Load self-adaptive low-temperature economizer ash removal device and ash removal method thereof

Abstract

The invention discloses a load self-adaptive low-temperature coal economizer ash removal device and an ash removal method thereof, and aims to provide a load self-adaptive low-temperature coal economizer ash removal device which can remove accumulated ash at the bottom of a low-temperature coal economizer by using the power of flue gas under the condition of not additionally consuming steam or compressed air energy, can adjust the ash removal strength according to the load of a unit, and improves the ash removal efficiency. Therefore, the problem of dust accumulation at the bottom of the low-temperature economizer is effectively solved. The load self-adaptive low-temperature economizer ash removal device comprises an adjusting door arranged in a flue, and the adjusting door is located in front of an inlet of a low-temperature economizer and close to the low-temperature economizer; and the driving executing mechanism is used for adjusting the circulation sectional area of the flue by driving the adjusting door so as to adjust the flow speed of the flue gas entering the inlet of the low-temperature economizer.

Description

Technical Field

[0001] The present invention relates to the technical field of soot cleaning for low-temperature economizers applied in coal-fired power plants, and particularly relates to a load-adaptive low-temperature economizer soot cleaning device and a soot cleaning method thereof. Background Art

[0002] In coal-fired power plants, low-temperature economizers, as waste heat recovery devices for flue gas, have been widely used. However, since most low-temperature economizers are installed in horizontal flue ducts and there is a large amount of ash in the flue gas, the problem of ash accumulation is inevitably encountered. Especially when future thermal power plants need to participate in peak shaving more, the problem of ash accumulation in the flue duct and low-temperature economizer will become more and more serious. Specifically, When a thermal power plant participates in peak shaving, when the power plant operates at full load, due to the large amount of flue gas, the flue gas flow velocity in the flue duct and the low-temperature economizer is relatively high, and ash particles flow with the flue gas and usually do not accumulate ash. However, when the load condition of the thermal power generation unit decreases, the amount of flue gas will decrease accordingly, resulting in a slowdown of the flue gas flow velocity in the flue duct, and the dust particles carried in the flue gas will be deposited in the flue duct and also in the low-temperature economizer. In some power plants with serious ash accumulation, the ash accumulation depth at the bottom of the low-temperature economizer even reaches more than 1 meter. The direct consequence of ash accumulation in the low-temperature economizer is that the heating surface at the bottom of the low-temperature economizer is buried by fly ash, resulting in the inability of this part of the heat transfer area to participate in heat transfer, seriously affecting the effect of waste heat recovery; moreover, after the fly ash is deposited for a long time, a series of problems such as caking and corrosion of heat exchange tubes will occur. This is a difficult problem faced by all coal-fired power plants with horizontally arranged low-temperature economizers at present.

[0003] Currently, for the ash accumulation of low-temperature economizers, steam soot blowing or acoustic soot blowing methods are usually adopted. The limitations of these two methods are as follows: 1. The soot cleaning effect is limited. The soot blower can usually only blow away some of the fly ash sticking to the heat transfer surface tube wall of the low-temperature economizer, and cannot solve the problem that the heat exchange tubes at the bottom of the low-temperature economizer are buried by fly ash. 2. A large amount of steam energy or a large amount of compressed air energy needs to be consumed additionally, resulting in energy waste.

[0004] For example, Chinese Patent Publication No. CN117128531A, the name of the invention is, this application discloses a low-low temperature economizer, which adopts a vertical arrangement to solve the problem of easy ash accumulation at the bottom of the low-temperature economizer; however, the currently horizontally arranged low-temperature economizers still face the problem of easy ash accumulation at the bottom. Summary of the Invention

[0005] The object of the present invention is to provide a load - adaptive soot - cleaning device for a low - temperature economizer and its soot - cleaning method, which can utilize the self - power of flue gas to remove the ash accumulated at the bottom of the low - temperature economizer without additional consumption of steam or compressed - air energy, and can also adjust the soot - cleaning intensity according to the unit load, thus effectively solving the problem of ash accumulation at the bottom of the low - temperature economizer.

