Heat pipe type air preheater system

Abstract

The utility model discloses a heat pipe type air preheater system which comprises a main body and an air preheater, the main body is arranged at the bottom of the rotary air preheater, the main body is composed of a plurality of heat pipe heat exchanger modules which are vertically arranged and parallel to one another, and each heat pipe heat exchanger module comprises an air channel and a flue which are separated from each other. A heat pipe heat exchanger is assembled in each heat pipe heat exchanger module and stretches across the air channel and the flue, and a baffle is arranged at an air inlet in the bottom of the air channel of each heat pipe heat exchanger module. The heat pipe type air preheater is used for thoroughly solving the blockage problem of a rotary air preheater, the blockage and corrosion phenomena of the air preheater are effectively treated, and accidents such as negative pressure fluctuation of a boiler hearth, fan surging and the like which influence safe operation of the boiler are avoided.

Description

Technical Field

[0001] The utility model relates to a heat pipe type air preheater system, belonging to the technical field of heat exchange equipment. Background Art

[0002] As a necessary heat exchange equipment for large power station boilers, rotary air preheaters are common problems of low-temperature corrosion and ash blockage. With the improvement of environmental protection and peak load requirements, low-temperature corrosion and blockage problems are more serious. If the air preheater is blocked, the primary and secondary air pressure will increase, the negative pressure in the furnace will be difficult to maintain and periodic swing will occur. In severe cases, it will cause the fan to surge, affect combustion, increase the exhaust temperature, and the boiler cannot operate at full load.

[0003] SO3 in the flue gas reacts with water vapor to generate sulfuric acid vapor. When the wall temperature of the air preheater is lower than the flue gas dew point, sulfuric acid vapor will condense on the heating surface of the air preheater, corrode the metal of the heating surface and adhere to the ash in the flue gas, thus causing the air preheater to be blocked by ash. A small amount of ammonia escaping from the SCR denitrification system reacts with SO3 in the flue gas to generate ammonium bisulfate, which is gaseous above 220°C, solid below 146°C, and liquid between 146 and 220°C. Liquid ammonium bisulfate is a very viscous substance that easily adheres to the heating surface and captures fly ash in the flue gas to form scaling. The liquid temperature range of ammonium bisulfate is exactly in the air preheater, and the gap between the heat storage elements of the rotary air preheater is small, so ammonium bisulfate blockage is likely to occur.

[0004] At present, the mainstream solution to the blockage of air preheater is to control the ammonia escape and SO3 content in the flue gas, optimize the design of the air preheater heat storage element structure, increase the air inlet temperature, hot air recirculation, steam purge and other technical measures to alleviate the speed and degree of blockage, but it cannot completely solve the blockage problem of air preheater. Therefore, a heat pipe air preheater system is provided. Utility Model Content

[0005] The utility model aims to provide a heat pipe air preheater system, which utilizes the heat pipe air preheater to solve the clogging problem of the rotary air preheater and prevent the rotary air preheater from being clogging due to acid dew corrosion and ammonium bisulfate.

[0006] In order to solve the above technical problems, the utility model adopts the following technical solutions: a heat pipe air preheater system, comprising a main body and a rotary air preheater, wherein the main body is arranged at the bottom of the rotary air preheater, and the main body is composed of a plurality of heat pipe heat exchanger modules vertically set up and parallel to each other;

[0007] The heat pipe heat exchanger module includes an air duct and a flue separated from each other. A heat pipe heat exchanger is installed in each of the heat pipe heat exchanger modules. The heat pipe heat exchanger spans the air duct and the flue. The heat pipe heat exchanger includes an evaporation section and a condensation section. The evaporation section of the heat pipe heat exchanger is placed in the flue, and the condensation section of the heat pipe heat exchanger is placed in the air duct. The air inlet at the bottom of the air duct of each of the heat pipe heat exchanger modules is provided with an openable and closable baffle.

[0008] In the aforementioned heat pipe air preheater system, both ends of the air duct inlet and outlet of the heat pipe heat exchanger module are provided with air duct pressure transmitters and air duct temperature transmitters, and the air duct pressure transmitters and air duct temperature transmitters are located on the inner side of the baffle.

[0009] In the aforementioned heat pipe air preheater system, both ends of the flue inlet and outlet of the heat pipe heat exchanger module are provided with a flue pressure transmitter and a flue temperature transmitter.

[0010] In the aforementioned heat pipe air preheater system, both the evaporation section and the condensation section of the heat pipe heat exchanger are provided with fins.

