CN117663177A - Method and system for ring-division heating and blocking-treatment of rotary air preheater - Google Patents

Method and system for ring-division heating and blocking-treatment of rotary air preheater Download PDF

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Publication number
CN117663177A
CN117663177A CN202311647357.4A CN202311647357A CN117663177A CN 117663177 A CN117663177 A CN 117663177A CN 202311647357 A CN202311647357 A CN 202311647357A CN 117663177 A CN117663177 A CN 117663177A
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China
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air
hot air
hot
arc
preheater
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王徐珩菁
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Sichuan Huisheng Zhicheng Power Engineering Co ltd
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Sichuan Huisheng Zhicheng Power Engineering Co ltd
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Priority to CN202311647357.4A priority Critical patent/CN117663177A/en
Publication of CN117663177A publication Critical patent/CN117663177A/en
Priority to CN202410336345.8A priority patent/CN118208744A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L15/00—Heating of air supplied for combustion
    • F23L15/02—Arrangements of regenerators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/005—Other auxiliary members within casings, e.g. internal filling means or sealing means
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Air Supply (AREA)

Abstract

The invention discloses a ring-dividing heating blockage-treating method and a ring-dividing heating blockage-treating system of a rotary air preheater, wherein the rotary air preheater comprises a flue gas dividing bin and at least one air dividing bin, the end face of the cold end of a rotor of the air preheater is divided into N concentric rings by an annular partition plate, N is more than or equal to 2, hot air curtain is formed by leading hot air into each concentric ring wheel corresponding to the cold end of at least one air dividing bin, resistance of cold air entering in corresponding concentric rings is increased, and wall temperature of a heat storage element in corresponding concentric rings is increased, so that blockage prevention is realized; and the area where hot air is introduced circumferentially covers 90-165 degrees of central angle of the air sub-bin at the cold end face of the air preheater rotor. According to the invention, hot air is introduced into each concentric ring wheel corresponding to the cold end of at least one air sub-bin to form a hot air curtain, so that anti-blocking is realized, and the angle of the air sub-bin covered by the hot air is large enough, so that the corresponding local smoke exhaust temperature can be greatly improved, and the ash blocking problem of the heat storage element of the air preheater is more thoroughly solved; and a split-ring cold air door is not required to be arranged.

Description

Method and system for ring-division heating and blocking-treatment of rotary air preheater
Technical Field
The invention relates to a method and a system for controlling blockage by ring separation and heating of a rotary air preheater, and belongs to the technical field of rotary air preheaters of coal-fired power plants.
Background
The rotary air preheater is a heat exchange equipment for large-scale coal-fired power station boiler, and utilizes the heat quantity of boiler flue gas to heat the air required by combustion so as to raise boiler efficiency. Most of rotary air pre-heaters comprise three sub-bins, including two air sub-bins (comprising one of a primary air sub-bin and a secondary air sub-bin) and one flue gas sub-bin; there are a few of two sub-bins, including an air sub-bin and a flue gas sub-bin; there are a few of the four sub-bins, including three air sub-bins (including one primary air sub-bin and two secondary air sub-bins) and one flue gas sub-bin. The rotary air preheater belongs to rotary equipment, and comprises a rotor and a stator, wherein the rotor consists of a large number of heat storage elements, and the rotating speed is about 1 circle/min; the upper end of the rotor is a hot end, the lower end is a cold end, and the flue gas exchanges heat with air in countercurrent from top to bottom.
The focus of attention of rotary air pre-heaters mainly comprises ash blocking, high air leakage rate, low heat transfer efficiency, serious low-temperature corrosion and the like, which affect the safe and economic operation of equipment for a long time, and especially the ash blocking problem of the air pre-heaters is most prominent. In recent years, as NOx emission requirements of a denitration device are stringent, the running environment of the air preheater is changed, and the ash blocking treatment of the air preheater is more difficult and complex.
The flue gas denitration facilities added in the existing coal-fired power stations mainly adopt a Selective Catalytic Reduction (SCR) technology. After SCR denitration technology is adopted, part of SO in the flue gas 2 Oxidation by denitration catalyst to SO 3 Increase SO in flue gas 3 Together with the unavoidable ammonia slip, resulting in ammonium bisulfate (NH) 4 HSO 4 ) And a large amount of byproducts are generated, the acid dew point temperature of the flue gas is increased, the low-temperature corrosion is aggravated, and the ash blocking problem of the air preheater is aggravated.
The by-product ammonium bisulfate (NH) 4 HSO 4 ) In the temperature range of 146-207 ℃, the heat storage element is in a molten state and can be firmly adhered to the surface of the heat storage element of the air preheater, so that the heat storage element is corroded and deposited with ash, and finally, the ash blocking can be possibly caused, thereby causing great hidden trouble to the safe operation of a unit. Some of the domestic power stations cannot solve or alleviate the problem, so that the machine set is limited in load and even forced to stop.
