Abstract: Cold filter plugging point (CFPP) is an important index for diesel quality, which can reflect the actual performance of diesel engine at low temperature. The reason analysis for the higher CFPP of diesel fuel produced in the two diesel hydrofining units of Lanzhou refinery in 2015 was conducted. It was recognized based on the data analysis that the cold filter plugging point of diesel fuel was affected by crude oil composition. Two measures then were adopted: reducing the 95% distillate temperature of No.3 side stream of atmospheric and vacuum distillation unit and dewaxing the tope fraction of vacuum distillation tower to optimize the feedstock for diesel hydrofining devices, resulting in qualified CFPP of diesel oil, which is of benefit to the blending factory for the storage and market of qualified diesel fuel.

Key words: diesel, cold filter point, optimization of raw material composition, dewaxing process