CN110592301B - A blast furnace with oxygen-enriched coal injection tuyere and smelting process - Google Patents

Abstract

The invention belongs to the technical field of metallurgical equipment, and particularly relates to a blast furnace with an oxygen-enriched coal injection tuyere and a smelting process. The invention provides a blast furnace with an oxygen-enriched coal injection tuyere, which comprises a furnace cover, a furnace body, a furnace belly and a furnace hearth which are sequentially arranged, and a blast furnace tuyere between the furnace belly and the furnace hearth, wherein the blast furnace tuyere comprises a large sleeve, a middle sleeve and a small sleeve which are arranged on the furnace wall of the furnace belly; a cooler is sleeved outside the blowpipe, the inner cavity of the cooler is filled with cooling water, and a plurality of uniformly arranged fins are arranged on the side wall of the cooler; a coil pipe is arranged between the small sleeve and the outer wall of the cooler, and the coil pipe is filled with air at normal temperature and connected with an air pump. The invention forms a structure that the middle sleeve is cooled by water cooling, the small sleeve is cooled by air cooling, and the outer side of the blowpipe at the central position is cooled by water cooling through the three layers of circulating cooling systems arranged in the tuyere, thereby realizing the purposes that the tuyere of the blast furnace can resist high temperature and thermal fatigue, overcome abrasive particle erosion and prolong the service life.

Description

A blast furnace with oxygen-enriched coal injection tuyere and smelting process

technical field

The invention belongs to the technical field of metallurgical equipment, and in particular relates to a blast furnace with an oxygen-enriched coal injection tuyere and a smelting process.

Background technique

The smelting of the iron and steel industry is a process in which the charge is loaded from the top of the blast furnace into the furnace for smelting to obtain steel, in which the setting and structure of the tuyere are one of the key components. It not only directly provides the oxygen and pulverized coal required for blast furnace smelting, but also provides the gas power required to overcome the resistance of the blast furnace column, and transmits the high temperature gas such as oxygen and pulverized coal to the blast furnace. Therefore, the blast furnace tuyere should have the characteristics of good conductivity, uniform cooling, high cooling efficiency, dense structure, and good wear resistance. It is usually installed in the furnace wall between the furnace belly and the furnace bottom. The front section has a 500mm extension into the furnace, which is directly affected by the thermal erosion of the liquid slag iron and the serious wear of the falling hot material, which is easy to fail. Frequent replacement of the tuyere will cause The blast furnace shutdown will lead to low blast furnace output.

The operating environment of blast furnace tuyere is extremely harsh. It not only has to withstand high temperatures above 1500°C, but also bears the erosion of high-temperature iron flow and the wear of charge and slag. 150 m/s and containing pulverized coal) and other harsh environments, so the service life is short.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned technical problems, the present invention provides a blast furnace with an oxygen-enriched coal injection tuyere. Through the three-layer circulating cooling circulation system set at the tuyere, the middle jacket is water-cooled, the small jacket is air-cooled, and the center is cooled. The cooling structure of water cooling on the outside of the blowing pipe realizes the purpose that the blast furnace tuyere can withstand high temperature, heat fatigue, overcome abrasive erosion, and prolong the service life.

In order to achieve the above purpose of the invention, the present invention provides a blast furnace with an oxygen-enriched coal injection tuyere, which includes a furnace hood, a furnace body, a furnace bolly and a hearth that are sequentially arranged from top to bottom, and the furnace body is provided with gas nozzles. , the hearth is provided with a slag outlet, the blast furnace tuyere between the hearth and the hearth, the blast furnace tuyere includes a large sleeve arranged on the furnace wall of the hearth, and the large sleeve is sleeved with a middle sleeve , the middle sleeve is provided with a small sleeve, the central position of the small sleeve is provided with a blowing pipe, and the inside of the middle sleeve is provided with a first water jacket;

A desuperheater is sheathed on the outside of the blowing pipe, the inner cavity of the desuperheater is filled with cooling water and the side walls are provided with a number of fins arranged evenly;

A coil is arranged between the small sleeve and the outer wall of the desuperheater, and the coil is filled with air at room temperature.

Further, an inclined included angle is set between the fin and the inner cavity side wall, and the included angle ranges from 15° to 90°.

Further, the included angle ranges from 30° to 60°.

Further, the value of the included angle is 30°, 45°, 50° or 60°.

Further, the coil includes a front coil and a rear coil whose diameters gradually decrease from large to small.

Further, the diameter ratio of the front coil tube and the rear coil tube is 3:1.