When the exhaust temperature is lower than the acid dew point, the sulfuric acid vapor is condensed, sulfuric acid drops are attached to the cold end heat storage element, and the heat storage element is corroded. Acid dew point of flue gas with SO 3 The concentration is increased by increasing, generally 130 to 160 ℃. Due to the addition of the denitration deviceSO 2 To SO 3 Conversion rate of SO in flue gas is improved 3 Therefore, the acid dew point of many power stations is generally higher than the exhaust gas temperature at present, which results in aggravation of low-temperature corrosion (acid dew point corrosion), especially when the boiler is operated under low load.
In order to alleviate the problem of air preheater blockage, the air preheater of a plurality of coal-fired units is provided with a hot air recirculation system at present, and two common modes are as follows: one is to introduce hot air to the inlet of the blower or primary fan for blending with cold air, and the other is to separate an independent small-angle hot air recirculation sub-bin (the sub-bin angle is not more than 15 degrees, and hot air independently flows through the heat storage element and is not blended with cold air). However, no matter which way is adopted, the smoke exhaust temperature of the whole smoke side can be only slightly increased, and the smoke temperature is limited by various operation parameters, wherein the smoke temperature increasing range is generally not more than 25 ℃, the smoke temperature increasing range is effective in relieving the problems of low-temperature corrosion and blockage caused by sulfuric acid, the treatment effect on the problem of air preheater blockage caused by ammonium bisulfate is not obvious, and even the problem of air preheater blockage caused by upward movement of ammonium bisulfate deposition is unfavorable for solving the problem of air preheater blockage (see boiler technology, analysis of the influence of circulating wind on the performance and the ash blockage of a rotary air preheater by setting up in the 6 th period of volume 49 of 11 in 2018).
Disclosure of Invention
The invention provides a method and a system for controlling temperature rise and blockage in a split ring of a rotary air preheater, which aim to solve the problem of blockage of a heat storage element in the rotary air preheater in the prior art.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
the rotary air preheater comprises a flue gas sub-bin and at least one air sub-bin, wherein the end face of the cold end of a rotor of the air preheater is divided into N concentric rings by an annular partition plate, N is more than or equal to 2, hot air is introduced into each concentric ring wheel corresponding to the cold end of the at least one air sub-bin to form a hot air curtain, the resistance of cold air entering the corresponding concentric ring is increased, and the wall temperature of a heat storage element in the corresponding concentric ring is increased, so that the anti-blocking effect is realized; and the area where hot air is introduced circumferentially covers 90-165 degrees of central angle of the air sub-bin at the cold end face of the air preheater rotor.
According to the technical scheme, the hot air is introduced to form the hot air curtain, the cold air inlet amount is reduced, meanwhile, the hot air is introduced, the temperature of the corresponding circulating air is increased, the wall temperature of the corresponding heat storage element in the concentric ring is obviously increased, and the heat storage element is heated for a long time when the rotor of the air preheater rotates for every circle due to the large enough angle of the air division covered by the hot air, so that the temperature of the local heat storage element can be greatly increased by periodically utilizing small heat (carried by circulating hot air) on the premise of not affecting the normal operation of a unit, namely, the corresponding local smoke exhaust temperature is greatly increased, the temperature increasing range can reach more than 50 ℃, thereby not only gasifying sulfuric acid which causes ash blocking, but also gasifying ammonium bisulfate which causes ash blocking of the heat storage element of the air preheater, and the ash blocking problem of the heat storage element of the air preheater can be more thoroughly solved.
The wall temperature of the heat storage element in the corresponding concentric ring rises, and condensed or crystallized substances adhered to the heat storage element gradually gasify and are discharged out of the heat exchanger rotor along with the heat medium, so that the problems of blockage and corrosion of the rotary heat exchanger are effectively solved.
According to the method, the split-ring cold air door is not required to be arranged, the effects of controlling the cold air inlet amount, the temperature and the like in each concentric ring can be achieved, the cost is saved, the installation space is saved, and mechanical faults possibly existing in the split-ring cold air door are avoided.
In order to further increase the temperature rising range of the split ring of the air preheater, the included angle between the flowing direction of hot air and the flowing direction of cold air in the corresponding concentric ring is not less than 90 ℃, downward hot air is used for blocking upward cold air, so that the resistance of cold air entering can be further increased, the amount of doped cold air is reduced as much as possible, the total air quantity flowing in the corresponding ring is reduced, and meanwhile, the temperature of the corresponding circulating ventilation air is increased.
The hot air area is defined as the area of the cold end face of the air preheater rotor, corresponding arc-shaped air supply channels are arranged below the concentric ring hot air areas for raising the temperature of the split rings of the air preheater, and hot air is introduced into the corresponding arc-shaped air supply channels to form a hot air curtain.
