The Marine industry is prone to fuel contamination, partly because by its very nature, there is after all more water present than in any other industry, but also because vessels can be subjected to differing fuel quality, infected fuel deliveries, large temperature differentials and rough weather (stirring up the sludge in the bottom of the fuel tanks).
In our experience, it’s the marine industry that is best informed of the issues of fuel contamination, and yet it is also our experience that with some notable exceptions, most vessels remain unprotected.
Some captains and engineers do treat fuel with biocides, chemical additives, and yet these can often do more harm than good as they can oxidise the fuel (form large quantities of sediment), they are hazardous to handle and only last for a relatively short period of time. Moreover, they actually don’t deal with the main issue of contamination in the tank, which will still be present, ready to be sucked into the fuel system.
Inside a typical fuel tank, there are layers of contaminate, the fuel pick up is normally set a few centimetres into the tank so that a layer can form without threatening the validity of the supply. But if you factor in some choppy waters, its easy to see how this sludge, water, biomass etc can be pulled into the engine supply pipe.
As an example, here is a typical account from the RNLI
RNLI - St Davids Lifeboat Station, 3rd August 2004 - ALB - Press Release
On Tuesday 3rd August at 9.50 pm the St Davids lifeboat under the command of coxswain Malcolm Gray launched on service to the aid of a 24ft cabin cruiser the 'Catania' which had suffered total engine failure due to fuel contamination. The casualty which was in St Brides Bay had one person on board – a 75 year old gentleman by the name of Mr Doug
The ill-fated journey which began in Brixham, Devon and bound for the west coast of Scotland has been full of difficulties during which time he has made the 'acquaintance' of several lifeboat crews. The lifeboat took the casualty under tow to Neyland marina where repairs will be carried out.
The lifeboat returned to station and re-housed at 2.10 am
Crew : Malcolm Gray, Michael Phillips, David John, Jestyn Martin, William Chant, Ian Gray, Nicholas Phillips
Launchers: Henry Griffiths, David Griffiths, John Bateman, Robin Copley
“It is expected that 4-8% of all diesel engine generators will fail each year due to contaminated fuel. During the plant lifetime, 50% of all diesel engine generators experience a failure. Even in the Nuclear Power Industry, a 2% standby engine generator failure is considered acceptable. Standby engine generator systems don't always exhibit these failures, because they are not run very often.”
This research has been conducted and information provided by an associate of the Institute of Diesel and Gas Turbine Engineers.
The path to clean efficient energy is vital to maintaining the earth’s delicate environmental balance.
From fuel to generation to power, it’s a well established procedure. However efficiencies are lost daily though poor quality fuel, inefficient burning and damaged components.
The UK used the equivalent of 226 million tonnes of oil to generate its power needs in 2007. Imagine how much of that fuel is wasted though inefficient burning in gas turbines.
Contamination can enter fuel during its production process, storage transportation or even during use. For example, sea water can enter the fuel during ocean transportation, condensation, bacterial infection and sludge can form, whilst sediment or fine foreign matter particulate is almost inevitable.
Contaminated fuel can damage gas turbines, contaminates in the oil increase the risk of hot gas path corrosion on the turbine blades. This significantly reduces the service life of the gas turbine and its fuel supply system, as well as reducing its capacity and hence its overhaul period.
The WASP Pure Fuel Systems is the only fuel cleaning equipment on the market today to offer a solution to all these fuel contamination related issues, whilst ensuring your fuel is in optimum condition whilst in storage. This self pumping, automated cleaning solution not only keeps your fuel in pristine condition, but will also increase the efficiency of your turbines through preventative maintenance of the fuel system. Improved efficiency and reliability are a direct result of improved fuel management in this way.
Typical cost savings to be made by removing fuel contaminates:
- Increase of turbine blade lifetime by up to 75%
- Increase in service interval from a typical 4 to 6 years up to 12 years
- Reduction of gas turbine’s “power lost” from 7% to as low as 2%
- 50% reduction in costs for post turbine equipment (e.g. pumps, nozzles, gaskets, etc.)
|W-PFS range features ||Benefits for the gas turbine industry |
|Emulsified water removal - 99% per SAE J1488||Extremely efficient fuel processing|
|Free water removal - 99% per SAE J1839||Lower maintenance costs|
|For all middle distillate fuels||Better fuel economy|
|To 378 lit/min (22,680lit/hr) capacity||Longer engine operating life|
|Particulate removal - 2-3 micron abs.||Less fuel burnt means lower emissions|
|Contaminate efficiency - B5=100||Better economy means less fuel burnt|
The argument for a back-up generator is not too difficult to make.
