CN113137621B - Flue distributor utilizing heat pipe for temperature equalization - Google Patents
Flue distributor utilizing heat pipe for temperature equalization Download PDFInfo
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- CN113137621B CN113137621B CN202011093969.XA CN202011093969A CN113137621B CN 113137621 B CN113137621 B CN 113137621B CN 202011093969 A CN202011093969 A CN 202011093969A CN 113137621 B CN113137621 B CN 113137621B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J15/00—Arrangements of devices for treating smoke or fumes
- F23J15/02—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material
- F23J15/022—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material for removing solid particulate material from the gasflow
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J15/00—Arrangements of devices for treating smoke or fumes
- F23J15/06—Arrangements of devices for treating smoke or fumes of coolers
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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
- Y02E20/30—Technologies for a more efficient combustion or heat usage
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Abstract
The invention provides a flue distributor utilizing heat pipes to equalize temperature, which is arranged between an air preheater and an economizer and is L-shaped, wherein the distributor comprises a vertical part and a horizontal part, the vertical part is positioned at the upstream, and the horizontal part is positioned at the downstream. According to the invention, the heat pipe is arranged in the flue distributor, so that the temperature of the flue gas at the outlet of the distributor is uniform, the requirement of further heat exchange is met, and the service life of the product is prolonged.
Description
Technical Field
The invention relates to the field of heat exchangers, in particular to a heat exchange system for flue distribution.
Background
The L-shaped flue gas distributor is common equipment of an outlet flue of the air preheater and is used for equally distributing flue gas at an outlet of a flue gas side of the air preheater, reducing the flow of the flue gas at the inlet of a single dust remover and improving the dust removal efficiency. The low-temperature coal economizer is arranged at the outlet of the distributor and the inlet of the dust remover, so that the exhaust gas temperature can be further reduced, the boiler efficiency is improved, and the pollutant emission is reduced. The performance of the distributor has important significance for stable and efficient operation, energy conservation, emission reduction and the like of the thermal power generating unit. The flue gas flow, ash amount and temperature uniformity of the branch flue at the downstream of the distributor are important indexes for evaluating the performance of the distributor. The traditional flue gas distributor realizes the uniformity of the flue gas and ash amount of each branch flue in a branch flue outlet throttling mode, but a reliable means for solving the problem of non-uniform temperature of the flue gas at the outlet of the distributor is not provided yet. The maximum temperature difference of each branch flue at the downstream of the traditional flue gas distributor is higher than 50 ℃, and the running stability of downstream equipment is seriously damaged.
A large thermal power generating unit generally adopts a rotary air preheater to recover waste heat of a tail flue, and a heat exchange mode of periodic flow heat storage enables flue gas at an outlet of the air preheater to have larger temperature difference in the tangential direction, and the maximum temperature difference in the tangential direction of the rotary air preheater can reach 100 ℃ under normal operation conditions. If the air preheater has serious problems of ash blockage, corrosion, air leakage and the like under the long-term operation condition, the tangential temperature difference of the flue gas at the outlet of the air preheater is far higher than 100 ℃. The tangential huge temperature difference of the flue gas at the outlet of the air preheater enables the temperature of the flue gas at the inlet of the distributor to be uneven, the mixing length in the distributor is limited, the flue gas is difficult to be completely mixed, and finally the temperature of the flue gas at the outlet of the distributor is uneven.
