Research And Development On Monitoring And Controlling System Of Residual Heat In Blast Furnace Waste Water For Heating

The blast furnace slag is one of the by-products during the production of steel andit is also a very useful secondary resources. If the blast furnace slag waste water can berecycled and employed in heating, it can not only solve the problem of heatingresources nearby factory but also can reduce the amount of water used in blast slagflushing, and then, it can minimize the environment pollution. Therefore, it hasextraordinary economic benefit and social benefit.According to the technological process of1750m3blast furnace waste waterresidual heat heating in Jinan Iron and Steel Corporation and the huge fluctuationproblem of high temperature flush slag, an monitor system is designed for the blastfurnace slag flushing water heating, which perform the monitor and control of technicalprocess. This paper elaborates in the following aspects: the system solution design; themodel selection for PLC, frequency converter and sensors; the implement of uppercomputer and lower computer. The hardware is a three-layer net framework composedof PLC (SIEMENS S7-300) series core controller, the devices are chosen on the basis ofcontrol task. Modularization design is used,so it is convenient for the upgrade andcontrol management as well as maintenance of the whole system. At the same time, dueto the requirement for control function, the frequency-variable controller design isapplied, which achieved energy saving,stable and reliable controlling effect. Thesoftware is composed of the SIMATIC STEP7(match with the PLC of SIEMENSS7-300series), the water pump and electric motor are controlled by adjusting thefrequency of the transducer, as to the human-computer interface of host computer, thepowerful WinCC configuration software is used, which can enable the rich picture,theman-machine interface dynamic display, system control function, data report displayand printing function as well as the fault diagnosis and alarming function.The monitoring and controlling system of residual heat in blast furnace waste waterfor heating designed in this paper, is able to meet the requirements of continuousheating in the condition of blast furnace slag is not continuous. At present, the systemhas been applied to the1750m3blast furnace waste water residual heat heating in JinanIron and Steel Corporation. The results showed that: the system can achieve heattransfer station unmanned, remote monitoring, effectively reducing system operatingcosts, saving energy, improving production efficiency.