AmFleet Diesel Fuel Info
 

DIESEL FUEL TECHNICAL INFORMATION SUPPLEMENT

This information is to explain the mechanisms and how and why chemicals work in commercially available diesel fuel and the benefits of using or not using chemicals.  As presented here, all benefits are stated from test data utilizing proven test methods and refinery fresh fuel.

Major benefits of AmFleet Chemicals:
 

We shall now approach the problems in the fuel market:

CETANE / COMBUSTIBILITY / QUALITY

The degree of combustibility is often looked at as interchangeable with fuel quality and sometimes measured utilizing the ‘cetane number’. This is a tested numerical number and alternative methods allow for mathematical calculation.  The inherent cetane number of the fuel is determined by the chemical blend of the distillation ranges of the components utilized in the make-up of the fuel at the refinery. It may also be beneficiated by the addition of chemicals from the octyl nitrate generic family of chemicals. Because these chemicals are expensive by nature, their use is minimized. They are very effective and can have substantial effects on an engine’s power and performance, fuel use  efficiency, ease of starting, dramatic elimination of carbon deposits, wasted unburned fuel, and exhaust pollutants.

Fuel quality, as generally looked at by the large user, takes into account mileage and fuel economy, the age and color of the fuel, particulates and sludge present, how well it burns on ignition, if ignition is complete, is water present, is bacteria and slime present, and does the fuel have enough lubricity to stop causing parts to wear out? It’s true all of these do contribute to fuel quality.

For the sake of this paper we will break all of these segments down into their individual units.  We do this because all of these elements have to be treated differently, with different chemicals, even as they are inter-related.

Using this standard, the octyl nitrate family of chemicals are generally regarded as the only method to make the fuel better burning, post-refining. Adding these chemicals to the fuels in the 300 parts per million to 1000 parts per million range can have dramatic effects on complete fuel burning, (the horsepower derived, mileage and degree of combustibility) the corresponding decrease in pollution  (nitrous oxides, carbon monoxide, carbon and residual visual particulates, and unburned hydrocarbons) and a big decrease in wasted fuel.

There are various members of the octyl nitrate family, depending where the nitrogen molecules and how many are attached on the chain link. The performance of the resultant chemicals in fuels can vary substantially.

Another phenomena that we have observed is that it takes a certain treating rate before any benefit shows up in the fuel. Adding a small amount will show no detectable benefit. Once a working threshold has been reached, by adding additional chemical, the benefits will gradually increase until a plateau has been reached.

When adding chemical to reach the plateau level the benefits may increase very rapidly or they may increase slowly. How the cetane number increases, rapidly or slowly, differs with nearly every fuel. We have seen correlations from crude sources, refining methods, types of storage, and different transportation techniques.  Once a treated fuel has reached the plateau level additional benefits will cease to be apparent or be too expensive for further exploration.  Generally the initial threshold for treating is about 225-250 parts per million and the plateau phenomena starts showing up at about 550-650 parts per million.  This is the treating rate of the octyl nitrate family of chemicals only, not for the total additive package. Poorer grade levels of fuel have a definite tendency to show more and quicker responses and benefits.

FUEL STABILITY [Color - Particulate - Gum - Sludge - Oxidation]

These factors come into play the moment the fuel is refined. Fuel begins to age immediately if it is not treated promptly. There is no reversal, other than re-refining. It is for this reason that the fuel should be treated as soon as possible.  Treating can at least Stop the aging process.

The stability problem in fuel is time and temperature dependent. The more time and exposure to oxygen and degrading elements, the greater the degree of effect. The higher the temperature, the greater the degree of effect. Temperate zone stored fuels are much more susceptible.

Another factor in degradation is the presence of metals in the fuel. They are a carry-through from the crude source not captured during the refining. Some refiners add metal deactivators and some do not. All of Refinery Research Corporation’s fuel additives have substantial amounts of metal deactivators incorporated within formulation. The disadvantages of untreated metals and compounds are obvious and can be profoundly damaging.

When fuel starts to become unstable it usually becomes darker. This will not necessarily affect the fuels’ value. As this progresses the fuel will chemically change and form particulates and sludge byproducts. This causes all kind of problems, from varnish formations, plugging of injectors, filter contamination and stoppage, it acts as a host to fungi and bacterial formation, attributes to corrosion throughout the fuel system, and resultantly affects the flash point of the fuel. It also passes these contaminates all the way through the combustion process, adding to pollution.

Refinery Research Corporation’s fuel stability additives are extremely effective. The A.S.T.M.  D-2274 test we use in determining the efficacy in diesel fuel is also used for aircraft turbine/jet fuel and one of the standards for military specification approval. It is an accelerated test to reflect degradation and approval for fuels aged under ambient conditions over a two (2) year period of time under normal storage conditions.

