CN220205795U - Flue gas treatment system of coal-fired boiler - Google Patents

Flue gas treatment system of coal-fired boiler Download PDF

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Publication number
CN220205795U
CN220205795U CN202321752315.2U CN202321752315U CN220205795U CN 220205795 U CN220205795 U CN 220205795U CN 202321752315 U CN202321752315 U CN 202321752315U CN 220205795 U CN220205795 U CN 220205795U
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air
flue gas
temperature
boiler
duct
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王键
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Chongqing Xinshun Shengda Technology Co ltd
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Chongqing Xinshun Shengda Technology Co ltd
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00Combustion technologies with mitigation potential
    • Y02E20/34Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery

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Abstract

The utility model provides a flue gas treatment system of a coal-fired boiler, which comprises a boiler, a denitration device, a rotary air preheater, a flue gas heater, an electrostatic precipitator, an induced draft fan, a desulfurizing tower and a chimney which are sequentially connected, wherein flue gas sequentially flows through the denitration device, the rotary air preheater, the flue gas heater, the electrostatic precipitator, the induced draft fan, the desulfurizing tower and the chimney after being discharged from the boiler, and then is discharged to the atmosphere, an air supply duct is arranged at the air inlet side of the flue gas heater, the air outlet side of the flue gas heater is connected with the air inlet of the rotary air preheater through the air duct, and the air outlet of the rotary air preheater is connected with the boiler and the air supply duct through the high-temperature air duct. The utility model introduces high-speed and high-pressure high-temperature air into the air side of the flue gas heater, has good flow field, is insensitive to the load change of the boiler, obviously reduces the sensitivity to the tightness of the wind shield door, and is beneficial to the anti-blocking and energy saving of the rotary air preheater of the boiler.

