Denitration, desulfurization and dust removal system for industrial silicon flue gas
By using a two-stage waste heat boiler combined with SCR denitrification and SDS dry desulfurization technology in the flue gas treatment system of industrial silicon electric furnaces, the problems of high investment, large land and high energy consumption in the existing technology are solved, and efficient denitrification is achieved Desulfurization and dust removal effect, and reduce operating costs and secondary pollution.
Patent Information
- Application Number
- CN202421077421.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-17
- Publication Date
- 2025-02-25
- Estimated Expiration
- 2034-05-17
AI Technical Summary
The existing industrial silicon electric furnace flue gas treatment technology route has problems such as high investment, large area, large system resistance, high energy consumption, high maintenance costs and difficult by-product treatment, making it difficult to effectively adapt to the complex and changeable flue gas industry of industrial silicon electric furnaces. condition.
A two-stage waste heat boiler combined with SCR denitrification and SDS dry desulfurization system is adopted to achieve multi-stage heat recovery through two-stage waste heat boilers. The SCR denitrification device works at the optimal temperature to extend the catalyst life. The SDS dry desulfurization device occupies a small area. The process is simple, the desulfurizer is widely sourced and there are few by-products.
It achieves low overall investment and convenient maintenance, high denitrification and desulfurization and dust removal efficiency, and can adapt to the complex and variable flue gas working conditions of industrial silicon electric furnaces, reduce operating costs and reduce secondary pollution.
Smart Images
Figure CN222518250U_ABST
Abstract
Description
[Technical field]
[0001] The utility model relates to the technical field of comprehensive treatment of industrial silicon electric furnace flue gas, in particular to an industrial silicon flue gas denitration, desulfurization and dust removal system. [Background technology]
[0002] Since the use of charcoal is currently restricted in industrial silicon production, most companies use petroleum coke, clean coal, etc. as reducing agents. During the electric furnace smelting process, the reducing agent reacts with the raw silica with a SiO2 content of not less than 99%, and SiO2 is reduced to Si by C at high temperature. The industrial silicon electric furnace production process is cyclical. During different processes, the flue gas volume, flue gas temperature and particulate matter content continue to change and fluctuate greatly. The particulate matter mainly contains SiO2. Due to the use of petroleum coke, clean coal, etc., the flue gas also contains SO2 and NOx.
[0003] The published group standard "Emission Standards for Air Pollutants in Industrial Silicon Production" T / CNIA0123-2021 stipulates the emission concentration limits of particulate matter, SO2 and NOx for existing and newly built enterprises. At the same time, due to the tightening of environmental protection policies, the total amount of pollutant emissions of enterprises and the internal conventions of the industrial silicon industry, some enterprises have added desulfurization and denitrification equipment, and the emission indicators are also close to the ultra-low emission indicators of the power industry or other non-power industries. Due to the influence of the flue gas characteristics of industrial silicon electric furnaces, the application of various desulfurization, denitrification and dust removal technical routes is subject to varying degrees of restrictions. At present, the mainstream technical routes in the domestic industrial silicon electric furnace flue gas treatment projects are: 1. Waste heat boiler + bag dust removal + circulating fluidized bed desulfurization + bag dust removal + SCR denitrification; 2. Waste heat boiler + bag dust removal + SCR denitrification + spray semi-dry desulfurization + flue gas dust collection device; 3. Waste heat boiler + bag dust removal + ozone denitrification + wet desulfurization.
[0004] When adopting the technical route of waste heat boiler + bag dust removal + circulating fluidized bed desulfurization + bag dust removal + SCR denitrification, the concentration of particulate matter at the outlet of the fluidized bed desulfurization tower is high, and a high-efficiency bag dust collector needs to be arranged downstream to ensure that the particulate matter meets the emission standards, which occupies a large area; the system resistance is large, and the energy consumption of the induced draft fan is too high; the desulfurization by-product contains a large amount of calcium sulfite, which is difficult to utilize comprehensively; the investment is high, and the circulating fluidized bed design is complex.
[0005] When adopting the technical route of waste heat boiler + bag dust removal + SCR denitrification + spray semi-dry desulfurization + flue gas dust collection device, the overall footprint and system resistance are equivalent to the above-mentioned circulating fluidized bed desulfurization technical route, and it also faces the problem of handling desulfurization ash containing calcium sulfite; key equipment such as SDA atomizers rely on imports, pipes and nozzles are prone to blockage, and investment and maintenance costs are high; semi-dry desulfurization towers will produce solid deposits.
