3 rd International Conference on Multidisciplinary Research & Practice Page | 118 Volume IV Issue I IJRSI ISSN 2321-2705 Estimation of Vapor Pressure of Fatty Acid Ethyl Esters (Biodiesel) Parag Saxena 1 , Milind H. Joshipura 2 , Mehul Mehta 3 , Prasann Patel 4 1 Chemical Engineering Department, Institute of Technology Nirma University, Ahmedabad, Gujarat, India 3&4 Student, Chemical Engineering Department, Institute of Technology Nirma University, Ahmedabad, Gujarat, India Abstract— As the petroleum fuels are used at a rapid rate there is a need for alternative fuel to meet the rising demands. Biodiesel is a promising alternative for petro-diesel. Biodiesel is basically a mixture of fatty acid alkyl esters (FAAE) obtained by the trans-esterification of vegetable oils/animal fats using an alcohol, such as methanol or ethanol, in the presence of a catalyst. Vapor pressure of biodiesel fuel is an important property and experimental determination of vapor pressure is cumbersome and time consuming. Therefore vapor pressure needs to be estimated. There is good volume of work done for the vapor pressure of Fatty acid methyl ester (FAME), but less work is done for fatty acid ethyl ester (FAEE). Therefore in this work vapor pressure of 11 FAEE’s was estimated by two methods, method of Othmer and Yu and method of Yuan. Both the methods gave good estimation of vapor pressure, but the method of Othmer and Yu is simple to apply in comparison to method of Yuan and it can be used even for lesser number of data points. Therefore as a part of this study we propose the method of Othmer and Yu for the estimation of vapor pressure of FAEE. Keywords—Biodiesel, FAME, FAEE, vapor pressure I. INTRODUCTION s the petroleum fuels are used at a rapid rate there is a need for alternative fuel to meet the rising demands. Biodiesel is a promising alternative for petro-diesel. Biodiesel is basically a mixture of fatty acid alkyl esters (FAAE) obtained by the trans-esterification of vegetable oils/animal fats using an alcohol like methanol in the presence of catalyst. Jatropha, soybean, rapeseed, sunflower are the most common feedstock used for production of biodiesel. Biodiesel is biodegradable, non-toxic and gives lower emissions. It mixes with petro-diesel in any composition and hence suitable for diesel engine [1],[2]. Vapor pressure is an important property of biodiesel fuel. Low vapor pressure can lead to problems like poor atomization and poor combustion. As biodiesel fuel have low vapor pressure such problems would be there. Therefore vapor pressure of biodiesel becomes an important property. [2]. The experimental determination of vapor pressure of biodiesel is difficult as biodiesel decompose before reaching their critical temperature and therefore the estimation of vapor pressure becomes important [3]. Many researchers have estimated vapor pressure of FAAE by various methods. The work is summarized below in Table 1. Table 1 Literature review on vapor pressure estimation Researcher Biodiesel (no of FAAE’s) Estimation methods Ref. Yuan et al. FAME (14) Antoine equation and group contribution methods [4] Samuel et al. FAME (3) Yuan, Ceriani and CPA EOS. [2] Yang et al. FAME (5) Lee-Kessler, Ambrose Walton, data compilation method [5] Anand et al. FAME Lee-Kessler, Tu, and Pitzer [3] Saxena et al. (our work) FAME (9) and FAEE (4) Othmer and Yu, Yuan and many others [6] Much of the reported work is on the estimation of vapor pressure of fatty acid methyl esters. Our previous work [6] was based on the estimation of vapor pressure of 4 ethyl esters (FAEE), but in this study we have estimated the vapor pressure of 11 FAEE by two methods which have been found good for the estimation of vapor pressure of FAEE. One method is method of Othmer and Yu which was proposed in our earlier work [6] and the second one is method used by Yuan et al. [4]. Therefore in this work we have compared these two methods to estimate vapor pressure of FAEE. II. METHODS FOR ESTIMATION OF VAPOR PRESSURE A. Method of Yuan Yuan estimated the vapor pressure using Antoine equation. This equation has been widely used in the oil industry, because of its simplicity and accuracy. This is given by ) / ( ln T C B A P sat    ……(1) Where sat P is vapor pressure (Pa) at temperature T(K), other parameters are correlation coefficients, and Yuan estimated the value of these parameter for various types of FAAE’s. A