[0006] The technical solution of the present invention is as follows: A load - adaptive soot - cleaning device for a low - temperature economizer, comprising: A regulating gate, which is arranged in the flue, and the regulating gate is located in front of the inlet of the low - temperature economizer and close to the low - temperature economizer; A driving actuator, which drives the regulating gate to adjust the cross - sectional area of the flue flow, so as to adjust the flue - gas flow velocity entering the inlet of the low - temperature economizer. The load - adaptive soot - cleaning device of this solution can match the corresponding soot - cleaning intensity according to the unit load. Without consuming steam or compressed - air porosity, by using the head of the induced draft fan itself, the low - temperature economizer is soot - cleaned by adjusting the flue - gas flow velocity under different unit - load conditions. It has a simple system, low energy consumption, solves the stubborn problem of long - term ash accumulation at the bottom of the low - temperature economizer under low - load conditions, improves the heat - transfer capacity of the low - temperature economizer, and also reduces the corrosion of the low - temperature economizer. Specifically, According to the actual load condition of the unit where the low - temperature economizer is located, the driving actuator drives the regulating gate to adjust the cross - sectional area of the flue flow, so as to adjust the flue - gas flow velocity entering the inlet of the low - temperature economizer. For example, when the actual load condition of the unit decreases and the flue - gas volume in the flue decreases, the driving actuator drives the regulating gate to reduce the cross - sectional area of the flue flow, thereby increasing the flue - gas flow velocity entering the inlet of the low - temperature economizer, forming a high - speed flue - gas corridor at the bottom of the low - temperature economizer, washing away the ash at the bottom. Its soot - cleaning effect is good, and it can soot - clean the low - temperature economizer in all directions along the gas - flow direction. The soot - cleaning range covers the entire bottom space of the low - temperature economizer, thus solving the problem of ash accumulation at the bottom of the low - temperature economizer, ensuring the heat - transfer effect of the low - temperature economizer, and also reducing the corrosion of the low - temperature economizer, helping the power plant to save energy and increase efficiency.

[0007] At the same time, the load - adaptive soot - cleaning device of this solution adjusts the flue - gas flow velocity entering the inlet of the low - temperature economizer by adjusting the cross - sectional area of the flue flow. It uses the self - power of the flue gas to blow away the ash, without additional consumption of steam or compressed - air energy, so the soot - cleaning energy consumption is extremely low.

[0008] Preferably, the regulating door is rotatably arranged at the top of the inner wall of the flue through a rotating shaft. When the driving actuator drives the regulating door to rotate downward around the rotating shaft, the regulating door reduces the cross-sectional area of the flue flow from top to bottom, thereby increasing the flue gas flow velocity at the bottom of the flue. Since the ash accumulation at the bottom of the low-temperature economizer is located at the bottom of the flue, in this solution, the regulating door is rotatably arranged at the top of the inner wall of the flue through a rotating shaft, and the regulating door reduces the cross-sectional area of the flue flow from top to bottom, thereby increasing the flue gas flow velocity at the bottom of the flue, forming a high-speed flue gas corridor at the bottom of the flue to wash away the ash accumulation at the bottom of the low-temperature economizer. Its ash cleaning effect is good, and it can clean the low-temperature economizer in all directions along the gas flow direction. The ash cleaning range covers the entire bottom space of the low-temperature economizer, thus solving the problem of ash accumulation at the bottom of the low-temperature economizer and ensuring the heat exchange effect of the low-temperature economizer.

[0009] Preferably, when the ash cleaning device of the load adaptive type low-temperature economizer is not operating, the driving actuator drives the regulating door to rotate upward around the rotating shaft until the regulating door abuts against the inner wall of the top of the flue. In this way, when the ash cleaning device of the load adaptive type low-temperature economizer is not operating, the regulating door is closely attached to the upper wall of the flue, hardly generating flue resistance, having no disturbance to the flue gas flow field, and having almost no impact on the operation.

[0010] Preferably, the driving actuator is an electric actuator or a pneumatic actuator. The driving actuator includes a telescopic rod. The driving actuator is fixed on the flue, and a slider that slides radially along the rotating shaft is arranged on the regulating door. One end of the telescopic rod is hinged to the slider. In this way, during the extension process of the telescopic rod of the driving actuator, the regulating door will be driven to rotate downward around the rotating shaft, and the regulating door reduces the cross-sectional area of the flue flow from top to bottom, thereby increasing the flue gas flow velocity at the bottom of the flue. During the contraction process of the telescopic rod of the driving actuator, the regulating door will be driven to rotate upward around the rotating shaft until the regulating door abuts against the inner wall of the top of the flue.

[0011] Preferably, the driving actuator is an electric actuator or a pneumatic actuator. The driving actuator includes a telescopic rod. The driving actuator is hinged on the flue, and one end of the telescopic rod is hinged to the regulating door. In this way, during the extension process of the telescopic rod of the driving actuator, the regulating door will be driven to rotate downward around the rotating shaft, and the regulating door reduces the cross-sectional area of the flue flow from top to bottom, thereby increasing the flue gas flow velocity at the bottom of the flue. During the contraction process of the telescopic rod of the driving actuator, the regulating door will be driven to rotate upward around the rotating shaft until the regulating door abuts against the inner wall of the top of the flue.

[0012] Preferably, the driving actuator is an electric actuator or a pneumatic actuator. The driving actuator includes a telescopic rod. The driving actuator is fixed on the flue. The adjusting door is provided with a waist-shaped hole extending radially along the rotating shaft. The lower end of the telescopic rod passes through the waist-shaped hole, and a limiting block is provided at the lower end of the telescopic rod. The adjusting door abuts against the limiting block under its own weight. In this way, during the extension process of the telescopic rod of the driving actuator, the adjusting door will rotate downward around the rotating shaft under its own weight (the adjusting door remains in contact with the limiting block under its own weight), and the adjusting door will reduce the flue flow cross-sectional area from top to bottom, thereby increasing the flue gas flow velocity at the bottom of the flue. During the contraction process of the telescopic rod of the driving actuator, the adjusting door will be driven to rotate upward around the rotating shaft until the adjusting door abuts against the inner wall of the top of the flue.

