KR100635764B1 - Apparatus for preventing the heat exchange tube against erosion occurred in solid fuel fired system such as solid fuel fired incineration unit or boiler furnace using particle separation device - Google Patents

Abstract

An apparatus for preventing wear of a total heat pipe of a solid fuel burning unit using a mechanism separating pulverulent bodies in a gas is provided to remarkably extend the life span of equipment at a low cost by preventing wear of the total heat pipe by the collision of the pulverulent bodies. An apparatus for preventing wear of a total heat pipe of a solid fuel burning unit using a mechanism separating pulverulent bodies in a gas includes a flow deflecting plate(110) and a particle separating plate(120). The flow deflecting plate lessens the acceleration of exhaust gas and changes the direction of the flow to prevent deflection of the gas to a portion at which wear is expected. The flow deflecting plate flows the pulverulent bodies along an inclined surface. The particle separating plate introduces the pulverulent bodies flowing along the flow deflecting plate and induces the pulverulent bodies to an inner wall surface of an exhaust conduit.

Description

Apparatus for preventing the heat exchange tube against erosion occurred in solid fuel fired system such as solid fuel fired incineration unit or boiler furnace using particle separation device}

1 is a schematic diagram showing the structure of a typical boiler.

FIG. 2 is a perspective view showing the actual shape of the superheater and the cutting machine of FIG. 1.

3 is a cross-sectional view of a heat pipe showing one example of a wear preventing means of a conventional heat pipe.

Figure 4 is a schematic view showing another example of the wear protection means of the conventional heat pipe.

5a and 5b show the configuration of the heat pipe wear protection device according to the invention, Figure 5a is a longitudinal cross-sectional view, Figure 5b is a cross-sectional view.

Figure 6 is a front sectional view for explaining the flow mode of the exhaust gas and powder (fly ash) when the heat pipe wear protection device according to the present invention is applied.

7 is a view showing the wear protection means of the heat transfer tube according to another embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10: combustion furnace 12: water pipe wall

14: rear year 14a: inner wall surface of the year

16: heat pipe 16a: bent portion

20: superheater 20a: heat pipe group (君)

30: pelletizer 40: air preheater

50: wear protection plate 60: drift prevention plate

100 powder separation mechanism 110 flow deflection plate

120: particle separation plate 130: remixing prevention plate

131: vent 140: extension

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus for combusting solid fuels such as power generation boilers, cogeneration boilers, incinerators, and the like, and more particularly, to separate powders containing ash in the combustion gas and to separate the flow thereof. By preventing the heat pipe from abrasion due to the collision of the powder by bypassing the heat pipe, it prevents the heat pipe wear of the solid fuel combustion device using a mechanism that separates the powder in the gas, which can significantly extend the life of the equipment at low cost. Relates to a device.

The solid fuel combustion device in the present specification mainly refers to a power generation boiler, a cogeneration boiler, an incinerator, or the like, which burns a solid fuel such as coal to generate steam at a high temperature and pressure.

In the accompanying drawings, one configuration example of such a solid fuel combustion device is shown. As shown in FIG. 1, solid fuel such as coal is combusted in a combustion furnace 10, which is enclosed by a water pipe wall 12 (or a water cooling wall), and thus the inside of the water pipe wall 12 may be burned. The flowing water is heated to produce steam. Combustion gas exits the rear flue 14 through the upper part of the combustion furnace 10, and is equipped with a reheater or superheater 20, and an economizer 30, which are installed in the rear flue 14, and It is discharged to the stack (not shown) via the air preheater 40.

Ash, which is powder, is generated in the process of burning solid fuel in the combustion furnace 10, which is classified into bottom ash and fly ash. The double bottom ash falls to the lower part of the combustion furnace 10 and is collected in a low ash treatment tank (not shown). The fly ash is mixed with the combustion gas and flows through the upper portion of the combustion furnace 10 and flows out to the rear flue 14. Next, it is collected by a dust collector (not shown) or the like.

