biofuels
In recent years, alternative fuel sources have become a practical reality, next year our government is due to introduce measures to ensure that every litre of fuel sold on the forecourts contains a certain percentage of bio fuel.
What are biofuels?
They are biodiesel and bio-ethanol; liquid fuels made from plant material and recycled elements of the food chain. To a large extent, they are renewable and sustainable. Biodiesel is a diesel alternative. Bio-ethanol is a petrol additive/substitute. They are produced from crops such as cereals, oilseeds, sugar beet and fodder beet.
What are the advantages of biofuels?
They can cut emissions of carbon dioxide, a greenhouse gas, by 50%-60% compared to fossil fuels and so can contribute to meeting UK targets for alleviating climate change.
Biodiesel is biodegradable and non-toxic.
How can they be used?
Biodiesel can be used either as a blend with mineral diesel (5% biodiesel is common in France and has been introduced into the UK) or as a straight fuel. Vehicle manufacturers’ warranties cover use with 5% biodiesel blends. 100% biodiesel must meet the EU quality standard EN 14214. No engine modifications are required and biodiesel can improve engine lubricity when blended with ultra low sulphur diesel (ULSD)
Bio-ethanol can be used as a 5% blend with petrol under the EU quality standard EN 228. This blend requires no engine modification and is covered by vehicle warranties. With engine modification or a vehicle purpose built bio-ethanol can be used at a higher levels, for example E85 (85% bioethanol) is common in the USA.
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
- Aluminium
- Brass
- Zinc
- Lead and lead based solder
- Cork gaskets
- Polyurethane
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 my options?
Working with some of the major oil companies around the world, Tanknology has developed specific protocols for tank inspection and ethanol preparation services, and long with our partners Petroman Ltd and LCM Environmental 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.
The total product solution is as follows:
A site survey carried out by ourselves to determine water content, condition of fuel and chemical deposits.
BioKlenz®, a Petroman product, is added to the fuel to kill any bacteria in the fuel.
LCM’s fuel polishing equipment is used to restore the fuel to its original clean, water and microbe free condition.
Regular inspection of a fuel tank using our Petroscope camera used in conjunction with LCM’s tankers to hold and bottom out tanks, ensures the condition of a tank can be monitored at all times and if the condition deteriorates then this may be reported using a qualified corrosion engineer who can provide detailed analysis of the tank condition and make recommendation as to future action.
If sludge and water is found on inspection then this may be removed and the tank completely cleaned using our newly created sludge removal and tank cleaning equipment. This service allows tanks to be completely cleaned using remotely operated equipment. Use of the Petroscope camera system enables a before and after picture for the client and any external body.
To ensure the fuel remains bacteria free a weaker solution of BioKlenz® is applied to the fuel. This should be recharged on a bi annual basis or when the tank has processed 300,000 litres.
Like all valuable equipment, planning inspection and maintenance is essential to ensure reliable long term performance. Your tanks are no different. Using reliable partners and top quality products and services are your guarantee that your tanks are maintained in optimal condition at a competitive price.