The too big influence that causes the operation of flue gas temperature deviation behind air preheater export flue gas distributor:
usually, a low-temperature economizer is arranged between the air preheater and the dust remover and used for recovering the waste heat of the flue gas, and at present, condensed water is commonly used for recovering the heat. Generally, the low-temperature coal economizer of each flue gas flow passage in front of the dust remover has the same heat exchange area and heat exchange capacity. If the flue gas temperature deviation is large, the flue gas temperature of some flow passages is lower than the original design value, and the flue gas temperature of some flow passages is higher than the original design value. Under the condition that the flue gas temperature is lower than the design value of the inlet flue gas temperature of the low-temperature economizer, the heat exchange area of the low-temperature economizer of the flow channel is excessive, so that waste is caused, and if the flue gas temperature is equivalent to the design value of the outlet flue gas temperature of the low-temperature economizer, the low-temperature economizer on the flow channel cannot be put into operation, namely, the flue gas resistance is increased, and the economic benefit on heat is not obtained. Under the condition that the flue gas temperature is higher than the design value of the inlet flue gas temperature of the low-temperature economizer, the heat exchange area of the low-temperature economizer of the flow channel is insufficient, although some allowance exists when the low-temperature economizer is selected, if the flue gas temperature exceeds the design value too much, the outlet flue gas temperature of the low-temperature economizer cannot be reduced to the outlet flue gas temperature of the designed low-temperature economizer, and heat waste is caused.
The heat exchange areas and the like of the low-temperature economizers on each channel are the same, the inlet flue gas temperatures are different, in order to reach the same outlet flue gas temperature, the condensate flow of each low-temperature economizer is different, and a regulating valve is further arranged on a water pipeline of each low-temperature economizer, so that the operation and regulation are difficult.
The temperature of the inlet of the low-temperature economizer has deviation, while the temperature of the outlet of the low-temperature economizer is the same, so that the actual flue gas volume deviation of each channel is aggravated, the flue gas volume deviation in each channel of the dust remover is caused, and the dust removal effect is influenced to a certain extent.
The heat pipe technology is a heat transfer element called a heat pipe invented by George Grover (George Grover) of national laboratory of Los Alamos (Los Alamos) in 1963, fully utilizes the heat conduction principle and the rapid heat transfer property of a phase change medium, quickly transfers the heat of a heating object to the outside of a heat source through the heat pipe, and the heat conduction capability of the heat transfer element exceeds the heat conduction capability of any known metal.
The heat pipe technology is widely applied to the industries of aerospace, military industry and the like, and since the heat pipe technology is introduced into the radiator manufacturing industry, the design idea of the traditional radiator is changed for people, the single heat radiation mode that a high-air-volume motor is used for obtaining a better heat radiation effect is avoided, the heat pipe technology is adopted for enabling the radiator to obtain a satisfactory heat exchange effect, and a new place in the heat radiation industry is opened up. At present, the heat pipe is widely applied to various heat exchange devices, including the temperature equalization field.
Therefore, in view of the above-mentioned drawbacks, the present patent provides a boiler system with a flue distributor of a heat pipe temperature equalizing device, and also provides a new flue distributor. The distributor aims to improve the structure of the L-shaped flue distributor so as to achieve the uniform temperature of the flue gas at the outlet of the distributor, realize the requirement of further heat exchange and prolong the service life of products.
Disclosure of Invention
One of the main objects of the present invention is to provide a boiler system with a flue distributor, which improves the structure of the L-shaped flue distributor to achieve uniform flue gas temperature at the outlet of the distributor, so as to meet the requirement of further heat exchange and prolong the service life of the product.
In order to achieve the purpose, the invention adopts the following technical scheme:
the utility model provides an utilize flue distributor of heat pipe samming, flue distributor sets up between air heater and economizer, flue distributor is L shape, and the distributor includes vertical portion and horizontal part, and vertical portion is located the upper reaches, and the horizontal part is located the low reaches, and characterized in that, vertical portion sets up the heat pipe, the heat pipe extends to another lateral wall of vertical portion from a lateral wall bottom of vertical portion, and wherein the evaporation end setting of heat pipe is in a lateral wall bottom of vertical portion, and the condensation end setting of heat pipe is in another lateral wall of vertical portion, and wherein the flue gas temperature of heat pipe evaporation end is higher than the flue gas temperature of heat pipe condensation end.
Preferably, the heat pipe extends obliquely and extends obliquely upwards from the evaporation end to the condensation end of the heat pipe.
