ULSD In A Nutshell
Ultra-Low Sulfur Diesel (ULSD) contains 97% less sulfur than low-sulfur diesel, and significantly higher amounts of dissolved water which causes cold weather freezing problems. The introduction of ULSD has made year-round fuel maintenance essential.
ULSD – What it Means
- ULSD contains up to a 10-fold increase of water (due to hydro-treating at the refinery) which increases cold weather freezing problems
- There is increased paraffin in ULSD, which crystallizes out of the solution in cold temperatures and agglomerates to form clouds of solids that plug filters and injectors when pulled into the fuel line
- While most of the sulfur has been removed from ULSD, there is still enough to combine with water and form a weak sulfuric acid that will corrode fuel tanks.
- The process of removing the sulfur in ULSD and off-road fuels reduces the ability of those fuels to lubricate fuel system components
- Lubricating agents added during the refining process to meet ASTM standards may not meet engine manufacturers’ recommended lubricity ratings
- Kerosene, a winter blend fuel additive for cold-weather operation, reduces lubricity further
- Diesel engines manufactured prior to 1/1/07 were designed to run on #2 diesel (5000ppm sulfur) or #2 LSD (500ppm sulfur). While ULSD (15ppm sulfur) can be used in these engines, the sulfur content is part of the lubricity package the engine was designed to run on
- Tier 3 engines (manufactured after 1/1/07) must use ULSD, but require engine oil with low ash content to avoid clogging the emission equipment
- The minimum cetane rating for ULSD is 40, while most engine manufacturers recommend 42-44
By Eliminating Free Water, K100
Eliminates cold weather freezing problems, lowers the temperature at which paraffin starts to agglomerate and prevents the formation of corrosion-forming sulfuric acid.
- Increases ULSD lubricity 20-40% (at a 1:500 mix ratio) – organically!
- Alters burn chemistry for more complete combustion leaving no ash deposits
- Increases the cetane rating 1-1/2 to 2 points