Industrial silicon flue gas comprehensive treatment system capable of reducing pollution and carbon

Abstract

The utility model discloses an industrial silicon flue gas comprehensive treatment system capable of reducing pollution and carbon, which comprises a flue, a waste heat boiler, an SDS (Sodium Dodecyl Sulfate) dry desulfurization device, a cloth bag dust removal device, an SCR (Selective Catalytic Reduction) denitration device, a carbon capture device and a chimney which are sequentially communicated, and the waste heat boiler is connected with the carbon capture device through a steam pipeline. A large amount of system energy consumption can be saved, the occupied area is small, the process technology is simple and practical, and operation is stable. The desulfurizer is wide in source, low in price, few in by-products, high in sodium sulfate content and convenient to use. And due to the recovery of the silica fume, the enterprise benefit is improved, and the secondary pollution is reduced. The medium and low temperature SCR denitration reduces the poisoning and blocking risks of the catalyst, prolongs the service life of the catalyst, reduces the operation cost, and can adapt to the complex and changeable flue gas working conditions of the industrial silicon electric furnace.

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 a comprehensive treatment system for industrial silicon flue gas with pollution reduction and carbon reduction. [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, NOx and CO2.

[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 stricter environmental protection policies, total constraints on corporate pollutant emissions, and internal conventions in the industrial silicon industry, some companies have added desulfurization and denitrification equipment, and emission indicators are also moving closer to ultra-low emission indicators in the power industry or other non-power industries. Industrial silicon production is accompanied by a large amount of carbon emissions. Considering the realization of the dual carbon goals in the future, it is foreseeable that the development of synergistic carbon capture technology will be gradually carried out. 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 are subject to varying degrees of restrictions. At present, the mainstream technical routes in domestic industrial silicon 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 provide an industrial silicon flue gas comprehensive treatment system for reducing pollution and carbon emissions, which can solve at least one of the above problems.

[0008] To achieve the above-mentioned purpose, the utility model proposes an industrial silicon flue gas comprehensive treatment system for reducing pollution and carbon emissions, comprising a flue, a waste heat boiler, an SDS dry desulfurization device, a bag dust removal device, an SCR denitrification device, a carbon capture device and a chimney connected in sequence, and the waste heat boiler is connected to the carbon capture device through a steam pipe.

[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, 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.

[0011] Preferably, the carbon capture device comprises a pretreatment module, an absorption module and a desorption module which are connected in sequence, the smoke exhaust port at the top of the absorption module is connected to the chimney, and the steam inlet of the desorption module is connected to the steam outlet of the waste heat boiler through a steam pipe.

[0012] Preferably, a catalyst reservation layer and a catalyst operation layer are provided in the SCR denitration device.

[0013] 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.

[0014] Beneficial effects of the utility model: The utility model can adapt to the complex and changeable flue gas conditions of industrial silicon electric furnaces. While efficiently removing conventional pollutants such as NOx, SO2 and particulate matter, it can also capture CO2 in the flue gas. The recovery of heat by the waste heat boiler not only enables the downstream equipment to reach a suitable reaction temperature, but also directly supplies the flue gas heat to the carbon capture device, saving a lot of system energy consumption. SDS dry desulfurization occupies a small area, the process technology is simple and practical, and the operation is stable. The desulfurizer is widely available, inexpensive, has few by-products and a high sodium sulfate content, and is easy to use. The recovery of microsilicon powder improves corporate benefits and reduces secondary pollution. Medium and low temperature SCR denitrification reduces the risk of catalyst poisoning and blockage, extends the service life of the catalyst, and reduces operating costs.

[0015] 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

[0016] Figure 1 The utility model is a structural schematic diagram of an industrial silicon fume comprehensive treatment system for reducing pollution and carbon.

