The blast furnace hot furnace has evolved from the earliest internal combustion and external hot air furnace to the current top -fire hot furnace. After more than 20 years of development, the top combustion hot air furnace has achieved large -scale, efficient, longevity, and has achieved it. The remarkable technical achievements, with the large -scale and high wind temperature development of the top -burning hot air furnace, steel companies have also put forward higher requirements for the air supply temperature of the hot air furnace. At this time The recognition of various steel companies, because the characteristics of silicon brick heat furnaces are different from traditional low creep and hot air furnaces and red pillars hot air furnaces, the oven operation requirements of silica brick hot furnaces are higher than other materials. The correct oven operation of silica brick hot furnace:
Silicon brick hot furnace baking curve
Due to the differentiation of furnace capacity in the hot air furnace, the general oven period is controlled between 20-45 days (formulated according to the adjustment of the furnace), which is usually divided into four stages:
1. Keep 9-20 days below 300 ° C. The purpose is to eliminate the attachment water after silicon brick masonry. At the same time, it also takes into account the conversion of phosphorus and square quartz. The changing temperature of the phosphorus is 110-160 ° C, the volume change is 0.2 -0.28%; the change temperature of the square quartz is 170-270 ° C, and the volume change is about 3.0%.
2. Keep 6-15 days between 300-600 ° C. During this period, the depth of water after the masonry was continued. This temperature interval has the transformation of β square quartz to alpha squares, accompanied by a large volume expansion, which This interval is to maintain a longer slow temperature time to reduce the temperature difference in the thickness direction of the silicon brick and avoid damage to the lining material.
3. Keep 3-7 days between 600-800 ° C, and the β-square quartz that may remain in the silica bricks is completely transformed into α square quartz, with a volume change of 0.82%. , Make SIO2 complete the transformation of the crystal.
4. Keep it between 800-1000 ° C for 2-3 days, so that the hot air furnace can be further baked, and the temperature continues to increase to the level required for the blast furnace.
Enter the oven operation
1. ignition operation. Confirm that all the valves of the three hot air furnaces are completed, open the flue valve slightly, put the firewood in advance in the 3 hot air furnaces, and ignite in the order of 1#, 2#, and 3#one by one. Bake in mixed gas at the gun.
2. Bake the oven curve. It is always necessary to control the temperature of the vault temperature, and refer to the temperature of the exhaust gas to compare and analyze the actual overturge curve of the plan. It should be noted that when the fire refractory material is large and small, the chimney pumping force is small in the early stage, the flame of the mixed gas burner is extremely unstable and it is difficult to control. It should be observed closely. Once the flame is turned off, the mixed gas and air pressure wind should be turned off. Repel the ignition in time.
In the early stage of the oven, the bakers with φ25mm and φ50mm were baked. The temperature was easy to control and stable, and it could meet the demand for heating below 500 ° C. When the bakery could not meet the heating demand, the specially designed mixed gas burning mouth continued to rise. When the temperature is close to the range of silicon brick (600-700 ° C), the temperature should be stabilized for a period of time. Try to avoid fluctuations up and down. After the temperature is transformed, the heating speed can be faster.
Precautions for temperature adjustment:
1. The actual air and gas volume should be adjusted according to the oven curve, and the air flow is adjusted every 4h;
2. When regulating the combustion air flow, you need to carefully adjust the gas flow according to the architution of the vault;
3. After the oven, the exhaust gas temperature should be between 100-400 ° C. If the actual temperature exceeds this range, the proportion of air and gas flow should be adjusted to ensure that the vault temperature meets the required temperature.
4. During the oven period, the hot air furnace needs low positive pressure (10mm water column) to prevent the inhaling air from rising the temperature of the exhaust gas.
