CN111412489A - Plate-type air preheater for coal-fired boiler - Google Patents
Plate-type air preheater for coal-fired boiler Download PDFInfo
- Publication number
- CN111412489A CN111412489A CN202010437293.5A CN202010437293A CN111412489A CN 111412489 A CN111412489 A CN 111412489A CN 202010437293 A CN202010437293 A CN 202010437293A CN 111412489 A CN111412489 A CN 111412489A
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- China
- Prior art keywords
- flue gas
- plate
- air
- heat transfer
- fired boiler
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Classifications
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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
- F23L15/04—Arrangements of recuperators
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D9/00—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
- F28D9/0062—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for one heat-exchange medium being formed by spaced plates with inserted elements
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- 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
Abstract
The invention discloses a plate-type air preheater for a coal-fired boiler, which comprises a plurality of heat transfer plates (1) which are arranged in parallel in the vertical direction, wherein flue gas blocking plates (7) are arranged on the left side and the right side of each two adjacent heat transfer plates (1), a flue gas channel (4) is formed between each flue gas blocking plate (7) and each two adjacent heat transfer plates (1), air blocking plates (8) are arranged on the upper side and the lower side of each two adjacent heat transfer plates (1), an air channel (6) is formed between each air blocking plate (8) and each two adjacent heat transfer plates (1), and the air channels (6) and the flue gas channels (4) are arranged at intervals, so that air and flue gas can flow in. The invention has reliable wear-resistant and dust-deposition-resistant capabilities.
Description
Technical Field
The invention belongs to the technical field of heat exchangers, and particularly relates to a plate-type air preheater for a coal-fired boiler, which is suitable for flue gas-air heat exchange on the coal-fired boiler.
Background
The air preheater is a device for recovering the waste heat of flue gas of power station boilers and various industrial furnaces, and has wide application in industry. At present, a coal-fired boiler mainly adopts a tubular or rotary air preheater, the tubular air preheater has a simple structure and lower cost, but has the defects of large volume, and is mainly applied to boilers of generator sets of 200WM and below. The boilers of the generator sets with the power of 300MW and above are basically all rotary air preheaters. The rotary air preheater has compact structure and higher heat transfer efficiency, but has the defect of overlarge air leakage rate. With the gradual increase of the energy-saving and emission-reducing pressure of the coal-fired generator set, the air leakage problem of the rotary air preheater becomes non-negligible, and various measures are taken, but due to inherent disadvantages in the structure, the air leakage problem of the rotary air preheater can only be reduced as much as possible and cannot be eliminated. Aiming at the problems that the tubular air pre-heater is too large in size and the rotary air pre-heater is large in air leakage rate, the application of the plate type air pre-heater to the coal-fired power plant boiler becomes a feasible technical scheme. The plate type air preheater and the tubular air preheater can achieve zero air leakage, but the volume of the plate type air preheater is far smaller than that of the tubular air preheater, and the plate type air preheater has the potential of replacing a rotary air preheater used on a large boiler.
The plate preheater is formed by welding a plurality of layers of thin plates layer by layer, a proper gap is reserved between every two adjacent layers of plates, and the smoke and the air are respectively transmitted through the adjacent gaps at intervals and are subjected to heat transfer through the thin plates. Fig. 1(a) - (c) are several typical arrangement forms of a plate air preheater, and the flue gas and the air side of the conventional plate air preheater can be designed into a single-flow path or a multi-flow path according to requirements, for example, in fig. 1(a) - (c), the air is respectively a single-flow path, a double-flow path and a three-flow path, and the flue gas adopts a single-flow path. In order to enhance heat transfer and facilitate positioning and supporting between plates, the plates of the conventional plate heat exchanger are mostly made of various profiled steel plates (such as herringbone plates, corrugated plates and the like).
The traditional plate-type air preheater is mainly applied to flue gas waste heat recovery of gas and oil industrial boilers and is formed by welding superposed thin plates. The conventional plate type air preheater mostly adopts a complex compression structure for enhancing heat exchange, and the distance between the plates is mainly supported by the bulges on the backup plate, so that the distance between the flow passage plates is small, the flow passage is complex, and when the plate type air preheater is used for a coal-fired boiler, the problems of ash blockage and abrasion are easily caused due to large ash content in flue gas,
disclosure of Invention
Aiming at the problems of the plate type air preheater applied to the coal-fired boiler, the invention provides a plate type air preheater for the coal-fired boiler, which has reliable wear resistance and dust deposition resistance.
The invention is realized by adopting the following technical scheme:
the utility model provides a plate-type air heater for coal fired boiler, includes a plurality of heat transfer plates of parallel arrangement in the vertical direction, and the left and right sides of two adjacent heat transfer plates all is provided with the flue gas closure plate, forms flue gas passageway between flue gas closure plate and two adjacent heat transfer plates, and the upper and lower both sides of two adjacent heat transfer plates all are provided with the air closure plate, forms air passageway (6) between air closure plate and two adjacent heat transfer plates, and air passageway and flue gas passageway interval arrangement for air and flue gas can cross flow.
