CN111810926A - A device for adjusting the temperature of a final stage reheater and its operation method - Google Patents

Abstract

The invention discloses a device for adjusting the temperature of a final-stage reheater and an operation method thereof, comprising a controller, a rotating motor, a driving wheel, a driven wheel, a hydraulic cylinder, a piston rod of the hydraulic cylinder, a smoke shielding baffle, and a device for supplying electric energy. The power box of the power supply box, in which 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 with the driving wheel, the driving wheel is matched with the driven wheel, and the driven wheel is connected with the shielding wheel. The upper end of the smoke baffle is connected, one end of the piston rod of the hydraulic cylinder is matched with the hydraulic cylinder, the other end of the piston rod of the hydraulic cylinder is inserted into the horizontal flue of the boiler and connected to the smoke shielding baffle, and the controller is connected to the control end of the piston cylinder. The device and its operation method can effectively alleviate the contamination and slagging phenomenon of the heating surface of the final stage reheater under the long-term high-load operation state of the boiler, and improve the safety and reliability of the unit operation.

Description

A device for adjusting the temperature of a final stage reheater and its operation method

technical field

The invention belongs to the technical field of temperature regulation of the heating surface of a coal-fired boiler, and relates to a device for regulating the temperature of a final stage reheater and an operation method thereof.

Background technique

In recent years, the power industry has developed rapidly, and supercritical and ultra-supercritical thermal power units have become the main units in active service in my country. With the development of high-parameter and large-capacity power plant boilers, the problems of steam temperature deviation and heating surface overtemperature caused by unbalanced combustion in the furnace have become increasingly serious, which has become one of the main problems affecting the safe and stable operation of the unit. At the same time, due to the changes in the power consumption structure, the civil power consumption is increasing, and the peak-to-valley difference of the power grid is increasing. Negative Effects.

The uneven distribution of flue gas flow rate and flue temperature in the heating surface area of the boiler will lead to uneven heat absorption of the heating surfaces such as the screen superheater, high temperature superheater, and final reheater, and excessive steam temperature will accelerate the creep of the metal material of the heat exchanger. , causing extra thermal stress on the tube wall of the superheater and reheater, shortening the service life of the equipment, and long-term operation will cause the heating surface to overheat or even burst the tube; if the steam temperature is too low, the humidity of the steam in the final stage of the steam turbine will increase, and the steam turbine blades will be eroded. In addition, the drop in steam temperature affects the power generation efficiency of the steam turbine, and the coal consumption of the power generation unit increases. 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 desuperheating water cannot be reasonably controlled, resulting in a decline in the overall operating economy of the unit.

The methods of steam temperature adjustment are mainly divided into two categories: steam side adjustment and flue gas side adjustment. For the adjustment method of the steam temperature of the final reheater, the flue gas side adjustment is usually the main method. The common methods include flue gas recirculation, Separate the flue baffle and change the position of the center of the flame. At the same time, a reheater accident water spray desuperheater is also provided for emergency conditions, rapid load changes or other unstable conditions. The above adjustment methods all have different degrees of problems in the current operation of the unit: if the time lag of the steam temperature adjustment is too large by using the baffle method of separating the flue, the baffle opening has a nonlinear relationship with the air temperature, and the baffle only has a certain opening. It has a good adjustment effect within the range; the adjustment method of changing the flame center has high sensitivity and small time lag, but the accuracy is not high.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art, and to provide a device for adjusting the temperature of the final stage reheater and an operating method thereof, which can effectively alleviate the long-term high-load operation of the boiler under the condition of long-term high-load operation. The heating surface of the heater is contaminated with slagging, which improves the safety and reliability of the unit operation.

In order to achieve the above purpose, the device for adjusting the temperature of the final stage reheater according to the present invention includes a controller, a rotating motor, a driving wheel, a driven wheel, a hydraulic cylinder, a piston rod of a hydraulic cylinder, a smoke shielding baffle, and a device for providing electrical energy. The power box, 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 with the driving wheel, the driving wheel is matched with the driven wheel, and the driven wheel is connected with the smoke shielding The upper end of the baffle is connected, one end of the piston rod of the hydraulic cylinder is matched with the hydraulic cylinder, and the other end of the piston rod of the hydraulic cylinder is inserted into the horizontal flue of the boiler and connected to the smoke shielding baffle. The control terminal of the rotating motor is connected.

The output shaft of the rotary electric machine is connected with the driving wheel through the first connecting rod.

The driven wheel is connected with the upper end of the smoke shielding baffle through the second connecting rod.

The smoke shielding baffle plate and the connecting position of the piston rod of the hydraulic cylinder and the horizontal flue of the boiler are wrapped with a layer of thermal insulation material.

The driving wheel and the driven wheel are matched by threads.

The end of the piston rod of the hydraulic cylinder is provided with an ear seat, and the ear seat is connected with the upper end of the smoke shielding baffle.

The rotating motor is fixed on the outer wall of the horizontal flue of the boiler through the power box.

