Lubricity Research Backgrounder

Over the past several years diesel fuel regulations have undergone significant changes in an effort to reduce the environmental effects of engine exhaust emissions. The fuel processing required to meet these regulations has also resulted in substantial changes to the quality of diesel fuel. In many refineries throughout the world, diesel fuel is requiring treatment with hydrogen to improve its quality. The changes to fuel quality are mostly being driven by environmental regulations to reduce diesel engine exhaust emissions. The fuel properties that are most frequently being altered are aromatics level, ignition quality (cetane number) and sulphur content. Aromatics are being reduced, paraffinic material has increased, ignition quality or cetane number is being increased and sulphur content is being lowered. At most refineries, fuels are hydro-treated to reduce their sulphur and aromatics levels. As a result of hydro-treating, some of the important fuel qualities of diesel fuel are reduced. For example, if the hydro-treating process is very severe it can partially remove or even eliminate the naturally occurring compounds that provide a lubricating function for the fuel. It is possible to produce a fuel so low in these compounds that accelerated wear in diesel fuel injection equipment (FIE) will occur.

In Canada and the northern US more and more of diesel fuel that is consumed is derived from the Western Canada’s oil sands resource. To upgrade the oil sands bitumen to diesel fuel, the bitumen requires severe hydrotreating After the fuel is hydrotreated, it requires remedial action to replenish its lubricating qualities (this entails introducing additives to the fuel). However, as indicated above, most diesel fuel throughout the world will require increased hydrotreating to lower sulphur and reduce aromatics levels to meet environmental regulations. The legislation for these regulations have been or are being rapidly implemented by many countries throughout the world.

All of North America’s major oil companies are producing ultra low sulphur diesel (ULSD). AET has been involved with lubricity since the early 1990's. These early investigations involved the use of military jet fuel in diesel engines. More recently, AET has been assessing the impact of water in diesel fuel on on lubricity bench test measurements.

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