Circulating fluidized bed boiler low-load operation desulfurization device
By introducing a low-temperature desulfurization device into a circulating fluidized bed boiler during low-load operation, and using highly active desulfurizing agent powder mixed with flue gas, the problem of exceeding environmental standards during low-load operation is solved, achieving low-cost and efficient sulfur dioxide removal. It is suitable for boiler start-up and emergency failure, and extends equipment life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BAODING BAIGOU JIZHONG THERMAL POWER CO LTD
- Filing Date
- 2025-05-16
- Publication Date
- 2026-05-15
AI Technical Summary
When existing circulating fluidized bed boilers operate at low loads, the limestone dry desulfurization process is inefficient, resulting in excessive sulfur dioxide emissions in the flue gas. Furthermore, the limestone gypsum wet desulfurization process requires significant upfront investment and consumes a large amount of electricity, making it difficult to meet environmental protection requirements.
A desulfurization device for low-load operation of a circulating fluidized bed boiler is adopted, including a desulfurization feeding component and a low-temperature desulfurization reactor. High-activity desulfurizing agent powder is mixed with flue gas through a spray gun to achieve low-temperature desulfurization. Combined with the original in-furnace calcium injection desulfurization method, the sulfur dioxide emission concentration is ensured to be ≤30mg/m³.
It effectively solves the problem of exceeding environmental standards during low-load operation, reduces equipment investment costs, extends equipment life, reduces acid gas corrosion, is suitable for furnace start-up and emergency fault response, and achieves sulfur dioxide emission standards.
Smart Images
Figure CN224236491U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of flue gas treatment technology for circulating fluidized bed boilers, and in particular to a desulfurization device for low-load operation of circulating fluidized bed boilers. Background Technology
[0002] Currently, the mainstream desulfurization processes for circulating fluidized bed boilers are: in-furnace limestone dry desulfurization and limestone-gypsum wet desulfurization. For example... Figure 1 The diagram shows the flow chart for flue gas desulfurization in a conventional circulating fluidized bed boiler. The dry limestone desulfurization process involves desulfurization within the furnace, with an optimal reaction temperature of 800-950℃. Its desulfurization efficiency is significantly affected by the boiler bed temperature. However, in actual operation of circulating fluidized bed boilers, when the operating temperature is below 30MW, the boiler bed temperature is ≤600℃. Under these conditions, the desulfurization efficiency is extremely low, failing to guarantee that the flue gas meets emission standards and easily causing air pollution. While the wet limestone-gypsum desulfurization process is less affected by boiler operating conditions, it requires the construction of a desulfurization reaction tower and various supporting facilities, resulting in a huge initial investment. Furthermore, this process uses a large amount of electrical equipment, leading to high overall power consumption, and it easily generates desulfurization wastewater, solid waste, and other byproducts, which also contradicts the national energy conservation and emission reduction principles. Summary of the Invention
[0003] The purpose of this invention is to provide a desulfurization device for low-load operation of circulating fluidized bed boilers, which solves the problem of excessive sulfur dioxide emissions during the start-up process of circulating fluidized bed boilers and during low-load operation of circulating fluidized bed boilers due to production needs.
[0004] To achieve the above objectives, this utility model provides a desulfurization device for low-load operation of a circulating fluidized bed boiler, including a desulfurization feeding assembly. At the bottom of the desulfurization feeding assembly is a feeder, and below the feeder is a horizontally arranged discharge conveying pipe. A Roots blower is connected to the left side of the discharge conveying pipe, and an air preheater flue and a desulfurization reactor are connected to the right side of the discharge conveying pipe. A spray gun is installed between the air preheater flue and the desulfurization reactor and the discharge conveying pipe. An air preheater is installed between the air preheater flue and the desulfurization reactor. The air preheater flue, the air preheater, and the desulfurization reactor are connected via a flue gas duct.
[0005] Preferably, the desulfurization feeding assembly includes a desulfurization feeding port, which is connected to a negative pressure vacuum pump. The negative pressure vacuum pump is connected to the top of the desulfurizing agent silo through a feeding pipeline. A gate valve is provided below the desulfurizing agent silo, a buffer chamber is provided below the gate valve, and the feeder is provided below the buffer chamber.
