SU1713940A1 - Bottom tuyere - Google Patents

Description

The invention relates to metallurgy, in particular to converters with bottom and combined purge.

Known tuyere for bottom blowing of the melt containing the inner pipe and wrapping it around the outer pipe, forming slit-like cavities for supplying oxygen and protective gas.

A tuyere for bottom metal blowing is also known, consisting of coaxially arranged pipes, the working part, tuyeres consisting of several oxygen nozzles built into a porous refractory block through which protective gas is supplied: \ in turn, the entire block with nozzles at the tuyere section is surrounded along the contour with an annular gap for supplying protective gas.

A lance is known, the embodiment of which has a central nozzle for under-. aci oxidizing gas and four peripheral pipes with round bars and channels between them.

Also known is a bottom tuyere made in the form of a single central tuyere containing in the common housing a block of cylindrical nozzles for supplying oxygen or neutral gas, between which protective gas is supplied. A central distributor in the form of a diffuser is used to supply the working gas to the nozzles. The main disadvantages of the known tuyeres are the central location of a single tuyere, which limits the zone of blast effect on liquid metal: the location of the nozzles in a limited volume of the tuyere body causes the nozzle gas flows to merge into a single stream (sheaf), equivalent in effect to a concentrated source of energy supply to the melt, which leads to , i wave formation on the surface of the bathtub and hydraulic shocks that destroy the lining in the nozzle region, and subsequently lead to burnout of the exposed tuyeres: unequal Vai durability nozzles

1713940 A1 tuyeres due to the uneven temperature field for nozzles located in the central part of the tuyere and on the periphery of the tuyere; the complexity of the design, having (not counting nozzles and standard products) 5 more than ten parts that require machining.

The purpose of the invention is to increase the service life of the lance and simplify the design.

This goal is achieved by the fact that the bottom 10 lance is made in the form of a nozzle block for the separate supply of reagents and shielding gas, moreover, nozzles for supplying the shielding gas are placed coaxially with a gap around the nozzles for supplying reagents, all nozzles 15 are installed in a row adjacent to each other and have a ratio of the total working cross-sectional area of the gas channels to ^ the total cross-sectional area of the channels for supplying reagents 0.25-0.5. The tuyere nozzles in a 20 • cross section may also form a symmetrical shape. Such tuyere design allows multiple tuyeres over a substantial area of the bottom of the converter and thereby disperse WHO-25 action for the entire gas volume of the bath, since the blast energy dissipation in the melt increases proportionally relative bstr / A horse (wherein dcrp - jet diameter; O _to NVG Bath diameter). For a linear system, the characteristic linear size, which determines the processes of heat and mass transfer in the bath, has been determined to be the length L. block nozzles in cross section, and the dispersion energy is determined by parameter 35 L / Dkohb. Since 1 _ »<1 pp, the energy dissipated by the tuyere increases significantly, which leads to a decrease in wave formation and a decrease in hydraulic shocks in

- the bottom of the converter, increasing the service life of 40 lances; an increase in the dispersion of the flow is facilitated by the imposition of pulsations; the process efficiency is determined by the ratio of the total area of gas channels to the total area of 45 channels for supplying reagents in the range 0.25-0.5; linearly located tuyere nozzles are in the same temperature conditions. which contributes to their uniform wear: the construction of the lance 50 is simple, except for two identical connecting flanges (actually one part), made of standard pipes, sheet metal, does not need machining. 55

In FIG. 1 shows a frontal pro. Lance projection in the form of a packet of nozzles united by a perforated plate panel. in a local section, part of the panel is removed, a longitudinal section through nozzles; in FIG. 2 is a cross-sectional view of the lance shown in FIG. 1; in FIG. 3-6 — various cross-sectional shapes of the tuyere with ovoid outer tubes of peripheral nozzles (section AA in FIG. 1).

The tuyere consists of coaxial nozzles 1 with an annular gap made of outer pipes 2 and inner 3. The constancy of the annular gaps between the pipes is provided by inserts 4. The tuyere nozzles are connected by contact welding with perforated panels 5, forming a block having a manifold 6 for oxygen supply and collector 7 for supplying a protective gas. The lance assembled in the block is installed in the wells of the lining of the converter bottom with the nozzles upward so that the collectors 6 and 7 are located on the outside of the bottom. The space between the tuyere block and the walls of the well is filled with a refractory mass and compacted. The holes in the panel facilitate filling a mass of voids and the formation of a single gas-tight monolith of the bottom after drying the lining.

Tuyere works as follows.

Oxygen through the collector 6 enters the inner tubes 3 of the coaxial nozzles 1, and the pulsating protective gas through the collector 7 - into the lance: into the annular gaps of the central nozzles 1 and peripheral nozzles (the main version) or the gaps of the peripheral nozzles with ovoid outer tubes (options). The behavior of the jets of oxygen flowing out of the central nozzles is characterized by an alternating state as they are removed into the melt: a flooded stream - a shock wave - an emulsion zone. The formation of compression shocks caused by the deceleration of a supersonic gas flow is accompanied by thermal shocks caused by intense heat generation in the reaction zone. The shielding gas flowing from the central annular nozzles 1 is not miscible with oxygen. and after heating to 900-1000 ° C decomposes with heat absorption, contributing to the cooling of the nozzle mouths. This small flow of shielding gas is not able to significantly affect the reaction zone. The main effect on the hydrodynamic imbalance that causes non-stationary periodic processes is exerted by the high-temperature primary reaction zone, the volume of which periodically varies 4-10 times. Back impacts at the nozzle exit of the tuyere and tuyere zone occur when the bubbles collapse or large gas-liquid volumes detach due to the thermomechanical effect of iron oxides having a temperature

1713940 6

2200-2700¾. At the same time, an oscillating bulge forms on the surface of the bath, which is a source of waves. Closely located jets of a gas-metal emulsion in the melt from the central nozzles interfere, forming a jet equivalent to a slot. To enhance the effect of crushing the jet, the effect of shielding gas jets coming from peripheral nozzles or increased through the use of tubes of a special shape (ovoid) of the gaps of the peripheral nozzles is also used.

Claims (2)

Claim 1. A bottom tuyere containing a block of nozzles for supplying reagents and nozzles for supplying shielding gas, characterized in that, in order to increase the service life, it is additionally equipped with nozzles for supplying shielding gas, each of which is placed coaxially with the nozzle for supplying reagents with the formation gap and installed in a row ^. adjacency to each other, the ratio of the total area of the gaps to the total area of the nozzles for supplying reagents is 0.25-0.5. 2. A tuyere according to claim 1, characterized in that the tuyere nozzles in the cross section are installed to form a symmetrical figure. . Order 661 Circulation Subscription VNIIIPI of the State Committee for Inventions and Discoveries under the State Committee for Science and Technology of the USSR 113035, Moscow, Zh-35, Raushskaya nab., 4/5 < Production and Publishing Combine Patent, Uzhgorod, 101 Gagarin St.