电脱盐单元严重乳化原因及对策

Causes of serious emulsification in electro-desalting unit and countermeasures

中国石油天然气股份有限公司乌鲁木齐石化分公司Ⅲ套常减压装置在加工高酸重质原油过程中,电脱盐单元乳化异常严重,脱后盐含量持续不合格,严重影响后续装置正常运行。从原油性质变化、生产工艺条件、破乳剂选型等角度分析了严重乳化的原因,提出了如下措施：（1）加强原油罐区管理,延长原油沉降时间,通过加注低温破乳剂,将脱盐脱水工序尽量前移,以减轻电脱盐单元压力;（2）优化换热网络,提高脱盐温度。对于高酸值高密度管输原油,将脱盐温度提到130-135℃以上,才能保证较好的脱盐脱水效果;（3）根据原油性质变化及时进行破乳剂筛选。

In processing high TAN heavy crude oil in the third atmospheric and vacuum distillation unit,the electro-desalting unit suffered from serious emulsification which led to off-specification of salt in desalted oil and normal operation of the downstream units was affected. The causes of serious emulsification are analyzed in respect of variation of crude oil properties,operating conditions and selection of de-emulsifier. The following measures are recommended：（ 1） the management of crude oil tank farm is strengthened,and the crude oil settlement time is extended. The low-temperature emulsion breaker is added to move forward the desalting and dewatering so as to reduce the load of electro-desalting unit.（ 2） The heat exchange train is optimized to raise the desalting temperature. For the high-TAN and high-density pipeline crude oils,the desalting temperature is raised to over 130 - 135 ℃ to have a good desalting efficiency.（ 3） The proper emulsion breakers are selected based upon variations of crude oil properties.