Blast furnace gas treatment system and process

Abstract

The invention discloses a blast furnace gas treatment system and process, and solves the technical problem that the energy consumption of an industrial furnace is increased due to the fact that moisture in blast furnace gas subjected to a wet dechlorination process increases the burden of a blast furnace gas combustion user in the prior art. The blast furnace gas treatment system comprises a dechlorination tower, a dehydration section and a reheating section which are communicated in sequence, a wet dechlorination system is arranged in the dechlorination tower, and the gas inlet end of the dechlorination tower is communicated with the gas outlet end of the blast furnace gas supply system; a dehydration system for removing moisture in the gas is arranged in the dehydration section; a heating system used for heating gas is arranged in the reheating section, and the gas outlet end of the reheating section communicates with the interior of the industrial furnace. According to the blast furnace gas treatment system, water-containing blast furnace gas can be changed into hot dry blast furnace gas through the dehydration section and the reheating section, and when the hot dry blast furnace gas is burnt in an industrial furnace, due to the fact that the moisture content is reduced, energy consumption and the content of CO2 in exhausted flue gas can be reduced, and the purposes of saving energy and reducing carbon are achieved.

Description

Technical Field

[0001] The present application belongs to the technical field of energy conservation and carbon reduction, and specifically relates to a blast furnace gas treatment system and process. Background Art

[0002] Blast furnace gas is a combustible gas produced as a by-product in the blast furnace ironmaking process and is an important secondary energy source for the entire steel process.

[0003] Due to the changes in blast furnace raw materials and the application of dry dust removal technology in blast furnace gas, the chloride ion concentration in blast furnace gas has increased significantly. The presence of chloride ions makes blast furnace gas corrosive. During the transportation process, the transmission and distribution pipelines are prone to corrosion and perforation, which may lead to safety hazards such as blast furnace gas leakage.

[0004] In order to avoid the above problems, at present, the end of the blast furnace gas supply system adopts a dechlorination process (including dry dechlorination and wet dechlorination) to remove chloride ions in the blast furnace gas; most steel companies use a wet dechlorination process with good dechlorination effect, simple operation and low cost, but this process will change the blast furnace gas from dry gas to a wet mixed gas saturated with water content. The moisture in the wet mixed gas increases the burden of blast furnace gas combustion users, resulting in increased energy consumption of industrial furnaces and kilns, and CO2 emissions also increase accordingly. Therefore, inventing a combined process for blast furnace gas purification and energy saving to reduce the energy consumption of industrial furnaces is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] In order to solve the above technical problems, the present application provides a blast furnace gas treatment system on the one hand to solve the technical problem in the prior art that the moisture in the blast furnace gas after the wet dechlorination process will increase the burden on blast furnace gas combustion users and lead to increased energy consumption of industrial furnaces.

[0006] The technical solution adopted to achieve the purpose of this application is:

[0007] A blast furnace gas treatment system comprises a dechlorination tower, a dehydration section and a reheating section which are connected in sequence;

[0008] A wet dechlorination system is arranged in the dechlorination tower, and the air inlet end of the dechlorination tower is connected to the air outlet end of the blast furnace gas supply system;

[0009] The dehydration section is provided with a dehydration system for removing moisture from the gas;

[0010] The reheating section is provided with a heating system for heating the gas, and the gas outlet end of the reheating section is connected to the industrial furnace.

[0011] In order to better realize the present application, further optimization is made in the above structure, wherein the dehydration section includes a dehydration tank and a primary dehydrator, a secondary dehydrator and a final dehydrator for removing moisture from the gas;

[0012] The primary dehydrator and the final dehydrator are respectively arranged at the air inlet end and the air outlet end of the dehydration tank, the air outlet end of the dechlorination tower is connected to the air inlet end of the primary dehydrator, and the air outlet end of the final dehydrator is connected to the air inlet end of the reheating section;

[0013] The intermediate dehydrator is arranged in the middle of the dehydration tank.

