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High alumina refractory balls for hot blast stove

2022-09-20

Analysis of ball changing effect of hot blast stove refractory ball:

1. Reduce the resistance loss of the pebble bed

With the prolongation of the service time of the hot blast stove, the resistance loss of the pebble bed increases gradually due to the slagization of the upper corundum balls and the high-temperature bonding of the lower high alumina balls. Under the same air supply conditions, the resistance loss of the pebble bed of No. 4-2 and No. 4-3 hot blast stoves was compared and analyzed. When the cold air flow rate of No. 4 blast furnace is about 1.85×105m3/h, the mixing air regulating valve of the hot blast furnace is fully closed, the cold air pressure of No. The furnace cold air pressure is 0.330MPa, the hot air pressure is 0.320MPa, and the pebble bed resistance loss is 10kPa. By changing the balls, the air permeability of the hot blast stove pebble bed is improved, and the resistance loss is reduced. On the one hand, it is beneficial to use the ejector to enrich the coke oven gas burner; on the other hand, it is beneficial to reduce the operating power of the blower and save the power consumption. When supplying air, the current of the blower is about 711A, and when the No. 4-3 hot blast stove is used to supply air, the current of the blower drops to about 700A.

2. Changes in the furnace

Due to the slagization and agglomeration of refractory balls, most of the high-temperature flue gas passes through the edge of the large wall when the hot blast stove is fired, and the heat exchange effect of the slagging or agglomerated pebble bed in the middle is poor, and the heat storage is reduced. At the same time, due to the increase in the resistance loss of the pebble bed, the chimney and the induced draft fan are relatively insufficient, and most of the heat stays on the surface of the upper pebble bed when the furnace is fired. After the same 3 hours of burning, the temperature of the dome of No. 4-2 hot blast stove is 1284 , and the temperature of exhaust gas is 210 ; By changing the ball, the burning conditions of No. 4-3 hot blast stoves have been improved. In actual production, the No. 4-2 hot blast stove is sometimes forced to use other hot blast stoves to supply air after burning for 3 hours because the temperature of the exhaust gas is too low, and then used for air supply after 4 hours of burning. No. 4-3 hot blast stoves have good air permeability of the pebble bed. Generally, after 2.5 to 3 hours of burning the stove, the temperature of the exhaust gas rises to 350 °C, which meets the air supply requirements, and the stove is operated. For the same air supply time, after changing the ball, the burning time of No. 4-3 hot blast stove is about 1 hour shorter than that of No. 4-2 hot blast stove.

3. Changes in air supply

The air temperature changes of No. 4-2 hot blast stove and No. 4-3 hot blast stove were compared. After the No. 4-3 hot blast stove is replaced, the air mixing control valve is opened at 11% in the initial stage, and the air temperature is stable at 1198 °C. The wind temperature is 1196, and the difference between the wind temperature at the beginning and the end of the supply air is only 2. After the No. 4-2 hot blast stove is replaced, the air mixing control valve is opened by 10% at the initial stage, and the air temperature is 1202 °C. The temperature is 1175 , and the difference between the wind temperature at the initial stage and the end of the air supply is as high as 104 . By comparison, it is found that by changing the balls of the hot blast stove, the air temperature of the hot blast stove is increased by 21, and the fluctuation of the air temperature during the air supply period is reduced by 102. By changing the balls of the hot blast stove, the air temperature of the hot blast stove is obviously improved, and the large fluctuation of the air temperature during the air supply period is reduced. When the air temperature is between 1100℃~1200, the air temperature can be increased by 100, more coal can be injected by 3040kg/t, and the coke ratio can be reduced by 1520kg/t. focal ratio. At the same time, the fluctuation of air temperature has a great influence on the theoretical combustion temperature, air pressure, coal injection amount and coke load of the blast furnace. The regular ball replacement of the hot blast furnace reduces the fluctuation of the air temperature, which is beneficial to the long-term stable and forward operation of the blast furnace condition.


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