Preferably, the condensation end is disposed at a position above the middle of the other side wall.
Preferably, the condensation end is disposed at a position above three-quarters of the height of the other side wall.
As a preference, the first and second liquid crystal compositions are,
wherein n represents the number of heat pipes, t represents the temperature, h represents the surface heat transfer coefficient, x represents the distance from the bottom of the heat pipe, L represents the length of the heat pipe,
which represents the coefficient of thermal conductivity of the material,
which represents the average incoming flow velocity of the fluid,
which is indicative of the density of the fluid,
denotes the fluid viscosity, cp denotes the fluid specific heat, and d denotes the heat pipe outer diameter. The subscript x represents the local value, f represents the fluid, w represents the wall, 0 represents the hot end of the heat pipe, l represents the cold end of the heat pipe,
representing the equivalent thermal conductivity of the heat pipe.
Preferably, the guide plates are arranged in the vertical part, the guide plates are arranged on the upper part of the heat pipe, the guide plates are divided into two rows, and a space is arranged between every two adjacent guide plates in each row; the first row extends inwardly from one side wall of the upright portion, the second row extends inwardly from the other side of the upright portion, the spacing between the first row of baffles is opposite the second row of baffles, and the spacing between the second row of baffles is opposite the first row of baffles.
Preferably, the vertical portion and the horizontal portion are both rectangular in cross-section.
Preferably, the baffle is circular.
Preferably, a chord inclination angle theta is formed by a connecting line of the top ends of the two side walls and a connecting line of two end points of the guide plate, a chord tangent angle phi is formed by a tangent line of the other end of the guide plate far away from the side walls and a connecting line of the two end points of the guide plate, the height of the vertical part is H, and the distance between the intersection point of the two guide plates and the upper end surface of the horizontal part is a vacant section H; the distance between the two side walls is L;
h <1/3H, the calculation formula is as follows:
the chord dip angle theta = 30-60 degrees.
Preferably, the chord inclination angle theta = 45-60 degrees.
Compared with the prior art, the invention has the beneficial effects that:
1) the invention provides a novel L-shaped flue distributor, which is characterized in that the flue distributor is internally provided with a heat pipe, so that the temperature of flue gas at the outlet of the distributor is uniform, the requirement of further heat exchange is met, and the service life of a product is prolonged.
2) The invention calculates and optimizes the heat exchange condition of the heat pipe of the flue distributor so as to achieve the optimal outlet flue gas temperature equalization effect.
Drawings
FIG. 1 is a schematic structural view of a boiler system;
FIG. 2 is a schematic diagram of a prior art L-shaped flue distributor;
FIG. 3 is a schematic structural view of an L-shaped flue distributor of the present application incorporating heat pipes;
FIG. 4 is a schematic structural view of the present application of an L-shaped flue distributor with baffles;
FIG. 5 is a front view of the L-shaped flue distributor of the present application;
FIG. 6 is a top view of the L-shaped flue distributor of the present application;
FIG. 7 is a left side view of the L-shaped flue distributor of the present application;
FIG. 8 is an elevation view of an L-shaped flue distributor of the present application;
FIG. 9 is a parametric schematic of an L-shaped flue distributor of the present application;
FIG. 10 is a schematic diagram of the structure of an L-shaped flue distributor of the present application with heat pipes and baffles;
FIGS. 11 and 12 are schematic size views of an L-shaped flue distributor of the present application with heat pipes and baffles;
fig. 13 and 14 are schematic size views of an L-shaped flue distributor of the present application with heat pipes and flue.
The reference numbers are as follows:
1-ash bucket connecting flange; 2-upper guard board; 3-lower guard board; 4-bottom guard board; 5-ash bucket interface; 6-flue outlet guard board; 7-flue outlet flange; 8-a flow guide plate; 9-a framework; 10-flue outlet support truss; 11, 12-horizontal force diagonal bracing; 13-16-columns; 17, 18-support; 19 a square manhole; 20-a steel plate; 21-25 angle steel; 26-fine ash slatted doors; 27-H section bar; 28-steel plate; 29-32-H section bar; 33-a non-metallic expansion joint; 34 boiler, 35 air preheater, 36 economizer, 37 dust remover, L-shaped flue gas distributor 38, 39 heat pipes.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings.
