基于EHD的W/O乳状液脉冲静电破乳多尺度微观机理研究

With the worsening and low-quality of domestic heavy crude oil, pretreatment difficulty of crude oil greatly increases.In the environment of energy-saving and emission-reduction advocated by national "12 • 5" plan, how to improve electrostatic desalting and dewatering effect of crude oil emulsion become one of the urgent problem of petroleum chemical enterprise. This subject proposes the high-voltage high-frequency pulse power connecting to the micro emulsion breaking unit, with the aid of high-power high-speed digital microscopic imaging system to investigate the single, multiple droplets and droplet groups polarization deformation, excessive polarization, crushing process, crushing ways, coalescing time, migration coalescence and demulsifacation conditions of multi-scale micro demulsifacation mechanism in water-in-oil (W/O) emulsion electrostatic demulsification process based on electrohydrodynamics (EHD) theory. The coupling effect between continuous phase fluid flow characteristics and the dispersed phase droplets electrostatic coalescence behaviors during pulse electric demulsification process intends to be comprehensively studied, high frequency oscillation failure mechanism of oil-water interfacial film and pulsed electrostatic demulsification microscopic mechanism of W/O emulsion intend to be investigated, and the corresponding electrostatic demulsifacation theory model intends to be established. Meanwhile, the subject intends to reveal the internal mechanism of the problems in electrostatic demulsification process of heavy, low-quality crude oil emulsion profoundly, strives to explore the solution of equipment problems, which provides important theoretical basis for solving the problems such as operation instability, electric field collapse, serious corrosion and so on. What else, the theoretical results of the subject also have important theoretical guide meaning for other electrostatic coalescence separation process.

国内原油的重质劣质化日益严重，原油预处理难度大大增加，在国家十二•五规划大力倡导的“节能减排”的环境下，提高原油静电脱盐脱水效果迫在眉睫。本课题拟采用高压高频脉冲电源连接自行设计的微型破乳单元，借助高倍高速数字显微成像系统，基于电流体动力学(EHD)理论，针对油包水(W/O)乳状液静电破乳过程中单个、多个液滴及液滴群的极化变形、过度极化、破碎历程、破碎方式、融合时间、迁移聚并、破乳条件等微观破乳行为进行多尺度深入研究，考察脉冲静电破乳过程中连续相流体流动特性与分散相液滴静电聚结行为之间的耦合作用机理，探讨油水界面膜高频振荡破坏机制以及脉冲静电破乳微观机理，并建立相应的静电破乳理论模型，为重劣质原油乳状液静电脱盐脱水过程中现有设备存在的操作不稳定、垮电场、腐蚀严重等问题的解决提供重要的理论依据。同时，所形成的理论成果对于其它静电聚结分离过程也具有重要的理论指导意义。

随着国内原油的重质化和劣质化日益严重，原油预处理难度大大增加。在国家大力倡导“节能减排”的环境下，如何提高重劣质原油静电破乳效果，成为石油石化企业亟待解决的难题之一。本课题针对重劣质原油在预处理过程中出现的种种问题，基于电流体动力学(EHD)理论，对脉冲静电聚结破乳过程中单液滴的极化变形、失稳破碎、破碎条件、破碎历程、破碎方式；双液滴的静电极化聚并速率、聚并条件、融合时间；多液滴的聚并历程、聚并方式；液滴群的迁移聚并特性、成链规律及破乳条件等机理进行全面深入的多尺度微观实验研究。对高频高压脉冲电场作用下水链形成与消散特性、高频高压脉冲电场作用下水滴聚并速率的影响因素、无机盐/表面活性物质/电场参数等对高频高压脉冲电场作用下水滴成链特性的影响进行了深入研究，得到了无机盐浓度及类型、电场强度、电场频率、脉宽比等参数对液滴静电聚结规律的影响机制。基于多物理场耦合软件COMSOL及电流体动力学理论，系统研究了电场强度、电场频率、电场形式、液滴粒度、界面张力、连续相粘度等参数对油包水乳状液中水滴极化变形的影响规律；运用相场方法，考察了半正弦波电场条件下，电场强度、电场频率、液滴直径、液滴中心距、液滴夹角对油包水乳状液内液滴间聚并的影响规律，并对静电聚结机理进行深入研究；运用水平集的方法，考察了直流电场下，电场强度、电导率、界面张力和连续相粘度对液滴-界面聚并的影响，并进行液滴-界面聚并的显微实验研究。自制动态微型观察槽，使用显微实验方法，研究油水乳状液中水滴的动态迁移聚并行为，通过改变施加电场及流场的顺序，探究其耦合作用机制；改变极板形式，研究其对动态静电聚结效率的影响规律。对新疆特超稠油SAGD采出液开展静电深度脱水实验，获得重劣质W/O乳状液高压高频脉冲静电破乳机理。所得研究成果，为重劣质原油乳状液静电脱盐脱水过程中现有设备存在的操作不稳定、垮电场、腐蚀严重等问题的解决提供了重要的理论依据。