Research Of Preventing Splashing Of AOD Furnace System Based On Fuzzy Control

In the metallurgical industry, AOD uses O2instead of electric, it simplified the production working procedure and reduces the production cost, it more and more attracts much attention. But the temperature of AOD smelting low-carbon ferroalloy is more1000℃above then others.So it causes the splashing accident in the smelting process. The splashing accident will bring the equipment trouble, the material outflow, the economic loss even personnel casualty. Therefore it is very important to control AOD splashing.This paper takes the AOD furnace as the object, studies how to control AOD splashing according to smelting characteristic. Clearly knowing the reason of AOD furnace splashing and find the solution according to the splashing reason.Choosing the signal that can characters splashing,using the signal to contol other variables that can stop from splashing,to maintain the variables in automatically the normal smelting scope. Launches the following work regarding the above thought:Firstly, through the contrast with temperature soft measuring technique and the intensity of sound soft measuring technique, determines the AOD furnace’s intensity of sound signal is the attribute splashing characteristic signal in the smelting process. Establishing the intensity of sound and Σ (Cr2O3) relational model, then using intensity of sound to attribute splashing. Completing the intensity of sound gathering system’s hardware, according to the signal which gathers to detennine that the intensity of sound scope of normal, splashing or return to metal.Secondly, researching the system’s technological design of air-supply system、the top gun system and the feeding system. In the same as normal smelting process AOD furnace, analyzing the position with time change curve of the top gun、the flow with time change curve of oxygen、the flow with time change curve of nitrogen、the speed with time change curve of feeding system. Providing the basis for the fuzzy controller’s design next.Thirdly, The characteristic of AOD furnace producing ferroalloy are that the production process nonlinear, the material indefinite, the variable coupling relations closely, following many kinds of chemical equilibria and the energy balance. So it is unable to establish the mathematical mode of splashing, then fuzzy control is suitable for the splashing control system. Dividing the different partitions of the sound’s intensity dased on Fuzzy Control of multilayer rules.Then controlling the gun position、the oxygen flow、the nitrogen flow and foam inhibitor through different partitions of the sound’s intensity. Completing the fuzzy controller’s design. Simulating the system with Matlab.We can see System stability time is different by intensity of sound falling into the different partition. because the four kinds of outputs have different influences to the physics and chemistry response speed of AOD furnace. But the system is a stability system.Its stability time is below60s, then the intensity of sound will stabilize in30-50normal ranges.Last, desiging the DCS control system of preventing splashing in the ferroalloy refining of AOD furnace. The Whole design thought of preventing splashing in the ferroalloy refining of AOD furnace is as follows. Examining the intensity of sound signal in the AOD furnace,then diliver it to PLC through the simulation quantity module. PLC will control the gun position、 the oxygen flow、the nitrogen flow and foam inhibitor with good programs. It Also can on-line monitor the work status of PLC with MP377-15. The DCS control system of the paper mainly designs air-supply system, the oxygen gun jacking system, the feeding system that influence splashing system.