Fig. 1 discloses a schematic structural view of a boiler system. As shown in fig. 1, the boiler system includes a boiler 34, a flue gas outlet is arranged at the top of the boiler 34, the flue gas outlet is connected with a flue, an air preheater 35, an economizer 36 and a dust remover 37 are sequentially arranged in the flue, and an L-shaped flue gas distributor 38 is arranged between the air preheater 35 and the economizer 36.
In operation, pulverized coal is combusted in a hearth to generate smoke, the smoke enters an air preheater 35 after flowing through a water-cooled wall and a superheater, primary air and secondary air are heated in the air preheater 35 and then enter an L-shaped smoke distributor 38, the smoke coming out of the L-shaped smoke distributor 38 is divided into multiple paths (preferably three paths) and respectively enters a plurality of (preferably three) low-temperature economizers 36, the smoke enters a dust remover 37 for dust removal after the boiler is heated in the economizer 36 to return water, and the smoke after dust removal is discharged through a chimney.
As shown in fig. 2 and 3, L-shaped flue distributor 38 comprises a vertical part 381 and a horizontal part 382, vertical part 381 is located upstream, horizontal part 382 is located downstream, the upper part of vertical part is a flue gas inlet, the end of horizontal part is a flue gas outlet, the flue gas outlet is multiple (preferably 3), and each flue gas outlet is connected with one economizer 36. As shown in fig. 2, the temperature of the flue gas at different positions in the flue is different, so that the problem of uneven distribution of the temperature of the flue gas exists in the three flue gas channels connected with the tail part of the L-shaped flue gas distributor, and as shown in fig. 2, the temperature difference between the flue gas outlet 1 and the flue gas outlet 3 can reach 60 ℃.
In the following description, if not specifically stated, the height direction of the vertical portion is the up-down direction, the direction of the smoke outlet is the left direction, the direction opposite to the smoke outlet direction is the right direction, and the direction perpendicular to the smoke outlet direction is the front-back direction.
The invention relates to an L-shaped smoke distributor. As a modification, as shown in fig. 3, the vertical portion 381 is provided with a heat pipe 39, the heat pipe 39 extends from the bottom of one side wall of the vertical portion to the other side wall of the vertical portion, wherein the evaporation end 391 of the heat pipe is arranged at the bottom of one side wall of the vertical portion, and the condensation end 392 of the heat pipe is arranged at the other side wall of the vertical portion, wherein the temperature of the flue gas at the evaporation end of the heat pipe is higher than that at the condensation end of the heat pipe.
According to the invention, the heat pipe is arranged, so that the high-temperature heat of the flue gas entering the L-shaped distributor is transferred to the low-temperature part through the heat pipe, and the heat of the heat pipe in the whole flue gas distributor is kept uniform in temperature, thereby realizing uniform temperature of the flue gas, avoiding the problem caused by uneven outlet flue gas, and keeping the flue gas temperature of the flue gas outlets at different positions balanced.
Preferably, the heat pipe extends obliquely and extends obliquely upwards from the evaporation end to the condensation end of the heat pipe. Through the slope setting for the backward flow condensate liquid that the heat pipe can be timely reaches quick heat transfer.
Preferably, the condensation end is disposed at a position above the middle of the other side wall.
Preferably, the condensation end is disposed at a position above three-quarters of the height of the other side wall.
Through the setting position of condensation end, can make flue gas temperature distribution more even.
The invention further researches the structure and the heat exchange condition of the structure.
