RU2285049C2 - Device for delivery of gas to reservoir - Google Patents

Abstract

FIELD: metallurgy; devices for delivery of gas to reservoirs.

SUBSTANCE: proposed device has extended passage for flow of gas; it is made in form of pipe running inside gas flowing passage from rear end to front end. Some blades are supported near end of passage by central structure; these blades are used for guide of flow and for forming vortex of hot gas escaping from passage. Wall of passage is below flow; it is cooled with water flowing through inner part of end-piece of passage. Front end of central structure on which blades rest is cooled with water delivered forward through central water passage. Cooling water is returned through central structure via circular passage.

EFFECT: enhanced resistance of device at very high surrounding temperatures.

15 cl, 9 dwg

Description

The present invention relates to a device for supplying gas to a container. It is intended, in particular, but not exclusively, for supplying a gas stream to a metallurgical vessel at high temperatures. Such a metallurgical vessel may, for example, be a melting vessel in which molten metal is produced by a direct smelting process.

The known direct smelting method, which is based on the use of a layer of molten metal as a reaction medium, and is commonly referred to in the literature as the “HIsmelt” method, is described in International Patent Application PCT / AU / 00197 (WO 96/31627) in the name of the applicant.

The HIsmelt direct smelting process described in the International Application comprises the following steps:

(a) form a bath of molten iron and slag in a vessel;

(b) is introduced into the bath:

(i) a starting material containing metal, typically metal oxides; and

(ii) a solid carbonaceous material, usually coal, which acts as a reducing agent for metal oxides and an energy source; and

(c) melting the starting material containing the metal to obtain a metal layer.

The term "smelting" in this case is understood as a designation of heat treatment in which chemical reactions of reduction of metal oxides to produce liquid metal take place.

The HIsmelt process also includes the subsequent combustion of reaction gases, such as CO and H ₂ , which are released from the bath into the space above the bath, in a gas containing oxygen, and the return of heat from the subsequent combustion to the bath to replenish thermal energy, necessary for melting raw materials containing metal.

The HIsmelt process also contains the formation of a transition zone over the nominal surface of the bath at rest, in which there is a favorable mass of rising and subsequently dropping drops or splashes, or flows of molten metal and / or slag, which create an effective environment for transferring thermal energy to the bath, obtained by subsequent combustion of the reaction gases over the bath.

In the HIsmelt process, a metal-containing starting material and solid carbon-containing material are introduced into the metal layer through a series of tuyeres / tubes that are inclined to the vertical so that they pass downward and inward through the side wall of the smelting vessel and into the lower part tanks in order to feed particles of solid material into the metal layer at the bottom of the tank. In order to stimulate the subsequent combustion of the reaction gases in the upper part of the vessel, hot blast, which can be enriched with oxygen, is introduced into the upper part of the vessel through a downward lance for supplying hot air. In order to stimulate effective subsequent combustion of gases in the upper part of the tank, it is desirable that the incoming hot blast exits the lance in the form of a swirl motion. To achieve this, external flow guides must be mounted at the output end of the lance to create a corresponding swirl motion. The upper parts of the tank can reach temperatures of the order of 2000 ° C, and hot air can be supplied to the lance at temperatures of the order of 1100-1400 ° C. The lance must therefore be able to withstand extremely high temperatures of both internal and external walls, especially at the feed end of the lance, which protrudes into the combustion zone of the tank. According to the invention, a lance design is proposed which enables internal cooling of the respective components by water and operation at very high ambient temperatures.

According to the invention, a device for supplying gas to a container, including:

a gas flow passage extending from a rear end to a front end from which gas exits the channel;

an elongated central tube-like structure extending inside the channel for gas flow from its rear end to its front end;

a plurality of flow guiding vanes arranged around a central pipe-like structure near the front end of the channel in order to create a movement with a swirl of gas flow directed towards the front end of the channel, the front end of the central structure and the front end of the channel interacting with each other so as to form an annular a nozzle for the flow of gas from the channel with a swirl, which is created by means of these blades;

cooling water passages inside the central tube-like structure so that the flow of cooling water flows forward through the central structure from its rear end to its front end, and cools this front end from the inside, and returns from there through the central structure to its rear end.

The front end of the channel can be made in the form of a hollow annular tip, and the gas flow channel can include passages for supplying cooling water to the channel tip and returning water, in order to supply cooling water forward along the channel to the channel tip and return this cooling water back along the canal.

