基于PCS7和SMPT1000的蒸发器控制系统设计与实现

Design and implementation of evaporator control system based on PCS7 and SMPT1000

蒸发器设备是带有相变的多输入-多输出换热装置,具有大惯性、大时滞和非线性等变量属性。根据工艺流程和控制要求,设计了蒸发器的四个控制回路,分别是温度控制回路、液位控制回路、浓缩液组分控制回路以及浓缩液流量控制回路。浓缩液组分根据物料平衡原理采用了软测量技术,核心控制算法使用带有初始开度的复合PID控制算法,并详细说明该算法的工程调试方法和经验。在西门子PCS7过程控制系统平台和SMPT1000高级多功能过程控制实训装置实施了上述控制策略;研究结果表明,各被控变量的稳态指标和动态指标都远超用户控制要求。

The evaporator is a multi-input-multi-output heat exchanger with phase change,which has such variable properties as large inertia,large time delay and non-linearity.According to the process flow and control requirements,four control loops are designed,which are for temperature,liquid level,concentrated liquid component and concentrated liquid flow.According to the principle of material balance,soft measurement technology was adopted for concentrate component.The compound PID control algorithm with initial opening was used as the core control algorithm of the system.The engineering debugging methods and experience of the algorithm was descripted in detail.Above control strategy is implemented in Siemens PCS7 process control system platform and SMPT1000 advanced multi-function process control training device.The results show that the steady state and dynamic indexes of each controlled variable far exceed the user control requirements.