Preferably, the partial heat exchange in the flue distributor meets the following requirements:
wherein n represents the number of heat pipes, t represents the temperature, h represents the surface heat transfer coefficient, x represents the distance from the bottom of the heat pipe, L represents the length of the heat pipe,
which represents the coefficient of thermal conductivity of the material,
which represents the average incoming flow velocity of the fluid,
which is indicative of the density of the fluid,
denotes the fluid viscosity, cp denotes the fluid specific heat, and d denotes the heat pipe outer diameter. The subscript x represents the local value, f represents the fluid, w represents the wall, 0 represents the hot end of the heat pipe, and 1 represents the cold end of the heat pipe.
Representing the equivalent thermal conductivity of the heat pipe.
The first integral is the total heat exchange amount between the heat pipe and the flue gas along the axial direction of the heat pipe. Because the heat pipe plays the middle heat exchange effect, can't transfer the flue gas heat energy, so the heat transfer total amount on the heat pipe surface is 0, accords with the energy conservation.
Through the combination of the above formulas, relevant parameters such as the number of heat pipes, the nussel number and the like can be calculated.
The heat exchange performance of the structure can be estimated and whether the temperature uniformity requirement is met or not can be estimated according to the above types.
The above-mentioned structural heat exchange formula is a main improvement point of the present invention, and is an optimal heat exchange formula obtained through a large number of numerical simulations and experimental studies, and is not common knowledge in the art.
The invention relates to an L-shaped smoke distributor. As an improvement, as shown in fig. 4, a plurality of baffles 8 are arranged inside the vertical portion 381, preferably, the baffles 8 are arranged on the upper portion of the heat pipe, the number of the baffles 8 is at least two, the baffles are divided into two rows, and a space is arranged between adjacent baffles in each row; the first row extends inwardly from one side wall of the upright portion, the second row extends inwardly from the other side of the upright portion, the spacing between the first row of baffles is opposite the second row of baffles, and the spacing between the second row of baffles is opposite the first row of baffles.
The invention ensures that the heat exchange is more uniform through the double cooperation of the guide plate and the heat pipe.
As shown in fig. 4 and 8, the first row of baffles is disposed on the left or right side of the front side wall, and the second row of baffles is disposed on the right or left side of the rear side wall corresponding to the front side wall row, so as to achieve the staggered arrangement.
According to the invention, two rows of arc-shaped guide plates are arranged, so that a part of the flue gas entering the L-shaped distributor flows along the arc-shaped guide plates and is guided to the opposite direction, the flue gas is fully mixed with the flue gas on the other side at the interval position, and the arrangement of the heat pipe is preferably combined, so that the temperature uniformity of the flue gas is realized, and the problem caused by uneven outlet flue gas is avoided.
Preferably, the baffle is of arcuate configuration.
Preferably, the connection width of each baffle at the side wall in planar projection is 50% of the side wall width W when viewed from the upper part of the vertical part downward (in a top view in the height direction).
Preferably, the length of each baffle extending from the side wall to the inside of the vertical portion in planar projection is 50% of the distance L between the two side walls, as viewed from the upper part of the vertical portion downward (as viewed in the height direction from above).
Through the size design, on one hand, the guide plates can be distributed in the space as much as possible, the temperature is sufficiently and uniformly realized, the short circuit phenomenon in the flue gas flow can be avoided, the flue gas is prevented from flowing out from one direction, and the flue gas can be mixed to achieve an optimal structure.
Preferably, the position where the baffle is connected to the side wall is disposed at the uppermost end of the side. Through setting up in the top for vertical portion inner space is enough big in order to satisfy intensive mixing.
Preferably, the vertical portion 381 and the horizontal portion 382 are rectangular in cross-section.
Preferably, the baffle is circular.
A chord inclination angle theta formed by a connecting line of the top ends of the two side walls and a connecting line of two end points of the guide plate 8, a chord tangent angle phi formed by a tangent line of the other end of the guide plate 8 far away from the side walls and a connecting line of two end points of the guide plate 8, the height of the vertical part 381 is H (the distance from the uppermost end of the vertical part to the upper end surface of the horizontal part), and the distance from the intersection point of the two guide plates 8 to the upper end surface of the horizontal part is a vacant section H; the distance between the two side walls is L.