[0013] Preferably, the driving actuator is located above the adjusting door, and the driving actuator and the low-temperature economizer are on the same side of the adjusting door. In this way, the driving actuator will be located on the leeward side of the adjusting door, and the adjusting door will block the dust particles in the flue gas, avoiding the dust particles in the flue gas from scratching the driving actuator and effectively reducing the corrosion of the driving actuator by the flue gas, thereby effectively improving the service life of the driving actuator.

[0014] Preferably, the distance between the adjusting door and the inlet of the low-temperature economizer is 2-3 meters.

[0015] A soot cleaning method for a load adaptive type low-temperature economizer soot cleaning device includes the following steps. According to the load condition of the unit where the low-temperature economizer is located, set n soot cleaning gear commands C1-Cn, and the load conditions of the units corresponding to the n soot cleaning gear commands C1-Cn gradually decrease. Among them, C1 corresponds to the unit load condition of 100%THA. Each soot cleaning gear command in C1-Cn includes a soot cleaning intensity, and the soot cleaning intensities of the n soot cleaning gear commands C1-Cn gradually increase. The soot cleaning intensity is controlled by driving the adjusting door through the driving actuator to adjust the flue flow cross-sectional area; the smaller the flue flow cross-sectional area, the stronger the soot cleaning intensity. The soot cleaning method of this solution sets n soot cleaning gear commands C1-Cn according to the load condition of the unit where the low-temperature economizer is located. Each soot cleaning gear command corresponds to a different unit load condition. The smaller the unit load condition, the stronger the soot cleaning intensity included in the soot cleaning gear command. Thus, a high-speed flue gas corridor is formed at the bottom of the low-temperature economizer to wash away the bottom ash, effectively solving the problem of bottom ash accumulation in the low-temperature economizer, ensuring the heat transfer effect of the low-temperature economizer, and also reducing problems such as corrosion of the low-temperature economizer, helping the power plant to save energy and increase efficiency.

[0016] Preferably, in the n ash cleaning gear commands of C1 - Cn, the load - adaptive low - temperature economizer ash cleaning device operates intermittently. Specifically, each ash cleaning gear command in C1 - Cn also includes an ash cleaning duration and an ash cleaning frequency. The ash cleaning duration refers to the single - time ash cleaning time, and the ash cleaning frequency is the ash cleaning interval time. In the ash cleaning gear commands of this solution, the load - adaptive low - temperature economizer ash cleaning device adopts an intermittent working mode. By controlling the ash cleaning duration and the ash cleaning frequency, the ash cleaning effect on the ash accumulation at the bottom of the low - temperature economizer is further ensured.

[0017] The beneficial effects of the present invention are as follows: It does not consume additional energy, cleverly utilizes the self - power of the flue gas for ash cleaning, does not consume additional steam or compressed air, and reduces the operation cost of the power plant.

[0018] The ash cleaning effect is good. It can clean the low - temperature economizer comprehensively in the air flow direction, and the ash cleaning range covers the entire bottom space of the low - temperature economizer. It also specifically solves the problem of ash burial at the bottom of the low - temperature economizer when the unit load condition decreases, ensures the heat exchange effect of the low - temperature economizer, and reduces the risks of ash deposition and corrosion at the bottom of the low - temperature economizer.

[0019] It is adaptively adjusted according to the unit load condition, can achieve automatic ash cleaning under different unit load conditions, and the ash cleaning intensity, ash cleaning duration and ash cleaning frequency can all be automatically adjusted according to the unit load.

[0020] It has little interference to the original system. The system is simple. When the load - adaptive low - temperature economizer ash cleaning device is not operating, it has no interference to the flue gas flow field of the flue duct and the low - temperature economizer, and does not generate additional resistance.

[0021] The present invention utilizes the self - power of the flue gas to remove the ash accumulation at the bottom of the low - temperature economizer, which not only ensures the heat exchange effect of the low - temperature economizer, but also reduces the risks of scaling, corrosion and wear of the low - temperature economizer, reduces the maintenance workload of the power plant operation personnel for the equipment, and plays a great role in the safe and reliable operation and energy conservation and efficiency improvement of the power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of the load - adaptive low - temperature economizer ash cleaning device of the present invention.

[0023] In the figure: regulating door 1, driving actuator 2, flue duct 3, low - temperature economizer 4. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention will be further described in detail below in conjunction with the drawings and the specific embodiments: Specific Embodiment 1, as Figure 1 shown, a load - adaptive low - temperature economizer ash cleaning device includes a regulating door 1 and a driving actuator 2.

[0025] The regulating door 1 is arranged in the flue duct 3. The regulating door 1 is located in front of the inlet of the low-temperature economizer 4 and close to the low-temperature economizer. In this embodiment, the distance between the regulating door 1 and the inlet of the low-temperature economizer is 2-3 meters.