The cross section of the outlet end of the arc-shaped air supply channel is in an arc shape matched with the concentric rings corresponding to the hot air areas, namely, the upper end face (outlet end) of the arc-shaped air supply channel is in a fan-shaped mouth structure comprising two arc-shaped edges, and the two arc-shaped edges of the arc-shaped air supply channel are equal to the radian of the annular partition plates on the two sides of the concentric rings corresponding to the hot air areas and are opposite up and down. The outlet end of the arc-shaped air supply channel is opposite to the concentric ring of the hot air area.
The fan-shaped structure comprises two arcs with the same bending direction and a pattern surrounded by two radial edges connecting two ends of the two arcs.
The conventional thinking is that the split-ring cold air door is required to be installed on the arc-shaped air supply channel to control the cold air inflow of the corresponding area, but the conventional thinking is broken through, the split-ring cold air door is not arranged, and the cold air inflow of the corresponding area is controlled through the hot air curtain, so that the wall temperature of the thermal element is improved, the anti-blocking effect is achieved, the installation structure is simplified, the control is simplified, the effect is better and more obvious, and the cost is low.
In order to further raise the temperature rise range of the split ring of the air preheater, each arc-shaped air supply channel is internally provided with a circumferential flow equalizing device, hot air is introduced into the circumferential flow equalizing device, and then flows out of the circumferential flow equalizing device in a direction with an included angle of not less than 90 ℃ with the cold air flowing direction in the corresponding concentric ring, and a hot air curtain is formed in the arc-shaped air supply channel. The circumferential flow equalizing device enables circulating hot air to be uniformly distributed in the arc-shaped air supply channel as much as possible, and the hot air is mixed with cold air in the fan-shaped ring area of the cold end and then flows through the heat storage element.
As a specific implementation scheme, the circumferential flow equalization device comprises an upper shell and a lower shell, wherein the upper shell and the lower shell are of cavity structures with end capped at the top and opened at the bottom, the top of the lower shell stretches into the upper shell from the bottom of the upper shell, a space is reserved between the side wall of the upper shell and the side wall of the lower shell, and hot air is introduced into the upper shell, overflows from the space between the upper shell and the lower shell and forms a hot air curtain; the upper shell is connected to the air preheater stator through a connecting piece, the lower shell is connected to the upper shell through a connecting piece and/or the lower shell is connected to the air preheater stator through a connecting piece. The form of the connecting piece is not limited in the application, and can be in a rod shape, a sheet shape and the like, and bolts, nuts and the like which are necessary for connection are included.
An air preheater is a rotating device comprising a rotor and a stator, wherein the stator is a broad concept and non-rotating parts all count on the stator.
The cross sections of the upper shell and the lower shell are arc-shaped matched with the concentric rings, the upper shell and the lower shell are arranged along the circumferential direction of the hot air area, and the arc edges of the concentric rings on which the upper shell and the lower shell are circumferentially arranged are parallel to each other; the upper shell is vertically arranged along two side walls of the circumferential direction, and the lower shell is in a horn shape with gradually increased openings from top to bottom along the two side walls of the circumferential direction.
Further preferably, the included angle between the side walls of the two sides of the lower shell along the circumferential direction and the vertical direction is 0-80 degrees.
In order to improve stability, the device also comprises a connecting column, wherein the top of the connecting column is connected with the inner top of the upper shell, and the bottom of the connecting column is connected with the outer top of the lower shell. The spliced pole can be followed circumference and set up many, namely will go up casing and lower casing and link together through the spliced pole that sets up along circumference to improve stability, the quantity of spliced pole can be confirmed according to the scene operating mode, in order to guarantee hot-blast transportation stability and be accurate.
The hot air is preferably hot air or hot air derived from the rotary air preheater itself.
For the three-bin or four-bin air preheater, the air preheater further comprises a circulating hot air pipe, preferably, the hot air is hot primary air, the arc-shaped air supply channel is arranged below the cold end of the secondary air bin, one end of the circulating hot air pipe is connected with a hot primary air outlet air channel, the other end of the circulating hot air pipe is branched into N circulating branch pipes, the circulating branch pipes are equal in number to the arc-shaped air supply channels and correspond to the arc-shaped air supply channels one by one, at least one set of circulating hot air door is arranged on each circulating branch pipe, self-flow is realized by utilizing the differential pressure of the hot primary air and the cold secondary air, and hot air recycling is realized by round-round inspection regulation of the circulating hot air door.
For the two-compartment air preheater, the air preheater also comprises a circulating hot air pipe, preferably, the hot air is air compartment outlet hot air, the arc-shaped air supply channel is arranged at the lower part of the cold end of the air compartment, one end of the circulating hot air pipe is connected with the air compartment outlet air channel, the other end of the circulating hot air pipe is branched into N circulating branched pipes, the quantity of the circulating branched pipes is equal to that of the arc-shaped air supply channels and corresponds to that of the arc-shaped air supply channels one by one, the circulation branch pipes are led into the corresponding arc-shaped air supply channels, each circulation branch pipe is provided with at least one set of circulation hot air door, the circulation hot air pipe is provided with a hot air recirculation fan, and the hot air recycling of each ring of wheels is realized by the wheel inspection adjustment of the circulating hot air door under the suction effect of the hot air recycling fan.
