Integrated flue gas desulfurization and denitrification system for coke oven

Abstract

This utility model belongs to the field of coke oven flue gas purification technology, specifically relating to an integrated desulfurization and denitrification treatment system for coke oven flue gas. It includes an exhaust chimney and an integrated desulfurization and denitrification tower. The raw flue gas output of the coke oven is connected to the raw flue gas inlet of the integrated desulfurization and denitrification tower, and the clean flue gas outlet of the integrated desulfurization and denitrification tower is connected to the exhaust chimney via an induced draft fan. This utility model, by adding an integrated desulfurization and denitrification tower, eliminates the need for external pipelines connecting the desulfurization and denitrification sections, saving space and avoiding temperature drops during flue gas transmission outside the tower, thus reducing equipment and energy costs.

Description

Technical Field

[0001] This utility model belongs to the field of coke oven flue gas purification technology, specifically relating to an integrated desulfurization and denitrification treatment system for coke oven flue gas. Background Technology

[0002] Coke ovens are core equipment in the steel and coal chemical industries. During the coking process, they produce a large amount of complex flue gas. Nitrogen oxides are the pollutant with the highest proportion in coke oven flue gas. Traditional treatment methods often use SCR denitrification reactors to denitrify the coke oven flue gas before it is discharged.

[0003] If desulfurization is not performed and denitrification is performed directly, the sulfur dioxide in the flue gas will react with the reducing agent ammonia to form ammonium sulfate, which will block the catalyst pores. Therefore, strict desulfurization and denitrification treatment of the flue gas is required.

[0004] Existing desulfurization and denitrification equipment is mostly set up independently, requiring additional flue gas conveying pipelines, diversion valves and supporting structures, etc., and occupies a large area, resulting in high equipment purchase and civil engineering investment costs. In addition, the flue gas needs to pass through a long pipeline during the process of being transferred from the desulfurization equipment to the denitrification equipment. This process causes the temperature of the flue gas to drop, and it needs to be reheated before entering the denitrification equipment for denitrification, resulting in additional energy costs. Utility Model Content

[0005] To address the problems existing in the prior art, this utility model provides an integrated desulfurization and denitrification treatment system for coke oven flue gas. By adding an integrated desulfurization and denitrification tower, there is no need for external pipelines to connect the desulfurization section and the denitrification section, saving space and avoiding temperature drop of flue gas during transmission outside the tower, thereby reducing equipment and energy costs.

[0006] The specific technical solution adopted in this utility model is as follows:

[0007] An integrated desulfurization and denitrification treatment system for coke oven flue gas includes an exhaust chimney and an integrated desulfurization and denitrification tower. The raw flue gas output end of the coke oven is connected to the raw flue gas inlet of the integrated desulfurization and denitrification tower, and the clean flue gas outlet of the integrated desulfurization and denitrification tower is connected to the exhaust chimney via an induced draft fan.

[0008] A heat exchanger is also installed between the desulfurization and denitrification integrated tower and the exhaust chimney. The clean flue gas outlet of the desulfurization and denitrification integrated tower is connected to the shell-side input end of the heat exchanger, and the shell-side output end of the heat exchanger is connected to the input end of the induced draft fan.

[0009] The integrated desulfurization and denitrification tower includes a desulfurization section located in the lower half of the tower body and a denitrification section located in the upper half of the tower body. The desulfurization section and the denitrification section are connected by a mixed flow section. The raw flue gas inlet of the integrated desulfurization and denitrification tower is located at the bottom of the desulfurization section, and the clean flue gas outlet of the integrated desulfurization and denitrification tower is located at the top of the denitrification section.

[0010] The desulfurization section includes a desulfurizing agent packing layer and partition plates. The desulfurizing agent packing layer has a vertical plate-like structure, and multiple sets of the desulfurizing agent packing layer are spaced apart in the horizontal direction. Multiple sets of partition plates are spaced apart in the vertical direction, and a desulfurization channel is formed between adjacent partition plates. The desulfurizing agent packing layer passes through multiple stages of the desulfurization channel in sequence in the vertical direction and is supported and fixed by the partition plates. The output end of the raw flue gas inlet is connected to the first-stage desulfurization channel at the bottom. The raw flue gas passes through the previous stage desulfurization channel from one side of the tower body and enters the next stage desulfurization channel from the other side of the tower body through a U-shaped duct.