[0011] In the aforementioned heat pipe air preheater system, the heat pipe heat exchanger adopts a gravity heat pipe, and the evaporation section of the heat pipe heat exchanger is lower than the condensation section and is arranged at a 5° inclination.

[0012] In the aforementioned heat pipe air preheater system, the baffle is electrically connected to an electric actuator.

[0013] In the aforementioned heat pipe air preheater system, the evaporating section of the heat pipe heat exchanger has metal wall temperature measuring points distributed in the transverse direction, and the number of the metal wall temperature measuring points is 3-5.

[0014] Compared with the prior art, the utility model utilizes a heat pipe air preheater to completely solve the blockage problem of the rotary air preheater, effectively controls the blockage and corrosion of the rotary air preheater, and avoids the occurrence of accidents that affect the safe operation of the boiler, such as fluctuations in the negative pressure of the boiler furnace and surging of the fan; the heat pipe heat exchanger has a simple structure, high heat exchange efficiency, and flexible heat pipe arrangement; the heat pipe is completely isolated from the flue gas and air, and even if it is damaged, it will not cause air leakage in the air preheater. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the utility model;

[0016] Figure 2 This is a schematic diagram of the structure of the heat pipe heat exchanger module on the air duct side of the utility model:

[0017] Figure 3 This is a schematic diagram of the structure of the heat pipe heat exchanger module on the flue side of the utility model;

[0018] Figure 4 It is a schematic diagram of the structure of the heat pipe heat exchanger of the utility model.

[0019] Figure numerals: 1-air preheater, 2-air duct, 3-flue duct, 4-rotary air preheater, 5-heat pipe heat exchanger, 6-heat pipe heat exchanger module, 7-baffle, 8-air duct pressure transmitter, 9-air duct temperature transmitter, 10-flue duct pressure transmitter, 11-flue duct temperature transmitter.

[0020] The utility model is further described below in conjunction with the accompanying drawings and specific implementation methods. DETAILED DESCRIPTION

[0021] Embodiment 1 of the present utility model: A heat pipe air preheater system comprises a main body 1 and a rotary air preheater 4, wherein the main body 1 is arranged at the bottom of the rotary air preheater 4, and the main body 1 is composed of a plurality of heat pipe heat exchanger modules 6 vertically arranged and parallel to each other;

[0022] The heat pipe heat exchanger module 6 includes an air duct 2 and a flue 3 separated from each other. A heat pipe heat exchanger 5 is installed in each heat pipe heat exchanger module 6. The heat pipe heat exchanger 5 spans the air duct 2 and the flue 3. The heat pipe heat exchanger 5 includes an evaporation section and a condensation section. The evaporation section of the heat pipe heat exchanger 5 is placed in the flue 3, and the condensation section of the heat pipe heat exchanger 5 is placed in the air duct 2. The heat pipe heat exchanger 5 increases the inlet temperature of the primary and secondary air of the rotary air preheater 4, reduces the heat exchange rate, and keeps the outlet flue gas temperature of the rotary air preheater 4 above 220°C, completely preventing the rotary air preheater 4 from acid dew corrosion blockage and ammonium bisulfate blockage. Each heat pipe heat exchanger module 6 is placed on the bottom air inlet on the side of the air duct 2. An openable and closable baffle 7 is provided, and the baffle 7 has only two states: fully open and fully closed. After the heat pipe heat exchanger 5 is clogged with dust, the air side baffles 7 of the corresponding heat pipe heat exchanger modules 6 are closed in turn. When the air baffles 7 are closed, the metal temperature of the heat pipes of the heat pipe heat exchanger modules 6 rises to above 220° C., the ammonium bisulfate is gasified, and the scale is quickly blown away by the flue gas, keeping the heating surface of the heat pipe heat exchanger 5 clean.

[0023] Embodiment 2 of the present utility model: A heat pipe air preheater system comprises a main body 1 and a rotary air preheater 4, wherein the main body 1 is arranged at the bottom of the rotary air preheater 4, and the main body 1 is composed of a plurality of heat pipe heat exchanger modules 6 vertically arranged and parallel to each other;

