Regular bifurcated flue with anti-abrasion and anti-deposition system

Abstract

The application discloses a regular bifurcated flue with an anti-abrasion and anti-dust system, and the outlet of each of the three bifurcated flues is connected with a low-temperature economizer front flue; the inlet of the second low-temperature economizer front flue is opposite to the second bifurcated flue and the outlet of the second low-temperature economizer front flue; the inlet end of the horizontal turning flue is provided with a flue variable-diameter guiding horizontal guide vane group and the corner is provided with a flue turning vertical guiding vane group; the inlet end of the horizontal three-bifurcated flue is provided with a flue bifurcation vertical guiding vane group, the inlet end of the first and third bifurcated flues is provided with a bifurcated branch flue inlet vertical guiding arc-shaped guide vane group, the outlet end of the second bifurcated flue is provided with a bifurcated branch flue inlet vertical uniform flow guide vane group, the inlet to the outlet of the first bifurcated flue is provided with a first bifurcated branch flue vertical guiding arc-shaped guide vane group, and the inlet to the outlet of the third bifurcated flue is provided with a second bifurcated branch flue vertical guiding arc-shaped guide vane group.

Description

Technical Field

[0001] This invention belongs to the field of anti-wear and anti-ash accumulation technology for low-temperature economizers, specifically relating to a regular branched flue with an anti-wear and anti-ash accumulation system. Background Technology

[0002] Low-temperature economizers, as core equipment in flue gas waste heat recovery technology, are typically installed between the air preheater and dust collector in the flue gas duct of coal-fired power plants. They not only recover waste heat from flue gas but also improve electrostatic precipitator efficiency, efficiently remove SO3, reduce desulfurization tower water consumption, and decrease induced draft fan power consumption, resulting in significant economic and environmental benefits. However, the operating environment for low-temperature economizers is extremely harsh, characterized by high flue gas dust concentration, low flue gas temperature, compact installation space, and high ammonium bisulfate concentration, causing their actual lifespan to be far shorter than their design lifespan. The lifespan of low-temperature economizers is mainly limited by wear and leakage caused by ash accumulation. Furthermore, with the completion of ultra-low emission retrofits for coal-fired power units, the increasing demand for deep peak shaving in coal-fired power units, and the continuous deterioration of coal quality, the wear and ash accumulation problems of low-temperature economizers will become even more prominent.

[0003] The poor uniformity of the flue gas flow field caused by the variable cross-section structure and large bends in the flue is the main reason for wear and ash accumulation in low-temperature economizers. Currently installed low-temperature economizers are equipped with several sets of flue gas guide vanes in the inlet flue. However, due to varying technical levels and the lack of relevant evaluation systems, some only install guide vanes at the inlet diameter change of the economizer, and the design of these guide vanes deviates significantly from actual operating conditions, resulting in low applicability under different loads. In some cases, this even leads to increased fly ash enrichment, exacerbating wear on the low-temperature economizer. Therefore, exploring and developing flow-guided anti-wear structures is of great significance for the safe, stable, and long-term operation of low-temperature economizers. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention aims to provide a regular branched flue with an anti-wear and anti-ash accumulation system. By setting the anti-wear and anti-ash accumulation system at appropriate locations in the regular branched flue, the present invention can prevent wear of the heat exchange tube bundle of the low-temperature economizer and prevent ash accumulation, ensuring the utilization effect of the waste heat of the unit's flue gas and realizing the safe and stable operation of the thermal power plant.

[0005] The technical solution adopted in this invention is as follows:

[0006] A regularly branched flue with an anti-wear and anti-ash accumulation system includes a vertical turning flue, a horizontal turning flue, and a horizontal three-branched flue connected in sequence to the outlet of an air preheater. The horizontal three-branched flue includes a first branched flue, a second branched flue, and a third branched flue. The first and third branched flues are located on opposite sides of the second branched flue. The outlets of the first, second, and third branched flues are respectively connected to the front flue of a No. 1 low-temperature economizer, the front flue of a No. 2 low-temperature economizer, and the front flue of a No. 3 low-temperature economizer. The inlet of the front flue of the No. 2 low-temperature economizer is directly opposite the outlet of the second branched flue and the outlet of the front flue of the No. 2 low-temperature economizer.

[0007] The inlet end of the horizontal turning flue is equipped with a horizontal guide plate group at the flue diameter change point, and the corners of the horizontal turning flue are respectively equipped with a first flue turning point vertical guide plate group and a second flue turning point vertical guide plate group.