[0011] A desulfurization distributor is also provided at the top of the desulfurization section. The desulfurization distributor is provided with desulfurization distribution holes. The diameter of the desulfurization distribution holes increases from one side of the flue gas inlet end of the final desulfurization channel to the other side.

[0012] The output end of the U-shaped conduit has a funnel-shaped structure, with the wider side of the funnel-shaped structure facing the desulfurization channel.

[0013] The denitrification section includes a horizontally arranged denitrification agent packing layer, and multiple sets of the denitrification agent packing layer are arranged at intervals along the vertical direction. The desulfurization flue gas passes through multiple sets of denitrification agent packing layers from bottom to top.

[0014] The mixed flow section includes a grid plate, a denitrification distributor, and an ammonia inlet located between the two. A mixed flow space is formed between the grid plate and the denitrification distributor. The desulfurization flue gas enters the mixed flow space along the grid plate and mixes with the ammonia to form a mixed gas. The mixed gas is evenly distributed into the denitrification section by means of the denitrification distributor.

[0015] The denitrification distributor is provided with denitrification distribution holes, and the diameter of the denitrification distribution holes increases from the center to the periphery.

[0016] The mixing section is also equipped with a dilution gas inlet, which is symmetrically arranged with the ammonia inlet. The clean flue gas from the outlet side of the denitrification section is led to the dilution gas inlet by a dilution fan and the ammonia is diluted.

[0017] The beneficial effects of this utility model are:

[0018] 1. This utility model adds an integrated desulfurization and denitrification tower, allowing the raw flue gas from the coke oven to first enter the integrated desulfurization and denitrification tower for desulfurization and denitrification treatment. The raw flue gas undergoes desulfurization in the integrated desulfurization and denitrification tower first, and then undergoes denitrification once, avoiding the problem of sulfur dioxide entering the denitrification section and reacting with ammonia to generate ammonium sulfate that clogs the catalyst. At the same time, the integrated desulfurization and denitrification tower integrates the desulfurization and denitrification pretreatment functions, replacing the independent distribution of traditional desulfurization equipment and denitrification tower equipment, reducing additional pipeline connections, diversion valves and support structures, and other components, thus reducing the footprint. Moreover, the flue gas does not need to be transported over long distances between the desulfurization and denitrification equipment, significantly reducing temperature drop losses and lowering the reheat load of the heating furnace.

[0019] 2. The structure of the integrated desulfurization and denitrification tower in this utility model allows the flue gas to flow continuously from bottom to top inside the tower, eliminating the need for external pipelines to connect the desulfurization and denitrification sections. This saves space and avoids temperature drop of the flue gas during transmission outside the tower. At the same time, the mixing section can perform flow equalization pretreatment on the desulfurized flue gas, ensuring the uniformity of the subsequent denitrification reaction. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the system of this utility model;

[0021] Figure 2 This is a schematic diagram of the integrated desulfurization and denitrification tower.

[0022] Figure 3 This is a schematic diagram of the desulfurization distributor.

[0023] Figure 4 This is a schematic diagram of the denitrification distributor;

[0024] In the attached diagram, 1 is the tower body, 2 is the raw flue gas inlet, 3 is the clean flue gas outlet, 4 is the desulfurizing agent packing layer, 5 is the partition plate, 6 is the U-shaped duct, 7 is the desulfurization distributor, 8 is the desulfurization distribution hole, 9 is the denitrification agent packing layer, 10 is the grid plate, 11 is the denitrification distributor, 12 is the ammonia inlet, 13 is the denitrification distribution hole, 14 is the dilution gas inlet, and 15 is the dilution fan. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0026] Specific embodiments, such as Figure 1 As shown, this utility model provides an integrated desulfurization and denitrification treatment system for coke oven flue gas, including an exhaust chimney and an integrated desulfurization and denitrification tower. The raw flue gas output end of the coke oven is connected to the raw flue gas inlet 2 of the integrated desulfurization and denitrification tower, and the clean flue gas outlet 3 of the integrated desulfurization and denitrification tower is connected to the exhaust chimney by means of an induced draft fan.