[0014] In order to better realize the present application, further optimization is made in the above structure, wherein the primary dehydrator includes a cyclone dehydrator;

[0015] The air outlet end of the dechlorination tower is connected to the air inlet end of the cyclone dehydrator, the air outlet end of the cyclone dehydrator is connected to the air inlet end of the dehydration tank, the height of the air inlet end of the cyclone dehydrator is greater than the height of the air outlet end of the cyclone dehydrator, and a first drain port is provided at the bottom of the cyclone dehydrator.

[0016] In order to better realize the present application, further optimization is made in the above structure, wherein the intermediate dehydrator includes a first heat exchange system and a second heat exchange system for reducing the gas temperature;

[0017] The heat exchange end of the first heat exchange system and the heat exchange end of the second heat exchange system both extend into the interior of the dehydration tank, and the heat exchange end of the first heat exchange system is located between the air inlet end of the dehydration tank and the heat exchange end of the second heat exchange system.

[0018] In order to better implement the present application, further optimization is made in the above structure, and a second drain outlet is provided at the bottom of the dehydration tank.

[0019] In order to better realize the present application, further optimization is made in the above structure, the final stage dehydrator includes a wire mesh demister, the shape of the wire mesh demister matches the shape of the cross section of the dehydration tank, and the wire mesh demister is sealed at the air outlet end of the dehydration tank.

[0020] In order to better realize the present application, further optimization is made in the above structure, wherein the reheating section includes a reheating tank and a third heat exchange system for heating the gas;

[0021] The air inlet end of the reheating tank is connected to the air outlet end of the dehydration section, and the air outlet end of the reheating tank is connected to the industrial furnace;

[0022] The heat exchange end of the third heat exchange system extends to the interior of the reheating tank.

[0023] In order to better realize the present application, further optimization is made in the above structure, and the third heat exchange system is connected to the waste heat recovery port of the ironmaking area.

[0024] In order to better realize the present application, further optimization is made in the above structure. The air inlet of the dechlorination tower is arranged near the bottom of the dechlorination tower, the air outlet of the dechlorination tower is arranged at the top of the dechlorination tower, and the wet dechlorination system is located between the air inlet of the dechlorination tower and the air outlet of the dechlorination tower.

[0025] On the other hand, the present application also provides a blast furnace gas treatment process, the treatment process is implemented by the above-mentioned blast furnace gas treatment system, and the treatment process comprises the following steps:

[0026] The chlorine-containing blast furnace gas after dry dust removal is sent into the dechlorination tower, and is dechlorinated by the wet dechlorination system to form water-saturated water-containing blast furnace gas;

[0027] The water-containing blast furnace gas enters the dehydration section and is dehydrated by the dehydration system to form cold-dried blast furnace gas;

[0028] The cold dry blast furnace gas enters the reheating section and is heated by the heating system to form hot dry blast furnace gas.

[0029] It can be seen from the above technical scheme that the dehydration section in the blast furnace gas treatment system provided by the present application can remove moisture from the water-containing blast furnace gas, so that the water-containing blast furnace gas forms cold-dried blast furnace gas, and then the cold-dried blast furnace gas is heated through the reheating section to form hot-dried blast furnace gas. When the hot-dried blast furnace gas is burned in an industrial furnace, due to the reduction in the degree of moisture contained in the hot-dried blast furnace gas, a low-energy combustion process is realized, and at the same time, the content of CO2 in the exhaust gas is reduced, so as to achieve the purpose of energy saving and carbon reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the structure of a blast furnace gas treatment system provided in this application;

[0031] Figure 2 A schematic diagram of the structure of a dechlorination tower in a blast furnace gas treatment system provided in this application;

[0032] Figure 3 A schematic diagram of the structure of a dehydration section in a blast furnace gas treatment system provided in this application;

[0033] Figure 4 A schematic diagram of the structure of a reheating section in a blast furnace gas treatment system provided in this application.

