The term Fuel Polishing comes from the process of taking old, degraded fuel that has become brown or sometimes black in appearance and making it clear and bright and restoring its quality.

Crude oil contains hundreds of different types of hydrocarbons all mixed together.  The refining process separates these hydrocarbons for use in various products and purposes.  Some of the heaviest components are the asphalts found in crude oil.  This is the same product that is used to pave highways.  In the refining process, some of these asphalts, commonly referred to as asphaltenes, ends up in diesel fuel products.  These asphaltenes don’t usually hurt anything and are small enough, in the 2 micron range, to easily pass through most fuel filters and get burned in the combustion chamber of your engine without problem.  Because they are in solution shortly after the refining process, their presence in the diesel fuel is not obvious.  But when fuel is in storage for a period approaching a year from when it leaves the refinery (six months for bio-fuels), these asphaltenes agglomerate (combine with each other to form a larger mass).  As these clumps grow in size (they can form clumps of 200 microns and larger), they make the fuel appear dark and these clumps often will clog your fuel filter.

Fuel Polishing is the process of passing the fuel through a Fuel Conditioner (see the FAQ Section below for how a Fuel Conditioner works) that will break apart the agglomerated asphaltenes, reducing the clumps to a size where they are returned into solution and the fuel again becomes clear and bright, hence the term “Fuel Polishing”.

Many enterprising individuals and companies market fuel polishing services that utilize a fuel pump, one or more fuel filters (or sometimes some novel filtering media such as paper towels or some other “proprietary” means of removing solids from the fuel), and top it off with a heavy dose of chemical biocides.  They make a case for combining the use of strong chemicals with the filtration process, but the fuel does not return to the clear and bright appearance as expected. Also, the fuel does not regain the optimal fuel quality that is expected, and the fuel does not deliver smoke-free combustion nor extend the time between filter changes as promised.

Without a Fuel Conditioner (see “How Does Fuel Polishing Improve Diesel Fuel?” below) that will return the fuel to that clear and bright condition, all you are doing is filtering the fuel.  The Fuel Conditioner also is the principal component that rids your fuel of microbial and fungal contamination without the need for biocides or other hard-to-handle chemicals.

Biocides introduce a whole new problem to the situation.  The chemicals are quickly diluted and do not achieve total destruction of the microbial and fungal infestation.  This growth is contained in the heaving tank bottom sludge and debris.  The chemicals cannot penetrate this material and residual microbial growth lingers and quickly begins the reproduction process and, within a few months, the problem of clogged filters is back.

In addition, having this chemical now in the tank bottom water results in this water requiring special handling, just like the biocide containers, in accordance with governmental regulations and mandates.

Frequent Filter changes and incurring the expense and inconvenience of cleaning fuel tanks have become acceptable periodic maintenance instead of a warning signal for engine failure. Filter elements should last a thousand hours or more, and injectors some 15,000 hours. However, since diesel fuel is inherently unstable, solids begin to form and the accumulating tank sludge will eventually clog your filters, ruin your injectors and cause engines to smoke. 

Fuels and oils are susceptible to natural deterioration, like any other organic fluid. Oxidation, chemical incompatibility, water, and microbial infestation all contribute to the process of polymerization and stratification of diesel fuel and other hydrocarbons. This results in poor Fuel Quality, and the formation of sludge, bio film and acids in the fuel tank.

These by-products of the fuel breakdown process cause clogged filters, corroded injectors, pumps and tanks, incomplete fuel combustion (as evident from black smoke, caused by un-burned fuel, coming from the exhaust), carbon build-up on internal engine components, and the loss of power. As these problems build on each other, these individual symptoms of bad fuel ultimately lead to complete engine failure.

All major diesel engine manufacturers have set minimum fuel standards for the diesel fuel to be used in their engines, and failing to maintain the fuel that you use in a manner so that it meets those standards could lead to engine component failures and denied warranty claims.

As an example, Caterpillar has published “Cat Commercial Diesel Engine Fluids Recommendations” (SEBU6251-17 September 2014 [a more recent version may be available]) that states “In order to meet expected fuel system component life, 4 micron(c) absolute or less secondary fuel filtration is required for all Cat diesel engines that are equipped with common-rail fuel systems.” (Page 34) You should not assume that fuel being delivered to you meets the manufacturers requirements, and certainly fuel that has been in your storage tank for an extended period of time may not meet requirements of diesel engine manufacturers. Additional cleanliness standards apply to diesel fuel. Caterpillar recommends that the fuel dispensed into the machine tank meets “ISO 18/16/13 cleanliness level.” (Page 49)  You can learn more about Fuel Cleanliness Standards at this link.

