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Introduction Due to pressures to reduce emissions last year the EU passed a new fuel directive which requires all Non-road mobile machinery - construction, agriculture, mobile gen-sets and so on - to use Ultra Low Sulphur Diesel. This causes problems with the diesels lubiricity, which is then restored by adding bio-diesel, which cases several problems concerning fuel contamination. Causes & Problems Bio-diesel has an inferior level of oxygen stability compared to normal petro-diesel. This means that when the ultra low sulphur diesel comes into contact with oxygen in the fuel tank, it will cause a chemical reaction which creates peroxide. The peroxide then allows organic acids to form which, in turn, cause gums and resins to form in the fuel, potentially blocking the engines fuel filter and starving the engine of fuel. The other problem bio-diesel causes is water contamination, caused by its increased hygroscopy compare to petro-diesel, resulting in it absorbing a much larger amount of water. During engine operation, the temperature of the fuel will fluctuate, which causes the water to precipitate out of the fuel, forming a layer of free water at the bottom of the tank. This free-water can cause 2 problems; firstly it can flow into the engine and cause excessive wear and possibly severe damage, and secondly promotes the formation of "diesel bug". Diesel bug is the term used to describe the large collection of bacteria, mould and yeast that can live inside fuel tanks. They feed on the hydrocarbons in the diesel and live in the free water in the tank. This not only degrades the fuel, but the bug also produces a large quantity of biomass, forming a layer between the free-water and the diesel, either blocking the engines fuel filter and starving the engine of fuel, or passing through it and causing excessive engine wear. Treatments Many of these issues can be prevented from occurring by following engine manufacturers "good housekeeping" advice which includes: - Where possible purchase fuel from reliable sources
- Ensure your fuel tanks are regularly maintained and leak-free
- Always follow recommended tank refilling methods
- Store fuel in a cool place, where possible
- Keep fuel tanks as full as possible to prevent water from condensing due to humidity
- Filter fuel whenever it is moved
- Employ an 'on-tank' filtration (fuel polishing) system to remove water and other contamination.
- Consider the use of a fuel additive to prevent fuel oxidation and a fuel biocide to minimize microbial growth
- Introduce a regular fuel biocide. A fuel biocide contains chemicals that kill diesel bug inside the fuel tank. A large "shock dose" should be applied to kill existing bug, followed by regular smaller doses to prevent it from reoccurring.
By removing and preventing diesel bug from occurring, you can ensure a longer life for your diesel engine. By IPU Group The IPU Fuel Conditioning division provides a complete range of products and services designed to detect and eradicate harmful diesel fuel contamination. The range includes products for bulk fuel storage, on application fuel system protection and mobile solutions.
Related Articles -
diesel bug, fuel polishing, fuel condtitioning, fuel contamination, fuel biocide, diesel fuel contamination, diesel biocide,
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