JP5079465B2 - Shot cleaning device and shot ball collecting method of shot cleaning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shot cleaning device and a shot ball recovering method capable of uniformly spreading shot balls to the entire heat transfer tubes with a very simple device without using a complicated distributor relating to conventional technology, and being applied to an evaporator and a superheater exchanging heat with a high-temperature gas. <P>SOLUTION: In this shot cleaning device spreading the shot balls from an upper portion of the group of heat transfer tubes for knocking off dust attached to the group of horizontal heat transfer tubes recovering heat from an exhaust gas by drop collision of shot balls, the shot balls are jetted from the upper portion of the group of heat transfer tubes by pneumatic carrying, and a collision plate is disposed to allow the jetted shot balls to collide with the plate to be dispersed. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a shot cleaning device and a shot sphere, in which dust adhered to the heat transfer tube surface of a heat exchanger disposed in an exhaust gas flow path of a boiler is removed by colliding the shot sphere by falling and colliding with the shot sphere. A shot cleaning device and a shot capable of removing dust adhering to a heat transfer tube group of a boiler by spraying shot spheres uniformly over the entire heat transfer tube in spite of a particularly simple device configuration regarding the recovery method The present invention relates to a method for collecting balls.

  If dust adheres to the surface of the heat exchanger tube of the heat exchanger disposed in the exhaust gas flow path of the boiler, the heat recovery efficiency of the heat exchanger is reduced, and thus it is necessary to periodically remove the attached dust. Conventionally, a soot blow system in which steam generated from a boiler is sprayed onto a heat transfer tube to remove dust from the heat transfer tube formed of a horizontal tube group is generally used. In this system, the strength of the wiping off is generated depending on the distance of the heat transfer tube from the soot blow and the position in the heat transfer tube group. That is, the dust attached to the surface of the heat transfer tube group is removed by the strong injection force on the surface of the heat transfer tube group on the soot blow injection nozzle side, but the injection force is weakened on the inner side of the heat transfer tube group and the dust removal performance is lowered. There was a problem. For this reason, it is necessary to install a large number of soot blowers in the height direction, and the cost for installation has been great. Further, the surface heat transfer tube group on the injection nozzle side has a problem that the heat transfer tube group is worn because the injection force is strong.

  Further, since steam generated in the boiler is used as the injection fluid, the amount of recovered steam is reduced at the time of soot blow, and in particular when the power is generated by the steam turbine, the generated power is reduced.

  FIG. 5 shows an example in which a soot blow type dust removing device is installed in a waste heat boiler. In FIG. 5, high-temperature exhaust gas is cooled in the radiation cooling chamber 1a, enters the adjacent chamber from the lower part of the boiler, exchanges heat through the superheater 1b, the evaporator 1c, and the economizer 1d, and is discharged from the upper part of the boiler. Each of these heat exchangers is composed of a horizontal heat transfer tube group.

  A number of soot blows 1g are provided to remove dust adhering to and accumulated on these heat transfer tube groups, a steam injection hole for injecting the probe in the direction perpendicular to the probe is provided at the tip of the probe, and the probe rotates and advances and retreats. It is injected into the heat transfer tube by operation. The soot blow is an intermittent operation, and the dust settles downward and is discharged out of the boiler from the dust discharge device 1f.

  In the case of this soot blow method, the heat transfer tube near the nozzle side, especially the heat transfer tube on the surface side, receives a strong injection force, and the dust removal effect is obtained. It becomes weaker and the dust removal ability is reduced. For this reason, the pressure of the injection force is increased to ensure a sufficient dust wiping force for the heat transfer tube on the back side, but this results in the wear of the heat transfer tube on the surface side.

  Further, in the soot blow system, it is common to use boiler steam as the jet fluid, but since steam of 1 to 2 ton / hour is used as the amount of steam, the amount of heat recovered from the boiler is reduced. .

  In contrast to this soot blow system, a system in which steel balls are dispersed from the upper part of the heat exchanger as disclosed in Patent Document 1 has been conventionally employed. This is shown in FIG. In FIG. 6, the steel ball collides with the heat transfer tube group in the process of falling through the economizer 1d, falls down while dust is removed, and the steel ball that falls with the dust is separated into a dust steel ball separator by the screw conveyor 1f. The dust and steel balls are separated and collected. The collected steel balls are sent to the steel ball storage tank 14 by a bucket conveyor, and are sprayed again from the upper part of the heat transfer tube group via the steel ball distributor 12.