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Diesel engines continuously return fuel not used for combustion back to the tank. The repeated exposure to the heat and pressure of the injection system accelerates this breakdown of fuel quality. Fuel quality and fuel chemistry is affected by transportation, storage tank conditions (as well as length of time in storage), and factors such as oxidation, water in the fuel, microbial contamination (contributing to acid formation), and incompatibility of fuel additive packages with after-market additives, etc.

This toxic combination negatively impacts: (i) the filterability of the fuel through filters that become clogged; and (ii) causes a dramatic increase in the size of the fuel droplets emitted from the fuel injector into the combustion chamber. The degraded condition of the fuel, when combined with the injector degradation that occurs over time from the use of the degraded fuel, result in fuel not being completely burned in the combustion chamber causing the formation of carbon deposits on internal engine components, all evidenced by a noticeable increase in smoke from the exhaust, loss of power, and an increase in fuel consumption.

Modern High Pressure Common Rail (HPCR) Fuel Injection, common on engines placed in service since 2007, has been the cornerstone for advances in combustion efficiency and enables a diesel engine to achieve the stringent emissions levels now mandated. 

The design of this system is such that a constant fuel pressure is available at the injector 100% of the time during engine operation thus providing a higher available mean time injection pressure over the older Electronic Unit Injector (EUI) designs.

This feature ensures that fuel droplets are atomized the moment they leave the injector nozzle. As EUI systems had to develop the fuel pressure during the injection event, they have a tendency to form larger droplets at the start and end of each injection event.  HPCR injection systems are also able to regulate fuel injection pressure based on engine requirements, speed, and duty using the engine ECU combined with the fuel pump.

The high pressure created in these injector systems (which can exceed 30,000 psi) and the smaller tolerances in the injectors require more attention to fuel cleanliness and fuel quality, and have resulted in engine manufacturers requiring a 4-micron final fuel filter to protect this fuel system.

But these clumps of non-fuel create significant problems, including:

• excess exhaust smoke

• loss of power

• higher maintenance costs

• shorter injector life

Poor quality or contaminated diesel fuel now contributes to more than 80% of fuel system related failures in modern diesel engines.

Diesel engines continuously return fuel not used for combustion back to the tank. The repeated exposure of the fuel to the heat and pressure of the injection system accelerates the breakdown of the diesel fuel and compromises the fuel quality. Fuel quality and fuel chemistry is affected by transportation, storage tank conditions (as well as length of time in storage), and factors such as oxidation, water in the fuel, microbial contamination (contributing to acid formation), and incompatibility of fuel additive packages with after-market additives, etc.

This toxic combination negatively impacts: (i) the filterability of the fuel through filters that become clogged; and (ii) contamination and corrosion of the injectors, causing a dramatic increase in the size of the fuel droplets emitted from the fuel injector into the combustion chamber.  The degraded condition of the fuel, when combined with the injector degradation that occurs over time from the use of the degraded fuel, result in fuel not being completely burned in the combustion chamber causing the formation of carbon deposits on internal engine components, all evidenced by a noticeable increase in smoke from the exhaust, loss of power, and an increase in fuel consumption.

By periodically using the TK-240 XT Fuel Polishing and Tank Cleaning System to maintain clean, clear and bright fuel uncompromised by water and microbial contamination, engine performance is maintained, more economical operation is assured, and engines will last longer.

The LG-X Series Fuel Conditioner is the most important component of the TK-240 XT Fuel Polishing and Tank Cleaning System.  Without the Fuel Conditioner, all you would be doing is filtering fuel, and that is not Fuel Polishing!

Operating on the principle of induction on the process of combining kinetic and magnetic energy to influence the behavior of electrons, the LG-X Series Fuel Conditioner provides a powerful magnetic field and the flow of fuel provides the kinetic energy (think about how a generator produces electric power by spinning in a magnetic field).