[0008] The inlet end of the horizontal three-forked flue is equipped with a vertical guide vane assembly at the bifurcation point of the flue;

[0009] In the horizontal three-branch flue, vertical guide arc-shaped baffle plates are provided at the inlet of the first branch flue and the inlet of the second branch flue, respectively; in the horizontal three-branch flue, vertical flow equalization baffle plates are provided at the outlet of the second branch flue.

[0010] In the horizontal three-branch flue, a vertical guide arc-shaped baffle plate group for the first branch flue is provided from the inlet to the outlet of the first branch flue, and a vertical guide arc-shaped baffle plate group for the second branch flue is provided from the inlet to the outlet of the third branch flue.

[0011] Preferably, the lower part of the vertical turning flue at the air preheater outlet is provided with a bottom ash conveying hopper for the vertical turning flue.

[0012] Preferably, the outlets of the first low-temperature economizer front flue, the second low-temperature economizer front flue, and the third low-temperature economizer front flue are all connected to the electrostatic precipitator front flue.

[0013] Preferably, the low-temperature economizer high-temperature module, the sonic soot blower, and the low-temperature economizer low-temperature module are sequentially arranged in the flue gas flow direction in front of the No. 1 low-temperature economizer.

[0014] The No. 2 low-temperature economizer front flue is equipped with the low-temperature economizer high-temperature module, the acoustic soot blower and the low-temperature economizer low-temperature module in sequence along the flue gas flow direction.

[0015] Along the flow direction of the flue gas, the No. 3 low-temperature economizer front flue is equipped with the high-temperature module of the low-temperature economizer, the sonic soot blower, and the low-temperature module of the low-temperature economizer.

[0016] Preferably, an ash conveying system is installed at the bottom of the flue gas ducts before the No. 1, No. 2, and No. 3 low-temperature economizers, below the area between the high-temperature module and the low-temperature module of the low-temperature economizer.

[0017] Preferably, the ash conveying system uses an ash hopper.

[0018] Preferably, a flue gas passage of a predetermined height is left between the lower end of the high-temperature module of the low-temperature economizer, the sonic soot blower, and the low-temperature module of the low-temperature economizer and the front flue of the No. 1 low-temperature economizer.

[0019] A flue gas passage of a preset height is left between the lower end of the high-temperature module of the low-temperature economizer, the acoustic soot blower, and the low-temperature module of the low-temperature economizer and the front flue of the No. 2 low-temperature economizer.

[0020] A flue gas passage of a preset height is left between the lower end of the high-temperature module of the low-temperature economizer, the acoustic soot blower, and the low-temperature module of the low-temperature economizer and the front flue of the No. 3 low-temperature economizer.

[0021] Preferably, the guide horizontal baffle assembly at the flue diameter change includes a number of straight plates arranged at intervals in the vertical direction;

[0022] The vertical guide vane group at the first flue bend and the vertical guide vane group at the second flue bend have the same structure and are symmetrically distributed on both sides of the inlet of the second bifurcation flue. They include a number of angled vertical vanes that are equidistantly arranged along the width of the flue, which are used to guide the flue gas flow in the horizontally turning flue to turn evenly.

[0023] The vertical guide vane assembly at the bifurcation point of the flue includes a number of angled vertical vanes arranged symmetrically at equal intervals along the width of the flue. These vanes are used to guide the flue gas flow to be divided into three branches and initially turn. The three branches flow to the first bifurcation flue, the second bifurcation flue, and the third bifurcation flue downstream, respectively.

[0024] The vertical guide arc-shaped baffle plate group at the entrance of the first branch flue and the vertical guide arc-shaped baffle plate group at the entrance of the second branch flue include a number of arc-shaped vertical plates arranged at intervals along the width of the flue, which are used to guide the flue gas flow in the first branch flue and the third branch flue to complete the turning evenly.

[0025] The vertical flow equalization guide plate assembly at the inlet of the bifurcation flue includes a number of parallel and equidistantly arranged channel steels, which are used to provide some resistance and make the flue gas flow uniformly distributed in the inlet section of the second bifurcation flue.

[0026] The first branch flue is provided with a plurality of vertically guiding arc-shaped guide plates for the first branch flue, and the second branch flue is provided with a plurality of vertically guiding arc-shaped guide plates for the second branch flue. The vertically guiding arc-shaped guide plates for the first branch flue and the second branch flue each include a plurality of arc-shaped plates, which are used to guide the flue gas flow to complete the turning evenly in the first branch flue and the third branch flue.

