高酸原油电脱盐存在的问题及对策

摘要

The problems and solution of electric desalting of high-TAN crudes were described and summarized.The main problems in electric desalting of high-TAN crudes were heavy emulsification of oil and water,off-specification of desalting and dehydration and high electric current required for desalting operation,etc.The solutions were explored in respect of desalting process conditions,new equipment and desalting agents.Based upon the characteristics of high density,high TAN and high metal content of crude oil,the desalting process conditions should be optimized,the desalting temperature be properly elevated,the water injection and mixing intensity be increased and pH valued be strictly controlled;The design of direct entering of crude oil into the electric field,the pulse power supply and auxiliary ultra-sonic desalting system can help to improve the desalting efficiency of high-TAN crude in certain degree;In addition,the application of assistant agents such as demetalization agent,moisturing agent and asphalt dispersion agent especially demetalization agent could remarkably reduce the emulsion of crude oil and water and improve the desalting and dehydration rates to lower the water and salt in crude oil to less than 0.3% and 2 mg/L respectively.The compositions,forms and interface properties of emulsified liquid from high-TAN crude oil need to be further studied.%对高酸原油电脱盐过程中存在的问题以及解决方案进行了阐述和总结。高酸油加工电脱盐存在的问题主要包括油水乳化严重、脱盐脱水不达标和脱盐电流大等。文章从电脱盐工艺条件、新设备和脱盐药剂等3个方面介绍了解决这些问题的方法。依据高酸原油密度大、酸值高、金属含量高的特点,应强化电脱盐工艺操作条件,适当提高温度、洗涤水注量及混合强度,并严格控制洗涤水pH值;设计原油直接进入电场区域以及脉冲供电电源、超声波辅助脱盐系统等可在一定程度上提高高酸油的脱盐效果;一些助剂如脱金属剂、润湿剂、沥青质分散剂,尤其是脱金属剂的应用能够明显改善油水乳化程度以及提高脱盐脱水率,使原油含水小于0.3%,盐的质量浓度小于2 mg/L。但仍需从高酸油形成乳化液的组成、形态及界面性质方面进行深入研究。