The effect of cooling processes on the yield stress of waxy model oil with nanocomposite pour point depressant
The effect of cooling processes on the yield stress of waxy model oil with nanocomposite pour point depressant
复制标题
冷却过程对纳米复合降凝剂蜡质模型油屈服应力的影响
DOI：
10.1016/j.petrol.2018.12.084
复制
发表时间：
2019-04-01
影响因子：
--
通讯作者：
Gong, Jing
中科院分区：
文献类型：
--
作者：
Huang, Huirong;Wang, Wei;Gong, Jing
晶体形态对蜡质油的宏观性能有显著影响，从而决定了蜡质油的流变行为。从结晶成核和生长的角度研究结晶对蜡质油流变性能的影响是至关重要的。本文在研制的纳米复合降凝剂（NPPD）和常规降凝剂（EVA）的基础上，重点讨论了步进冷却频率对未掺杂/降凝剂（PPD）掺杂蜡质模型油屈服应力和固有晶体形态的影响。结果表明：步进冷却频率对未掺纯蜡油的屈服应力影响不大；同样，蜡晶形貌表明，未掺杂油中的蜡晶对阶梯冷却频率不敏感。而对于掺有NPPD或EVA的蜡质油，频率越高，屈服应力越低；同时，掺油中蜡晶的数量增加，晶体形态在掺油中变得更加分散。结果表明，随着频率的增加，NPPD对屈服应力的修正效果更好。它实际上反映了PPD在不同阶跃冷却频率下结晶成核和生长的内在本质。
The crystal morphology has significant effect on the macroscopic properties of waxy oil, which indeed determines the rheological behavior of waxy oil. It is critical to investigate the influence of crystallization on the rheological properties of waxy oil from the insight of crystal nucleation and growth. In this work, the effects of step-cooling frequencies on the yield stress of undoped/pour point depressant (PPD) doped waxy model oil and inherent crystal morphology were particularly discussed, based on the developed nanocomposite pour point depressant (NPPD) and conventional PPD (EVA). Results reveal that step-cooling frequency has little effect on the yield stress of undoped pure waxy oil; similarly, morphology of wax crystal exhibits that crystals in undoped oil appears insensitive to the step-cooling frequency. However, for waxy oil doped with NPPD or EVA, the higher the frequency, the lower the yield stress; meanwhile the amount of wax crystals increases and the morphology of crystals turn to be more dispersed in doped oil at high frequencies. Results indicate that NPPD provides better modification effect on the yield stress with the frequency increases. It actually reflects the inner nature of crystal nucleation and growth with PPD at different step-cooling frequency.