[0027] Preferably, the opening of the channel steel in the vertical flow equalization guide plate group at the inlet of the branch flue faces the flue in front of the No. 2 low-temperature economizer. The vertical flow equalization guide plate group at the inlet of the branch flue ensures that the flue gas throughput of the inlet section of the flue in front of the No. 2 low-temperature economizer is not less than 54%, and the spacing between the channel steels is not less than 200mm.

[0028] Preferably, the straight plate of the horizontal guide vane group at the flue diameter change, the angled vertical plate of the vertical guide vane group at the first flue bend and the second flue bend, the angled vertical plate of the vertical guide vane group at the flue bifurcation, the arc-shaped vertical plate of the vertical guide arc-shaped guide vane group at the inlet of the first bifurcation branch flue and the vertical guide arc-shaped guide vane group at the inlet of the second bifurcation branch flue, the channel steel of the vertical flow equalization guide vane group at the inlet of the bifurcation branch flue, and the arc-shaped plate of the vertical guide arc-shaped guide vane group at the inlet of the first bifurcation branch flue and the vertical guide arc-shaped guide vane group at the inlet of the second bifurcation branch flue are all provided with anti-wear structures on the side facing the flue gas flow.

[0029] The internal support rods in the vertical turning flue, horizontal turning flue, horizontal three-way bifurcation flue, the flue in front of the No. 1 low-temperature economizer, the flue in front of the No. 2 low-temperature economizer, and the flue in front of the No. 3 low-temperature economizer are all equipped with anti-wear structures on the side facing the flue gas flow.

[0030] The present invention has the following beneficial effects:

[0031] This invention, featuring a regular branching flue with anti-wear and anti-ash accumulation systems, allows for similar design schemes for similar flue structures during operation. Compared to traditional flow guiding systems, the upstream region of the flue involved in this invention extends to the air preheater outlet section, effectively avoiding the risk of flow field optimization deviations caused by insufficient consideration of incoming flow influences. By employing multiple sets of guide plates for collaborative optimization, vertical and horizontal flow guidance is performed step-by-step according to flow field characteristics. This mitigates abrupt changes in the flow field while improving the fault tolerance rate under different actual operating conditions. Simultaneously, it avoids prominent wear issues in individual parts, preventing premature damage and improving the overall wear resistance and service life of the flue. In summary, this invention's regular branching flue with anti-wear and anti-ash accumulation systems has advantages such as strong adaptability, low system resistance, and long service life. It can extend the replacement cycle of low-temperature economizer modules, enhancing the energy-saving and consumption-reducing capabilities and safe operation potential of coal-fired units.

[0032] Furthermore, by optimizing the structural layout of the low-temperature economizer and adding an acoustic soot blower, the present invention effectively reduces ash accumulation and potential wear problems.

[0033] Furthermore, the present invention also includes an ash conveying system, which effectively reduces ash accumulation and potential wear problems. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a regularly branched flue with an anti-wear and anti-ash accumulation system according to the present invention.

[0035] Figure 2(a) is a schematic diagram of the anti-wear measures for the internal support rods of the flue of the present invention; Figure 2(b) is a schematic diagram of the anti-wear measures for each guide plate of the present invention; Figure 2(c) is a schematic diagram of the anti-wear measures for each low-temperature economizer of the present invention.

[0036] Figure 3(a) is a front view of the flue gas flow field in the single-sided low-temperature economizer and its front flue of a 1,000 kW coal-fired unit in an embodiment of the present invention; Figure 3(b) is a perspective view of Figure 3(a); Figure 3(c) is a top view of Figure 3(a).