Here, the rear part heat exchange tube bundles 20a, such as the reheater or superheater 20 or the pelletizer 30, are orthogonal to the flow of combustion gas in a direction crossing the rear flue 14. It is arrange | positioned in the direction to make, and maintains the constant clearance gap with the inner wall surface of the rear edge flue 14.

Since the heat pipes of this rear heat pipe group 20a are exposed to a wide variety of serious hazards, this becomes an important component in determining the life of the combustion device. Therefore, the heat transfer tube is designed to have strength to withstand the temperature of the combustion gas and the internal vapor pressure, and the outer surface of the heat transfer tube is designed to have corrosion resistance and wear resistance to powders such as combustion gases and non-ash particles.

One of the serious causes of damaging the heat pipes is a phenomenon in which the powder generated by the combustion of the solid fuel collides with the heat pipe surfaces and wears down the surface of the heat pipes. The site where the abrasion caused by the collision of the fly ash occurs most seriously is the heat transfer tube and the right and left sides of the heat transfer tube forming the uppermost portion of the heat transfer tube group 20a arranged to cross the inside of the rear flue 14 to counter the flow of the combustion gas. It is around a bend, a soot blower (not shown), and a gas drift generation part.

That is, in FIG. 1, the regions R indicated by dotted circles in the reheater or superheater 20 and the carburettor 30 are areas where breakage occurs frequently due to wear caused by collisions of fly ash. The fraud zones R are areas where severe drift occurs adjacent to the inner wall surface of the rear flue 14, where the combustion gas passes locally through a narrow cross-sectional area, so-called 'channel effect'. 'Occurs. Therefore, the non-ash particles (powder) in the combustion gas collide with the region R with a very strong force to promote wear of the heat transfer tube surface.

Figure 2 shows the actual form of the reheater or superheater 20 and the cutter machine 30 described above. The reheater or superheater 20 and the pelletizer 30 are configured by bending a plurality of heat pipes 16 a single bundle. Here, it can be seen that the region R, which is prone to abrasion due to the strong force of the powder due to the acceleration of the combustion gas due to the channel effect, is mainly a bent portion of the heat transfer tube.

Conventional means for preventing wear of such heat pipes are illustrated in the accompanying drawings, FIGS. 3 and 4.

First, the conventional example shown in FIG. 3 is to attach a wear prevention plate 50 (Tube Shield) to the surface of the heat transfer tube 16 that is expected to be worn by the powder, that is, the surface facing the flow direction of the combustion gas. . According to this method, the heat shield tube 16 is protected by preventing the powder from being blocked by the wear preventing plate 50 and directly colliding with the heat transfer tube 16. However, the use of the anti-wear plate 50 is not a permanent countermeasure, and the phenomenon in which the acceleration region of the combustion gas is generated due to the channel effect cannot be cured. Therefore, sufficient heat exchange time in this portion is secured. Can't.

In the example shown in FIG. 4, the anti-drift plate 60 is formed between the portion where local acceleration occurs due to the channel effect, that is, the bent portion 16a of the heat transfer pipe 16 and the inner wall surface 14a of the flue 14. , Baffle Plate) is installed. According to this method, the flow of combustion gas to the bent portion 16a of the heat transfer tube 16 is blocked by the drift preventing plate 60, so that the phenomenon of powder approaching the bent portion 16a of the heat transfer tube 16 is prevented. It is blocked at the source. However, according to this method, there is no so-called 'dead zone' where no heat exchange occurs due to no flow of combustion gas between the drift preventing plate 60 and the inner wall surface 14a of the flue 14. Overall, this results in a decrease in heat transfer area. In order to compensate for the reduction in heat transfer area, additional heat transfer tubes have to be additionally disposed, which increases the installation cost.