[0026] The driving actuator 2 is used to drive the regulating door 1. By driving the regulating door 1, the driving actuator 2 adjusts the cross-sectional area of the flue duct flow to adjust the flue gas flow velocity entering the inlet of the low-temperature economizer.

[0027] The ash cleaning device of the load-adaptive low-temperature economizer in this embodiment can match the corresponding ash cleaning intensity according to the unit load. Without consuming steam or compressed air porosity, using the head of the induced draft fan itself, the low-temperature economizer is ash-cleaned by adjusting the flue gas flow velocity under different load conditions of the unit. It has a simple system and low energy consumption, solves the stubborn problem of long-term ash accumulation at the bottom of the low-temperature economizer under low load conditions, improves the heat transfer capacity of the low-temperature economizer, and also reduces the corrosion of the low-temperature economizer and other problems. Specifically, The ash cleaning device of the load-adaptive low-temperature economizer in this embodiment adjusts the cross-sectional area of the flue duct flow through the driving actuator 2 to drive the regulating door 1 according to the actual load condition of the unit where the low-temperature economizer is located, so as to adjust the flue gas flow velocity entering the inlet of the low-temperature economizer. For example, when the actual load condition of the unit decreases and the flue gas volume in the flue duct decreases, the driving actuator 2 drives the regulating door 1 to reduce the cross-sectional area of the flue duct flow, thereby increasing the flue gas flow velocity entering the inlet of the low-temperature economizer, forming a high-speed flue gas corridor at the bottom of the low-temperature economizer, washing away the bottom ash. Its ash cleaning effect is good, and it can clean the low-temperature economizer in all directions along the gas flow direction. The ash cleaning range covers the entire bottom space of the low-temperature economizer, thus solving the problem of ash accumulation at the bottom of the low-temperature economizer, ensuring the heat transfer effect of the low-temperature economizer, and also reducing the corrosion of the low-temperature economizer and other problems, helping the power plant to save energy and increase efficiency.

[0028] At the same time, the ash cleaning device of the load-adaptive low-temperature economizer in this embodiment adjusts the cross-sectional area of the flue duct flow to adjust the flue gas flow velocity entering the inlet of the low-temperature economizer. It uses the self-power of the flue gas to blow away the ash, without additional consumption of steam or compressed air energy, so the ash cleaning energy consumption is extremely low.

[0029] Specific Embodiment 2, as Figure 1 shown, a load-adaptive low-temperature economizer ash cleaning device includes a regulating door 1 and a driving actuator 2.

[0030] The regulating door 1 is arranged in the flue duct 3. The regulating door 1 is located in front of the inlet of the low-temperature economizer 4 and close to the low-temperature economizer. In this embodiment, the distance between the regulating door 1 and the inlet of the low-temperature economizer is 2-3 meters.

[0031] The driving actuator 2 is used to drive the regulating door 1. By driving the regulating door 1, the driving actuator 2 adjusts the cross-sectional area of the flue passage to regulate the flue gas flow velocity at the inlet of the low-temperature economizer.

[0032] In this embodiment, the regulating door 1 is rotatably arranged at the top of the inner wall of the flue 3 through a rotating shaft, and the rotating shaft is arranged at the top of the inner wall of the flue. When the driving actuator 2 drives the regulating door 1 to rotate downward around the rotating shaft, the regulating door 1 reduces the cross-sectional area of the flue passage from top to bottom, thereby increasing the flue gas flow velocity at the bottom of the flue. Since the ash accumulation at the bottom of the low-temperature economizer is located at the bottom of the flue, in this embodiment, the regulating door 1 is rotatably arranged at the top of the inner wall of the flue through a rotating shaft, and the regulating door 1 reduces the cross-sectional area of the flue passage from top to bottom, thereby increasing the flue gas flow velocity at the bottom of the flue, forming a high-speed flue gas corridor at the bottom of the flue to wash away the ash accumulation at the bottom of the low-temperature economizer.

[0033] In this embodiment, when the ash cleaning device of the load-adaptive low-temperature economizer is not operating, the driving actuator 2 drives the regulating door 1 to rotate upward around the rotating shaft until the regulating door 1 abuts against the inner wall of the top of the flue. In this way, when the ash cleaning device of the load-adaptive low-temperature economizer is not operating, the regulating door 1 is closely attached to the upper wall of the flue, hardly generating flue resistance, having no disturbance to the flue gas flow field, and having almost no impact on the operation.