[0017] In the figure: 1-flue, 2-waste heat boiler, 3-SDS dry desulfurization device, 4-bag dust removal device, 5-SCR denitrification device, 6-carbon capture device, 7-chimney, 8-steam pipe, 31-material storage and grinding module, 32-material unloading module, 33-material injection module, 34-dry reaction module, 61-pretreatment module, 62-absorption module, 63-desorption module. [Specific implementation method]

[0018] See also Figure 1 The utility model discloses an industrial silicon flue gas comprehensive treatment system for reducing pollution and carbon, comprising a flue 1, a waste heat boiler 2, an SDS dry desulfurization device 3, a bag dust removal device 4, an SCR denitrification device 5, a carbon capture device 6 and a chimney 7 which are connected in sequence, and the waste heat boiler 2 is connected to the carbon capture device 6 through a steam pipe 8 to supply steam thereto.

[0019] The SDS dry desulfurization device 3 includes a material storage and grinding module 31, a material unloading module 32, a material injection module 33 and a dry reaction module 34 which are connected in sequence. The desulfurizer in the material storage and grinding module 31 enters the material injection module 33 through the material unloading module 32, and then is sprayed out from the material injection module 33 to contact the flue gas, and then enters the dry reaction module 34 with the flue gas to be fully mixed and reacted to complete the removal of SO2.

[0020] The bag dust removal device 4 includes a dust collector body 41 and a dust removal and fine screening module 42 arranged at the bottom of the dust collector body 41 .

[0021] The carbon capture device 6 includes a pretreatment module 61, an absorption module 62 and a desorption module 63 which are connected in sequence. The top smoke exhaust port of the absorption module 62 is connected to the chimney 7. The steam inlet of the desorption module 63 is connected to the steam outlet of the waste heat boiler 2 through a steam pipe 8.

[0022] The SCR denitration device 5 is provided with a catalyst reserve layer and a catalyst operation layer.

[0023] A venturi section is arranged at the inlet area below the dry reaction module 34 , and the diameter of the venturi section is 55%-85% of the diameter of the reaction area above the dry reaction module 34 .

[0024] Working process of this utility model:

[0025] In the working process of the comprehensive industrial silicon flue gas treatment system for reducing pollution and carbon, the pollutant-containing flue gas in the flue 1 first enters the waste heat boiler 2, and is cooled from 500-600°C to 180-240°C to reach the suitable reaction temperature for SDS dry desulfurization. The SDS dry desulfurization device 3 is arranged between the waste heat boiler 2 and the bag dust removal device 4, and includes a material storage and grinding module 31, a material unloading module 32, a material injection module 33 and a dry reaction module 34. The desulfurizer in the material storage and grinding module 31 enters the material injection module 33 through the material unloading module 32, and then is sprayed out from the material injection module 33 to contact with the flue gas, and enters the dry reaction module 34 with the flue gas for sufficient mixing and reaction, thereby completing the removal of SO2. The bag dust removal device 4 is arranged downstream of the SDS dry desulfurization device 3, and includes a dust collector body 41 and an ash unloading fine screening module 42. After the desulfurized flue gas enters the dust collector body 41, the particulate matter will fall into the ash unloading fine screening module 42 under the action of gravity or the vibration action of the dust collector body 41, completing the removal of useless particulate matter and the fine screening recovery of microsilicon powder. The SCR denitrification device 5 is arranged between the bag dust removal device 4 and the carbon capture device 6. After the desulfurized and dust-removed flue gas enters, the NOx is removed under medium and low temperature conditions. The carbon capture device 6 is arranged downstream of the SCR denitrification device 5, including a pretreatment module 61, an absorption module 62 and a desorption module 63. The flue gas with conventional pollutants that meet the emission standards first passes through the pretreatment module 61 to complete the fine desulfurization and cool down to 40-50°C to reach the optimal reaction temperature for CO2 chemical absorption. The absorption module 52 is arranged between the pretreatment module 51 and the desorption module 53, and the internal rising flue gas reacts with the CO2 absorbent flowing downward in the countercurrent to complete the absorption of CO2. The flue gas after pollution reduction and carbon reduction is connected to the chimney 7 through the smoke exhaust port at the top of the absorption module 52, and is finally discharged into the atmosphere. The steam pipe 8 transports the steam generated by the waste heat boiler 2 to the desorption module 53 as a heat source, so that the desorption module 53 reaches the optimal desorption temperature. The CO2-rich absorbent is transported from the bottom of the absorption module 52 to the desorption module 53, completes the desorption of CO2 under high temperature conditions, and discharges high-purity CO2 for treatment.