In addition to the methods described above, a method of homogenizing the flow of the combustion gas may be used by arranging a perforated plate or a steel mesh across the entire cross section of the rear flue 14. However, in such a method, the pressure loss generated by the perforated plate or the wire mesh is excessively increased to reduce the thermal efficiency, and the structure of the year is difficult and expensive because a large structure (perforated plate or the wire mesh) must be installed in the year. This has the disadvantage of being excessively increased. In addition, if the gas flow in the flue changes due to a change in load, a change in coal type, or the like, the overall efficiency of the combustion device is deteriorated when the initial condition is out of the design conditions for the perforated plate or the wire mesh. In addition, the porous plate or the wire mesh is installed over the entire cross-section of the flue has the disadvantage of increasing the weight of the structure.

The present invention has been developed to solve the above conventional problems. The object of the present invention is to prevent the wear of the heat transfer tubes due to the collision of the powders by separating the powder containing the ash particles from the combustion gas and diverting its flow out of the heat transfer tubes and at the same time reducing the flow rate of the equipment. It is to be able to extend.

In order to achieve the above object, in the present invention, a group of heat transfer tubes such as a reheater, a superheater, or a cutener installed in a rear flue of a combustion device such as a power generation boiler, a cogeneration boiler, an incinerator, etc., using a solid fuel, An apparatus for preventing abrasion due to collision of powder including fly ash, the device being inclined downward from the inner wall surface of the flue toward the center of the flue on an upstream side of a local acceleration predicted region where wear of the heat transfer tube group is expected. It is installed extending from one end of the inner wall to the opposite end, to reduce the acceleration of the combustion gas and to change the flow direction to prevent the combustion gas from biasing to the anticipated wear site, while the combustion gas is hit, A flow deflecting plate for causing the powder containing fly ash present in the combustion gas to strike and flow down the slope; On the downstream side of the front end of the flow deflection plate, the flow deflection plate is disposed in a shape inclined in a direction opposite to the inclination direction of the flow deflection plate, the upper end portion of which is maintained at a constant distance from the front end of the flow deflection plate between the flow deflection plates. Preventing the heat transfer tube wear of the solid fuel combustion apparatus using a mechanism for separating the powder in the gas, characterized in that it comprises a particle separator for flowing the powder flowing down along the flow induces closer to the inner wall surface side of the flue flows downstream An apparatus is provided.

In the present invention described above, the flow deflection plate may be made of a porous plate formed with a plurality of fine holes in the plate.

In the present invention described above, the flow deflection plate may be made of a wire mesh form having a mesh of fine size.

In the present invention described above, the inside of the particle separation plate, extends downward from the particle separation plate to a point adjacent to the upper portion of the heat pipe group, intercepting the middle portion of the year and the local acceleration expected region, By reducing the amount and velocity of combustion gas flowing from the middle portion into the local acceleration prediction region, the velocity is high in the powder separated by the flow deflecting plate and particle separator and flowing slowly along the inner wall of the flue. A remixing prevention plate may be further installed to prevent the combustion gases from mixing again.

In the present invention described above, the re-mixing separator, it may be formed in the form of a plurality of fine vent holes.

Alternatively, the remixed separator may be formed in the form of a wire mesh having a fine mesh.

Extends from the lower end of the particle separator to the inlet of the region where local acceleration is expected between the upper bent portion of the heat pipe group and the inner wall surface of the flue, separated by the flow deflection plate and the particle separator at a slow speed By further adhering the flowing powder to the inner wall surface side of the flue, it may further include an extension plate that serves to further reduce the number of powder hit the heat pipe group.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, FIGS. 5A, 5B, and 6.

5A and 5B show a configuration of a heat pipe wear protection device according to the present invention. FIG. 5A shows a longitudinal cross-sectional view and FIG. 5B shows a cross-sectional view (flat cross-sectional view).

5a and 5b, the present invention relates to the localization of the combustion gas by means of the clearance d between the side end of the heat transfer tube group 20a, such as a reheater or superheater or an opener, and the inner wall surface 14a of the flue 14. The heat transfer pipe 16 constituting the heat transfer pipe group 20a to reduce the speed of the powder containing fly ash on the upstream side of the region where acceleration occurs (hereinafter referred to as a "local acceleration zone" or "local acceleration acceleration zone"). It is provided with a powder separation mechanism 100 for reducing the amount of powder hitting the bent portion (16a) of.

