Clogged fuel filter
Diesel Fuel "Algae" Causes & Effects

Most people who operate and maintain Diesel engine systems are familiar with the black slimy material frequently seen in their fuel filter elements, and found in the bottoms of their fuel tanks.  It is known by many names e.g. algae, mud, sludge, dirt, BS&W , and many other unsavory sounding terms - all of which are misnomers.  Many people think this material is some sort of microbe, thus in the marine industry, it is most commonly called "algae". While bacteria and other microbes contribute to and accelerate this process, sludge is no more bacteria than milk that has turned into cottage cheese - it's still milk, only in a physically different form -- Diesel fuel forms wax and asphalt, not "algae".


To understand the source and nature of this material, it is helpful to know a little about how Diesel Fuel and other distillate products are made in today's modern refineries.  In the "old days" (15 - 25 years ago) processing of crude oil into the light distillate products we all know as gasoline, Kerosene, home heating oil, jet fuel, and diesel was basically done through heating the crude oil. At different boiling points, the various fractions of the crude were evaporated then condensed and sent to a storage tank for distribution.  The distillate product, diesel fuel included, were fairly stable products with shelf life measured in the several months range.


The residual oil left over after the distillation process, approximately 50% of the barrel of crude that we start with, is the very heavy oils that are used for large ships and power plants, along with other industrial applications e.g. manufacture of products such as plastics, pharmaceuticals, nylon, asphalt, etc.


The refining process is dramatically different today.  Demand for these light distillate products has increased rapidly, forcing the refiners to find new ways to extract more of them from the crude oil.  Catalytic, or chemical cracking now allows the refiner to make more of the valuable lighter distillates from each barrel of crude, leaving only about 16% of the residual as heavy fuel oils. Environmental concerns have resulted in additional treatment of diesel, for example to lower sulphur content. This also contributes to instability of today's fuels.


Diesel fuel refined with these new methods is far less stable than that made with simple distillation. This results in more rapid deterioration in the form of solids precipitating to make sludge.  Key fuel components such as paraffins and asphaltenes begin to oxidize and re-polymerize resulting in dark coloration, clogged filters and tank sludge that is commonly called "algae".  In reality, this stuff is actually wax and asphalt !! 


When this condition is present, the fuel does not combust rapidly causing a loss of engine efficiency. When the exhaust ports open, still smoldering fuel clusters become smoke & soot, leaving carbon buildup in the engine and exhaust trunk. Eventually, when it precipitates to the bottom of the tank, or is trapped in your filter, these key components cannot contribute to transferring the energy in the fuel to power the engine.

So the cause of the so called "algae" is simply the result of ageing fuel, which can occur in as little as 60-90 days, and depending on the cleanliness, and maintenance of the tanks in which it is kept, possibly even sooner.


The results of using fuel in this condition include:

  1. Tank Sludge that must be removed manually or dissolved with chemicals
  2. Clogged filters that must be replaced(and disposed of)
  3. Incomplete combustion
    1. Wasted BTU's
    2. Smoking engines
    3. Carbon Deposits in the engine
      i. Shortening the life of major (read expensive) engine components
      ii. Dirty engine Oil
      iii. Poor engine performance

Solutions for Recovering Diesel Fuel Quality

Traditional technologies used to protect engines from poor quality fuel include filtration to remove particulate e.g. dirt & sludge, separation of water content, and use of biocides to control microbial activity, which can contribute to more rapid formation of solids. Equipment to provide this protection is of course, still necessary.  However, what many operators are seeing is a much shorter life of the filter elements, resulting in more frequent filter changes.  This is due to the paraffins and asphaltenes (and other fuel components) having re-polymerized, or agglomerated to form solids.  This will happen even without the presence of microbes, so biocides cannot prevent this problem from occurring.



Today's Diesel Fuel is refined in a much different way than that of 15-20 years ago. Catalytic cracking produces a far greater volume of light & middle distillate products from each barrel of crude oil, however the stability of the fuels has been dramatically shortened.


Key fuel components such as paraffins and asphaltenes begin to form clusters that precipitate into the sludge commonly known as "algae". They comprise the bulk of this material that clogs filters, causes engines to smoke and perform poorly, and makes tank sludge.


ALGAE-X stops and reverses this process by impacting these clusters of molecules with inductive energy. This breaks up the clusters that have formed resulting in better filterability and combustibility of the fuel, and preventing the formation of tank sludge by the return line, which delivers clean treated fuel back to the tanks.

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