A further improvement of the invention is that the heat transfer plates are planar light plates.
The further improvement of the invention is that the width Dy of the flue gas flow channel is more than or equal to 0.002 x Hy +20, unit: mm, wherein Hy is the height of the flue gas flow channel.
The invention is further improved in that a plurality of first supporting pieces are arranged in the flue gas flow passage.
The further improvement of the invention is that when the height Hy of the flue gas flow channel is more than or equal to 500mm, a plurality of second supporting pieces are also arranged in the flue gas flow channel, the second supporting pieces are positioned on the first supporting pieces or the central line of the small flow channel formed by the first supporting pieces and the flue gas blocking plate, and the distance Hdz between the second supporting pieces is less than or equal to (-30 × Δ P +1000), unit: mm, Δ P is air, flue gas side pressure difference, unit: kPa;
spacing L z between the first support members is ≦ (-50 × Δ P +1500) in mm.
The invention is further improved in that an anti-abrasion cover plate is arranged above the air blocking plate at the inlet of the flue gas channel.
The invention has the further improvement that the height Hgb of the anti-abrasion cover plate is more than or equal to 1.73 x Dy +50, the insertion depth Hcs of the anti-abrasion cover plate is more than or equal to Dk, wherein Dy is the width of a flue gas flow channel, Dk is the distance between air flow channels, and the unit is as follows: mm.
The invention has at least the following beneficial technical effects:
1. the heat transfer plates of the heat exchanger are all in a smooth surface flat plate structure, and the flue gas is arranged in a single flow from top to bottom;
2. the distance between the side plates of the flue gas (0.002 x Hy +20) is more than or equal to Dy and less than or equal to 50 (mm);
3. when the height Hy of the flue gas side flow channel is more than or equal to 500mm, second supporting pieces need to be added, and the distance Hdz between the second supporting pieces is less than or equal to (-30 × Δ P +1000) (mm) (Δ PkPa is the pressure difference between the air side and the flue gas side).
4. When the width L y of the flue gas side flow channel is more than or equal to 400mm, the first supporting pieces need to be added, and the distance L z between the first supporting pieces is less than or equal to (-50 × Δ P +1500) (mm) (Δ PkPa is the pressure difference of the air and the flue gas side).
5. The first supporting part preferably adopts an I-shaped cross section structure;
6. an n-shaped anti-abrasion cover plate is added at the inlet of the smoke side, the height Hgb of the cover plate is more than or equal to 1.73 x Dy +50(mm), and the insertion depth Hcs of the anti-abrasion cover plate is more than or equal to Dk.
Drawings
Fig. 1 is a schematic structural diagram of a conventional plate air preheater, and air in fig. 1(a) - (c) is respectively a single-flow process, a double-flow process and a three-flow process.
FIG. 2 is a schematic view showing a structure of a plate type air preheater for a coal fired boiler according to the present invention.
Fig. 3 is a view from direction a of fig. 2.
Fig. 4(a) - (d) are cross-sectional exemplary shapes of several first supports, respectively.
Fig. 5 is a view from direction B of fig. 2.
Description of reference numerals:
1 is the heat transfer plate, 2 is the second support piece, 3 is first support piece, 4 is the flue gas passageway, 5 is the abrasionproof apron, 6 is the air passage, 7 is the flue gas closure plate, 8 is the air closure plate.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
As shown in fig. 2 to 4, the plate air preheater for the coal-fired boiler provided by the invention is formed by overlapping and welding a plurality of layers of heat transfer plates 1, wherein the heat transfer plates 1 and a flue gas blocking plate 7 form a flue gas channel 4, the heat transfer plates 1 and an air blocking plate 8 form an air channel 6, the air channel 6 and the flue gas channel 4 are arranged at intervals, air and flue gas flow in a cross way, and heat is transferred through the heat transfer plates 1.
In order to prevent dust accumulation, the heat exchange plate 1 of the invention requires a plane light plate and does not adopt a contour plate. Meanwhile, in order to prevent dust deposition, the smoke side of the heat exchanger adopts a single flow, and the smoke flowing direction from top to bottom is preferably selected. Compared with the conventional plate heat exchanger, the distance Dy between the heat exchange plates of the flue gas flow passage 4 of the plate heat exchanger of the coal-fired boiler needs to be enlarged. Dy is related to the height Hy of the flue gas flow channel, and the larger the Hy is, the larger the Dy is. In the invention, the distance Dy between the heat exchange plates at two sides of the flue gas flow channel 4 is more than or equal to 0.002 x Hy +20(mm), the distance Dy is expanded as much as possible under the condition that other conditions are met, but the maximum value is not more than 50 mm. The air flow channel spacing Dk can be flexibly set according to actual needs.
Because the air side in the boiler air preheater is the positive pressure, the flue gas side is the negative pressure, in order to prevent that the pressure differential from causing flue gas runner 4 to extrude the deformation to arouse the deposition of ash and local wear, need increase second support piece 2 and first support piece 3 in flue gas runner 4, as shown in figure 3.
