A method for ironmaking blast furnace lowering line

Abstract

The invention discloses a stock level lowering method for an iron making blast furnace. The method comprises the following steps: 1, previous preparation, to be specific, in one week before a stock level is lowered, blowing edge gas flow of coal gas flow in the blast furnace to a furnace wall and flushing to remove iron slag sticking substances unsteadily hung on the furnace wall; and 2, stock level lowering, wherein in the stock level lowering process, the oxygen enrichment use quantity is 2,500 to 3,000m<3> / h, the temperature of hot blast is higher than or equal to 1,050 DEG C, the theoretical combustion temperature in the front of a tuyere is higher than or equal to 2,500 DEG C and stock level lowering is finished when the stock level is lowered to the position of the tuyere. The method not only can flush the iron slag sticking substances hung on the furnace wall in the stock level lowering process, but also is safe and rapid.

Description

technical field [0001] The invention belongs to the technical field of blast furnace maintenance, and relates to large and medium repairs and shutting down of furnaces, treatment of furnace wall thickening, and the like. Specifically, the invention relates to a method for iron-making blast furnace feed line. Background technique [0002] Lowering line operation is a commonly used operation method for ironmaking blast furnaces to deal with nodules on the furnace wall or to shut down the furnace for overhaul. Before the operation of the lowering line, in order to maintain the smooth operation of the blast furnace and sufficient heat, the amount of coke added to the blast furnace is twice or even higher than that during normal production. During the operation of the lowering line, in order to prevent fluctuations in furnace conditions, it is generally used to stop adding oxygen enrichment and reduce the hot air temperature to 800-850°C to reduce the theoretical combustion tempe...

AI Technical Summary

Problems solved by technology

The disadvantages of this mode of operation are: 1) During the process of the material lowering line, the relative temperature of the gas distributed toward the furnace wall is relatively low and the amount of gas is small, which is not conducive to washing the slag-iron bonded on the furnace wall; 2) Due to the large local gas flow in the blast furnace, the local slag-iron bond on the furnace wall is washed away, and the falling slag-iron bond cannot be melted in time due to low temperature, which will damage the small tuyere sleeve, and in severe cases, the tuyere will explode