[0034] The ash cleaning device of the load-adaptive low-temperature economizer in this embodiment can match the corresponding ash cleaning intensity according to the unit load. Without consuming steam or compressed air porosity, by using the head of the induced draft fan itself, the low-temperature economizer is cleaned by adjusting the flue gas flow velocity under different unit load conditions. It has a simple system and low energy consumption, solves the stubborn problem of long-term ash accumulation at the bottom of the low-temperature economizer under low load conditions, improves the heat transfer capacity of the low-temperature economizer, and also reduces the corrosion of the low-temperature economizer. Specifically, The ash cleaning device of the load-adaptive low-temperature economizer in this embodiment adjusts the cross-sectional area of the flue passage by driving the regulating door 1 through the driving actuator 2 according to the actual load condition of the unit where the low-temperature economizer is located, so as to regulate the flue gas flow velocity at the inlet of the low-temperature economizer. For example, when the actual load condition of the unit decreases and the amount of flue gas in the flue decreases, the driving actuator 2 drives the regulating door 1 to reduce the cross-sectional area of the flue passage, thereby increasing the flue gas flow velocity at the inlet of the low-temperature economizer, forming a high-speed flue gas corridor at the bottom of the low-temperature economizer to wash away the bottom ash. Its ash cleaning effect is good, and it can clean the low-temperature economizer in all directions along the gas flow direction. The ash cleaning range covers the entire bottom space of the low-temperature economizer, thus solving the problem of ash accumulation at the bottom of the low-temperature economizer, ensuring the heat transfer effect of the low-temperature economizer, and also reducing the corrosion of the low-temperature economizer, helping the power plant to save energy and increase efficiency.

[0035] Meanwhile, the ash cleaning device of the load adaptive low-temperature economizer in this embodiment adjusts the flue gas flow velocity at the inlet of the low-temperature economizer by adjusting the cross-sectional area of the flue passage. It uses the self-power of the flue gas to blow away the accumulated ash without additional consumption of steam or compressed air energy, so the ash cleaning energy consumption is extremely low.

[0036] In this embodiment, as Figure 1 shown, the driving actuator 2 is located above the regulating door 1, and the driving actuator 2 and the low-temperature economizer are on the same side of the regulating door 1. In this way, the driving actuator 2 will be on the leeward side of the regulating door 1, and the regulating door 1 is used to block the dust particles in the flue gas, avoiding the dust particles in the flue gas from scratching the driving actuator 2 and effectively reducing the corrosion of the flue gas on the driving actuator 2, thereby effectively improving the service life of the driving actuator 2.

[0037] Of course, it should be noted that the driving actuator 2 can also be arranged below the regulating door 1 to drive the regulating door 1 through the driving actuator 2 to adjust the cross-sectional area of the flue passage.

[0038] In this embodiment, the driving actuator 2 is an electric actuator or a pneumatic actuator. For example, the driving actuator 2 is an electric cylinder, an electric push rod, a cylinder, an oil cylinder, a linear mode or other linear driving actuators on the market.

[0039] In an implementation manner of this embodiment, the driving actuator 2 is an electric cylinder, an electric push rod, a cylinder or an oil cylinder, and the driving actuator 2 includes a telescopic rod. The driving actuator 2 is fixed on the flue, and a slider that slides radially along the rotating shaft is provided on the regulating door 1. One end of the telescopic rod is hinged to the slider. In this way, during the extension process of the telescopic rod of the driving actuator 2, the regulating door 1 will be driven to rotate downward around the rotating shaft, and the regulating door 1 will reduce the cross-sectional area of the flue passage from top to bottom, thereby increasing the flue gas flow velocity at the bottom of the flue. During the contraction process of the telescopic rod of the driving actuator 2, the regulating door 1 will be driven to rotate upward around the rotating shaft until the regulating door 1 abuts against the inner wall of the top of the flue.

[0040] In this implementation manner, the telescopic rod of the driving actuator 2 extends into the flue, and the remaining parts of the driving actuator 2 can be installed and arranged as needed. For example, the remaining parts of the driving actuator 2 are installed outside the flue; or a part of the remaining parts of the driving actuator 2 is located inside the flue and the other part is installed outside the flue; or the remaining parts of the driving actuator 2 are also installed inside the flue.

[0041] In another implementation of this embodiment, the driving actuator 2 is an electric cylinder, an electric push rod, a pneumatic cylinder or a hydraulic cylinder, and the driving actuator 2 includes a telescopic rod. The driving actuator 2 is hinged to the flue, and one end of the telescopic rod is hinged to the regulating door 1. In this way, during the extension process of the telescopic rod of the driving actuator 2, the regulating door 1 will be driven to rotate downward around the rotating shaft, and the regulating door 1 will reduce the cross-sectional area of the flue flow from top to bottom, thereby increasing the flue gas flow velocity at the bottom of the flue. During the contraction process of the telescopic rod of the driving actuator 2, the regulating door 1 will be driven to rotate upward around the rotating shaft until the regulating door 1 abuts against the inner wall of the top of the flue.

[0042] In this implementation, the telescopic rod of the driving actuator 2 extends into the flue, and the remaining parts of the driving actuator 2 can be installed and arranged as required. For example, the remaining parts of the driving actuator 2 are installed outside the flue; or a part of the remaining parts of the driving actuator 2 is located inside the flue and the other part is installed outside the flue; or the remaining parts of the driving actuator 2 are also installed inside the flue.

