CN109487031B - Dry dust removal and full waste heat recovery equipment for converter flue gas - Google Patents

Abstract

The invention discloses dry dust removal and full waste heat recovery equipment for converter flue gas, which comprises a vaporization cooling flue (1), a moving bed particle layer filter (2), a waste heat recovery device (3), a natural air cooling device (7), a wet electric dust collector (4), a fan (5) and a reversing valve (6), wherein a gas tank (8) and a chimney (9) are connected behind the reversing valve (6). The dry dust removal and full waste heat recovery device for converter flue gas can dry cool flue gas from a converter mouth above 1600 ℃ to about 70 ℃ and recover the waste heat of the flue gas above 150 ℃ in the cooling process.

Description

A converter flue gas dry dust removal and full waste heat recovery equipment

Technical Field

The invention relates to a converter flue gas dry dust removal and full waste heat recovery device.

Background technique

The production mode of smelting furnaces such as converters is intermittent, that is, the smelting furnace needs to be emptied, reloaded and other preparatory activities before and after smelting production.

During the preparation period, there is no intense smelting, the flue gas is mainly composed of air, the flue gas temperature is slightly increased after the air is heated by radiation, and there is no intense smoke.

During smelting production, with the increase of smelting intensity, the temperature of flue gas escaping from the furnace mouth can reach 1600℃, the CO content in the flue gas can be as high as 90%, and the dust carried by the flue gas can reach 150g/ ^Nm3 . The composition of the dust is complex, mainly FeO, _Fe2O3 , CaO, etc. The escaping flue gas and smoke dust will also undergo oxidation and heat release reactions in the subsequent _flue .

The smelting production time is generally no more than 20 minutes, and the preparation time is generally no more than 20 minutes. Due to this fast intermittent production method, the converter flue gas treatment facilities, especially those in the high-temperature section, need to have strong capabilities to cope with hot and cold shocks in large temperature ranges, high-concentration dust shocks, and explosive gas accumulation.

In order to meet the needs of subsequent flue gas dust removal, the converter flue gas needs to be cooled. As the circular economy has become more popular, the energy-saving and environmental protection awareness of domestic enterprises has gradually increased. The high-temperature waste heat of converter flue gas has been generally recovered. Research on the recovery of medium and low temperature waste heat of converter flue gas and the exploration of true dry dust removal technology have become the focus of many steel mills. The technical research and successful application of "dry dust removal and full waste heat recovery of converter flue gas" will bring about a complete change in the converter flue gas treatment process, which can completely eliminate the explosive factors of converter flue gas, and can completely realize the recovery of medium and low temperature waste heat of converter flue gas. It will also fundamentally change the existing converter flue gas wet (OG method) and dry (LT or DDS method) dust removal processes, and develop true dry dust removal and full waste heat recovery.

Summary of the invention

In order to achieve dry dust removal and full waste heat recovery, the present invention provides a converter flue gas dry dust removal and full waste heat recovery device, which can dry-cool the flue gas from the converter mouth above 1600°C to about 150°C, and recover all the flue gas waste heat in the cooling process.

The technical invention adopted by the present invention to solve its technical problem is: a converter flue gas dry dust removal and full waste heat recovery equipment, including a vaporization cooling flue, a moving bed particle layer filter, a waste heat recovery device, a natural air cooling device, a wet electrostatic precipitator, a fan and a reversing valve connected in sequence, and a gas tank and a chimney are also connected behind the reversing valve.

The moving bed particle layer filter comprises an inner cylinder, an intermediate cylinder and an outer cylinder which are sequentially arranged from the inside to the outside, a first annular cavity is formed between the inner cylinder and the intermediate cylinder, a filtering particle layer is arranged in the first annular cavity, the inner cylinder and the intermediate cylinder are both annular louver structures, the inner cylinder comprises a plurality of inner baffle strips arranged axially and inclined, and the intermediate cylinder comprises a plurality of outer baffle strips arranged axially and inclined.

The inner cylinder, the middle cylinder and the outer cylinder are all in an upright state. A supporting frame is also provided in the first annular cavity. A smoke inlet is provided at the lower part of the moving bed particle layer filter, a smoke outlet is provided at the upper part of the moving bed particle layer filter, the outlet of the vaporization cooling flue is connected to the smoke inlet, and the inlet of the waste heat recovery device is connected to the smoke outlet.