The circulating hot air door and the recirculating fan are arranged outside the air preheater.
The rotary air preheater comprises a flue gas sub-bin and at least one air sub-bin, wherein the end face of the cold end of the air preheater rotor is divided into N concentric rings by an annular partition plate, N is more than or equal to 2, the end face of the cold end of the air preheater rotor is provided with a hot air zone, the hot air zone at least covers an angle corresponding to the complete air sub-bin, and the central angle of the hot air zone is 90-165 degrees; corresponding arc-shaped air supply channels are arranged below the concentric rings of the hot air area.
In order to improve uniformity and anti-blocking effect, all be equipped with circumference flow straightener in each arc air supply passageway.
As a specific implementation scheme, the circumferential flow equalization device comprises an upper shell and a lower shell, wherein the upper shell and the lower shell are of cavity structures with end capped at the top and opened at the bottom, the top of the lower shell stretches into the upper shell from the bottom of the upper shell, a space is reserved between the side wall of the upper shell and the side wall of the lower shell, and hot air is introduced into the upper shell, overflows from the space between the upper shell and the lower shell and forms a hot air curtain; the upper shell is connected to the air preheater stator through a connecting piece, the lower shell is connected to the upper shell through a connecting piece and/or the lower shell is connected to the air preheater stator through a connecting piece.
The cross sections of the upper shell and the lower shell are arc-shaped matched with the concentric rings, namely the upper shell and the lower shell are arranged along the circumference of the hot air area, and the arc edges of the upper shell and the lower shell, which are circumferentially arranged on the concentric rings, are mutually parallel.
In order to promote anti-blocking effect, go up the both sides wall of casing along circumference (the circumference lateral wall of going up the casing, go up the casing and include two circumference lateral walls, establish the end lateral wall and the fixed side wall at circumference lateral wall both ends, also go up the casing and be the box body structure of opening decurrent promptly), the both sides wall of casing along circumference down (the circumference lateral wall of going up the casing, go up the casing and include two circumference lateral walls, establish the end lateral wall and the fixed side wall at circumference lateral wall both ends, also go up the casing and be the decurrent box body structure of opening promptly) be from the top down and be the tubaeform that the opening increases gradually.
Further preferably, the included angle between the two side walls of the lower shell along the circumferential direction and the vertical direction is 0-80 degrees.
In order to improve stability, the device also comprises a connecting column, wherein the top of the connecting column is connected with the inner top of the upper shell, and the bottom of the connecting column is connected with the outer top of the lower shell. The spliced pole can be followed circumference and set up many, namely will go up casing and lower casing and link together through the spliced pole that sets up along circumference to improve stability, the quantity of spliced pole can be confirmed according to the scene operating mode, in order to guarantee hot-blast transportation stability and be accurate.
For the three-bin or four-bin air preheater, the air preheater further comprises a circulating hot air pipe, preferably, the hot air is hot primary air, the arc-shaped air supply channel is arranged below the cold end of the secondary air bin, one end of the circulating hot air pipe is connected with a hot primary air outlet air channel, the other end of the circulating hot air pipe is branched into N circulating branch pipes, the circulating branch pipes are equal in number to the arc-shaped air supply channels and correspond to the arc-shaped air supply channels one by one, at least one set of circulating hot air door is arranged on each circulating branch pipe, self-flow is realized by utilizing the differential pressure of the hot primary air and the cold secondary air, and hot air recycling is realized by round-round inspection regulation of the circulating hot air door.
For the two-compartment air preheater, the air preheater also comprises a circulating hot air pipe, preferably, the hot air is air compartment outlet hot air, the arc-shaped air supply channel is arranged at the lower part of the cold end of the air compartment, one end of the circulating hot air pipe is connected with the air compartment outlet air channel, the other end of the circulating hot air pipe is branched into N circulating branched pipes, the quantity of the circulating branched pipes is equal to that of the arc-shaped air supply channels and corresponds to that of the arc-shaped air supply channels one by one, the circulation branch pipes are led into the corresponding arc-shaped air supply channels, each circulation branch pipe is provided with at least one set of circulation hot air door, the circulation hot air pipe is provided with a hot air recirculation fan, and the hot air recycling of each ring of wheels is realized by the wheel inspection adjustment of the circulating hot air door under the suction effect of the hot air recycling fan.
The technology not mentioned in the present invention refers to the prior art.
