CN111306568A - Device and method for relieving blockage of rotary air preheater by preheating heat storage element through hot air - Google Patents

Abstract

The invention discloses a device and method for relieving the clogging of a rotary air preheater by a hot-air preheating heat storage element. The fan-shaped plate at the cold end of the preheating bin and the outlet pipe for the preheating cold air, etc. An independent heat storage element preheating chamber is formed between the fan-shaped plate at the hot end of the preheating chamber and the fan-shaped plate at the cold end of the preheating chamber. Before the gas separation bin, use the hot primary air to preheat the heat storage element from top to bottom, increase the temperature of the heat storage element when it enters the flue gas separation bin, so as to achieve the purpose of reducing the deposition area of ammonium hydrogen sulfate (abbreviated as ABS) and make it more efficient. It is easy to be removed by the soot blower, which solves the serious problem of air preheater blockage caused by ABS adhesion in the rotary air preheater of coal-fired power plant boilers.

Description

Device and method for relieving clogging of rotary air preheater with hot-air preheating heat storage element

technical field

The invention relates to a device and a method for alleviating clogging of a rotary air preheater, belonging to the field of preventing and controlling the clogging of a rotary air preheater.

Background technique

Selective Catalytic Reduction (SCR) is a denitrification technology widely used in thermal power plants. Its technical principle is to inject ammonia (NH ₃ ) into the flue gas. _3. Reduction and removal reaction occurs preferentially with nitrogen oxides (NOx) in the flue gas to generate nitrogen and water. In addition to the above main reaction, it will also be accompanied by a small amount of sulfur dioxide (SO ₂ ) oxidation to sulfur trioxide (SO ₃ ), and then Ammonium hydrogen sulfate (NH ₄ HSO ₄ , also known as ABS) is generated under certain reaction conditions with ammonia that is not completely reacted with SCR denitration process. ABS has strong viscosity in liquid state, and ABS will condense in the flue gas under the temperature window of 146℃～220℃.

Rotary air preheater (referred to as "rotary air preheater" or "air preheater") is an important heat exchange rotating equipment for coal-fired units. , heat the low-temperature air entering the furnace, the temperature range of the flue gas flowing through the rotary air preheater is 110℃~400℃, and the metal wall temperature of the heat exchange element is generally 80℃~380℃, which crosses the ABS condensation Therefore, when there is ABS in the flue gas, the ABS is easy to condense and deposit on the surface of the air preheater heat storage element, and the strong viscosity is also easy to adhere to the fly ash in the flue gas, thus causing the air preheater to enter the air. The outlet pressure difference gradually increases, and the blockage gradually increases.

At the same time, in recent years, due to the implementation of the ultra-clean emission transformation project and the reduction of the unit load rate, the problem of ABS blockage and corrosion in the air preheater of coal-fired thermal power plants has become more and more prominent, and the air preheater in some power plants is blocked due to ABS. As high as 3000~4000Pa, it will increase the power consumption of the fan, and the economy will decrease. In the worst case, it will affect the load capacity of the unit, and even the accident of the fan stall and shutdown occurs, which seriously affects the normal operation of the unit. Therefore, how to solve or alleviate the air preheater ABS clogging problem online is a technical problem that needs to be solved urgently.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the clogging of the rotary air preheater caused by ABS condensation deposited on the heat storage element and adhere to the fly ash, and to provide a kind of reasonable structure design, low construction cost, safe use, convenient adjustment and can play a good effect. device and method.

