MICROBIOLOGICAL PROBLEMS IN DISTILLATE FUELS

Microbial contamination, fouling and spoilage of distillate fuels is as well documented phenomenon; the incidence has increased in recent years largely due to changes in fuel and additive chemistry which have made the product much more nutritious to microorganisms. The microbes (bacteria, yeasts and moulds) initially grow in associated free water but later disperse in the fuel phase. Here their ability to survive in fuel varies; they may die within hours or weeks, but the dead organisms do not disappear, neither do their products; they still foul the fuel. Microbes tend to aggregate at the fuel water interface, drawing their nutrients from the fuel whilst remaining bathed in water. Spoilage is associated with changes off specification including increase in sulphide, filterability changes, and water separation problems due to microbial surfactants. Fitness for use is affected by injector malfunction and filter plugging (particularly due to bacterial 'cling film' like polymers) and in the long term, corrosion. Microbes entrain other particulates hence increasing fouling. The consequences to the fuel user can be dramatic. Within hours of loading contaminated fuel the injectors and filters may be completely blocked. The consequences of a tanker loading a contaminated cargo may be no less catastrophic as there are very large financial implications. There are many simple clues which give the engineer an indication that there are microorganisms in the fuel and there are a variety of onboard proprietary tests which back-up visual impressions. Anti-microbial measures fall into several categories, such as good housekeeping (including the use of preservatives), and fuel system/cargo tank decontamination. Practical suggestions are given for reducing the risk of problems occurring and also for onboard action if a problem occurs.

• Supplemental Notes:
  • Inst Marine Engrs Trans, v 104, Pt 4, 1992, p 119 [9 p, 12 ref]
• Authors:
  • Hill, E C
  • Hill, G C
• Publication Date: 1992

Language

• English

Subject/Index Terms

• TRT Terms: Distillates; Fuels
• Uncontrolled Terms: Microbial contamination
• Old TRIS Terms: Distillate fuels; Fuel oil quality; Microbial fouling
• Subject Areas: Energy; Marine Transportation;

Filing Info

• Accession Number: 00704143
• Record Type: Publication
• Source Agency: British Maritime Technology
• Files: TRIS
• Created Date: Aug 14 1995 12:00AM