Sulphur and diesel lubricity

Sulphur for lubricity and its dramatic reduction in diesel fuel has been a hotly contested camp fire debate since the early 2000’s

Lubricity is most commonly defined as the ability of a fluid to minimize the degree of friction between surfaces in relative motion under load conditions.

When lubricity is not at a satisfactory level, fuel pumps and injectors are prone to excessive wear and premature metal damage, the results of such wear are inefficient performance, shortened service life and high replacement costs.

The importance of adequate fuel lubricity has increased dramatically since critical fuel system parts must perform at evermore demanding operating pressures and temperatures and with greater degrees of metal to metal contact.  Obviously, these factors explain why lubricity quality is of prime importance to maintain pump and injector serviceability.

Australia’s diesel sulphur content in the 1990’s was five thousand parts per million, by 2009 it was down to ten parts per million.

Sulphur is a natural component of crude oil that diesel is derived from and is one of the key catalysts for soot production during combustion, resulting in health and environmental issues that have now been greatly reduced, however the mechanical health of the diesel fuel system has suffered as sulphur was and is an excellent lubricant. All diesel pumps and injection systems need lubricity to function efficiently, this is even more so as injector rail pressures have increased from the 1990’s 5.000 psi when diesel had 5.000 ppm of sulphur up to 36.000 psi with 10 ppm of sulphur today.

As low sulphur emissions became mandatory, diesel refiners had to develop new processes to reduce the sulphur content in order to meet the emission standards, the most cost effective method being hydro treating, during this process the sulphur is removed and replaced by hydrogen.

Unfortunately hydrogen is a highly reactive element; it reacts with other components in the diesel removing the polar and aromatic compounds that produce the lubricating qualities of high sulphur diesel.

Consequently we have an element (sulphur) that is a natural by-product of the oil industries refining process that has cost millions of dollars to remove, that they now have to spend millions of dollars to replace with a lubricity additive to meet the Australian Fuel Standard.

Anyone who has to deal with or abide by Australian Standards will know that they are the absolute minimum requirement, currently that equates to the lubricity additive being refinery introduced at between 100 parts to 300 parts per million, dependent on the refinery, feedstock and the particular lubricity additive package being used.

Treating your diesel with Fuel Doctor at one millilitre per litre equates to 1,000 parts per million with the added benefits over and above the increased lubricity of detergency for cleaning valve faces, fuel pumps, injector rails and injectors whilst dispersing moisture, fungal material and extending the life expectancy of your fuel system, as well as stabilising stored fuel for up to five years.

Every time you treat incoming fuel with Fuel Doctor you are taking the quality assurance of that fuel in to your own hands, by increasing its detergency and lubricity and protecting your fuel system from any unforeseen contaminants.

Fuel Doctor the multifaceted Australian Diamond that controls and prevents all elements of fuel degradation and contamination.