A device for regulating temperature of a final stage reheater and an operating method thereof

Abstract

The present invention discloses a device for regulating the temperature of a final stage reheater and an operating method thereof, comprising a controller, a rotating motor, a driving wheel, a driven wheel, a hydraulic cylinder, a hydraulic cylinder piston rod, a smoke shielding baffle and a power supply box for providing electric energy, wherein the smoke shielding baffle is located between a high-temperature superheater and a final stage reheater in a horizontal flue of a boiler, the output shaft of the rotating motor is connected to the driving wheel, the driving wheel cooperates with the driven wheel, the driven wheel is connected to the upper end of the smoke shielding baffle, one end of the hydraulic cylinder piston rod cooperates with the hydraulic cylinder, the other end of the hydraulic cylinder piston rod is inserted into the horizontal flue of the boiler and then connected to the smoke shielding baffle, the controller is connected to the control end of the piston cylinder and the control end of the rotating motor, the device and the operating method thereof can effectively alleviate the phenomenon of fouling and slagging of the heating surface of the final stage reheater under long-term high-load operation of the boiler, and improve the safety and reliability of the unit operation.

Description

Technical Field

[0001] The invention belongs to the technical field of temperature regulation of heating surfaces of coal-fired boilers, and relates to a device for regulating the temperature of a final-stage reheater and an operating method thereof. Background Art

[0002] In recent years, the power industry has developed rapidly, and supercritical and ultra-supercritical thermal power units have become the main units in service in my country. As power station boilers develop towards high parameters and large capacity, the steam temperature deviation and overheating of the heating surface caused by uneven combustion in the furnace are becoming increasingly serious, and have become one of the main problems affecting the safe and stable operation of the units. At the same time, due to changes in the electricity consumption structure, the continuous increase in civilian electricity consumption and the increasing peak-to-valley difference in the power grid, thermal power units will participate in more peak-shaving tasks while carrying basic loads, and frequent load increases and decreases will have an adverse effect on the regulation of steam temperature.

[0003] Uneven distribution of flue gas velocity and flue gas temperature in the heating surface area of ​​the boiler will lead to uneven heat absorption of heating surfaces such as the screen superheater, high-temperature superheater, and final reheater. Excessive steam temperature will accelerate the creep of the metal material of the heat exchanger, and cause additional thermal stress on the tube wall of the superheater and reheater, shortening the service life of the equipment. Long-term operation will cause overheating of the heating surface or even tube bursting. Excessive steam temperature will increase the humidity of the steam in the final stage of the steam turbine, aggravate the erosion of the turbine blades, and cause water hammer in severe cases. In addition, the drop in steam temperature affects the power generation efficiency of the steam turbine and increases the coal consumption of the unit. In order to control the tube wall temperature within a reasonable range, it is usually necessary to reduce the main steam temperature and reheat steam temperature. At the same time, when the flue gas temperature deviation on both sides of the boiler is large, the amount of cooling water cannot be reasonably controlled, resulting in a decrease in the overall economic efficiency of the unit.

[0004] The methods of steam temperature regulation are mainly divided into two categories: steam side regulation and flue gas side regulation. For the regulation method of the steam temperature of the final reheater, the main method is usually flue gas side regulation. Common methods include flue gas recirculation, separating flue dampers and changing the center position of the flame. At the same time, a reheater accident water spray cooler is also provided for emergency accident conditions, rapid load change conditions or other unstable conditions. The above regulation methods all have problems to varying degrees during the current operation of the unit: for example, the steam temperature regulation time lag using the flue damper method is too large, the damper opening has a nonlinear relationship with the air temperature, and the damper only has a good regulation effect within a certain opening range; the regulation method of changing the flame center has high sensitivity and small time lag, but low accuracy. Various unfavorable factors make it difficult to regulate the final reheat steam temperature during the unit's rapid load change process. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and to provide a device for regulating the temperature of a final stage reheater and an operating method thereof, which can effectively alleviate the fouling and slagging phenomenon of the heating surface of the final stage reheater under long-term high-load operation of the boiler, thereby improving the safety and reliability of the unit operation.

[0006] To achieve the above-mentioned purpose, the device for regulating the temperature of the final stage reheater described in the present invention includes a controller, a rotating motor, a driving wheel, a driven wheel, a hydraulic cylinder, a hydraulic cylinder piston rod, a smoke shielding baffle and a power supply box for providing electric energy, wherein the smoke shielding baffle is located between the high-temperature superheater and the final stage reheater in the horizontal flue of the boiler, the output shaft of the rotating motor is connected to the driving wheel, the driving wheel cooperates with the driven wheel, the driven wheel is connected to the upper end of the smoke shielding baffle, one end of the hydraulic cylinder piston rod cooperates with the hydraulic cylinder, the other end of the hydraulic cylinder piston rod is inserted into the horizontal flue of the boiler and then connected to the smoke shielding baffle, and the controller is connected to the control end of the piston cylinder and the control end of the rotating motor.

