CN213746825U - Flue gas cooler with adjustable flue gas velocity of flow - Google Patents

Flue gas cooler with adjustable flue gas velocity of flow Download PDF

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Publication number
CN213746825U
CN213746825U CN202022792669.2U CN202022792669U CN213746825U CN 213746825 U CN213746825 U CN 213746825U CN 202022792669 U CN202022792669 U CN 202022792669U CN 213746825 U CN213746825 U CN 213746825U
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flue gas
heat exchange
gas cooler
adjustable
exchange modules
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杨辉
党黎军
党小建
沈植
张宇博
贾明祥
何未雨
姚佳鑫
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Xian Thermal Power Research Institute Co Ltd
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Xian Thermal Power Research Institute 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
    • Y02E20/30Technologies for a more efficient combustion or heat usage

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Abstract

A flue gas cooler with adjustable flue gas flow velocity comprises a shell and a plurality of groups of heat exchange modules arranged in the shell, wherein the heat exchange modules are separated by flue plates, each heat exchange module is formed by connecting a plurality of stages of heat exchange tubes, and an adjustable flue gas baffle is arranged behind the last stage of heat exchange tube along the flow direction of flue gas; and the front and the rear of each group of heat exchange modules are respectively provided with a pressure measuring point. The utility model discloses a flue gas baffle's aperture changes, can be on-line adjustment flue gas flow in this group of module, and then has changed the flue gas velocity of flow in this group of module, eliminates stifled ash through changing the flue gas velocity of flow, can adjust differential pressure to normal level simultaneously.