The technical scheme adopted by the present invention to solve the above problems is: a device for relieving the clogging of a rotary air preheater by a hot air preheating heat storage element, comprising a rotary air preheater, a cold primary air duct, a hot primary air duct, a cold primary air duct, and a cooling air preheater. Secondary air duct, hot secondary air duct, flue gas outlet duct and flue gas inlet duct, the flue gas inlet duct and flue gas outlet duct are respectively connected with the flue gas inlet and flue gas of the rotary air preheater. The outlet is connected, the cold primary air duct and the hot primary air duct are respectively connected with the primary air inlet and the primary air outlet of the rotary air preheater, and the cold secondary air duct and the hot secondary air duct are respectively connected with the rotary air preheater. The secondary air inlet and the secondary air outlet of the device are communicated with each other; it is characterized in that it also includes a hot primary air outlet pipe and a preheated cold air outlet pipe, and the inlet and outlet of the hot primary air outlet pipe are respectively connected with the hot primary air duct and the rotary type air preheater, the inlet and outlet of the preheating cold air outlet pipe are respectively connected with the rotary air preheater and the cold secondary air duct, and the rotary air preheater is provided with a primary air hot end fan plate, a primary air preheater Air-cooled end fan-shaped plate, secondary air hot-end fan-shaped plate, secondary air-cooled end fan-shaped plate, flue gas hot-end fan-shaped plate, flue gas cold-end fan-shaped plate, preheating chamber hot end fan-shaped plate and preheating chamber cold end fan-shaped plate The primary air heating end fan-shaped plate, the secondary air heating end fan-shaped plate, the flue gas hot-end fan-shaped plate, and the preheating bin hot-end fan-shaped plate are respectively connected with the primary air cooling end fan-shaped plate, the secondary air cooling end fan-shaped plate, the smoke The fan-shaped plates at the air cooling end and the fan-shaped plates at the cold end of the preheating chamber are arranged correspondingly, and the fan-shaped plates at the hot end of the preheating chamber and the fan-shaped plates at the cold end of the preheating chamber are formed between the fan-shaped plates at the hot end of the flue gas and the fan-shaped plates at the cold end of the flue gas. An independent preheating bin, the hot primary air drawing out pipe and the preheating cold air drawing out pipe are communicated with the preheating bin. The hot primary air is introduced into the preheating chamber to heat the heat storage element that is about to enter the flue gas chamber, and the wall temperature of the heat storage element is increased. Into the cold secondary air, the power of the whole process flow is provided by the pressure difference between the hot primary air and the cold secondary air. Except for a small increase in the output of the primary fan, there is no other additional energy consumption.

Further, when the rotation direction of the rotary air preheater is flue gas-primary air-secondary air, the preheating bin is located between the flue gas sub-silo and the secondary air sub-silo; When the rotation direction is flue gas-secondary air-primary air, the preheating bin is located between the flue gas sub-silo and the primary air sub-silo.

Further, the angle of the preheating bin is θ, 0°≤θ≤20°.

Further, a hot-end shut-off damper and an adjustment damper are installed on the hot primary air extraction pipe, which are used to control the switch of the device and adjust the volume of the primary air. The cold-end shut-off damper is installed on the preheated cold air outlet pipe to reduce secondary air leakage when the device is closed.

Preferably, the shut-off damper and the regulating damper provided on the hot primary air extraction duct and the preheated cold air extraction duct are operated remotely by electric or pneumatic actuators.

The working method of the device for relieving the blockage of the rotary air preheater by using the hot primary air to preheat the heat storage element is characterized in that the heat storage element is preheated by the hot primary air from the hot end to the cold end of the preheating chamber, so as to improve the storage capacity. The temperature of the heating element when it enters the flue gas sub-silo, so that the deposition area of ammonium hydrogen sulfate (abbreviated as ABS) moves down, avoids cross-layer accumulation, and is easier to be effectively cleaned by soot blowing, so as to relieve the clogging of the rotary air preheater.

Compared with the prior art, the invention has the following advantages and effects: using the hot primary air to preheat the rotary air preheater heat storage element that is about to enter the flue gas sub-silo, so that the ABS deposition area is moved down, and the original deposition area is higher, The soot blower cannot be covered or the soot blowing effect is poor. After the deposition area moves down, the soot blowing effect will be improved and the degree of clogging will be reduced. At the same time, the preheating cold air and the cold secondary air will increase the temperature of the secondary air entering the air preheater, and will also increase the wall temperature of the heat storage element, enhancing the effect of relieving blockage. In addition, the power for the flow of the whole process of the device is provided by the pressure difference between the hot primary air and the cold secondary air. Except for a small increase in the output of the primary fan, there is no other additional energy consumption. The pipeline can be flexibly arranged according to the site conditions, which is convenient for installation and construction.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the present invention;

2 is a plan view of the arrangement of the fan-shaped plates of the three-silo air preheater in the embodiment of the present invention;

FIG. 3 is a schematic diagram of a work flow in an embodiment of the present invention.

