混炼含酸重质劣质原油的电脱盐技术选择探讨

Selection of Electro-desalting Technologies for Mixed Refining Poor-quality Acid Heavy Crude

茂名石化公司自混炼高酸原油后,原油脱前和脱后盐含量都明显提高,脱后平均盐含量达到7mg/L以上,2007年7月脱盐和脱水合格率分别仅为38.46%和20%。影响电脱盐过程的因素有电脱盐罐内部结构、破乳剂、脱盐温度、混合强度、脱盐罐内电场强度、油水界面控制、注水量等。根据国内同类装置经验,建议采取降低进厂原油的盐含量、水含量;加强生产操作管理,强化对电脱盐工艺各项指标的考核;将二级脱盐改为三级脱盐;采用超声波脱盐技术或高速电脱盐技术;针对原油特性加强对破乳剂的筛选和使用;进行电脱盐工艺条件的优化评定;采用热量前移方法对装置换热管网进行优化改造,提高原油进电脱盐罐温度等措施,以解决电脱盐后盐含量超标问题。

Since it began mixed-refining high-acid crude oils,SINOPEC Maoming Petrochemical Company has seen significant increases in the content of salt in the crude oil both prior to and after desalination.The average salt content after desalination is higher than 7mg/L.In July 2007,qualified desalted and dehydrated crude oil accounted for only 38.46% and 20% of all crude oil used.The factors affecting the electro-desalting process include the internal structure of the electro-desahing tank,emulsion breakers,desahing temperatures,mixing intensity,the electric field strength in the desahing tank,oil-water interface control,the volume of water injected,etc.Based on data from other domestic units of the same type,the author of the article suggests taking the following measures to reduce the salt content after electro-desalination within an accepted range ：reduce the content of salt and water in feedstock crude oils;strengthen production and operation management by stepping up the auditing of all specifications for the electro-desalting process ;upgrade the two- stage desalination process to a three-stage process;introduce ultrasonic desalting technology or high-speed electro-desalting technology;strengthen the selection of emulsion breakers in accordance with specific characteristics of crude oils;assess the optimization of electro-desalting operating conditions;optimize the heat exchange pipeline network by moving the heat source forward to raise the temperature of crude oils entering the electro-desahing tank.