关键词: 聚丙烯酸酯 , 降凝剂 , 结晶性能 , 蜡晶形貌 , 降凝效果

Abstract: Using differential scanning calorimeter （DSC ）， the crystallization abilities of polyacrylate （PA） pour point depressant and waxy crude oils doped/undoped with PA were studied；then the morphology of wax crystals in the waxy crude
oils doped/undoped with PA was investigated through a polarized light microscope and the depressive effect of PA on Changqing and Qinghai waxy crude oils was evaluated by the pour point tests and rheological experiments．The results show that the crystallization ability of PA improved greatly by increasing the alkyl side chain length of PA but kept unchanged with the increase of average molecular weight of PA．The addition of PA can inhibit the wax precipitation and decrease the wax appearance temperature of waxy crude oils．The size of wax crystals become larger and the structure of them become compact after PA addition，leading to the great improvement of the low temperature rheology of waxy crude oils．The depressive effect of PA on waxy crude oils are related to the crude oil composition and the molecular structure of PA．With the increasing of wax content and the fraction of wax with large carbon number， the depressive effect greatly decreased． The average molecular
weight of PA affected its depressive effect by controlling the solubility of PA in waxy crude oils：the solubility of PA in crude oils decreased with increasing the average molecular weight of PA， thus reducing the interactions between waxes and PA molecules and inhibiting the depressive effect of PA．The better matching the alkyl side chain of PA with the carbon number ofwax in crude oils，the better depressive effect of PA．

Key words: Polyacrylate , Pour point depressant , Crystallization ability , Wax crystal morphology , Depressive effect