Through a large number of numerical simulation and experimental research, the arrangement mode of the guide plate 8 comprehensively considers the flow distribution, mixing, resistance, vibration, ash discharge and the like. The chord inclination angle theta of the guide plate 8 is not too small, otherwise the static pressure and the dynamic pressure on the surface of the guide plate are higher, the flow resistance is increased, and not too large, otherwise the occupied space is too large, and the structure size is complex; the inclination angle is less, and the ash particle should not fall off from the board surface, and guide plate upper surface area ash is serious for the guide plate is difficult to support. The chord tangent angle phi of the guide plate is not too high, and the ash discharge is also not facilitated. The empty section h should not be too small, otherwise the local flow velocity near the ash bucket is too high, which is not beneficial to ash discharge of the ash bucket.
Preferably, H is more than or equal to 1/3H and phi is less than or equal to 20 degrees under the allowable condition of spatial arrangement, and the radius of the circular arc guide plate can be calculated according to the following formula:
preferably, the chord inclination angle θ =45 to 60 ° of the baffle 8.
If the condition that H is more than or equal to 1/3H is difficult to satisfy, namely H is less than 1/3H, the radius of the guide plate is calculated by H, and the calculation formula is as follows:
preferably, the chord inclination angle θ =30 to 60 °, and more preferably θ =45 to 60 ° of the baffle 8.
When θ is equal to or lower than 30 °, a straight plate is preferably used.
To prevent the baffle from vibrating, the thickness of the baffle is preferably not less than 5 mm.
Through the design of the radius R of the guide plate, the temperature of the flue gas of the flue distributor can reach the optimal temperature equalizing effect under the condition of meeting the heat exchange and smoke exhaust requirements.
The guide plate is supported by support rods, and the support rods preferably have the outer diameter not less than 38mm and the inner diameter not less than 4 mm. The transverse support rods are arranged on the leeward side of the guide plate, the arrangement number and the arrangement distance of the transverse support rods are the same as those of H-shaped reinforcing ribs outside the L-shaped flue gas distributor, and the transverse support rods are welded in a flush joint mode. The longitudinal support rod penetrates through the guide plate and is welded on the guide plate in the circumferential direction. The longitudinal support rod is welded with the transverse support rod. The longitudinal support bars are at the same distance in the length direction as the transverse support bars, and the distance in the width direction is not higher than W/8.
In operation, flue gas generated in the boiler 34 enters the air preheater 35, heats the primary air and the secondary air, and then enters the L-shaped flue gas distributor 38. An ash bucket connecting flange 1 of an L-shaped flue gas distributor 38 is connected with a nonmetal compensator at an outlet of an air preheater, an upper protection plate 2 is used for reinforcing a wall plate of an upper flue, a lower protection plate 3 is used for reinforcing a wall plate of a lower flue, a bottom protection plate 4 is used for reinforcing a wall plate at the bottom of the flue, an ash bucket interface 5 is used for discharging bottom deposited ash and discharging rinsing water of the air preheater, a flue outlet protection plate 6 is used for reinforcing a horizontal flue wall plate at an outlet of the flue, a flue outlet flange 7 is used for connecting with other subsequent components, a guide plate 8 is used for guiding flue gas, a flue outlet supporting truss 10 is used for reinforcing the outlet flue, horizontal force diagonal braces 11 and 12 are used for stabilizing the whole flue component, upright columns 13-16 are used for supporting a vertical flue, supports 17 and 18 are used for supporting the horizontal flue, a square manhole 19 is used for an access person to the inside the flue, a steel plate 20 is used for reinforcing the support, and angle steels 21-25 are used for preventing the supporting truss inside the flue from being worn, the fine ash inserting plate door 26 is used for controlling ash discharge at the bottom of the ash bucket, the H-shaped material 27 is used for manufacturing a limiting hanger, the steel plate 28 is used for manufacturing the limiting hanger, and the H-shaped materials 29-32 are used for manufacturing the limiting hanger. The L-shaped flue gas distributor 38 is connected with the economizer 36 through the non-metal expansion joint 33, and flue gas flows through the economizer 36, is heated and returns water, and then enters the dust remover 37.