[0037] In the diagram, 1 is the vertical turning flue at the air preheater outlet, 1-1 is the ash conveying hopper at the bottom of the vertical turning flue, 2 is the horizontal turning flue, 3 is the horizontal branching flue, 4 is the flue before the No. 1 low-temperature economizer, 5 is the flue before the No. 2 low-temperature economizer, 6 is the flue before the No. 3 low-temperature economizer, 7-1 is the high-temperature module of the low-temperature economizer, 7-2 is the low-temperature module of the low-temperature economizer, 7-3 is the sonic soot blower, 7-4 is the ash conveying system, 8 is the flue before the electrostatic precipitator, 9 is the horizontal guide vane assembly at the flue diameter change, 10-1 is the vertical guide vane assembly at the bend of the first flue, and 10-2 is the... 11 is the vertical guide vane assembly at the bend of the second flue, 12-1 is the vertical guide vane assembly at the bifurcation point of the flue, 12-2 is the vertical guide arc-shaped vane assembly at the inlet of the first bifurcation branch flue, 13 is the vertical flow equalization vane assembly at the inlet of the bifurcation branch flue, 14-1 is the vertical guide arc-shaped vane assembly at the first bifurcation branch flue, 14-2 is the vertical guide arc-shaped vane assembly at the second bifurcation branch flue, 15 is the anti-wear angle steel, 16 is the support rod, 17 is the guide vane, 18 is the heat exchange tube, 19 is the flue gas passage, and 20 is the ash hopper. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, not all embodiments, and are not intended to limit the scope of the present invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessary confusion regarding the concepts disclosed in the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0039] The accompanying drawings show structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not drawn to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0040] refer to Figure 1The present invention features a regular branched flue with an anti-wear and anti-ash accumulation system, comprising a vertical turning flue 1, a horizontal turning flue 2, and a horizontal three-branched flue 3 connected in sequence at the air preheater outlet. The lower part of the vertical turning flue 1 is provided with a bottom ash hopper 1-1. The horizontal three-branched flue 3 includes a first branched flue, a second branched flue, and a third branched flue. The first and third branched flues are located on opposite sides of the second branched flue. The outlets of the first, second, and third branched flues are respectively connected to the front flue 4 of the No. 1 low-temperature economizer, the front flue 5 of the No. 2 low-temperature economizer, and the front flue 6 of the No. 3 low-temperature economizer. The inlet of flue 5 is directly opposite the outlet of the second branch flue and the outlet of the flue 5 before the No. 2 low-temperature economizer; the outlets of the flue 4 before the No. 1 low-temperature economizer, the flue 5 before the No. 2 low-temperature economizer, and the flue 6 before the No. 3 low-temperature economizer are all connected to the flue 8 before the electrostatic precipitator; in the flue 4 before the No. 1 low-temperature economizer, a high-temperature module 7-1, an acoustic soot blower 7-3, and a low-temperature module 7-2 of the low-temperature economizer are arranged sequentially along the flow direction of the flue gas; in the flue 5 before the No. 2 low-temperature economizer, a high-temperature module 7-1, an acoustic soot blower 7-3, and a low-temperature module 7-2 of the low-temperature economizer are arranged sequentially along the flow direction of the flue gas; in the flue 6 before the No. 3 low-temperature economizer, along the flow direction of the flue gas... The flow direction is sequentially provided with a high-temperature module 7-1 for the low-temperature economizer, an acoustic soot blower 7-3, and a low-temperature module 7-2 for the low-temperature economizer. At the bottom of the first low-temperature economizer front flue 4, the second low-temperature economizer front flue 5, and the third low-temperature economizer front flue 6, an ash conveying system 7-4 is installed below the area between the high-temperature module 7-1 and the low-temperature module 7-2. The ash conveying system 7-4 can be an ash hopper. Referring to Figure 2(c), a pre-set height flue gas channel 19 is left between the lower ends of the high-temperature module 7-1, the acoustic soot blower 7-3, and the low-temperature module 7-2 and the first low-temperature economizer front flue 4. The high-temperature module 7-1... -1. A flue gas passage of a preset height is left between the lower ends of the acoustic soot blower 7-3 and the low-temperature module 7-2 of the low-temperature economizer and the front flue 5 of the second low-temperature economizer; a flue gas passage of a preset height is left between the lower ends of the high-temperature module 7-1 of the low-temperature economizer, the acoustic soot blower 7-3 and the low-temperature module 7-2 of the low-temperature economizer and the front flue 6 of the third low-temperature economizer; the inlet end of the horizontal turning flue 2 is provided with a horizontal guide plate group 9 at the flue diameter change point, and the corners of the horizontal turning flue 2 are respectively provided with a vertical guide plate group 10-1 at the first flue bend and a vertical guide plate group 10-2 at the second flue bend; the inlet end of the horizontal three-forked flue 3 is provided with a vertical guide plate group 11 at the flue fork.In the horizontal three-branch flue 3, vertically guided arc-shaped guide vane groups 12-1 and 12-2 are respectively provided at the inlet ends of the first and third branch flues. In the horizontal three-branch flue 3, vertically guided arc-shaped guide vane groups 13 are provided at the inlet of the branch flue. In the horizontal three-branch flue 3, vertically guided arc-shaped guide vane groups 14-1 are provided from the inlet to the outlet of the first branch flue; one or more groups of these vertically guided arc-shaped guide vane groups 14-1 can be provided. In the horizontal three-branch flue 3, vertically guided arc-shaped guide vane groups 14-2 are provided from the inlet to the outlet of the third branch flue.

