Double purification and removal device for SO3 in boiler flue gas
By installing a sodium sulfite solution and powder addition device on the boiler flue, SO3 is removed by gas-solid reaction, which solves the negative impact of SO3 on the air preheater and SCR denitrification reactor, and achieves efficient purification and low-cost SO3 removal.
Patent Information
- Application Number
- CN202422866240.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2034-11-25
AI Technical Summary
Existing technologies cannot effectively mitigate or eliminate the negative impact of SO3 on air preheaters and SCR denitrification reactors, and increase the investment and operating costs of power plants.
A sodium sulfite solution addition device is installed in the flue after the boiler economizer, and a sodium sulfite powder addition device is installed in the flue after the electrostatic precipitator. The two devices are operated in coordination through an interlocking control device. The sodium sulfite solution and powder react with SO3 in a gas-solid reaction to form sodium sulfate solid particles that can settle or be captured, thereby removing SO3.
It achieves efficient SO3 purification, solves the problems of air preheater blockage and corrosion, eliminates environmental hazards, and reduces investment and operation and maintenance costs.
Smart Images
Figure CN223602303U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a boiler flue gas SO3 double purification removal device, and more particularly to a boiler flue gas SO3 double purification removal device composed of a sodium sulfite solution adding device and a sodium sulfite powder adding device, wherein the sodium sulfite solution adding device is composed of a sodium sulfite solution storage tank, a conveying pipeline, a booster pump and an atomizing spray gun, the sodium sulfite powder adding device is composed of a sodium sulfite powder bin, a star feeder, a compressed air tank, a compressed air pipeline and a powder spray gun, and an interlocking control device is arranged between the sodium sulfite solution adding device and the sodium sulfite powder adding device. BACKGROUND
[0002] During the coal combustion process, a certain concentration of SO3 is generated, and after being discharged into the atmosphere, SO3 will further form haze together with other atmospheric pollutants, thereby causing harm to the environment and human health. During the operation of power plant equipment, SO3 can also cause serious problems such as air preheater blockage, equipment corrosion and reduction of the efficiency of the SCR denitration reactor, thereby affecting the normal operation of the power plant equipment.
[0003] Although the wet flue gas desulfurization device is widely installed in power plants in China, its SO3 removal is very limited. Some domestic power plants have added a wet-type electric dust removal device after the wet desulfurization tower for the purpose of aerosol control. Although the effect of the wet-type electric dust removal device in removing SO3 is still obvious, it cannot alleviate or eliminate the serious negative impact of SO3 on the air preheater and the SCR denitration reactor because it is arranged at the end of the tail gas purification process, and it also greatly increases the investment and operating costs of the power plant. Therefore, the innovation and development of the boiler flue gas SO3 purification removal process are still very important.
[0004] Although the wet flue gas desulfurization device is widely installed in power plants in China, its SO3 removal is very limited. Some domestic power plants have added a wet-type electric dust removal device after the wet desulfurization tower for the purpose of aerosol control. Although the effect of the wet-type electric dust removal device in removing SO3 is still obvious, it cannot alleviate or eliminate the serious negative impact of SO3 on the air preheater and the SCR denitration reactor because it is arranged at the end of the tail gas purification process, and it also greatly increases the investment and operating costs of the power plant. Therefore, the innovation and development of the boiler flue gas SO3 purification removal process are still very important.
[0005] The present application designs a boiler flue gas SO3 double purification removal device which is arranged on the flue after the boiler economizer, before the SCR denitration reactor and the air preheater, and the sodium sulfite solution adding device is arranged on the flue after the electrostatic precipitator, and an interlocking control device is arranged between the sodium sulfite solution adding device and the sodium sulfite powder adding device.
[0006] The patent technology not only solves the problems of SO3 blocking and corrosion of the air preheater, but also solves the problems of purifying and removing SO3 which "escapes" from the front end of the electrostatic precipitator and newly formed SO3 in the flue gas of the electrostatic precipitator, and completely eliminates the environmental hazards caused by discharging SO3 into the environment.
