A large coal-fired power plant combined desulfurization flue system

Abstract

The utility model discloses a large -scale coal -fired power station leads to increase and unifies one desulfurization flue system, including leading to the air component and desulfurization device through the flue intercommunication, and the air inlet of desulfurization device is connected with the air outlet of leading to the air component, and the air outlet of desulfurization device is connected with the chimney, and desulfurization device still has the desulfurization bypass in parallel, the air inlet and the air outlet of desulfurization device all are provided with first electric baffle, and the second electric baffle is provided on the desulfurization bypass, and first electric baffle and second electric baffle all are electrically connected with controller, to control first electric baffle and second electric baffle step -by -step start -up when switching the use state of desulfurization device. The utility model can reduce the factory investment and reduce the operation power consumption, and first electric baffle and second electric baffle step -by -step start -up when switching the use state of desulfurization device, reduce the pressure fluctuation of boiler furnace, avoid the trip accident of boiler.

Description

Technical Field

[0001] This utility model belongs to the field of thermal power generation technology, and in particular relates to a desulfurization flue system that integrates desulfurization and flue gas generation in a large coal-fired power plant. Background Technology

[0002] Currently, with the development of fan technology, large-scale coal-fired power plants both domestically and internationally have adopted the "integrated induced draft and booster fan" approach. This eliminates the need for desulfurization booster fans and combines the boiler's induced draft fan and the desulfurization unit's booster fan into a single, higher-head fan. The induced draft fan overcomes the resistance from the boiler to the desulfurization unit, the desulfurization system, and the chimney, saving on plant construction costs and reducing power plant operating power consumption. Furthermore, to improve unit stability and reliability as well as facilitate operation and maintenance, desulfurization bypass flues are often installed on the desulfurization equipment. This allows flue gas to bypass the desulfurization equipment in case of equipment failure, enabling maintenance and repair of the desulfurization unit without shutting down the plant. The desulfurization bypass flue can also be switched to operate when burning low-sulfur coal (where flue gas emissions meet environmental emission requirements without desulfurization equipment), further saving power plant power consumption. However, the applicant discovered that when using the "integrated induced draft and desulfurization" technology, the resistance of the entire flue gas system (including the desulfurization system) is overcome by the induced draft fan. When switching to or not using the desulfurization equipment, the resistance of the entire flue gas system changes significantly, which can easily cause the induced draft fan to overspeed or cause large fluctuations in the boiler furnace pressure, which can easily lead to boiler tripping accidents. Utility Model Content

[0003] The purpose of this utility model is to overcome the defects of the existing technology and provide a large-scale coal-fired power plant integrated desulfurization flue system. The induced draft fan and the desulfurization booster fan are combined and set up to reduce the investment in plant construction and reduce the power consumption during operation. At the same time, the operation status of the desulfurization device is switched by a first electric damper set at the air inlet and air outlet of the desulfurization device and a second electric damper set on the desulfurization bypass. The first electric damper and the second electric damper are started in stages when switching the operation status of the desulfurization device, which reduces the pressure fluctuation of the boiler furnace and avoids boiler shutdown accidents.

[0004] The objective of this utility model is achieved through the following technical solution: A large-scale coal-fired power plant integrated desulfurization flue system includes an induced draft fan assembly and a desulfurization device connected through a flue. The air inlet of the desulfurization device is connected to the air outlet of the induced draft fan assembly, and the air outlet of the desulfurization device is connected to a chimney. The desulfurization device is also connected in parallel with a desulfurization bypass. A first electric damper is installed at both the air inlet and the air outlet of the desulfurization device, and a second electric damper is installed on the desulfurization bypass. Both the first and second electric dampers are electrically connected to a controller so that the first and second electric dampers can be activated in stages when the desulfurization device switches between operating states.

[0005] In one embodiment, the desulfurization device is connected to the induced draft assembly and the chimney via a flue gas pipeline, and the first electric damper can completely seal the flue gas pipeline.

[0006] In one embodiment, the desulfurization bypass is connected to the induced draft assembly and the chimney via a bypass flue, and the second electric damper can completely seal the bypass flue.

[0007] In one embodiment, the second electric baffle is located between the two first electric baffles.

[0008] In one embodiment, the induced draft assembly includes two induced draft fans connected in parallel, and the two induced draft fans are also connected to a dust collector.

[0009] In one embodiment, the chimney is connected to two coal-fired power units, each of which includes the induced draft assembly and the desulfurization device.

[0010] In one embodiment, the two coal-fired units are symmetrically arranged on both sides of the chimney.

[0011] In one embodiment, when the desulfurization device switches between operating states, it first activates the first or second electric damper that is in a closed state, and then delays the activation of the other electric damper.