Further, the first water jacket is provided with three rectangular holes in cross-section, and the cross-sectional areas of the three rectangular holes are arranged in order from small to large.

Further, the flange of the large sleeve is provided with a second water jacket.

Further, the cross section of the second water jacket is rectangular or circular.

The present invention also provides a blast furnace smelting process provided with the oxygen-enriched coal injection tuyere as described above, the smelting process comprising the step of using the oxygen-enriched coal injection tuyere;

Step 1) open the furnace hood, send the appropriate proportion of iron ore and charge mixture into the furnace body, and then close the furnace hood;

Step 2) Turn on the circulating water cooling equipment, and the cooling water enters the inner cavity of the desuperheater and the first water jacket inside the middle jacket respectively, and realizes a water cooling cycle for the desuperheater in the middle jacket and the small jacket;

Step 3) Turn on the circulating air-cooling equipment, the air pump enters the cold air from the inlet of the desuperheater into the inner cavity, and after absorbing the heat, it flows out from the outlet of the desuperheater, and the coil between the small sleeve and the outer wall of the desuperheater is cooled by the cold air. The air-cooled cooling cycle is carried out to achieve the purpose of reducing the internal temperature of the small sleeve, forming a water-cooled cooling method for the middle sleeve first, then air-cooled cooling in the small sleeve, and then water-cooled cooling on the outside of the blowing pipe at the center position. The purpose is to form the cooling of water cooling, air cooling and water cooling three-layer circulating cooling;

Step 4) After the oxygen-enriched nozzle and the pulverized coal nozzle are opened at the same time, ignition is performed to burn the fed coal gas, oxygen-enriched oxygen and pulverized coal;

Step 5) make the temperature of the mixture of iron ore and charge in the furnace body reach 900-1100 ° C, and reduce the iron ore;

Step 6) After the reduction is completed, the tap hole is opened at the appropriate time, and the reduced molten iron is released.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention prolongs the service life of the tuyere and improves the labor efficiency of smelting;

2. The present invention also rationally uses the air-cooled structure to save water resources;

3. The present invention changes the conventional structure of the tuyere, reduces the frequency of replacing the tuyere, and reduces the labor intensity of workers.

Description of drawings

Fig. 1 is the overall structure diagram of the blast furnace that the present invention is provided with oxygen-enriched coal injection tuyere;

Fig. 2 is the structural sectional view of embodiment 1;

3 is a sectional view of the structure of the second embodiment.

reference number

In the figure, 1—slag outlet; 2—heart; 3—tuyere; 30—inner cavity; 31—fins; 32—blowing pipe; 33—front coil; 34—flange; 35—large set; 36— The first water jacket; 37—the middle sleeve; 38—the rear coil; 39—the small sleeve; 310—the protective body; Gas nozzle; 6—furnace body; 7—furnace cover.

Detailed ways

The specific implementation of a blast furnace with an oxygen-enriched coal injection tuyere of the present invention will be further described below with reference to the examples. The following examples are only used to illustrate the technical solutions of the present invention more clearly, and cannot be used to limit the protection scope of the present invention; Various changes and modifications can be made, so all equivalent technical solutions also belong to the scope of the present invention.

Example 1

As shown in Figures 1-2, a blast furnace with oxygen-enriched coal injection tuyere according to the present invention includes a furnace hood 7, a furnace body 6, a furnace bolly 4 and a hearth 2 arranged in sequence from top to bottom, and the furnace body 6 There is a gas nozzle 5 on it, a slag outlet 1 is arranged on the hearth 2, the blast furnace tuyere 3 between the boll 4 and the hearth 2, the blast furnace tuyere 3 is made of high-purity red copper material, and the blast furnace tuyere 3 is concrete. The structure includes a large sleeve 35 arranged on the furnace wall of the belly 4, the large sleeve 35 is sleeved with a middle sleeve 37, the middle sleeve 37 is sleeved with a small sleeve 39, and the center position of the small sleeve 39 is provided with a blow pipe 32, the middle sleeve 37 is provided with a first water jacket 36 inside; the outer side of the blow pipe 32 is fitted with a desuperheater 313, the desuperheater 313 is a structure similar to a small sleeve 39 and is provided with an inner cavity 30, and the front end of the cavity 30 is provided with a gradually shrinking shrinkage port 12 , the front end of the shrinkage port 312 is provided with a protective body 310 of a T structure, and the protective body 310 of the T structure plays the role of protecting the blowing pipe 32 from being eroded by molten iron and thermal fatigue, improving, the inner cavity 30 of the cooler 313 is filled with cooling water and There are several fins 31 evenly arranged on the side wall, and there is an inclined angle between the fin 31 and the side wall of the inner cavity 30, and the angle range is 0°～90°, and the preferred range is 15°～90° . Further, the value range of the included angle is preferably between 30° and 60°, and the value of the included angle is more preferably 30°, 45°, 50° or 60°. In this embodiment, the value of the included angle is 30°. Since the inner cavity 30 is provided with angled fins 31 , the cooling water circulating in the inner cavity 30 can better absorb the heat at the front end of the small sleeve 39 , thereby improving the service life of the small sleeve 39 .