CORROSION & CORROSION INHIBITORS

It is a common belief by many commercial fuel users that this is not a problem with them because they use the fuel so fast they never have a corrosion problem. This is completely false. Many users probably don’t recognize this in their maintenance program when they overhaul their injectors and replace their fuel system pumps or have excessive ring wear and cylinder wall scoring.

Corrosion takes many forms. It can be attributed to metals and salts left in the fuel from the refining process, contaminates introduced post refining, the introduction of contaminates by the fuel transportation process to the dealer or user, oxygen content of the fuel, degradation byproducts of the fuel, fuel stream components such as the aromatic content, water through transportation, and introduced organics such as bacteria and fungi. It can also be introduced through airborne methods as condensation (fresh water & salt air) and airborne mold and fungi spores.

Refinery Research Corporation uses three methods of fighting corrosion in fuel systems. One group of chemicals treats for the oxygenates and corrosive elements in the hydrocarbon phase. This is generally referred to as the primary phase or the antioxidant phase.

The second group treats for corrosion in the water phase. Many users don’t realize there is always water present in diesel fuel. A good portion of it is carryover from the refining process. It is present in both soluble and insoluble forms. It can be a leftover from the desalting process. It is introduced through transportation. Generally people attribute it to condensation (usually a very small percentage), but usually they buy it with the fuel.

The third group treats for the free and chelated metals group. They can be very corrosive causing extensive damage to both the efficiency of the fuel and to equipment.

The corrosion phase of fuel treatment is usually very much underrated. It’s relatively inexpensive to treat and can greatly decrease maintenance costs. The resultant damage from the corrosive elements and damage to the fuel system can substantially increase pollution.

WATER (and Treatment or Elimination)

Water is always present in diesel fuel. Always! It does not burn and cannot be made to burn. It cannot be changed to be harmless. It cannot be encapsulated. It is in different forms; soluble and insoluble, fresh and containing salts. It contains oxygen and is corrosive. It atomizes differently from fuel and cools the fuel. It is a host to fungi and bacteria. It freezes easily. It can be very expensive.

When and if water gets through the coalescers and filters it is injected with the fuel into the cylinders. It atomizes at a different rate than the fuel and the fuel atoms that are in contact with the water atoms are cooled. This phenomena usually occurs heaviest near the point of injection, and derives the term ‘cellular cooling’. When the cylinder reaches a certain temperature the drier fuel will ignite. The cooler fuel will not. This will cause uneven burning throughout the cylinder, and thus residual formations and unburned fuel.

Unburned fuel and partially ignited fuel are some of the greatest causes of visible pollution. This is also one of the major causes for loss of horsepower and a decrease in mileage or loss of miles per gallon.

TWO Ways to Handle Water

DISPERSE IT
Recommendation - DON’T

This is very old technology. It is the least expensive way and is still used by a lot of additive manufacturers selling to the retail marketplace but never in and to the refining industry. What it does is suspend the water throughout the fuel (along with all other dirt, particulate, and other contaminates) and try to drive them through the filters, through the coalescers, through the injectors, and into the combustion chamber, and out the exhaust ports, to get rid of it.

Dispersants do this to a good degree. They also tend to be hydrophilic (attract water from all sources, even air), have very low flash points - thus lowering the flash point of the fuel and destroying the B.T.U. value of the fuel; and try to drive the water and other contaminates straight through the coalescers and filters, thus destroying their function and sometimes their elements and mechanics.

Refiners put demulsifiers into the fuel stream at many stages during the refining process to eliminate water and also into the finished fuel. When you add a dispersant this nullifies the activity of these chemicals. You are trying to do opposite things at the same time.

With dispersants you still have all of the problems with water and the user is destroying equipment at the same time. Water in its various forms is probably the most expensive factor for the fuel user; in equipment and higher fuel costs.

ELIMINATE IT - DEMULSIFY & FILTER IT
Get it Out of the Fuel Stream

This is the method we use. It works with the coalescers and filters, does not add more contaminates to the fuel stream, and works in conjunction with the refiners intent, and stops water from getting to the engine.

If extreme gross amounts of water are present it will drop it out in the tanks before it even gets to the filters. This is important in that it will not plug your filters thus ceasing operations. Periodically drain your fuel tank bottoms and storage tank bottoms. This should be done periodically because of  the demulsifiers  the refiners put into the fuel before to handle previous water problems.

With normal and minimal amounts of water our chemicals will help the coalescers and filters draw off this and other contaminates, as they are designed to do. They work with the demulsifiers that the refiners put into their fuel (only much stronger), for that same purpose.