According to the annular heating blocking-up control method and system for the rotary air preheater, hot air is introduced into each concentric annular wheel corresponding to the cold end of at least one air sub-bin to form a hot air curtain, resistance to cold air entering in the corresponding concentric annular is increased, wall temperature of a heat storage element in the corresponding concentric annular is increased, blocking-up is realized, and the heat storage element is heated for a long enough time when the air preheater rotor rotates for every circle due to the fact that the angle of the air sub-bin covered by the hot air is large enough, so that the temperature of the local heat storage element can be greatly increased by periodically utilizing a smaller heat time-sharing wheel on the premise that normal operation of a machine set is not influenced, namely, the corresponding local smoke exhaust temperature is greatly increased, the temperature-increasing range can reach more than 50 ℃, and therefore, not only sulfuric acid which causes blocking up ash can be gasified, but also ammonium bisulfate which causes blocking up ash of the heat storage element of the air preheater can be more thoroughly solved; the effects of controlling the cold air inlet amount, the temperature and the like in each concentric ring can be achieved without installing the split ring cold air door, the cost is saved, the installation space is saved, and the possible mechanical faults of the split ring cold air door are avoided.
Drawings
Fig. 1 is a schematic diagram (n=3) of a ring-separating temperature-rising blocking-treating system of a rotary air preheater.
FIG. 2 is a view from direction A-A in FIG. 1 (two-compartment air preheater);
FIG. 3 is a view from direction A-A in FIG. 1 (three-compartment air preheater);
FIG. 4 is a schematic view of the sealing engagement of the annular partition with the outlet end of the arcuate air supply passage of the present invention;
fig. 5 is a schematic diagram (n=2) of a ring-separating temperature-rising blocking-treating system of the rotary air preheater.
FIG. 6 is a view from direction A-A in FIG. 5 (two-compartment air preheater);
FIG. 7 is a view from direction A-A of FIG. 5 (three-compartment air preheater);
FIG. 8 is a schematic cross-sectional view of an arcuate air supply channel (including connecting posts);
in the figure: the air flow guide device comprises an annular partition plate 1, a sealing plate 11, an arc-shaped air supply channel 2, an arc-shaped air supply channel outlet end 21, a sealing surface 22, a circumferential flow equalizing device 3, an upper shell 31, a lower shell 32, a connecting column 33, a circulating hot air pipe 4, a circulating branch pipe 41, a circulating hot air door 42, a flue gas sub-bin 5, an air sub-bin 6, a primary air sub-bin 7, a secondary air sub-bin 8, a temperature measuring point 9, a hot air recirculating fan 10 and a medium flow direction indicated by an arrow.
Detailed Description
For a better understanding of the present invention, the following examples are further illustrated, but are not limited to the following examples.
The terms top, bottom, up and down and the like in the present application are based on the relative positional relationships shown in fig. 1 and 5, and should not be construed as absolute limitations of the present application.
Example 1
As shown in fig. 1-2, the rotary air preheater is of a two-compartment structure and comprises a flue gas compartment and an air compartment, the end face of the cold end of the air preheater rotor is divided into 3 concentric rings by an annular partition plate, hot air is introduced into each concentric ring wheel corresponding to the cold end of at least one air compartment to form a hot air curtain, resistance of cold air entering the corresponding concentric ring is increased, and wall temperature of a heat storage element in the corresponding concentric ring is increased, so that anti-blocking is realized; the area of hot air inlet covers the whole air sub-bin (about 165 degrees) of the cold end face of the air preheater rotor in the circumferential direction.
According to the technical scheme, hot air is introduced to form a hot air curtain, the cold air entering amount is reduced, meanwhile, hot air is introduced, the temperature of corresponding circulating air is increased, the wall temperature of corresponding heat storage elements in the concentric rings is obviously increased, and the heat storage elements are heated for a long time when the rotor of the air preheater rotates for a circle due to the fact that the air division angle covered by the hot air is large enough, so that the temperature of the local heat storage elements can be greatly increased by periodically utilizing small heat (carried by circulating hot air) on the premise of not affecting the normal operation of a unit, namely, the temperature corresponding to local smoke discharging temperature is greatly increased, the temperature increasing range can reach more than 50 ℃, and therefore, not only sulfuric acid which is blocked by ash can be gasified, but also ammonium bisulfate which is blocked by ash can be gasified, and the ash blocking problem of the heat storage elements of the air preheater is more thoroughly solved.
Example 2
On the basis of example 1, the following modifications were further made: in order to further increase the temperature rising range of the split ring of the air preheater, as shown in fig. 1, the included angle between the flowing direction of hot air and the flowing direction of cold air in the corresponding concentric ring is not less than 90 ℃, downward hot air is used for blocking upward cold air, so that the resistance of cold air entering can be further increased, the amount of cold air doped can be reduced as much as possible, the total air quantity flowing in the corresponding ring is reduced, and the temperature of the corresponding circulating ventilation air is increased.