[0024] The heat pipe heat exchanger module 6 includes an air duct 2 and a flue 3 separated from each other. A heat pipe heat exchanger 5 is installed in each heat pipe heat exchanger module 6. The heat pipe heat exchanger 5 spans the air duct 2 and the flue 3. The heat pipe heat exchanger 5 includes an evaporation section and a condensation section. The evaporation section of the heat pipe heat exchanger 5 is placed in the flue 3, and the condensation section of the heat pipe heat exchanger 5 is placed in the air duct 2. The heat pipe heat exchanger 5 increases the inlet temperature of the primary and secondary air of the rotary air preheater 4, reduces the heat exchange capacity of the rotary air preheater 4, and keeps the outlet flue gas temperature of the rotary air preheater 4 above 220°C, completely preventing the rotary air preheater 4 from acid dew corrosion blockage and ammonium bisulfate blockage. Each heat pipe heat exchanger module 6 is placed on the bottom air inlet on the side of the air duct 2. An openable and closable baffle 7 is provided, and the baffle 7 has only two states: fully open and fully closed. After the heat pipe heat exchanger 5 is clogged with dust, the air side baffles 7 of the corresponding heat pipe heat exchanger modules 6 are closed in turn. When the air baffles 7 are closed, the metal temperature of the heat pipes of the heat pipe heat exchanger modules 6 rises to above 220° C., the ammonium bisulfate is gasified, and the scale is quickly blown away by the flue gas, keeping the heating surface of the heat pipe heat exchanger 5 clean.

[0025] Both ends of the inlet and outlet of the air duct 2 of the heat pipe heat exchanger module 6 are provided with an air duct pressure transmitter 8 and an air duct temperature transmitter 9, which are located on the inner side of the baffle 7 to measure the changes in the pressure and temperature of the primary air and secondary air of the preheater; both ends of the inlet and outlet of the flue 3 of the heat pipe heat exchanger module 6 are provided with a flue pressure transmitter 10 and a flue temperature transmitter 11 to measure the changes in the flue gas pressure and temperature; the evaporation section of the heat pipe heat exchanger 5 is horizontally distributed with metal wall temperature measuring points, and the number of the metal wall temperature measuring points is 3-5, which measure the metal temperature distribution of the heat pipe along the cross-section of the module and the changes in the metal wall temperature; according to the changes in the inlet and outlet pressure and temperature of the flue gas, it is judged whether the heat pipe heat exchanger 5 is blocked and the severity of the blockage, and according to the changes in the metal wall temperature of the heat pipes of each module, it is judged which heat pipe heat exchanger module 6 is blocked.

[0026] Embodiment 3 of the present utility model: A heat pipe air preheater system comprises a main body 1 and a rotary air preheater 4, wherein the main body 1 is arranged at the bottom of the rotary air preheater 4, and the main body 1 is composed of a plurality of heat pipe heat exchanger modules 6 vertically arranged and parallel to each other;

[0027] The heat pipe heat exchanger module 6 includes an air duct 2 and a flue 3 separated from each other. A heat pipe heat exchanger 5 is installed in each heat pipe heat exchanger module 6. The heat pipe heat exchanger 5 spans the air duct 2 and the flue 3. The heat pipe heat exchanger 5 includes an evaporation section and a condensation section. The evaporation section of the heat pipe heat exchanger 5 is placed in the flue 3, and the condensation section of the heat pipe heat exchanger 5 is placed in the air duct 2. The heat pipe heat exchanger 5 adopts a gravity heat pipe. The evaporation section of the heat pipe heat exchanger 5 is lower than the condensation section, forming a 5 The heat pipe heat exchanger 5 is arranged at an angle of 1°. The inlet temperature of the primary and secondary air of the rotary air preheater 4 is increased, the heat exchange capacity of the rotary air preheater 4 is reduced, and the outlet flue gas temperature of the rotary air preheater 4 is maintained above 220°C, completely preventing the acid dew corrosion blockage and ammonium bisulfate blockage of the rotary air preheater 4. Each heat pipe heat exchanger module 6 is placed at the bottom air inlet on the side of the air duct 2 and is provided with an openable and closable baffle 7, which has only two states: fully open and fully closed. After the heat pipe heat exchanger 5 is blocked by ash, the air side baffle 7 of the corresponding heat pipe heat exchanger module 6 is closed in turn. When the air baffle 7 is closed, the metal temperature of the heat pipe of the heat pipe heat exchanger module 6 rises to above 220°C, the ammonium bisulfate is gasified, and the scale is quickly blown off by the flue gas, keeping the heating surface of the heat pipe heat exchanger 5 clean.