[0041] The overall structure formed by connecting the horizontal three-way bifurcation flue 3, the No. 1 low-temperature economizer front flue 4, the No. 2 low-temperature economizer front flue 5, and the No. 3 low-temperature economizer front flue 6 is an axisymmetric structure symmetrical about the No. 2 low-temperature economizer front flue 5. The No. 1 low-temperature economizer front flue 4 and the No. 3 low-temperature economizer front flue 6 are symmetrically arranged on both sides of the No. 2 low-temperature economizer front flue 5.

[0042] Specifically, in the above structure of the present invention, the guide horizontal flow deflector group 9 at the flue diameter change includes a combination of 8 to 12 horizontal straight plates, arranged in the horizontal turning flue 2 and close to the outlet of the vertical turning flue 1 of the air preheater outlet (i.e., the inlet end of the horizontal turning flue 2). The horizontal straight plates of the guide horizontal flow deflector group 9 at the flue diameter change are arranged at intervals in the vertical direction. In actual operation, the spacing between the horizontal straight plates can be adjusted according to the specific inflow distribution. The purpose is to initially rectify the unevenly distributed flue gas flow in the height direction at the outlet of the vertical turning flue 1 of the air preheater outlet into a uniform flue gas flow.

[0043] The first flue bend vertical guide vane group 10-1 and the second flue bend vertical guide vane group 10-2 each consist of a combination of 8 to 14 angled vertical vanes. In actual operation, the number and size can be adjusted according to the specific situation. They are respectively arranged at the two corners in the horizontal turning flue 2. The angled vertical vanes of the first flue bend vertical guide vane group 10-1 and the second flue bend vertical guide vane group 10-2 are arranged at equal intervals along the width of the flue, so as to keep the flue gas flow uniformly distributed after passing through multiple bends.

[0044] The vertical guide vane assembly 11 at the bifurcation point of the flue includes a combination of 14 to 20 angled vertical vanes. The vertical guide vane assembly 11 at the bifurcation point of the flue is arranged at the inlet of the horizontal three-branched flue 3. The angled vertical vanes of the vertical guide vane assembly 11 at the bifurcation point of the flue are arranged symmetrically at equal intervals along the width of the flue. They are used to guide the flue gas flow to be evenly divided into three branches and complete the initial turning, each flowing to the three downstream bifurcation branch flues.

[0045] The vertically oriented arc-shaped guide vane assembly 12-1 and the vertically oriented arc-shaped guide vane assembly 12-2 at the inlet of the first and third branch flues consist of a combination of 6 to 10 arc-shaped vertical vanes. The vertically oriented arc-shaped guide vane assembly 12-1 and the vertically oriented arc-shaped guide vane assembly 12-2 at the inlet of the first and second branch flues are respectively located upstream of the inlet of the No. 1 low-temperature economizer front flue 4 and the No. 3 low-temperature economizer front flue 6. The vertically oriented arc-shaped guide vane assembly 12-1 at the inlet of the first branch flue and the vertically oriented arc-shaped guide vane assembly 12-2 at the inlet of the second branch flue are arranged at unequal intervals along the width of the flue, used to guide the flue gas flow in the first and third branch flues to initially complete a uniform deflection; the vertically oriented flow equalizing guide vane assembly 13 at the inlet of the branch flue includes a combination of 10-16 channel steels, which are arranged in parallel and equidistantly at the inlet of the flue 5 in front of the No. 2 low-temperature economizer. The number of channel steels can be determined according to the actual situation. Adjustments are made based on actual conditions to provide partial flow resistance and achieve initial uniform distribution of flue gas flow in the inlet section. Specifically, the openings of the channel steel in the vertical flow equalization guide plate group 13 at the inlet of the branch flue face towards the flue 5 before the No. 2 low-temperature economizer. The vertical flow equalization guide plate group 13 at the inlet of the branch flue ensures that the flue gas throughput at the inlet section of the flue 5 before the No. 2 low-temperature economizer is not less than 54%, and the spacing between the channel steels is not less than 200mm; the vertical guide arc-shaped guide plate group 14-1 of the first branch flue and the second branch flue... The vertical guide arc-shaped baffle plate assembly 14-2 of the flue gas duct includes a combination of 7 to 11 arc-shaped plates. The vertical guide arc-shaped baffle plate assembly 14-1 of the first branch flue gas duct and the vertical guide arc-shaped baffle plate assembly 14-2 of the second branch flue gas duct are used to guide the flue gas flow to complete the turning evenly. One or more sets of the vertical guide arc-shaped baffle plate assembly 14-1 of the first branch flue gas duct and the vertical guide arc-shaped baffle plate assembly 14-2 of the second branch flue gas duct can be set. The specific number depends on the size of the corner of the first branch flue gas duct and the third branch flue gas duct.