Example 3
The rotary air preheater is of a two-compartment structure and comprises a flue gas compartment and an air compartment, the cold end face of the air preheater rotor is divided into 3 concentric rings by an annular partition plate, a hot air area is arranged on the cold end face of the air preheater rotor, and the hot air area completely covers the angle corresponding to the air compartment; corresponding arc-shaped air supply channels are arranged below the concentric rings of the hot air area. The cross section of the outlet end of the arc-shaped air supply channel is an arc matched with the corresponding concentric ring hot air area, namely, the upper end face (outlet end) of the arc-shaped air supply channel is of a fan-shaped mouth structure comprising two arc edges, the two arc edges of the arc-shaped air supply channel are equal to and vertically opposite to the radian of the annular partition plates on the two sides of the corresponding hot air area concentric ring, as shown in fig. 4, a sealing assembly is arranged between the outlet end of the arc-shaped air supply channel and the two arc edges (annular partition plates) of the corresponding hot air area concentric ring, and the sealing assembly comprises sealing sheets arranged on the two arc edges (annular partition plates) of the corresponding hot air area concentric ring and sealing surfaces arranged on the two arc edges of the outlet end of the arc-shaped air supply channel.
That is, on the basis of example 2, this example was further modified as follows: the lower part of each concentric ring hot air area is provided with a corresponding arc-shaped air supply channel, and hot air is introduced into the corresponding arc-shaped air supply channel to form a hot air curtain.
Example 4
On the basis of example 3, the following modifications were further made: in order to further raise the temperature rise range of the split ring of the air preheater, each arc-shaped air supply channel is internally provided with a circumferential flow equalizing device, hot air is introduced into the circumferential flow equalizing device, and then flows out of the circumferential flow equalizing device in a direction with an included angle of not less than 90 ℃ with the cold air flowing direction in the corresponding concentric ring, and a hot air curtain is formed in the arc-shaped air supply channel. The circumferential flow equalizing device enables circulating hot air to be uniformly distributed in the arc-shaped air supply channel as much as possible, and the hot air is mixed with cold air in the fan-shaped ring area of the cold end and then flows through the heat storage element.
Example 5
On the basis of example 4, the following modifications were further made: as shown in fig. 1, the circumferential flow equalizing device comprises an upper shell and a lower shell, wherein the upper shell and the lower shell are of cavity structures with end capped at the top and open at the bottom, the top of the lower shell extends into the upper shell from the bottom of the upper shell, a space is reserved between the side wall of the upper shell and the side wall of the lower shell, and hot air is introduced into the upper shell, overflows from the space between the upper shell and the lower shell, and a hot air curtain is formed; the upper shell is connected to the air preheater stator through a connecting piece, the lower shell is connected to the upper shell through a connecting piece and/or the lower shell is connected to the air preheater stator through a connecting piece.
As shown in fig. 2, the cross sections of the upper shell and the lower shell are arc-shaped matched with the concentric rings, the upper shell and the lower shell are arranged along the circumferential direction of the hot air area, and the arc edges of the concentric rings on which the upper shell and the lower shell are arranged are parallel to each other in the circumferential direction; the upper shell is vertically arranged along two side walls of the circumferential direction, and the lower shell is in a horn shape with gradually increased openings from top to bottom along the two side walls of the circumferential direction. In this example, the included angle between the two side walls of the lower shell along the circumferential direction and the vertical direction is 30 ° (proved by practice, the included angle can also be set to 10 °,20 °, 45 °, 60 ° and the like, the resistance formed by different angles is different, and is determined specifically according to the heating amplitude required by anti-blocking under the actual working condition), hot air is introduced into the upper shell, overflows from the interval between the upper shell and the lower shell, a hot air curtain is formed, and the included angle between the flowing direction of the hot air curtain and the flowing direction of cold air in the corresponding concentric ring is about 150 °.
As shown in fig. 1-2, temperature measuring points are distributed below the flue gas sub-bins corresponding to the concentric rings, so that the lifting amplitude of the wall temperature of the heat storage element in the corresponding concentric ring is sensed in real time.
Example 6
On the basis of example 5, the following modifications were further made: as shown in fig. 8, in order to improve stability, 3 connecting columns are further included, the top of which is connected with the inner top of the upper housing, and the bottom of which is connected with the outer top of the lower housing. The 3 connecting columns are distributed along the circumferential direction.
Example 7
On the basis of examples 5 or 6, the following modifications were further made: as shown in fig. 1-2, the air conditioner further comprises a circulating hot air pipe, the hot air is air-separating cabin outlet hot air, the arc-shaped air supply channel is arranged at the lower part of the cold end of the air separating cabin, one end of the circulating hot air pipe is connected with the air-separating cabin outlet air channel, the other end of the circulating hot air pipe is branched into 3 circulating branch pipes, the number of the circulating branch pipes is equal to that of the arc-shaped air supply channels and corresponds to that of the arc-shaped air supply channels one by one, each circulating branch pipe is provided with a set of circulating hot air door, the circulating hot air pipe is provided with a hot air recirculation fan, and the circulating hot air recirculation of each ring is realized through the round inspection adjustment of the circulating hot air door by utilizing the suction effect of the hot air recirculation fan.