Description

Flue gas cooler with adjustable flue gas velocity of flow
Technical Field
The utility model belongs to coal fired power plant boiler field, concretely relates to flue gas cooler with adjustable flue gas velocity of flow.
Background
The flue gas cooler recovers the waste heat of the discharged smoke of the coal-fired power station boiler and is used for heating condensed water, return water of a heat supply network and air temperature at the inlet of a fan so as to improve the overall economy of the coal-fired power generating set and reduce the coal consumption of power generation. The flue gas cooler is arranged in a flue between the air preheater of the boiler and the electric dust remover, the temperature of the flue gas at the outlet of the air preheater is reduced to 90-110 ℃ from 120-160 ℃, the temperature of the water at the inlet of a cooling medium (condensed water and return water of a heat supply network) is more than 70 ℃, and the temperature of the water at the outlet is more than 95 ℃.
Because the heat transfer temperature and pressure are small, in order to recover the waste heat of the exhaust smoke to the maximum extent, the smoke cooler adopts a countercurrent flow heat exchange mode, the arrangement of the heat exchange tubes is compact, and once the heat exchange tubes leak, only a mode of cutting off and isolating can be adopted. In recent years, more domestic coal-fired power plant unit flue gas coolers are thoroughly isolated due to large-area leakage and are forced to be integrally replaced; the pressure difference of the flue gas side is large in the operation of some flue gas coolers, so that the output of a draught fan is insufficient, and the load capacity of a unit is influenced. The main reason for the leakage of the flue gas cooler is abrasion leakage caused by high local flue gas flow velocity, and the reason for causing the high local flue gas flow velocity is that most of the flue gas coolers of the power plant are modified and installed after the unit is built, and is limited by the arrangement of the original flue gas channel, the front straight section area of the heating surface is short, and the inlet flow field is difficult to reach uniformity, so that the high local flue gas flow velocity in the flue gas cooler is caused, and the abrasion leakage occurs. The main reason that the flue gas side differential pressure of the flue gas cooler is higher is that the flue gas cooler has the ash blockage problem, and the ash blockage caused mainly has three reasons: (1) local ash accumulation and blockage caused by low local flue gas flow velocity or uneven fly ash concentration in the flue gas; (2) the ammonia escape rate of the burning high-sulfur coal or the denitration system is high, and when ammonium bisulfate is deposited, the fly ash in the flue gas has high viscosity, and the flue gas forms accumulated ash when flowing through the flue gas cooler; (3) the ash deposition is caused by unreasonable structure position of the flue gas cooler, if the low-temperature coal economizer arranged in the horizontal flue has the problem of more or less lower ash deposition, the flue gas cooler with the heat exchange tube adopting the spiral finned tube is easy to block ash.
Aiming at the problems of leakage and ash blockage of the flue gas cooler, the problems of leakage and ash blockage of the flue gas cooler can be directly solved if the flow rate of the flue gas in the flue of the flue gas cooler can be adjusted on line.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a flue gas cooler with adjustable flue gas velocity of flow problem to revealing and stifled grey problem that flue gas cooler exists among the above-mentioned prior art, avoid local flue gas velocity of flow too high, adjust flue gas side differential pressure to normal level.
In order to achieve the above object, the present invention provides the following technical solutions:
a flue gas cooler with adjustable flue gas flow velocity comprises a shell and a plurality of groups of heat exchange modules arranged in the shell, wherein the heat exchange modules are separated by flue plates, the heat exchange modules are formed by connecting a plurality of stages of heat exchange tubes, and an adjustable flue gas baffle is arranged behind the last stage of heat exchange tube along the flow direction of flue gas; and the front and the rear of each group of heat exchange modules are respectively provided with a pressure measuring point.
Preferably, the shell is arranged in a flue between the air preheater and the dust remover of the coal-fired power plant boiler.
Preferably, the flue gas cooler can be arranged horizontally or vertically, the plurality of groups of heat exchange modules are arranged from low to high when the flue gas cooler is arranged horizontally, and the plurality of groups of heat exchange modules are arranged from front to back when the flue gas cooler is arranged vertically.
Preferably, the heat exchange modules in the same group are divided into a high-temperature section and a low-temperature section, or the high-temperature section, the medium-temperature section and the low-temperature section.
Preferably, the heat exchange tube is an H-shaped finned tube or a spiral finned tube.
Preferably, the smoke baffle is controlled by an electric actuating mechanism and comprises a long shaft and blades; the long shaft is arranged along the width direction of the flue gas cooler; the electric actuating mechanism drives the long shaft to rotate circularly, and the blades fixed on the long shaft rotate along with the long shaft.
Preferably, the rotation mode of the blades is divided bin type, split type or shutter type; the shape of the blade is rectangular, and the material is stainless steel.
Preferably, the number of the flue gas baffles is the same as that of the heat exchange modules, a single flue gas baffle can cover the projection area of the single group of heat exchange modules along the flow direction of flue gas, and the opening degree of the single flue gas baffle is adjusted within the range of 0-100%.
