SFA International

Specialty Fuel Additives for Hydrocarbon Fuels

Diesel Engine Products

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, tug boats and pipeline pumps. High-speed engines are used in trucks and automobiles as well as agriculture and construction equipment.

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 compared with combustion turbines operated on similar fuels.

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.

Fuel Borne Catalysts

FuelSpec® 110 Series fuel borne combustion catalysts effectively reduce smoke (carbon particles) and NOx in Diesel engine exhausts and reduce fuel consumption.  We have measured up to 90% reduction in particulate matter in exhausts and 75% reduction in NOx.  Reductions in fuel consumption depend on engine design and sulfur content in the fuel and can range from 2% to 14%.  These products are currently available for off-road use in the United States.

FuelSpec® 113 and 114 product lines are EPA registered for on-road use in the United States.  FuelSpec® 113 is designed for fuels containing >1,000 ppm sulfur. 

FuelSpec® 114 is designed for fuels containing <1,000 ppm sulfur that require a lubricity agent to replace the lubrication properties removed in the hydrodesulfurization process.  FuelSpec® 114 is EPA registered for on-road use in the United States.

SFA's FuelSpec® 116, 117 and 119 Series are oil-soluble liquid organo-metallic catalysts based on SFA's patented iron - magnesium technology. 

FuelSpec® 116 Series catalysts are designed for use in fuels containing >1,000 ppm sulfur.

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FuelSpec® 117 Series catalysts are designed for use in fuel with <1,000 ppm sulfur.  Removal of sulfur by hydrodesulfurization in the refining process results in reduced lubricating properties of the fuel.  Our FuelSpec® 117 Series catalysts include a lubricity agent to compensate for this loss in lubricating property.

FuelSpec® 119 Series catalysts are designed for use in large, low-speed engines operating on heavy fuel oil (HFO) or residual oil (RO).

Product Testing and EPA Registration

These products have been extensively tested by government and private research laboratories, including Automotive Research Association of India, Southwest Research Institute in San Antonio, TX, University of Houston and Jerry Lang Combustion Consultants in Lindale, TX.  These results are presented in papers in the SFA Technical Article & Paper Library and on the Support page.

Details concerning EPA Registration of SFA products can be found on the "Support" page.

Catalyst Mechanism

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

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Clean engine

Engine 20 Treated - Close up, note absence of deposits and corrosion.

Clean engine valve seats.

Engine 20 Treated - Cylinder head. Note clean valve seats. Intake on left, exhaust on right.

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.  The pictures below show a piston crown and cylinder head for a Wärtsilä V32 18-cylinder 6 MW engine used in electricity generation.  This engine operates on water-washed residual oil containing 300 ppm vanadium and percent levels of sulfur.  These pictures taken after several 1,000 hours operation show excellent control of deposits and corrosion.  The dark spots on the piston crown and head are liquid fuel.

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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