Comparison of potential environmental impacts on the production and use of high and low sulfur regular diesel by life cycle assessment

Abstract

This paper provides a comparative analysis using the concept of life cycle assessment (LCA), between high-sulfur (3000 ppm) and low-sulfur diesel (500 ppm) diesel. The comparative LCA considers the stages of production, transport and oil refining , as well as the transport of refined products and their respective end use. This last stage of the life cycle is important for the analysis of potential environmental impacts, due to sulfur oxide (SOx) emissions, which contribute to the formation of acid rain, damage air quality and the ecosystem (land and water acidification), causing gradual damage to human health and the environment. Therefore, comparative LCA identifies critical points from the environmental perspective, weighing the contributions of pollutants (NO2, CH4 and CO2) known as greenhouse gases (GHG) and criteria pollutants (CO, SOX, NOX, VOC's and PM). Simapro 7.2® was used to simulate and evaluate potential environmental impacts generated during the production and use by end consumers of the two fossil fuels. In order to evaluate the impact categories, two methods available in said calculation tool were selected: the first is the IPCC-2007 (GWP-100years), which estimates the carbon footprint and the contributions of each stage of the production chain to the "Global Warming" effect. The second method of evaluation is the Impact 2002+, which assesses the various contributions to the categories of toxicity to "Human Health", "Ecosystem Quality", "Climate Change" and "Depletion of Natural Resources". Thus, the preliminary results of comparative LCA show a slight increase in the carbon footprint (total emissions of CO2 equivalent in the productive chain) of low-sulfur diesel, approximately 3.8% compared to high-sulfur diesel, as a result of the increased emissions generated by the operation of the hydrogenation plant. However, low-sulfur diesel achieves a significant reduction of about 80% in comparison with high-sulfur diesel, in terms of damage to "Human Health" and "Ecosystem Quality". On the contrary, there was an increase of 2% and 6% in the categories of "Climate Change" and "Depletion of Natural Resources", respectively. Finally, despite the minor increase in the carbon footprint, although with remarkable reductions in "Ecosystem Quality" and "Human Health", the production and use of low-sulfur diesel has a single score of environmental impact equivalent to 0.23 milli points (mPt) compared to the single score obtained by high-sulfur diesel of 1.23 (mPt).