[0006] Preferably, the desulfurizing agent silo, gate valve, buffer silo, and feeder are arranged in a straight line in the vertical direction.
[0007] Preferably, an air preheater flue gas inlet is provided above the air preheater flue, and an air preheater flue gas exhaust port is provided below the air preheater flue; the air preheater flue gas exhaust port is connected to the air preheater; the air preheater is connected to a desulfurization reactor inlet provided below the desulfurization reactor, and a desulfurization reactor exhaust port is provided above the desulfurization reactor.
[0008] Preferably, at least one set of quick-connect spray guns is symmetrically arranged on both sides of the air preheater flue and both sides of the desulfurization reactor. The quick-connect spray guns are divided into common quick-connects and spare quick-connects.
[0009] Preferably, the negative pressure vacuum pump is equipped with a vacuum pump pressure gauge, and the Roots blower is equipped with a blower pressure gauge.
[0010] Therefore, the desulfurization device for low-load operation of a circulating fluidized bed boiler described above has the following beneficial effects:
[0011] 1) Reusing the existing flue reduces initial equipment investment costs.
[0012] 2) It can solve the problem of excessive environmental protection standards caused by the low efficiency of the limestone dry desulfurization reaction in the boiler during start-up and low-load operation. Using this desulfurization device can ensure that the sulfur dioxide emission concentration is ≤30mg / m³.
[0013] 3) In addition to removing sulfur dioxide from flue gas, it can also remove acidic gases such as hydrogen chloride and hydrogen fluoride from flue gas, which helps to extend the service life of equipment, reduce equipment corrosion, and reduce air pollutants.
[0014] 4) It does not conflict with the original in-furnace desulfurization, does not require the removal of the original desulfurization device, and is additionally applicable to emergency backup in case of in-furnace desulfurization device failure and cases where secondary desulfurization of flue gas is required.
[0015] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0016] Figure 1 This is a flowchart of a conventional circulating fluidized bed boiler flue gas desulfurization process according to an embodiment of a desulfurization device for low-load operation of a circulating fluidized bed boiler.
[0017] Figure 2 This is a flow chart of flue gas desulfurization after adding a low-temperature desulfurization device in an embodiment of a circulating fluidized bed boiler desulfurization device under low load operation.
[0018] Figure 3 This is a schematic diagram of the structural composition of an embodiment of a desulfurization device for low-load operation of a circulating fluidized bed boiler according to this utility model;
[0019] Figure 4 This is an enlarged view of section A of an embodiment of a desulfurization device for low-load operation of a circulating fluidized bed boiler according to this utility model.
[0020] Figure Labels
[0021] 1. Desulfurization feed inlet; 2. Negative pressure vacuum pump; 3. Feed conveying pipeline; 4. Desulfurizing agent silo; 5. Gate valve; 6. Buffer silo; 7. Feeder; 8. Roots blower; 9. Discharge conveying pipeline; 10. Air preheater flue; 11. Desulfurization reactor; 12. Air preheater; 13. Spray gun; 14. Common quick-connect couplings; 15. Spare quick-connect couplings; 16. Flue gas duct; 17. Air preheater flue inlet; 18. Air preheater flue exhaust outlet; 19. Desulfurization reactor inlet; 20. Desulfurization reactor exhaust outlet; 21. Vacuum pump pressure gauge; 22. Blower pressure gauge. Detailed Implementation
[0022] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.
[0023] Unless otherwise defined, the technical or scientific terms used in this utility model shall have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar terms used in this utility model do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0024] Example 1
[0025] This utility model provides a desulfurization device for low-load operation of a circulating fluidized bed boiler, such as... Figure 3 As shown, the enlarged view of the structure at point A is as follows: Figure 4 As shown, the installation location in the existing equipment is as follows: Figure 2As shown. The entire device includes a desulfurization feeding assembly, which includes a desulfurization feeding port 1, located on the ground for easy feeding. The desulfurization feeding port 1 is connected to a negative pressure vacuum pump 2, which provides power for the desulfurizing agent delivery. The negative pressure vacuum pump 2 is connected to the top of the desulfurizing agent silo 4 via a feed pipeline 3. A gate valve 5 is located below the desulfurizing agent silo 4, a buffer chamber 6 is located below the gate valve 5, and a feeder 7 is located below the buffer chamber 6. The desulfurizing agent silo 4, gate valve 5, buffer chamber 6, and feeder 7 are arranged in a straight line in the vertical direction. This straight arrangement allows the desulfurizing agent to fall under gravity, eliminating the need for additional power equipment.