An inner cavity is provided in the inner cylinder, and the middle cylinder and the outer cylinder form a second annular cavity; the smoke inlet is connected to the inner cavity, and the smoke outlet is connected to the second annular cavity; or, the smoke inlet is connected to the second annular cavity, and the smoke outlet is connected to the inner cavity.

The support frame comprises a plurality of columns evenly arranged along the circumference of the intermediate cylinder, the first annular cavity is divided by the plurality of columns to form a plurality of fan-shaped chambers, and the filter particle layer is located in the fan-shaped chambers.

A rib plate is provided outside the column, and the inner baffle strips and the outer baffle strips are connected and fixed to the rib plate. A main cooling pipe is provided inside the column; an inner baffle cooling pipe is provided on the inner side of the inner baffle strip, and an outer baffle cooling pipe is provided on the outer side of the outer baffle strip. The inner baffle cooling pipe and the outer baffle cooling pipe are both connected to the main cooling pipe.

The inclination direction of the inner baffle strips is opposite to that of the outer baffle strips. The longitudinal sections of the left and right adjacent inner baffle strips and the outer baffle strips are mirror images of each other. From top to bottom, the distance between the left and right adjacent inner baffle strips and the outer baffle strips gradually decreases.

The converter flue gas dry dust removal and total waste heat recovery equipment also includes a clean particle bin, a charging valve, a dirty particle bin and a discharge valve; the lower part of the clean particle bin is connected to the upper part of the first annular cavity through a charging pipe, and the charging valve is arranged on the charging pipe; the upper part of the dirty particle bin is connected to the lower part of the first annular cavity through a discharge pipe, and the discharge valve is arranged on the discharge pipe.

The converter flue gas dry dust removal and total waste heat recovery equipment also includes a vibrating screen, a bucket elevator and an ash bin. The vibrating screen can separate the polluted particles in the polluted particle bin into purified particles and dust, the bucket elevator can transport the purified particles to the clean particle bin, and the ash bin can collect the dust.

The beneficial effects of the present invention are:

1. Recover the sensible heat of flue gas above 150℃ and realize full recovery of flue gas waste heat.

2. Realize pure dry cooling of converter flue gas from 150℃ to below 70℃, and the recovered converter gas does not contain moisture added due to gas cooling.

3. There is no explosion risk for medium and low temperature flue gas.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

FIG1 is a schematic diagram of the converter flue gas dry dust removal and total waste heat recovery equipment according to the present invention.

FIG. 2 is a schematic diagram of a moving bed particle filter.

FIG3 is a schematic longitudinal section diagram of the inner cylinder and the intermediate cylinder.

FIG. 4 is a schematic cross-sectional view of the inner cylinder and the middle cylinder.

FIG. 5 is a schematic diagram of a fan-shaped chamber.

FIG. 6 is a schematic diagram showing the connection between the inner baffle cooling pipe, the outer baffle cooling pipe and the main cooling pipe.

1. Vaporization cooling flue; 2. Moving bed particle layer filter; 3. Waste heat recovery device; 4. Wet electrostatic precipitator; 5. Fan; 6. Reversing valve; 7. Natural air cooling device; 8. Gas tank; 9. Chimney;

11. Clean particle bin; 12. Dirty particle bin; 13. Vibrating screen; 14. Bucket elevator; 15. Ash bin;

21. Inner cylinder; 22. Intermediate cylinder; 23. Outer cylinder; 24. Inner baffle strips; 25. Outer baffle strips; 26. Support frame; 27. Smoke inlet; 28. Smoke outlet; 29. Column; 210. Filter particle layer;

241. Inner baffle cooling pipe; 251. Outer baffle cooling pipe; 291. Main cooling pipe.

Detailed ways

It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

A converter flue gas dry dust removal and full waste heat recovery device comprises a vaporization cooling flue 1, a moving bed particle layer filter 2, a waste heat recovery device 3, a natural air cooling device 7, a wet electrostatic precipitator 4, a fan 5 and a reversing valve 6 which are connected in sequence, and a gas tank 8 and a chimney 9 are also connected behind the reversing valve 6, as shown in FIG1 .