The inner peripheral surface of the channel may be lined with refractory material.

Preferably, the central tube-like structure forms a central water flow passage so that the water flow flows forward through this structure directly to the front end of the central structure, and an annular water flow passage arranged around the central passage so that the water flow returns from the front end of the central structure back to the rear end of this structure.

The central pipe-like structure may include a central pipe that creates a central passage for water flow, and an additional pipe placed around the central pipe in order to form said annular passage for water flow between the pipes.

Preferably, the central structure includes a heat-insulating outer screen in order to delay the transfer of heat from the gas in the gas flow passage to the cooling water passages in the central structure.

The heat shield may comprise a plurality of tube-shaped segments of heat insulation material placed adjacent to each other to form a heat shield in the form of a substantially continuous pipe extending from the rear end to the front end of the central structure around an annular air gap located directly inside the heat shield.

The specified air gap can be formed between the pipe-shaped heat shield and an additional pipe forming the outer wall of the annular passage to return the water flow.

Preferably, said tube-shaped segments of the heat shield are supported to adapt to the longitudinal expansion of each segment independently of other such segments.

The front end of the central structure may include a dome-shaped protrusion part provided inside with one spiral cooling water passage in order to receive water from the central water flow passage in the central structure at the tip of the protrusion, and direct this water in a single stream around the protrusion and back along it in order to cool the protrusion with one coherent stream of cooling water.

The device may include an inlet for supplying hot gas to the rear end of the channel, the gas inlet comprising a refractory body forming a first pipe-like gas passage located on the same axis as the rear end of the channel and passing directly thereto, and a second gas-shaped pipe passage for gas across the first pass to receive hot gas and direct it into the first pass so that the hot gas and any particles carried away by it hit the refractory wall of the first pass, while the gas flow changes direction to put and from the first pass to the second pass.

The first and second passages for the gas flow can be essentially perpendicular to each other.

The central tube-like structure may extend in the center of the gas inlet means through the first and second gas flow passages and backward to a distance from the gas inlet. The rear end of the central structure may therefore be located behind the gas inlet, and may be provided with water connections for the flow of cooling water into and out of the central structure.

Below the invention is described in more detail on the example of a specific structural embodiment of the device with reference to the accompanying drawings.

Figure 1 presents a vertical section of a tank for direct smelting with two tuyeres for introducing solid particles and a tuyere for hot purging according to the invention;

figure 2 is a longitudinal section of a lance for hot purging;

figure 3 is a longitudinal section on an enlarged scale of the front of the central structure of the lance;

4 and 5 - the construction of the end of the front protrusion of the Central structure;

6 is a longitudinal section of a Central structure;

Fig.7 - plot 8 in Fig.6;

Fig.8 is a cross section along line 8-8 in Fig.7; and

Fig.9 is a cross section along the line 9-9 in Fig.7.

Figure 1 shows the tank for direct smelting, designed to carry out the process "HIsmelt" described in International patent application PCT / AU96 / 00197. The metallurgical capacity is generally indicated by 11 and has a bottom, which includes a base 12 and sides 13 formed of refractory bricks; side walls 14, which form a generally cylindrical body, which extends up the sides 13 of the hearth and which includes the upper part 15 of the housing and the lower part 16 of the housing; cover 17; outlet 18 for exhaust gases; prechamber 19 for continuous discharge of molten metal; and tap hole 21 for discharging molten slag.

In operation, the vessel comprises a bath of molten iron and slag, which includes a molten metal layer 22 and a molten slag layer 23 on a metal layer 22. The arrow indicated by 24 indicates the position of the nominal surface at rest of the metal layer 22, and the arrow indicated by 25 indicates the position of the nominal surface at rest of the slag layer 23. It is understood that the term “surface at rest” means a surface when gas and solid particles are not introduced into the container.

On the tank mounted downward lance 26 for hot blowing, in order to supply hot air to the upper part of the tank, and two lances 27 for supplying solid particles passing downward and inward through the side walls 14 and inside the slag layer 23 for feeding iron ore, solid carbonaceous material and fluxes carried away by a carrier gas depleted in oxygen to the metal layer 22. The position of the tuyeres 27 is chosen so that their output ends 28 are above the surface of the metal layer 22 during the process. This position of the tuyeres reduces the risk of an accident in contact with molten metal and also allows the tuyeres to be cooled by forced internal water cooling without significant risk that water will come into contact with the molten metal in the tank.