[0007] The patent technology has high efficiency of double purification and removal of SO3, strong process synergy, advanced and reliable process, reasonable investment cost, low operation and maintenance cost, and is suitable for purifying and removing SO3 of the coal-fired boiler. Content of the utility model
[0008] The patent designs a boiler flue gas SO3 double purification and removal device which is provided with a sodium sulfite solution adding device on the flue gas duct after the coal-saving device of the coal-fired boiler and before the SCR denitration reactor and the air preheater, and provided with a sodium sulfite powder adding device on the flue gas duct after the electrostatic precipitator, and provided with an interlocking control device between the sodium sulfite solution adding device and the sodium sulfite powder adding device.
[0009] The patent is provided with a sodium sulfite solution adding device on the flue gas duct after the coal-saving device of the coal-fired boiler and before the SCR denitration reactor and the air preheater. The sodium sulfite solution adding device is composed of a NaSO3 solution storage tank, a conveying pipeline, a booster pump and an atomizing spray gun.
[0010] The patent is provided with a sodium sulfite powder adding device on the flue gas duct after the electrostatic precipitator. The sodium sulfite powder adding device is mainly composed of a NaSO3 powder bin, a star feeder, a compressed air tank, a compressed air pipeline and a powder spray gun.
[0011] After the patent is put into operation, the boiler burns to produce flue gas, the sodium sulfite solution in the sodium sulfite solution storage tank of the sodium sulfite solution adding device enters the conveying pipeline, and under the action of the booster pump, the sodium sulfite solution is sprayed into the flue gas duct after the coal-saving device of the boiler and before the SCR denitration reactor and the air preheater through the atomizing spray gun. The water in the solution evaporates quickly at high temperature to form sodium sulfite particles with a particle size of less than 20 microns. SO3 gas in the flue gas reacts with the sodium sulfite particles as follows:
[0012] Na2SO3+SO3=Na2SO4+SO2
[0013] The final product of the reaction is a sodium sulfate solid particle which is naturally settled in the subsequent flue gas or captured by the subsequent electrostatic precipitator. The SO2 in the final product of the reaction is removed by the subsequent purification unit.
[0014] After the patent is put into operation, the sodium sulfite particles in the sodium sulfite bin of the sodium sulfite powder adding device enter the compressed air pipeline connected with the compressed air tank under the action of the star feeder, and are sprayed into the flue gas duct after the electrostatic precipitator through the powder spray gun.
[0015] SO3 gas in flue gas and injected sodium sulfite particles have the following gas-solid reaction:
[0016] Na2SO3 + SO3 = Na2SO4 + SO2
[0017] Sodium sulfate solid particles in the final reaction product will be naturally settled in the subsequent flue or captured by the subsequent purification unit, and SO2 in the final reaction product will be removed by the subsequent purification unit.
[0018] When the sulfur content in the boiler fuel coal is less than 0.5%, the interlock control device automatically closes the sodium sulfite solution adding device, and the sodium sulfite powder adding device remains running. When the sulfur content in the boiler fuel coal is in the range of 0.5%-1%, the interlock control device automatically closes the sodium sulfite powder adding device, and the sodium sulfite solution adding device remains running. When the sulfur content in the boiler fuel coal is higher than 1%, both the sodium sulfite solution adding device and the sodium sulfite powder adding device are put into operation.
[0019] The concentration of sodium sulfite solution used in the patent is 5-10%, and the particle size of compressed sodium sulfate particles is 10-20 μm.
[0020] The patent has been verified by pilot test and demonstration project, and the effect is good.
[0021] The patent technology has high efficiency of double purification and removal of SO3, strong process synergy, advanced and reliable process, reasonable investment cost, low operation and maintenance cost, and is suitable for purification and removal of SO3 in coal-fired boiler. BRIEF DESCRIPTION OF DRAWINGS
[0022] The application will be further described in detail below with reference to the accompanying drawings.
[0023] Figure 1 is a process flow diagram of the patent.