[0012] The beneficial effects of this utility model are as follows: The induced draft fan and desulfurization booster fan are combined, eliminating the desulfurization booster fan and increasing the induced draft fan pressure. The induced draft fan is used entirely to overcome the resistance of the entire flue gas system (including the desulfurization system), thereby reducing plant construction investment and operating power consumption. Simultaneously, the first and second electric dampers are activated in stages when switching the desulfurization unit's operating status. For example, if the desulfurization unit malfunctions or is burning low-sulfur coal, when switching the desulfurization unit from operating to non-operating status, the second electric damper is activated first to gradually open the bypass flue. During this gradual opening, the first electric damper is then activated to gradually close the exhaust pipe. Conversely, when the desulfurization unit needs to be used, the first electric damper is activated first to gradually open the exhaust pipe. During this gradual opening, the second electric damper is then activated to gradually close the bypass flue. This reduces pressure fluctuations in the boiler furnace when using the combined induced draft and booster fan, preventing boiler shutdown accidents. Attached Figure Description

[0013] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings. Wherein: Figure 1 A schematic diagram of the system structure of this utility model is shown; Figure 2 A schematic diagram of the structure of this utility model is shown; Figure 3 A schematic diagram showing the outlet pressure results of the dust collector of this utility model is displayed; In the accompanying drawings, the same parts use the same reference numerals. The drawings are not to scale.

[0014] Figure label: 1-Desulfurization device, 2-Chimney, 3-First electric damper, 4-Second electric damper, 5-Exhaust pipe, 6-Bypass flue, 7-Exhaust fan, 8-Dust collector. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] Currently, large-scale coal-fired power plants both domestically and internationally have widely adopted the "integrated induced draft fan and desulfurization unit booster fan" approach. This involves merging the boiler's induced draft fan and the desulfurization unit's booster fan into a single, higher-lift fan. The induced draft fan is used to overcome the resistance from the boiler to the desulfurization unit, the desulfurization system, and the chimney, thereby saving on construction costs and reducing the power plant's operating power consumption. However, the applicant has discovered that when using the "integrated induced draft fan and booster fan" technology, the resistance of the entire flue gas system (including the desulfurization system) is overcome by the induced draft fan. When switching on or off the desulfurization equipment, the resistance of the entire flue gas system changes significantly, which can easily cause the induced draft fan to overspeed or cause large fluctuations in boiler furnace pressure, potentially leading to boiler shutdown accidents.

[0017] This utility model provides a large-scale coal-fired power plant integrated desulfurization flue system, such as... Figure 1 and Figure 2 As shown, the device includes an induced draft assembly and a desulfurization device 1 connected through a flue. The air inlet of the desulfurization device 1 is connected to the air outlet of the induced draft assembly, and the air outlet of the desulfurization device 1 is connected to the chimney 2. The desulfurization device 1 is also connected in parallel with a desulfurization bypass. A first electric damper 3 is installed at both the air inlet and the air outlet of the desulfurization device 1, and a second electric damper 4 is installed on the desulfurization bypass. Both the first electric damper 3 and the second electric damper 4 are electrically connected to a controller so that the first electric damper 3 and the second electric damper 4 can be started in stages when the desulfurization device 1 switches to the operating state. It should be noted that in this embodiment, the induced draft fan and the desulfurization booster fan are combined and the desulfurization booster fan is cancelled. The air pressure of the induced draft fan 7 is increased, and the resistance of the entire flue gas system (including the desulfurization system) is overcome entirely by the induced draft fan 7. The damper can be automatically controlled when switching the desulfurization equipment on or off, or it can be manually controlled by the operator in the control room. Under normal operating conditions, the second electric damper 4 of the desulfurization bypass flue 6 is closed, and the first electric damper 3 at the inlet and outlet of the desulfurization device 1 is opened, so that the flue gas is discharged into the atmosphere through the desulfurization equipment. When switching the desulfurization device 1 on or off, the first electric damper 3 and the second electric damper 4 are started in stages and in sequence to avoid the simultaneous start of both and the resulting excessive pressure fluctuation in the furnace. Specifically, the desulfurization device 1 is connected to the induced draft assembly and the chimney 2 respectively through the flue gas pipe 5. The first electric damper 3 can completely close the flue gas pipe 5. The desulfurization bypass is connected to the induced draft assembly and the chimney 2 respectively through the bypass flue 6. The second electric damper 4 can completely close the bypass flue 6. When the desulfurization device 1 switches to the commissioning state, the first electric damper 3 or the second electric damper 4, which is in the closed state, is started first, and then the other electric damper is started after a delay. The induced draft assembly includes two induced draft fans 7 connected in parallel. The two induced draft fans 7 are also connected to a dust collector 8. It should be noted that in this embodiment, the induced draft fan 7 and the desulfurization booster fan are combined into a single induced draft fan 7, eliminating the desulfurization booster fan. This increases the air pressure of the induced draft fan 7, allowing it to overcome the resistance of the entire flue gas system (including the desulfurization system) entirely, thereby reducing plant construction investment and operating power consumption. Simultaneously, the first electric damper 3 and the second electric damper 4 are activated in stages when switching the operation status of the desulfurization device 1. For example, if the desulfurization device 1 malfunctions or is burning low-sulfur coal, the desulfurization device 1 switches from the operating state to the non-operating state. Initially, the first electric damper 3 at the air inlet and outlet of the desulfurization device 1 is fully open, while the second electric damper 4 is fully closed. The bypass flue 6 is opened by first activating the second electric damper 4, gradually opening the bypass flue 6. During this opening process, the first electric damper 3 is then activated, gradually closing the exhaust pipe 5. If the desulfurization unit 1 is required, the initial state is that the first electric damper 3 at the inlet and outlet of the desulfurization unit 1 is completely closed, and the second electric damper 4 of the bypass flue 6 is fully open. That is, the first electric damper 3 is activated first, gradually opening the exhaust pipe 5. During this opening process, the second electric damper 4 is then activated, gradually closing the bypass flue 6. This reduces pressure fluctuations in the boiler furnace and prevents boiler shutdown accidents when using the combined induced draft fan. Figure 3The diagram shows the outlet pressure results of dust collector 8. Under different conditions, the specific timing of the step-by-step delayed start-up will affect the pressure fluctuation in the furnace. Therefore, finite element analysis can be used to model the flue from the outlet of dust collector 8 to the inlet of chimney 2. The desulfurization device 1 is simplified using components with equal resistance. During the experiment, multiple sets of comparative tests can be set, such as delay times of 5s, 10s, and 15s, to compare the flow field and outlet pressure of dust collector 8 under different delay times. The most stable value of the outlet pressure change of dust collector 8 is taken as the delay time. If the desulfurization device 1 fails or low-sulfur coal is burned, the desulfurization device 1 is switched from the operation state to the non-operation state. The initial state is that the first electric damper 3 at the air inlet and air outlet of the desulfurization device 1 is fully open, while the second electric damper 4 is completely closed to the bypass flue 6. That is, the second electric damper 4 is started first to gradually open the bypass flue 6. After the second electric damper 4 is started for 10 seconds, the first electric damper 3 is started after a delay to gradually close the exhaust pipe 5.