Specifically, the powder separation mechanism 100 basically includes a flow deflection plate 110 and a particle separation plate 120.

The flow deflection plate 110 is downward from the inner wall surface 14a of the flue 14 toward the center of the flue 14 upstream of the local acceleration region A where wear of the heat transfer tube group 20a is expected. It is installed from one end of the inner wall surface 14a to the opposite end in an inclined form. This flow deflection plate 110 mitigates the acceleration of the combustion gas and changes the flow direction to prevent the combustion gas from biasing to the anticipated wear site. In addition, when the combustion gas collides, it plays a role of causing the powder such as fly ash present in the combustion gas to collide and flow down the inclined surface. The flow deflection plate 110 may use any structure as long as it is an inclined structure capable of deflecting a constant flow of the combustion gas. For example, it may be made of a general plate without any vents, may be made of a porous plate having a plurality of fine holes formed in the plate, or may be made of a wire mesh having a fine mesh. .

The particle separation plate 120 is disposed in a form inclined in a direction opposite to the inclination direction of the flow deflection plate 110 on the downstream side of the front end portion of the flow deflection plate 110. The particle separation plate 120, the upper end portion thereof is maintained at a constant distance from the front end of the flow deflection plate 110, the powder impinging on the flow deflection plate 110 between the gaps inflow of the flue 14 It guides closer to the inner wall surface 14a and serves to flow downstream.

In the present invention, the inner side of the particle separation plate 120, that is, the center of the flue 14, the re-mixing extending downward from the particle separation plate 120 to a point adjacent to the upper portion of the heat pipe group (20a) The prevention plate 130 may be further provided. The re-mixing separator 130 blocks a portion of the middle portion of the flue 14 and the local acceleration region A by a portion, and the combustion gas flows into the local acceleration region A from the middle portion of the flue 14. It reduces the amount and speed of Therefore, it is separated by the flow deflection plate 110 and the particle separation plate 120, the combustion gas having a high speed is mixed again with the powder flowing down at a slow speed along the inner wall surface 14a of the flue (14). Will be prevented. The re-mixing prevention plate 130 is preferably made of a porous plate having a plurality of fine vent holes 131 formed on the plate, or a wire mesh having a fine mesh. According to this structure, the flow of the combustion gas to some extent is maintained while blocking the inflow of excessively large amount of combustion gas, so that the powder coming down through the powder separation plate 120 to the inner wall surface of the flue (14) Proximity to 14a.

6 is a view for explaining the flow of the combustion gas and powder by the heat pipe wear protection device 100 of the present invention made as described above.

The heat pipe wear protection device according to the present invention is based on the fact that the wear of the heat pipe by the powder containing fly ash is promoted in proportion to the amount of powder and in proportion to the square of the speed of the powder. Therefore, it is intended to significantly prevent wear of the heat transfer pipe located in the local acceleration region of the combustion gas by slowing down the flow of the combustion gas in the region where local acceleration is expected and bypassing the powder.

As shown in FIG. 6, the combustion gas including the powder flowing down from the upstream of the local acceleration region A hits the flow deflection plate 110 and the direction of flow is indicated by the arrow (black thick arrow) direction. Will change to When the combustion gas hits the flow deflection plate 110, the powders P present in the combustion gas also hit the flow deflection plate 110. However, most of the powders (P) hit the flow deflection plate 110 does not follow the speed of the combustion gas that changes the direction of the flow rapidly by its inertial force is hit by the flow deflection plate 110 flows down the slope. .

When the flow deflection plate 110 is made of a porous plate having a fine hole or a wire mesh having a fine mesh, most of the combustion gas hits the flow deflection plate 110 and most of the flow direction is changed, but only a part of the combustion The gas passes through the fine holes or the fine mesh of the porous plate. As such, when the minimum flow of the combustion gas is ensured through the fine holes or the mesh of the flow deflection plate 110, more powders P are accumulated on the surface of the flow deflection plate 110 by its suction force, and some fine powder is present. (P) may pass through the micropores or meshes.