[0043] In the third implementation of this embodiment, the driving actuator 2 is an electric cylinder, an electric push rod, a pneumatic cylinder or a hydraulic cylinder, and the driving actuator 2 includes a telescopic rod. The driving actuator 2 is fixed to the flue, and the regulating door 1 is provided with a waist-shaped hole extending radially along the rotating shaft. The lower end of the telescopic rod passes through the waist-shaped hole, and a limit block is provided at the lower end of the telescopic rod. The regulating door 1 abuts against the limit block under its own weight. In this way, during the extension process of the telescopic rod of the driving actuator 2, the regulating door 1 will rotate downward around the rotating shaft under its own weight (the regulating door 1 remains in contact with the limit block under its own weight), and the regulating door 1 will reduce the cross-sectional area of the flue flow from top to bottom, thereby increasing the flue gas flow velocity at the bottom of the flue. During the contraction process of the telescopic rod of the driving actuator 2, the regulating door 1 will be driven to rotate upward around the rotating shaft until the regulating door 1 abuts against the inner wall of the top of the flue.

[0044] In this implementation, the telescopic rod of the driving actuator 2 extends into the flue, and the remaining parts of the driving actuator 2 can be installed and arranged as required. For example, the remaining parts of the driving actuator 2 are installed outside the flue; or a part of the remaining parts of the driving actuator 2 is located inside the flue and the other part is installed outside the flue; or the remaining parts of the driving actuator 2 are also installed inside the flue.

[0045] The ash cleaning device of the load adaptive type low temperature economizer in this embodiment has the following beneficial effects: It does not consume additional energy, cleverly uses the power of the flue gas itself for ash cleaning, does not consume additional steam or compressed air, and reduces the operation cost of the power plant.

[0046] It has good soot cleaning effect, can clean the low-temperature economizer all-round along the gas flow direction, and the soot cleaning range covers the entire bottom space of the low-temperature economizer; and it specifically solves the problem of buried ash at the bottom of the low-temperature economizer when the unit load condition decreases, ensures the heat transfer effect of the low-temperature economizer, and reduces the risks of ash fouling and corrosion at the bottom of the low-temperature economizer.

[0047] It is adaptively adjusted according to the unit load condition, can achieve automatic soot cleaning under different unit load conditions, and the soot cleaning intensity, soot cleaning duration and soot cleaning frequency can all be automatically adjusted according to the unit load.

[0048] It has little interference to the original system, the system is simple, and when the soot cleaning device of the load-adaptive low-temperature economizer is not running, it has no interference to the flue gas flow field of the flue and the low-temperature economizer and does not generate additional resistance.

[0049] The present invention uses the self-power of the flue gas to remove the ash accumulated at the bottom of the low-temperature economizer, which not only ensures the heat transfer effect of the low-temperature economizer, but also reduces the risks of scaling, corrosion and wear of the low-temperature economizer, reduces the maintenance workload of the power plant operation personnel for the equipment, and plays a great role in the safe and reliable operation and energy conservation and efficiency improvement of the power plant.

[0050] Specific embodiment three, a soot cleaning method of a load-adaptive low-temperature economizer soot cleaning device, and the specific structure of the load-adaptive low-temperature economizer soot cleaning device in this soot cleaning method refers to specific embodiment two.

[0051] A soot cleaning method of a load-adaptive low-temperature economizer soot cleaning device includes the following steps. According to the load condition of the unit where the low-temperature economizer is located, set n soot cleaning gear commands C1 - Cn, and the unit load conditions corresponding to the n soot cleaning gear commands C1 - Cn gradually decrease. Among them, C1 corresponds to the unit load condition of 100% THA (THA in the text refers to the heat rate acceptance condition of the unit). Each soot cleaning gear command in C1 - Cn includes the soot cleaning intensity (the soot cleaning intensity in the text refers to the soot cleaning intensity of the load-adaptive low-temperature economizer soot cleaning device), and the soot cleaning intensities of the n soot cleaning gear commands C1 - Cn gradually increase. The soot cleaning intensity is controlled by driving the actuator 2 to drive the regulating door 1 to adjust the flue gas flow cross-sectional area, and the smaller the flue gas flow cross-sectional area, the stronger the soot cleaning intensity.

[0052] In an example of this embodiment, according to the load condition of the unit where the low-temperature economizer is located, set 6 soot cleaning gear commands C1 - C6, among which, The C1 soot cleaning gear command corresponds to the unit load condition of 100% THA (that is, the unit load condition is full load operation); The C2 soot cleaning gear command corresponds to the unit load condition of 90% THA; The unit load condition corresponding to the C3 soot cleaning gear position command is 75% THA; The unit load condition corresponding to the C4 soot cleaning gear position command is 50% THA; The unit load condition corresponding to the C5 soot cleaning gear position command is 40% THA; The unit load condition corresponding to the C6 soot cleaning gear position command is 30% THA.

