Assessment of alternative diesel fuels: microbiological contamination and corrosion under storage conditions

Why it matters

According to the researchers, the microbial contamination of hydrocarbon fuels has been recognized as a problem, and it is the main cause of clogging of fuel lines and filters, product deterioration and corrosion of metals during hydrocarbon extraction, production, distribution, and storage. The major limitation for microbial activity in fuels is the presence of water. Moreover, the susceptibility of hydrocarbons to aerobic and anaerobic biodegradation is well known and the subject has been reviewed by previous research studies. Biodiesels are inherently more susceptible to microbial degradation than typical hydrocarbon fuels since methyl esters are hydrolyzed with ease under aerobic or anaerobic conditions. The authors aimed to characterize the corrosion and electrochemical behavior of storage and fuel tank alloys in the presence of alternative fuels over time, and to determine the microflora and chemistry of as-received fuels as a function of biodiesel content and storage time.

Reference

The article appears in the 6th issue of the Biofouling journal (volume 26, issue 6, pages 623-635). Authors: Jason S. Lee, Richard I. Ray, and Brenda J. Little.

Abstract

Experiments were designed to evaluate the nature and extent of microbial contamination and the potential for microbiologically influenced corrosion of alloys exposed in a conventional high sulfur diesel (L100) and alternative fuels, including 100% biodiesel (B100), ultra-low sulfur diesel (ULSD) and blends of ULSD and B100 (B5 and B20). In experiments with additions of distilled water, all fuels supported biofilm formation. Changes in the water pH did not correlate with observations related to corrosion. In all exposures, aluminum 5052 was susceptible to pitting while stainless steel 304L exhibited passive behavior. Carbon steel exhibited uniform corrosion in ULSD and L100, and passive behavior in B5, B20, and B100.