Use of waste materials for biodiesel production

Use of waste materials for biodiesel production Rosa Vitielloa, Antonio Buonerbab, Riccardo Tessera, Martino Di Serioa, Alfonso Grassib, Giuseppina Carotenutoa, Salvatore Mallardoa, Elio Santacesariaa aDipartimento di Chimica, Università di Napoli “Federico II”, Via Cinthia, 80126 Napoli, Italy bDipartimento di Chimica e Biologia, Università degli Studi di Salerno, via Ponte don Melillo, 84084 Fisciano (SA), Italy Waste raw materials obtained by several sources of food and by agro industries could be used for biofuel production. In the last years, these topics have growing in interest according to the last EU legislation on biofuels sustainability. Our research, related to AGROPROM national project of the Italian Ministry of Agriculture, is focusing on the development of new technologies to obtain biodiesel from agro-industrial wastes, in particular from oleins, that is mixtures of free fatty acids (FFAs) and triglycerides. A preliminary study on the sources of oleins in Europe will be reported. These raw materials cannot be processed in the classical biodiesel plant, because, the usual basic catalyst cannot be employed for promoting transesterification reaction. At this purpose, we are studying an innovative way to produce biodiesel by using these waste feedstock performing, before the esterification, a reaction of FFAs with glycerol and submitting then the whole mixture to transesterification with methanol. The esterification of FFAs with glycerol provided the possibility to operate at relatively high temperature and atmospheric pressure removing, by stripping, the water formed during the esterification reaction, shifting the chemical equilibrium to the right. The mixture of monoglycerides, diglycerides and triglycerides, that can be obtained by esterification with glycerol, can be subsequently submitted to transesterification with methanol to produce biodiesel in the usual way. As reported in the literature, the most employed catalysts to perform the esterification reaction, are homogeneous mineral acids and acid ion exchange resins [1-3]. Although a heterogeneous catalyst is more convenient, because, can be more easily separated and recycled, commercially available acid ion exchange resins are limited in the use because cannot be used at temperature greater than about 120°C. Therefore, other more temperature-resistant sulphonic resins, Nafion, and H2WO4/SiO2, have been tested in the described esterification reaction and their performances have been compared with the ones of sulphuric acid. At last, different heterogeneous catalysts for transesterification have also been studied in a continuous micropilot plant reactor with encouraging results. [1] Y. Pouilloux , S. Abro, C. Vanhove, J. Barrault Journal of Molecular Catalysis A: Chemical 149 _1999. 243–254 [2] Franz J. Luxem, US 6,822,105 B1 [3]Parodi, Augusto, WO 2008/007231 A1