A rotary air preheater and its corrugated compensation sealing device

Abstract

The present invention relates to the technical field of operation optimization and energy-saving transformation of coal-fired thermal power units, and specifically to a rotary air preheater and its corrugated compensation sealing device. A corrugated compensation sealing device of a rotary air preheater of the present invention comprises a radial sealing sheet, a cantilever and a corrugated compensation device; one end of the cantilever is fixed to the central tube of the rotary air preheater, and the other end is suspended; the upper part of the cantilever is connected to the radial sealing sheet and the fan-shaped plate for contact sealing, and the lower part is connected to the corresponding air preheater rotor partition plate through the corrugated compensation device; a rotary air preheater of the present invention comprises an air preheater rotor, and the air preheater rotor partition plate of the air preheater rotor is provided with the corrugated compensation sealing device. A rotary air preheater and its corrugated compensation sealing device of the present invention have a simple structure, a reasonable design, safe and controllable operation, and can effectively control the air leakage rate of the rotary air preheater in long-term operation, thereby stably reducing the air leakage rate of the rotary air preheater for a long time.

Description

Technical Field

[0001] The present invention relates to the technical field of operation optimization and energy-saving transformation of coal-fired thermal power units, and specifically to a rotary air preheater and its corrugated compensation sealing device. Background Art

[0002] Rotary air preheaters are widely used in power station boilers due to their large heat transfer area per unit volume and compact layout. However, the rotor of a rotary air preheater will undergo mushroom-shaped deformation during hot operation, resulting in a large air leakage rate of the air preheater, affecting the thermal efficiency of the air preheater and increasing the power consumption of the fan. The existing air leakage control technology for rotary air preheaters is mainly based on the flexible sealing principle, using the toughness of materials or using spring and counterweight devices to enable the radial sealing sheet to adjust its position as the sealing gap changes, so as to achieve the purpose of controlling the air leakage rate. Since the flexible sealing device uses contact sealing, the equipment itself has a large loss during operation, requires frequent maintenance and replacement of spare parts, and its air leakage effect often deteriorates or even worsens as the operation time increases.

[0003] In view of the problem of high air leakage rate during operation of the existing air leakage control technology for rotary air preheaters, it is necessary to develop a new technology to solve the above problems. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention provides a rotary air preheater and its corrugated compensation sealing device, which has a simple structure, reasonable design, safe and controllable operation, can effectively control the air leakage rate during the long-term operation of the rotary air preheater, and thus stably reduce the air leakage rate of the rotary air preheater for a long time.

[0005] The present invention is realized through the following technical solutions:

[0006] A corrugated compensation sealing device for a rotary air preheater includes a radial sealing sheet, a cantilever, and a corrugated compensation device;

[0007] One end of the cantilever is fixed to the central cylinder of the rotary air preheater, and the other end is suspended; the upper part of the cantilever is connected to the radial sealing sheet to contact and seal with the sector plate, and the lower part is connected to the corresponding air preheater rotor partition plate through the corrugated compensation device.

[0008] Further, the corrugated compensation device is fixedly connected to the cantilever and the corresponding air preheater rotor partition plate through bolts and a pressing plate for sealing.

[0009] Further, the radial sealing sheet is fixed to the upper part of the cantilever through bolts, and the installation gap between it and the sector plate is 0.5 - 1.5 mm.

[0010] Further, the suspended end of the cantilever is in sealing cooperation with the peripheral sealing structure of the air preheater rotor; a limiting block is fixedly arranged on the side of the peripheral sealing structure, and the suspended end of the cantilever is supported on the limiting block.

[0011] Further, the corrugated compensation device includes a stainless steel wire mesh skeleton, a silicone rubber skin wrapped outside the stainless steel wire mesh skeleton, and heat insulation cotton and heat insulation filler pressed between the stainless steel wire mesh skeleton and the silicone rubber skin.