Preferably, the heat exchange condition of the structure with the guide plate and the heat pipe is researched, and the heat exchange condition of the heat pipe with the structure is researched.
Wherein n represents the number of heat pipes, t represents the temperature, h represents the surface heat transfer coefficient, x represents the distance from the bottom of the heat pipe, L represents the length of the heat pipe,
which represents the coefficient of thermal conductivity of the material,
the speed of the incoming flow is indicated,
which is indicative of the density of the fluid,
denotes the fluid viscosity, cp denotes the fluid specific heat, and d denotes the heat pipe outer diameter. The subscript x represents the local value, f represents the fluid, w represents the wall, 0 represents the hot end of the heat pipe, and l represents the cold end of the heat pipe.
Representing the equivalent thermal conductivity of the heat pipe.
The first integral is the total heat exchange amount between the heat pipe and the flue gas along the axial direction of the heat pipe. Because the heat pipe plays the middle heat exchange effect, can't transfer the flue gas heat energy, so the heat transfer total amount on the heat pipe surface is 0, accords with the energy conservation.
Through the combination of the above formulas, relevant parameters such as the number of heat pipes, the nussel number and the like can be calculated.
The heat exchange performance of the structure can be estimated and whether the temperature uniformity requirement is met or not can be estimated according to the above types.
The above-mentioned structural heat exchange formula is a main improvement point of the present invention, and is an optimal heat exchange formula obtained through a large number of numerical simulations and experimental studies, and is not common knowledge in the art.
As an improvement, the heat pipe structure is further improved and optimized.
The inclination angle of the heat pipe and the horizontal plane is a. Through a large number of numerical simulations and experimental studies, it is found that the arrangement of the heat pipes 39 should take into consideration the flow distribution, mixing, resistance, vibration, ash discharge, etc. The tube spacing S of the heat pipe cannot be too small, otherwise, the flow resistance may be too large, the deposition may be easily generated, the deposition may not be too large, the temperature equalization effect may be deteriorated if the deposition is too large, the tube diameter d of the heat pipe may not be too large or too small, the heat transfer effect may be deteriorated or the flow resistance may be deteriorated, the inclination a of the heat pipe may not be too large or too small, the heat pipe may be too long if the deposition is too large, the backflow effect of the heat pipe may be deteriorated if the deposition is too small, and the heat exchange effect may be deteriorated.
Therefore, the parameters of the heat pipe are optimized, and an optimal design scheme is provided while the heat exchange effect is met.
Preferably, the relationship between the inclination angle a, the pipe diameter d and the pipe spacing S is as follows:
Sin(а)= b*(d/s)-f*(d/S)2-c, wherein b, c, f are parameters,
wherein 2.9315< f <2.9320,3.7648< b <3.7653,0.1820< c < 0.1825;
preferably, f =2.9318, b =3.765, c = 0.1822;
preferably, the angle of inclination a is 25-75 °.
Preferably, the tilt angle is 25 ° when the calculated tilt angle is less than 25 °, or Sin (a) <0 °, and 75 ° when the calculated tilt angle is greater than 75 ° or Sin (a) > 1.
Preferably, 0.187< d/S < 0.51;
preferably, the power of the single heat pipe is 800-;
preferably, 15< d <40 mm;
preferably, L =6000-10000mm
The center distance between adjacent heat pipes is 80< s <130 mm.
The optimal design requirements of the heat pipe can be met according to the types. The structural optimization formula is a main improvement point of the invention, is the most optimized formula which is researched by a large number of numerical simulations and experiments, and is not common knowledge in the field.