The powders P flowing down to the front end thereof along the inclined surface of the flow deflecting plate 110 collide with the upper end of the particle separating plate 120, and then the front end of the flow deflecting plate 110 and the particle separating plate 120. It descends through the gap between the upper end of the) and flows down along the inclined surface of the particle separator (120). Here, since the particle separator 120 is inclined toward the inner wall surface 14a of the flue 14, the powders P are guided in a direction close to the inner wall surface 14a of the flue 14.

The powders P passing through the particle separator 120 to the region A where local acceleration is expected are affected by the velocity of the combustion gas flowing through the middle portion of the flue 14. However, the combustion gas flowing in the middle portion of the flue 14 is blocked by the remixing prevention plate 130. For this reason, only a small part of the combustion gas flowing in the middle portion of the flue 14 flows in at a reduced speed through the fine vent 131 of the remixing prevention plate 130. Accordingly, the velocity of the combustion gas including the powders P passing through the particle separation plate 120 is maintained at a rate significantly lower than the velocity of the combustion gas flowing through the middle portion of the flue 14. It flows downstream through the gap d between the bent portion 16a and the inner wall surface 14a of the flue 14.

As described above, according to the powder separation mechanism 100 according to the present invention, the velocity of the combustion gas passing through the region A in which local acceleration is expected to drop significantly, and many individuals of the powders P flowing through the flue 14 are reduced. And flows downstream to the inner wall surface 14a of the flue 14 and flows downstream with the combustion gas which is significantly lowered in velocity, thereby significantly reducing wear and damage of the heat transfer tube group 20a caused by the collision of the powder P. You can do it.

FIG. 7 shows another embodiment of the powder separation mechanism 100 according to the present invention.

The powder separation mechanism 100 shown in FIG. 7 includes an extension plate 140 extending downward from the lower end of the particle separation plate 120 in the powder separation mechanism 100 described above with reference to FIGS. 5A, 5B and 6. It has a more installed configuration. The rest of the configuration is the same as in the described embodiment.

The extension plate 140 is located between the upper bent portion 16a of the heat pipe group 20a and the inner wall surface 14a of the flue 14 from the particle separator 120, that is, the region A where local acceleration is expected. It has a form extending to the entrance portion of. Here, the extension plate 140 may be a form in which the particle separation plate 120 is integrally extended, or may be separately manufactured and then bonded to the particle separation plate 120 by welding or the like.

The extension plate 140 is separated by the flow deflection plate 110 and the particle separation plate 120 to further adhere the powder P flowing at a slow speed toward the inner wall surface 14a side of the flue 14. By doing so, the number of the powders P striking (bumping) on the heat pipe group 20a serves to further reduce the wear of the heat pipe 16. In addition, the speed of the combustion gas passing through the channel portion of the powder P, that is, the gap d, is further reduced by being less affected by the speed of the combustion gas flowing from the remixing prevention plate 130.

In addition, in the powder separation mechanism in which the said extension plate 140 was further provided, it is not necessary to provide the re-mixing prevention plate 130 mentioned above. This is because the influence of the velocity of the combustion gas flowing in the flue 140 on the powder P by the extension plate 140 can be reduced. Therefore, only one of them may be provided or both may be provided depending on the size of the solid combustion apparatus, the operating temperature, the cross-sectional area of the flue 14, the speed of the combustion gas, the type of the solid fuel, and the like.

Although specific embodiments of the present invention shown in the accompanying drawings have been described in detail above, this is merely an example of a preferred embodiment, and the protection scope of the present invention is not limited thereto. In addition, the embodiments of the present invention as described above can be variously modified and equivalent other embodiments by those of ordinary skill in the art within the technical spirit of the present invention, such modifications and equivalent other embodiments are It goes without saying that it belongs to the appended claims of the invention.