[0007] The output shaft of the rotating motor is connected to the driving wheel through a first connecting rod.

[0008] The driven wheel is connected to the upper end of the smoke shielding baffle through a second connecting rod.

[0009] The smoke shield and the connection position between the hydraulic cylinder piston rod and the boiler horizontal flue are wrapped with a layer of thermal insulation material.

[0010] The driving wheel and the driven wheel are matched with each other through threads.

[0011] An ear seat is arranged at the end of the piston rod of the hydraulic cylinder, and the ear seat is connected to the upper end of the smoke shielding baffle.

[0012] The rotating motor is fixed to the outer wall of the horizontal flue of the boiler through a power box.

[0013] The operating method of the device for adjusting the temperature of the final reheater of the present invention comprises the following steps:

[0014] When the slagging of the final stage reheater is serious, the controller controls the hydraulic cylinder to work, the hydraulic cylinder drives the hydraulic cylinder piston rod to extend, and the hydraulic cylinder piston rod drives the smoke shielding baffle to fall to the front windward side of the final stage reheater, and the smoke shielding baffle shields the high-temperature flue gas, reduces the convection heat exchange between the final stage reheater and the high-temperature flue gas, and prevents the fly ash particles and molten alkali metals in the flue gas from adhering to the heating surface tube wall of the final stage reheater, thereby reducing the contamination and slagging of the heating surface of the final stage reheater;

[0015] When the steam temperature deviation on both sides of the last stage reheater is greater than the preset value, the controller controls the hydraulic cylinder to work, the hydraulic cylinder drives the hydraulic cylinder piston rod to extend, and the hydraulic cylinder piston rod drives the smoke shield baffle to fall to the front windward side of the last stage reheater, and then controls the rotating motor to work, the rotating motor drives the driving wheel to rotate, the driving wheel drives the driven wheel to rotate, and the driven wheel drives the smoke shield baffle to rotate in the horizontal flue, changing the angle between the smoke shield baffle and the flue gas flow direction to adjust the convective heat exchange between the last stage reheater and the high-temperature flue gas, and then adjust the outlet temperature of the last stage reheater, reduce the spraying amount of the accident cooling water of the last stage reheater, and improve the economy of the boiler.

[0016] The present invention has the following beneficial effects:

[0017] During specific operation of the device for regulating the temperature of the final stage reheater and the operating method thereof described in the present invention, when the final stage reheater is seriously slagging, the hydraulic cylinder pushes the hydraulic cylinder piston rod to extend, and drops the smoke shielding baffle to the front windward side of the final stage reheater, so as to block the high-temperature flue gas by the smoke shielding baffle, reduce the convective heat exchange between the final stage reheater and the high-temperature flue gas, and prevent the fly ash particles and molten alkali metals in the flue gas from adhering to the heating surface tube wall of the final stage reheater, thereby reducing the contamination and slagging of the heating surface of the final stage reheater, and effectively alleviate the contamination and slagging phenomenon of the heating surface of the final stage reheater when the boiler is operated at a high load for a long time. In addition, when the steam temperature deviation on both sides of the last stage reheater is too large, the smoke shield baffle is driven to rotate in the horizontal flue by a rotating motor to change the angle between the smoke shield baffle and the flue gas flow direction, so as to adjust the convective heat exchange between the last stage reheater and the high-temperature flue gas, and then adjust the outlet temperature of the last stage reheater, reduce the spray volume of the accident cooling water of the last stage reheater, improve the economy of the boiler, and at the same time reduce the smoke temperature deviation and uneven flow field on both sides of the furnace, avoid the frequent tube burst caused by local metal overheating and overheating of the last stage reheater, and improve the safety and reliability of unit operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a setting position diagram of the present invention;

[0019] Figure 2 It is a structural schematic diagram of the present invention;

[0020] Figure 3 It is a schematic diagram of the operation of the present invention.