[0012] Furthermore, the stainless steel wire mesh skeleton is provided with corrugated folds in the height direction.

[0013] A rotary air preheater includes an air preheater rotor, and the corrugated compensation sealing device as described in any one of the above is arranged on the air preheater rotor partition plate of the air preheater rotor.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects:

[0015] The present invention utilizes the corrugated compensation device to absorb and digest the mushroom-shaped deformation of the air preheater rotor, maintain the position of the cantilever carrying the radial sealing piece fixed, so as to ensure that the position of the radial sealing piece is relatively fixed with respect to the sector plate during actual operation, reduce the radial sealing gap to the lowest level, and achieve the purpose of controlling the air leakage of the air preheater; at the same time, the present invention sets up a sealing functional area composed of a sector plate, a radial sealing piece and a cantilever for directly realizing air leakage control, and a mushroom-shaped deformation compensation area of the air preheater composed of a cantilever, a corrugated compensation device, an air preheater rotor partition plate and an air preheater rotor for absorbing rotor deformation, which can effectively solve the problem of high air leakage rate of the rotary air preheater due to the mushroom-shaped deformation of the rotor. Moreover, the corrugated compensation sealing device has basically no material loss during operation, can maintain a fixed sealing gap and a good air leakage control effect for a long time, and has stable operation.

[0016] Further, when the corrugated compensation device of the present invention is connected to the surrounding structures, it is tightly fixed by using bolts and pressing plates to prevent any possible leakage.

[0017] Further, the corrugated compensation device adopted by the present invention is composed of four layers of materials, namely a silicone rubber skin, a stainless steel wire mesh skeleton, heat insulation cotton and heat insulation filler, which are pressed together to form a rotor deformation compensation material with flexibility, heat insulation and good mechanical properties.

[0018] Further, the present invention absorbs the deformation of the air preheater rotor by using the corrugated extension characteristic by arranging corrugated folds in the height direction of the stainless steel wire mesh skeleton of the cantilever to keep the vertical direction of the cantilever free from external forces. Description of the Drawings

[0019] Figure 1 It is a schematic structural cross-sectional view of the present invention in the embodiment.

[0020] Figure 2 This is a side view of the structure described in the embodiments of the present invention.

[0021] In the figure: radial seal piece 1, sector plate 2, cantilever 3, corrugated compensation device 4, air preheater rotor partition plate 5, air preheater rotor 6. Specific embodiments

[0022] The following further elaborates on the present invention in conjunction with specific embodiments, which is an explanation rather than a limitation of the present invention.

[0023] A corrugated compensation sealing device for a rotary air preheater of the present invention, as Figure 1 and Figure 2 shown, includes a radial seal piece 1 adjacent to the sector plate 2, a cantilever 3 for fixing the radial seal piece 1, and a corrugated compensation device 4 located between the cantilever 3 and the air preheater rotor partition plate 5;

[0024] One end of the cantilever 3 is fixed on the central cylinder of the rotary air preheater, and the other end is suspended. The suspended end is in sealing fit with the peripheral structure of the air preheater rotor 6; it is fixed to the central cylinder through the fixed end and supported on a limiting block fixed to the rotor peripheral sealing structure, so as to maintain the fixation of the radial, axial, and circumferential positions;; the radial seal piece 1 is fixedly connected to the upper part of the cantilever 3 by bolts and is in contact sealing with the sector plate 2; the corrugated compensation device 4 includes a stainless steel wire mesh skeleton provided with corrugated folds in the height direction, a silicone rubber skin wrapped outside the stainless steel wire mesh skeleton, as well as heat preservation cotton and heat insulation filler pressed between the stainless steel wire mesh skeleton and the silicone rubber skin, and it is connected to the lower part of the cantilever 3 by bolts and pressing plates and is connected to the corresponding air preheater rotor partition plate 5.

