CN218672255U

CN218672255U - Bushing type air heater of anti dew point corrosion

Info

Publication number: CN218672255U
Application number: CN202222840597.3U
Authority: CN
Inventors: 俞苗; 陈伟; 吴可欣; 刘珍; 赵剑云
Original assignee: Xizi Clean Energy Equipment Manufacturing Co ltd
Current assignee: Xizi Clean Energy Equipment Manufacturing Co ltd
Priority date: 2022-10-27
Filing date: 2022-10-27
Publication date: 2023-03-21
Anticipated expiration: 2032-10-27

Abstract

The utility model discloses an anti dew point corrosion's bushing type air heater, including air heater casing, flue gas inlet, exhanst gas outlet, air intlet, air outlet, inlet, gas vent, feed liquor valve, discharge valve, baffling board, sleeve pipe and fixed tube sheet. The casing pipe consists of an inner pipe and an outer pipe, the outer pipe is fixed on the shell by an outer fixed pipe plate, the inner pipe is fixed on the shell by an inner fixed pipe plate, and the baffle plates are fixed on the shell in a staggered manner. The flue gas temperature distribution in each inner pipe of the utility model is basically consistent, and the flue gas temperature at the outlets of all inner pipes can be controlled simultaneously by changing the medium filling amount in the outer pipe, so that the flue gas temperature is higher than the dew point temperature, the problem of heat pipe corrosion caused by too low flue gas temperature is effectively solved, and the service life of the equipment is prolonged; the utility model adjusts the medium filling amount in the pipe and further adjusts the temperature of the flue gas outlet through the liquid inlet valve, and the whole structure of the air preheater is not required to be changed, thus the operation is simple; increasing the temperature at the air outlet; the heat exchange efficiency of the air preheater is improved.

Description

Bushing type air heater of anti dew point corrosion

Technical Field

The utility model relates to a boiler waste heat utilization technical field especially relates to an anti dew point corrosion's bushing type air heater.

Background

The air preheater is a device for heating combustion air by using low-temperature waste heat of boiler exhaust smoke. After the flue gas at the tail part of the boiler flows through the air preheater, the exhaust gas temperature is reduced, and the waste heat utilization rate of the boiler is improved, so that the boiler efficiency is improved. The initial temperature of air in the hearth is increased, so that the ignition and combustion conditions of fuel are improved, and the incomplete combustion loss is reduced. The temperature in the hearth is increased, the radiation heat exchange in the furnace is strengthened, the area of a water cooling wall in unit evaporation capacity is reduced, the metal consumption is saved, and the boiler cost is reduced.

The heat pipe type air preheater is a heat exchange element for transferring heat by utilizing phase change of working medium in a pipe. The traditional air preheater is composed of an upper box body, a lower box body, a middle partition plate and a heat pipe bundle penetrating through the middle partition plate. Flue gas and air respectively go up lower tube section countercurrent flow, and high temperature flue gas makes the interior liquid of heat pipe be heated and vaporize through lower part heating section, and low temperature air flows through upper portion condensation section, and intraductal steam heat release condenses to liquid and flows to the pipe lower part, so circulation is reciprocal.

Traditional heat pipe formula air heater easily produces the corruption phenomenon, and when the flue gas temperature reduced, when the pipe wall temperature was less than flue gas dew point temperature, the sulphide that has corrosivity in the flue gas condenses into acid and attaches to the pipe wall, and then corrodes the heat exchange tube. The smoke temperature is gradually reduced along the smoke flowing direction, and the rear section heat pipe is easy to generate the low-temperature corrosion phenomenon.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem, the utility model discloses an anti dew point corrosion's bushing type air heater. The flue gas flows into the inner pipe from the inlet at the upper part of the air preheater and flows out from the outlet at the lower part of the air preheater. A certain amount of medium is injected into the gap between the inner pipe and the outer pipe. Air enters the gap between the outer pipe and the shell from the lower inlet, absorbs heat and then flows out from the upper outlet. Because the temperature distribution of the flue gas in all the inner pipes is basically unchanged, the temperature of the flue gas outlet can be higher than the dew point temperature by controlling the liquid amount in the gap between the inner pipe and the outer pipe.

The utility model adopts the following technical scheme:

the utility model provides an anti dew point corrosion's bushing type air heater, including the air heater casing, characterized by, be provided with the baffling board in the air heater casing, sleeve pipe and fixed tube sheet, the sleeve pipe comprises inner tube and outer tube, fixed tube sheet comprises outer fixed tube sheet and interior fixed tube sheet, the outer tube is fixed in on the air heater casing by outer fixed tube sheet, the inner tube is fixed in on the air heater casing by interior fixed tube sheet, the baffling board is crisscross to be fixed in on the air heater casing, the inner tube overlaps in the outer tube, the inner tube is the boiler smoke exhaust gas passageway, the inner tube upper end is the flue gas import, the inner tube lower extreme is the exhanst gas outlet, the outer tube is the heat transfer medium passageway, outer tube bottom intercommunication inlet channel, inlet channel intercommunication has the inlet, outer tube upper end intercommunication exhaust passage, exhaust passage intercommunication has the gas vent, form the air preheating channel between the inside and outside fixed tube sheet of air heater casing and baffling board, the air preheating channel lower extreme is the air inlet, the air preheating channel upper end is the air outlet.