[0021] Among them, 1 is an economizer, 2 is a furnace water-cooled wall, 3 is a low-temperature superheater, 4 is a screen superheater, 5 is a high-temperature superheater, 6 is a low-temperature reheater, 7 is a final reheater, 81 is a power box, 82 is a rotating motor, 83 is a driving wheel, 84 is a driven wheel, 85 is a hydraulic cylinder, 86 is a hydraulic cylinder piston rod, 87 is an ear seat, and 88 is a smoke shield. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0023] refer to Figure 1 and Figure 2 , Figure 1 A in the middle represents the present invention. The device for adjusting the temperature of the final reheater described in the present invention includes a controller, a rotating motor 82, a driving wheel 83, a driven wheel 84, a hydraulic cylinder 85, a hydraulic cylinder piston rod 86, a smoke shielding baffle 88 and a power supply box 81 for providing electric energy, wherein the smoke shielding baffle 88 is located between the high-temperature superheater 5 and the final reheater 7 in the horizontal flue of the boiler, the output shaft of the rotating motor 82 is connected to the driving wheel 83, the driving wheel 83 cooperates with the driven wheel 84, the driven wheel 84 is connected to the upper end of the smoke shielding baffle 88, one end of the hydraulic cylinder piston rod 86 cooperates with the hydraulic cylinder 85, and the other end of the hydraulic cylinder piston rod 86 is inserted into the horizontal flue of the boiler and connected to the smoke shielding baffle 88, and the controller is connected to the control end of the piston cylinder 85 and the control end of the rotating motor 82.

[0024] The output shaft of the rotating motor 82 is connected to the driving wheel 83 through the first connecting rod; the driven wheel 84 is connected to the upper end of the smoke shielding baffle 88 through the second connecting rod; the smoke shielding baffle 88 and the connection position between the hydraulic cylinder piston rod 86 and the boiler horizontal flue are wrapped with a layer of thermal insulation material; the driving wheel 83 and the driven wheel 84 are matched with each other through threads; the end of the hydraulic cylinder piston rod 86 is provided with an ear seat 87, and the ear seat 87 is connected to the upper end of the smoke shielding baffle 88; the rotating motor 82 is fixed to the outer wall of the boiler horizontal flue through the power box 81.

[0025] The operating method of the device for adjusting the temperature of the final reheater of the present invention comprises the following steps:

[0026] The high-temperature flue gas generated after the fuel is burned first transfers heat to the furnace water-cooled wall 2 and the platen superheater 4, and then enters the vertical shaft flue after passing through the high-temperature superheater 5 and the final reheater 7 in the horizontal flue. The partition wall in the vertical shaft flue divides the flue into two parallel flues, the front flue and the rear flue. The low-temperature reheater 6 is arranged in the front flue, and the low-temperature superheater 3 and the economizer 1 are arranged in the rear flue. The smoke shielding baffle 8 in the present invention is located between the high-temperature superheater 5 and the final reheater 7 in the horizontal flue.

[0027] During the normal operation of the boiler, if there is no over-temperature phenomenon on the tube wall of the final stage reheater 7, the outlet steam temperature deviation of the final stage reheater 7 is within the design range, and there is no serious contamination and slagging on the heating surface of the final stage reheater 7, the temperature adjustment device of the final stage reheater does not need to be put into use;

[0028] When the boiler is operated at a high load for a long time, since the average heat load in the furnace is greater than the preset heat load value, when the final reheater 7 is seriously slagging, the hydraulic cylinder 85 is controlled to work, and the hydraulic cylinder 85 drives the hydraulic cylinder piston rod 86 to extend, and the hydraulic cylinder piston rod 86 drives the smoke shielding baffle 88 to fall to the front windward side of the final reheater 7, and the high-temperature flue gas is shielded by the smoke shielding baffle 88, so as to reduce the convection heat exchange between the final reheater 7 and the high-temperature flue gas, and prevent the fly ash particles and molten alkali metals in the flue gas from adhering to the heating surface of the final reheater 7. The contamination and slagging of the heating surface of the final reheater 7 is reduced; when the tube wall of the final reheater 7 is over-temperature, the over-temperature phenomenon of the tube wall is alleviated by the opening of the smoke shielding baffle 88;

[0029] When the boiler is in variable load or deep peak regulation operation, the flame fullness in the furnace is not high. Due to the uneven distribution of heat load, the final reheaters 7 on both sides are prone to thermal deviation and unbalanced thermal stress. Long-term thermal deviation can easily cause the wall of the heating surface to crack, and in severe cases, it can cause local metal overheating and even tube bursting. When the steam temperature deviation on both sides of the final stage reheater 7 is too large, the hydraulic cylinder 85 is controlled to work, and the hydraulic cylinder 85 drives the hydraulic cylinder piston rod 86 to extend, and the hydraulic cylinder piston rod 86 drives the smoke shielding baffle 88 to fall to the front windward side of the final stage reheater 7, and then the rotating motor 82 is controlled to work, and the rotating motor 82 drives the driving wheel 83 to rotate, and the driving wheel 83 drives the driven wheel 84 to rotate, and the driven wheel 84 drives the smoke shielding baffle 88 to rotate in the horizontal flue, so as to change the angle between the smoke shielding baffle 88 and the flue gas flow direction, so as to adjust the convective heat exchange between the final stage reheater 7 and the high-temperature flue gas, and then adjust the outlet temperature of the final stage reheater 7, reduce the spraying amount of the accident cooling water of the final stage reheater 7, and improve the economy of the boiler.

