Diesel Engine Fuel Treatment

There are three basic types of Diesel engines: low speed (150 – 450 rpm), medium speed (450 – 1,000 rpm) and high speed (> 1,000 rpm). Low speed engines are commonly used on ships and for generation of electricity. Medium speed engines are used for a wide range of purposes including generation of electricity, railroads and pipeline pumps. High-speed engines are used in transportation.

Low speed engines have been used for many years with low quality fuels ranging from vacuum distillates to residual oils. The poorest quality fuels contain 300 or more ppm vanadium, high levels of sodium and 3-4% sulfur. Because of relatively low temperatures in the engine, deposits and corrosion on piston crowns and exhaust valves are minimized.

In recent years, considerable interest has developed in running medium speed engines on residual oils. Because of higher operating temperatures, piston crown and exhaust valve deposits and corrosion are a significant problem. There are also problems with deposits and corrosion on turbocharger blades.

Another problem with Diesel engines is emissions. These include smoke (unburned carbon particles), nitrogen oxides and sulfur oxides.

Additives for modification of deposits and inhibition of corrosion

Historically, low speed Diesel engines have used fuel additives based on silicone compounds. FuelSpec® 100 Series silicone compounds combine with vanadium and sodium contaminants to form soft, friable deposits at the operating temperatures of the low speed engine. SFA offers products compatible with low speed engine operation.

Medium and high speed engines represent a different problem. Higher temperatures result in operating problems more like those found in combustion turbines operating under derated conditions. Severe deposit build up occurs on the piston crown and exhaust valve leading to corrosion. In extreme cases, corrosion leads to metal failure of the piston crown with exhaust gasses and flame entering the crankcase. Failure of the exhaust valve leads to loss of compression and failure of the cylinder to produce power.

In this case, SFA's FuelSpec® 130 Series oil soluble magnesium products will control deposits and corrosion. The magnesium to vanadium plus sodium ratio is less than the 3/1 treating rate used in combustion turbines. The actual treating ratio depends on a number of factors including power, derating factor, speed of the engine and fuel characteristics. An on-site survey of the engine is generally required to develop the best treating condition.

SFA products tested in field conditions have yielded excellent control of corrosion and deposits. The problem has been almost completely eliminated under proper treatment conditions.

Fuel Borne Catalysts

FuelSpec® 110 Series fuel borne combustion catalysts effectively reduce smoke and carbon particles in Diesel engine exhaust. Engineering modifications have reduced particulate matter and unburned hydrocarbons from the exhaust of high-speed engines. Medium and low speed engines continue to be a problem for exhaust emissions. These products are currently available for off-road use in the United States.

As discussed in the technical papers available through this website, SFA has developed a patented combustion catalyst technology that reduces Diesel exhaust emissions by up to 90% and yields fuel efficiency improvement commensurate with reduction of particulate matter and unburned hydrocarbons in the exhaust. These are our FuelSpec® 116 Series combustion catalysts. We have seen a range of fuel efficiency improvement from 2% to 20% depending on the condition of the engine and fuel characteristics. This new technology is based on a patented and tested iron - magnesium synergistic mixture.

FuelSpec® 116 series fuel borne combustion catalysts aid in the removal of trapped particulate matter from exhaust system filters.  The catalyst releases energy and ignites carbon material resulting in a continuous removal of particulate matter trapped in the filter.  The result is longer periods between maintenance and cleaning the filter.

These products have been extensively tested by government and private research laboratories, including Automotive Research Association of India and Transportation Research Laboratory in Great Britain. Further testing is planned in the United States utilizing the TCEQ grant recently received by SFA. We expect this to lead to EPA registration and approval for on-road use in the United States by the end of 2005.

Catalyst Mechanism

For more information on the mechanism of this process, go to the SFA Technical Article & Paper Library.

Technical Service

SFA Engineers provide technical service to aid customers in achieving optimum results from use of Diesel engine additives. Before a recommendation is made, a survey of the plant is made. From this information, a proposal is prepared outlining the additive application, dosage rate, function and expected benefits.

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