Description

Flue gas treatment system of coal-fired boiler
Technical Field
The utility model belongs to the technical field of smoke exhaust systems of coal-fired boilers, and particularly relates to a smoke treatment system of a coal-fired boiler.
Background
The prior document CN112097287B discloses a boiler energy-saving and flue gas whitening system, which comprises a boiler, a denitrification device, a rotary air preheater, a mixed air heater, a flue gas heater, an electrostatic precipitator, a desulfurizing tower and a chimney which are sequentially connected, wherein an air outlet of the flue gas heater is connected with an air inlet of the rotary air preheater through a warm air pipeline, an air outlet of the rotary air preheater is connected with the boiler through a hot air pipeline, and an air outlet of the mixed air heater is connected with a flue between the desulfurizing tower and the chimney through a mixed air pipeline. In order to further prevent hydrogen sulfate from blocking the air mixing heater and the flue gas heater, a flue between the rotary air preheater and the electrostatic precipitator is divided into a plurality of groups of independent flue gas channels, the air mixing heater and the flue gas heater are sequentially arranged in each group of independent flue gas channels, independent partition parts (partition parts adopt partition doors, partition valves or partition plates) are arranged on the air inlet sides of the air mixing heater and the flue gas heater, and high-temperature gaseous media are introduced into the independent flue gas channels through medium interfaces to form a dry combustion flue. And during dry combustion, the partition part is closed, and a high-temperature gaseous medium is introduced to dry-burn the flue gas channel, so that ammonium bisulfate deposited on the surfaces of the heat exchange tube and the flue gas channel is gasified, and the heat exchanger is prevented from being blocked by the ammonium bisulfate.
The scheme is that high-temperature hot air or high-temperature flue gas at the outlet of the rotary air preheater is introduced into the inlet of the flue gas heater, and after being mixed with medium-temperature flue gas (190 ℃) at the inlet of the flue gas heater, the mixed flue gas is utilized to carry out local and alternate dry combustion on a plurality of pipe boxes grouped by the flue gas heater. However, this approach has the following problems: under normal conditions, the high-temperature flue gas quantity introduced into the flue gas heater is less than 1/2 of the flue gas quantity entering a pipe box of the flue gas heater, the temperature of the mixed flue gas is lower than 253 ℃, the temperature difference between the mixed flue gas and the medium-temperature flue gas at 190 ℃ is lower than 63 ℃, and the highest metal wall temperature of a heat exchange pipe is lower than 253 ℃; the change of the load of the boiler has a great influence on the flow field of the mixed high-temperature flue gas and medium-temperature flue gas; the heat loss during dry burning is larger; the metal wall temperature of the heat exchange tube of the flue gas heater is increased to 253 ℃ for a long time.
Disclosure of Invention
Aiming at one or more technical problems mentioned in the background art, the utility model aims to provide a flue gas treatment system and a dry combustion method of a coal-fired boiler.
The utility model adopts the following technical scheme.
The utility model provides a coal fired boiler flue gas processing system, including the boiler that connects in proper order, denitrification facility, rotary air heater, flue gas heater, electrostatic precipitator, the draught fan, desulfurizing tower and chimney, flue gas flows through denitrification facility in proper order from the boiler exhaust back, rotary air heater, flue gas heater, electrostatic precipitator, the draught fan, the desulfurizing tower is discharged to atmospheric environment again after chimney, air inlet side at flue gas heater is provided with the air supply wind channel, flue gas heater air outlet side passes through the air inlet of wind channel connection rotary air heater, rotary air heater's air outlet passes through high temperature wind channel connection boiler and air supply wind channel.
In order to optimize the hot air fullness/flow field of the lower region of the tube box/heat exchange tube of the flue gas heater, a blower is arranged on the air supply duct of the air inlet side of the flue gas heater.
Further, a dry-burning valve is arranged on the high-temperature air duct, and a wind blocking door is arranged on the air supply duct and between the blower 8 and the flue gas heater.
Further, the high-temperature air duct is provided with one or more branches, each branch is connected with an air supply duct which corresponds to the branch and is provided with a blocking air door, and each branch is provided with a dry combustion valve.
In order to smoothly send the high-temperature air into the pipe box/heat exchange pipe of the flue gas heater, a main valve and a high-temperature high-pressure blower are arranged on the high-temperature air duct.
In the utility model, when the dry combustion valve is in an open state, high-temperature air at the air outlet of the rotary air preheater enters the air supply duct, so that the temperature of the pipe wall of the flue gas heater is increased.
According to the utility model, high-temperature air at the air outlet of the rotary air preheater is pressurized by the high-temperature blower and then introduced into the air inlet side of the flue gas heater as a heat source, so that the tube box/heat exchange tube of the flue gas heater is subjected to dry combustion, and the ammonium bisulfate deposited on the surface of the heat exchange tube is ensured to be gasified rapidly.
The beneficial effects are that: the utility model introduces high-speed and high-pressure high-temperature air into the air side of the flue gas heater, so that the flow field is good, the boiler load change is insensitive, and the tightness sensitivity of the wind shield door is obviously reduced; the utility model can utilize 340 ℃ high-temperature wind and 190 ℃ flue gas to heat the heat exchange tube of the flue gas heater bidirectionally in a surface heat exchange mode, can rapidly raise the lowest metal wall temperature (about 60 ℃) of the heat exchange tube of the flue gas heater to more than 190 ℃, can rapidly raise the metal wall temperature of the heat exchange tube of 60 ℃ to 340 ℃ at the highest, when the flue gas flow is cut off, the dry heating effect in the state is optimal, even if the air side flow field is uneven, the metal wall temperature can be rapidly raised by utilizing the heat conduction capability of the metal, and the ammonium bisulfate deposited on the surface of the heat exchange tube is ensured to be rapidly gasified; the temperature of the hot air at the outlet of the flue gas heater is increased, which is beneficial to dry combustion and anti-blocking and energy saving of the rotary air preheater of the boiler; in addition, the utility model has the advantage of small heat loss during dry combustion.
Drawings
FIG. 1 is a schematic view of a flue gas treatment system of a coal-fired boiler in example 1;
FIG. 2 is a schematic diagram of a flue gas treatment system for a coal-fired boiler in example 2;
fig. 3 is a schematic diagram showing a simulation of a dry combustion state flow field in a tube box of the flue gas treatment system of the coal-fired boiler in example 2.