The operating method of the device for adjusting the temperature of the final stage reheater according to the present invention comprises the following steps:

When the slagging of the final reheater is serious, the controller controls the hydraulic cylinder to work, the hydraulic cylinder drives the piston rod of the hydraulic cylinder to extend, and the piston rod of the hydraulic cylinder drives the smoke shielding baffle to fall to the front windward side of the final reheater. The smoke shielding baffle shields the high temperature flue gas, reduces the convection heat exchange between the final 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 reheater , to reduce the contamination and slagging of the heating surface of the final reheater;

When the steam temperature deviation on both sides of the final 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 shielding baffle to fall to the final stage reheating The front windward side of the device, and then control 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 shielding baffle to rotate in the horizontal flue, changing the direction of the smoke shielding baffle and the flow of smoke. In order 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 amount of water sprayed by the accidental desuperheating water of the last-stage reheater, and improve the boiler economy. sex.

The present invention has the following beneficial effects:

During the specific operation of the device for adjusting the temperature of the final stage reheater and the operation method thereof, when the slagging of the final stage reheater is serious, the hydraulic cylinder pushes the piston rod of the hydraulic cylinder to extend, and the smoke shielding baffle falls down. To the front windward side of the last stage reheater, the high temperature flue gas is blocked by the smoke shielding baffle, which reduces the convection heat exchange between the last stage reheater and the high temperature flue gas, and prevents the adhesion of fly ash particles and molten alkali metals in the flue gas. At the tube wall of the heating surface of the last stage reheater, the fouling and slagging of the heating surface of the last stage reheater is reduced, and the phenomenon of fouling and slagging on the heating surface of the last stage reheater under the long-term high-load operation of the boiler is effectively alleviated. In addition, when the steam temperature deviation on both sides of the final stage reheater is too large, the rotating motor drives the smoke shielding baffle to rotate in the horizontal flue to change the angle between the smoke shielding baffle and the inflow direction of the flue gas to adjust the final stage. The convective heat exchange between the reheater and the high temperature flue gas, and then adjust the outlet temperature of the last stage reheater, reduce the amount of water sprayed by the accident desuperheating water of the last stage reheater, improve the boiler economy, and reduce the temperature on both sides of the furnace. The flue gas temperature deviation and the uneven flow field can avoid the frequent occurrence of pipe bursts caused by the overheating and overtemperature of the metal in the final stage reheater, and improve the safety and reliability of the unit operation.

Description of drawings

Fig. 1 is the setting position diagram of the present invention;

Fig. 2 is the structural representation of the present invention;

FIG. 3 is a schematic diagram of the operation of the present invention.

Among them, 1 is the economizer, 2 is the furnace water wall, 3 is the low temperature superheater, 4 is the screen superheater, 5 is the high temperature superheater, 6 is the low temperature reheater, 7 is the final stage reheater, and 81 is the 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 shielding baffle.

Detailed ways

Below in conjunction with accompanying drawing, the present invention is described in further detail:

Referring to FIG. 1 and FIG. 2, A in FIG. 1 is the present invention, and the device for adjusting the temperature of the final stage reheater according to the present invention includes a controller, a rotary motor 82, a driving wheel 83, a driven wheel 84, a hydraulic cylinder 85, a hydraulic pressure The cylinder piston rod 86, the smoke shielding baffle 88 and the power supply box 81 for supplying electrical energy, wherein the smoke shielding baffle 88 is located between the high temperature superheater 5 and the final stage reheater 7 in the horizontal flue of the boiler, and the rotating motor 82 The output shaft is connected with the driving wheel 83, the driving wheel 83 is matched with the driven wheel 84, the driven wheel 84 is connected with 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, and the hydraulic cylinder piston The other end of the 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 rotary motor 82 .

The output shaft of the rotary motor 82 is connected with the driving wheel 83 through the first connecting rod; the driven wheel 84 is connected with the upper end of the smoke shielding baffle 88 through the second connecting rod; the smoke shielding baffle 88 and the hydraulic cylinder piston rod 86 are connected to the The connection positions of the horizontal flue of the boiler are all wrapped with a layer of thermal insulation material; the driving wheel 83 and the driven wheel 84 are matched by 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 smoke shield. The upper ends of the plates 88 are connected; the rotary motor 82 is fixed on the outer wall of the horizontal flue of the boiler through the power box 81 .

The operating method of the device for adjusting the temperature of the final stage reheater according to the present invention comprises the following steps:

The high-temperature flue gas generated after the fuel is burned first transfers heat to the furnace water wall 2 and the screen superheater 4, and then the horizontal flue passes through the high-temperature superheater 5 and the final reheater 7 in turn, and then enters the vertical shaft flue. The partition wall in the flue divides the flue into two parallel flues, front and rear. 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 in the present invention 8 is located between the high temperature superheater 5 and the final stage reheater 7 in the horizontal flue;

During the normal operation of the boiler, there is no over-temperature phenomenon on the tube wall of the last stage reheater 7, the temperature deviation of the steam at the outlet of the last stage reheater 7 is within the design range, and the heating surface of the last stage reheater 7 is not seriously polluted and slagging. The device for temperature adjustment of the final reheater does not need to be put into use;