In a preferred technical solution, a coil is arranged between the small sleeve 39 and the outer wall of the cooler 313, the coil is filled with air at room temperature, and the air pump circulates the air entering the small sleeve 39, thereby reducing the internal temperature of the small sleeve 39. In order to achieve the cooling effect of uniform heating and cooling, the coil includes a front coil 33 and a rear coil 38 whose diameters gradually decrease from large to small. The structures of the coils 33 correspond to each other, the thick structure of the front coil 33 corresponds to the thick structure of the small sleeve 39, and the thin structure of the rear coil 38 corresponds to the thin structure of the small sleeve 39, which plays the role of uniform heat absorption and heat release. . In this embodiment, the preferred technical solution is that the diameter ratio of the front coil tube 33 and the rear coil tube 38 is selected to be 3:1, so as to play the role of uniform temperature inside the small sleeve 39 .

In this embodiment, the preferred technical solution is that the first water jacket 36 is further provided with three structures with rectangular cross-sections, and the cross-sectional areas of the three rectangular holes are arranged in order from small to large, so as to reach the temperature inside the middle sleeve 38 . Uniform endothermic and exothermic effects.

The present invention also provides a blast furnace smelting process using an oxygen-enriched coal injection tuyere, and the smelting process includes the steps of using the oxygen-enriched coal injection tuyere:

Step 1) open the furnace bell 7, send the appropriate proportion of iron ore and charge mixture into the furnace shaft 6, then close the furnace bell 7;

Step 2) Turn on the circulating water cooling equipment, and the cooling water enters the inner cavity 30 of the desuperheater 313 and the first water jacket 36 inside the middle sleeve 37 respectively, and realizes a water cooling cycle for the desuperheater 313 in the middle sleeve 37 and the small sleeve;

Step 3) Open the circulating air-cooling equipment, the air pump enters the cold air into the inner cavity 30 from the inlet of the desuperheater 313, after absorbing the heat, it flows out from the outlet of the desuperheater 313, and the outer wall of the small sleeve 39 and the desuperheater 313 is affected by the cold air. The coils between the coils are air-cooled and cooled to achieve the purpose of reducing the internal temperature of the small sleeve 39, forming the first water-cooled cooling of the middle sleeve 37, and then the air-cooled cooling of the small sleeve 39. The purpose of water cooling is carried out on the outside of the blowing pipe 32, forming the cooling of water cooling, air cooling and water cooling three-layer circulating cooling. Due to the addition of the air cooling structure, the purpose of saving steel-making cooling water is achieved, and the effect of water saving is achieved;

Step 4) After the oxygen-enriched nozzle and the pulverized coal nozzle are opened at the same time, ignition is performed to burn the fed coal gas, oxygen-enriched oxygen and pulverized coal;

Step 5) make the temperature of the mixture of iron ore and charge in the furnace body 6 reach 900-1100 ° C, and reduce the iron ore;

Step 6) After the reduction is completed, the tap hole is opened at the appropriate time, and the reduced molten iron is released.

Example 2

As shown in FIG. 3 , this embodiment is further improved on the basis of Embodiment 1. The difference is that: a blast furnace provided with an oxygen-enriched coal injection tuyere provided by the present invention, in order to solve the problem that the flange is the easiest to accumulate heat , it is easy to cause the problem of excessive heat and hidden troubles. In the present invention, a second water jacket 314 is arranged in the flange of the large sleeve 35. The second water jacket 314 is communicated with the cooling water system and is used to rapidly cool down the flange that is most likely to accumulate heat, so as to protect the large sleeve 35 and improve the air outlet. The purpose of using efficiency and prolonging the service life of the tuyere. In a preferred technical solution, the cross section of the second water jacket 314 is a rectangular or circular structure.

