Cold flow properties are of particular concern with middle distillate fuels because they contain straight and branched chain hydrocarbons (paraffin waxes) that become solid at ambient winter conditions in cold climates. At sufficiently low temperatures, fuels with wax compounds will start to crystallize and impact the flow characteristics of the fuel. Three primary fuel specifications are used to minimize supply problems in cold climates including Cloud Point, Pour Point and Cold Filter Plugging Point.
- The Cloud Point (measured by ASTM D2500) is the temperature at which the first crystals of wax (usually linear alkanes) appear when a sample is cooled under standard conditions.
- The Pour Point (measured by ASTM D97) is the temperature at which a sample can just be poured when it is cooled down under standardized conditions. This point is 3˚C above the temperature at which sufficient wax has crystallized to prevent normal flow of the sample.
- The Cold Filter Plugging Point (measured by IP309) is the temperature at which sufficient wax has crystallized to block a specified filter when a sample is cooled down under standard conditions in specific equipment.
DuPont offers IsoTherming® Dewaxing Technology for the improvement of cold flow properties for the production of low and ultra low sulfur diesel. The technology will be tailored to meet the specific needs of the refiner by proper selection of catalyst systems and operating conditions.<o:p></o:p>