FIG. 7 shows a dispersion apparatus disclosed in Patent Document 2. In FIG. 7, the steel ball entered from the steel ball inlet 12b enters the steel ball receiver 12e that is partitioned in the circumferential direction by the turning chute 12a that is turned by the rotation drive device 12c, and is determined by the corresponding distribution pipe 12d. Drop to the position of the heat transfer tube group. A large number of distribution pipes 12d are provided, and each distribution pipe 12d is sequentially supplied by a turning chute 12a so that uniform distribution can be performed. As described above, the conventional steel ball distribution device has a complicated structure, and this complicated steel ball distribution device needs to be included in the boiler casing, which requires a large space. Furthermore, since this apparatus is made of a metal mainly composed of a steel plate, there are significant restrictions on the gas temperature conditions, and only heat exchangers cooled to 350 ° C. or less by the boiler body are targeted. There is a problem that it cannot be used in an evaporator or a superheater that exchanges heat with a hot gas.
JP 2002-81849 A JP-A-7-63494

  The problem to be solved by the present invention is an evaporator or superheater that can be uniformly distributed over the entire heat transfer tube with a very simple device without using a complicated distributor according to the prior art, and that exchanges heat with a hot gas. It is another object of the present invention to provide a shot cleaning device and a method of collecting shot balls that are possible.

(1) Dust adhering to the horizontal heat transfer tube group of the boiler that recovers heat from the exhaust gas is sprayed from the upper part of the heat transfer tube group, and the dust adhering to the heat transfer tube group by the falling collision of the shot ball is removed. In the shot cleaning device to be wiped out,
A shot sphere ejection nozzle that is installed above the heat transfer tube group and ejects a shot sphere in a horizontal direction;
Collision plate axis provided above the shot ball ejection nozzle and horizontally disposed so as to be orthogonal to the shot ball ejection direction;
Collision plate capable of tilting about the collision plate axis and having a collision surface facing the shot ball ejection nozzle on the collision plate axis and causing the shot sphere ejected from the shot ball ejection nozzle to collide with the collision surface With
When the collision plate is in a standing state with the angle θ with respect to the vertical direction of the collision plate being reduced, the collided shot ball is dropped to the side closer to the shot ball ejection nozzle, and the θ is increased to When lying down, so that the shot ball that collided falls to the far side of the shot ball ejection nozzle,
The angle of the collision plate with respect to the vertical direction is changed to control the distribution of the ejection direction, whereby the shot sphere ejected in the horizontal direction from the shot sphere ejection nozzle is uniformly dispersed throughout the heat transfer tube group. A shot cleaning device.

(2) Dust adhering to the horizontal heat transfer tube group of the boiler that recovers heat from the exhaust gas is scattered from the upper part of the heat transfer tube group, and the dust adhering to the heat transfer tube group due to the falling collision of the shot ball is removed. In the shot cleaning method,
A collision plate that collides with a shot sphere ejected in a horizontal direction from a shot sphere ejection nozzle installed above the heat transfer tube group, and above the shot sphere ejection nozzle so as to be orthogonal to the ejection direction of the shot sphere. provided, the angle between the vertical impingement plate provided in the tiltable said collision plate shaft impact plate axis that is horizontally disposed as an axis,
When the collision plate is upright with the angle θ decreased, the collided shot ball is dropped to the side close to the shot ball ejection nozzle, and when the θ is increased and the collision plate is laid down, The shot sphere is changed so that the shot sphere is dropped to the far side of the shot sphere ejection nozzle, and the distribution in the ejection direction is controlled, whereby the shot sphere ejected in the horizontal direction from the shot sphere ejection nozzle is changed to the entire heat transfer tube group. A shot cleaning method characterized by uniformly dispersing in the above.

  Although the shot cleaning device of the present invention has a simple configuration, it can scatter shot spheres over the entire heat transfer tube group, and can uniformly remove dust adhering to the heat transfer tube group. In addition, in order to have a steel plate dispersing device in the boiler casing, the boiler gas flow is an upward flow, and it is installed under a gas temperature condition that is sufficiently cooled by passing through the heat transfer tube. We were able to solve the problem of heat resistance. Moreover, since the collision plate is only installed in the boiler casing, the casing is compact, so that the equipment cost can be greatly reduced and the maintainability is improved.

