Double purification and removal method for SO3 in boiler flue gas
By setting up a sodium sulfite solution and powder addition device in the boiler flue gas, and using gas-solid reaction and interlocking control devices, the problem of poor SO3 removal effect is solved, efficient and low-cost flue gas purification is achieved, and the environment is protected and equipment.
Patent Information
- Application Number
- CN202411688092.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-01-10
AI Technical Summary
The current technology has limited removal effect of SO3 in boiler flue gas, resulting in air preloader blockage, equipment corrosion and SCR denitrification reactor efficiency, which increases the investment and operating costs of power plants, and cannot effectively slow down or eliminate environmental hazards. .
Set up a sodium sulfite solution and powder addition device in the boiler flue gas, convert SO3 into sedimentable sodium sulfate particles through gas-solid reaction, and use the interlocking control device to automatically adjust the operation of the removal device according to the sulfur content of the fuel coal to ensure that Efficient purification.
The dual purification and removal of SO3 has been achieved, completely eliminating the harm of SO3 to the air preloader and the environment, improving the purification efficiency, reducing operation and maintenance costs, and is suitable for the application of coal-fired boilers.
Smart Images
Figure CN119281088A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a boiler flue gas SO 3 The double purification removal method particularly relates to a method comprising a sodium sulfite solution adding device and a sodium sulfite powder adding device, wherein the sodium sulfite solution adding device comprises a sodium sulfite solution storage tank, a conveying pipeline, a booster pump and an atomizing spray gun, and the sodium sulfite powder adding device comprises a sodium sulfite powder silo, 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. 3 Double purification and removal method.
[0002] During coal combustion, a certain concentration of SO is produced. 3 , SO 3 After being discharged into the atmosphere, it will further form haze together with other air pollutants, thus causing harm to the environment, ecology and human health. 3 It will also cause serious problems such as air preheater blockage, equipment corrosion, and reduced efficiency of the SCR denitrification reactor, affecting the normal operation of power plant equipment.
[0003] Currently, Western developed countries have a strong interest in SO 3 Strict emission limits have been set for SO2 emissions from power plants. 3 The United States has put forward requirements for emissions and called for strengthening the research on synergistic removal processes, but has not yet put forward mandatory requirements.
[0004] my country's power plants are generally equipped with wet flue gas desulfurization equipment, but its effect on SO 3 The removal of SO is very limited. Some power plants in China have added wet electrostatic precipitators after the wet desulfurization tower for the purpose of aerosol control. 3 The effect is still very obvious, but because it is set at the end of the tail gas purification process, it cannot slow down or eliminate SO 3 It has a serious negative impact on the air preheater and SCR denitrification reactor, and also greatly increases the investment and operating costs of the power plant. 3 Innovation and development of purification and removal processes remain very important.
[0005] my country's power plants are generally equipped with wet flue gas desulfurization equipment, but its effect on SO 3 The removal of SO is very limited. Some power plants in China have added wet electrostatic precipitators after the wet desulfurization tower for the purpose of aerosol control. 3 The effect is still very obvious, but because it is set at the end of the tail gas purification process, it cannot slow down or eliminate SO 3It has a serious negative impact on the air preheater and SCR denitrification reactor, and also greatly increases the investment and operating costs of the power plant. 3 Innovation and development of purification and removal processes remain very important.
[0006] This patent designs a boiler flue gas SO2 with a sodium sulfite solution adding device installed on the flue after the boiler economizer and before the SCR denitrification reactor and the air preheater, and a sodium sulfite powder adding device installed on the flue after the electrostatic precipitator. 3 An interlocking control device is arranged between the double purification and removal device, the sodium sulfite solution adding device and the sodium sulfite powder adding device.
[0007] This patented technology not only solves SO 3 It solves the blockage and corrosion problems of the air preheater and solves the SO2 “escaped” from the purification process at the front end of the electrostatic precipitator. 3 and newly formed SO in the flue gas in the electrostatic precipitator 3 The purification and removal problem completely eliminates SO 3 Environmental damage caused by discharge into the environment.