Preferably, the sum of the opening degrees of the flue gas baffles corresponding to all the groups of heat exchange modules during the operation of the flue gas cooler is greater than the number of the heat exchange modules multiplied by 60%.
Preferably, the pressure measuring points in front of and behind the same group of heat exchange modules are on a straight line.
Compared with the prior art, the utility model discloses following beneficial effect has: the flue gas cooler heat exchange module group is isolated by a flue plate, the tail part of the flue gas cooler heat exchange module group is provided with a plurality of groups of flue gas baffles, the flue gas flow in the group of modules can be adjusted on line through the opening change of the flue gas baffles, and then the flue gas flow speed in the group of modules is changed. When the module is blocked by ash and the front-back differential pressure is larger, the opening degrees of the smoke baffles of the other modules are reduced, the opening degrees of the smoke baffles corresponding to the group of modules are increased, the smoke flow rate is increased to eliminate the ash blocking problem, and the differential pressure value of the module is restored to a normal level; when the flue gas velocity in the module is large and the front-back differential pressure is low, the opening degree of the flue gas baffle of the group of modules is reduced, and the opening degrees of the other modules are increased to correspond to the opening degree of the flue gas baffle, so that the problem of large local flue gas velocity can be solved.
Drawings
FIG. 1 is a schematic view of an assembly structure of the present invention;
FIG. 2 is a schematic structural view of the flue gas baffle of the present invention at 0% opening;
FIG. 3 is a schematic structural view of the flue gas baffle of the present invention at an opening of 100%;
FIG. 4 is a schematic structural view of the flue gas baffle of the present invention;
in the drawings: 1-a heat exchange module; 2-flue plate; 3, heat exchange tubes; 4-a flue gas baffle; 5-measuring pressure; 6-air preheater; 7-a dust remover; 8-high temperature section; 9-low temperature section; 10-an electric actuator; 11-long axis; 12-blade.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Referring to fig. 1-4, the utility model discloses flue gas cooler with adjustable flue gas velocity of flow, including the casing and arrange at the inside multiunit heat exchange module 1 of casing, the casing is arranged in the flue between coal fired power plant boiler air heater 6 and dust remover 7. The heat exchange modules 1 are separated by flue plates 2, each heat exchange module 1 is formed by connecting a plurality of stages of heat exchange tubes 3, and an adjustable flue gas baffle 4 is arranged behind the last stage of heat exchange tube 3 along the flue gas flow direction. The front and the rear of each group of heat exchange modules 1 are respectively provided with a pressure measuring point 5, and the number of the pressure measuring points 5 is twice of that of the heat exchange modules 1. The flue gas cooler can arrange or vertical arranging horizontally, arranges a plurality of groups of heat exchange modules 1 from low to high when the flue gas cooler is arranged horizontally, arranges a plurality of groups of heat exchange modules 1 from head to back when the flue gas cooler is arranged vertically. The heat exchange modules 1 in the same group are divided into a high-temperature section 8 and a low-temperature section 9, or the high-temperature section 8, a medium-temperature section and the low-temperature section 9. The heat exchange tube 3 is an H-shaped finned tube or a spiral finned tube. The smoke baffle 4 is controlled by an electric actuator 10 and comprises a long shaft 11 and blades 12; the long shaft 11 is arranged along the width direction of the flue gas cooler; the electric actuator 10 drives the long shaft 11 to rotate in a circular manner, and the blades 12 fixed to the long shaft 11 rotate in accordance therewith. The rotation mode of the blades 12 is a divided bin type, a split type or a shutter type; the blades 12 are rectangular in shape and are made of stainless steel. The number of the flue gas baffles 4 is the same as that of the heat exchange modules 1, a single flue gas baffle 4 can cover the projection area of the single group of heat exchange modules 1 along the flow direction of flue gas, the opening degree of the single flue gas baffle 4 is adjusted within the range of 0-100%, 0 is a fully-closed position, and 100% is a fully-opened position. The sum of the opening degrees of the flue gas baffles 4 corresponding to all the groups of heat exchange modules 1 is larger than the number of the heat exchange modules 1 multiplied by 60 percent during the operation period of the flue gas cooler. The pressure measuring points 5 at the front and the rear of the same heat exchange module 1 are on the same straight line, namely if the heat exchange module is a horizontally arranged flue gas cooler, the front and the rear pressure measuring points 5 corresponding to the single module 1 are on the same horizontal line; if the smoke cooler is vertically arranged, the front pressure measuring point 5 and the rear pressure measuring point 5 corresponding to the single group of modules 1 are on the same vertical line. The utility model discloses a flue gas cooler can be through keeping watch on 5 differences of pressure measurement station around every group module during operation, adjusts the aperture of flue gas baffle 4 on line.
The working principle of the utility model is as follows: the flue gas cooler is composed of heat exchange tubes, and can be thinned due to the abrasion of fly ash in flue gas. The abrasion loss of the heat exchange tube is related to the material of the heat exchange tube, the impact rate of fly ash particles and the speed of the fly ash particles (the flow speed of flue gas), wherein the abrasion loss of the heat exchange tube is in direct proportion to the 3-time power of the flow speed of the flue gas, so the flow speed of the flue gas in the flue gas cooler is controlled within a normal range.
