电场强度对原油乳化液破乳脱水的影响

Effect of Electric Field Strength on Crude Oil Emulsion's Demulsification and Dehydration

为选择合适的脱水电场以提高对原油乳化液的脱水效率,试验研究了不同电场强度下乳化液的脱水效率。通过水滴极化模型的建立,推导出水滴在电场中的极化电荷量及水滴间的聚结力,并得到水滴破裂的临界电场强度表达式,以此在理论上确定了最佳脱水电场强度。研究结果表明:水滴聚结的偶极力与外施电场强度、水滴半径和水滴间距有关,不同半径和间距的水滴存在不同的临界脱水电场强度;当外施电场强度小于临界电场强度时,随着外施电场强度的增加,脱水率呈上升趋势,但当外施电场强度超过水滴破裂临界电场强度时,脱水率随电场强度的增加而下降。得到的临界脱水电场强度表达式与试验结果的一致性较好,可作为确定最佳脱水电场强度的理论依据。

In order to fmd an appropriate electric field for enhancing the dehydration of crude oil emulsion, we experi mentally investigated the emulsion dehydration efficiency under different electric field strengths. Moreover, we derived the polarized charges of water droplets in electric field and the polarization force between the water droplets after estab lishing a polarization model of water droplets, and consequently obtained the expression of critical electric field strength for water droplet breakdown, which helps to theoretically determine the optimal dehydrated electric field strength. The experimental results show that the coalescing force between water droplets is influenced by applied electric field strength, water droplet radius and water droplet spacing. There is different critical dehydration electric field strength for water droplets with different radii and spacing. When an applied external electric field is weaker than the critical breakdown strength, the dehydration rate rises with the enhancing external electric field. Once the external electric field exceeds the critical breakdown strength, the dehydration rate will decline with the enhancing external electric field. It is concluded that theoretical critical dehydration electric field agrees with test results well, providing a theoretical basis for the deter mining the optimal dehydration electric field in oil production.