The flue gas flows along the inner pipe after entering the shell from the upper flue gas inlet and flows out from the flue gas outlet. The medium in the outer pipe enters from the liquid inlet, and the quantity of the medium in the pipe is controlled by the liquid inlet valve. Air enters the shell from the air inlet, passes through the gap between the outer pipe and the shell along the baffle plate and then flows out from the air outlet.

Preferably, the liquid inlet channel is formed by an air preheater shell, an external fixed tube plate and an internal fixed tube plate which are fixedly connected with the lower end of the air preheater shell.

Preferably, the exhaust gas channel is formed by an air preheater housing, an outer fixed tube plate and an inner fixed tube plate fixedly connected to the upper end of the air preheater housing.

Preferably, the liquid inlet is provided with a liquid inlet valve.

Preferably, the exhaust port is provided with an exhaust valve.

Preferably, the inner pipe and the inner fixed pipe plate are fixed by welding, and the inner fixed pipe plate and the air preheater shell are fixed by welding.

Preferably, the outer pipe and the outer fixed pipe plate, the outer pipe and the baffle plate are fixed by welding, and the outer fixed pipe plate and the shell of the air preheater, and the baffle plate and the shell of the air preheater are fixed by welding.

The boiler smoke exhaust gas flows into the inner pipe from the smoke inlet, heat is transferred to the medium in the outer pipe, and the smoke exhaust gas flows out from the smoke outlet after the temperature of the smoke exhaust gas is reduced. The medium in the outer tube absorbs the heat of the flue gas to evaporate, and when the air flows through the upper part of the outer tube, the steam releases heat and is condensed into liquid to flow back to the evaporation section to evaporate again. The air to be preheated enters the shell from the lower air inlet along the baffle plate, and after the heat of the outer pipe is absorbed, the temperature of the air is increased and the air flows out from the upper air outlet.

The utility model has the advantages that:

(1) The flue gas temperature distribution in each inner pipe of the utility model is basically consistent, and the flue gas temperature at the outlets of all inner pipes can be simultaneously controlled by changing the filling amount of the medium in the outer pipe, so that the flue gas temperature is higher than the dew point temperature, the problem of heat pipe corrosion caused by too low flue gas temperature is effectively solved, and the service life of the equipment is prolonged;

(2) The outlet flue gas temperature of the traditional air preheater is regulated by changing a side heat pipe structure of the flue gas outlet, the sleeve type air preheater regulates the medium filling amount in the pipe through a liquid inlet valve so as to regulate the outlet flue gas temperature, the integral structure of the air preheater is not required to be changed, and the operation is simple;

(3) The utility model increases the contact area between the air and the tube bundle, increases the heat exchange quantity between the heating tube and the air, and increases the temperature at the air outlet;

(4) The utility model discloses the baffling board reduces the air dead zone that flows in the air heater casing for it is more even to flow, improves air heater heat exchange efficiency.

Drawings

Fig. 1 is a schematic structural view of the present invention;

in the figure: 1. an air preheater housing; 2. a flue gas inlet; 3. a flue gas outlet; 4. an air inlet; 5. an air outlet; 6. an exhaust port; 7. a baffle plate; 8. an inner tube; 9. an outer tube; 10. an inner fixed tube plate; 11. an outer fixed tube plate; 12. a liquid inlet; 13. a liquid inlet valve; 14. and (4) exhausting the valve.

Detailed Description

The technical solution of the present invention is further described in detail by the following specific embodiments in combination with the accompanying drawings:

the embodiment is as follows: as shown in fig. 1, a dew point corrosion resistant casing type air preheater comprises an air preheater shell 1, a flue gas inlet 2, a flue gas outlet 3, an air inlet 4, an air outlet 5, a liquid inlet 12, an exhaust port 6, a liquid inlet valve 13, an exhaust valve 14, a baffle plate 7, a casing and a fixed tube plate, wherein the casing is composed of an inner tube 8 and an outer tube 9, the fixed tube plate is composed of an outer fixed tube plate 11 and an inner fixed tube plate 10, the outer tube is fixed on the air preheater shell by the outer fixed tube plate, the inner tube is fixed on the air preheater shell by the inner fixed tube plate, the baffle plate is fixed on the air preheater shell in a staggered manner, the inner tube is sleeved in the outer tube, the inner tube is a boiler exhaust smoke flue gas channel, the upper end of the inner tube is a flue gas inlet, the lower end of the inner tube is a flue gas outlet, the outer tube is a heat exchange medium channel, the bottom end of the outer tube is communicated with the liquid inlet channel, the liquid inlet channel is communicated with the upper end of the outer tube, the exhaust channel is communicated with the exhaust channel, the exhaust channel is communicated with the exhaust port, the air inlet, an air inlet is formed between the inner fixed tube and the baffle plate, the air preheating channel is arranged between the air preheating channel.