Taking a flue gas cooler horizontally arranged between an air preheater and an electric dust remover as an example, the flue gas cooler is divided into a high-temperature section 8 and a low-temperature section 9 along the flow direction of flue gas, the high-temperature section 8 and the low-temperature section 9 are respectively provided with 3 groups of heat exchange modules 1 from low to high, the heat exchange modules are respectively named as a first group, a second group and a third group from low to high, and each group of heat exchange modules 1 is isolated by a flue plate 2. Pressure measuring points 5 are arranged in the front of the flue gas flow of the first group of heat exchange modules of the high-temperature section 8, pressure measuring points 5 are also arranged in the rear of the flue gas flow of the first group of heat exchange modules of the low-temperature section 9, and the pressure measuring points 5 of the same group of modules are in the same horizontal position. The flue gas baffle 4 corresponding to the first group of heat exchange modules is positioned behind the first group of heat exchange modules at the low temperature section, and when the baffle blades are positioned at the vertical position (namely 0% opening), the projection area of the first group of modules along the flow direction of the flue gas can be completely covered. The pressure measuring points 5 and the smoke baffle 4 of the other modules are arranged in the same way.
In the flue gas cooler of the present invention, the flue gas baffle 4 is used as a variable resistance element, and the resistance coefficient thereof is related to the baffle opening. Through the isolation of flue plate 2, parallel flue has been formed between the flue gas cooler module, through changing the aperture of every group module rear flue gas baffle 4, realizes increasing or reducing the resistance of this module flue to change the distribution proportion of flue gas in multiunit module flue, thereby realized the purpose of online adjustment flue gas velocity in every group module.
The front and rear pressure measuring points 5 corresponding to the heat exchange module 1 test the static pressure value of the position where the heat exchange module is located, and the smoke side differential pressure of a certain group of modules can be obtained by subtracting the front and rear pressure measuring values of the same group of modules. When the flue flow field where the flue gas cooler is located is uniform, and no ash blockage or local flue gas corridor exists in the heat exchange tube, the flow velocity of flue gas in the three groups of heat exchange modules 1 is close, the difference value of front and rear pressure measuring points of each corresponding group of modules is also close, and the three groups of flue gas baffles 4 are in horizontal positions (namely 100% opening). If local ash blockage exists in the heat exchange tube 3 during operation, the difference value of the front and rear pressure measuring points corresponding to the heat exchange module 1 is higher than that of the other modules. At the moment, the opening degree of the corresponding flue gas baffle 4 of the module is still 100%, and the flue gas baffles 4 corresponding to the other modules are synchronously closed, so that the flue gas flow in the heat exchange module 1 with local ash blockage can be relatively increased and the flue gas flow rate is increased by adjusting the opening degrees of the flue gas baffles 4 corresponding to different heat exchange modules 1; the flow of the flue gas in the other heat exchange modules 1 is relatively reduced, and the flow speed of the flue gas is reduced. Because the heat exchange module 1 with local ash blockage increases the flow velocity of the flue gas and the carrying capacity of the fly ash is enhanced, the deposited ash deposited and adhered on the module group flows to the dust remover 7 along with the flue gas, and the problem of local ash blockage is solved; the flue gas flow rate of the rest of the heat exchange modules 1 is controlled, so that the formation of flue gas corridors in the rest of the heat exchange modules 1 caused by local ash blockage can be prevented, and the aim of preventing the abrasion rate of the heat exchange tube from being accelerated is fulfilled. It is worth noting that the opening degrees of the flue gas baffles 4 corresponding to the other heat exchange modules 1 are controlled by a PID control system, but the sum of the opening degrees of the flue gas baffles corresponding to the three groups of modules is ensured to be 180% so as to prevent the total opening degree of the flue gas baffles from being lower to influence the circulation of the flue gas.
When the flow field of the flue gas cooler is uneven and the flow rate of the flue gas in a certain group of heat exchange modules 1 is higher, the front and rear pressure measuring points corresponding to the group of modules are lower than the rest of modules. At this time, the opening degree of the flue gas baffle corresponding to the group of modules is reduced (controlled by a PID control system), and the opening degree of the flue gas baffles corresponding to the rest of heat exchange modules 1 is kept at 100%. Through the opening adjustment of the flue gas baffle 4, the flow resistance of the heat exchange module 1 with higher flue gas flow velocity is increased, and the amount of the circulating flue gas and the flue gas flow velocity are reduced.
When a certain group of modules is in operation, the water inlet valve is closed due to leakage, the flue gas baffle 4 corresponding to the group of modules is kept at a proper opening degree, and the flue gas flow velocity in other modules is prevented from being accelerated due to the fact that the flue gas baffle 4 of the group of modules is closed.
The above-described preferred embodiments of the present invention are not intended to limit the present invention, and it should be understood by those skilled in the art that the present invention can be modified and replaced by other simple modifications and replacements without departing from the spirit and principle of the present invention, and these modifications and replacements also fall within the protection scope of the appended claims.