The flue gas passes through the vaporization cooling flue 1 located above the converter. The flue gas with a temperature higher than 610°C enters the moving bed particle layer filter 2 to remove large particles and ash agglomerates, and then enters the waste heat recovery device 3 (convection heat exchange waste heat recovery device) to cool down to about 150°C. Most of the high-temperature radiation heat is recovered. After that, the flue gas enters the surface natural air cooling device 7, and the flue gas temperature is dry-cooled from 150°C to below 70°C. The flue gas below 70°C is dedusted by the wet electrostatic precipitator 4, and then discharged or recovered to the gas tank 8. The converter flue gas moving bed particle layer filter separates the large particles, ash agglomerates and other high-temperature solids carried by the converter flue gas and discharges them out of the device.

In this embodiment, the moving bed particle layer filter 2 includes an inner cylinder 21, an intermediate cylinder 22 and an outer cylinder 23 which are sequentially arranged from the inside to the outside. A first annular cavity is formed between the inner cylinder 21 and the intermediate cylinder 22. A filtering particle layer 210 is arranged in the first annular cavity. Both the inner cylinder 21 and the intermediate cylinder 22 are annular louver structures. The inner cylinder 21 includes a plurality of inner baffle strips 24 arranged axially and inclined, and the intermediate cylinder 22 includes a plurality of outer baffle strips 25 arranged axially and inclined, as shown in Figures 2 to 4.

In this embodiment, the inner cylinder 21, the middle cylinder 22 and the outer cylinder 23 are all in an upright state, the center line of the inner cylinder 21, the center line of the middle cylinder 22 and the center line of the outer cylinder 23 coincide, and a support frame 26 is also provided in the first annular cavity. A flue gas inlet 27 is provided at the lower part of the moving bed particle layer filter 2, and a flue gas outlet 28 is provided at the upper part of the moving bed particle layer filter 2. The outlet of the vaporization cooling flue 1 is connected to the flue gas inlet 27, and the inlet of the waste heat recovery device 3 is connected to the flue gas outlet 28.

In this embodiment, the particle layer 210 is filtered from top to bottom, and smoke can go in and out, or go in and out. To ensure that smoke does not stay, smoke can go in and out from the bottom or from the top, but not from the bottom or from the top, as shown in FIGS. 2 to 4 .

In this embodiment, an inner cavity is provided in the inner cylinder 21, and the middle cylinder 22 and the outer cylinder 23 form a second annular cavity; the smoke inlet 27 is connected to the inner cavity, and the smoke outlet 28 is connected to the second annular cavity; or, the smoke inlet 27 is connected to the second annular cavity, and the smoke outlet 28 is connected to the inner cavity.

Preferably, the smoke inlet 27 is connected to the inner cavity, and the smoke outlet 28 is connected to the second annular cavity. When in use, the polluted smoke first enters the inner cavity of the inner cylinder 21 from the smoke inlet 27, then passes through the filtration particle layer 210, and then enters the second annular cavity between the middle cylinder 22 and the outer cylinder 23, and the purified smoke after filtration is discharged from the smoke outlet 28.

In this embodiment, the support frame 26 contains a plurality of columns 29 evenly arranged along the circumference of the middle cylinder 22. The weight of the inner cylinder 21, the middle cylinder 22 and the outer cylinder 23 can be borne by the support frame 26. The first annular cavity is divided by the plurality of columns 29 to form a plurality of (e.g., 3 to 15) fan-shaped chambers, and the filter particle layer 210 is located in the fan-shaped chambers, as shown in Figures 4 and 5.

In this embodiment, a rib plate is provided outside the column 29, and the inner baffle strips 24 and the outer baffle strips 25 are both connected and fixed to the rib plate. A main cooling pipe 291 is provided inside the column 29; an inner baffle cooling pipe 241 is provided on the inner side of the inner baffle strips 24, and an outer baffle cooling pipe 251 is provided on the outer side of the outer baffle strips 25. The inner baffle cooling pipe 241 and the outer baffle cooling pipe 251 are both connected to the main cooling pipe 291, as shown in Figure 6.