As described above, in the present invention, the combustion gas and the powder (including fly ash) are deflected by using a flow deflection plate that can change the flow of the combustion gas at the upper portion of the local acceleration region where wear of the heat transfer tube group is expected. The combustion gas and the powder are separated and sent downstream using a particle separator considering the inertial force of the powder. In addition, it is possible to prevent the phenomenon in which the heat transfer tube group is worn by the high-speed collision of the powder in the combustion gas by drastically lowering the speed of the combustion gas in the region where local acceleration is expected by the above components. .

In addition, the apparatus of the present invention as described above has a simple structure and is provided to be limited to one side portion of the year, and because it does not cover the entire year, the increase in cost is never burdensome compared to the obtainable effect. Will not.

Claims (7)

Prevents abrasion due to powders including fly ashes of heat pipe groups such as reheaters, superheaters, or cutters installed in the rear year of combustion devices such as power generation boilers, cogeneration boilers, and incinerators using solid fuels. As a device for Extends from one end of the inner wall surface to the opposite end in an inclined downward direction from the inner wall surface of the flue toward the center of the flue on an upstream side of a local acceleration predicted region where wear of the heat pipe group is expected, The acceleration of the combustion gas is alleviated and the flow direction is changed to prevent the combustion gas from being biased toward the anticipated wear site, while when the combustion gas strikes, powders containing fly ash present in the combustion gas collide and flow down the slope. A flow deflection plate to lower; On the downstream side of the front end of the flow deflection plate, the flow deflection plate is disposed in a shape inclined in a direction opposite to the inclination direction of the flow deflection plate, the upper end portion of which is maintained at a constant distance from the front end of the flow deflection plate between the flow deflection plates. Preventing the heat transfer tube wear of the solid fuel combustion apparatus using a mechanism for separating the powder in the gas, characterized in that it comprises a particle separator for flowing the powder flowing down along the flow induces closer to the inner wall surface side of the flue flows downstream Device. The method of claim 1, The flow deflection plate is made of a porous plate having a plurality of fine holes formed in the plate, characterized in that the heat pipe wear prevention device of the solid fuel combustion device using a mechanism for separating the powder in the gas. The method of claim 1, The flow deflecting plate is a wire mesh wear prevention device of a solid fuel combustion device using a mechanism for separating the powder in the gas, characterized in that formed in the form of a wire mesh having a fine mesh. The method of claim 1, Inside the particle separator, it extends downward from the particle separator to a point adjacent to the upper portion of the heat pipe group, intercepting the middle portion of the year and the local acceleration prediction region, and predicting the local acceleration from the middle portion of the year. By reducing the amount and speed of the combustion gas flowing into the zone, the high velocity combustion gas is again mixed with the powder separated by the flow deflection plate and the particle separation plate and flowing down at a slow speed along the inner wall of the flue. Heat exchanger tube wear prevention device of a solid fuel combustion device using a mechanism for separating the powder in the gas, characterized in that the re-mixing prevention plate to prevent further. The method of claim 4, wherein The re-mixing separator is a heat exchange tube wear protection device of a solid fuel combustion device using a mechanism for separating the powder in the gas, characterized in that the form of a plurality of fine vent holes formed. The method of claim 4, wherein The re-mixing separator is in the form of a wire mesh having a fine mesh (mesh) characterized in that the heat pipe wear prevention device of the solid fuel combustion device using a mechanism for separating the powder in the gas. The method according to claim 1 or 4, Extends from the lower end of the particle separator to the inlet of the region where local acceleration is expected between the upper bent portion of the heat pipe group and the inner wall surface of the flue, separated by the flow deflection plate and the particle separator at a slow speed By further adhering the flowing powder to the inner wall surface side of the flue, further comprising an extension plate that serves to further reduce the number of powder hit by the heat pipe group, solid fuel using a mechanism for separating the powder in the gas Heat pipe wear protection device of combustion device.

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