[0027] Existing desulfurization and denitrification equipment is mostly set up independently, requiring additional flue gas conveying pipelines, diversion valves and supporting structures, etc., and occupies a large area, resulting in high equipment purchase and civil engineering investment costs. In addition, the flue gas needs to pass through a long pipeline during the process of being transferred from the desulfurization equipment to the denitrification equipment. This process causes the temperature of the flue gas to drop, and it needs to be reheated before entering the denitrification equipment for denitrification, resulting in additional energy costs.

[0028] This invention adds an integrated desulfurization and denitrification tower, allowing the raw flue gas from the coke oven to first enter the integrated tower for desulfurization and denitrification treatment. The raw flue gas undergoes desulfurization in the integrated tower first, and then undergoes denitrification once, avoiding the problem of sulfur dioxide reacting with ammonia in the denitrification section to form ammonium sulfate that clogs the catalyst. At the same time, the integrated desulfurization and denitrification tower integrates the desulfurization and denitrification pretreatment functions, replacing the independent distribution of traditional desulfurization equipment and denitrification tower equipment, reducing additional pipeline connections, diversion valves and support structures, and reducing the footprint. Moreover, the flue gas does not need to be transported over long distances between the desulfurization and denitrification equipment, significantly reducing temperature drop losses and lowering the reheat load of the heating furnace.

[0029] like Figure 1 As shown, a heat exchanger is also installed between the desulfurization and denitrification integrated tower and the exhaust chimney. The clean flue gas outlet 3 of the desulfurization and denitrification integrated tower is connected to the shell-side input end of the heat exchanger, and the shell-side output end of the heat exchanger is connected to the input end of the induced draft fan.

[0030] Since the clean flue gas contains a high amount of residual heat and it is necessary to avoid releasing high-temperature gas into the atmosphere, this invention also includes a heat exchanger to cool the clean flue gas using a cooling medium and recover the heat.

[0031] like Figure 2 As shown, the integrated desulfurization and denitrification tower includes a desulfurization section located in the lower half of the tower body 1 and a denitrification section located in the upper half of the tower body 1. The desulfurization section and the denitrification section are connected by a mixed flow section. The raw flue gas inlet 2 of the integrated desulfurization and denitrification tower is located at the bottom of the desulfurization section, and the clean flue gas outlet 3 of the integrated desulfurization and denitrification tower is located at the top of the denitrification section.

[0032] The structure of the integrated desulfurization and denitrification tower allows the flue gas to flow continuously from bottom to top inside the tower, eliminating the need for external pipelines to connect the desulfurization and denitrification sections. This saves space and avoids temperature drops caused by the flue gas being transported outside the tower body. At the same time, the mixing section can perform flow equalization pretreatment on the desulfurized flue gas, ensuring the uniformity of the subsequent denitrification reaction.

[0033] like Figure 2As shown, the desulfurization section includes a desulfurizing agent packing layer 4 and a partition plate 5. The desulfurizing agent packing layer 4 has a vertical plate-like structure and multiple sets of desulfurizing agent packing layers 4 are spaced apart in the horizontal direction. Multiple sets of partition plates 5 are spaced apart in the vertical direction, and a desulfurization channel is formed between adjacent partition plates 5. The desulfurizing agent packing layer 4 passes through multiple desulfurization channels in the vertical direction and is supported and fixed by the partition plates 5. The output end of the raw flue gas inlet 2 is connected to the first-stage desulfurization channel at the bottom. The raw flue gas passes through the previous stage desulfurization channel from one side of the tower body 1 and enters the next stage desulfurization channel from the other side of the tower body 1 through the U-shaped conduit 6.

[0034] The desulfurization section forms a multi-stage desulfurization channel through the partition plate 5, and together with the U-shaped duct 6, the flue gas forms an S-shaped flow, allowing the flue gas to pass through each desulfurizing agent packing layer 4 multiple times, so that the flue gas and the desulfurizing agent packing layer 4 can fully contact each other, prolong the reaction time, and ensure that sulfur dioxide in the flue gas is removed.

[0035] like Figure 2-3 As shown, a desulfurization distributor 7 is also provided at the top of the desulfurization section. The desulfurization distributor 7 is provided with desulfurization distribution holes 8. The diameter of the desulfurization distribution holes 8 increases from one side of the flue gas inlet end of the final desulfurization channel to the other side.

