高酸重质原油的电脱盐技术选择

Selection of electro-static desalting process for high-TAN crude

中海石油宁波大榭石化有限公司主要加工渤海湾的低硫高酸重质原油,采用两级交直流电脱盐技术,脱后原油含水、含盐指标不合格。对电脱盐工艺和设备存在问题进行分析,决定对第一级电脱盐场及相关配套设备进行改造,第一级电脱盐采用高频和低频交直流相结合的电场设计方案,高频智能响应控制电源的三相交流电经过整流滤波得到连续可调的直流电,然后经过全桥式逆变器,产生频率、脉宽及幅值均连续可调的矩形波交流电,经过变压器升压变换后输出到负载,产生具有高穿透能力的高频电场,对乳化液产生强列冲击并使其破乳化。比较改造前后运行效果发现该技术在加工高酸重质原油等重质劣质原油时显示出优异性能,提高了电脱盐效率(提高了6个百分点),降低了脱后原油盐含量(降低了4个单位),基本满足内控指标,电脱切水的含油也大幅下降,降低了能耗,提高了企业的经济效益。

Lowsulfur HighTAN crudes from Bohai Bay were processed in CNOOC Ningbo Daxie Petro chemical Co. , Ltd. The twostage DC/AC electrostatic desalting process was applied for crude oil desalting, and water and salt in desalted oil failed to meet the specifications After analysis of existing problems in process and equipment of desalting unit, it was decided to revamp the 1 ststage desalter and associated equip ment. The 1ststage electric desahing adopted the combination of highfrequency and lowfrequency AC/DC electricity field. After 3phase AC electricity going through the rectification and filtration circuits, continuous adjustable electricity can be obtained. After gonging through the inverter, the rectangularwave AC electricity of continuous adjustable frequency, adjustable pulse wideness and adjustable amplitude can be produced and transmitted to the load after voltage elevation by transformer to generate highpenetration and highfrequency electric field. The electric field will produce strong shock and emulsify the emulsification liquid. The compari son of operation results before and after revamping shows that this technology offers excellent performance in processing highTAN heavy crude oil by increasing salt removal rate by 6 percentage points and reducing salt in salted oil by 4 units. The oil in blowdown water requirement is greatly decreased, the energy consumption is lowered and economic henefit is irnnrnved