Research And Design On Monitoring System Of Residual Heat In Flushing Slag Water For Heating

The blast furnace slag is the main by-product in the process of steel production,it is also a kind of very useful secondary resource.If the heating of the flushing slag water could be recovery,it can not only replace of traditional energy for heating but also can reduce the use of traditional energy and the pollution to the environment by the burning of traditional energy.Therefore,it has extraordinary economic benefit and social benefit.This thesis is based on the technological process of the new 1#blast furnace waste water residual heat heating in Benxi Iron and Steel Corporation.And a monitor system is designed for the blast furnace slag flushing water heating,which performs the monitor and control of technical process.This thesis elaborates in the following aspects based on the technological process:the system solution design,the model selection for PLC,valve and sensors;the implement of upper computer and lower computer.The hardware is a three-layer net framework composed of PLC(SIEMENS S7-300)series core controller,the devices are chosen on the basis of control task.Modularization design is used,so it is convenient for the upgrade and control management as well as maintenance of the whole system.The software is composed of the SIMATIC STEP7(match with the PLC of SIEMENS S7-300 series),and the program written on the PLC would control the valves,the water pump and the electric motor,as to the human-computer interface of host computer,the powerful WinCC configuration software is used,which can enable the rich picture,the man-machine interface dynamic display,parameter monitor faction,system control function,the fault diagnosis and alarming function as well as data report display faction.In addition,based on the coupling characteristics of the system and the contol requirements,this paper proposes the decoupling control program of secondary supply-return water temperature.Based on the physical mechanism of heat exchanger,this thesis builds the coupling relationship mathematical model among the primary side water flow,water flow secondary,secondary supply water temperature and secondary return water temperature for the simulation of decoupling control on secondary supply-return water temperature.Based on heat exchange station mathematical model,this thesis makes a simulation on secondary supply and return water temperature decoupling control system with feedforward compensation decoupling control and optimizes the parameters of PID controller by Genetic algorithm because of the shortage of the dynamic characteristic.At last,the control method is verified and analyzed by simulation experiments.