Bio Fuel Contamination
Tank cleaning is our bread and butter at LCM and has been for 25 years. We have cleaned all sizes of tanks containing all sorts of liquids and solids.
But a recent tank clean for one of our clients highlighted some of the serious issues involved with modern Bio Diesel.
We have a few words of warning, well a video to be precise.
What are the disadvantages with biofuels?
Producing biofuels costs (pre tax) about twice as much as fossil fuels does to produce.
Several of the outstanding ethanol fuel issues are linked specifically to fuel system materials. Fuels with more than 10% ethanol are not compatible with non E85-ready fuel system components.
Certain materials commonly used in the storage and dispensing of existing fuels can be affected by ethanol blended fuels, such as
- Lead and lead based solder
- Cork gaskets
It will be essential that a full survey of the existing site be carried out to identify any components that may be incompatible with bio-fuels.
The largest concern to bio-ethanol is water. Ethanol and water are simply not compatible. It takes a small amount of water to cause what is known as “phase separation”.
When water does contaminate ethanol blended fuel, the water dissolves into the ethanol and disperses throughout the tank. Once it exceeds its maximum tolerance, the alcohol/water mixture will separate from the fuel. As little as 50mm of water in a 38,000 litre tank can start phase separation.
Depending upon the conditions, up to 80% of the ethanol will separate from the fuel, forming two separate layers in the tank: petrol on top of ethanol-rich water. Phase separated product cannot be re-blended on site and will need to be removed for reprocessing or disposal.
Debris or particulates create similar problems in tanks containing ethanol blended fuels. For this reason it is critical that all tanks receiving ethanol fuels should be carefully inspected prior to the first introduction of fuel to ensure that there is no water or debris present.
The ethanol in bio-ethanol is ethyl alcohol and will act as a cleaning/scouring agent when introduced into existing UST’s therefore any remaining debris will be held in suspension within the new fuel. Biodiesel is a better solvent than existing diesels, and has been known to break down deposits of residue and sludge in UST’s.
The types of problems that occur when water or debris contaminates ethanol-blended fuels include;
- Fuel octane ratings to levels below specification
- Filter clogging, requiring frequent filter replacement
- Spoiled fuel
- Customer vehicle driveability complaints and/or damage
More than half of UST’s inspected prior to the introduction of ethanol-blended fuels require some level of preparation services in order to avoid some or all the above problems.
It is a fact that all UST’s contain some level of water. That water must be removed before the introduction of ethanol-blended fuel. Many operators will rely upon their Automatic Tank Gauge (ATG) or their dipstick and water detecting paste to tell them whether they have water, then pump it out until these devices tell them no water remains.
This is a mistake. These tools are not sophisticated enough to ensure there is no water in the tank, the condition necessary before introducing ethanol. In fact, conventional water finding paste will not detect a phase separated bottom layer quickly enough to react to it before problems occur. In our experience, more then half the time, unlevel tanks result in water collecting in an area of the tank that is not detected by the tank gauge or dipstick. There is no way to know that from above ground with a conventional water detecting device.
Bio diesel may contain small but problematic quantities of water, it is said to be hydroscopic to the point of attracting water molecules from atmospheric moisture. These molecules can act as a emulsifier, allowing water to mix with the biodiesel. The presence of water is a problem because;
- Water reduces the heat of combustion of the fuel. This means more smoke, harder starting, less power
- Water causes corrosion of vital fuel systems componants: fuel pumps, injector pumps, fuel lines, etc.
- Water accelerates the growth of microbe colonies, which can severly affect your fuel system
What are the options?
Working with some of the major oil companies around the world, LCM Environmental and Tanknology have developed specific protocols for tank inspection and ethanol preparation services we have developed a complete fuel management programme to provide peace of mind to any operator of a fuel installation whether they are having blocking filter issues or are intending to convert to bio-fuels.