石油化工装置安全设计讨论——Ⅲ.自动控制安全设计

Discussion on safety design of petrochemical units——Ⅲ.safety design for automatic control

石油化工装置对高可靠性的仪表自动控制设计提出了更高要求,为避免和减少事故的发生、降低事故损失产生了积极的影响。重要控制系统的关键组件应考虑冗余配置;对可能发生重大事故的设备应设置安全联锁(SIS)系统;对因联锁停车可能引发相关联参数报警的报警点应选用能区别第一事故原因的报警系统;控制器按照"故障安全"的原则设计;控制仪表和安全仪表应分开独立设置;重要信息要用不同颜色、闪光指示和适当的数据显示;采用类别较高的电源作为仪表自动控制系统的工作电源;对电气设备、用电仪表、自控设备应设计良好的接地系统。

The safe operation of the petrochemical process units has a greater requirement for the design of reliable automatic control system so as to reduce the occurrence of accidents and minimize the losses. Redundant design shall be provided for the critical parts in the important control system,and safety interlock system（ SIS） shall be designed for the equipment which many be subject to larger accidents. The alarm system which can distinguish 1st-class accident shall be selected for the relevant parameter alarms. The controller shall be designed based upon the fail safe principles. The control instruments and safety instruments shall be designed separately. The important data and information shall be indicated by different colors,flashes and data. The electric power of higher class shall be provided for the electric power supply for instrument automatic control system. In addition,good grounding system shall be designed for the electric equipment,electric instrument,automatic control instrument,etc.