Example 8
Unlike example 7, the following is: as shown in fig. 4, the rotary air preheater is of a three-branch bin structure and comprises a flue gas branch bin, a primary air branch bin and a secondary air branch bin, hot air is hot primary air, a hot air area completely covers the corresponding angle (about 110 degrees) of the secondary air branch bin, an arc-shaped air supply channel is arranged below the cold end of the secondary air branch bin, one end of a circulating hot air pipe is connected with a hot primary air outlet air channel, the other end of the circulating hot air pipe is branched into 3 circulating branch pipes, the circulating branch pipes are equal in number and in one-to-one correspondence with the arc-shaped air supply channels, the circulating branch pipes are led into the corresponding arc-shaped air supply channels, a set of circulating hot air door is arranged on each circulating branch pipe, self-flow is realized by utilizing the differential pressure of the hot primary air and the cold secondary air, and hot air recycling of each ring is realized by wheel inspection adjustment of the circulating hot air door.
Example 9
Unlike example 7, the following is: as shown in fig. 5-6, the cold end face of the air preheater rotor is divided into 2 concentric rings by an annular partition plate, two corresponding circumferential flow equalizers and circulation branch pipes are also provided, and the rest of the structure is referred to in embodiment 7.
Example 10
Unlike example 9, the following is: as shown in fig. 7, the rotary air preheater is of a three-branch bin structure and comprises a flue gas branch bin, a primary air branch bin and a secondary air branch bin, hot air is hot primary air, a hot air area completely covers the corresponding angle (about 110 degrees) of the secondary air branch bin, an arc-shaped air supply channel is arranged below the cold end of the secondary air branch bin, one end of a circulating hot air pipe is connected with a hot primary air outlet air channel, the other end of the circulating hot air pipe is branched into 2 circulating branch pipes, the circulating branch pipes are equal in number and in one-to-one correspondence with the arc-shaped air supply channels, the circulating branch pipes are led into the corresponding arc-shaped air supply channels, a set of circulating hot air door is arranged on each circulating branch pipe, self-flow is realized by utilizing the differential pressure of the hot primary air and the cold secondary air, and hot air recycling of each ring is realized by wheel inspection adjustment of the circulating hot air door.
According to the method and the system for controlling the temperature rise and blockage of the rotary air preheater by ring division, hot air is introduced into each concentric ring wheel corresponding to the cold end of at least one air sub-bin to form a hot air curtain, resistance to cold air entering into the corresponding concentric ring is increased, wall temperature of a heat storage element in the corresponding concentric ring is increased, the blockage prevention is realized, and the heat storage element is heated for a long enough time when an air preheater rotor rotates for one circle due to the large enough angle of the air sub-bin covered by the hot air, so that the temperature of the local heat storage element is greatly increased by using smaller heat (about 5% of total air supply of a boiler) every 20-30 days on the premise that normal operation of a unit is not influenced, namely, the temperature of the local heat storage element is greatly increased corresponding to local smoke discharge temperature, the temperature increasing range can reach more than 50 ℃ (the smoke temperature reaches more than 180 ℃), and the ash blocking problem of the heat storage element of the air preheater can be gasified; the effects of controlling the cold air inlet amount, the temperature and the like in each concentric ring can be achieved without installing the split ring cold air door, the cost is saved, the installation space is saved, and the possible mechanical faults of the split ring cold air door are avoided.

Claims (10)

1. The utility model provides a rotary air preheater divides ring intensification to block up method, rotary air preheater includes flue gas divides storehouse and at least one air divides storehouse, its characterized in that: the end face of the cold end of the air preheater rotor is divided into N concentric rings by an annular partition plate, N is more than or equal to 2, hot air is introduced into each concentric ring wheel corresponding to the cold end of at least one air sub-bin to form a hot air curtain, the resistance of cold air entering the corresponding concentric ring is increased, and the wall temperature of a heat storage element in the corresponding concentric ring is increased, so that anti-blocking is realized; and the area where hot air is introduced circumferentially covers 90-165 degrees of central angle of the air sub-bin at the cold end face of the air preheater rotor.
2. The method for controlling the temperature rise and blockage of the rotary air preheater by ring separation is characterized in that: the included angle between the flowing direction of the hot air and the flowing direction of the cold air in the corresponding concentric ring is not less than 90 ℃.
3. The method for controlling the temperature rise and blockage of the rotary air preheater by separating rings is characterized in that: the hot air inlet area of the cold end face of the air preheater rotor is defined as a hot air area, and corresponding arc-shaped air supply channels are arranged below the hot air areas of the concentric rings, and hot air is introduced into the corresponding arc-shaped air supply channels to form a hot air curtain.