[0028] Both ends of the inlet and outlet of the air duct 2 of the heat pipe heat exchanger module 6 are provided with an air duct pressure transmitter 8 and an air duct temperature transmitter 9, which are located on the inner side of the baffle 7 to measure the changes in the pressure and temperature of the primary air and secondary air of the preheater; both ends of the inlet and outlet of the flue 3 of the heat pipe heat exchanger module 6 are provided with a flue pressure transmitter 10 and a flue temperature transmitter 11 to measure the changes in the flue gas pressure and temperature; the evaporation section of the heat pipe heat exchanger 5 is horizontally distributed with metal wall temperature measuring points, and the number of the metal wall temperature measuring points is 3-5, which measure the metal temperature distribution of the heat pipe along the cross-section of the module and the changes in the metal wall temperature; according to the changes in the inlet and outlet pressure and temperature of the flue gas, it is judged whether the heat pipe heat exchanger 5 is blocked and the severity of the blockage, and according to the changes in the metal wall temperature of the heat pipes of each module, it is judged which heat pipe heat exchanger module 6 is blocked.

[0029] Specifically, the evaporation section and the condensation section of the heat pipe heat exchanger 5 are both provided with fins to increase the heat exchange area.

[0030] Specifically, the baffle 7 is electrically connected to an electric actuator to control the opening and closing of the baffle 7. When the baffle 7 is closed for scaling cleaning, it is ensured that only one baffle 7 of a heat pipe exchanger module 6 is in a closed state, and multiple heat pipe exchanger modules 6 cannot be cleaned at the same time.

[0031] The working principle of an embodiment of the utility model: the heat pipe heat exchanger 5 of the utility model increases the inlet temperature of the primary and secondary air of the rotary air preheater 4, reduces the heat exchange capacity of the rotary air preheater 4, keeps the outlet flue gas temperature of the rotary air preheater 4 above 220°C, completely prevents the rotary air preheater 4 from acid dew corrosion blockage and ammonium bisulfate blockage, and the acid dew corrosion blockage and ammonium bisulfate blockage are transferred to the heat pipe heat exchanger 5. The heat pipe heat exchanger 5 is modularly designed, and the heat pipe heat exchanger modules 6 are arranged in parallel. The baffles 7 of the heat pipe heat exchanger modules 6 are closed in turn to dry burn the heat pipe heat exchanger modules 6. The metal wall temperature of the evaporation section of the heat pipe heat exchanger 5 of the heat pipe heat exchanger module 6 rises to above 220°C, the ammonium bisulfate is gasified, and the scaling is taken away by the flushing of the flue gas flow, thereby achieving a self-cleaning function.

Claims

1. A heat pipe air preheater system, characterized in that: It comprises a main body (1) and a rotary air preheater (4), wherein the main body (1) is arranged at the bottom of the rotary air preheater (4), and the main body (1) is composed of a plurality of heat pipe heat exchanger modules (6) vertically arranged and parallel to each other; The heat pipe heat exchanger module (6) comprises an air duct (2) and a flue (3) separated from each other, and each heat pipe heat exchanger module (6) is equipped with a heat pipe heat exchanger (5), the heat pipe heat exchanger (5) spans the air duct (2) and the flue (3), and the heat pipe heat exchanger (5) comprises an evaporation section and a condensation section, the evaporation section of the heat pipe heat exchanger (5) is arranged in the flue (3), and the condensation section of the heat pipe heat exchanger (5) is arranged in the air duct (2), and the bottom air inlet of the air duct (2) of each heat pipe heat exchanger module (6) is provided with a baffle (7) that can be opened and closed.

2. A heat pipe air preheater system according to claim 1, characterized in that: An air duct pressure transmitter (8) and an air duct temperature transmitter (9) are provided at both ends of the inlet and outlet of the air duct (2) of the heat pipe heat exchanger module (6), and the air duct pressure transmitter (8) and the air duct temperature transmitter (9) are located on the inner side of the baffle (7).

3. A heat pipe air preheater system according to claim 2, characterized in that: Both inlet and outlet ends of the flue (3) of the heat pipe heat exchanger module (6) are provided with a flue pressure transmitter (10) and a flue temperature transmitter (11).

4. A heat pipe air preheater system according to claim 1, characterized in that: The evaporation section and the condensation section of the heat pipe heat exchanger (5) are both provided with fins.

5. The heat pipe air preheater system according to claim 1, characterized in that: The heat pipe heat exchanger (5) adopts a gravity heat pipe, and the evaporation section of the heat pipe heat exchanger (5) is lower than the condensation section and is arranged at an inclination of 5°.

6. A heat pipe air preheater system according to claim 1 or 3, characterized in that: The baffle (7) is electrically connected to an electric actuator.

7. The heat pipe air preheater system according to claim 1, characterized in that: The evaporation section of the heat pipe heat exchanger (5) is provided with metal wall temperature measuring points distributed in the transverse direction, and the number of the metal wall temperature measuring points is 3-5.

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