非均匀高频脉冲电场中水滴成链规律研究

Investigation of water chain under non-uniform high-frequency pulsed electric field

近年来,由于原油中沥青质、胶质等含量的增大,电聚结过程中易产生长水链,一旦导通电极就会短路,使场强急剧下降,导致设备断电甚至损坏。为了防止长水链造成的危害,将同轴六边形-圆电极施加高频脉冲电场后,对水滴成链和聚并行为进行了观测和研究。结果表明,水滴在电场作用下成链、聚并,水链自电极中心向外延伸,水链长度随着电场参数和物性参数的改变而改变。随着电压幅值、频率和脉宽比的降低,水滴粒径增长率和水链长度同时下降;随着含水率和表面活性剂浓度的增大,水滴长度先增大后减小;随着含水率的增大,水滴粒径增长率先增大后减小;随着表面活性剂浓度的增大,水滴粒径增长率先减小后增大。上述结论揭示了非均匀高频脉冲电场中水滴成链和聚并是同一过程的不同阶段,并阐明了不同因素的影响规律。

The increase of asphaltene and colloids in crude oil makes droplets difficult to merge but easier to form long water chains.The bridge of electrodes by long water chains leads to short circuit that causes power supply interruption and equipment damage.Coaxial hexagon-circle electrode was applied by high-frequency pulsed electric field,and the processes of water chain formation and droplet coalescence were observed and studied in this work.The results show that the formation of long water chain and the coalescence of droplets are enhanced by electric field,and the water chain extends from center to periphery of electrode system.In addition,the water chain length and droplet growth rate change with the variation of electric field and physical properties.With the decrease of potential difference amplitude,frequency and duty ratio,the length of water chain and droplet growth rate decrease.The length of water chain increases then decreases with the increase of water cut and surfactant concentration.The droplet growth rate increases then decreases with the increase of water cut,which is the opposite when the surfactant concentration increases.These results indicate that the water chain formation and droplets coalescence are different stages of the same process,and the effects of different factors are clarified.