[0046] In the above-described scheme of the present invention, referring to Figure 2(b), the straight plate of the horizontal guide plate group 9 at the flue diameter change, the angled vertical plate of the vertical guide plate group 10-1 at the first flue bend and the vertical guide plate group 10-2 at the second flue bend, the angled vertical plate of the vertical guide plate group 11 at the flue bifurcation, the arc-shaped vertical plate of the vertical guide arc-shaped guide plate group 12-1 at the inlet of the first bifurcation branch flue and the arc-shaped vertical plate of the vertical guide arc-shaped guide plate group 12-2 at the inlet of the second bifurcation branch flue, the channel steel of the vertical flow equalization guide plate group 13 at the inlet of the bifurcation branch flue, and the arc-shaped plate of the vertical guide arc-shaped guide plate group 14-1 at the first bifurcation branch flue and the vertical guide arc-shaped guide plate group 14-2 at the second bifurcation branch flue are all provided with anti-wear structures on the side facing the flue gas flow.

[0047] Referring to Figure 2(a), the inner support rods of the vertical turning flue 1, horizontal turning flue 2, horizontal three-forked flue 3, flue 4 in front of the No. 1 low-temperature economizer, flue 5 in front of the No. 2 low-temperature economizer, and flue 6 in front of the No. 3 low-temperature economizer are all equipped with anti-wear structures on the side facing the flue gas flow.

[0048] The aforementioned wear-resistant structure can be made of wear-resistant angle steel, which is welded to the corresponding guide plate or support rod, with the corner of the wear-resistant angle steel facing the direction of flue gas flow.

[0049] The working principle of the regularly branched flue with anti-wear and anti-ash accumulation system of the above-mentioned solution of the present invention is as follows:

[0050] Regarding flow field optimization: Along the main flue gas flow direction, the flue section from the air preheater outlet to the electrostatic precipitator inlet (including the ash hopper) is selected for flue gas flow field optimization. Based on the actual flow field conditions, guide vanes are installed at abrupt changes and bends in the flue. Flue gas flow field deterioration generally occurs at vertical and horizontal bends; therefore, small-sized, closely spaced straight plate groups, arc-shaped plate groups, or combinations of straight and arc-shaped plates are installed to guide the flue gas flow to complete the uniform turning process. Small-sized, closely spaced, folded guide vane groups are installed at flue bifurcation points to achieve uniform distribution and guidance of the flue gas flow. In particular, two sets of arc-shaped guide vane groups are installed in the first and third bifurcation branch flues, which are arc-shaped bend flues, to guide the flue gas flow to complete the uniform turning process in a stepped manner.

[0051] Regarding wear and ash accumulation prevention: The guide plates and flue support rods are equipped with wear-resistant structures on the side facing the flue gas flow. These structures protect the guide plates and flue support rods from being worn down by the ash-laden flue gas flow and losing their function. Since the No. 2 low-temperature economizer faces the ash-laden flue gas flow from the main flue, its modules are easily worn down. Therefore, a vertical flow-equalizing guide plate assembly is installed at the inlet of flue 5 before the No. 2 low-temperature economizer. This not only prevents the ash-laden flue gas flow from directly impacting the heat exchange tube bundle but also serves to equalize the flow. Regarding ash accumulation prevention, the low-temperature... Sonic soot blowers 7-3 are installed after the high-temperature module 7-1 of the economizer and before the low-temperature module 7-2 of the low-temperature economizer. These blowers periodically clean the system. Simultaneously, flue gas channels 19 of a certain height are reserved below the high-temperature module 7-1, the low-temperature module 7-2, and the sonic soot blowers 7-3, as well as at the bottom of the flue before the low-temperature economizer. These channels allow some high-speed airflow to carry away the accumulated ash at the bottom. An ash hopper 20 is also installed at the bottom of the flue to minimize ash accumulation on the heat exchange tube surface and at the bottom of the flue. Adopting a design concept based on global optimization across the entire flow domain, the overall system resistance and comprehensive renovation costs are considered holistically. Segmented flow guidance and anti-wear and anti-ash accumulation designs are implemented in key areas, effectively extending the lifespan of the low-temperature economizer.

[0052] The above-mentioned solution of the present invention adopts the design concept based on the whole flow domain global optimization, takes into account the overall system resistance and comprehensive transformation cost, and carries out the design of segmented flow diversion and anti-wear and anti-ash accumulation in key parts, which effectively extends the service life of the low temperature economizer equipment.

