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EMDFA 401 is a multifunctional additive to improve the quality of heavy fuel oil when used in engine applications. The product has been conceived and formulated to address live problems experienced by users of heavy fuel oil on slow speed or medium speed engines.
In 2003 CIMAC India conducted a user survey to identify quality problems engine users of heavy fuel oil experienced. The findings of this survey have played a major part in the design and formulation of EMDFA 401.
The CIMAC survey highlighted the following primary quality issues.
  • Sludge formation was a problem widely reported by users. Typically 1% of the fuel was lost as sludge. Sludge not only implies loss of useful hydrocarbon energy but also results in operating irritants such as filter choking.
  • Formation of deposits in the fuel injection systems particularly the injector nozzles. Deposits on the injectors compromise the atomization of the fuel injection. Poor atomization results in delayed ignition and, consequently, incomplete combustion. This, in turn, causes a loss of fuel efficiency. Deposits in the fuel injection system also occasionally cause operational problems like rack jamming. Rack jamming necessitates engine shutdown and restart.
  • Excessive deposits on post combustion engine components such as exhaust valves and turbochargers. Such deposits are clearly the result of incomplete fuel combustion.

EMDFA 401 contains components to specifically mitigate the problems highlighted. The components are as follows:
  • Dispersant in EMDFA 401 ensures that the asphaltenes in the fuel remain in dispersion. Sludge is formed when asphaltenes conglomerate. By keeping the asphaltenes in dispersion the tendency for sludge formation is significantly lessened. Typically additive treatment will reduce sludge by a factor of 50%.
  • EMDFA 401 contains a detergent whose function is to chemically clean injectors. Sustained additive use ensures that cleanliness is sustained. Clean injectors assure optimum atomization and, therefore, improved combustion.
  • EMDFA 401 also contains a cetane improver to help improve the self ignition quality of fuel. The cetane improver helps in assuring more complete combust

Sustained use of the multifunctional additive EMDFA 401 provided the engine user several meaningful benefits. These include:
  • Improved engine efficiency, typically by a factor of 2% to 2.5%.
  • Reduced sludge formation by a factor of approximately 50%. In typical engine operations fuel losses by way of sludge could be of the order of 1%. Sustained additive use will reduce this to 0.5% or less.
  • Significantly lower maintenance costs. Use of the additive has helped in increasing run periods between overhauls. The longevity of components such as injectors, exhaust valve and turbochargers is also enhanced.
  • Elimination of operating irritants such as rack jamming and filter choking.
  • Reduced emissions.
  • Reduced engine noise.

The cost of using EMDFA 401 is of the order of 0.6% of fuel cost. The benefits from sludge reduction and efficiency improvement are, typically, 3% of fuel cost.  Thus the net benefit to a user is 2.4% of fuel cost.
Typically a 2.5 MW engine running at a load of 80% will consume 500 litres of fuel per hour. Assuming 350 days operation per year and an average heavy fuel oil cost of Rs 30 per litre the annual fuel bill is Rs 126 million per year. Use of EMDFA 401 can provide net savings through efficiency improvement and sludge reduction of Rs 3 million per year. In addition to these there will be substantial reductions in maintenance costs and the advantage of smoother, hassle free operations.
The recommended dosage of the EMDFA 401additive is 400 ppm or 1 litre of additive for 2500 litres fuel.
However for initial use we recommend a dosage of 1000 ppm or 1 litre additive for 1000 litres fuel for a period of 250 hours. This higher dosage is to accelerate the injector clean up process. At the end of this clean up phase the injectors would be free of deposits and the full benefit of additive use will accrue. Continued use of the additive at the normal dosage (400 ppm) will ensure that injector cleanliness will sustain.
The specifications of furnace oil are substantially less stringent than those for petrol or diesel. Consequently a user may receive fuel with substantial quality variations, while still being within the limits of the loose standard. These variations can have considerable effect on engine performance.
One important quality parameter that often varies is the self ignition quality of the fuel. In diesel the self ignition parameter is measured by what is referred to as the cetane number and the minimum cetane number acceptable is included in the fuel specifications. With heavy fuel there is no standardized test for cetane number measurement and therefore no specified parameter for assessing self ignition quality.
A parameter that is often used to assess the self ignition quality of heavy residual fuel is the Calculated Carbon Aromaticity Index (CCAI). The CCAI of a fuel is computed based on its density and viscosity. The formula for CCAI is as follows:
CCAI = D – 140.7log log (v+0.85) – 80.6 -483 log((t+273)/273)
Where, D = Density of fuel in kg per m3  at 15ºC
v = Viscosity of fuel in cst
t = Temperature in °C at which the viscosity is measured
The lower the CCAI the better the fuel’s self ignition quality.
An assessment of the fuel’s self ignition quality can be made as follows:
   790 to 830    Excellent to good
   830 to 850    Good to acceptable
   850 to 870    Acceptable to poor
   > 870    Poor
As an example compare the following two fuels.
Fuel 1 density = 962.5 kg/m3 at 15ºC and viscosity 152 cst at 50ºC
Fuel 2 density = 987.6 kg/m3 at 15ºC and viscosity 172 cst at 50ºC
Fuel 1 has a CCAI of 834 while Fuel 2 has a CCAI of 858. From a self ignition standpoint Fuel 1 is significantly superior to Fuel 2. Yet both fuels are within the specifications for heavy fuel oil for engine use.
The cetane improver present in the additive EMDFA 401 will compensate, to a considerable extent, the poor self ignition quality of the raw fuel. However after a certain stage it may be necessary to increase dosage of EMDFA 401 or supplement EMDFA 401 with a cetane improver. Generally speaking such situations arise when CCAI of the fuel exceeds 850 and deterioration of engine performance is discernible. EMDFA 401 dosage may be enhanced from 400 ppm to 600 ppm or in addition to 400 ppm EMDFA 401, 400 ppm cetane improver may be added.
A number of heavy fuel users have derived significant benefits through sustained use of EMDFA 401 for engine applications. Some of these users, the engine types operated and the benefits reported are:
Shah Alloys, Ahmedabad
  • 6 X 9000 BHP, Pielstick
  • 1 X 10500 BHP Pielstick
  • 1 X 10500 BHP Sulzer
Efficiency improvement by a factor of 2%
Significant improvement in maintainability
  • Reduced deposits on injectors, piston crown, exhaust valves and turbochargers
  • Enhancement of engine operating cycle between overhauls from the previously established norm of 8000 hours to 12000 hour
Asahi Glass India, Bawal, Haryana
  • 2 X 3.6 MW, B & W MAN
  • 1 X 1.9 MW, B & W MAN
Efficiency improvement of over 2%
Elimination of rack jamming problem on start up
Better than expected engine condition when engine was dismantled for overhaul
YKK (India) Private Ltd., Bawal, Haryana
  • 1 X 2.54 MW Wartsila W6L32
Efficiency improvement by 1.8%
Reduced sludge
Improved maintainability
Better than expected condition of injectors, exhaust valves, valve seats, combustion chamber components when engine was dismantled for overhaul
Reduced emissions particularly on start up
Healthier engine sound
Elimination of rack jamming problem
Shamken Spinners Limited, Kosikalan, UP
  • 1 X 2700 KVA Caterpillar
Problem of rack jamming was very severe causing unscheduled engine shutdowns and consequent loss of factory      production. Additivation almost completely eliminated the rack jamming problem.
Efficiency improvement of 1.35%
Pasupati Fabrics Limited, Kosikalan, UP
  • 3 X 2700 KVA Caterpillar
Efficiency improvement by 2.2%
Reduced sludge by a factor of 26% to 40%
Enhanced injector life
Reduced deposits on exhaust valves and turbochargers
Cleaner emissions VARUN BEVERAGES, Kosikalan, UP
  • 1 X 2.1 MW, Hyundai
A trial of EMDFA 401 was concluded in March, 2010 in which efficiency improvement of over 5% was achieved
Customer has commenced regular additive use