In the figure: Rotary air preheater 1, central truss 2, primary air heating end fan plate 3, primary air cooling end fan plate 3-1, secondary air heating end fan plate 4, secondary air cooling end fan plate 4- 1. Flue gas hot end fan plate 5, flue gas cold end fan plate 5-1, preheating chamber hot end fan plate 6, preheating chamber cold end fan plate 6-1, cold primary air duct 7, hot primary air duct 8. Cold secondary air duct 9, hot secondary air duct 10, flue gas outlet duct 11, flue gas inlet duct 12, hot primary air outlet duct 13, preheated cold air outlet duct 14, hot end shut-off damper 15 , Adjust the damper 16 , the cold end shut-off damper 17 , and the preheating bin 18 .

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and through the examples. The following examples are to explain the present invention and the present invention is not limited to the following examples.

Referring to FIGS. 1 to 3 , in this embodiment, a device for relieving clogging of a rotary air preheater with a hot-air preheating heat storage element includes a rotary air preheater 1 , a cold primary air duct 7 , and a hot primary air duct 8. The cold secondary air duct 9, the hot secondary air duct 10, the flue gas outlet duct 11 and the flue gas inlet duct 12, the flue gas inlet duct 12 and the flue gas outlet duct 11 are respectively connected with the rotary air preheater. The flue gas inlet and the flue gas outlet of The air duct 10 is communicated with the secondary air inlet and the secondary air outlet of the rotary air preheater 1 respectively; it also includes a hot primary air outlet duct 13 and a preheated cold air outlet duct 14, and the inlet and outlet of the hot primary air outlet duct 13 are respectively It is communicated with the hot primary air duct 8 and the rotary air preheater 1, and the inlet and outlet of the preheating cold air outlet duct 14 are respectively communicated with the rotary air preheater 1 and the cold secondary air duct 9. The rotary air preheater 1 is provided with There are primary air heating end fan-shaped plate 3, primary air cooling end fan-shaped plate 3-1, secondary air heating end fan-shaped plate 4, secondary air cooling end fan-shaped plate 4-1, flue gas hot end fan-shaped plate 5, flue gas cooling The end fan-shaped plate 5-1, the hot-end fan-shaped plate 6 of the preheating chamber and the cold-end fan-shaped plate 6-1 of the preheating chamber, and the primary air hot end fan-shaped plate 3, the secondary air hot end fan-shaped plate 4, the flue gas hot end fan-shaped plate Plate 5, the fan-shaped plate 6 at the hot end of the preheating chamber are respectively connected with the fan-shaped plate at the primary air cooling end 3-1, the fan-shaped plate at the secondary air cooling end 4-1, the fan-shaped plate at the cold end of the flue gas 5-1, and the fan-shaped plate at the cold end of the preheating chamber. The plates 6-1 are arranged correspondingly, and the preheating chamber hot end fan-shaped plate 6 and the preheating chamber cold end fan-shaped plate 6-1, the flue gas hot end fan-shaped plate 5 and the flue gas cold end fan-shaped plate 5-1 form an independent The preheating chamber 18 , the hot primary air outlet duct 13 and the preheated cold air outlet duct 14 are communicated with the preheating chamber 18 . The hot primary air is introduced into the preheating chamber 18 to heat the heat storage element that is about to enter the flue gas chamber, and the wall temperature of the heat storage element is increased. Then it enters into the cold secondary air. The power of the whole process is provided by the pressure difference between the hot primary air and the cold secondary air. Except for a small increase in the output of the primary fan, there is no other additional energy consumption.

In this embodiment, when the rotation direction of the rotary air preheater 1 is flue gas-primary air-secondary air, the preheating bin 18 is located between the flue gas sub-silo and the secondary air sub-silo; When the rotation direction of the device 1 is flue gas-secondary air-primary air, the preheating bin 18 is located between the flue gas sub-silo and the primary air sub-silo. The angle of the preheating chamber 18 is θ, and 0°≤θ≤20°.

In this embodiment, the hot-end shut-off damper 15 and the regulating damper 16 are installed on the hot primary air extraction duct 13, which are used to control the switch of the device and adjust the volume of the primary air. A cold end shut-off damper 17 is installed on the preheated cold air outlet duct 14 to reduce secondary air leakage when the device is closed.

In this embodiment, the shut-off damper and the regulating damper provided on the hot primary air outlet duct 13 and the preheated cold air outlet duct 14 are operated remotely by electric or pneumatic actuators.