The design of the hot blow lance 26 is shown in FIGS. 2-9. As shown in these figures, the lance 26 contains an elongated channel 31, which serves hot gas through the inlet 32 for gas supplied to the upper part of the tank. The lance includes an elongated central tube-like structure 33, which extends inside the channel 31 for the flow of gas from its rear end to its front end. Near the front end of the channel, a row of four vanes 34 rests on the central structure 33, which create a turbulence in the gas flow exiting the channel. The front end of the central structure 33 has a domed protrusion 35 that projects forward at a distance from the tip 36 of the channel 31, so that the front end of the central body and the tip that ends the channel interact with each other to form an annular nozzle for diverging gas flow from the swirl channel created by the blades 34. The blades 34 are placed in the form of a four-helical formation and are mounted on a sliding fit inside the front end of the channel.

The wall of the main part of the channel 31, passing downstream from the gas inlet 32, is internally cooled by water. This part of the channel contains a series of three concentric steel pipes 37, 38, 39 extending into the front end part of the channel, where they are connected to the channel tip 36. The tip 36 of the channel is a hollow annular formation and has internal cooling by the water supplied and returned through the passages in the channel wall 31. Specifically, cooling water is supplied through the inlet 41 and the annular inlet branch pipe 42 into the inner annular passage 43 for the water flow formed between the pipes 38, 39 of the channel, through the hollow inner part of the tip 36 of the channel through the holes located in the circle with gaps in the tip. Water returns from the tip through openings located at a circumferentially spaced intervals into the outer annular passage 44 for returning water formed between the pipes 37, 38, and back to the water outlet 45 at the rear end of the water-cooled portion of the channel 31.

The water-cooled portion of the channel 31 is internally lined with an internal refractory lining 46, which is fitted to the innermost metal pipe 39 of the channel and passes through it to the water-cooled tip 36 of the channel. The inner periphery of the channel tip 36 is generally flush with the inner surface of the refractory lining, which forms an effective passage for gas flow through the channel. The front end of the refractory lining has a part 47 of a slightly reduced diameter, into which the swirl blades 34 enter, in a tight sliding fit. Behind part 47, the refractory lining has a slightly larger diameter to allow the central structure 33 to be inserted in the downward direction through the channel when installing the tuyere until the blades 34 creating the swirl reach the front end of the channel, where they are in tight engagement with the refractory part 47 by means of a conical refractory portion 48, which places and guides the blades inside the refractory part 47.

The front end of the central structure 33, on which the vortex blades 34 rest, is internally cooled by water that is fed forward through the central structure from the rear end to the front end of the lance, and then returns back along the central structure to the rear end of the lance. This allows a very powerful flow of cooling water to be delivered directly to the front end of the central structure and to the domed protrusion 35, in particular, which is subjected to a very high temperature flux during lance operation.

The central structure 33 comprises inner and outer concentric steel pipes 50, 51 formed by pipe segments arranged adjacent to each other and welded together. The inner pipe 50 forms a central passage 52 for water flow, through which water passes forward through the central structure from the water inlet 53 at the rear end of the tuyere to the protrusion 35 at the front end of the central structure, and an annular water return passage 54 formed between the two pipes, through which cooling water returns from the protrusion 35 back through the Central structure to the outlet 55 for water at the rear end of the lance.

The end 35 of the protrusion of the Central structure 33 contains an inner copper casing 61 mounted inside the shell 62 of the outer domed protrusion, also made of copper. The inner copper body 61 has a central passage 63 for the flow of water received from the central passage 52 of the structure 33 and directed to the tip of the protrusion. The end of the protrusion 35 is provided with protruding ribs 64 which are tightly fitted into the protrusion shell 62 in order to form one continuous passage 65 for the flow of cooling water between the inner part 61 and the outer protrusion shell 62. This is especially clearly seen in FIGS. 4 and 5. The ribs 64 are shaped so that a single continuous passage 65 is formed in the form of ring segments 66 interconnected by segments 67 having an inclination from one ring segment to the next.

Thus, the passage 65 extends from the tip of the protrusion in the form of a spiral, which, although not a regular spiral formation, forms a spiral around the protrusion and back along it, until it exits at the rear end of the protrusion inside the annular passage for return formed between the pipes 51, 52 central design 33.

