Resumo:
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.
