Towards a "greener" generation of biodiesels

Abstract

In the world, oil provides 96% of transport needs, which mobilize 65% of the oil consumed and contribute 20% to CO2 emissions. One of the alternatives to reduce the consumption of fossil resources is the use of "biofuels". These biofuels are classified into three successive generations. The first generation biofuels come from the food parts of field crops: bioethanol and biodiesel. Second generation "advanced"biofuels come from lignocellulosic resources (wood, agricultural residues, etc.) valued either as bioethanol or synthetic hydrocarbons. A third generation is based on the culture of micro-algae producing fatty acids transformed into biodiesel. The first generation biodiesels, like those of the second and third generations, are subject to certain criticisms in particular the LUC (Land-Use Change) and the food versus energy competition. The objective of this work is to examine the interest of two promising ways. Biodiesel based on dedicated crops lead to reduced environmental impacts but play a role in the problem of LUC. While those based on residues are not part of the problem and show levels of reduction of greenhouse gas emissions between 83 and 90% against 60 to 80% for a conventional biodiesel compared to a fossil diesel fuel. Butyl esters of used edible oils and animal fats are displayed as "greener"biodiesels and represent an opportunity for second generation biofuels and for a greener oleochemistry.