When the boiler runs at high load for a long time, due to the large average heat load in the furnace and the preset heat load value, when the slagging of the final stage reheater 7 is serious, the hydraulic cylinder 85 is controlled to work, and the hydraulic cylinder 85 drives the hydraulic cylinder piston rod 86 Extend, the hydraulic cylinder piston rod 86 drives the smoke shielding baffle 88 to drop to the front windward side of the last stage reheater 7, and the high temperature flue gas is shielded by the smoke shielding baffle 88, reducing the distance between the last stage reheater 7 and the high temperature flue gas. Convective heat exchange prevents fly ash particles and molten alkali metals in the flue gas from adhering to the tube wall of the heating surface of the final stage reheater 7, reducing the contamination and slagging of the heating surface of the final stage reheater 7; When the tube wall of the reheater 7 is overheated, the opening of the smoke shielding baffle 88 is used to alleviate the overtemperature phenomenon of the tube wall;

When the boiler is in variable load or deep peak shaving operation, the fullness of the flame in the furnace is not high. Due to the uneven distribution of heat load, the last stage reheaters 7 on both sides are prone to problems such as thermal deviation and thermal stress imbalance, and long-term thermal deviation is easy to occur. The pipe wall of the heating surface will be cracked, and in severe cases, the local metal will be overheated and overheated, and even the pipe will burst. 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, 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 drop to the final stage On the front windward side of the reheater 7, the rotary motor 82 is controlled to work, the rotary motor 82 drives the driving wheel 83 to rotate, 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, Change the angle between the smoke shielding baffle 88 and the direction of the flow of the flue gas to adjust the convection 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 to reduce the final stage reheater 7. The amount of water sprayed by the reheater 7 accident desuperheating water improves the boiler economy.

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

Claims (8)

1. A temperature adjusting device of a final-stage reheater is characterized by comprising 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 plate (88) and a power box (81) for providing electric energy, the smoke shielding baffle (88) is positioned between the high-temperature superheater (5) and the final-stage reheater (7) in the horizontal flue of the boiler, an output shaft of the rotating motor (82) is connected with the driving wheel (83), the driving wheel (83) is matched with the driven wheel (84), the driven wheel (84) is connected with the upper end of the smoke shielding baffle (88), one end of a 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 then is connected with the smoke shielding baffle (88), and the controller is connected with the control end of the piston cylinder (85) and the control end of the rotating motor (82).

2. The final reheater temperature regulating apparatus according to claim 1, characterized in that the output shaft of the rotary electric machine (82) is connected to the drive wheel (83) by a first link.

3. The final reheater temperature conditioning apparatus of claim 2 wherein the driven pulley (84) is connected to the upper end of the smoke barrier (88) by a second link.

4. The final reheater temperature conditioning apparatus of claim 1 wherein the smoke barrier (88) and the connection between the hydraulic cylinder piston rod (86) and the boiler horizontal flue are coated with a layer of insulation material.

5. The final reheater temperature conditioning apparatus of claim 1 wherein the drive pulley (83) is threadably engaged with the driven pulley (84).

6. The final reheater temperature regulating apparatus according to claim 1, characterized in that the end of the hydraulic cylinder piston rod (86) is provided with a lug (87), and the lug (87) is connected to the upper end of a smoke baffle (88).

7. The apparatus for temperature regulation of a final stage reheater according to claim 1, wherein the rotary electric machine (82) is fixed to an outer wall of the horizontal flue of the boiler through a power supply box (81).

8. A method of operating a final reheater temperature conditioning apparatus as recited in claim 1, comprising the steps of:

when the slag bonding of the final-stage reheater (7) is serious, the controller controls the hydraulic cylinder (85) to work, the hydraulic cylinder (85) drives a hydraulic cylinder piston rod (86) to extend out, the hydraulic cylinder piston rod (86) drives a smoke shielding baffle (88) to fall to the front windward side of the final-stage reheater (7), high-temperature flue gas is shielded through the smoke shielding baffle (88), the convection heat exchange between the final-stage reheater (7) and the high-temperature flue gas is reduced, fly ash particles and molten alkali metal in the flue gas are prevented from being attached to the pipe wall of the heating surface of the final-stage reheater (7), and the slag bonding of the heating surface of the final-stage reheater (7);

when the steam temperature deviation of two sides of the final-stage reheater (7) is larger than a preset value, the controller controls the hydraulic cylinder (85) to work, the hydraulic cylinder (85) drives a piston rod (86) of the hydraulic cylinder to extend out, the piston rod (86) of the hydraulic cylinder drives the smoke shielding baffle (88) to fall to the front windward side of the final-stage reheater (7), then the rotary motor (82) is controlled to work, the rotary motor (82) drives a driving wheel (83) to rotate, the driving wheel (83) drives a driven wheel (84) to rotate, the driven wheel (84) drives the smoke shielding baffle (88) to rotate in a horizontal flue, the included angle between the smoke shielding baffle (88) and the incoming flow direction of flue gas is changed, so that the heat convection heat exchange quantity between the final-stage reheater (7) and high-temperature flue gas is adjusted, the outlet temperature of the final-stage reheater (7) is adjusted.

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