Avaliação comparativa de estudos de análise do ciclo de vida da produção de biodiesel

Abstract

Since the first petroleum crisis in the late 60's until the present day, there is a great concern with new alternative energy sources that pollute less, have lower costs and are renewable. In this context, biofuels emerged. Biodiesel is one of those biofuels that have attracted attentionof many people because it is a renewable, biodegradable, nontoxic and virtually free of sulfur and aromatic composts. Moreover, biodiesel has a more favorable combustion emission profile than diesel. In Brazil, there are laws that require the addition of 5 to 20% biodiesel with petroleum diesel. And there is a tendency to increase this percentage. In this study was made a comparative analysis of the environmental impact of biodiesel production by different processes, using data obtained from Life Cycle Analysis (LCA) performed with the use of different oils, alcohols (methanol and ethanol) and catalysts (acids and alkaline). It is noteworthy that LCA is an important tool used to evaluate the environmental impacts of a product, service or process. This analysis is made taking into account the limits of the system defined by the methodology of the study, which may be from the extraction of raw materials to final disposal of the product. The objective of this study was to evaluate the production process which represents the lowest environmental impact throughout the life cycle of this biofuel. We considered four main categories of impacts, including human health, ecosystem quality, climate change and natural resources. The results showed that methanol is the most widely used alcohol for biodiesel production because it is cheaper. In the case of oils, as expected, waste cooking oils brought less damage to the environment. Furthermore, among the catalysts used in the reactions, thealkaline catalyst is more efficient in many aspects that have been compared, but the process without use of catalyst was the most environmentally favorable alternative.