FIG. 1 shows an embodiment of the present invention. For example, the high-temperature gas obtained by burning the waste becomes 900 ° C. to 1000 ° C., and the boiler 1 recovers heat.
The hot gas is cooled in the radiant cooling chamber 1a in the boiler 1, reversed in the lower part of the boiler, and discharged from the boiler as exhaust gas after heat recovery from the upper part through the superheater 1b, the evaporator 1c, and the economizer 1d.
A collision type shot ball dispersion device 2 is provided above the uppermost economizer 1d. The shot ball 10 sent by the air current conveyance is directly ejected from the shot ball ejection nozzle 3 into the boiler. The shot ball 10 ejected collides with the collision plate 2a and falls onto the top of the economizer 1d.

In this case, as shown in FIG. 2, the collision plate 2a is provided with a collision plate shaft 2c which is a horizontal rotation axis so as to be orthogonal to the shot ball ejection direction, and the collision plate 2a is provided with the collision plate 2a. . A motor 2b is connected to one end side of the collision plate shaft 2c, and the collision plate 2a can be tilted by the motor 2b. In other words, the collision angle of the collision plate 2a is made variable by the motor 2b about the collision plate axis 2c.
As shown in FIG. 3A, the shot sphere 10 ejected from the shot sphere ejection nozzle 3 collides with the collision plate 2a and is dispersed and dropped in the economizer 1d. By tilting the collision plate 2a, dispersion in the ejection direction becomes uniform.

Further, as shown in FIG. 3B, by making the collision surface of the collision plate 2a a convex or convex curved surface, it is possible to obtain a shot sphere 10 distribution having a spread. FIG. 3B is a cross-sectional view taken along the line BB in FIG.
FIG. 4 is a distribution diagram showing a dispersion state of shot spheres when the collision surface of the collision plate 2a is a flat surface and when the collision surface is a polygonal surface, and when the collision surface is a polygonal surface or a convex surface, Distribution is improved. Further, when the shot sphere 10 is caused to collide while the collision plate 2a is tilted, the distribution of the discharge direction of the shot sphere can be controlled and can be freely distributed as a whole. Furthermore, since this apparatus is installed in the upper part of the boiler by making the exhaust gas flow upward, the exhaust gas temperature at the outlet of the economizer 1d is about 200 to 250 ° C., and the problem of heat resistance of the apparatus itself is Absent. If the flow of the exhaust gas passing through the horizontal heat transfer tube group is an upward flow, the shot sphere falls opposite to this.

The shot balls 10 sprayed on the upper part of the economizer 1d pass through the economizer 1d, the evaporator 1c, and the superheater 1b, and are collected in the lower part of the boiler together with the dust that has been removed. In the lower part of the boiler, dust and shot balls are stored in the shot ball storage tank 5. Since the dust and shot ball storage tank 5 is connected to the boiler casing via the chute 1h, it is not directly exposed to the exhaust gas flow. Thus, it is desirable that the storage tank 5 installed at the lower part of the horizontal heat transfer tube group is disposed at a position not affected by heat transfer from the exhaust gas passing through the lower part of the boiler.
Moreover, since high temperature dust and shot balls are stored in the dust and shot ball storage tank 5, cooling air is introduced from the outside. Thus, it is desirable to provide the storage tank 5 with a cooling gas blowing device for blowing the accumulated dust and the gas for cooling the shot sphere.

As an example, when the shot sphere φ6.3 mm is dispersed from the upper part of the economizer, it passes through the shot sphere, which collides with the collision plate, falls into the heat transfer tube group and is collected in the storage tank 5. The time was 10 seconds or less, and it was confirmed that the temperature of the shot sphere was within about 200 ° C., and there was no problem with heat resistance.
Next, the dust 11 and the shot sphere 10 cooled in the storage tank 5 are collected in the shot sphere storage tank 7 by collecting the shot sphere 10 by the vibration sieve type dust and the shot sphere separator 6 through the discharge device 5a. Wait until the next cleaning starts.

  When the next cut-out time comes, a fixed amount is cut out from the shot ball storage tank 7 by the cut-out device 7 a, and at the same time, the transfer air valve 9 is opened and the air flow is transferred by the injector 8. In this case, the shot sphere φ6.3 mm is conveyed at a flow rate of 40 m / s. Further, although a steel ball is used as the shot ball, if a ceramic ball having a light specific gravity compared to the steel ball is used, the conveying wind speed can be reduced and the conveying energy can be reduced.

  Further, in the shot cleaning method using steel balls, the staggered arrangement of the heat transfer tubes shown in FIG. 8B has a higher dust removal performance than the square arrangement shown in FIG.