[0026] The material storage and grinding module 31 is used for storing and grinding the desulfurization agent, and the desulfurization agent adopts sodium bicarbonate or highly active sodium carbonate.

[0027] The SCR denitration device 5 uses ammonia water or urea as a reducing agent, and a medium-low temperature catalyst is used as a catalyst.

[0028] The carbon capture device 6 includes a pretreatment module 61, an absorption module 62 and a desorption module 63. The process adopts a chemical absorption method, and the absorbent adopts an amine liquid. The pretreatment module 61 performs fine desulfurization on the flue gas that meets the emission standards of conventional pollutants, and cools the flue gas to 40-50°C to reach the optimal reaction temperature for CO2 chemical absorption. The flue gas inside the absorption module 62 and the CO2 absorbent react in reverse contact, wherein the flue gas enters from the bottom of the absorption module 62 and flows upward, and the CO2 absorbent is sprayed from the top of the absorption module 62 and flows downward. When the gas and liquid contact, the absorbent absorbs CO2 in the flue gas. The flue gas after pollution reduction and carbon reduction is transported to the chimney 7 through the exhaust port at the top of the absorption module 62, and finally discharged into the atmosphere. The absorbent rich in CO2 is transported from the absorbent exhaust port of the absorption module 62 to the desorption module 63, and the desorption of CO2 is completed under high temperature conditions. The desorbed absorbent returns to the absorption module 62 for cyclic reaction, and the desorbed high-purity CO2 is discharged for external treatment.

[0029] The steam pipe 8 transports the steam generated by the waste heat boiler 2 to the desorption module 63 as a heat source, so that the desorption module 63 reaches an optimal desorption temperature of 100-110° C. without using other steam in the plant area.

[0030] 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. A comprehensive industrial silicon flue gas treatment system for reducing pollution and carbon emissions, characterized by: The invention comprises a flue (1), a waste heat boiler (2), an SDS dry desulfurization device (3), a bag dust removal device (4), an SCR denitrification device (5), a carbon capture device (6) and a chimney (7) which are connected in sequence. The waste heat boiler (2) is connected to the carbon capture device (6) through a steam pipe (8) to supply steam thereto.

2. The comprehensive treatment system for industrial silicon flue gas with pollution reduction and carbon reduction as claimed in claim 1 is characterized by: The SDS dry desulfurization device (3) comprises a material storage and grinding module (31), a material unloading module (32), a material injection module (33) and a dry reaction module (34) which are connected in sequence. The desulfurization agent in the material storage and grinding module (31) enters the material injection module (33) through the material unloading module (32), is then sprayed out from the material injection module (33) to contact with the flue gas, and then enters the dry reaction module (34) with the flue gas to fully mix and react, thereby completing the removal of SO2.

3. The comprehensive treatment system for industrial silicon flue gas with pollution reduction and carbon reduction as claimed in claim 1 is characterized by: The bag dust removal device (4) comprises a dust collector body (41) and a dust removal fine screening module (42) arranged at the bottom of the dust collector body (41).

4. The comprehensive treatment system for industrial silicon flue gas with pollution reduction and carbon reduction as claimed in claim 1 is characterized by: The carbon capture device (6) comprises a pretreatment module (61), an absorption module (62) and a desorption module (63) which are connected in sequence, the top smoke exhaust port of the absorption module (62) is connected to the chimney (7), and the steam inlet of the desorption module (63) is connected to the steam outlet of the waste heat boiler (2) through a steam pipe (8).

5. The comprehensive treatment system for industrial silicon flue gas with pollution reduction and carbon reduction as claimed in claim 1 is characterized by: The SCR denitration device (5) is provided with a catalyst reserve layer and a catalyst operation layer.

6. The comprehensive treatment system for industrial silicon flue gas with pollution reduction and carbon reduction as claimed in claim 2 is characterized by: A venturi section is provided at the inlet area below the dry process reaction module (34), and the diameter of the venturi section is 55%-85% of the diameter of the reaction area above the dry process reaction module (34).

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