Although the present invention has been described with reference to the preferred embodiments, it is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (5)
1. A flue distributor utilizing heat pipes to equalize temperature is arranged between an air preheater and an economizer and is L-shaped, the distributor comprises a vertical part and a horizontal part, the vertical part is positioned at the upstream, the horizontal part is positioned at the downstream, the flue distributor is characterized in that the vertical part is provided with the heat pipes, the heat pipes extend from the bottom of one side wall of the vertical part to the other side wall of the vertical part, evaporation ends of the heat pipes are arranged on one side wall of the vertical part, condensation ends of the heat pipes are arranged on the other side wall of the vertical part, and the temperature of smoke at the evaporation ends of the heat pipes is higher than that of the smoke at the condensation ends of the heat pipes; the guide plates are arranged in the vertical part and are arranged on the upper part of the heat pipe, the guide plates are divided into two rows, and a space is arranged between every two adjacent guide plates in each row; the first row extends inwards from one side wall of the vertical part, the second row extends inwards from the other side of the vertical part, the interval between the guide plates of the first row is opposite to the guide plates of the second row, and the interval between the guide plates of the second row is opposite to the guide plates of the first row; the guide plate is arc-shaped; both the vertical and horizontal portions are rectangular in cross-section.
2. The flue distributor of claim 1 wherein the heat pipe extends obliquely upward from the evaporation end to the condensation end of the heat pipe.
3. The flue distributor of claim 1, wherein the condensing end is disposed above a middle portion of the other side wall.
4. The flue distributor of claim 1, wherein the condensing end is disposed above three-quarters of the height of the other side wall.
5. The flue distributor of claim 1 wherein the partial heat exchange within the flue distributor meets the following requirements:
wherein n represents the number of heat pipes, t represents the temperature, h represents the surface heat transfer coefficient,x represents the distance from the bottom of the heat pipe, L represents the length of the heat pipe,
which represents the coefficient of thermal conductivity of the material,
which represents the average incoming flow velocity of the fluid,
which is indicative of the density of the fluid,
represents the fluid viscosity, cp represents the fluid specific heat, d represents the heat pipe outer diameter; the subscript x represents the local value, f represents the fluid, w represents the wall, 0 represents the hot end of the heat pipe, l represents the cold end of the heat pipe,
representing the equivalent thermal conductivity of the heat pipe.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011093969.XA CN113137621B (en) | 2020-10-14 | 2020-10-14 | Flue distributor utilizing heat pipe for temperature equalization |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011093969.XA CN113137621B (en) | 2020-10-14 | 2020-10-14 | Flue distributor utilizing heat pipe for temperature equalization |
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| CN113137621A CN113137621A (en) | 2021-07-20 |
| CN113137621B true CN113137621B (en) | 2022-02-08 |
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Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH699393B1 (en) * | 2008-08-20 | 2012-02-15 | Eugen Gwerder | Heat exchangers for the flue of a furnace. |
| CN103267299A (en) * | 2013-05-26 | 2013-08-28 | 刘成红 | Composite type heat pipe waste heat recovery device |
| CN106765044B (en) * | 2017-01-03 | 2023-06-06 | 华电电力科学研究院 | System for power station boiler flue gas multichannel bypass waste heat grading utilization |
| JP6845711B2 (en) * | 2017-02-27 | 2021-03-24 | 三菱パワー株式会社 | Boiler duct structure, method for reducing solid particles contained in boiler and solid gas two-phase flow |
| CN207962700U (en) * | 2018-03-20 | 2018-10-12 | 国网安徽省电力公司电力科学研究院 | A kind of boiler SCR inlet smoke temperature regulating device based on hot pipe technique |
| CN110529872B (en) * | 2018-07-24 | 2020-11-17 | 苏州海陆重工股份有限公司 | Power station boiler waste heat utilization system based on inlet flue gas temperature communication control |
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