[0008] This patented technology is for SO 3 The double purification removal efficiency is high, the process synergy is strong, the process is advanced and reliable, the investment cost is reasonable, and the operation and maintenance cost is low. It is suitable for coal-fired boiler SO 3 purification and removal.
[0009] This patent designs a boiler flue gas SO2 with a sodium sulfite solution adding device installed on the flue after the economizer of a coal-fired boiler and before the SCR denitrification reactor and the air preheater, and a sodium sulfite powder adding device installed on the flue after the electrostatic precipitator. 3 The double purification and removal method is to set an interlocking control device between the sodium sulfite solution adding device and the sodium sulfite powder adding device.
[0010] This patent sets a sodium sulfite solution adding device on the flue after the economizer of the coal-fired boiler and before the SCR denitrification reactor and the air preheater. The sodium sulfite solution adding device consists of NaSO 3 It consists of a solution storage tank, a delivery pipeline, a booster pump and an atomizing spray gun.
[0011] This patent sets a sodium sulfite powder adding device on the flue after the electrostatic precipitator. The sodium sulfite powder adding device mainly contains NaSO 3 It consists of a powder silo, a star feeder, a compressed air tank, a compressed air pipeline and a powder spray gun.
[0012] After the patent is put into operation, the boiler burns to generate flue gas, and the sodium sulfite solution is added to the sodium sulfite solution in the sodium sulfite solution storage tank of the device and enters the delivery pipeline. Under the action of the booster pump, the sodium sulfite solution is sprayed into the flue after the boiler economizer and before the SCR denitrification reactor and the air preheater through the atomizing spray gun. The water in the solution evaporates rapidly at high temperature to form sodium sulfite particles with a particle size of less than 20μm, and SO in the flue gas 3 The gas and sodium sulfite particles undergo the following gas-solid reaction: Na 2 SO 3 +SO 3 =Na 2 SO 4 +SO 2 The solid particles of sodium sulfate in the final product of the reaction will settle naturally in the subsequent flue or be captured by the subsequent electrostatic precipitator. 2 Removed by subsequent purification units.
[0013] After this patent is put into operation, the sodium sulfite particles in the sodium sulfite silo in the sodium sulfite powder adding device enter the compressed air pipeline connected to the compressed air tank under the action of the star feeder, and are sprayed into the flue after the electrostatic precipitator through the powder spray gun.
[0014] SO in flue gas 3 The gas and the injected sodium sulfite particles undergo the following gas-solid reaction: Na 2 SO 3 +SO 3 =Na 2 SO 4 +SO 2 The solid particles of sodium sulfate in the final product of the reaction will naturally settle in the subsequent flue or be captured by the subsequent purification unit. 2 Removed by subsequent purification units.
[0015] After this patent is put into operation, when the sulfur content in the boiler fuel coal is lower than 0.5%, the interlocking control device automatically shuts down the sodium sulfite solution adding device, and the sodium sulfite powder adding device keeps running. When the sulfur content in the boiler fuel coal is in the range of 0.5%-1%, the interlocking control device automatically shuts down the sodium sulfite powder adding device, and the sodium sulfite solution adding device keeps 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.
[0016] The concentration of the sodium sulfite solution used in this patent is 5-10%, and the particle size of the compressed sodium sulfite particles is 10-20μm.
[0017] This patent has been verified by pilot and demonstration projects, with good results.
[0018] This patented technology is for SO 3 The double purification removal efficiency is high, the process synergy is strong, the process is advanced and reliable, the investment cost is reasonable, and the operation and maintenance cost is low. It is suitable for coal-fired boiler SO 3 purification and removal.
[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings.
[0020] Figure 1 It is a schematic diagram of the process flow of this patent.
[0021] In the figure: 1. boiler, 2. economizer, 3. SCR denitrification reactor, 4. air preheater, 5. electrostatic precipitator, 6. sodium sulfite solution storage tank, 7. conveying pipeline, 8. booster pump, 9. atomizing spray gun, 10. sodium sulfite powder silo, 11. star feeder, 12. compressed air tank, 13. compressed air pipeline, 14. powder spray gun, 15. sodium sulfite solution adding device, 16. sodium sulfite powder adding device, 17. interlocking control device.
