National Engineering Research Center of Oil and Gas Pipeline Transportation Safety/MOE Key Laboratory of Petroleum Engineering/Beijing Key Laboratory of Urban Oil & Gas Distribution Technology/China University of Petroleum, Beijing 102249, China.
National Engineering Research Center of Oil and Gas Pipeline Transportation Safety/MOE Key Laboratory of Petroleum Engineering/Beijing Key Laboratory of Urban Oil & Gas Distribution Technology/China University of Petroleum, Beijing 102249, China.
J Colloid Interface Sci. 2023 Jul 15;642:373-379. doi: 10.1016/j.jcis.2023.03.171. Epub 2023 Mar 31.
Wax molecules crystallize at ambient temperature, causing the crude oil to become a dispersed system, which poses challenges in the flow assurance of pipelines. Improving the cold flowability of crude oil is the fundamental solution to tackle these problems. Applying an electric field to waxy oil may markedly improve its cold flowability. The adhesion of charged particles on wax particles' surface under the electric field has been demonstrated as the essential mechanism of the electrorheological effect. However, the correlation between the accumulated charged particles and the induced viscosity reduction has not been explored quantitatively. In this study, the viscosity and impedance of four crude oils before and after electric treatment were measured. The conductivity changes of the oils' continuous phase were obtained by an equivalent circuit model. And then, the charged particles' concentration before and after electric treatment was calculated by the Stokes equation. The results showed there is a positive correlation between viscosity reduction and charged particle concentration reduction in the continuous phase. Importantly, this correlation is also quantitatively applicable to the results of ten different waxy oils which has been published. This study provides a quantitative basis for the mechanism of electrorheological behavior of waxy oils.
蜡分子在环境温度下结晶，导致原油成为分散体系，这给管道的流动保障带来了挑战。提高原油的低温流动性是解决这些问题的根本方法。在含蜡油中施加电场可以显著改善其低温流动性。已经证明，在电场下，带电粒子在蜡颗粒表面的粘附是电流变效应的基本机制。然而，累积的带电粒子与诱导的粘度降低之间的相关性尚未被定量探索。在这项研究中，测量了四种原油在电处理前后的粘度和阻抗。通过等效电路模型获得油连续相的电导率变化，然后通过斯托克斯方程计算电处理前后带电粒子的浓度。结果表明，连续相中粘度降低与带电粒子浓度降低之间存在正相关关系。重要的是，这种相关性也适用于已发表的十种不同含蜡油的结果。这项研究为含蜡油电流变行为的机理提供了定量依据。
