of the partially hydrogenated Jatropha methyl esters (PHJME) was determined. The key properties of the PHJME such as oxidation stability, viscosity, cetane number, cloud point, pour point and cold filter plugging point (CFPP) were determined based on the FAME profile and using the empirical models which are available in the most recent literature. After partial hydrogenation, there was a decrease in the polyunsaturated content of about 9%. The calculation results showed that the oxidation stability improved from 4.16 h with JME to 5.99 h with the PHJME. The cetane number of the PHJME (57.65) was higher than that of the JME (55.87). Compared to the JME, the PHJME were found to have similar viscosity but inferior cloud point, pour point and CFPP. Therefore, to meet the requirement of the automobile and engine manufacturers that the oxidation stability of biodiesel should have a minimum value of 10 h, antioxidant should be added to PHJME. Based on the analysis of the kinetic model for the consumption of antioxidant, pyrogallol and propyl gallate were the best antioxidants for both the JME and the PHJME.