When the height Hy of the flue gas flow channel is more than or equal to 500mm, the second supporting piece 2 is needed to be added, the second supporting piece 2 is positioned on the central line of the small flow channel formed by the first supporting piece 3 or the first supporting piece 3 and the flue gas blocking plate 7, the distance Hdz between the second supporting pieces 2 is related to the side pressure difference delta P (kPa) of air and flue gas, and Hdz is less than or equal to (-30 x delta P +1000) (mm).
When the width L y of the flue gas flow channel 4 is more than or equal to 400mm, the first supporting pieces 3 need to be added, and the spacing L z between the first supporting pieces 3 is related to the side pressure difference delta P (kPa) of air and flue gas, L z is less than or equal to (-50 x delta P +1500) (mm).
The first supporting member 3 has various forms, and the cross section of the first supporting member 3 of the present invention is preferably in an i shape as shown in fig. 4(a), which not only has high supporting strength, but also can prevent the root of the supporting member from being worn. In some cases, the "I" cross-sectional support members may not be used, and other structural support members may be used as shown in FIG. 4.
In order to prevent the abrasion of the smoke side, the invention adds an anti-abrasion cover plate 5 at the smoke side inlet of the air preheater, and the structure of the anti-abrasion cover plate 5 is shown in figure 5. The anti-abrasion cover plate 5 is used for preventing the heat transfer plate 1 and the air blocking plate 8 from being abraded, the cross section of the anti-abrasion cover plate is close to an n shape, the height Hgb of the anti-abrasion cover plate 5 which has the largest influence on the anti-abrasion effect is related to the width Dy of a flue gas flow passage, and Hgb is more than or equal to 1.73 x Dy +50 (mm). In addition, in order to ensure that the anti-wear cover plate 5 and the heat exchange plate 1 have good parallelism, the insertion depth Hcs of the anti-wear cover plate 5 is required to be more than or equal to Dk.
Claims (7)
1. The utility model provides a plate-type air preheater for coal fired boiler, a serial communication port, including a plurality of heat transfer plates (1) of parallel arrangement in the vertical direction, the left and right sides of two adjacent heat transfer plates (1) all is provided with flue gas closure plate (7), form flue gas passageway (4) between flue gas closure plate (7) and two adjacent heat transfer plates (1), the upper and lower both sides of two adjacent heat transfer plates (1) all are provided with air closure plate (8), form air channel (6) between air closure plate (8) and two adjacent heat transfer plates (1), and air channel (6) and flue gas passageway (4) interval arrangement for air and flue gas can cross flow.
2. A plate air preheater for a coal fired boiler as recited in claim 1, wherein the heat transfer plates (1) are flat plate.
3. A plate air preheater for a coal fired boiler as recited in claim 1, wherein a flue gas flow path width Dy is not less than 0.002 x Hy +20 in unit: mm, wherein Hy is the height of the flue gas flow channel.
4. A plate air preheater for a coal fired boiler as recited in claim 1, characterized in that a plurality of first support members (3) are provided in the flue gas flow path (4).
5. A plate air preheater for a coal-fired boiler according to claim 4, wherein when the height Hy of the flue gas flow passage is greater than or equal to 500mm, a plurality of second supporting members (2) are further provided in the flue gas flow passage (4), the second supporting members (2) are located on the center line of the small flow passage formed by the first supporting members (3) or the first supporting members (3) and the flue gas blocking plate (7), and the interval Hdz between the second supporting members (2) is greater than or equal to (-30 Δ P +1000), unit: mm, Δ P is air, flue gas side pressure difference, unit: kPa;
the spacing L z between the first supports (3) is ≦ (-50 × Δ P +1500) in mm.
6. A plate air preheater for a coal fired boiler as claimed in claim 1, wherein an anti-wear cover plate (5) is provided above the air blocking plate (8) at the inlet of the flue gas channel (4).
7. The plate-type air preheater for coal-fired boiler as recited in claim 6, wherein the height Hgb of the wear-resistant cover plate (5) is not less than 1.73 x Dy +50, and the insertion depth Hcs of the wear-resistant cover plate (5) is not less than Dk, wherein Dy is the width of the flue gas flow channel, Dk is the air flow channel spacing, unit: mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010437293.5A CN111412489A (en) | 2020-05-21 | 2020-05-21 | Plate-type air preheater for coal-fired boiler |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010437293.5A CN111412489A (en) | 2020-05-21 | 2020-05-21 | Plate-type air preheater for coal-fired boiler |
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| Publication Number | Publication Date |
|---|---|
| CN111412489A true CN111412489A (en) | 2020-07-14 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202010437293.5A Pending CN111412489A (en) | 2020-05-21 | 2020-05-21 | Plate-type air preheater for coal-fired boiler |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114738790A (en) * | 2022-05-11 | 2022-07-12 | 内蒙古大板发电有限责任公司 | Thermal power plant's air heater prevents blockking up system |
-
2020
- 2020-05-21 CN CN202010437293.5A patent/CN111412489A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114738790A (en) * | 2022-05-11 | 2022-07-12 | 内蒙古大板发电有限责任公司 | Thermal power plant's air heater prevents blockking up system |
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