The asphaltene component of fuel that has come out of solution and makes the fuel appear dark is still there after the fuel polishing  process is performed, but like the fuel when it left the refiner, the Fuel Conditioner causes the asphaltene component to go back to being in solution and you again have clear and bright fuel.  Microbial contamination, having passed through this magnetic field repeatedly, has been impacted and its reproduction process is compromised. You cannot say these “bugs” are dead (they are still present), but they remain inert for months while the fuel is used and periodic re-circulation of the diesel fuel assures that their presence does not grow.  This infestation will in time pass through the combustion chamber and be gone.

As the Fuel Conditioner does not filter the fuel, but treats it as it passes through the unit, there is seldom any reason to suspect that a restriction exists in the LG-X Series Fuel Conditioner. However, there are situations where the benefit of circulating your fuel through a magnetic unit has added benefit.

Should the LG-X Series Fuel Conditioner be used in a situation where it is installed in-line on the fuel line between the fuel tank and the engine, the Fuel Conditioner can provide continuous Fuel Polishing, but also provide added protection to your engine.

If a fuel tank itself is in poor condition, where the tank may be rusted on the inside and rust flakes may be coming loose, or an upstream storage tank was old and rusted, the LG-X Series Fuel Conditioner would prevent the sharp metal flakes from progressing to the fuel filter where they may pierce the filter medium and allow unfiltered fuel to proceed to the fuel system to create havoc on your injectors.  Also, should the source of your fuel be questionable, such as a marine vessel that fuels at island fuel stops with little oversight, or remote mining operations where a supplier may not be reliable, having the LG-X Series Fuel Conditioner installed on each item of equipment to stop metal shavings or other ferrous debris that may be the result of lax maintenance on upstream distribution equipment could be a great benefit.

If a fuel blockage in the fuel system occurs, and the Fuel Conditioner is suspected to be the cause, simply remove the cover plate, carefully remove the magnet and wipe it clean with a shop rag.  Carefully replace the magnet and re-attach the face plate. A parts kit with replacement O-ring and attachment screws is available (call for more information).

The process of how the LG-X Series Fuel Conditioner makes clear, bright and more combustible fuel, as well as restoring degraded fuel and eliminating the effects of microbial contamination, is compelling.

It is critically important to re-circulate the fuel through the TK 240 XT Fuel Polishing and Tank Cleaning System.  But the re-circulation process alone does not create sufficient fuel flow and agitation in the tank during the tank cleaning process.  In most instances, there is not enough force created with the fuel flow being discharged back into the tank to really knock the slime and sludge off the sides and inside-top of the tank and stir up the years of accumulated sludge on the tank floor!

What you need is something to clean the tank and put this bio-film and slime into the fuel flow so that the TK-240 XT Fuel Polishing and Tank Cleaning System can filter out the debris, the Fuel Conditioner can get to the microbes, and the agglomerated asphaltene component of the fuel can be broken down and removed from the fuel stream.

Although moving the suction hose stinger (an extension to the hose, usually rigid, allowing for the control of the suction line intake end) of the Fuel Polishing System around the bottom during the fuel re-circulation phase does stir up considerable material for the suction line to deliver to the TK-240 XT Fuel Polishing System, there needs to be something that can dissolve the slime and organic material off the tank walls, top, and floor prior to and during the re-circulation process that will also keep working between Fuel Polishing Treatments.

It is recommended that the diesel fuel tank be treated with the AFC Series Broad Spectrum Additive Concentrate appropriate to your application a day or two prior to the first re-circulation. 

The AFC Series of Fuel Catalyst and Tank Cleaning Additives are available in three varieties.  The AFC-705 is for pre-2007 manufactured engines and includes in its chemical makeup a surfactant that helps in the removal of residual water from the fuel tank bottom.

The AFC-710 is available in both liquid and powdered form and is Tier-4 compliant meant for 2007 and newer engines.  This product lacks the surfactant and dispersant components to comply with Tier-4 requirements.   Otherwise, this product is an excellent fuel catalyst and tank cleaning additive.

AFC-805 is a cold weather fuel catalyst and tank cleaning additive for use in cold weather environments and is Tier-4 compliant meant for 2007 and newer engines.  It likewise effectively decontaminates and cleans an engine’s entire fuel and injection system and continues to work in cleaning storage tanks and stabilizing fuel for up to twelve months.

The AFC-Series additive that suits your needs should be added to a full tank of fuel (after any accumulated water is removed) or the tank filled just after the additive is introduced to the tank.

