OXIDATION STABILITY OF DIESEL AND BIODIESEL IN NORTHERN BRAZIL: CHALLENGES AND RISKS TO FUEL QUALITY

Abstract

This study analyzes the oxidation stability of diesel, biodiesel, and their blends in the Northern Region of Brazil, focusing on the cities of Manaus and Belém. The main objective is to comparatively evaluate the oxidative behavior of different samples of diesel, biodiesel, and blends, highlighting the risks to vehicles and engines under typical conditions in the region. The methodology combines a literature review and field research, including sample collection from local distributors and laboratory tests according to EN 14112 and EN 15751 standards. The results show that, although mineral diesel exhibits high resistance to oxidation, increasing the biodiesel content in the blends significantly reduces oxidative stability, with averages of approximately 13 h for biodiesel and 20 h for B15 diesel. In Manaus, river transport and high humidity favored lower values compared to Belém. The discussions highlight that less stable fuels increase acidity, stimulate corrosion, promote microbial growth, and shorten the product's shelf life. It is concluded that the advancement of mandatory biodiesel blending demands additive strategies, continuous monitoring, and updating of technical standards in order to ensure adequate performance and reliability of the quality of these fuels in the Brazilian context.