Reasons for Blast Furnace Tuyere Burning Loss

1.Furnace Condition is Unstable and the Hearth is Piled Up
Such a situation is often encountered in production. The blast furnace condition has been fluctuating greatly, the stability is very poor, and the air is frequently added and subtracted, and the long-term stability of the blast furnace cannot be achieved. Due to the frequent air reduction operation of the blast furnace and the unplanned air suspension for a long time due to the external influence, the hearth is inactive and piled up, the generated slag and iron cannot penetrate into the hearth in time, and the circulation of molten iron at the accumulation part is not smooth, resulting in slag and iron in front of the tuyere. Aggregation can easily cause the tuyere to burn.
2.Influence of Decrease in Liquid Permeability of Dead Coke Stack
After the liquid permeability of the dead coke pile in the hearth decreases, the slag and iron falling in the dripping belt cannot penetrate to the bottom of the hearth through the dead coke pile quickly, and the slag iron is easy to accumulate at the front end of the tuyere. The bad position is in the lower part. One of the main reasons is that the metallurgical properties of coke are poor, so that the coke particle size of the dead coke pile in the furnace is small, resulting in a decrease in the liquid permeability of the dead coke pile.
3.The tuyere cover is upturned
Another reason for the serious burning loss of blast furnace tuyere is that the tuyere sleeve is upturned. Alkali metals and zinc in the blast furnace charge can cause poor strength, volume expansion and plastic expansion of carbon bricks, resulting in upturning of the middle sleeve. Because the tuyere is upturned, it has a great influence on the distribution of the initial gas flow. The initial gas flow enters the tuyere and then goes upwards instead of downwards, which leads to inactive hearth and accumulation.
4.Wear of the air vent
The front end of the tuyere protrudes into the hearth, and wear is caused by the friction of the injected pulverized coal and the scouring of the high-speed moving material in the tuyere whirling area. The wear parts are generally on the left and right sides of the horizontal centerline plane of the tuyere sleeve.
5.Effects of rehab
When the blast furnace is in normal production, it behaves normally. When the blast furnace is suspended or re-aired after the furnace is reheated, a large number of tuyere burns appear, which delays the blast furnace re-air process. For this phenomenon, it often leads us into the misunderstanding of the serious accumulation of the hearth, thinking that it is caused by the heavy accumulation of the hearth. After all, the accumulation of the hearth is an important reason for the burning of the tuyere. It is also believed that the opening of the tuyere is too fast, and the originally blocked tuyere area is not sufficiently active, so that the slag and iron produced after being opened cannot smoothly penetrate into the hearth and burn the tuyere.
6.Charging system is too marginal
Considering the long time off for blast furnace, the charging system has been adjusted accordingly; the production practice after rewinding proves that the charging system is too developed to the edge, resulting in a decrease in the utilization rate of gas and the direct reduction degree of the blast furnace. increase, which affects the fluidity and smelting performance of slag and iron; the excessive development of the charging system at the edge is a factor for the subsequent tuyere burning loss.

Post time: Sep-05-2022