After completing the initial fuel polishing re-circulation, continue the use of AFC Series Additives at least once or twice every six months thereafter to continue the tank cleaning process continues for badly contaminated tanks.   This will enhance and accelerate the long term tank cleaning process, mainly the hardened sludge in the tank bottom, by breaking down and dissolving the existing tank sludge. 

For tanks that are not so badly contaminated, use of the AFC Series Additives periodically will assure the fuel tank remains clean and the fuel is stabilized.

Perform a Fuel Re-circulation every six months with the TK-240 XT Fuel Polishing System and Check the Tank Bottom for Water at Regular Intervals

Always check the fuel tank for an accumulation of water in the bottom of the tank prior to doing a re-circulation. Using a rod, sometimes used to measure fuel in a storage tank, or a length of 1/2 inch PVC pipe, spread a line of Kolor Kut Water Finding Paste on the side of the rod or pipe and insert to the bottom of the tank, allowing it to remain for several minutes. If the paste touches water, it will change colors, showing how much water is in the tank requiring removal prior to initiating the re-circulation process.

Add the AFC Series Fuel Additive to your fuel tank appropriate for your equipment.  Treating a full tank of fuel is important as you don’t want to clean just the bottom half of the tank.  You want the additive treated fuel to touch every part of the sides and, if possible, the top of the tank — anywhere the fuel touches during equipment operation.

The AFC Series Fuel Additives are industrial strength and concentrated for the focused dual-purpose of:

• First – working hand-in-hand with the TK-240 XT Fuel Polishing and Tank Cleaning System by cleaning the fuel tank in preparation for the periodic re-circulation and treatment of the fuel; and

• Second – as a continuing part of a Fuel Management Plan to maintain the cleanliness of storage tanks and fuel systems, and assuring that your fuel maintains Optimal Fuel Quality.  This is defined as fuel that is like it was when it left the refinery.  The TK-240 XT Fuel Polishing System, working with the AFC Series Tank Cleaning Additives, assure your fuel is of optimal quality for as long as you depend on the fuel to efficiently operate your equipment.

Removal of Residual Water

Prior to the initial and any subsequent fuel polishing re-circulation, pump any measurable accumulated water out of the tank for proper disposal. It is, however, often impossible to remove all of the water.  The AFC-705 Catalyst and Tank Cleaning Additive contains a surfactant that will emulsify this residual water up into the fuel for removal by a Water Block Filter on the TK-240 XT Fuel Polishing System.

The AFC-710 Catalyst and Tank Cleaning Additive, available in both liquid and powder form, and the AFC-805 Cold Weather additive, both of which is Tier 4 Compliant, does not include the surfactant component, but otherwise works the same as the AFC-705 to dissolve deposits and stabilize the fuel.  As an option to the liquid AFC-710, a powdered form of AFC-710 is also available. It is easier in certain instances to handle, store and transport.

Additive Dosage

Depending on the condition of the fuel and the amount of sludge build-up, it is recommended to initially use a double dose of one to twenty-five hundred (1:2500 – one oz. to 20 gallons of fuel) and circulate the capacity of the tank five times.  The use of AFC Fuel Catalyst & Tank Cleaning Additive has proven to be essential in accelerating the tank cleaning process. The AFC Series addivites contains corrosion inhibitors, lubricity enhancers and combustion catalyst.

For engines manufactured in 2007 and later, use AFC-710, available in both liquid and powdered form. AFC-710 and AFC-805 does not contain the dispersant and surfactant (used to emulsify residual water into the fuel for removal in the circulation process as does AFC-705), a component that does not allow for qualification as a Tier 4 product.

Tank Cleaning & Fuel Treatment for Cold Weather Use

For cold weather operations, AFC Fuel Catalyst AFC-805 is a unique and powerful anti-gelling broad-spectrum fuel additive specifically formulated for use in Diesel, Bio-fuels, Gasoline, Kerosene, and HFO.  AFC-805, also Tier 4 compliant, can be used as part of any preventative fuel maintenance program, and is ideal for use in bulk storage fuel tanks in cold weather environments.  AFC-805 enhances the breakdown and removal of sludge, slime, and bio-fouling from tank walls and baffles that are difficult to access.  It continues to work in storage tanks cleaning and stabilizing fuel for up to 12 months with a single dose.