4. The method for controlling the temperature rise and blockage of the rotary air preheater by separating rings is characterized in that: and each arc-shaped air supply channel is internally provided with a circumferential flow equalizing device, hot air is introduced into the circumferential flow equalizing devices, and then flows out of the circumferential flow equalizing devices in a direction with an included angle of not less than 90 ℃ with the cold air flowing direction in the corresponding concentric ring, so that a hot air curtain is formed in the arc-shaped air supply channel.
5. The utility model provides a stifled system is treated in annular heating of rotation air preheater divides, rotation air preheater includes flue gas divides storehouse and at least one air divides storehouse, its characterized in that: the cold end face of the air preheater rotor is divided into N concentric rings by an annular partition plate, N is more than or equal to 2, a hot air area is arranged on the cold end face of the air preheater rotor, the hot air area at least covers an angle corresponding to a complete air sub-bin, and the central angle of the hot air area is 90-165 degrees; corresponding arc-shaped air supply channels are arranged below the concentric rings of the hot air area.
6. The rotary air preheater split-ring heating plugging control system as set forth in claim 5, wherein: and each arc-shaped air supply channel is internally provided with a circumferential flow equalizing device.
7. The rotary air preheater split-ring heating plugging control system as set forth in claim 6, wherein: the circumferential flow equalizing device comprises an upper shell and a lower shell, wherein the upper shell and the lower shell are of cavity structures with end capped at the top and open at the bottom, the top of the lower shell extends into the upper shell from the bottom of the upper shell, a space is reserved between the side wall of the upper shell and the side wall of the lower shell, and hot air is introduced into the upper shell, overflows from the space between the upper shell and the lower shell and forms a hot air curtain; the upper shell is connected to the air preheater stator through a connecting piece, the lower shell is connected to the upper shell through a connecting piece and/or the lower shell is connected to the air preheater stator through a connecting piece.
8. The rotary air preheater split-ring heating plugging control system as set forth in claim 12, wherein: the circumferential flow equalization device also comprises a connecting column; the cross sections of the upper shell and the lower shell are arc-shaped matched with concentric rings; the two side walls of the upper shell along the circumferential direction are vertically arranged, and the two side walls of the lower shell along the circumferential direction are in a horn shape with gradually increased openings from top to bottom; the included angle between the two side walls of the lower shell along the circumferential direction and the vertical direction is 0-80 degrees; the top of the connecting column is connected with the inner top of the upper shell, and the bottom of the connecting column is connected with the outer top of the lower shell.
9. The rotary air preheater split-ring heating plugging control system as set forth in any one of claims 5-8, wherein: for the three-branch bin or the four-branch bin air preheater, the circulating hot air pipe is hot primary air, the arc air supply channel is arranged below the cold end of the secondary air branch bin, one end of the circulating hot air pipe is connected with a hot primary air outlet air channel, the other end of the circulating hot air pipe is branched into N circulating branch pipes, the quantity of the circulating branch pipes is equal to that of the arc air supply channels and corresponds to that of the arc air supply channels one by one, at least one set of circulating hot air door is arranged on each circulating branch pipe, the self-flow is realized by utilizing the differential pressure of the hot primary air and the cold secondary air, and the hot air recirculation is realized by the round inspection regulation of the circulating hot air door.
10. The rotary air preheater split-ring heating plugging control system as set forth in any one of claims 5-8, wherein: to two sub-storehouse air pre-heaters, still include the circulation hot-blast pipe, hot-blast air is air sub-storehouse export hot-blast, arc air supply channel establishes in air sub-storehouse cold junction lower part, the air sub-storehouse export wind channel is connected to circulation hot-blast pipe one end, the other end branch is N circulation bleeder, the quantity of circulation bleeder and arc air supply channel equals, and the one-to-one, the circulation bleeder lets in the arc air supply channel that corresponds, be equipped with one set of circulation hot air door on every circulation bleeder at least, set up hot air recirculation fan on the circulation hot-blast pipe, utilize hot air recirculation fan's suction effect, the round of through circulation hot air door is patrolled and is adjusted and is realized every round and patrol hot air recirculation.
CN202311647357.4A 2023-12-04 2023-12-04 Method and system for ring-division heating and blocking-treatment of rotary air preheater Withdrawn CN117663177A (en)

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CN202311647357.4A CN117663177A (en) 2023-12-04 2023-12-04 Method and system for ring-division heating and blocking-treatment of rotary air preheater
CN202410336345.8A CN118208744A (en) 2023-12-04 2024-03-22 Method and system for ring-division heating and blocking-treatment of rotary air preheater

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CN202311647357.4A CN117663177A (en) 2023-12-04 2023-12-04 Method and system for ring-division heating and blocking-treatment of rotary air preheater

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CN202410336345.8A Pending CN118208744A (en) 2023-12-04 2024-03-22 Method and system for ring-division heating and blocking-treatment of rotary air preheater

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