The Total Fuel Solution package:
- Fuel Testing
- Fuel Recirculation & Recovery 'Fuel Polishing'
- Uplifting contamination
- Tank Cleaning if required
- Fuel Conditioning
- Maintenance and Prevention
Growth of microorganisms in petroleum products has been recorded since 1895, causing fouling, malfunction and corrosion in storage tanks, equipment, pipelines, filters and engines.
The microbes feed on the fuel which enables them to multiply and form colonies. Microbial contamination is most commonly seen as sludge that forms in the bottom of storage tanks and accumulates on filters.
This sludge affects engine operations in several ways:
- it blocks filters
- causes poor fuel combustion leading to fuel inefficiencies
- contributes to poor emissions (seen as black exhaust smoke)
- causes incorrect fuel gauge storage readings
The life cycles of bacteria of a variety of types, both aerobic and anaerobic, produce corrosive acids and sticky sugars that further impinge on engine and system functions:
- organic sulphurous and sulphuric acids corrode fuel tanks, pipelines, rubber seals, ‘O’ rings and hoses
- sugars caramelise in and on fuel injectors which adversely affects the fuel spray pattern and can ‘glue’ together injector parts to cause failure of the injectors.
Petroleum diesels typically hold 60ppm of suspended water. At this level, the water is almost insignificant. Provided the fuel is regularly used and replenished the aforementioned microbial contamination problems do not occur.
Bio-diesels typically hold up to 25 times more suspended water than petroleum diesel. The worldwide introduction of bio-diesel in recent years, in pursuit of conserving fossil fuel, carbon neutral targets and energy security, has brought a mariner’s fuel problem on land: bio-diesel is a perfect habitat for vigorous microbial growth.
The Lloyds Register published a technical paper (Paper Nº4, Session 1994-95) highlighting critical levels of bacteria in fuel. Less than 500cfu (colony-forming units) per litre is acceptable. At the 500-1000cfu level, Lloyds warns “microbial proliferation occurring” and at over 1000cfu “microbial proliferation; operational problems; investigate thoroughly; use anti-microbial treatment”.
In petroleum diesel the critical levels beyond 500cfu would rarely be seen outside of marine or long term storage situations. Bio-diesel is a different matter – the higher water content provides the microbes with a very attractive environment.
Consequently the amount of exposure to condensation, leaks or time in undisturbed storage before proliferation begins, is dramatically reduced. Today’s biofuels deteriorate much faster than their petroleum forebears.
Colony Forming Units of bacteria grow on the water-fuel interface becoming heavier until they drop out of the fuel to the bottom of the tank where bio-films and sludge quickly form.
The bacteria feeds on the fuel – but the microbes do not eat ‘all’ of the fuel: they break down the carbon chains which reduces the combustible properties. This leads to:
- poor starting (or failure to start at all)
- excessive smoke
- reduced power output
MICROBIAL CONTAMINATION IS NOT LIMITED TO DIESEL
Aviation jet fuels are subject to the same problems which are the reason for the aviation industry’s rigorous fuel management regimes. Gasoline - petrol - has, until the introduction of bio-content, been the only fuel unaffected by microbial contamination but petrol containing bio-ethanol suffers too.
Universal use of biofuels is at least as profound a change to fuels as the switch to unleaded petrol in the 1990s. Fuel quality management is no longer something that rests only with refineries, ship owners and airlines: microbial contamination affects everyone.
ATP or Adenosine Triphosphate, is an energy carrier located within living biological cells that manages all biological functions, such as food consumption, maintenance, and reproduction. It is a molecule so central to microbial life that its measurement is directly related to biomass energy level.
Without ATP there would be no life. ATP is found in any living life form, from a simple one–celled organism to you and I. If there are microorganisms present, there is ATP.
Within a fuel sample containing microorganisms, there are two types of ATP:
- Intra-cellular ATP – ATP contained within living biological cells. This is also known as Cellular ATP (cATP).
- Extra-cellular ATP – ATP located outside of biological cells that has been released from dead or stressed organisms. This is known as Free ATP (fATP).
Recirculation & Recovery 'Fuel Polishing'
When microbial activity is identified in a fuel tank, the Recirculation & Recovery 'Fuel Polishing' machine is the fastest means of decontaminating and returning the fuel to its optimum clear and pure condition.
Contamination at the bottom of the tank can be quickly uplifted and removed by our own purpose built petroleum regulated vehicles. Good fuel can then be uplifted, re-circulated and recovered, minimising the process time and ensuring that all of your fuel is filtered.
Tank Cleaning (if required)
Our tank cleaning operatives are specialists in their field. They are highly trained and are able to internally clean above or underground tanks, this in itself gives you the peace of mind that your tanks are completely cleaned prior to your fuel going back into the tank.
Above are before and after photos of a heavily contaminated above ground diesel tank where the fuel was uplifted using one of our own petroleum regulated tankers and held for safe keeping whilst the tank was internally cleaned by our specialist tank cleaning crew. Once the tank was clean the uplifted fuel was then filtered back into the tank via our fuel remediation unit hence removing all prior contamination and resulting in minimal fuel losses to the customer.
Fuel Conditioning System
For ongoing, permanent protection fuel needs to pass through a Conditioner at least once every 28 days. Conditioners are fitted in suction lines immediately after the outlet of the fuel tank, and ahead of any other devices such as particulate filters, pumps and meters. In certain particularly dirty applications it is prudent to have a strainer-type filter ahead of the Conditioner.
In a recirculating system (most modern engines have a return line from the fuel injection to the tank) this condition is easily met. These are the easiest systems to protect - microbial contamination cannot take hold with a Conditioner in the loop.
In a non-recirculating system a Conditioner at the tank outlet will, at all times, protect whatever lies downstream - filters, engines, customer fuel tanks and so on.
For fuel storage applications, protection of the tank inlet with a Conditioner will stop contamination entering the tank.
A Conditioner on the outlet ensures that all fuel drawn from the tank is free from microbial contamination.
However, fuel that remains static in a tank for over 28 days is susceptible to recontamination because tank vents allow condensation to enter. Periodic cleaning of the tank with a recirculation and recovery machine will remove any microbial contamination from the fuel stock. Levels of microbial contamination in storage tanks can be monitored by conducting ATP tests on fuel samples drawn from the tank.