Companies, government offices, hospitals, utility companies etc. all
have them “in case of” the worst. What if a serious storm were to
knock out the power, what if a fire ripped through the nearby supply
lines, road works can disrupt power, and the simple fact that we do
not have enough energy for our future needs, all contribute to the
requirement for a back-up generator.
If you have critical systems, they need to be protected; you
have to be sure that whatever happens, your system keeps
working, despite the outside world.
Such customers spend hundreds of thousands of pounds to
protect their facilities in case of power failure, and yet the vast
majority ignore the fuel quality in their tanks.
A recent example we carried out was for a telecommunications company. They have about 50,000 litres of fuel for such backup generators, stored in 2 tanks. They were not sure how old it was but were confident enough of its quality as “it had been tested less than a month ago”.
Less than an hour later, one of our cleaning systems had pulled a good 5 litres of sludge and water from one small section of one tank. We estimate we have only tried to clean about 1500 litres of fuel in that time, meaning approximately 0.3% of the fuel was either foreign matter or water. Of the 50,000 litres, this meant there could be more than 150 litres of contamination matter; so much for their previous test giving the fuel the thumbs up.
This level of contamination caused the fuel to oxidise, and allows bacterial infection to spread (see later sections of this document), and may well have damaged the fuel to such an extent that it is un-usable. Moreover, if this contamination had been allowed to enter the main system, it would have clogged the filters in no time, starving the engine of fuel. If the filters were unable to stop it, then without doubt it would have caused significant, if not terminal damage to the generator’s engine.
What is the point of having a generator if you are not going to maintain the one thing that makes it work? Fuel cleaning is essential, without it you are not only risking the investment made in the generator, but the facility you are in. Consider this, how much money would your business lose in 5 minutes without power?
Bulk fuel storage tanks
Fuel degrades over time, forms sediment, oxidises, is susceptible to water, can be infected with a bacterial or fungal “bug” and can have sludge forming in it. Any one of these can cause issues for the user of the fuel, but all of them happen in the bulk storage tank.
As with the marine application description on one of the previous pages, it is the layers of contamination that form in the bottom of bulk storage tanks that can cause the most issues.
On its own, there is a danger of fuel contamination eating away at the tank, this is due to the raised acidic levels the fuel
contamination causes; however the main problem is not in the tank so much as what the tank is feeding. Or to put it another way:
Clean the fuel in the tank – protect the whole system.
In the bottom of a fuel tank, you typically find sludge and water, both are problems that need to be solved. Once introduced through poor venting, or condensation, the water creates the right circumstances for micro-organism growth, from there on the growth of such organisms is almost inevitable unless arrested.
To make matters worst, one of the by-products of such an infection is water from the breakdown of the hydrocarbon fluid. This means that once the cycle of bacterial/micro-organism growth has started, the process is almost a model of perpetual motion. The infection needs water to live, the by product of the infection is water so more contamination grows, generating more water and so on.
The sludge found in tanks is the first sign most users detect of fuel infection; yet it is typically not the infection but rather the infection by-product, think of it as eaten hydrocarbons, and other waste matter. This sludge is typically dark brown or black, waxy in texture and foul smelling (a rotten egg smell is the most common description).
An infection, once in the tank can remain dormant for many years. It only needs the right conditions to germinate and grow. That is water (to live in) the right temperature (10-40 degrees C) and a food source (the fuel’s hydrocarbons). If one of these conditions is not present, then the infection cannot grow, however it can remain dormant – for example on dry tank sides. Re-wet the sides and you can re-introduce the infection.
So in summary – water, sludge and other contamination is active in most if not all tanks. Its removal is vital to protect the tank from corrosion, but moreover to protect the systems that the tank’s fuel will be supplying. Cleaning the fuel in the tank is the simplest way to achieve this.