Design And Realization Of Process Detection And Control System For Large Blast Furnace Hot Blast Furnace

As important equipment in the blast furnace ironmaking process,the Hot Blast Stove is a key enabler of the continuous and stable production of the blast furnace in view that it can get stored the heat generated by burning gas via heat exchange and meanwhile,when blasting,turn the cold blast from the blower into hot blast by heat exchange and then transfer it to the blast furnace for ironmaking.Therefore,an efficient combustion control system is of great significance to blast furnace ironmaking because it can increase blast temperature,lower energy consumption and improve product quality.Hence,this thesis gives an elaboration on the design as well as the realization of the process detection and control system of blast furnace hot blast stove in the context of the new system engineering of blast furnace ISDEMIR 4 which consists of a 3000m3 blast stove and corresponding supporting facilities,with a design scale of 2.1 million tons per year.This paper starts from a brief introduction to the development of hot blast stove,and then focuses on the designs of the fuzzy controller according to the different characteristics of the three stages in the hot blast stove combustion process,namely,the initial combustion stage,the dome temperature management stage and the flue gas temperature management stage,with an aim to modify the air-fuel ratio,optimize the combustion operation and increase the cold blast supply temperature.In the initial stage of combustion,on the premise of guaranteeing the residual oxygen content in the flue gas,the maximum gas volume is used to correct the air-fuel ratio with the help of the fuzzy controller at the initial stage of combustion so that the vault temperature can rise to the set value as soon as possible.In the dome temperature management period,under the premise of guaranteeing the vault temperature,the air-fuel ratio is amended by the fuzzy controller for the vault temperature management period so as to ensure that the flue gas temperature can rise to the set temperature and thus the heat storage time of the hot blast stove is guaranteed.In the period of flue gas temperature management,the air-fuel ratio is modified by the fuzzy controller in the period of waste gas temperature management,thus enabling the flue gas temperature to reach the set value and the combustion of hot blast stove to be completed.To sum up,using the fuzzy controller with subsection control to modify air-fuel ratio can improve heat exchange efficiency and save energy.This thesis mainly completes the design of process detection and control system of hot blast stove,realizes the air-fuel ratio correction fuzzy controller of staged combustion in PLC program,and carries out field debugging,which shows good control effects according to the feedback from the actual operation on site.