[0024] In the figure: 1. boiler, 2. economizer, 3. SCR denitration reactor, 4. air preheater, 5. electrostatic precipitator, 6. sodium sulfite solution storage tank, 7. conveying pipeline, 8. booster pump, 9. atomizing lance, 10. sodium sulfite powder bin, 11. star feeder, 12. compressed air tank, 13. compressed air pipeline, 14. powder lance, 15. sodium sulfite solution adding device, 16. sodium sulfite powder adding device, 17. interlock control device. DETAILED DESCRIPTION
[0025] After the boiler flue gas SO3 double purification removal device of the patent is put into operation, the boiler (1) burns to produce flue gas, the sodium sulfite solution is added to the sodium sulfite solution storage tank (6) in the sodium sulfite solution adding device (15), the sodium sulfite solution in the sodium sulfite solution storage tank (6) enters the conveying pipeline (7), under the action of the booster pump (8), the sodium sulfite solution is sprayed into the flue duct after the economizer (2) of the boiler (1) and before the SCR denitration reactor (3) and the air preheater (4) through the atomizing spray gun (9), the water in the solution is rapidly evaporated at high temperature, forming sodium sulfite particles with a particle size of less than 20 μm, and the SO3 gas in the flue gas reacts with the sodium sulfite particles as follows:
[0026] Na2SO3+SO3=Na2SO4+SO2
[0027] The sodium sulfate solid particles in the final reaction product will naturally settle in the subsequent flue or be captured by the subsequent electrostatic precipitator (5), and the SO2 in the final reaction product will be removed by the subsequent purification unit.
[0028] After the boiler flue gas SO3 double purification removal device of the patent is put into operation, the sodium sulfite powder adding device (16) is added to the sodium sulfite bin (10), the sodium sulfite particles in the sodium sulfite bin (10) are introduced into the compressed air pipeline (13) connected with the compressed air tank (12) under the action of the star feeder (11), and the sodium sulfite particles are sprayed into the flue after the electrostatic precipitator (5) through the powder spray gun (14).
[0029] The SO3 gas in the flue gas reacts with the sprayed sodium sulfite particles as follows:
[0030] Na2SO3+SO3=Na2SO4+SO2
[0031] The sodium sulfate solid particles in the final reaction product will naturally settle in the subsequent flue or be captured by the subsequent purification unit, and the SO2 in the final reaction product will be removed by the subsequent purification unit.
[0032] After the boiler flue gas SO3 double purification removal device of the patent is put into operation, when the sulfur content in the boiler fuel coal is less than 0.5%, the interlocking control device automatically closes the sodium sulfite solution adding device, and the sodium sulfite powder adding device remains running. When the sulfur content in the boiler fuel coal is in the range of 0.5%-1%, the interlocking control device automatically closes the sodium sulfite powder adding device, and the sodium sulfite solution adding device remains running, and when the sulfur content in the boiler fuel coal is higher than 1%, both the sodium sulfite solution adding device and the sodium sulfite powder adding device are put into operation.
[0033] The concentration of the sodium sulfite solution used in the patent is 5-10%, and the particle size of the sodium sulfite particles is 10-20 μm.
[0034] The patent has been verified by a pilot and demonstration project, and the effect is good.
[0035] The above is only a specific embodiment of the present application, and the technical features of the present application are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present application should be included in the patent scope of the present application.
Claims
1. A boiler flue gas SO3 dual purification removal device, which is composed of a sodium sulfite solution adding device and a sodium sulfite powder adding device, characterized in that: The sodium sulfite solution adding device is arranged on the flue after the boiler economizer, the SCR denitration reactor and the air preheater, and the sodium sulfite powder adding device is arranged on the flue after the electrostatic precipitator, and the interlocking control device is arranged between the sodium sulfite solution adding device and the sodium sulfite powder adding device.
2. The device for removing SO3 in boiler flue gas according to claim 1, characterized in that: The sodium sulfite solution adding device is composed of a NaSO3 solution storage tank, a conveying pipeline, a booster pump and an atomizing lance.
3. The device for removing SO3 in boiler flue gas according to claim 1, characterized in that: The sodium sulfite powder adding device is composed of a NaSO3 powder bin, a star feeder, a compressed air tank, a compressed air pipeline and a powder lance.
4. The device for removing SO3 in boiler flue gas according to claim 1, characterized in that: The interlocking control device is connected with the sodium sulfite solution adding device and the sodium sulfite powder adding device respectively.
5. The device for removing SO3 in boiler flue gas according to claim 1, characterized in that: The sodium sulfite particle size is 10-20 μm.