Detailed Description
The following description of the embodiments of the present utility model will be apparent and complete, and it is to be understood that the embodiments described are merely some, but not all embodiments of the present utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
Referring to fig. 1, a flue gas treatment system for a coal-fired boiler comprises a boiler 1, a denitration device 2, a rotary air preheater 4, a flue gas heater 12, an electrostatic precipitator 13, a draught fan 14, a desulfurizing tower 15 and a chimney 16 which are sequentially connected, wherein flue gas is discharged from the boiler 1 and then sequentially flows through the denitration device 2, the rotary air preheater 4, the flue gas heater 12, the electrostatic precipitator 13, the draught fan 14, the desulfurizing tower 15 and the chimney 16 and then is discharged to the atmosphere, an air supply duct is arranged at the air inlet side of the flue gas heater 12, the air outlet side of the flue gas heater 12 is connected with the air inlet of the rotary air preheater 4 through the air duct, and the air outlet of the rotary air preheater 4 is connected with the boiler 1 and the air supply duct 20 through a high-temperature air duct 19.
In the present embodiment, the blower 8 is provided on the air supply duct 20 on the air inlet side of the flue gas heater 12; a dry combustion valve 6 is arranged on the high-temperature air duct 19, and a damper 11 is arranged on the air supply duct 20 and positioned between the blower 8 and the flue gas heater 12; a main valve 3 and a high-temperature high-pressure blower 5 are arranged on the high-temperature air duct 19. When the dry combustion valve 6 is in an open state, high-temperature air at the air outlet of the rotary air preheater 4 enters the air supply duct 20, so that the temperature of the pipe wall of the flue gas heater 12 is increased. When the device is used, high-temperature air at the air outlet of the rotary air preheater is pressurized by the high-temperature blower and then is introduced into the air inlet side of the flue gas heater as a heat source, and dry heating is carried out on a tube box/heat exchange tube of the flue gas heater, so that the ammonium bisulfate deposited on the surface of the heat exchange tube is ensured to be gasified rapidly.
A dry combustion method employing the flue gas treatment system of coal-fired boiler of example 1, comprising the steps of:
closing the air blocking door 11, opening the main valve 3, the dry combustion valve 6 and the high-temperature high-pressure blower 5, and introducing high-temperature air at the air outlet of the rotary air preheater 4 into the air supply duct 20 behind the blower 8, so that the metal wall temperature of the heat exchange tube of the flue gas heater 12 is raised to be higher than 220 ℃.
As shown in fig. 2, a flue gas treatment system for a coal-fired boiler, referring to example 1, differs from example 1 in that: the air outlet of the rotary air preheater 4 is also connected with the boiler 1 through a high-temperature air duct 18, the high-temperature air duct 19 is provided with two branches, each branch is connected with an air supply duct corresponding to the branch, and each branch is provided with a dry combustion valve. Specifically, one branch is an air supply duct 20, corresponds to the dry combustion valve 6 and corresponds to the air blocking door 11; the other branch is an air supply duct 21 with a blower 9, which corresponds to the dry combustion valve 7 and to the air blocking door 10.
A dry combustion method using the flue gas treatment system of the coal-fired boiler of example 2, comprising the steps of: the main valve 3, the dry combustion valve 6 and the high-temperature and high-pressure blower 5 are opened, the air blocking door 11 is closed, and primary high-temperature air at the air outlet of the rotary air preheater 4 is introduced into the air supply duct 20 behind the blower 8.
In a specific application scheme: according to the thermodynamic calculation, when the primary high-temperature air is utilized to carry out grouping dry combustion on the tube boxes of the flue gas heater 12, the high-temperature air volume required by increasing the metal wall temperature of the heat exchange tube to 210 ℃ is 12000Nm 3 /h; when secondary air pipe boxes (pipe boxes corresponding to secondary air) are subjected to dry burning in groups, primary high-temperature air (340 ℃) can be directly introduced into the cold air side of the secondary air pipe boxes of the flue gas heater 12 for dry burning; when the primary air pipe box (pipe box corresponding to primary air) of the dry-combustion flue gas heater 12 is used, the primary high-temperature air is forced to be introduced into the air side of the pipe box by using the high-temperature and high-pressure air blower 5 for dry-combustion, and the pressure head of the high-temperature and high-pressure air blower 5 is 3000pa.
When the secondary air pipe box of the dry-combustion flue gas heater 12 is used, the air blocking door 10 is closed firstly, then the main valve 3, the dry-combustion valve 7 and the high-temperature high-pressure blower 5 are opened, and 12000Nm is directly carried out 3 The primary high-temperature hot air (the temperature is 340 ℃) of/h is introduced into a secondary air pipe box of the flue gas heater 12 and then is dried and burned. When the primary air pipe box of the dry-combustion flue gas heater 12 is used, the air blocking door 11 is closed firstly, then the main valve 3, the dry-combustion valve 6 and the high-temperature high-pressure blower 5 are opened, and 12000Nm is directly carried out 3 The primary high-temperature air of/h (the temperature is 340 ℃) is introduced into the primary air pipe box of the flue gas heater 12 and then is subjected to dry combustion, and the simulation situation of the flow field in the pipe box in the state is shown in figure 2.
The utility model redefines the dry heating mode of the tube box of the flue gas heat exchanger in the flue gas treatment system of the coal-fired boiler, introduces high-speed and high-pressure high-temperature wind into the air side of the flue gas heater, has good flow field, is insensitive to the load change of the boiler, and obviously reduces the sensitivity to the tightness of the wind shield door; the utility model can utilize 340 ℃ high-temperature wind and 190 ℃ flue gas to heat the heat exchange tube of the flue gas heater bidirectionally in a surface heat exchange mode, can rapidly raise the lowest metal wall temperature (about 60 ℃) of the heat exchange tube of the flue gas heater to more than 190 ℃, can rapidly raise the metal wall temperature of the heat exchange tube of 60 ℃ to 340 ℃ at the highest, when the flue gas flow is cut off, the dry heating effect in the state is optimal, even if the air side flow field is uneven, the metal wall temperature can be rapidly raised by utilizing the heat conduction capability of the metal, and the ammonium bisulfate deposited on the surface of the heat exchange tube is ensured to be rapidly gasified; the temperature of the hot air at the outlet of the flue gas heater is increased, which is beneficial to dry combustion and anti-blocking and energy saving of the rotary air preheater of the boiler; in addition, the utility model has the advantage of small heat loss during dry combustion.

