SU635135A1 - Method of stopping blast furnaces - Google Patents

Description

one

The invention relates to the field of ferrous metallurgy, in particular to methods of stopping the furnace for the replacement of a charging apparatus.

The closest to the invention but technical essence and achievable results is the method of stopping blast furnace for replacing the charging unit with lowering the charge, in which the stopping is performed after removing all melting products from the furnace, i.e. immediately after the release of the cast iron {1.

In this case, a significant amount of heat is removed from the furnace with liquid smelting products. To compensate for the heat loss and ensure the normal start-up of the blast furnace after repairs on the last day of its work, 5–8 idle feeds are loaded into the furnace, so that by the time the lightweight truck stops, the lightweight mixture reaches the level of the tuyeres.

However, according to a known method, during the start-up period, it is not possible to fully compensate for heat loss due to the additional consumption of coke and the start-up of the blast furnace is carried out in the absence of heat.

In addition, the blast furnace start-up was carried out at a fixed charge. In connection with this, in the starting period the cast iron is chemically cold2

pny, low-basic, viscous and low-volatile slags.

All this hampers the release of smelting products, increases the labor intensity of mining operations, which hinders an intense expansion and reduces the blast furnace output. As a result, the start-up period, i.e., the time for which the blast furnace is outputted to its normal operating parameters, is increasing and is practically 50-60 hours. It is not possible to force the operation of the furnace during this period.

The purpose of the invention is the ecoiomi of coke and the reduction of the ieriod of the subsequent blow.

The goal is achieved by the proposed method for stopping the blast furnace, which includes lowering the blast furnace at a set-point level and gas ignition at the furnace top, stopping the furnace is performed 1.5-2.0 hours after the production of pig iron with the treatment of the upper slag.

This ensures the accumulation of the optimal safe quantity of smelting products in the furnace of the blast furnace, which remains during the repair period, which allows to accumulate in the furnace the amount of heat that is necessary for the normal start of the blast furnace and its repair without additional consumption of coke.

Due to the fact that the charge is not lightened, slags during the starting period have normal basicity, their release and mining operations are facilitated. All this allows to speed up the start-up of the blast furnace and reduce the time of its departure to normal operating parameters by 2-3 times.

This method is carried out as follows.

In the preset period, the furnace operates on a charge with a normal working ore load. The latest release of cast iron is made 1.5-2.0 hours before stopping the nechi.

In the planned period of production, lowering the charge to a predetermined level and, when the desired charge level is reached, the furnace is transferred to pressure to blow 0.1 MPa, after which the valve is closed on the gas pipeline of the valve, and the candles are opened to the furnace. On the small and large cones there should be no charge. A small cone is opened and both cones are supplied with steam. At the same time, the filling valves must be closed and the exhaust valves open. Then open the hatches on the gas shutter and the nodal holders. After that, gas is ignited at a small blast at the gas gate, and after the steady burning of gas, the blast is completely stopped, the tuyeres are clogged with clay. After the tuyeres are closed with clay, the furnace is loaded with slag. With steady gas burning in the furnace, the nozzles are removed and the tuyeres are carefully lined with clay, then the work associated with the ventilation of the gas path of the furnace is performed and the filling apparatus is replaced.

The furnace is started up with hot blast with a temperature of 500-700 ° C with minimal positive pressure with a gradual increase to normal operating parameters. In this case, the first release of cast iron

produced after 2.0-2.5 hours from the beginning of the furnace start-up.

After the release of cast iron, natural gas is supplied to the furnace in the amount of 4-5% to the blast, 5 gradually over 5-6 hours, increasing its quantity to the operating limits.

The second and subsequent releases of iron are produced according to the release schedule.

According to the proposed method, the furnace outputs 0 to normal operating parameters in 18-20 hours. At the same time, for a normal furnace start-up no additional coke consumption is required, the productivity of the blast furnace during the start-up period increases, and mining operations during the start-up period, as the melted products well heated and mobile.

Using the proposed method of stopping a blast furnace for the replacement of an apparatus provides the following advantages over existing methods.

The output of the furnace to the normal operating mode was carried out in 18-20 hours instead of 3-4 days according to the previously adopted technology and the production increased by 1000-2000 tons of pig iron for each repair; Coke saving reaches 100-150 tons per stove stoves for the replacement of the charging unit.

Claims (1)

Invention Formula The method of stopping blast furnaces with lowering the charge and igniting the gas at the furnace top, characterized in that, in order to save coke and shorten the period of subsequent expansion, the furnace is stopped 1.5-2 hours after the production of pig iron and mining of the upper slag. Sources of information taken into account in the examination 1. Typical technological instructions for domain production. USSR Academy of Medical Sciences, Dnepropetrovsk, 1967.