Research And Design Of The Natural Circulation Boiler Control System

Boiler as a very important energy conversion equipment,it provides energy for the production of enterprises,widely used in chemical,power plants,oil and other industrial areas.However,there are many problems in the domestic boiler system because of many reasons,such as inadequate combustion,low output,heat loss,etc.In recent years,automation technology is developing rapidly,computer cost also is on the decline.At the same time,computer control system has high degree of automation,stable and accurate,so the design of computer automatic control system to the economic,safe and stable operation of the boiler system.Advanced multi-functional process control training system SMPT-1000 is the semi physical simulation equipment to simulate the whole process system of the water vapor thermal energy of natural circulation boiler and evaporator.The boiler system of SMPT-1000 as the main research object,the process of boiler are analyzed,the main parameters of the liquid level,flow,pressure,temperature as the controlled variable,the characteristics of each parameter in a detailed analysis,according to the characteristics of different parameters,respectively,different control schemes are designed.At the same time,aiming at the nonlinear and lag characteristics of the steam temperature,the advantages of high reliability,small steady-state error of the traditional PID control algorithm and the good robustness and flexibility of fuzzy control algorithm are combined.Fuzzy-PID composite control algorithm is used to control the temperature of superheated steam,achieved by SCL programming language.According to the control requirements,the basic process control system,the sequence control of the drive system and the security system are designed.Using the SIEMENS PCS7 distributed control system to form the software and hardware and the SIMATIC PCS7 Wincc software to control and monitoring the operation of the boiler system according to the control scheme requires.Through the parameter curves in the running process of the semi simulation equipment SMPT-1000 boiler system,we can see that the basic process design of the control system,drive sequence control system and safety system,etc,operates well,can achieve the requirements,verifying the feasibility of the control strategy and scheme in the thesis.