[0026] At the bottom of the desulfurization feeding assembly is the feeder 7. Below the feeder 7, a discharge conveying pipe 9 is arranged horizontally. A Roots blower 8 is connected to the left side of the discharge conveying pipe 9. An air preheater flue 10 and a desulfurization reactor 11 are connected to the right side of the discharge conveying pipe 9. A spray gun 13 is installed between the air preheater flue 10 and the desulfurization reactor 11 and the discharge conveying pipe 9. An air preheater 12 is installed between the air preheater flue 10 and the desulfurization reactor 11. The air preheater flue 10, the air preheater 12, and the desulfurization reactor 11 are connected by a flue gas duct 16. A mixing grid is installed inside the desulfurization reactor 11.
[0027] An air preheater flue gas inlet 17 is provided above the air preheater flue gas duct 10, and an air preheater flue gas exhaust port 18 is provided below the air preheater flue gas duct 10; the air preheater flue gas exhaust port 18 is connected to the air preheater 12; the air preheater 12 is connected to the desulfurization reactor inlet 19 provided below the desulfurization reactor 11, and the desulfurization reactor exhaust port 20 is provided above the desulfurization reactor 11.
[0028] At least one set of quick-connect spray guns is symmetrically arranged on both sides of the air preheater flue 10 and both sides of the desulfurization reactor 11. These quick-connect spray guns are divided into standard quick-connect spray guns 14 and spare quick-connect spray guns 15. In this embodiment, both the air preheater flue 10 and the desulfurization reactor 11 are equipped with two sets of standard quick-connect spray guns 14 and two sets of spare quick-connect spray guns 15. A total of four sets of spray guns 13 are provided in the air preheater flue 10 and the desulfurization reactor 11, i.e., eight spray guns 13. The spray guns 13 are distributed at a 180-degree spray angle to the flue gas direction, ensuring that the desulfurizing agent can be fully mixed with the flue gas and that a sufficient reaction zone is maintained.
[0029] The number of spray guns 13 can be adjusted according to the amount of flue gas. The standard quick connector 14 and the spare quick connector 15 are completely identical. The spare quick connector 15 serves as technical redundancy and can be quickly put into operation when additional spray guns 13 are needed or when the standard quick connector 14 fails.
[0030] The negative pressure vacuum pump 2 is equipped with a vacuum pump pressure gauge 21, and the Roots blower 8 is equipped with a blower pressure gauge 22. The vacuum pump pressure gauge 21 and the blower pressure gauge 22 are used to monitor the corresponding equipment operating pressure to avoid equipment failure due to excessive pressure or substandard flue gas treatment due to insufficient pressure.
[0031] The specific difference between the operation mode of the desulfurization device for low-load operation of a circulating fluidized bed boiler described in this embodiment and the original process is as follows: Figure 1 As shown, conventional circulating fluidized bed boiler flue gas desulfurization uses in-furnace calcium injection, where limestone powder is directly injected into the boiler. At a temperature of 800-950℃, the limestone decomposes into calcium oxide, which then reacts with sulfur dioxide in the flue gas to form calcium sulfate. The drawback of this desulfurization process is its significant dependence on boiler furnace temperature. During boiler start-up or low-load operation, the furnace temperature is low, leading to low desulfurization efficiency and a risk of exceeding desulfurization limits.
