Flue gas denitration device of walking beam furnace
The step-in step-out furnace NOx removal system uses bioliquid reductants with controlled injection to address inefficiencies and costs, achieving efficient and stable NOx removal across varying conditions.
Patent Information
- Application Number
- CN202422231488.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-12
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2034-09-12
AI Technical Summary
The existing heating furnace has low flue gas denitrification efficiency, large footprint, high cost and poor effect, making it difficult to maintain good denitrification efficiency under complex working conditions, and the SCR device covers a large footprint, has high investment and high operating costs, and the stepper heating furnace cannot maintain a micro positive pressure.
The online dilution system is used to combine a denitrifier storage tank and a desalinate tank. Through the PLC-controlled denitrifier distribution cabinet, atomized spray guns spray denitrifiers in different temperature ranges, combined with the temperature control of the rising flue and heat recovery section, the automatic adjustment of the denitrifier is achieved.
Under complex working conditions, efficient denitrification is achieved, flue gas emissions meet standards, simple system and convenient operation, saving land and cost, not affecting production, and denitrification efficiency reaches more than 80%.
Smart Images
Figure CN223096535U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of flue gas denitration systems, and in particular relates to a flue gas denitration device for a walking-beam heating furnace. Background Art
[0002] According to the ultra-low emission requirements of the steel industry, the nitrogen oxide concentration in the flue gas emissions of heating furnaces is required to be less than 200mg / Nm³. Most companies use mixed fuels such as blast furnace gas, coke oven gas, and natural gas as heating furnace fuels. Blast furnace gas and coke oven gas are not treated at the source, resulting in heating furnace flue gas emissions that do not meet environmental standards, and the nitrogen oxide concentration can reach up to 600mg / Nm³ or more.
[0003] The heating furnace needs to process different types of steel, and the working conditions are complex. The flue gas temperature fluctuates greatly between 570 and 850°C. The SNCR process does not have a suitable temperature range and its efficiency is too low. The SCR investment is high, the floor space is large, the operating cost is high, and the SCR reactor will increase the system resistance, and it is necessary to add an induced draft fan, which will increase energy consumption. However, in order to ensure the temperature field in the furnace, the walking-beam heating furnace needs to maintain a slight positive pressure in the furnace and exhaust smoke naturally at the tail. After adding the induced draft fan, it cannot be matched with the blower in real time, and it is difficult to ensure a slight positive pressure in the furnace, which increases the gas consumption and the production cost. In addition, some companies did not reserve space for denitrification equipment in their initial planning, and could not install a denitrification equipment that occupies a large area. Utility Model Content
[0004] The purpose of the utility model is to solve the problems of low denitration efficiency, large space, high cost and poor effect of the existing heating furnace flue gas denitration, and to provide a walking type heating furnace flue gas denitration device, so that the heating furnace can have a good denitration efficiency under various complex working conditions, ensure that the flue gas meets the emission standards, is easy to operate, runs stably, and saves space and economic costs.
[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:
[0006] A walking-beam heating furnace flue gas denitration device comprises a denitrification agent storage tank and a denitrification water tank which cooperate with each other, wherein the denitrification agent storage tank is connected to the inlet of the denitrification agent distribution cabinet through a first pipeline, and the first pipeline is sequentially connected with a denitrification agent delivery pump and a denitrification agent regulating valve, and the denitrification water tank is also connected to the inlet of the denitrification agent distribution cabinet through a second pipeline, and the second pipeline is sequentially connected with a denitrification water delivery pump and a denitrification water regulating valve;
[0007] The denitrification agent distribution cabinet is also connected to a compressed air input pipe, the outlet of the denitrification agent distribution cabinet is connected to a pipe three, the ends of the pipe three are respectively connected to a branch pipe one and a branch pipe two, the branch pipe one is connected to an ascending flue denitrification agent control valve and its end is connected to a group of atomizing spray guns one, the atomizing spray guns one is arranged in the ascending flue of the heating furnace, the branch pipe two is connected to a heat recovery section denitrification agent control valve and its end is connected to a group of atomizing spray guns two, the atomizing spray guns two are arranged in the heat recovery section of the heating furnace;
[0008] A rising flue thermocouple is also provided in the rising flue of the heating furnace. The lower part of the heating furnace is provided with a heat recovery section, a preheating section, a first heating section, a second heating section and a uniform heating section from the steel inlet end to the steel outlet end, and a heat recovery section thermocouple is provided in the heat recovery section.
[0009] Furthermore, the ascending flue denitrification agent control valve and the heat recovery section denitrification agent control valve are interlocked with the ascending flue thermocouple and the heat recovery section thermocouple respectively, and are controlled by PLC to automatically start and stop the denitrification agent control valve of each section according to the temperature measured in each section.
[0010] Furthermore, the denitrification agent in the denitrification agent storage tank is a liquid biomass denitrification agent, and the applicable temperature is 650~750℃.
