- Sep 28, 2017 -
Evaporative cooler system is one of the three subsystems of converter dry dust removal, and it is also the key link to ensure the effect of dust removal. The high temperature flue gas produced during the process of converter steelmaking is first trapped by the active hood and then passed through the vaporized cooling flue to cool the flue gas for the first time while recovering the heat. General vaporization cooling flue outlet temperature is about 800-1000 ℃. And then into the evaporative cooler by evaporative cooling way to the second cooling of the flue gas, while trapping coarse particles of dust. To meet the temperature conditions of electrostatic precipitator work, evaporative cooler outlet temperature is generally controlled in the 170 ~ 250 ℃ range. After the cooling of the flue gas into the electrostatic precipitator for fine dust, dust collector outlet dust concentration ≤ 10mg / Nm.
Evaporative cooler in this process plays a role in the past, the electrostatic precipitator has a great impact on the normal work. If the evaporator cooler outlet temperature is too high, the flue gas is not allowed to enter the electrostatic precipitator, because the flue gas temperature is high, dust than the resistance increases, it is not conducive to dust, flue gas temperature directly affect the dust removal efficiency, and the impact is more obvious. If the evaporator cooler outlet temperature is too low, in the capture of coarse particles of dust at the same time prone to wet bottom, wall phenomenon, increase the evaporative cooler ash delivery system maintenance, serious impact on the converter production, and the temperature is too low flue gas Into the electrostatic precipitator will cause condensation, condensation will cause the shell corrosion or high voltage creepage. Evaporative cooler temperature control system is not only related to the converter a dust effect but also related to the normal production of the smooth converter.
The control of the evaporative cooler is closely related to the rhythm of the converter production, and its main work is in the oxygen stage of the converter. At the beginning of the converter blowing stage, the evaporator cooler inlet temperature is greater than the set value, the steam shutoff valve is opened, and after 2 seconds the steam regulator opens at 100% opening. At the same time, the jet water shutoff valve is opened, after 2 seconds, the spray water control valve is opened, and a 25% opening is set at the same time. After 12 seconds, the evaporator cooler outlet temperature is greater than the set temperature, or 35 seconds after the spray water valve is opened, the automatic adjustment procedure begins.
At the end of the converter blowing, the oxygen cut off valve closes, evaporates the cooler inlet temperature, the outlet temperature is less than the set value, the jet water shutoff valve and the control valve are closed, and after 20 seconds the jet water shutoff valve and the control valve are closed.
In order to avoid the sudden change in the temperature of the converter during the preheating of the converter, the overshoot of the blowing water caused by the sudden drop in the temperature of the oxygen blowing is controlled by the fuzzy control algorithm to reduce the system fluctuation according to the characteristics of the converter production process.