Claims (10)

1. A flue gas cooler with adjustable flue gas velocity is characterized in that: the heat exchange device comprises a shell and a plurality of groups of heat exchange modules (1) arranged in the shell, wherein the heat exchange modules (1) are separated by flue plates (2), each heat exchange module (1) is formed by connecting a plurality of stages of heat exchange tubes (3), and an adjustable flue gas baffle (4) is arranged behind the last stage of heat exchange tube (3) along the flow direction of flue gas; the front and the rear of each group of heat exchange modules (1) are respectively provided with a pressure measuring point (5).
2. The flue gas cooler with the adjustable flue gas flow speed according to claim 1, is characterized in that:
the shell is arranged in a flue between an air preheater (6) and a dust remover (7) of the coal-fired power plant boiler.
3. The flue gas cooler with the adjustable flue gas flow speed according to claim 2, is characterized in that:
the flue gas cooler can be arranged horizontally or vertically, a plurality of groups of heat exchange modules (1) are arranged from low to high when the flue gas cooler is arranged horizontally, and a plurality of groups of heat exchange modules (1) are arranged from head to back when the flue gas cooler is arranged vertically.
4. The flue gas cooler with the adjustable flue gas flow speed according to claim 2, is characterized in that: the heat exchange modules (1) in the same group are divided into a high-temperature section (8) and a low-temperature section (9), or the high-temperature section (8), a medium-temperature section and the low-temperature section (9).
5. The flue gas cooler with the adjustable flue gas flow speed according to claim 1, is characterized in that:
the heat exchange tubes (3) are H-shaped finned tubes or spiral finned tubes.
6. The flue gas cooler with the adjustable flue gas flow speed according to claim 1, is characterized in that:
the smoke baffle (4) is controlled by an electric actuating mechanism (10) and comprises a long shaft (11) and blades (12);
the long shaft (11) is arranged along the width direction of the flue gas cooler; the electric actuator (10) drives the long shaft (11) to rotate circularly, and the blades (12) fixed on the long shaft (11) rotate along with the long shaft.
7. The flue gas cooler with the adjustable flue gas flow speed according to claim 6, is characterized in that:
the rotation mode of the blades (12) is a divided bin type, a split type or a shutter type;
the blades (12) are rectangular and made of stainless steel.
8. The flue gas cooler with the adjustable flue gas flow speed according to claim 1, is characterized in that:
the number of the flue gas baffles (4) is the same as that of the heat exchange modules (1), a single flue gas baffle (4) can cover the projection area of the single group of heat exchange modules (1) along the flow direction of flue gas, and the opening degree of the single flue gas baffle (4) is adjusted within the range of 0-100%.
9. The flue gas cooler with adjustable flue gas flow velocity according to claim 8, is characterized in that: the sum of the opening degrees of the flue gas baffles (4) corresponding to all the groups of heat exchange modules (1) is larger than the number of the heat exchange modules (1) multiplied by 60 percent during the operation period of the flue gas cooler.
10. The flue gas cooler with the adjustable flue gas flow speed according to claim 1, is characterized in that:
the pressure measuring points (5) at the front and the rear of the same group of heat exchange modules (1) are on the same straight line.
CN202022792669.2U 2020-11-26 2020-11-26 Flue gas cooler with adjustable flue gas velocity of flow Active CN213746825U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202022792669.2U CN213746825U (en) 2020-11-26 2020-11-26 Flue gas cooler with adjustable flue gas velocity of flow

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202022792669.2U CN213746825U (en) 2020-11-26 2020-11-26 Flue gas cooler with adjustable flue gas velocity of flow

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Publication Number Publication Date
CN213746825U true CN213746825U (en) 2021-07-20

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CN202022792669.2U Active CN213746825U (en) 2020-11-26 2020-11-26 Flue gas cooler with adjustable flue gas velocity of flow

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