[0006] When adopting the technical route of waste heat boiler + bag dust removal + ozone denitrification + wet flue gas desulfurization, the use of water will inevitably produce wastewater and corrosion problems, which need to be treated accordingly; it contains by-products such as waste residue, which will cause secondary pollution to the environment; when the NOx content is high, the investment cost of ozone denitrification is high; the system is complex, the energy consumption is high, and the area occupied is large; it is difficult to transform existing projects using this technical route. [Contents of the utility model]
[0007] The purpose of the utility model is to solve the problems in the prior art and to propose an industrial silicon flue gas denitrification, desulfurization and dust removal system, which has low overall investment, convenient maintenance, high denitrification, desulfurization and dust removal efficiency, and can adapt to the complex and changeable flue gas conditions of industrial silicon electric furnaces.
[0008] To achieve the above purpose, the utility model proposes an industrial silicon flue gas denitrification, desulfurization and dust removal system, including a flue, a high-temperature waste heat boiler, an SCR denitrification device, a medium-temperature waste heat boiler, an SDS dry desulfurization device, a bag dust removal device and a chimney connected in sequence.
[0009] Preferably, the SDS dry desulfurization device comprises a material storage and grinding module, a material unloading module, a material injection module and a dry reaction module which are connected in sequence. The desulfurizer in the material storage and grinding module enters the material injection module through the material unloading module, and then is sprayed out from the material injection module to contact the flue gas, and then enters the dry reaction module with the flue gas for sufficient mixing and reaction to complete the removal of SO2.
[0010] Preferably, a Venturi section is provided at the inlet area below the dry reaction module, and the diameter of the Venturi section is 55%-85% of the diameter of the reaction zone above the dry reaction module.
[0011] Preferably, the bag dust removal device comprises a dust collector body and an ash unloading fine screening module arranged at the bottom of the dust collector body.
[0012] Preferably, a catalyst reservation layer and a catalyst operation layer are provided in the SCR denitration device.
[0013] Beneficial effects of the utility model: The utility model realizes multi-stage heat recovery through a two-stage waste heat boiler, so that the downstream equipment can reach a suitable reaction temperature. The SCR denitrification catalyst reacts at the optimal temperature, which prolongs the service life and reduces the operating cost. The SDS dry desulfurization occupies a small area, the process technology is simple and practical, and the operation is stable. The desulfurizer is widely available, low in price, has few by-products and a high sodium sulfate content, and is easy to use. The overall waterless operation avoids corrosion of equipment and chimneys. The recovery of microsilicon powder improves the efficiency of the enterprise and reduces secondary pollution. Compared with the existing technology, it can reduce overall investment, is easy to maintain, has a higher denitrification, desulfurization and dust removal efficiency, and can adapt to the complex and changeable flue gas conditions of industrial silicon electric furnaces.
[0014] The features and advantages of the present invention will be described in detail through embodiments in conjunction with the accompanying drawings.
Brief Description of the Drawings
[0015] Figure 1 The utility model is a structural schematic diagram of an industrial silicon flue gas denitration, desulfurization and dust removal system.
[0016] In the figure: 1-flue, 2-high temperature waste heat boiler, 3-SCR denitrification device, 4-medium temperature waste heat boiler, 5-SDS dry desulfurization device, 6-bag dust removal device, 7-chimney, 51-material storage and grinding module, 52-material unloading module, 53-material injection module, 54-dry reaction module, 61-dust collector body, 62-ash unloading and fine screening module. [Specific implementation method]
[0017] See also Figure 1 The utility model discloses an industrial silicon flue gas denitration, desulfurization and dust removal system, comprising a flue 1, a high-temperature waste heat boiler 2, an SCR denitration device 3, a medium-temperature waste heat boiler 4, an SDS dry desulfurization device 5, a bag dust removal device 6 and a chimney 7 which are connected in sequence.