[0053] Figures 3(a)-3(c) The following are the flow field optimization results of a specific embodiment in this invention. The maximum flow velocity at the inlet section of the low-temperature economizer decreased from 16.88 m / s to 8.65 m / s, and the relative root mean square difference of the inlet section velocity decreased successively from 30.90%, 49.63%, and 26.20% to 14.92%, 6.72%, and 14.76%. Both the extreme velocity value and the relative velocity deviation value were reduced by more than half, which not only prevented local wear and leakage in the low-temperature economizer module, but also ensured the heat exchange effect of the equipment.

Claims

1. A regularly branched flue with an anti-wear and anti-ash accumulation system, characterized in that, It includes a vertical turning flue (1), a horizontal turning flue (2), and a horizontal three-branched flue (3) connected in sequence to the air preheater outlet. The horizontal three-branched flue (3) includes a first branch flue, a second branch flue, and a third branch flue. The first branch flue and the third branch flue are located on both sides of the second branch flue. The outlets of the first branch flue, the second branch flue, and the third branch flue are respectively connected to the first low-temperature economizer front flue (4), the second low-temperature economizer front flue (5), and the third low-temperature economizer front flue (6). The inlet of the second low-temperature economizer front flue (5) is directly opposite the outlet of the second branch flue and the outlet of the second low-temperature economizer front flue (5). The inlet end of the horizontal turning flue (2) is provided with a horizontal guide plate group (9) at the flue diameter change point, and the corners of the horizontal turning flue (2) are respectively provided with a first flue turning point vertical guide plate group (10-1) and a second flue turning point vertical guide plate group (10-2). The inlet end of the horizontal three-forked flue (3) is provided with a vertical guide vane assembly (11) at the bifurcation point of the flue; In the horizontal three-branch flue (3), vertical guide arc-shaped guide plate group (12-1) at the inlet of the first branch flue and vertical guide arc-shaped guide plate group (12-2) at the inlet of the second branch flue are respectively provided at the inlet of the first branch flue; in the horizontal three-branch flue (3), vertical flow equalization guide plate group (13) at the inlet of the branch flue is provided at the outlet of the second branch flue; In the horizontal three-branch flue (3), a first branch flue vertical guide arc-shaped guide plate group (14-1) is provided at the inlet to outlet of the first branch flue, and a second branch flue vertical guide arc-shaped guide plate group (14-2) is provided at the inlet to outlet of the second branch flue in the horizontal three-branch flue (3).

2. A regularly branched flue with an anti-wear and anti-ash accumulation system according to claim 1, characterized in that, The lower part of the vertical turning flue (1) at the outlet of the air preheater is provided with a bottom ash hopper (1-1) of the vertical turning flue.

3. A regularly branched flue with an anti-wear and anti-ash accumulation system according to claim 1, characterized in that, The outlets of the No. 1 low-temperature economizer front flue (4), the No. 2 low-temperature economizer front flue (5), and the No. 3 low-temperature economizer front flue (6) are all connected to the electrostatic precipitator front flue (8).

4. A regularly branched flue with an anti-wear and anti-ash accumulation system according to claim 1, characterized in that, The first low-temperature economizer front flue (4) is provided with a high-temperature module (7-1), an acoustic soot blower (7-3) and a low-temperature module (7-2) of the low-temperature economizer in sequence along the flow direction of the flue gas. The front flue (5) of the No. 2 low-temperature economizer is provided with the high-temperature module (7-1), the sonic soot blower (7-3) and the low-temperature module (7-2) of the low-temperature economizer in sequence along the flow direction of the flue gas. The front flue (6) of the No. 3 low-temperature economizer is provided with the high-temperature module (7-1), the sonic soot blower (7-3) and the low-temperature module (7-2) of the low-temperature economizer in sequence along the flow direction of the flue gas.

5. A regularly branched flue with an anti-wear and anti-ash accumulation system according to claim 4, characterized in that, At the bottom of the No. 1 low-temperature economizer front flue (4), the No. 2 low-temperature economizer front flue (5), and the No. 3 low-temperature economizer front flue (6), an ash conveying system (7-4) is set below the area between the high-temperature module (7-1) and the low-temperature module (7-2) of the low-temperature economizer.

6. A regularly branched flue with an anti-wear and anti-ash accumulation system according to claim 5, characterized in that, The ash conveying system (7-4) uses an ash hopper.