The liquid inlet channel is formed by an air preheater shell, an external fixed tube plate and an internal fixed tube plate which are fixedly connected with the lower end of the air preheater shell.

The exhaust passage is formed by an air preheater shell, an external fixed tube plate and an internal fixed tube plate which are fixedly connected with the upper end of the air preheater shell.

The liquid inlet is provided with a liquid inlet valve. The exhaust port is provided with an exhaust valve.

The inner tube and the inner fixed tube plate are fixed by welding, and the inner fixed tube plate and the shell of the air preheater are fixed by welding. The outer pipe and the outer fixed pipe plate, the outer pipe and the baffle plate are fixed by welding, and the outer fixed pipe plate and the air preheater shell, and the baffle plate and the air preheater shell are fixed by welding.

The working process of the dew point corrosion resistant sleeve type air preheater comprises the following steps: the flue gas flows into the gap formed by the outer fixed tube plate and the inner tube from the flue gas inlet section, the temperature of the flue gas is gradually reduced after heat is transferred to the medium in the outer tube, and the low-temperature flue gas flows out of the air preheater shell from the flue gas outlet. The working medium enters the lower area between the outer fixed tube plate and the inner fixed tube plate through the liquid inlet and flows upwards through the gap between the outer tube and the inner tube. The working medium in the outer pipe absorbs the heat of the flue gas and then evaporates, and the outer pipe is divided into an upper steam section and a lower liquid section. Air enters the air preheater shell from the air inlet, after the heat of the outer pipe is absorbed, steam in the outer pipe is condensed into liquid and flows back to the liquid section along the pipe wall, and the temperature of the air is increased after the air and the outer pipe perform sufficient heat exchange along the baffle plate, and the air flows out of the air preheater shell from the air outlet. When the temperature of the outlet flue gas is too high, the liquid inlet valve is opened to increase the amount of the medium in the outer pipe, increase the heat absorption capacity of the medium and increase the evaporation capacity. When the non-condensable gas in the air preheater increases, the pressure in the outer pipe gradually increases, the exhaust valve is opened to reduce the pressure in the pipe, and the efficiency of the air preheater is improved. Through the process, the purpose of controlling the temperature of the flue gas outlet of the air preheater can be achieved, the exhaust gas temperature can be flexibly adjusted under different load changes, the waste heat utilization rate of the boiler is increased, and the service life of equipment is prolonged.

The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the scope of the claims.

Claims

1. The utility model provides an anti dew point corrosion's bushing type air heater, including the air heater casing, characterized by, be provided with the baffling board in the air heater casing, sleeve pipe and fixed tube sheet, the sleeve pipe comprises inner tube and outer tube, fixed tube sheet comprises outer fixed tube sheet and interior fixed tube sheet, the outer tube is fixed in on the air heater casing by outer fixed tube sheet, the inner tube is fixed in on the air heater casing by interior fixed tube sheet, the baffling board is crisscross to be fixed in on the air heater casing, the inner tube overlaps in the outer tube, the inner tube is the boiler smoke exhaust gas passageway, the inner tube upper end is the flue gas import, the inner tube lower extreme is the exhanst gas outlet, the outer tube is the heat transfer medium passageway, outer tube bottom intercommunication inlet channel, inlet channel intercommunication has the inlet, outer tube upper end intercommunication exhaust passage, exhaust passage intercommunication has the gas vent, form the air preheating channel between the inside and outside fixed tube sheet of air heater casing and baffling board, the air preheating channel lower extreme is the air inlet, the air preheating channel upper end is the air outlet.

2. A dew point corrosion resistant casing air preheater as claimed in claim 1, wherein said inlet passage is defined by an air preheater housing, an outer fixed tube sheet and an inner fixed tube sheet fixedly attached to a lower end of the air preheater housing.

3. The tube in tube air preheater of claim 1, wherein said exhaust gas passageway is defined by an air preheater housing, an outer fixed tube sheet and an inner fixed tube sheet fixedly attached to an upper end of the air preheater housing.

4. The telescopic air preheater as recited in claim 1, wherein said inlet port is provided with an inlet valve.

5. The telescopic air preheater as recited in claim 1, wherein said exhaust port is provided with an exhaust valve.

6. The tube in tube air preheater of claim 1, wherein said inner tube is secured to said inner stationary tube sheet by welding, and said inner stationary tube sheet is secured to said air preheater housing by welding.

7. The telescopic air preheater as claimed in claim 1, wherein said outer tube and said outer fixed tube plate, said outer tube and said baffle plate are fixed by welding, and said outer fixed tube plate and said air preheater housing, said baffle plate and said air preheater housing are fixed by welding.