tailieunhanh - Handbook of plant based biofuels - Chapter 15

15 Biodiesel Production With Supercritical Fluid Technologies Shiro Saka and Eiji Minami contents Abstract 213 Introduction . 214 Supercritical Fluid 214 One-Step Supercritical Methanol Method (Saka Process) . 215 Two-Step Supercritical Methanol Method (Saka-Dadan Process) . 217 Properties of Biodiesel 221 Conclusions and Future Perspectives 222 References 223 AbstrAct At present, the. | 15 Biodiesel Production With Supercritical Fluid Technologies Shiro Saka and Eiji Minami CONTENTS Supercritical One-Step Supercritical Methanol Method Saka Process .215 Two-Step Supercritical Methanol Method Saka-Dadan Process .217 Properties of Conclusions and Future ABSTRACT At present the alkaline catalyst method is applied commercially to produce biodiesel. However the process is not simple and not applicable to wastes of oils and fats. Therefore a one-step supercritical methanol method the Saka process was developed as a noncatalytic process. In this process even wastes of oils and fats that are high in water and free fatty acids can be converted to biodiesel. However the reaction conditions are drastic 350 C 20 MPa thus a special alloy such as hastelloy is required for the reaction vessel. Additionally the biodiesel produced is thermally deteriorated. Therefore to realize milder reaction conditions a two-step supercritical methanol method the Saka-Dadan process was developed which consisted of the hydrolysis of oils and fats in subcritical water and subsequent methyl esterification of the fatty acids produced in supercritical methanol. In this process milder reaction conditions 270 C 10 MPa can be realized using ordinary stainless steel instead of a special alloy. Moreover due to the removal of the glycerol after the hydrolysis process the biodiesel satisfies most of the requirements of the EU and . standards. 213 2009 by Taylor Francis Group LLC 214 Handbook of Plant-Based Biofuels INTRODUCTION TG MeOH DG FAME DG MeOH MG FAME MG MeOH . G FAME FIGURE Three step-wise transesterification reactions of triglyceride. Biodiesel fuel which is defined as fatty acid methyl ester FAME is one of the most promising bioenergies used as a substitute for fossil diesel and can be produced commercially with methanol by transesterification of .