The forced flow of cooling water in the form of a single coherent flow through a spiral passage 65 passing around the end 35 of the protrusion of the Central structure and back along it, provides effective heat dissipation and eliminates the formation of "hot spots" on the protrusion, which can occur if it is possible to separate the cooling water on separate streams at the ledge. In the apparatus shown, cooling water is limited to one stream from the moment when it enters the end of the protrusion 35 to the moment when it exits from the end of the protrusion.

The inner structure 33 is provided with an external heat shield 69 reflecting the heat transferred from the hot gas stream entering the channel 31 to the cooling water passing inside the central structure 33. In the case of exposure to very high temperatures and high gas flow rates required in a large melting plant scale, a solid refractory screen can have only a short service life. In the structure shown in the drawing, the screen 69 is formed of tubular bushings made of ceramic material, which is commercially available under the name UMCO. These sleeves are located close to each other to form a continuous ceramic screen surrounding the air gap 70 between the screen and the outermost pipe 51 of the Central structure. In particular, the screen can be made of tube-shaped segments of UMCO 50, which contains in wt.% From 0.05 to 0.12% carbon, from 0.5 to 1% silicon, a maximum of 0.5 to 1% manganese, 0.02% phosphorus, 0.02% sulfur, from 27 to 29% chromium, from 48 to 52% cobalt, the rest is mainly iron. This material provides effective heat-shielding, but it is subject to significant thermal expansion at high temperatures. To solve this problem, individual tube-shaped segments of the heat shield are formed and mounted, as shown in FIGS. 6-9, to enable them to expand in the longitudinal direction independently of each other, while the screen remains essentially continuous all the time. As shown in these figures, individual bushings are mounted on the fixing strips 71 and the support plates 72 fitted to the outer pipe 51 of the central structure 33, the rear end of each screen pipe having a step 73 in order to fit it to the support plate with a gap 74 at the end to allow independent longitudinal heat-shielding expansion of each strip. The anti-rotation strips 75 can also be mounted on each sleeve to fit them to one of the locking strips 71 on the pipe 52 to prevent rotation of the screen sleeves.

Hot gas enters the channel 31 through the gas inlet 32. The hot gas may be oxygen enriched air entering through heating furnaces at a temperature of about 1200 ° C. This air is supplied through a piping system with a refractory lining, and it traps the refractory powder, which can cause severe erosion problems if it enters at a high speed directly into the main water-cooled portion of the duct 31. The gas inlet 32 is designed to be fed into the duct large volumes of hot air with refractory particles, and at the same time, to minimize damage to the water-cooled part of the channel. The channel 31 is formed by a T-shaped housing 81, molded in the form of a block of wear-resistant refractory material and placed inside a thin-walled outer metal shell 82. The housing 81 forms a first tube-shaped passage 83 located on the same axis as the central passage of the channel 31, and a second pipe-shaped passage 84, perpendicular to the passage 83, in order to receive a stream of hot air from furnaces (not shown). The passage 83 is located on the same axis as the gas flow passage of the channel 31 and is connected to it through the central passage 85 in the refractory connecting part 86 of the inlet 32.

Hot air supplied to the inlet 32 passes through a pipe-shaped passage 84 of the housing 81 and hits the wear-resistant refractory wall of the thick refractory housing 82, which is resistant to erosion. Then the gas flow changes direction and passes at right angles in the downward direction through the passage 83 of the housing 81 of the T-shape and the central passage 85 of the transition part 86, and into the main part of the channel. The wall of the passage 83 can be tapered in the forward direction of the flow in order to accelerate the flow in the channel. It can, for example, be reduced to a cone with an included angle of the order of 7 °. The thickness of the transition refractory body 86 is tapered to fit it to the thick wall of the refractory body 81 at one end and to a much thinner refractory lining 48 of the main part of the channel 31. It also accordingly has water cooling by means of an annular cooling water jacket 87 through which the cooling water circulates from inlet 88 to outlet 89. The rear end of the central structure 33 passes through a pipe-shaped passage 83 of the gas inlet 32. It is placed inside the plug 91 of the refractory lining, which closes the rear end of the passage 83, and the rear end of the Central structure 33 extends back from the gas inlet 32 to the water inlet 53 and the outlet 55.

