SU817055A1 - Blasting tuyere of blast furnace - Google Patents

Description

one

The invention relates to ferrous metallurgy, in particular, to equipment for supplying hot blast to a blast furnace.

The cooled lance of the blast furnace is known, consisting of a body in the form of external and internal cups, coke, lanz, a supply of 1C and piping of the cooling agent, various devices, devices inside the cooled cavity flj. .

However, in the known lance, heat transfer intensification is achieved due to high cooling rates, usually not less than 8 m / s, which is associated with the use of powerful high-pressure pumps.

Closest to the proposed technical essence and the achieved result is the blast tuyere of the blast furnace, comprising a housing in the form of external and internal cups, a toe cap, a flange, a chamber located inside the housing, supplying and discharging cooling agent G2.

The disadvantages of the tuyere - the uneven distribution of the cooling agent

cross-section of annular channels; insufficient circulation of the cooling agent in the inner chamber; insufficient heat removal in the most heat-stressed front of the lance, all this impairs the heat exchange in the lance and reduces its durability.

The purpose of the invention is to increase the durability of the tuyere.

0

This goal is achieved by installing an annular nozzle on the front of the chamber and a chamber located coaxially inside the chamber, as well as tangentially connecting the pipe for

5 coolant supply with camera.

The annular nozzle is designed to intensify heat transfer in the most highly stressed front end.

0 tuyeres due to the formation of a turbulized jet directed at the nose of the tuyere. Mirin nozzle exit slit refers to the thickness of the annular channels between the chamber

5 and the hull within Оj 5-2.0.

In tab. i shows the results of choosing the optimal size of the nozzle exit slit.

Indicators

Coolant speed:

in the annular channels between the chamber and the lance body, m / s

in the exit section of the nozzle, m / s

The hydraulic resistance of the nozzle, n / m Reynolds criterion

Heat transfer coefficient:

in the annular channels between the chamber and the body of the fourka

M in the nose of the tuyere. Reducing the number of nozzles less than 0, 5 is impractical due to an increase in the hydraulic resistance of the nozzle by more than 1000 n / m and an increase in the likelihood of clogging of the nozzle with scale or other mechanical impurities. An increase in the slit width of the nozzle exit section of more than 2.0 is irrational due to a decrease in the speed of the hlascagent at the exit of the nozzle to a smaller value than the tuyere body in the channels between the chamber. In this case, the heat transfer rate in the nose of the tuyere compared with that of the tuyere. the hull is also reduced, which leads to a decrease in the resistance of the Lurma. Since the inner surface of the lance of the tuyere is toroidal, from the point of heat transfer and hydraulic resistance ijypMH, the nozzle face distance from the inner wall of the tuyere is equal to half the distance between its inner and outer stacks. the bow. However, due to the insignificant effect on the heat exchange and the hydraulic resistance of the tuyere, changing the location of the nozzle face within certain limits, the minimum and maximum distance of the nozzle face from the inner wall of the tuyere is equal, respectively, to the thickness of the annular channels between the chamber and the stacker of the tuyere and the distance between the inner and outer cups in the nasal part. The insert is designed to reduce the cross-sectional area of the chamber. It divides the chamber into two inner annular channels equally. Table 1

The ratio of the width of the slit nozzle to the thickness of the annular channels between the chamber and the body of the tuyere

less than 0.5

0.5-2.0

more than 2

0,70,7

1.6 1.4-0.7 Less than 0.7

100 1000-250M-; her 250

7860 7860-7960More than 7950

170017003400 3400-1700More than 1700 howling width. The width of the channels is determined from the condition that they provide speed of at least 0.7 m / s. At these speeds, there is no loss of mechanical impurities from the refrigerant and a sufficiently intense heat removal from the outer channels occurs, especially effective when liquid iron enters the tuyere and a vapor film is formed in the outer annular channel. The tangential connection of the supply line, where the refrigerant of the pipe to the chamber makes it possible to obtain a uniform distribution of the cooling agent. Over the cross section of the chamber. The angle of the axis supplying the refrigerant pipe and the rear wall of the chamber at the point of their connection is 5-30. If the angle is less than 5, there are structural difficulties in making the connection. When coal is more than 30, there is a significant deterioration in the distribution of the refrigerant in the chamber. The distance from the chamber to the Lurma slang is equal to 1.03, 0 of the diameter of the pipe supplying the refrigerant, the reduction of this distance less than 1.0 is impossible for constructive reasons. Increasing this distance more than 3, O causes a deterioration in the cooling of the tuyere body. FIG. 1 depicts a lance, a general view; in FIG. 2 - section A-Anafig. one; in fig. 3 shows a section BB in FIG. 2, the lance contains a flange 1, a housing in the form of an outer 2 and an inner 3 cup, a knife part 4, pipes 5 and 6 for supplying and discharging a cooling agent, inside the cooled cavity of the Lurma there is a chamber 7 fixed to the coolant supply pipe and supports 8 . An annular nozzle 9 is fixed on the front of the chamber,

and the insert 11 is coaxially mounted inside the chamber on the supports 10.

Outer annular channels are formed between the chamber and the tuyere body along which the cooling agent moves. The channels have the same width, equal to 4-10 mm. The nasal part of the tuyere has a toroidal cooled surface.

The cooling agent through the tangential tube enters the chamber, then. moves through the channels inside the chamber and exits through the annular nozzle, cooling the tuyere toe. Further, the coolant flow is divided along the outer channels, cools the body of the tuyere, and their cooled cavity is removed through the discharge pipe.

The results of testing the resistance of the model in the flow of liquid iron

The lance can have a heat-resistant protective layer deposited on the working surface by spraying or a heat shield lining.

The fuel supply to the lance can be carried out either through a flange or through a water-cooled cavity into the inner cup.

In the process of testing the model of a tuyere without a protective coating, it was established that its durability in the flow of molten iron is provided at cooling agent speeds. And in the outlet section of the nozzle and in the outer channels of the tuyere, 0.8 m / s and 0.5 m / s, respectively (see Table 2).

Table 2

Movement speed

water:

in the exit section of the nozzle, m / s

in the outer annular channel, m / s

Duration of immersion of the model in liquid iron, min

Specific heat flow, mW / m

The thickness of the formed skull, mm 0,5

Res-VEZ-without damage-damage-institutes SRI

The use of the proposed tuyere allows to reduce downtime of blast furnaces to replace burnt tuyeres, reduce disturbances in the blast furnace process, increase the productivity of blast furnaces and reduce the cost of iron.

Claims (2)

1. Aidonev SM and others. Cooling blast furnaces. M., Metallurgists, 1972, p. 278.. 2. The patent of Germany 1533845, 65 KL-. 18 A 7/16, published. 1972. SS