在现场原油处理过程中,原油经过一个一级分离器处理后会进入两个并列二级分离器。由于两个并列二级分离器位置不同,流体流经管道路径不一,产生分离器“抢液”的问题。在对二级分离器进出口流量进行理论分析的基础上，研究液位控制策略及压力控制策略的修改，对现场自动控制方式进行调整。研究得出,可通过采用以下措施成功解决两个并列二级分离器“抢液”的问题:1)改变原来单一的控制方式,灵活运用随动控制和单回路控制;2)采用多种控制模式切换;3)对 PID参数进行优化。经现场油田实际应用结果验证,控制方式调整后，两个二级分离器进液平稳,油水处理效果改善明显,水相出口含油由250 mg/L下降至120 mg/L,油相出口含水率由20%下降至12%。系统稳定性得到提高,上游来液波动影响明显降低。均衡进液后总处理能力提高约1 000 m3/d,提高了生产效率,降低了生产成本。

At one on-site crude oil treatment facilities, the crude oil passes through a primary separator before entering two paralleled secondary separators. Due to the different positions of the two parallel secondary separators with different piping configurations, there is an uneven distribution of liquid entering the two separators. Based on a theoretical analysis of the liquid flow at the inlet and outlet of the separators, the liquid level control strategy and vessel pressure control strategy are reviewed. The process control algorithm was modified following the study: 1. Replace the original single control scheme, with flexible use of servo control and single feedback loop control; 2. Switching between multiple control modes; 3. Optimizing PID parameters. The problem of uneven liquid distribution in two paralleled secondary separators was solved successfully. After one-year field application, the two secondary separators have a stable liquid inflow and the oil-water separation efficiency has improved significantly after modification of the control scheme. The oil content at the water-phase outlet drops from 250 ppm to 120 ppm, and the water content at the oil-phase outlet drops from 20% to 12%. The process system is more stable and the unfavorable influence of upstream flow fluctuation is significantly reduced. The total processing capacity after balancing the liquid distribution is increased by about 1000 m³/d, thereby improves the production efficiency and reduces the production cost.