Uma avaliação holística de aspectos tecnológicos e ambientais da produção de biodiesel de diferentes matérias-primas no Brasil

Abstract

Considering the importance of biodiesel production in Brazil, especially with the increase of the obligatory biodiesel blending to diesel, this work aims at comparing the production of biodiesel from two raw materials available in the country, through the three production routes different. The Life Cycle Assessment (LCA) was the methodology used for this study covering the stages of obtaining the raw material until the production of biodiesel, an approach called "Cradle to Gate". Six scenarios were determined from soybean and palm raw materials using three technological routes: homogeneous transesterification, heterogeneous transesterification and enzymatic transesterification. A functional unit of 1 MJ was established using the software SimaPro 7.0 ® and the method of evaluation of the environmental impacts adopted was IMPACT 2002+. An indicator was calculated to characterize the biodiesel renewal, in addition, the Cumulative Energy Demand method was used to calculate the energy efficiency of the biodiesel life cycle (LCEE). All scenarios are energy efficient and have positive values indicating biofuel renewal. The scenario of the heterogeneous transesterification of palm oil has the best performance for both indicators. Among the raw materials, the results indicated soybean with greater environmental impacts. For soybean biodiesel the stages with the greatest contribution are the cultivation stage due to the higher emissions due to the consumption of fertilizers and fossil fuels and the stage of extraction of the oil by the use of chemical solvent. For the palm the stages of cultivation and transesterification are highlighted, mainly by the production and use of steam. Homogeneous transesterification had the greatest impact in 9 of the 15 categories of environmental impacts evaluated, as well as in 3 of the 4 categories of environmental damages. The production of biodiesel via heterogeneous transesterification from palm oil presented the best performance.