[0036] Because the flue gas flows from one side of the tower body 1 to the other side under the action of the U-shaped duct 6, and the flue gas in the final desulfurization pipeline will be discharged from the desulfurization section and enter the mixing section, this results in the flue gas concentration being high and the flow rate being fast at the input end of the final desulfurization pipeline, while the flue gas concentration being low and the flow rate being slow at the other end, thus causing uneven distribution of flue gas in the mixing section and affecting the mixing effect of flue gas and ammonia.

[0037] Therefore, the aperture of the desulfurization distribution hole 8 is designed to increase progressively to ensure that the flue gas flow rate entering the mixing section in each area is approximately the same, which is beneficial to the subsequent mixing effect of flue gas and ammonia, thereby improving the subsequent denitrification effect.

[0038] like Figure 2 As shown, the output end of the U-shaped conduit 6 has a funnel-shaped structure, with the wider side of the funnel-shaped structure facing the desulfurization channel.

[0039] The output end of the U-shaped duct 6, which has a funnel-shaped opening, can disperse the concentrated flue gas and evenly guide it into the next stage of desulfurization channel, avoiding local accumulation of flue gas or excessive flow velocity in the channel, ensuring uniform contact between the flue gas and the desulfurization packing layer, and improving the desulfurization effect.

[0040] like Figure 2 As shown, the denitrification section includes a denitrification agent packing layer 9 arranged horizontally, and multiple sets of the denitrification agent packing layer 9 are arranged at intervals along the vertical direction. The desulfurization flue gas passes through multiple sets of denitrification agent packing layers 9 from bottom to top.

[0041] By setting up multi-stage denitrification agent packing layers 9, the flue gas passes through each denitrification agent packing layer 9 sequentially from bottom to top, achieving a full reaction between the flue gas and the denitrification catalyst, extending the contact time between nitrogen oxides and the denitrification catalyst, and avoiding the problem of insufficient reaction caused by a single denitrification agent packing layer 9.

[0042] like Figure 2 As shown, the mixed flow section includes a grid plate 10, a denitrification distributor 11, and an ammonia inlet 12 located between the two. A mixed flow space is formed between the grid plate 10 and the denitrification distributor 11. The desulfurization flue gas enters the mixed flow space along the grid plate 10 and mixes with the ammonia to form a mixed gas. The mixed gas is evenly distributed into the denitrification section by means of the denitrification distributor 11.

[0043] Ammonia, as a reducing agent in the denitrification reaction process, needs to be uniformly mixed with flue gas. Therefore, this invention is equipped with a mixing section to ensure that ammonia is uniformly mixed with the desulfurized flue gas and to avoid the problem of excessive or insufficient ammonia in some areas.

[0044] like Figure 2 As shown, a dilution gas inlet 14 is also provided on the mixed flow section. The dilution gas inlet 14 and the ammonia inlet 12 are arranged symmetrically on the left and right. The clean flue gas on the outlet side of the denitrification section is led to the dilution gas inlet 14 by the dilution fan 15 and the ammonia is diluted.

[0045] First, it is necessary to control the ammonia concentration to avoid the risk of explosion caused by excessive ammonia concentration. Therefore, the clean flue gas is reintroduced into the mixed flow space to dilute the ammonia.

[0046] Secondly, the symmetrical arrangement of the dilution gas inlet 14 and the ammonia inlet 12 will cause the ammonia and the clean flue gas to collide, thereby forming turbulent mixing and improving the uniformity of mixing. At the same time, the turbulence will also disturb the desulfurization flue gas entering the mixing space, so that it is mixed evenly with the ammonia.

[0047] like Figure 2 and Figure 4 As shown, the denitrification distributor 11 is provided with denitrification distribution holes 13, and the diameter of the denitrification distribution holes 13 increases from the center to the periphery.

[0048] Due to the effect of turbulent mixing, the mixed gas is concentrated in the central region of the mixing space. When the mixed gas rises to the denitrification section, it will cause the catalyst in the center of the denitrification agent packing layer 9 to be over-consumed and the catalyst on the periphery to not react fully.

[0049] Therefore, this utility model also includes a denitrification distributor 11. The diameter of the denitrification distribution hole 13 is designed to increase from the center to the periphery. The diameter of the denitrification distribution hole 13 at the center is smaller, so the mixed gas concentrated at the center cannot pass through the denitrification distribution hole 13 in large quantities. Therefore, it will disperse to the periphery to ensure that the flow rate of the mixed gas entering the denitrification section in each area is approximately the same.