[0032] like Figure 2 As shown, after adding a desulfurization device for low-load operation of the circulating fluidized bed boiler, the original in-furnace calcium injection desulfurization method is retained. However, when the boiler is started up or operating at low load, the in-furnace calcium injection method is too inefficient. Excessive sulfur dioxide flue gas enters the low-temperature desulfurization reactor after passing through the return feeder, superheater, economizer, and air preheater. Highly active desulfurizing agent powder is injected through spray guns into the air preheater flue and the low-temperature desulfurization reactor, mixing thoroughly with the flue gas. The flue gas (≥50℃) reacts with highly active sodium bicarbonate to remove sulfur dioxide. The compliant flue gas is then filtered by a bag filter and discharged into the atmosphere through the chimney. Combined with... Figure 3 and Figure 4 The desulfurizing agent is drawn in by the negative pressure vacuum pump 2 and temporarily stored in the desulfurizing agent silo 4. It then enters the buffer silo 6 through the gate valve 5 and falls into the discharge conveying pipe 9 by the feeder 7. It is then blown into the air preheater flue 10 and the desulfurization reactor 11 by the Roots blower 8, where it is heated and sprayed by the spray gun 13 to react with the flue gas in a desulfurization process. During this process, the amount of desulfurizing agent added can be adjusted by regulating the working frequency of the feeder 7. The buffer silo 6 can alleviate the clogging of desulfurizing agent powder and reduce the equipment failure rate. The gate valve 5 is used for emergency equipment repair and can be used to cut off the connection between the desulfurizing agent silo 4 and the equipment below.
[0033] Therefore, this utility model adopts the above-mentioned desulfurization device for low-load operation of circulating fluidized bed boiler, which makes use of the original flue and does not require the removal of the original desulfurization device. It solves the problem of excessive environmental protection standards caused by the low efficiency of limestone dry desulfurization reaction in the furnace during boiler start-up and low-load operation. It can also remove acidic gases such as hydrogen chloride and hydrogen fluoride from the flue gas, which helps to extend the service life of the equipment, reduce equipment corrosion, and reduce air pollutants.
[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solution of this utility model, and these modifications or equivalent substitutions cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of this utility model.
Claims
1. A desulfurization device for low-load operation of a circulating fluidized bed boiler, characterized in that: The system includes a desulfurization feeding assembly, with a feeder at the bottom. A discharge conveying pipe is horizontally arranged below the feeder. A Roots blower is connected to the left side of the discharge conveying pipe, and an air preheater flue and a desulfurization reactor are connected to the right side of the discharge conveying pipe. A spray gun is installed between the air preheater flue and the desulfurization reactor and the discharge conveying pipe. An air preheater is installed between the air preheater flue and the desulfurization reactor. The air preheater flue, the air preheater, and the desulfurization reactor are connected by a flue gas duct.
2. The desulfurization device for low-load operation of a circulating fluidized bed boiler according to claim 1, characterized in that: The desulfurization feeding assembly includes a desulfurization feeding port, which is connected to a negative pressure vacuum pump. The negative pressure vacuum pump is connected to the top of the desulfurizing agent silo through a feeding pipeline. A gate valve is installed below the desulfurizing agent silo, a buffer chamber is installed below the gate valve, and the feeder is installed below the buffer chamber.
3. A desulfurization device for low-load operation of a circulating fluidized bed boiler according to claim 2, characterized in that: The desulfurizing agent silo, gate valve, buffer silo, and feeder are arranged in a straight line in the vertical direction.
4. The desulfurization device for low-load operation of a circulating fluidized bed boiler according to claim 1, characterized in that: An air preheater flue gas inlet is provided above the air preheater flue gas duct, and an air preheater flue gas exhaust port is provided below the air preheater flue gas duct; the air preheater flue gas exhaust port is connected to the air preheater; the air preheater is connected to a desulfurization reactor inlet provided below the desulfurization reactor, and a desulfurization reactor exhaust port is provided above the desulfurization reactor.
5. A desulfurization device for low-load operation of a circulating fluidized bed boiler according to claim 1, characterized in that: At least one set of quick-connect spray guns is symmetrically arranged on both sides of the air preheater flue and both sides of the desulfurization reactor. The quick-connect spray guns are divided into common quick-connects and spare quick-connects.
6. A desulfurization device for low-load operation of a circulating fluidized bed boiler according to claim 2, characterized in that: The negative pressure vacuum pump is equipped with a vacuum pump pressure gauge, and the Roots blower is equipped with a blower pressure gauge.