[0011] Furthermore, the denitrification agent and the desalted water are diluted online through a denitrification agent regulating valve and a desalted water regulating valve, and the dilution ratio calculated by mass concentration is 1:1-1:2, and the optimal ratio is 1:1.
[0012] Furthermore, the atomizing spray gun in the ascending flue adopts a fan-shaped atomizing surface with an atomizing angle of 60°~90°.
[0013] Furthermore, the atomizing spray gun 2 of the heat recovery section adopts a fan-shaped atomizing surface with an atomizing angle of 90° to 120°.
[0014] Furthermore, the second atomizing spray gun is distributed on the top and side of the heat recovery section in the heating furnace, and the atomizing spray gun located on the top of the heating furnace is arranged in a V shape to ensure the temperature range of the denitrification agent injection point.
[0015] In the technical solution of the utility model, the denitrification agent is diluted with desalted water online to a certain concentration and evenly distributed in the appropriate temperature zone of the heating furnace to remove NO in the flue gas. x Reaction, can remove most of the NO in flue gas x According to the temperature measurement value on the flue, the denitrification agent regulating valves of the heat recovery section and the ascending flue are adjusted in real time to control the amount of denitrification agent added to each section; at the same time, the biomass denitrification agent has a lower temperature range, so that the heating furnace can have a better denitrification efficiency under various complex working conditions, ensuring that the flue gas meets the emission standards. The system of the utility model has a simple structure, convenient operation, stable operation and low investment. Description of the Drawings
[0016] Figure 1 This is a schematic structural diagram of the step-type reheating furnace flue gas denitration device of the present utility model;
[0017] Figure 2 This is a schematic diagram of the distribution of atomizing spray guns in the heat recovery section of the present utility model;
[0018] Figure 3 This is a curve graph of the 5-minute average value of nitrogen oxides CEMS before transformation in this embodiment;
[0019] Figure 4 This is a curve graph of the 5-minute average value of nitrogen oxides CEMS after transformation in this embodiment. Detailed Embodiment Embodiment
[0020] To make the present utility model more clearly understood, the following further describes a step-type reheating furnace flue gas denitration device of the present utility model with reference to the drawings. The specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.
[0021] Taking three step-type reheating furnaces on the 1780 production line of the hot rolling mill as an example, mainly heating all-series stainless steel and carbon steel, the combustion mixture gas is composed of blast furnace gas, coke oven gas, and natural gas, and the proportion of coke oven gas is 10% - 30%. The NO x concentration in the flue gas mainly changes with the amount of coke oven gas used, and can reach more than 600 mg / Nm³ at most. After denitration, the NO X emission concentration < 200 mg / Nm³. The technical indicators after transformation are as follows in the following table:
[0022]
[0023] See Figure 1 , a step-type reheating furnace flue gas denitration device, including a denitration agent storage tank 1 and a demineralized water tank 2 that cooperate with each other, and is characterized in that:
[0024] The denitration agent storage tank 1 is connected to the inlet of the denitration agent distribution cabinet 4 through pipeline 1 3, and a denitration agent transfer pump 5 and a denitration agent regulating valve 6 are successively connected on the pipeline 1 3. The demineralized water tank 2 is also connected to the inlet of the denitration agent distribution cabinet 4 through pipeline 2 7, and a demineralized water transfer pump 8 and a demineralized water regulating valve 9 are successively connected on the pipeline 2;
[0025] The denitration agent distribution cabinet 4 is also connected with a compressed air input pipe 10. The outlet of the denitration agent distribution cabinet 4 is connected with a third pipeline 11. The ends of the third pipeline 11 are respectively connected with a first branch pipe 12 and a second branch pipe 13. A rising flue denitration agent control valve 14 is connected to the first branch pipe 12 and its end is connected with a group of first atomizing spray guns 15. The first atomizing spray guns 15 are arranged in the rising flue 161 of the heating furnace 16. A heat recovery section denitration agent control valve 17 is connected to the second branch pipe 13 and its end is connected with a group of second atomizing spray guns 18. The second atomizing spray guns 18 are arranged in the heat recovery section 162 of the heating furnace 16;
[0026] A rising flue thermocouple 19 is also arranged in the rising flue 161 of the heating furnace 16. From the steel inlet end 16a to the steel outlet end 16b at the lower part of the heating furnace 16, there are successively arranged a heat recovery section 162, a preheating section 163, a first heating section 164, a second heating section 165 and a soaking section 166, and a heat recovery section thermocouple 20 is arranged in the heat recovery section 162;
[0027] The rising flue denitration agent control valve 14 and the heat recovery section denitration agent control valve 17 are respectively interlocked with the rising flue thermocouple 19 and the heat recovery section thermocouple 20, and are controlled by the PLC 21 to automatically start and stop the denitration agent control valves of each section according to the temperatures measured in each section.