The working method is to use the hot primary air to preheat the heat storage element from the hot end to the cold end of the preheating chamber 18 to increase the temperature of the heat storage element when it enters the flue gas sub-silo, so that the deposition area of ammonium hydrogen sulfate (abbreviated as ABS) is lowered. To avoid cross-layer accumulation, it is easier to be effectively cleaned by soot blowing, and the clogging of the rotary air preheater 1 is relieved.

Contents not described in detail in this specification belong to the prior art known to those skilled in the art.

Although the present invention has been disclosed as above with examples, it is not intended to limit the protection scope of the present invention. Any changes and modifications made by those skilled in the art without departing from the concept and scope of the present invention should be It belongs to the protection scope of the present invention.

Claims (5)

1. A device for relieving blockage of a rotary air preheater by a hot-air preheating heat storage element comprises a rotary air preheater (1), a primary cold air duct (7), a primary hot air duct (8), a secondary cold air duct (9), a secondary hot air duct (10), a smoke outlet air duct (11) and a smoke inlet air duct (12), wherein the smoke inlet air duct (12) and the smoke outlet air duct (11) are respectively communicated with a smoke inlet and a smoke outlet of the rotary air preheater (1), the primary cold air duct (7) and the primary hot air duct (8) are respectively communicated with a primary air inlet and a primary air outlet of the rotary air preheater (1), and the secondary cold air duct (9) and the secondary hot air duct (10) are respectively communicated with a secondary air inlet and a secondary air outlet of the rotary air preheater (1); the air preheater is characterized by further comprising a hot primary air leading-out pipeline (13) and a preheated cold air leading-out pipeline (14), wherein an inlet and an outlet of the hot primary air leading-out pipeline (13) are respectively communicated with a hot primary air channel (8) and a rotary air preheater (1), an inlet and an outlet of the preheated cold air leading-out pipeline (14) are respectively communicated with the rotary air preheater (1) and a cold secondary air channel (9), a primary air-heat end sector plate (3), a primary air-cold end sector plate (3-1), a secondary air-heat end sector plate (4), a secondary air-cold end sector plate (4-1), a flue gas hot end sector plate (5), a flue gas cold end sector plate (5-1), a preheated bin cold end sector plate (6) and a preheated bin cold end sector plate (6-1) are arranged on the rotary air preheater (1), and the primary air-heat end sector plate (3), the secondary air-heat end sector plate (4) and, The preheating bin is characterized in that a flue gas hot end sector plate (5) and a preheating bin hot end sector plate (6) are respectively and correspondingly arranged with a primary air cold end sector plate (3-1), a secondary air cold end sector plate (4-1), a flue gas cold end sector plate (5-1) and a preheating bin cold end sector plate (6-1), a preheating bin (18) is formed between the preheating bin hot end sector plate (6) and the preheating bin cold end sector plate (6-1) and between the flue gas hot end sector plate (5) and the flue gas cold end sector plate (5-1), and a hot primary air leading-out pipeline (13) and a preheating cold air leading-out pipeline (14) are communicated with the preheating bin (18).

2. The device for relieving the blockage of the rotary air preheater of claim 1, wherein when the rotary air preheater (1) rotates in the direction of flue gas-primary air-secondary air, the preheating bin (18) is located between the flue gas sub-bin and the secondary air sub-bin; when the rotation direction of the rotary air preheater (1) is flue gas-secondary air-primary air, the preheating bin (18) is positioned between the flue gas sub-bin and the primary air sub-bin.

3. The device for alleviating the blockage of the rotary air preheater of the hot-air preheating heat storage element as claimed in claim 1, wherein the angle of the preheating bin (18) is theta, and theta is more than or equal to 0 degrees and less than or equal to 20 degrees.

4. The device for relieving the blockage of the rotary air preheater of the hot-air preheating heat storage element according to claim 1, wherein a hot-end shutoff damper (15) and a regulating damper (16) are installed on the hot primary air outlet pipeline (13); and a cold end shutoff air door (17) is installed on the preheated cold air leading-out pipeline (14).

5. A working method of the device for relieving the blockage of the rotary air preheater by preheating the heat storage element by hot air according to any one of claims 1 to 4, which is characterized in that the heat storage element is preheated by hot primary air from the hot end to the cold end of the preheating bin (18), the temperature of the heat storage element entering the flue gas bin is increased, so that an ammonium bisulfate deposition area is moved downwards, cross-layer accumulation is avoided, the heat storage element is more easily and effectively cleaned by soot blowing, and the blockage of the rotary air preheater (1) is relieved.

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