低温丙烯储罐的自动控制

Automatic Control for Cryogenic Propylene Storage Tank

大型低温储罐压力接近常压,环境变化极易引起储罐压力的变化,造成安全隐患。储罐装置控制系统和联锁系统采用独立的DCS和紧急停车系统(ESD);精度伺服液位计和音叉式液位开关用于储罐液位的测量、控制和联锁;采用流量平衡法检测丙烯输送管线的泄漏,温度检测均匀分布在储罐吊顶内表面、罐底内表面、罐壁内表面;采用3台压力变送器对储罐的压力进行测量、控制和联锁。应用表明:安全可靠的控制系统和联锁系统,既保障了储罐的安全运行又取得了良好的经济效益。

Large cryogenic tank pressure is close to atmospheric pressure. The change of external environment easily causes change of tank pressure, and influences the safe operation of storage tank negatively. The storage tank is equipped with a set of DCS and a set of ESD. DCS and ESD are fully independent. Precision servo liquid level meter and tuning fork liquid level switch are used for tank level measurement, control and interlock. Flow balance method is used to detect leakage of propylene conveying pipeline. Temperature detection is uniformly distributed on the ceiling inner surface of tank, bottom inner surface and inner surface. Three pressure transmitters are used for tank pressure measurement, control and interlock. The results show the safe and reliable control and interlock system can not only guarantee safe operation of storage tank, but also can achieve good economie benefit.