Effect of hydrolyzed polyacrylamide used in polymer flooding on droplet-interface electro-coalescence: Variation of critical electric field strength of partial coalescence
Effect of hydrolyzed polyacrylamide used in polymer flooding on droplet-interface electro-coalescence: Variation of critical electric field strength of partial coalescence
复制标题
聚合物驱用水解聚丙烯酰胺对液滴界面电聚结的影响：部分聚结临界电场强度的变化
DOI：
10.1016/j.seppur.2019.115737
复制
发表时间：
2019
影响因子：
8.6
通讯作者：
Lu Yuling
中科院分区：
文献类型：
--
作者：
Yang Donghai;Sun Yongxiang;Ghadiri Mojtaba;Wu Huanyu;Qiao Heming;He Limin;Luo Xiaoming;Lu Yuling
聚合物驱是石油工业中广泛采用的提高采收率的方法。然而，采出液中聚合物分子的存在会影响电脱水分离器中油水界面处液滴的聚结。通过高速记录和观察，研究了水解聚丙烯酰胺（HPAM）对液滴-界面聚结的影响。实验观察了聚合物水溶液液滴在电场作用下的变形。图像显示液滴塌缩成细丝而没有由于粘弹性而夹断。同时，细小的二次液滴从长丝顶端喷发出来，这对脱水效率不利。一个临界电场强度（Ecrit）超过部分聚结发生了确定。研究了初始液滴粒径、HPAM浓度、电场波形和频率对液滴粒径分布的影响。结果表明，Ecrit随初始液滴半径的减小或HPAM浓度的增大而增大。采用正弦交流、方波、脉冲直流和脉冲交流四种波形的交流或脉冲电场。频率的增加抑制了液滴在垂直方向上的电致拉伸，抑制了部分聚结。对于这些不同的电场，Ecrit随频率升高的增加遵循不同的方式。总体而言，Ecritof方波大于其他波形;然而，Ecritof PUAC和正弦AC波形在高频下可能超过方波。这些研究结果是有用的电脱水分离器的发展，在分散的水相中含有溶解的聚合物的油。
Polymer flooding is widely used in petroleum industry to enhance oil recovery. However, presence of polymer molecules in produced liquids can influence the droplet coalescence at oil–water interface in electric dehydration separators. In this study, the influence of hydrolyzed polyacrylamide (HPAM) on droplet–interface coalescence was examined through high-speed recording and observation. Deformation of droplets of aqueous polymer solution under electric fields was experimentally observed. The images showed droplets collapsed to filament without pinch-off due to viscoelasticity. Meanwhile, fine secondary droplets erupted from the summit of filament, which was detrimental to dehydration efficiency. A critical electric field strength (Ecrit) beyond which partial coalescence occurred was identified. The effects of the initial droplet size, HPAM concentration, electric field waveform and frequency were explored. The results showed thatEcritincreased with the decrease in initial droplet radius or the increase in HPAM concentration. Four kinds of AC or pulsatile electric fields (PEFs) were used including sinusoidal AC (sine AC), square, pulsed DC (PUDC) and pulsed AC (PUAC) waveforms. The increase in frequency suppressed the electro-induced stretching of droplets in the vertical direction, inhibiting partial coalescence. For these different electric fields, the increase inEcritwith elevated frequencies followed different ways. Overall,Ecritof square waveform was larger than those of other waveforms; however,Ecritof PUAC and sine AC waveforms may exceed that of square waveform at high frequencies. These findings are useful for the development of electro-dehydration separators for oils containing dissolved polymers in the dispersed aqueous phase.