In this embodiment, the inclination direction of the inner baffle strip 24 is opposite to that of the outer baffle strip 25, and the longitudinal sections of the inner baffle strips 24 and the outer baffle strips 25 adjacent to each other are mirror images of each other, and the distance between the inner baffle strips 24 and the outer baffle strips 25 adjacent to each other gradually decreases from top to bottom, as shown in Figure 3. The distance between the two inner baffle strips 24 adjacent to each other is greater than the diameter of the filter particles in the filter particle layer 210, and the distance between the two outer baffle strips 25 adjacent to each other is greater than the diameter of the filter particles in the filter particle layer 210.

In this embodiment, the converter flue gas dry dust removal and full waste heat recovery equipment further includes a clean particle bin 11, a charging valve, a dirty particle bin 12 and a discharge valve; the lower part of the clean particle bin 11 is connected to the upper part of the first annular cavity through a charging pipe, and the charging valve is arranged on the charging pipe; the upper part of the dirty particle bin 12 is connected to the lower part of the first annular cavity through a discharge pipe, and the discharge valve is arranged on the discharge pipe. The filter particle layer 210 can be a quartz sand layer, an alumina particle layer or a steel ball layer.

In this embodiment, the converter flue gas dry dust removal and total waste heat recovery equipment also includes a vibrating screen 13, a bucket elevator 14 and an ash bin 15. The vibrating screen 13 can separate the polluted particles in the polluted particle bin 12 into purified particles and dust. The bucket elevator 14 can transport the purified particles to the clean particle bin 11. The ash bin 15 can collect the dust, as shown in Figure 1.

The working process of the converter flue gas dry dust removal and full waste heat recovery equipment is introduced below.

The converter generates high-temperature flue gas during the smelting process. The high-temperature flue gas radiates heat in large quantities through the vaporization cooling flue 1 located above the converter. The flue gas with a temperature higher than 610°C then passes through the converter flue gas moving bed particle layer filter 2, the waste heat recovery device 3 (cooling to 150°C), the surface natural air cooling device 7 (cooling to below 70°C), the wet electrostatic precipitator 4 (flue gas purification), the fan 5, and the reversing valve 6 in the flue gas switching station. Then, one path of qualified converter gas enters the gas tank 8; the other path of unrecovered flue gas is discharged into the atmosphere through the chimney 9 after being burned out, as shown in Figure 2.

The flue gas with a temperature higher than 610°C carries a large amount of particles, ash and other dust into the converter flue gas moving bed particle layer filter 2. Large particles, ash and other high-temperature solids are blocked by the particle layer, and the relatively clean flue gas leads to the surface natural air cooling device 7.

During the converter preparation activities, large particles, ash agglomerates and other high-temperature solids blocked by the particle layer are discharged into the dirty particle bin 12 located below the converter flue gas moving bed particle layer filter 2 together with the particle layer. The dirty particles in the dirty particle bin 12 are separated by a solid separation device such as a vibrating screen 13, and the qualified particle layer is transported to a clean particle bin at a high place by a bucket elevator 14 and other machinery for standby use. The dirty particles in the dirty particle bin are separated by a solid separation device such as a vibrating screen, and the dust is discharged into the ash bin 15 below for reuse. The dust collected by the converter flue gas dry dust removal and full waste heat recovery system can be used as converter cold material, partially replacing the scrap steel or iron ore required for converter smelting.

The surface type natural air cooling device 7 also plays the role of flue gas transportation. No steam or water is injected into the whole system, and there is no water treatment facility.

In the present invention, the converter flue gas is passed through at least one set of heat exchange device and at least one set of converter flue gas moving bed particle layer filter to recover flue gas sensible heat. The low-temperature flue gas is further passed through a surface natural air cooling device and a wet electrostatic precipitator to achieve the purpose of cooling and dust removal.

The converter flue gas passes through the heat exchange device mainly based on radiation heat exchange, the converter flue gas moving bed particle layer filter, the heat exchange device mainly based on convection heat exchange, the surface natural air cooling device, and the wet electrostatic precipitator for cooling and dust removal. After passing through the fan and the switching valve, the gas enters the gas cabinet, and the unrecycled flue gas passes through the switching valve and is burned out and discharged directly to the atmosphere through the chimney.