The preferred specific embodiments and embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned embodiments and embodiments. Various changes are made under the premise of the inventive concept.

Claims (10)

1. A blast furnace with an oxygen-enriched coal injection tuyere comprises a furnace mantle (7), a furnace body (6), a furnace belly (4) and a furnace hearth (2) which are sequentially arranged from top to bottom, wherein a coal gas nozzle (5) is arranged on the furnace body (6), a slag outlet (1) is arranged on the furnace hearth (2), and a blast furnace tuyere (3) is arranged between the furnace belly (4) and the furnace hearth (2), and is characterized in that the blast furnace tuyere (3) comprises a large sleeve (35) arranged on the furnace wall of the furnace belly (4), a middle sleeve (37) is sleeved in the large sleeve (35), a small sleeve (39) is sleeved in the middle sleeve (37), a blowpipe (32) is arranged at the central position of the small sleeve (39), and a first water jacket (36) is arranged in the middle sleeve (37);

a temperature reducer (313) is sleeved outside the blow pipe (32), an inner cavity (30) of the temperature reducer (313) is filled with cooling water, and a plurality of uniformly arranged fins (31) are arranged on the side wall of the temperature reducer;

a coil pipe is arranged between the small sleeve (39) and the outer wall of the cooler (313), and the coil pipe is filled with air at normal temperature.

2. The blast furnace with an oxygen-enriched coal injection tuyere of claim 1, wherein an inclined included angle is formed between the fin (31) and the side wall of the inner cavity (30), and the included angle ranges from 15 ° to 90 °.

3. The blast furnace with an oxygen-enriched coal injection tuyere of claim 2, wherein the included angle ranges from 30 ° to 60 °.

4. The blast furnace with an oxygen-enriched coal injection tuyere of claim 3, wherein the included angle has a value of 30 °, 45 °, 50 ° or 60 °.

5. The blast furnace with an oxygen-enriched coal injection tuyere according to claim 1, wherein the coils comprise a front coil (33) and a rear coil (38) having diameters gradually reduced from large to small.

6. Blast furnace provided with an oxygen-enriched coal injection tuyere according to claim 5, characterized in that the diameter ratio of the front coil (33) and the rear coil (38) is 3: 1.

7. the blast furnace with an oxygen-enriched coal injection tuyere according to claim 1, wherein the first water jacket (36) is provided with three rectangular holes having cross sections, and the cross sectional areas of the three rectangular holes are arranged in the order of increasing from decreasing to increasing.

8. The blast furnace with an oxygen-enriched coal injection tuyere of claim 1, wherein a second water jacket (314) is provided in the flange of the large sleeve (35).

9. The blast furnace provided with an oxygen-enriched coal injection tuyere of claim 8, wherein the cross-section of the second water jacket (314) is rectangular or circular.

10. A smelting process for a blast furnace provided with an oxygen-rich coal injection tuyere of claim 1, characterized in that the smelting process comprises a step of using an oxygen-rich coal injection tuyere,

step 1) opening a furnace cover (7), feeding a mixture of iron ores and furnace charges with a proper proportion into a furnace body (6), and then closing the furnace cover (7);

step 2) circulating water cooling equipment is started, cooling water enters an inner cavity (30) of the cooler (313) and a first water jacket (36) in the middle sleeve (37) respectively, and the water cooling circulation is realized by the middle sleeve (37) and the cooler (313) in the small sleeve;

step 3) opening a circulating air cooling device, wherein cold air enters the inner cavity (30) from an inlet of the cooler (313) by the air pump, flows out from an outlet of the cooler (313) after heat is absorbed, and performs air cooling circulation on a coil pipe between the small sleeve (39) and the outer wall of the cooler (313) through the cold air so as to achieve the purpose of reducing the internal temperature of the small sleeve (39), form the purposes of performing water cooling on the small sleeve (37) firstly, performing air cooling on the small sleeve (39) and performing water cooling on the outer side of a blowing pipe (32) at the central position, and form cooling of three layers of circulating cooling of water cooling, air cooling and water cooling;

step 4) igniting the oxygen-enriched nozzle and the coal powder nozzle after the oxygen-enriched nozzle and the coal powder nozzle are opened simultaneously, so that the fed coal gas, oxygen-enriched oxygen and coal powder are combusted;

step 5) reducing the iron ore by enabling the temperature of the mixed material of the iron ore and the furnace burden in the furnace body (6) to reach 900-;

and 6) opening the tapping hole at certain time after the reduction is finished, and discharging the reduced molten iron.

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