Claims

1. An integrated desulfurization and denitrification treatment system for coke oven flue gas, comprising an exhaust chimney, characterized in that, It also includes a desulfurization and denitrification integrated tower. The original flue gas output end of the coke oven is connected to the original flue gas inlet (2) of the desulfurization and denitrification integrated tower, and the clean flue gas outlet (3) of the desulfurization and denitrification integrated tower is connected to the exhaust chimney by means of an induced draft fan.

2. The integrated desulfurization and denitrification system for coke oven flue gas according to claim 1, characterized in that, A heat exchanger is also provided between the desulfurization and denitrification integrated tower and the exhaust chimney. The clean flue gas outlet (3) of the desulfurization and denitrification integrated tower is connected to the shell-side input end of the heat exchanger, and the shell-side output end of the heat exchanger is connected to the input end of the induced draft fan.

3. The integrated desulfurization and denitrification treatment system for coke oven flue gas according to claim 1, characterized in that, The desulfurization and denitrification integrated tower includes a desulfurization section located in the lower half of the tower body (1) and a denitrification section located in the upper half of the tower body (1). The desulfurization section and the denitrification section are connected by a mixed flow section. The raw flue gas inlet (2) of the desulfurization and denitrification integrated tower is located at the bottom of the desulfurization section, and the clean flue gas outlet (3) of the desulfurization and denitrification integrated tower is located at the top of the denitrification section.

4. The integrated desulfurization and denitrification system for coke oven flue gas according to claim 3, characterized in that, The desulfurization section includes a desulfurizing agent packing layer (4) and a partition plate (5). The desulfurizing agent packing layer (4) has a vertical plate structure. Multiple sets of desulfurizing agent packing layers (4) are spaced apart in the horizontal direction. Multiple sets of partition plates (5) are spaced apart in the vertical direction. A desulfurization channel is formed between adjacent partition plates (5). The desulfurizing agent packing layer (4) passes through multiple desulfurization channels in the vertical direction and is supported and fixed by the partition plates (5). The output end of the raw flue gas inlet (2) is connected to the first-stage desulfurization channel at the bottom. The raw flue gas passes through the previous desulfurization channel from one side of the tower body (1) and enters the next desulfurization channel from the other side of the tower body (1) through a U-shaped conduit (6).

5. The integrated desulfurization and denitrification system for coke oven flue gas according to claim 4, characterized in that, The top of the desulfurization section is also provided with a desulfurization distributor (7), and the desulfurization distributor (7) is provided with a desulfurization distribution hole (8). The diameter of the desulfurization distribution hole (8) increases from one side of the flue gas input end of the final desulfurization channel to the other side.

6. The integrated desulfurization and denitrification system for coke oven flue gas according to claim 4, characterized in that, The output end of the U-shaped conduit (6) has a funnel-shaped structure, with the wider side of the funnel-shaped structure facing the desulfurization channel.

7. The integrated desulfurization and denitrification system for coke oven flue gas according to claim 3, characterized in that, The denitrification section includes a denitrification agent packing layer (9) arranged horizontally, and multiple sets of the denitrification agent packing layer (9) are arranged at intervals in the vertical direction. The desulfurization flue gas passes through multiple sets of denitrification agent packing layers (9) from bottom to top.

8. The integrated desulfurization and denitrification system for coke oven flue gas according to claim 3, characterized in that, The mixed flow section includes a grid plate (10), a denitrification distributor (11), and an ammonia inlet (12) located between the two. A mixed flow space is formed between the grid plate (10) and the denitrification distributor (11). The desulfurized flue gas enters the mixed flow space along the grid plate (10) and mixes with the ammonia to form a mixed gas. The mixed gas is evenly distributed into the denitrification section by means of the denitrification distributor (11).

9. The integrated desulfurization and denitrification system for coke oven flue gas according to claim 8, characterized in that, The denitrification distributor (11) is provided with denitrification distribution holes (13), and the diameter of the denitrification distribution holes (13) increases from the center to the periphery.

10. The integrated desulfurization and denitrification system for coke oven flue gas according to claim 8, characterized in that, The mixing section is also provided with a dilution gas inlet (14), which is symmetrically arranged with the ammonia inlet (12). The clean flue gas from the outlet side of the denitrification section is led to the dilution gas inlet (14) by means of a dilution fan (15) and the ammonia is diluted.

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