[0034] Description of reference numerals:

[0035] 1-dechlorination tower, 11-wet dechlorination system;

[0036] 2-dehydration section, 21-dehydration tank, 211-second drain outlet, 22-primary dehydrator, 221-first drain outlet, 23-intermediate dehydrator, 231-first heat exchange system, 232-second heat exchange system, 24-final dehydrator;

[0037] 3-reheating section, 31-reheating tank, 32-third heat exchange system. DETAILED DESCRIPTION

[0038] In order to enable technicians in the technical field to which the present application belongs to understand the present application more clearly, the technical solution of the present application is described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0039] In the embodiments of the present application, Figures 1 to 4 As shown, a blast furnace gas treatment system comprises a dechlorination tower 1, a dehydration section 2 and a reheating section 3 which are connected in sequence. Figure 1 ;in,

[0040] A dehydration system for removing moisture from the gas is provided in the dehydration section 2;

[0041] A heating system for heating gas is provided in the reheating section 3, and the gas outlet end of the reheating section 3 is connected to the industrial furnace;

[0042] A wet dechlorination system 11 is arranged in the dechlorination tower 1, and the air inlet end of the dechlorination tower 1 is connected to the air outlet end of the blast furnace gas supply system; in this embodiment, the air inlet of the dechlorination tower 1 is arranged near the bottom of the dechlorination tower 1, and the air outlet of the dechlorination tower 1 is arranged at the top of the dechlorination tower 1, and the wet dechlorination system 11 is located between the air inlet of the dechlorination tower 1 and the air outlet of the dechlorination tower 1, and the chlorine-containing blast furnace gas entering the dechlorination tower 1 will flow from bottom to top toward the air outlet of the dechlorination tower 1, and the chlorine in the chlorine-containing blast furnace gas will be absorbed by the water and / or alkaline solution sprayed by the wet dechlorination system 11. This arrangement can increase the contact time between the chlorine-containing blast furnace gas and the water and / or alkaline solution to improve the dechlorination effect, and the water content in the dechlorinated blast furnace gas is saturated to become water-containing blast furnace gas;

[0043] When the water-containing blast furnace gas is discharged from the dechlorination tower 1, it enters the dehydration section 2. The dehydration system in the dehydration section 2 can remove the water in the water-containing blast furnace gas, and then send it to the reheating section 3 for heating to form hot dry blast furnace gas;

[0044] The hot dry blast furnace gas enters the industrial furnace through the gas outlet end of the reheating section 3. When the industrial furnace burns the hot dry blast furnace gas, a low-energy combustion process is achieved due to the reduction in the moisture content of the hot dry blast furnace gas. At the same time, the CO2 content in the exhaust gas is reduced, so as to achieve the purpose of energy saving and carbon reduction.

[0045] In some embodiments, the dehydration section 2 includes a dehydration tank 21 and the dehydration system, the dehydration system includes a primary dehydrator 22, a secondary dehydrator 23 and a final dehydrator 24, see Figure 2 ;in,

[0046] The primary dehydrator 22 and the final dehydrator 24 are respectively arranged at the air inlet and air outlet of the dehydration tank 21, the air outlet of the dechlorination tower 1 is connected to the air inlet of the primary dehydrator 22, and the air outlet of the final dehydrator 24 is connected to the air inlet of the reheating section 3;

[0047] The intermediate dehydrator 23 is arranged in the middle of the dehydration tank 21;

[0048] The above-mentioned dehydration system (primary dehydrator 22, intermediate dehydrator 23 and final dehydrator 24) can effectively improve the dehydration efficiency of the dehydration section 2, so as to better intercept and absorb the moisture in the water-containing blast furnace gas, so as to reduce the burden on the blast furnace gas combustion users;

[0049] At the same time, reducing the moisture in the water-containing blast furnace gas can prevent the moisture from adhering to the subsequent transmission and distribution pipelines, causing rust in the transmission and distribution pipelines, thereby increasing the service life of the pipelines and equipment.