In the present invention, a radiation heat exchange device and a convection heat exchange device are used to recover the high-quality thermal enthalpy of the converter flue gas, a surface natural air cooling device is used for deep cooling, a converter flue gas moving bed particle layer filter and a wet electrostatic precipitator are used for flue gas dust removal, a fan is used for power transmission, and a switching device is used to separate the usable coal gas and the flue gas discharged into the atmosphere.

In the converter flue gas full dry cooling method, the converter flue gas passes through at least one set of heat exchange device and one set of converter flue gas moving bed particle layer filter to recover the flue gas sensible heat. The low-temperature flue gas is further cooled by the surface natural air cooling device. The low-temperature flue gas is further dusted by the wet electrostatic precipitator.

The converter flue gas passes through the heat exchange device mainly based on radiation heat exchange, the converter flue gas moving bed particle layer filter, the heat exchange device mainly based on convection heat exchange, the surface natural air cooling device, and the wet electrostatic precipitator for cooling and dust removal. After passing through the fan and the switching valve, the gas enters the gas cabinet, and the unrecycled flue gas passes through the switching valve and is burned out and discharged directly to the atmosphere through the chimney.

The converter flue gas radiation heat exchange device adopts the form of membrane wall. The cooling medium of the membrane wall is generally water, but it can also be heat transfer oil, molten salt, etc. The cooling method is generally evaporative cooling, and it can also be non-phase change cooling. The flow form of flue gas in the radiation heat exchange device is similar to plunger flow. There are no vortex areas such as flue gas retention in the radiation heat exchange device.

In the flue gas process, the converter flue gas moving bed particle layer filter is after the radiation heat exchange device and before the convection heat exchange device (so the flue gas temperature during smelting can be higher than 610℃). During converter smelting, the converter flue gas moving bed particle layer filter structure operates in the form of a fixed bed, the particle layer does not move, and the dust is captured in the particle layer. After the converter stops smelting and enters production preparation, the converter flue gas moving bed particle layer filter structure is converted into a moving bed form. The particle layer carries the captured large particles, ash and other high-temperature solids and moves downward into the dirty particle bin below the converter flue gas moving bed particle layer filter structure, and then separates the particle layer from the dust. The particles separated from the dust are sent to the clean particle bin above the converter flue gas moving bed particle layer filter structure for standby use. The flow form of flue gas in the converter flue gas moving bed particle layer filter structure is similar to that of a plunger flow. There are no vortices and other areas where flue gas is retained in the converter flue gas moving bed particle layer filter structure.

Convective heat exchange devices generally adopt the form of horizontal flushing and horizontal light tubes, and finned tubes can also be used. The tube bundle is generally arranged in a cross-flow arrangement, or it can be arranged in a co-flow arrangement. The cooling medium is generally water, but it can also be heat transfer oil, molten salt, etc. The cooling method is generally evaporative cooling, or it can be non-phase change cooling. The flow form of flue gas in the convection heat exchange device is similar to that of a plunger flow. There are no vortexes and other areas where flue gas is retained in the convection heat exchange device.

After the convection heat exchange device, a surface natural air cooling device is used to deeply cool the flue gas, realizing pure dry cooling of the converter flue gas from 150°C to below 70°C. The main body of the air cooling device adopts a flue gas conveying pipeline, and fins for enhancing heat exchange can be set on the inner and outer surfaces of the pipeline. The flow form of the flue gas in the air cooling device is similar to that of a plunger flow. There are no vortexes and other areas where the flue gas is retained in the air cooling device. The air cooling device is set in front of the wet electrostatic precipitator. After the flue gas temperature is reduced to between 100°C and 70°C, a wet electrostatic precipitator is used to remove dust from the flue gas.

The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the protection scope of the patent of the present invention, should still fall within the scope of this patent. In addition, the technical features of the present invention can be freely combined with each other, with each other and with each other, and with each other.