[0018] The SDS dry desulfurization device 5 includes a material storage and grinding module 51, a material unloading module 52, a material injection module 53 and a dry reaction module 54 which are connected in sequence. The desulfurizer in the material storage and grinding module 51 enters the material injection module 53 through the material unloading module 52, and then is sprayed out from the material injection module 53 to contact the flue gas, and then enters the dry reaction module 54 with the flue gas to be fully mixed and reacted to complete the removal of SO2.
[0019] A venturi section is arranged at the inlet area below the dry reaction module 54 , and the diameter of the venturi section is 55%-85% of the diameter of the reaction area above the dry reaction module 54 .
[0020] The bag dust removal device 6 includes a dust collector body 61 and a dust removal and fine screening module 62 arranged at the bottom of the dust collector body 61 .
[0021] The SCR denitration device 3 is provided with a catalyst reserve layer and a catalyst operation layer.
[0022] Working process of this utility model:
[0023] In the working process of the industrial silicon flue gas denitration, desulfurization and dust removal system of the utility model, the pollutant-containing flue gas in the flue 1 first enters the high-temperature waste heat boiler 2, and is cooled from 500-600°C to 300-400°C, reaching the optimal reaction temperature of SCR denitration. The SCR denitration device 3 is arranged between the high-temperature waste heat boiler 2 and the medium-temperature waste heat boiler 4, and the removal of NOx is completed after the flue gas enters. The flue gas after denitration enters the medium-temperature waste heat boiler 4, and is cooled from 300-400°C to 130-200°C, reaching the suitable reaction temperature of SDS dry desulfurization. The SDS dry desulfurization device 5 includes a material storage and grinding module 51, a material unloading module 52, a material injection module 53 and a dry reaction module 54. The desulfurizer in the material storage and grinding module 51 contacts the flue gas through the material unloading 52 and the material injection module 53 in turn, and enters the dry reaction module 54 with the flue gas to fully mix and react, and complete the removal of SO2. The bag dust removal device 6 is arranged between the SDS dry desulfurization device 5 and the chimney 7, and includes a dust collector body 61 and an ash removal fine screening module 62. After the denitrification and desulfurization flue gas enters the dust collector body 61, the particles will fall into the ash removal fine screening module 62 under the action of gravity or the vibration action of the dust collector body 61, completing the removal of useless particles and the fine screening recovery of microsilica powder. After the flue gas removes the particles, it is finally discharged into the atmosphere through the chimney 7.
[0024] The SCR denitration device 3 uses ammonia water or urea as a reducing agent.
[0025] The material storage and grinding module 51 is used for storing and grinding the desulfurizing agent, and the desulfurizing agent is sodium bicarbonate or highly active sodium carbonate.
[0026] The above embodiments are intended to illustrate the present invention, not to limit the present invention. Any solution that is a simple transformation of the present invention falls within the protection scope of the present invention.
Claims
1. An industrial silicon flue gas denitrification, desulfurization and dust removal system, characterized by: It comprises a flue (1), a high-temperature waste heat boiler (2), an SCR denitrification device (3), a medium-temperature waste heat boiler (4), an SDS dry desulfurization device (5), a bag dust removal device (6) and a chimney (7) which are connected in sequence.
2. The industrial silicon flue gas denitrification, desulfurization and dust removal system according to claim 1, characterized in that: The SDS dry desulfurization device (5) comprises a material storage and grinding module (51), a material unloading module (52), a material injection module (53) and a dry reaction module (54) which are connected in sequence. The desulfurization agent in the material storage and grinding module (51) enters the material injection module (53) through the material unloading module (52), and then is sprayed out from the material injection module (53) to contact with the flue gas, and then enters the dry reaction module (54) with the flue gas to fully mix and react, thereby completing the removal of SO2.
3. An industrial silicon flue gas denitrification, desulfurization and dust removal system as claimed in claim 2, characterized in that: A venturi section is arranged at the inlet area below the dry reaction module (54), and the diameter of the venturi section is 55%-85% of the diameter of the reaction area above the dry reaction module (54).
4. The industrial silicon flue gas denitrification, desulfurization and dust removal system according to claim 1, characterized in that: The bag dust removal device (6) comprises a dust collector body (61) and a dust removal fine screening module (62) arranged at the bottom of the dust collector body (61).
5. An industrial silicon flue gas denitrification, desulfurization and dust removal system according to any one of claims 1 to 4, characterized in that: The SCR denitration device (3) is provided with a catalyst reserve layer and a catalyst operation layer.