[0050] In some embodiments, the primary dehydrator 22 comprises a cyclone dehydrator; wherein,

[0051] The cyclone dehydrator is a mechanical dehydration device, the gas outlet end of the dechlorination tower 1 is connected to the gas inlet end of the cyclone dehydrator, and the gas outlet end of the cyclone dehydrator is connected to the gas inlet end of the dehydration tank 21;

[0052] The height of the air inlet end of the cyclone dehydrator is greater than the height of the air outlet end of the cyclone dehydrator, and a first drain port 221 is provided at the bottom of the cyclone dehydrator;

[0053] The water content of the water-containing blast furnace gas discharged from the dechlorination tower 1 is saturated. The cyclone dehydrator can remove the droplets in the water-containing blast furnace gas, thereby reducing the water content in the water-containing blast furnace gas. The remaining water content of the water-containing blast furnace gas (the water content that is difficult to be removed by the cyclone dehydrator) will enter the dehydration tank 21 together with the blast furnace gas, and will be removed in turn through the intermediate dehydrator 23 and the final dehydrator 24;

[0054] The water removed by the cyclone dehydrator gathers at the bottom of the primary dehydrator 22 and is discharged outward from the first drain port 221 .

[0055] After the large droplets of liquid in the water-containing blast furnace gas are removed by the cyclone dehydrator, the remaining water is difficult to be removed by mechanical dehydration. In this embodiment, the intermediate dehydrator 23 uses condensation to condense and drip the water in the water-containing blast furnace gas to achieve the dehydration effect; specifically, the intermediate dehydrator 23 includes a first heat exchange system 231 and a second heat exchange system 232 for reducing the gas temperature;

[0056] The heat exchange end of the first heat exchange system 231 and the heat exchange end of the second heat exchange system 232 both extend to the interior of the dehydration tank 21, and the heat exchange end of the first heat exchange system 231 is located between the air inlet end of the dehydration tank 21 and the heat exchange end of the second heat exchange system 232;

[0057] The temperature of the internal medium of the heat exchange end of the first heat exchange system 231 and the heat exchange end of the second heat exchange system 232 is much lower than the temperature of the water-containing blast furnace gas, so that the internal medium of the heat exchange end of the first heat exchange system 231 and the heat exchange end of the second heat exchange system 232 can absorb the heat in the water-containing blast furnace gas to reduce the temperature of the water-containing blast furnace gas. The moisture in the water-containing blast furnace gas will condense and precipitate, and drip to the bottom of the dehydration tank 21 under the action of gravity. The moisture in the water-containing blast furnace gas passing through the intermediate dehydrator 23 will be further reduced.

[0058] In order to avoid water accumulation in the dehydration tank 21, a second drain port 211 is provided at the bottom of the dehydration tank 21 so that the liquid in the dehydration tank 21 can be discharged outward through the second drain port 211, so that the blast furnace gas treatment system can maintain a stable working state for a long time.

[0059] It should be noted that the media in the first heat exchange system 231 and the second heat exchange system 232 in this embodiment are lithium bromide and chilled water respectively.

[0060] In some embodiments, the above-mentioned final dehydrator 24 includes a wire mesh demister, the shape of which matches the shape of the cross section of the dehydration tank 21 in the dehydration section 2, and the wire mesh demister is sealed at the gas outlet end of the dehydration tank 21;

[0061] The mist water in the water-containing blast furnace gas that has not been completely condensed into droplets is removed at the gas outlet end of the dehydration tank 21 using the wire mesh defogger principle, so that the moisture in the water-containing blast furnace gas is completely removed to form cold-dried blast furnace gas. Since there is very little moisture in the cold-dried blast furnace gas, and the water content in the hot-dried blast furnace gas after reheating is lower than the saturated water content of the blast furnace gas, no condensed water will be precipitated in the subsequent transmission and distribution process, so that the subsequent transmission and distribution pipelines will not rust, etc., to ensure the service life of the blast furnace gas treatment system.

[0062] It should be noted that the above-mentioned wire mesh demister sealed at the gas outlet end of the dehydration tank 21 means that the wire mesh demister completely covers the gas outlet end of the dehydration tank 21, and all the water-containing blast furnace gas in the dehydration tank 21 must pass through the wire mesh demister before entering the reheating section 3 for heating treatment to ensure the dehydration effect of the dehydration section 2.