[0053] Each soot cleaning gear position command in C1 - C6 includes the soot cleaning intensity, and the soot cleaning intensities of these 6 soot cleaning gear position commands from C1 to C6 gradually increase. The soot cleaning intensity is controlled by driving the actuator 2 to drive the regulating door 1 to adjust the flue gas flow cross-sectional area. The smaller the flue gas flow cross-sectional area, the stronger the soot cleaning intensity. For example, In the C1 soot cleaning gear position command, the regulating door 1 abuts against the inner wall of the top of the flue; In the C2 soot cleaning gear position command, the inclination angle of the regulating door 1 is 8 - 10 degrees; In the C3 soot cleaning gear position command, the inclination angle of the regulating door 1 is 15 - 20 degrees; In the C4 soot cleaning gear position command, the inclination angle of the regulating door 1 is 25 - 30 degrees; In the C5 soot cleaning gear position command, the inclination angle of the regulating door 1 is 35 - 40 degrees; In the C6 soot cleaning gear position command, the inclination angle of the regulating door 1 is 45 - 50 degrees.

[0054] In this embodiment, each soot cleaning gear position command needs to ensure that under the corresponding working conditions, after executing the corresponding soot cleaning gear position command, the flue gas flow velocity entering the low-temperature economizer is not lower than the set flow velocity (for example, the flue gas flow velocity is not lower than 8 m / s), so as to ensure the soot cleaning effect.

[0055] During the operation of the unit, when the unit starts to reduce the load, for example, when the unit load condition drops to 90% THA, a signal to execute the C2 soot cleaning gear position command will be sent to the actuator. The corresponding soot cleaning intensity has been preset in the C2 soot cleaning gear position command. After receiving the command, the actuator drives the actuator 2 to drive the regulating door 1 to rotate, so that the inclination angle of the regulating door 1 is 8 - 10 degrees, thereby reducing the flue gas flow cross-sectional area and increasing the flue gas flow velocity at the inlet of the low-temperature economizer to wash away the bottom ash accumulation.

[0056] When the unit load condition drops to 50% THA, a signal to execute the C4 soot cleaning gear position command will be sent to the actuator. The corresponding soot cleaning intensity has been preset in the C4 soot cleaning gear position command. After receiving the command, the actuator drives the actuator 2 to drive the regulating door 1 to rotate, so that the inclination angle of the regulating door 1 is 25 - 30 degrees, thereby reducing the flue gas flow cross-sectional area and increasing the flue gas flow velocity at the inlet of the low-temperature economizer to wash away the bottom ash accumulation.

[0057] The soot blowing method of this embodiment sets six soot blowing gear commands C1 - C6 according to the load condition of the unit where the low-temperature economizer is located. Each soot blowing gear command corresponds to a different unit load condition. The smaller the unit load condition, the stronger the soot blowing intensity included in the soot blowing gear command, so as to form a high-speed flue gas corridor at the bottom of the low-temperature economizer, wash away the accumulated ash at the bottom, effectively solve the problem of accumulated ash at the bottom of the low-temperature economizer, ensure the heat exchange effect of the low-temperature economizer, and also reduce problems such as corrosion of the low-temperature economizer, helping the power plant to save energy and increase efficiency.

[0058] Specific embodiment four, a soot blowing method for a load-adaptive low-temperature economizer soot blowing device. The remaining steps in this soot blowing method refer to specific embodiment three. The difference is that In the n soot blowing gear commands C1 - Cn, the load-adaptive low-temperature economizer soot blowing device operates intermittently.

[0059] Specifically, each soot blowing gear command in C1 - Cn also includes the soot blowing duration and the soot blowing frequency. The soot blowing duration refers to the single soot blowing time. For example, the soot blowing duration is 20s. The soot blowing frequency is the soot blowing interval time. For example, the soot blowing interval time is 5 minutes.

[0060] When the unit load condition drops to 50%THA, a signal to execute the soot blowing gear command C4 will be sent to the actuator. The corresponding soot blowing intensity, soot blowing duration, and soot blowing frequency have been preset in the C4 soot blowing gear command. After receiving the command, the actuator drives the actuator 2 to drive the regulating door 1 to rotate, so that the inclination angle of the regulating door 1 is 25 - 30 degrees. Then, the regulating door 1 maintains this angle for 20s, and then drives the actuator 2 to drive the regulating door 1 to rotate upward and abut against the inner wall of the flue duct top; then, after an interval of 5 minutes, drive the actuator 2 to drive the regulating door 1 to rotate, so that the inclination angle of the regulating door 1 is 25 - 30 degrees, and so on in a cycle.

[0061] Of course, it should be noted that when the coal type changes and the ash content in the coal quality is relatively high, the soot blowing intensity, soot blowing duration, and soot blowing frequency can be manually adjusted upward. When the ash content in the coal quality is low, the soot blowing intensity, soot blowing duration, and soot blowing frequency can be manually adjusted downward.

[0062] In the soot blowing gear command of this embodiment, the load-adaptive low-temperature economizer soot blowing device adopts an intermittent working mode, and by controlling the soot blowing duration and the soot blowing frequency, the soot blowing effect on the accumulated ash at the bottom of the low-temperature economizer is further ensured.