[0022] This patent is a boiler flue gas SO 3 After the double purification and removal method is put into operation, the boiler (1) burns to generate flue gas, and the sodium sulfite solution in the sodium sulfite solution storage tank (6) of the sodium sulfite solution adding device (15) enters the conveying pipeline (7). Under the action of the booster pump (8), the sodium sulfite solution is sprayed into the flue after the economizer (2) of the boiler (1) and before the SCR denitrification reactor (3) and the air preheater (4) through the atomizing spray gun (9). The water in the solution evaporates rapidly at high temperature to form sodium sulfite particles with a particle size of less than 20 μm, and SO in the flue gas is reduced. 3 The gas and sodium sulfite particles undergo the following gas-solid reaction: Na 2 SO 3 +SO 3 =Na 2 SO 4 +SO 2 The solid particles of sodium sulfate in the final product of the reaction will settle naturally in the subsequent flue or be captured by the subsequent electrostatic precipitator (5). 2 Removed by subsequent purification units.
[0023] This patent is a boiler flue gas SO 3After the double purification and removal method is put into operation, the sodium sulfite particles in the sodium sulfite silo (10) in the sodium sulfite powder adding device (16) enter the compressed air pipeline (13) connected to the compressed air tank (12) under the action of the star feeder (11), and are sprayed into the flue after the electrostatic precipitator (5) through the powder spray gun (14).
[0024] SO in flue gas 3 The gas and the injected sodium sulfite particles undergo the following gas-solid reaction: Na 2 SO 3 +SO 3 =Na 2 SO 4 +SO 2 The solid particles of sodium sulfate in the final product of the reaction will naturally settle in the subsequent flue or be captured by the subsequent purification unit. 2 Removed by subsequent purification units.
[0025] This patent is a boiler flue gas SO 3 After the double purification and removal method is put into operation, when the sulfur content in the boiler fuel coal is lower than 0.5%, the interlocking control device automatically shuts down the sodium sulfite solution adding device, and the sodium sulfite powder adding device keeps running. When the sulfur content in the boiler fuel coal is in the range of 0.5%-1%, the interlocking control device automatically shuts down the sodium sulfite powder adding device, and the sodium sulfite solution adding device keeps 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.
[0026] The concentration of the sodium sulfite solution used in this patent is 5-10%, and the particle size of the sodium sulfite particles is 10-20 μm.
[0027] This patent has been verified by pilot and demonstration projects, with good results.
[0028] The above is only a specific implementation of the present invention, and the technical features of the present invention are not limited thereto. Any changes or modifications made by technicians in the field of the present invention should be included in the patent scope of the present invention.
Claims
1. A method for double purification and removal of SO3 from boiler flue gas, comprising a sodium sulfite solution adding device and a sodium sulfite powder adding device, characterized in that: A sodium sulfite solution adding device is arranged on the flue after the boiler economizer and before the SCR denitrification reactor and the air preheater, a sodium sulfite powder 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.
2. A method for double purification and removal of SO3 from boiler flue gas according to claim 1, characterized in that: The sodium sulfite solution adding device consists of a NaSO3 solution storage tank, a delivery pipeline, a booster pump and an atomizing spray gun.
3. A method for double purification and removal of SO3 from boiler flue gas according to claim 1, characterized in that: The sodium sulfite powder adding device consists of a NaSO3 powder silo, a star feeder, a compressed air tank, a compressed air pipeline and a powder spray gun.
4. A method for double purification and removal of SO3 from 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 method for double purification and removal of SO3 from boiler flue gas according to claim 1, characterized in that: When the sulfur content in the boiler fuel coal is lower than 0.5%, the interlocking control device automatically shuts down the sodium sulfite solution adding device, and the sodium sulfite powder adding device keeps running. When the sulfur content in the boiler fuel coal is in the range of 0.5%-1%, the interlocking control device automatically shuts down the sodium sulfite powder adding device, and the sodium sulfite solution adding device keeps 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.
6. A method for double purification and removal of SO3 from boiler flue gas according to claim 1, characterized in that: The concentration of the sodium sulfite solution is 5-10%, and the particle size of the sodium sulfite particles is 10-20 μm.