Synthesis And Evaluation Of Pour Point Depressants For Daqing Diesel Oil

Pour point depressant (PPD) can improve the low temperature flow properties of diesel oils, and lower the cold filter plugging point (CFPP) and solid point (SP) of diesel oils, therefore, improve the flexibility of diesel oil production and certainly increase the income of oil refineries. The current pour point depressants have poor sensitivity for Daqing diesel oil. The objective of this paper is to exploit new type PPDs which possess good sensitivity to Daqing diesel oil.Based on the detail of hydrocarbon compositions, carbon distribution and mass spectrum analytical data, it is indicated that the main resons for poor sensitivity of Daqing 0# diesel to commercial PPDs are the followings: there are much higher wax content and quite lower aromatic hydrocarbons cotent in Daqing 0# diesel oil compared to Qilu 0# diesel oil and Lanzhou 0# diesel oil and Qingdao refinery diesel oil. Results of DSC and photomicrography show that the machanism of PPD working on diesel oil complys with eutectic-adsorption theoretically. PPD is crystallized firstly in the diesel oil, and plays the role of crystal nucleus, therefore paraffin was crystallized sequently and adsorpts at the surface of the crystal nucleus. Polar groups in PPD can prevent the small wax crystals growing up and destroy the three-dimensional structure of large wax crystals, witch make the wax crystals highly dispersed in the oil. As a result, the flow ability of the diesel oil at low temperature is greatly improved.New type pour point depressants (PPDs) for Daqing 0# diesel called as MAV and MAVA were synthesized and evaluated in our laboratory. The optimal reaction conditions are in the following: the molar ratio of maleic anhydride, acrylate and vinyl acetate equals 1:2:1, the reaction temperature and time are 80°C and 10hours, respectively. It is found that the MAV can lower the cold filter plugging point of Daqing 0# diesel oil by 5°C. In addition, two kinds of paraffin crystal dispersants designated as P and M are synthesized, respectively. It is found that there was a synergistic effect between the paraffin crysral dispersant and the main component MAV. It is indicated that the two component depressants are more effective than the mono-component depressants in improving the cold flowability of distillate hydrocarbon fuel oils. For example, the depressants composed of M or P and MAV (1:4 in mass ratio) can lower the cold filter plugging point of the Daqing 0# diesel oil by 7°C.On the basis of laboratory test, an industrial pilot test was taken in Haike Petrochemical Plant, Dongying, Shandong. The the two component depressants composed of P and MAV called as MP shows good susceptibility to diesel oils, which could reduce the cold filter plugging point greatly and promote the diesel oil from 0# to–10# without influcening any other quality specifications obviously. Furthermore, the distillation yield of the straight-run diesel oil can be increased by 5% in mass and the preferable ecnomic income can be realized by using PPD depressants.