[0025] The above-mentioned sector plate 2, radial seal piece 1, and cantilever 3 together constitute a sealing functional area for controlling air leakage, which is used to directly control air leakage; the above-mentioned cantilever 3, corrugated compensation device 4, air preheater rotor partition plate 5, and air preheater rotor 6 together constitute an air preheater mushroom-shaped deformation compensation area, which is used to absorb the deformation of the air preheater rotor 6;

[0026] Among them, the sealing functional area for controlling air leakage is similar to the structure of the traditional air preheater seal piece. The difference is that the traditional seal piece is installed on the air preheater rotor partition plate 5 and moves with the deformation of the air preheater rotor 6. In the present invention, the air preheater radial seal piece 1 is installed on a cantilever 3 with a certain rigidity and does not move with the deformation of the air preheater rotor 6. During the rotation of the air preheater, the radial seal piece 1 installed on the cantilever 3 maintains a horizontal height, and the gap with the sector plate 2 is controlled at about 1 mm, which neither causes jamming of the air preheater rotor 6 nor can ensure effective air leakage control.

[0027] Among them, although the mushroom-shaped deformation compensation area of the air preheater does not directly contact the sector plate 2, it is the core component for leakage control. During the hot-state operation of the air preheater rotor 6, mushroom-shaped deformation will occur, and the maximum deformation at the outer distal end can reach 50 mm. In actual operation, most of the air leakage short-circuits from the triangular area at the outer distal end. In the present invention, a corrugated compensation device 4 is provided between the cantilever 3 and the air preheater rotor partition plate 5. When the air preheater rotor 6 undergoes deformation during hot-state operation, the cantilever 3 remains horizontal, and the deformation of the air preheater rotor partition plate 5 gradually increases from the central cylinder to the outer distal end of the rotor, driving the corrugated compensation device 4 to extend in sequence. The corrugated compensation device 4 is used to absorb the deformation of the air preheater rotor 6, maintain the tightness of the radial seal piece 1, and maintain the fixed relative position between the radial seal piece 1 and the sector plate 2 and the minimum seal gap. It should be noted that in order to maintain the integrity of the three-way seal structure, the shape of the corrugated compensation device 4 needs to be in sealing cooperation with the air preheater rotor partition plate 5 and the rotor peripheral seal structure.

[0028] Specifically, as Figure 1 shown, in the corrugated compensation seal device of a rotary air preheater according to the present invention, the distance between the radial seal piece 1 installed on the cantilever 3 and the sector plate 2 is the core parameter affecting the air leakage amount - the seal gap;

[0029] In the conventional air preheater seal device, the radial seal piece 1 is installed on the air preheater rotor partition plate 5, and this seal gap becomes larger as the air preheater rotor 6 deforms, thus increasing the air leakage amount of the air preheater. In the present invention, the cantilever 3 bears the radial seal piece 1, and the rigidity of the cantilever 3 is used to maintain the fixed relative position between the radial seal piece 1 and the sector plate 2, that is, to maintain the lowest seal gap, and the cold and hot state seal gaps are basically unchanged and remain stable under different hot-state operation conditions.

[0030] In the conventional air preheater seal device, the radial seal piece 1 and the air preheater rotor partition plate 5 are rigidly connected by bolts. The deformation of the air preheater rotor 6 directly causes the vertical displacement of the radial seal piece 1, and the seal gap becomes larger. In the present invention, the corrugated compensation device 4 separates the radial seal piece 1 and the air preheater rotor partition plate 5, changing from a rigid connection to a flexible connection. The corrugated extension characteristic is used to absorb the deformation of the air preheater rotor 6, and the cantilever 3 is kept free from external forces in the vertical direction; the corrugated compensation device 4 also serves as an isolation device for the flue gas and the air side, completely avoiding the occurrence of the triangular leakage area.