Remember - Water will not disappear. And more importantly, you get some with every tank of fuel you buy. It’s always there. If you keep running it through your engine, sooner or later it will do damage. The water will not evaporate and neither will the mechanical problems associated with it.

FUEL INJECTOR CLEANERS

There are two (2) basic types of fuel injector cleaners. The first is the dispersant (or sometimes referred to as the soap method) working on the emulsification method, not dissimilar to how dish soap works with water in cleaning dishes in a sink.

This method tries to suspend all particulate into the main fuel stream, from the storage tank all the way through the fuel system and out the exhaust. This means all contaminates, even water. They also tend to be film formers (remember soap scum). This film tends to trap and hold foreign matter causing a build-up and stoppage.

When you use this type of injector cleaner you will initially have a cleaning action, which is desirable. But you have to use it constantly or the film surface will build up and this will cause injector plugging.

The second, and recommended type, is the ion exchange method. These work on the premise of destroying the electrical attractiveness of the particulate or contaminate to the retaining wall. It ‘sheds’ the contaminate. They are not film formers. They are usually very fast working and effective, though expensive. In very high concentrations they will polish injectors like new.  Care must be taken to have an adequate lubrication package built into the formulation where a high concentration of these cleaners are used. It is very apparent in some packages designed for and sold into the retail market that the companies do not build a lubrication package in with these cleaners and, therefore, have to limit the concentration of activity; to the extent as to be ineffectual. They are relying on extreme long term and continual usage to do the cleaning.

All packages manufactured by Refinery Research Corporation utilize these ion types of injector cleaners. We also put into these cleaner packages lubricants to counteract and replenish this cleaning ion exchange physical action. Additionally a special lubrication package is added to enhance the attributes of low sulfur and reformulated diesel fuel.

SLUDGE - PARTICULATE - BACTERIA

Sludge is a function and defined as a refining byproduct. It is an all-inclusive term to cover everything in fuel, except water, which is not supposed to be there. This can entail everything from dirt, decomposed hydrocarbons, to other decomposed and living organic material such as bacteria and fungi spores.

Particulate is generally to mean carbon particles that are the result of the fuel decomposition due to an unstabilized fuel condition and oxidation.

Bacteria and fungi can be introduced into the fuel stream anywhere from the refinery to the end user. They can be introduced through spores in the atmosphere being allowed to come into contact with the fuel or fuel tanks. Most often they are introduced when fuel comes into contact with previously contaminated tanks.

1. Stabilize the fuel as soon as possible. This stops the formation of the particulate and the breakdown of the hydrocarbons. It stops the development of the composite parts that will form the varnishes later. Do this in the vehicle’s tanks or the storage tanks. Diesel engines are designed with a circulatory bypass system and this fuel is heated to some extent. It’s never to late; you just can’t reverse the aging that has already been done.

2. Eliminate as much of the water as soon as possible. Water is corrosive and holds and carries oxygen. It also holds corrosive salts that have been previously dissolved.

Water has one other very detrimental aspect. It acts as the host for bacteria and fungi. They cannot grow without it. These organics grow at the interface where the water molecule touches the fuel molecule. Take the water away and you’ve stopped a potential big problem.

3. Demulsify (drop out) these organics out of the fuel phase. They will go to the bottom of the tank, or if gross amounts are present the filters will start to catch them.

With small amounts of organics in the bottom of the tanks they will start to decompose and break up into their basic elements in an extremely small micron size. Remember you already have corrosion inhibitors present and with properly treated fuel with the proper additives these are relatively harmless.

If large amounts are present, much will go to the filters. It is better to change or drain a filter than to overhaul an engine and do an injector job. That is the purpose of the filter in the first place. Never use a dispersant in a system where these organics are present. It literally helps them grow by giving them more water/hydrocarbon interface to attach to. It will also try to drive them through the filters to clog the injectors and form carbon deposits in the engine.

4. Use a very active injector/valve cleaner. The organics are in all sizes and some will get through the filters. Also the filters may not catch all of the small micron size molecules that have broken down. They will be released very slowly; that is a good thing. The injector/valve cleaner can handle this matter easily during the normal course of operation.

LUBRICATION / LUBRICANTS

Use them; they are a must in the new fuels. Sulfur was a lubricant in the old fuels. Years ago it was specifically added to jet fuel in the form of a lubricant. When refiners removed sulfur from the fuel they also made the fuel drier with less lubricity. Now users must add special lubricants to compensate. Without it drive pumps and valve seats get damaged and destroyed. Our diesel fuel lubricants in our additive packages have been used in the new jet fuels for years. Increased lubricity is a must.

We use three (3) different lubricants in our systems. All are necessary.

Remember, these major benefits of AmFleet Chemicals: