Q & A > Question Details
Why must we maintain distillation of diesel 95% at 360 degrees centigrade for Euro-III ? If less or more what is the effect on engine performance?
26/03/2010 A: Balasubramanian Iyer, Nexen CNOOC Limited, balasubramanian.n@aol.in
As per my understanding, for the Diesel properties. this is one of the most important property as at 360 deg almost 95% should vapourize and only 5% should remain. As in diesel engine doesn't have a spark plug and the ignition inside the engine is caused only by the air and temperature increased inside the engine.. if the percent increases then more % of lighter ends are present and if the percent decreases then more heavier are present in the diesel cut. For proper combustion the diesel should vapourize and proper ignition mixture should be formed inside the engine so that there will be no lag or lead in combustion inside the engine. The added advantage of maintaining that parameter is as follows:
However, reduction of the 95% distillation point will have the following positive effects:
• Density reduction
• Most refractive sulphur components will be removed from the feedstock
• Concentration of heavy aromatics components will be reduced
• Improve the cold flow properties of the diesel
21/07/2009 A: Alan Goelzer, Jacobs Consultancy, alan.goelzer@jacobs.com
For Euro Diesel Gas Oil Fuels, both the density specification of 0.82 to 0.845 at 15C and the T95(D86) = 360C maximum are intended along with sulphur + 'natural' Cetane Index + 'engine tested' Cetane Number + Polynuclear Aromatics to ensure a high quality clean fuel, fully compatible with use in high speed diesel engines as well as medium speed diesel engines.
Very low values for T95(D86) imply shift to kerosene-oriented diesel fuels. This can decrease efficiency and km per liter as well as increase maintenance requirements. Higher values for T95(D86) can indicate very sloppy distillation operations and/or spiking with inappropriate components. Higher values can also increase soot going to the emissions control systems or into the atmosphere and can increase maintenance requirements.
Specific Gravity criteria along with Cetane values and PNA limit ensure a balanced molecular composition for the diesel gas oil fuel.