[0030] Through practice, the present invention can effectively keep the heating surface clean, and at the same time can reduce the heat exchange amount of the heating surface, ensure the safety of the heating surface, increase the safe and stable operation time of the boiler, and improve the efficiency of the unit.

Claims

1. An operating method of a device for regulating the temperature of a final reheater, characterized in that: The device for regulating the temperature of the final reheater comprises a controller, a rotating motor (82), a driving wheel (83), a driven wheel (84), a hydraulic cylinder (85), a hydraulic cylinder piston rod (86), a smoke shielding baffle (88) and a power supply box (81) for providing electric energy, wherein the smoke shielding baffle (88) is located between the high-temperature superheater (5) and the final reheater (7) in the horizontal flue of the boiler, the output shaft of the rotating motor (82) is connected to the driving wheel (83), the driving wheel (83) is matched with the driven wheel (84), the driven wheel (84) is connected to the upper end of the smoke shielding baffle (88), one end of the hydraulic cylinder piston rod (86) is matched with the hydraulic cylinder (85), the other end of the hydraulic cylinder piston rod (86) is inserted into the horizontal flue of the boiler and connected to the smoke shielding baffle (88), and the controller is connected to the control end of the piston cylinder (85) and the control end of the rotating motor (82); The following steps are involved: When the final stage reheater (7) is seriously slagging, the controller controls the hydraulic cylinder (85) to work, the hydraulic cylinder (85) drives the hydraulic cylinder piston rod (86) to extend, and the hydraulic cylinder piston rod (86) drives the smoke shielding baffle (88) to fall to the front windward side of the final stage reheater (7), and the smoke shielding baffle (88) shields the high-temperature flue gas, thereby reducing the convection heat exchange between the final stage reheater (7) and the high-temperature flue gas, and preventing the fly ash particles and molten alkali metals in the flue gas from adhering to the heating surface tube wall of the final stage reheater (7), thereby reducing the contamination and slagging of the heating surface of the final stage reheater (7); When the steam temperature deviation on both sides of the final reheater (7) is greater than a preset value, the controller controls the hydraulic cylinder (85) to work, the hydraulic cylinder (85) drives the hydraulic cylinder piston rod (86) to extend, the hydraulic cylinder piston rod (86) drives the smoke shielding baffle (88) to fall to the front windward side of the final reheater (7), and then controls the rotary motor (82) to work, the rotary motor (82) drives the driving wheel (83) to rotate, the driving wheel (83) drives the driven wheel (84) to rotate, the driven wheel (84) drives the smoke shielding baffle (88) to rotate in the horizontal flue, and changes the angle between the smoke shielding baffle (88) and the flue gas flow direction, so as to adjust the convective heat exchange between the final reheater (7) and the high-temperature flue gas, and then adjust the outlet temperature of the final reheater (7), reduce the spraying amount of accident cooling water of the final reheater (7), and improve the economic efficiency of the boiler.

2. The operating method of the device for adjusting the temperature of the final reheater according to claim 1, characterized in that: The output shaft of the rotary motor (82) is connected to the driving wheel (83) via a first connecting rod.

3. The operating method of the device for adjusting the temperature of the final reheater according to claim 2, characterized in that: The driven wheel (84) is connected to the upper end of the smoke shielding baffle (88) via a second connecting rod.

4. The operating method of the device for adjusting the temperature of the final reheater according to claim 1, characterized in that: The smoke shielding baffle (88) and the connection position between the hydraulic cylinder piston rod (86) and the horizontal flue of the boiler are all wrapped with a heat-insulating material layer.

5. The operating method of the device for adjusting the temperature of the final reheater according to claim 1, characterized in that: The driving wheel (83) and the driven wheel (84) are matched with each other through threads.

6. The operating method of the device for regulating the temperature of the final reheater according to claim 1, characterized in that: An ear seat (87) is provided at the end of the hydraulic cylinder piston rod (86), and the ear seat (87) is connected to the upper end of the smoke shielding baffle (88).

7. The operating method of the device for regulating the temperature of the final reheater according to claim 1, characterized in that: The rotating motor (82) is fixed to the outer wall of the horizontal flue of the boiler through the power supply box (81).

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