Claims (3)

1. The dry type dust removal and full waste heat recovery device for the converter flue gas is characterized by comprising a vaporization cooling flue (1), a moving bed particle layer filter (2), a waste heat recovery device (3), a natural air cooling device (7), a wet type electric dust collector (4), a fan (5) and a reversing valve (6) which are sequentially connected, wherein a gas tank (8) and a chimney (9) are further connected behind the reversing valve (6);

the moving bed particle layer filter (2) comprises an inner layer cylinder body (21), a middle cylinder body (22) and an outer layer cylinder body (23) which are sequentially sleeved from inside to outside, a first annular cavity is formed between the inner layer cylinder body (21) and the middle cylinder body (22), a filter particle layer (210) is arranged in the first annular cavity, the inner layer cylinder body (21) and the middle cylinder body (22) are of annular louver structures, the inner layer cylinder body (21) comprises a plurality of inner baffle plate strips (24) which are arranged in an inclined manner along the axial direction, and the middle cylinder body (22) comprises a plurality of outer baffle plate strips (25) which are arranged in an inclined manner along the axial direction;

the inner layer cylinder body (21), the middle cylinder body (22) and the outer layer cylinder body (23) are all in an upright state, a supporting frame (26) is further arranged in the first annular cavity, a flue gas inlet (27) is formed in the lower portion of the moving bed particle layer filter (2), a flue gas outlet (28) is formed in the upper portion of the moving bed particle layer filter (2), an outlet of the vaporization cooling flue (1) is connected with the flue gas inlet (27), and an inlet of the waste heat recovery device (3) is connected with the flue gas outlet (28);

an inner cavity is arranged in the inner layer cylinder (21), and the middle cylinder (22) and the outer layer cylinder (23) form a second annular cavity; a flue gas inlet (27) is communicated with the inner cavity, and a flue gas outlet (28) is communicated with the second annular cavity; or, a flue gas inlet (27) is communicated with the second annular cavity, and a flue gas outlet (28) is communicated with the inner cavity;

the support frame (26) comprises a plurality of upright posts (29) which are uniformly arranged along the circumferential direction of the middle cylinder (22), the first annular cavity is divided by the plurality of upright posts (29) to form a plurality of fan-shaped chambers, and the filter particle layer (210) is positioned in the fan-shaped chambers;

a rib plate is arranged outside the upright post (29), the inner baffle strip (24) and the outer baffle strip (25) are connected and fixed with the rib plate, and a main cooling pipe (291) is arranged in the upright post (29); an inner baffle cooling pipe (241) is arranged at the inner side of the inner baffle strip (24), an outer baffle cooling pipe (251) is arranged at the outer side of the outer baffle strip (25), and the inner baffle cooling pipe (241) and the outer baffle cooling pipe (251) are communicated with the main cooling pipe (291);

the inclination direction of the inner baffle strip (24) is opposite to that of the outer baffle strip (25), the longitudinal sections of the left and right adjacent inner baffle strips (24) and the longitudinal sections of the outer baffle strips (25) are mirror images, and the distance between the left and right adjacent inner baffle strips (24) and the outer baffle strips (25) is gradually reduced along the direction from top to bottom;

the distance between the two upper and lower adjacent inner baffle strips (24) is larger than the diameter of the filter particles in the filter particle layer (210), and the distance between the two upper and lower adjacent outer baffle strips (25) is also larger than the diameter of the filter particles in the filter particle layer (210); the filter particle layer (210) is a quartz sand layer, an alumina particle layer or a steel ball layer.

2. The converter fume dry dust removal and total waste heat recovery device according to claim 1, characterized in that it further comprises a clean particle bin (11), a charging valve, a dirty particle bin (12) and a discharge valve; the lower part of the clean particle bin (11) is communicated with the upper part of the first annular cavity through a charging pipeline, and the charging valve is arranged on the charging pipeline; the upper part of the dirt particle bin (12) is communicated with the lower part of the first annular cavity through a discharge pipeline, and the discharge valve is arranged on the discharge pipeline.

3. The converter fume dry dust removal and total waste heat recovery device according to claim 2, further comprising a vibrating screen (13), a bucket elevator (14) and an ash bin (15), wherein the vibrating screen (13) can separate the pollutant particles in the pollutant particle bin (12) into net particles and dust, the bucket elevator (14) can convey the net particles into the net particle bin (11), and the ash bin (15) can collect the dust.