Chemical Modification Research Of Wax Crude Oil

The operating mechanism and rules of crude oil depressants were studied by thermal analysis technology(DSC) , optical microscopy and rheology measurement technology in this paper based on crude oil rheology knowledge.The crystalline characteristics of ethylene vinyl-acetate (EVA), polyurethane-acrylate (PA) and polyurethane–acrylate–aerylonitrille (PA-AN) were studied by differential scanning calorimeter (DSC). Particular attention is given in this work to the effect of the vinyl acetate content and molecular weight on EVA copolymer's crystalline characteristics, the effect of side-chain and molecular weight on PA copolymer's crystalline characteristics, and the relationship of body–proportion with PA-AN copolymer's crystalline characteristics.The results of experiments are as follows:①the EVA copolymer's crystalline temperatuture and crystalline enthalpy decrease with the increase of vinyl acetate content, but the molecular weight of EVA has little effect on its copolymer's crystalline characteristics. The crystalline enthalpy decreases punily along with the increase of the EVA molecular weight.②As the length of side-chain increases, the crystalline temperatuture and crystalline enthalpy of PA copolymer also increases, while molecular weight has litle effect on the EVA copolymer's crystalline ability③PA-AN copolymer's crystalline temperatuture and crystalline Enthalpy decrease along with the the increase of aerylonitrille.The effect of depressants on the enthalpy of wax precipitation was studied by differential scanning calorimetry (DSC). The influence of pour point depressant for crystal morphology of crude oil was studied by polarizing microscope. On the basis of the above, the operating mechanism of crude oil depressants was discussed and analyzed in depth. The results of the studies are as follows:①The enthalpy of wax precipitation is disturbed by pour point depressants in that the depressants increase solubility of the wax and decrease the wax precipitation temperature or the peak temperature.②The waxy crystal in crude oil without modifier is thinner, in larger scale and is distributed in wide range in the oil. The system has higher surface energy. While the waxy crystal in the crude oil with the addition of pour point depressant saggregates and forms larger wax granular, thus inhibits the formation of wax crystal network.The effects of pour point depressants including EVA, PA and PA-AN on Baibao and Qinghai crude oil were examined, and the rule of the effect of the molecule structures of depressants on their modified effect was obtained. In addition, the rule of depressant combination was studied and the result indicated that the combination of pour point depressant could enhance the modified effect of depressants.