[0018] In one embodiment, the second electric baffle 4 is located between the two first electric baffles 3, so that when the first electric baffles 3 and the second electric baffle 4 are started in stages, the impact on furnace pressure fluctuation is reduced. In one embodiment, such as Figure 1 and Figure 2 As shown, the induced draft assembly includes two induced draft fans 7 connected in parallel. The two induced draft fans 7 are also connected to a dust collector 8. The chimney 2 is connected to two coal-fired power units. Each coal-fired power unit includes an induced draft assembly and a desulfurization device 1. The two coal-fired power units are symmetrically arranged on both sides of the chimney 2, which increases the fault tolerance of the system to ensure the normal power generation of the coal-fired power plant.

[0019] In the description of this utility model, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0020] While specific embodiments of the present invention have been described herein with reference to them, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A large-scale coal-fired power plant integrated flue gas desulfurization system, characterized in that, The device includes an induced draft assembly and a desulfurization unit connected via a flue. The air inlet of the desulfurization unit is connected to the air outlet of the induced draft assembly, and the air outlet of the desulfurization unit is connected to a chimney. The desulfurization unit is also connected in parallel with a desulfurization bypass. A first electric damper is installed at both the air inlet and the air outlet of the desulfurization unit, and a second electric damper is installed on the desulfurization bypass. Both the first and second electric dampers are electrically connected to a controller so that the first and second electric dampers can be activated in stages when the desulfurization unit switches between operating states.

2. The integrated flue gas desulfurization system for a large-scale coal-fired power plant according to claim 1, characterized in that, The desulfurization device is connected to the induced draft assembly and the chimney via a flue gas pipeline, and the first electric damper can completely seal the flue gas pipeline.

3. The integrated desulfurization flue system for a large-scale coal-fired power plant according to claim 2, characterized in that, The desulfurization bypass is connected to the induced draft assembly and the chimney via a bypass flue, and the second electric damper can completely seal the bypass flue.

4. The integrated flue gas desulfurization system for a large-scale coal-fired power plant according to claim 1, characterized in that, The second electric baffle is located between the two first electric baffles.

5. A large-scale coal-fired power plant integrated desulfurization flue system according to claim 1, characterized in that, The air intake assembly includes two exhaust fans connected in parallel, and the two exhaust fans are also connected to a dust collector.

6. A large-scale coal-fired power plant integrated desulfurization flue system according to claim 1, characterized in that, The chimney is connected to two coal-fired power units, and each coal-fired power unit includes the induced draft assembly and the desulfurization device.

7. A large-scale coal-fired power plant integrated desulfurization flue system according to claim 6, characterized in that, The two coal-fired units are symmetrically arranged on both sides of the chimney.

8. A large-scale coal-fired power plant integrated desulfurization flue system according to claim 3, characterized in that, When the desulfurization device switches between operating states, it first activates the first or second electric damper that is in a closed state, and then delays the activation of the other electric damper.

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