[0063] In some embodiments, the above-mentioned reheating section 3 includes a reheating tank 31 and a third heat exchange system 32 for heating gas; wherein,

[0064] The air inlet end of the reheating tank 31 is connected to the air outlet end of the dehydration tank 21. In this embodiment, the air inlet end of the reheating tank 31 and the air outlet end of the dehydration tank 21 are connected and fixed by welding to prevent the cold dry blast furnace gas from leaking from the air inlet end of the reheating tank 31 and the air outlet end of the dehydration tank 21, thereby causing environmental pollution.

[0065] The gas outlet end of the reheating tank 31 is connected to the industrial furnace;

[0066] The heat exchange end of the third heat exchange system 32 extends to the interior of the reheating tank 31;

[0067] The temperature of the internal medium of the heat exchange end of the third heat exchange system 32 is higher than the temperature of the cold dry blast furnace gas, so that the internal medium of the heat exchange end of the third heat exchange system 32 can exchange heat with the cold dry blast furnace gas, and heat the cold dry blast furnace gas to form hot dry blast furnace gas. In this embodiment, the third heat exchange system 32 is connected to the waste heat recovery port of the ironmaking area, and the hot air of the ironmaking area is sent to the third heat exchange system 32, and the waste heat of the ironmaking area is used to heat the cold dry blast furnace gas to achieve heat recovery and utilization.

[0068] Since the temperature of the low-quality hot air in the iron-making area is difficult to recover energy through power generation and other means, it is wasted in the prior art. The present embodiment recovers the hot air in the iron-making area and uses it to heat the cold-dried blast furnace gas, thereby realizing the recovery and utilization of heat energy. At the same time, the cold-dried blast furnace gas is heated and then sent to the industrial furnace for combustion, thereby reducing the energy consumption when the industrial furnace burns the blast furnace gas, thereby achieving energy-saving effects.

[0069] Based on the above blast furnace gas treatment system, this embodiment provides a blast furnace gas treatment process, which includes the following steps:

[0070] The chlorine-containing blast furnace gas after dry dust removal enters the dechlorination tower 1, and is dechlorinated by the wet dechlorination system 11 to form water-saturated water-containing blast furnace gas;

[0071] The water-containing blast furnace gas enters the dehydration section 2 and is dehydrated by the dehydration system to form cold-dried blast furnace gas;

[0072] The cold dry blast furnace gas enters the reheating section 3 and is heated by the heating system to form hot dry blast furnace gas.

[0073] Through the above embodiments, the present application has the following beneficial effects or advantages:

[0074] 1) The dehydration section 2 in the blast furnace gas treatment system can remove moisture from the water-containing blast furnace gas, so that the water-containing blast furnace gas forms cold dry blast furnace gas, and then the cold dry blast furnace gas is heated through the reheating section 3 to form hot dry blast furnace gas. When the hot dry blast furnace gas is burned in an industrial furnace, a low-energy combustion process is achieved due to the reduction in the degree of moisture contained in the hot dry blast furnace gas. At the same time, the content of CO2 in the exhaust gas is also reduced, so as to achieve the purpose of energy saving and carbon reduction.

[0075] In addition, reducing the moisture in the water-containing blast furnace gas can prevent the moisture from adhering to the subsequent transmission and distribution pipelines, causing rust in the transmission and distribution pipelines, thereby increasing the service life of the pipelines and equipment.

[0076] 2) The third heat exchange system 32 in the blast furnace gas treatment system is connected to the waste heat recovery port of the iron-making area, and the hot air in the iron-making area is recovered and used to heat the cold dry blast furnace gas, which can realize the recovery and utilization of thermal energy. At the same time, the cold dry blast furnace gas is heated and sent to the industrial furnace for combustion, which can reduce the energy consumption when the industrial furnace burns blast furnace gas, so as to achieve energy-saving effect.

