高压电场作用下含蜡原油中带电胶粒与蜡晶作用机制

Mechanism on interaction between charged particles and wax crystals of waxy oils under high-voltage electric field

电场改性是一种新兴的含蜡原油改性方法,带电胶粒(胶质、沥青质)在电场作用下聚集于蜡晶表面是其主要机制。为明确带电胶粒与蜡晶的作用机制,选取电场降黏效果差异显著的两种含蜡原油,测试并分析电场作用前后油样的表观黏度、阻抗以及蜡晶晶胞参数。结果表明:电场作用后降黏效果显著的1#原油阻抗上升,但作用温度下蜡晶晶胞参数不变,再降温至2℃后,蜡晶晶胞参数变化显著;对于无降黏效果的2#原油,电场作用后其阻抗不变,降温后的蜡晶晶胞参数也没有变化;电场作用下含蜡原油中的带电胶粒吸附于蜡晶表面,是电场发挥降黏效果的必要条件;部分含蜡原油中带电胶粒自缔合从而无法在电场作用下吸附于蜡晶表面,是该类原油不具有电场降黏效果的原因。

The application of an electric field to the waxy oil near its pour point can significantly improve its cold flowability.The charged particles'accumulation on the surfaces of the wax crystals under the electric field is the essential mechanism of this method.This study aims to investigate the interaction between the charged particles and wax particles.Two types of waxy crude oils with significant difference of viscosity reduction under the action of electric field were selected.Then the apparent viscosity,the impedance,and the lattice parameters of the wax particles were measured.The results show that the impedance of oil 1#increases after the electric treatment,while the lattice parameters of wax particles at the treatment temperature remain unchanged,but they change dramatically after the oil sample is cooled to 2℃.Conversely,for waxy oil 2#whose viscosity cannot be reduced by the electric treatment,its impedance does not change after the electric treatment,and the lattice parameters of wax particles are also unchanged after being cooled to 2℃.The adhesion of charged particles on the surface of wax particles under the electric field is the essential reason for viscosity reduction.Additionally,the inability of some waxy crude oils to undergo viscosity reduction via electric treatment is due to the self-association of charged particles,which hinders their absorption on the surfaces of the wax particles.