Claims (6)

1. The utility model provides a coal fired boiler flue gas processing system, boiler (1) including connecting in proper order, denitrification facility (2), rotary air heater (4), flue gas warm braw ware (12), electrostatic precipitator (13), draught fan (14), desulfurizing tower (15) and chimney (16), flue gas flows through denitrification facility (2), rotary air heater (4), flue gas warm braw ware (12), electrostatic precipitator (13), draught fan (14), desulfurizing tower (15) and chimney (16) back in proper order from boiler (1) discharge and discharges to atmospheric environment, its characterized in that again: an air supply duct is arranged at the air inlet side of the flue gas air heater (12), the air outlet side of the flue gas air heater (12) is connected with the air inlet of the rotary air preheater (4) through the duct, and the air outlet of the rotary air preheater (4) is connected with the boiler (1) and the air supply duct (20) through the high-temperature air duct (19).
2. The coal-fired boiler flue gas treatment system according to claim 1, wherein: a blower (8) is arranged on a blower duct (20) at the air inlet side of the flue gas heater (12).
3. The coal-fired boiler flue gas treatment system according to claim 1, wherein: the high-temperature air duct (19) is provided with a dry combustion valve (6), and the air supply duct (20) is provided with an air blocking door (11) between the air feeder (8) and the flue gas heater (12).
4. The coal-fired boiler flue gas treatment system according to claim 1, wherein: the high-temperature air duct (19) is provided with one or more branches, each branch is connected with an air supply duct which corresponds to the branch and is provided with a wind blocking door, and each branch is provided with a dry combustion valve.
5. The coal fired boiler flue gas treatment system according to any of claims 1-4, wherein: the high-temperature air duct (19) is provided with a main valve (3) and a high-temperature high-pressure blower (5).
6. The coal-fired boiler flue gas treatment system according to claim 5, wherein: when the dry combustion valve (6) is in an open state, high-temperature air at the air outlet of the rotary air preheater (4) enters the air supply duct (20) to raise the temperature of the pipe wall of the flue gas heater (12).
CN202321752315.2U 2023-07-05 2023-07-05 Flue gas treatment system of coal-fired boiler Active CN220205795U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202321752315.2U CN220205795U (en) 2023-07-05 2023-07-05 Flue gas treatment system of coal-fired boiler

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202321752315.2U CN220205795U (en) 2023-07-05 2023-07-05 Flue gas treatment system of coal-fired boiler

Publications (1)

Publication Number Publication Date
CN220205795U true CN220205795U (en) 2023-12-19

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202321752315.2U Active CN220205795U (en) 2023-07-05 2023-07-05 Flue gas treatment system of coal-fired boiler

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CN (1) CN220205795U (en)

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