[0028] See Figure 2 , the second atomizing spray guns 18 in the heat recovery section 162 adopt a fan-shaped atomizing surface, the atomizing angle is 90° - 120°, the second atomizing spray guns 18 are distributed at the top and side of the heat recovery section 162, and the atomizing spray guns located at the top of the heating furnace 16 are arranged in a V shape to ensure the temperature range of the denitration agent injection points.
[0029] See Figure 3 and Figure 4 , which are respectively the 5-minute average value curve graphs of the nitrogen oxides CEMS before and after the transformation. It can be seen that the denitration agent of the present invention is purchased from the outside world, stored in the denitration agent storage tank 1, diluted online with demineralized water to a certain concentration, and through the denitration agent distribution cabinet 4, the denitration agent is evenly distributed in the appropriate temperature zone of the heating furnace 16, reacts with the nitrogen oxides in the flue gas, and removes most of the nitrogen oxides in the flue gas. According to the temperature measurement values on the flue, the denitration agent regulating valves in the heat recovery section 162 and the rising flue 161 are adjusted to control the addition amount of the denitration agent in each section, which can effectively solve the problem of excessive nitrogen oxides in the walking beam heating furnace, is applicable to various working conditions of the heating furnace, the denitration efficiency reaches more than 80%, and the system is simple and reliable, easy to operate, low in investment, does not increase the system resistance, has no by-products, and does not affect production.
[0030] In addition to the above embodiments, the present invention can also have other implementation manners. All technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.
Claims
1. A step-type reheating furnace flue gas denitration device, comprising a denitration agent storage tank (1) and a desalted water tank (2) that cooperate with each other, and is characterized in that: The denitration agent storage tank (1) is connected to the inlet of the denitration agent distribution cabinet (4) through a first pipeline (3), and a denitration agent delivery pump (5) and a denitration agent regulating valve (6) are successively connected to the first pipeline (3). The desalted water tank (2) is also connected to the inlet of the denitration agent distribution cabinet (4) through a second pipeline (7), and a desalted water delivery pump (8) and a desalted water regulating valve (9) are successively connected to the second pipeline (7); The denitration agent distribution cabinet (4) is also connected with a compressed air input pipe (10). The outlet of the denitration agent distribution cabinet (4) is connected with a third pipeline (11). The end of the third pipeline (11) is respectively connected with a first branch pipe (12) and a second branch pipe (13). A rising flue denitration agent control valve (14) is connected to the first branch pipe (12) and its end is connected with a group of atomizing spray guns one (15). The atomizing spray gun one (15) is arranged in the rising flue (161) of the reheating furnace (16). A heat recovery section denitration agent control valve (17) is connected to the second branch pipe (13) and its end is connected with a group of atomizing spray guns two (18). The atomizing spray gun two (18) is arranged in the heat recovery section (162) of the reheating furnace (16); A rising flue thermocouple (19) is also arranged in the rising flue (161) of the reheating furnace (16). From the steel inlet end (16a) to the steel outlet end (16b) at the lower part of the reheating furnace (16), there are successively arranged a heat recovery section (162), a preheating section (163), a first heating section (164), a second heating section (165) and a soaking section (166), and a heat recovery section thermocouple (20) is arranged in the heat recovery section (162).
2. The step-type reheating furnace flue gas denitration device according to claim 1, characterized in that: The rising flue denitration agent control valve (14) and the heat recovery section denitration agent control valve (17) are respectively interlocked with the rising flue thermocouple (19) and the heat recovery section thermocouple (20), and are controlled by a PLC (21).
3. The step-type reheating furnace flue gas denitration device according to claim 1 or 2, characterized in that: The denitration agent in the denitration agent storage tank (1) is a liquid biomass denitration agent, and the applicable temperature is 650 - 750 °C.
4. The step-type reheating furnace flue gas denitration device according to claim 2, characterized in that: The denitration agent and the desalted water are diluted online through the denitration agent regulating valve (6) and the desalted water regulating valve (9). The dilution ratio calculated by mass concentration is 1:1 - 1:2, and the optimal ratio is 1:
1.
5. The step-type reheating furnace flue gas denitration device according to claim 1 or 2, characterized in that: The atomizing spray gun one (15) in the rising flue (161) adopts a fan-shaped atomizing surface, and the atomizing angle is 60° - 90°.
6. The step-type reheating furnace flue gas denitration device according to claim 1 or 2, characterized in that: The atomizing spray gun two (18) in the heat recovery section (162) adopts a fan-shaped atomizing surface, and the atomizing angle is 90° - 120°.
7. The step-type reheating furnace flue gas denitration device according to claim 1 or 2, characterized in that: The atomizing spray guns II (18) are distributed at the top and sides of the heat recovery section (162) in the heating furnace (16), and the atomizing spray guns located at the top of the heating furnace (16) are arranged in a V shape.