Using the device shown, large volumes of hot gas can be introduced into the tank 26 for melting at high temperature. The central structure 33 can supply large volumes of cooling water quickly and directly to a portion of the protrusion of the central structure, and the forced flow of this cooling water, in the form of an undivided cooling stream around the protrusion structure, allows very efficient heat removal from the front end of the central structure. An independent flow of water to the channel tip also enables efficient heat removal from other lance components that are highly flux-heated. The flow of hot air into the inlet, in which it hits the thick wall of the refractory chamber or passage, before going down to the channel, allows you to process large volumes of air contaminated with refractory powder, without severe erosion of the refractory lining and heat shield in the main part of the lance .

Claims (15)

1. A device for supplying gas to a container, including a channel for a gas stream passing from its rear end to the front end, from which gas exits the channel, an elongated central tube-like structure passing inside the channel for gas flow from its rear end to its front end , a plurality of flow guiding vanes arranged around a central tube-like structure near the front end of the channel in order to create a swirl motion of the gas flow directed towards the front end of the channel, the front to the end of the central structure and the front end of the channel together form an annular nozzle for discharging the gas flow from the channel with a swirl created by the blades, cooling water passages inside the central tube-shaped structure so that the cooling water flow passes forward through the central structure from its rear end to its the front end and cooled from the inside this front end and returned from there back through the central structure to its rear end. 2. The device according to claim 1, in which the front end of the channel is made in the form of a hollow annular tip, and the channel for gas flow includes passages for supplying cooling water to the channel tip and returning water from it in order to supply cooling water forward along channel into the channel tip and return this cooling water back along the channel. 3. The device according to any one of claim 1 or 2, in which the inner peripheral surface of the channel is lined with refractory material. 4. The device according to any one of claims 1 to 3, in which the Central tube-like structure forms a Central passage for the flow of water so that the water flow passes forward through this structure directly to the front end of the Central structure, and an annular passage for water flow, placed around the central passage so that the water flow returns from the front end of the central structure back to the rear end of this structure. 5. The device according to claim 4, in which the central pipe-like structure comprises a central pipe, which creates a Central passage for the flow of water, and an additional pipe placed around the Central pipe in order to form an annular passage for the flow of water between the pipes. 6. The device according to any one of claims 1 to 5, in which the central structure includes a heat-insulating outer screen that delays the transfer of heat from gas in the gas flow channel to the cooling water passages in the central structure. 7. The device according to claim 6, in which the heat-insulating screen comprises a plurality of tube-shaped segments of heat-insulating material placed close to each other to form a heat-shielding screen in the form of a substantially continuous pipe extending from the rear end to the front end of the central structure around the annular air gap, formed directly inside the heat shield. 8. The device according to claim 7, in which the specified air gap is formed between a tube-shaped heat shield and an additional pipe forming the outer wall of the annular passage to return the water flow. 9. The device according to any one of claims 7 to 8, wherein said tube-shaped segments of the heat shield are supported to adapt to the longitudinal expansion of each segment independently of other such segments. 10. The device according to any one of claims 1 to 9, in which the front end of the Central structure includes a portion in the form of a domed protrusion, provided inside with one spiral passage for cooling water in order to receive water from the Central passage for water flow in the Central structure at the tip protrusion and direct this water in a single stream around the protrusion and back along it in order to cool the protrusion with a single coherent stream of cooling water. 11. The device according to any one of claims 1 to 10, which is equipped with an input for supplying hot gas to the rear end of the channel, the gas inlet comprising a refractory body forming a first pipe-like gas passage located on the same axis as the rear end of the channel and passing straight to it, and a second tube-shaped gas passage, located across the first passage, to receive hot gas and direct it into the first passage so that the hot gas and any particles carried away by it hit the refractory wall of the first passage, and the gas flow changes Changes the direction on the way from the first pass to the second pass. 12. The device according to claim 11, in which the first and second passages for the gas flow are essentially perpendicular to each other. 13. The device according to any one of paragraphs.11-12, in which the Central tube-like structure passes in the center through the first passage for the flow of incoming gas and back to the distance from the inlet for gas. 14. The device according to item 13, in which the rear end of the Central structure is located behind the gas inlet and is provided with connections for the flow of cooling water into and out of the Central structure. 15. A metallurgical vessel equipped with a device for supplying a gas stream to the upper part of the vessel at high temperatures, said device being made in accordance with any one of claims 1-14 and mounted on the lid of the vessel so that it passes down through the lid, the back the end of the channel for gas flow is placed above the lid and the front end of the channel is located in the upper part of the tank.

Images