  In order to confirm the classification effect of this apparatus, next, a test was carried out with the dispersion effect of the shot ball 10 on the upper part of the economizer 1d. As a result of investigating the distribution in the direction perpendicular to the ejection direction of the shot ball ejection nozzle 3, the test results showing the relationship between the collision plate 2a and the shape of the collision surface are shown in FIG. FIG. 4 (a) is a test apparatus, and the test was performed according to a similar law with the same Froude number at approximately 1/5 scale. A receptacle was installed under the heat transfer tube group, and the weight distribution of each receptacle was investigated. When the collision plate is a flat plate as shown in (b), it drops in a concentrated manner in the center, but it is confirmed that a substantially uniform distribution can be obtained when it is slightly polygonal as shown in (c). Further, the distribution in the ejection direction can be freely controlled by changing the angle θ of the collision plate in (a). From this experiment, it was confirmed that it could be distributed uniformly over the entire surface of the heat transfer tube.

It is a schematic block diagram of the shot cleaning apparatus which shows one Example of this invention. It is AA sectional drawing of FIG. It is the schematic of the collision board of this invention. This is a test device for confirming the distribution effect by the collision plate. It is the schematic which shows the dust removal system of the conventional system. This is a conventional dust removing device using a shot cleaning system. It is a conventional dispensing device. It is a layout of a heat transfer tube group.

Explanation of symbols

1 boiler casing 1a radiant cooling chamber 1b superheater 1c evaporator 1d economizer 1e boiler feed tank 1f screw conveyor 1g soot blow 2 shot ball dispersion device 2a collision plate 2b motor 2c collision plate shaft 3 shot ball ejection nozzle 4 shot ball transport path DESCRIPTION OF SYMBOLS 5 Storage tank 5a Discharge device 6 Separation device 7 Shot ball storage tank 7a Shot ball cutting device 8 Injector 9 Carrying air valve 10 Shot ball 11 Dust 12 Steel ball distributor 12a Turning chute 12b Steel ball inlet 12c Rotation drive device 12d Distribution pipe 12e Steel ball receiver 13 Steel ball disperser 14 Steel ball storage tank

Claims (2)

A shot in which dust adhered to the horizontal heat transfer tube group of the boiler that recovers heat from the exhaust gas is scattered from the upper part of the heat transfer tube group, and the dust adhering to the heat transfer tube group is removed by the falling collision of the shot ball. In the cleaning device,
A shot sphere ejection nozzle that is installed above the heat transfer tube group and ejects a shot sphere in a horizontal direction;
Collision plate axis provided above the shot ball ejection nozzle and horizontally disposed so as to be orthogonal to the shot ball ejection direction;
Collision plate capable of tilting about the collision plate axis and having a collision surface facing the shot ball ejection nozzle on the collision plate axis and causing the shot sphere ejected from the shot ball ejection nozzle to collide with the collision surface With
When the collision plate is in a standing state with the angle θ with respect to the vertical direction of the collision plate being reduced, the collided shot ball is dropped to the side closer to the shot ball ejection nozzle, and the θ is increased to When lying down, so that the shot ball that collided falls to the far side of the shot ball ejection nozzle,
The angle of the collision plate with respect to the vertical direction is changed to control the distribution of the ejection direction, whereby the shot sphere ejected in the horizontal direction from the shot sphere ejection nozzle is uniformly dispersed throughout the heat transfer tube group. A shot cleaning device. A shot in which dust adhered to the horizontal heat transfer tube group of the boiler that recovers heat from the exhaust gas is scattered from the upper part of the heat transfer tube group, and the dust adhering to the heat transfer tube group is removed by the falling collision of the shot ball. In the cleaning method,
A collision plate that collides with a shot sphere ejected in a horizontal direction from a shot sphere ejection nozzle installed above the heat transfer tube group, and above the shot sphere ejection nozzle so as to be orthogonal to the ejection direction of the shot sphere. provided, the angle between the vertical impingement plate provided in the tiltable said collision plate shaft impact plate axis that is horizontally disposed as an axis,
When the collision plate is upright with the angle θ decreased, the collided shot ball is dropped to the side close to the shot ball ejection nozzle, and when the θ is increased and the collision plate is laid down, The shot sphere is changed so that the shot sphere is dropped to the far side of the shot sphere ejection nozzle, and the distribution in the ejection direction is controlled, whereby the shot sphere ejected in the horizontal direction from the shot sphere ejection nozzle is changed to the entire heat transfer tube group. A shot cleaning method characterized by uniformly dispersing in the above.

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