加剂模拟高蜡原油热性能的研究

Thermal Properties of Doped Simulation Waxy Crude Oil

用自由基溶液聚合法合成了丙烯酸十八酯/马来酸酐/苯乙烯共聚物,用正十六胺胺解共聚物中的酸酐基团,得到共聚物的不完全长链酰胺化产物,即为原油降凝剂PMB。以4种不同熔点的切片石蜡混合物在0号柴油中的溶液为模拟含蜡原油,以2℃/min的速率降温至约-50℃后升温测试,得到空白和加剂油的DSC曲线。含蜡25%的空白油,蜡晶型转变和蜡晶熔化溶解峰合并形成低宽峰,相变能29.28J/g,加剂(200μg/g)油的两峰分离,后一峰很尖,出峰温度上移,熔程变长,相变能148.5J/g,表明PMB参与共晶,且与蜡有良好的匹配性。含蜡30%的空白油的两峰明显分离。加剂量增大时(200600μg/g),起始峰温移向低温方向,放热量(相变能)有所减小,原油降凝幅度增大,对于含蜡25%的模拟含蜡原油(凝点35℃),凝点降低幅度由6.5℃增至17.5℃,与加剂温度20℃时相比,加剂温度为50℃时的平均降凝幅度平均增加2.5℃。

An octadecyl acrylate/maleic anhydride/styrene tercopolymer was synthesized by radical polymerization in solution and modified by reaction with cetylamine to convert the anhydride functionalities in the copolymer to amide ones and to give a partially amidated copolymer as flowability improver PMD for crude oil. A similation waxy oil（SWO） was prepared by dissolving a mixture of 4 microtomie waxes of different melt point in #0 diesel oil and the thermal properties of blank and PMD treated SWO samples were investigated on a DSC instrument by a procedure of heating at a rate of 2℃/min from about -50℃ ,to which the samples were cooled at the same rate. The blank sample containing 25% mixed wax displayed a low and broad exothermic peak, assigned to crystalline transformation and wax crystal melting, and gave a phase transition energy （ PTE ） of 29.28 J/g. For SWO sample treated by PMD at dosage of 200μg/g oil, the two peaks were separated each from other with melting peak being sharp and high, the onset of the peaks appeared at higher temperature, the melting range was wider and the PTE was increased to 148.5 J/g. These experimental phenomena showed cocrystallization of PMD with wax paraffins and conformance of PMD to the mixed wax. The two peaks above mentioned were well spearated for the blank SWO sample containing 30% wax. With increasing PMD dosage from 200 to 600μg/g oil in the SWO samples containing 25% wax, the onset temperature and the PTE became lower meanwhile the pour point depression （PPD） was increased from 6. 5 to 17.5℃ with the original pour point being of 35℃ for the blank sample and when PMD was introduced at 50℃, the PPD in average was by 2. 5℃ larger than that in the case the PMD was introduced at 20℃.