Below is some additional information from Power Service as it relates to demulsipher/emulsiphers in diesel fuel.
Here is a discussion from the Chemist at Power Service.
All diesel fuel has water in it. The water that is in diesel fuel normally will not hurt or harm the motor, pumps or injectors. Ultra Low Diesel Fuel (S15) will have about 30-75 ppm water. Biodiesel can contain as much as 1500 ppm and remain clear. Biodiesel blends with diesel fuel typically contain more water than diesel fuel, as much as 300 ppm. Warm fuel will carry more water than cold fuel. When the water content of the fuel gets up to 100ppm or higher, the more likely fuel filter icing will occur when the temperatures become severe. In the winter months when the temperature drops below freezing, these water droplets can freeze on the filter face of the water separator causing the flow of fuel to stop, even though the fuel is still liquid. It does not take much water to cause “fuel filter icing” problems. Also, as the temperatures drop, water in the fuel can fall out depending on how much water is in the fuel and how cold it gets, which adds to water problems. Also, the water separator can squeeze out this water which can freeze on the filter face and cause the fuel to stop flowing through the filter even though the fuel is still liquid. This is called “Fuel Filter Icing” and is often mistaken for fuel gelling. Fuel filter icing problems can be dealt with effectively by appropriate use of additives, such as Power Service Diesel Fuel Supplement® + Cetane Boost®, Clear-Diesel Fuel and Tank Cleaner®, and/or Diesel 911®. Diesel Fuel Supplement® + Cetane Boost® will also prevent diesel fuel from “gelling” down to as low as -40oF temperatures and minimize wax plugging of fuel filters at temperatures as much as 20-30oF below the cloud point of the fuel.
Power Service Diesel Fuel Supplement® + Cetane Boost® and Diesel Kleen® +Cetane Boost® have been formulated to contain the most advanced injector cleaning technologies. These technologies provide maximum injector clean-up of injection deposits in all fuel injection systems, including High Pressure Common Rail (HPCR) systems installed on 2007 and newer engines. The engine operational improvements are significant:
• Increased MPG up to 8% with DK+CB® — fuel savings exceed cost of additive
• Increased power and reduced need for downshifting
• Smoother and quieter engine operation
• ULSD Compliant — contains less than 15 parts per million (ppm) sulfur
• Effective in all diesel fuels, including ULSD and biodiesel
Power Service Diesel Fuel Supplement® + Cetane Boost® and Diesel Kleen® +Cetane Boost® contain a "demulsifier". Demulsifiers prevent detergents from “emulsifying” water into the fuel during turbulent conditions. Demulsifiers tend to cause excess water to coalesce and precipitate from the fuel and do not harm water separator/coalesce filters.
ASTM D7261 - 08 Standard Test Method for Determining Water Separation Characteristics of Diesel Fuels by Portable Separometer
Significance and Use
This test method provides a measure of the presence of surfactants in diesel fuels, and can be performed in the field or in a laboratory. Like Test Method D 3948 used for jet fuel, this test method can detect traces of some refinery treating chemicals left in fuel. It can also detect surface active substances added to or picked up by the fuel during handling from point of production to point of use.
Certain additives, which can act as weak surfactants, give a slightly reduced DSEP rating. Other substances which are strong surfactants give much lower DSEP ratings.
While filter separators have not been common in diesel fuel systems, they could become more prevalent with ULSD containing increased additive content to ensure clean, dry fuels in new engine designs. Weak surfactants, with slightly reduced DSEP ratings, do not affect the ability of filter separators to separate free water from the fuel. Strong surfactants give a much lower DSEP rating and adversely affect the ability of filter separators to separate free water from the fuel.
Results from this test method do not have a known relationship to the rate of water settling in tanks.
The Micro-Separometer has a measurement range from 50 to 100. Values obtained outside of those limits are undefined and invalid.
1.1 This test method covers a rapid portable means for field and laboratory use to rate the ability of diesel fuels (both neat and those containing additives) to release entrained or emulsified water when passed through fiberglass coalescing material.
1.2 This test method is applicable to diesel fuels such as D 975 Grade No. 1 and Grade No. 2 of all sulfur levels, and MIL-F-16884, naval distillate fuel (NATO F-76).
Also, use of Diesel Fuel Supplement® + Cetane Boost® and Diesel Kleen +Cetane Boost will not harm oxidation catalysts or diesel particulate filters on 2007 or newer engines.
Last edited by cssnms; 01-15-2013 at 11:59 AM.