[0031] When the corrugated compensation seal device of a rotary air preheater according to the present invention works, its principle is:

[0032] (1) Under the cold-state operation condition, the air preheater rotor 6 has no obvious deformation and is in a horizontal position as a whole. The corrugated compensation device 4 reserves a corrugated expansion amount, and the installation gap between the radial seal piece 1 and the sector plate 2 is about 1 mm;

[0033] (2) Under the hot operating condition, after the air preheater rotor 6 is fully heated, the air preheater rotor 6 undergoes a mushroom-shaped deformation. The outer distal end of the rotor droops to form an approximately triangular air leakage area with a maximum height of about 10 - 50 mm. At this time, the outer distal end of the partition plate 5 of the air preheater rotor drives the extension of the outer distal end corrugated compensator 4 as the air preheater rotor 6 droops, blocking the triangular air leakage area and preventing the primary and secondary air from leaking to the flue gas side;

[0034] (3) The cantilever 3 and the radial seal piece 1 remain in a horizontal position both under cold and hot operating conditions. Therefore, the gap between the radial seal piece 1 and the sector plate 2 is fixed at about 1 mm.

[0035] Based on the above device, the present invention also provides a rotary air preheater. During the process of the boiler load change, the extension amount of the corrugated compensator 4 changes accordingly, absorbing the mushroom-shaped deformation of the air preheater rotor 6 and maintaining the position of the cantilever 3 carrying the radial seal piece 1 fixed. In this way, it is ensured that the position of the radial seal piece 1 of the air preheater is fixed relative to the sector plate 2 during actual operation. There is no direct contact and material loss in the whole system, and the system has good reliability, ultimately achieving the purpose of controlling the air leakage of the air preheater.

[0036] The implementation of the present invention only requires local modification of the hot-end radial seal device of the air preheater, constructing a corrugated compensator 4 for compensating the deformation of the air preheater rotor 6, and installing a cantilever 3 for fixing the position of the radial seal piece 1. The transformation investment and risk are small.

Claims

1. A corrugated compensation sealing device for a rotary air preheater, characterized in that, it includes a radial sealing piece (1), a cantilever (3) and a corrugated compensation device (4); One end of the cantilever (3) is fixed to the central cylinder of the rotary air preheater, and the other end is suspended; the upper part of the cantilever (3) is connected to the radial sealing piece (1) to contact and seal with the segment plate (2), and the lower part is connected to the corresponding air preheater rotor partition plate (5) through the corrugated compensation device (4); The corrugated compensation device (4) includes a stainless steel wire mesh skeleton, a silicone rubber skin wrapped outside the stainless steel wire mesh skeleton, and heat preservation cotton and heat insulation filler pressed between the stainless steel wire mesh skeleton and the silicone rubber skin; The stainless steel wire mesh skeleton is provided with corrugated folds in the height direction; the corrugated extension characteristic is used to absorb the deformation of the air preheater rotor and maintain the fixed relative position and the minimum sealing gap between the radial sealing piece (1) and the segment plate (2); The radial sealing piece (1) is fixed to the upper part of the cantilever (3) by bolts, and the installation gap between it and the segment plate (2) is 0.5-1.5 mm.

2. The corrugated compensation sealing device for a rotary air preheater according to claim 1, characterized in that, The corrugated compensation device (4) is fixedly connected to the cantilever (3) and the corresponding air preheater rotor partition plate (5) through bolts and a pressing plate for sealing.

3. The corrugated compensation sealing device for a rotary air preheater according to claim 1, characterized in that, The suspended end of the cantilever (3) is in sealing cooperation with the peripheral sealing structure of the air preheater rotor (6); a limiting block is fixedly arranged on the side of the peripheral sealing structure, and the suspended end of the cantilever (3) is supported on the limiting block.

4. A rotary air preheater, characterized in that, it includes an air preheater rotor (6), and a corrugated compensation sealing device as described in any one of claims 1-3 is arranged on the air preheater rotor partition plate (5) of the air preheater rotor (6).

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