7. A regularly branched flue with an anti-wear and anti-ash accumulation system according to claim 5 or 6, characterized in that, A flue gas passage of a preset height is left between the lower ends of the high temperature module (7-1) of the low temperature economizer, the sonic soot blower (7-3) and the low temperature module (7-2) of the low temperature economizer and the front flue (4) of the No. 1 low temperature economizer. A flue gas passage of a preset height is left between the lower ends of the high temperature module (7-1) of the low temperature economizer, the sonic soot blower (7-3) and the low temperature module (7-2) of the low temperature economizer and the front flue (5) of the second low temperature economizer. A flue gas passage of a preset height is left between the lower end of the high temperature module (7-1) of the low-temperature economizer, the sonic soot blower (7-3) and the low temperature module (7-2) of the low-temperature economizer and the front flue (6) of the No. 3 low-temperature economizer.

8. A regularly branched flue with an anti-wear and anti-ash accumulation system according to claim 1, characterized in that, The guide horizontal baffle assembly (9) at the flue diameter change includes a number of straight plates arranged at intervals in the vertical direction; The vertical guide vane group (10-1) at the first flue bend and the vertical guide vane group (10-2) at the second flue bend have the same structure and are symmetrically distributed on both sides of the inlet of the second bifurcation flue. They include a number of angled vertical plates that are equidistantly arranged along the width of the flue, which are used to guide the flue gas flow in the horizontal turning flue (2) to turn evenly. The vertical guide vane assembly (11) at the bifurcation of the flue includes a number of angled vertical vanes arranged symmetrically at equal intervals along the width of the flue, which are used to guide the flue gas flow to be divided into three branches and initially turn. The three branches flow to the first bifurcation flue, the second bifurcation flue and the third bifurcation flue downstream respectively. The vertical guide arc-shaped baffle plate group (12-1) at the entrance of the first branch flue and the vertical guide arc-shaped baffle plate group (12-2) at the entrance of the second branch flue include a number of arc-shaped vertical plates arranged at intervals along the width of the flue, which are used to guide the flue gas flow in the first branch flue and the third branch flue to complete the turning evenly. The vertical flow equalization guide plate group (13) at the inlet of the bifurcation flue includes a number of parallel and equidistant channel steels, which are used to provide some resistance and make the flue gas flow uniformly distributed in the inlet section of the second bifurcation flue. The first branch flue is provided with a plurality of vertical guide arc-shaped guide plates (14-1) for the first branch flue, and the second branch flue is provided with a plurality of vertical guide arc-shaped guide plates (14-2) for the second branch flue. Both the vertical guide arc-shaped guide plates (14-1) for the first branch flue and the vertical guide arc-shaped guide plates (14-2) for the second branch flue include a plurality of arc-shaped plates, which are used to guide the flue gas flow to complete the turning evenly in the first branch flue and the third branch flue, respectively.

9. A regularly branched flue with an anti-wear and anti-ash accumulation system according to claim 8, characterized in that, The opening of the channel steel in the vertical flow equalization guide plate group (13) at the inlet of the branch flue is directed toward the flue (5) in front of the No. 2 low-temperature economizer. The vertical flow equalization guide plate group (13) at the inlet of the branch flue ensures that the flue gas throughput of the inlet section of the flue (5) in front of the No. 2 low-temperature economizer is not less than 54%, and the spacing between the channel steels is not less than 200mm.

10. A regularly branched flue with an anti-wear and anti-ash accumulation system according to claim 8, characterized in that, The straight plate of the horizontal guide plate group (9) at the flue diameter change, the angled vertical plate of the vertical guide plate group (10-1) at the first flue bend and the vertical guide plate group (10-2) at the second flue bend, the angled vertical plate of the vertical guide plate group (11) at the flue bifurcation, the arc-shaped vertical plate of the vertical guide plate group (12-1) at the flue inlet of the first bifurcation branch and the arc-shaped vertical plate of the vertical guide plate group (12-2) at the flue inlet of the second bifurcation branch, the channel steel of the vertical flow equalization guide plate group (13) at the flue inlet of the bifurcation branch, and the arc-shaped plate of the vertical guide plate group (14-1) at the first bifurcation branch and the vertical guide plate group (14-2) at the second bifurcation branch are all provided with anti-wear structures on the side facing the flue gas flow. The inner support rods of the air preheater outlet vertical turning flue (1), horizontal turning flue (2), horizontal three-forked flue (3), No. 1 low-temperature economizer front flue (4), No. 2 low-temperature economizer front flue (5) and No. 3 low-temperature economizer front flue (6) are all equipped with anti-wear structures on the side facing the flue gas flow.

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