[0077] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0078] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A blast furnace gas treatment system, characterized in that: It comprises a dechlorination tower (1), a dehydration section (2) and a reheating section (3) which are connected in sequence; The dechlorination tower (1) is provided with a wet dechlorination system (11), and the air inlet end of the dechlorination tower (1) is connected to the air outlet end of the blast furnace gas supply system; The dehydration section (2) is provided with a dehydration system for removing moisture from the gas; The reheating section (3) is provided with a heating system for heating the gas, and the gas outlet end of the reheating section (3) is connected to the industrial furnace.

2. The blast furnace gas processing system according to claim 1, characterized in that: The dehydration section (2) comprises a dehydration tank (21) and a primary dehydrator (22), a secondary dehydrator (23) and a final dehydrator (24) for removing moisture from the gas; The primary dehydrator (22) and the final dehydrator (24) are respectively arranged at the air inlet and air outlet of the dehydration tank (21); the air outlet of the dechlorination tower (1) is connected to the air inlet of the primary dehydrator (22); and the air outlet of the final dehydrator (24) is connected to the air inlet of the reheating section (3); The intermediate dehydrator (23) is arranged in the middle of the dehydration tank (21).

3. The blast furnace gas processing system according to claim 2, characterized in that: The primary dehydrator (22) comprises a cyclone dehydrator; The air outlet end of the dechlorination tower (1) is in communication with the air inlet end of the cyclone dehydrator, the air outlet end of the cyclone dehydrator is in communication with the air inlet end of the dehydration tank (21), the height of the air inlet end of the cyclone dehydrator is greater than the height of the air outlet end of the cyclone dehydrator, and a first drain port (221) is provided at the bottom of the cyclone dehydrator.

4. The blast furnace gas processing system according to claim 2, characterized in that: The intermediate dehydrator (23) comprises a first heat exchange system (231) and a second heat exchange system (232) for reducing the temperature of the gas; The heat exchange end of the first heat exchange system (231) and the heat exchange end of the second heat exchange system (232) both extend into the interior of the dehydration tank (21), and the heat exchange end of the first heat exchange system (231) is located between the air inlet end of the dehydration tank (21) and the heat exchange end of the second heat exchange system (232).

5. The blast furnace gas processing system according to claim 4, characterized in that: The bottom of the dehydration tank (21) is provided with a second drainage port (211).

6. The blast furnace gas processing system according to claim 2, characterized in that: The final stage dehydrator (24) comprises a wire mesh demister, the shape of which matches the shape of the cross section of the dehydration tank (21), and the wire mesh demister is sealed at the gas outlet end of the dehydration tank (21).

7. The blast furnace gas processing system according to claim 1, characterized in that: The reheating section (3) comprises a reheating tank (31) and a third heat exchange system (32) for heating gas; The air inlet end of the reheating tank (31) is connected to the air outlet end of the dehydration section (2), and the air outlet end of the reheating tank (31) is connected to the industrial furnace; The heat exchange end of the third heat exchange system (32) extends to the interior of the reheating tank (31).

8. The blast furnace gas processing system according to claim 7, characterized in that: The third heat exchange system (32) is connected to the waste heat recovery port of the ironmaking area.

9. The blast furnace gas processing system according to claim 1, characterized in that: The air inlet of the dechlorination tower (1) is arranged near the bottom of the dechlorination tower (1), the air outlet of the dechlorination tower (1) is arranged at the top of the dechlorination tower (1), and the wet dechlorination system (11) is located between the air inlet of the dechlorination tower (1) and the air outlet of the dechlorination tower (1).

10. A blast furnace gas treatment process, characterized in that: The treatment process is implemented by the blast furnace gas treatment system according to any one of claims 1 to 9, and the treatment process comprises the following steps: The chlorine-containing blast furnace gas after dry dust removal is sent into the dechlorination tower (1), and is dechlorinated by the wet dechlorination system (11) to form water-saturated water-containing blast furnace gas; The water-containing blast furnace gas enters the dehydration section (2) and is dehydrated by the dehydration system to form cold-dried blast furnace gas; The cold dry blast furnace gas enters the reheating section (3) and is heated by the heating system to form hot dry blast furnace gas.

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