[0063] Specific embodiment five, a soot blowing method for a load-adaptive low-temperature economizer soot blowing device. The remaining steps in this soot blowing method refer to specific embodiment three. The difference is that In the n soot blowing gear commands C1 - Cn, the load-adaptive low-temperature economizer soot blowing device operates in a continuous working mode.

[0064] For example, when the unit load condition drops to 50% THA, a signal for sending the ash cleaning gear position command C4 will be sent to the actuator, and the corresponding ash cleaning intensity has been preset in the C4 ash cleaning gear position command. After receiving the command, the actuator drives the actuator mechanism 2 to drive the regulating door 1 to rotate, so that the inclination angle of the regulating door 1 is 25 - 30 degrees, and the regulating door 1 maintains this angle.

[0065] As described above, it is only a preferred embodiment of the present invention and does not impose any limitation on the present invention. Any simple modification, change, and equivalent transformation made to the above embodiments according to the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A load-adaptive low-temperature economizer soot cleaning device, characterized in that, Including: A regulating door, which is arranged in the flue duct. The regulating door is located in front of the inlet of the low-temperature economizer and close to the low-temperature economizer; A driving actuator, which drives the regulating door to adjust the cross-sectional area of the flue duct flow, so as to adjust the flue gas flow velocity entering the inlet of the low-temperature economizer.

2. The ash cleaning device for a load-adaptive low-temperature economizer according to claim 1, characterized in that, The regulating door is rotatably arranged at the top of the inner wall of the flue duct through a rotating shaft. When the driving actuator drives the regulating door to rotate downward around the rotating shaft, the regulating door reduces the cross-sectional area of the flue duct flow from top to bottom, thereby increasing the flue gas flow velocity at the bottom of the flue duct.

3. The ash cleaning device for a load adaptive low-temperature economizer according to claim 2, characterized in that, When the ash cleaning device of the load-adaptive low-temperature economizer is not operating, the driving actuator drives the regulating door to rotate upward around the rotating shaft until the regulating door abuts against the inner wall of the top of the flue duct.

4. The ash cleaning device for a load-adaptive low-temperature economizer according to claim 2 or 3, characterized in that, The driving actuator is an electric actuator or a pneumatic actuator. The driving actuator includes a telescopic rod. The driving actuator is fixed on the flue duct. A sliding block that slides radially along the rotating shaft is arranged on the regulating door, and one end of the telescopic rod is hinged to the sliding block.

5. The ash cleaning device for a load-adaptive low-temperature economizer according to claim 2 or 3, characterized in that, The driving actuator is an electric actuator or a pneumatic actuator. The driving actuator includes a telescopic rod. The driving actuator is hinged on the flue duct, and one end of the telescopic rod is hinged to the regulating door.

6. The ash cleaning device for a load-adaptive low-temperature economizer according to claim 2 or 3, characterized in that, The driving actuator is an electric actuator or a pneumatic actuator. The driving actuator includes a telescopic rod. The driving actuator is fixed on the flue duct. A waist-shaped hole extending radially along the rotating shaft is arranged on the regulating door. The lower end of the telescopic rod passes through the waist-shaped hole, and a limiting block is arranged at the lower end of the telescopic rod. The regulating door abuts against the limiting block under the action of its own weight.

7. The ash cleaning device for a load-adaptive low-temperature economizer according to claim 1 or 2 or 3, characterized in that, The driving actuator is located above the regulating door, and the driving actuator and the low-temperature economizer are on the same side of the regulating door.

8. The ash cleaning device for a load-adaptive low-temperature economizer according to claim 1 or 2 or 3, characterized in that, The distance between the regulating door and the inlet of the low-temperature economizer is 2 - 3 meters.

9. A soot cleaning method for the load adaptive low-temperature economizer soot cleaning device according to any one of claims 1-8, characterized in that, Including the following steps, According to the load condition of the unit where the low-temperature economizer is located, set n ash cleaning gear commands C1 - Cn, and the load conditions of the unit corresponding to the n ash cleaning gear commands C1 - Cn gradually decrease. Among them, C1 corresponds to the unit load condition of 100% THA; Each ash cleaning gear command in C1 - Cn includes an ash cleaning intensity, and the ash cleaning intensities of the n ash cleaning gear commands C1 - Cn gradually increase; The ash cleaning intensity is controlled by driving the regulating door through the driving actuator to adjust the cross-sectional area of the flue duct flow, and the smaller the cross-sectional area of the flue duct flow, the stronger the ash cleaning intensity.

10. The soot cleaning method of the load adaptive type low-temperature economizer soot cleaning device according to claim 9, characterized in that, In the n ash cleaning gear commands C1 - Cn, the ash cleaning device of the load-adaptive low-temperature economizer operates intermittently. Specifically, each ash cleaning gear command in C1 - Cn also includes an ash cleaning duration and an ash cleaning frequency. The ash cleaning duration refers to the single ash cleaning time, and the ash cleaning frequency is the ash cleaning interval time.

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