Study on Commercial Pour Point Depressants Lowering Cold Filter Plugging Point for Daqing Diesel Fuels

Ethylene-vinyl acetate copolymer is widely used as commercial pour point depressants (PPDs) all over the world. The authors describe four commercial PPDs for evaluating the sensitivity of Daqing diesel fuels. The content and carbon number distribution of n-alkanes in the Daqing diesel fuels were analyzed by high-temperature gas-phase chromatography. The structures of the commercial PPDs were confirmed by IR spectra. The results indicate that the n-alkanes carbon distributions display an obvious normal distribution in the Daqing diesel fuels. Commercial PPDs can maximumly depress cold filter plugging point of the tested diesel samples by 7°C, 3°C, 5°C, and 0°C, respectively. The distributions of high carbon n-alkanes are all narrow so that wax crystals precipitate more easily at low temperatures, and as a result, the interaction between PPD molecules and wax crystal molecules is not good.