JP2002162018A - Insertion section structure of vaporization soot blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent undesirable reaction from happening between a waste gas duct and a vapor drain upon insertion of a vapor blow-off pipe for soot blower to a heat exchanger. SOLUTION: In an insertion section structure of a soot blower including a vapor blow-off pipe 9, there are provided a pre-purging box 17 on an outer wall 13 of a heat exchanger 11, surrounding an insertion hole 15, and a sealing box 19 connected with the pre-purging box 17. There are further provided in the pre-purging box 17 an annular nozzle pipe 27 and an air supply pipe 29 which form an air curtain 31 which interrupts ventilation between the side of the heat exchanger 11 and the side of the pre-purging box 17 and permits the vapor blow-off pipe 9 to pass therethrough.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soot blower, and more particularly to a steam type soot blower used for a heat exchanger using exhaust gas from a boiler.

[0002]

2. Description of the Related Art In a heat exchanger using exhaust gas from a boiler, a steam-type soot blower is often used to remove soot and the like attached to a heat transfer tube or the like. Thus, with respect to the steam blowing, steam condensate or drain is generated,
Since the drain may promote corrosion of the components of the heat exchanger, various measures have been taken. An example of this will be described with reference to a "suit blower mounting seat" described in Japanese Utility Model Publication No. Sho 62-10574. Referring to FIG. 8, an insertion port 2 is provided on an outer wall 1 of the heat exchanger, and a soot blower is attached thereto. A cylindrical cap-shaped vacant space 3 (hereinafter, referred to as a cover 3) provided outside the outer wall 1 covering the insertion opening 2.
It is called a prepurge box. ) And a guide box 4 (hereinafter referred to as a seal box) coaxially connected thereto are fixed to the outer wall 1. The inner hole 3a of the prepurge box 3 and the hole 4a of the seal box 4
And is the same in diameter as the insertion port 2. The hole 4 a of the seal box 4 has a removable lid 5. A circular buffer plate 6 made of a perforated plate is eccentrically arranged in the prepurge box 3, and a drain tube 7 is attached to a lower portion of the prepurge box 3 to communicate with a drain tank (not shown).

[0003] A steam blow-out pipe 9 of a soot blower is inserted with the lid 5 of the seal box 4 opened. Then, in the standby position, the steam blowing pipe 9
Is located near the center of the prepurge box 2. Since the supply of the high-temperature steam to the steam blow-out pipe 9 in the standby state is stopped, the temperature of the steam blow-out pipe 9 is lowered.
Then, when starting to remove the soot from the heat exchanger, the steam source plug of the soot blower is opened to supply high-temperature steam to the steam blow-out pipe 9, and the steam is discharged into the prepurge box 3 in a standby state, and the drain pipe 7 is discharged. A soot blowing preparation operation, that is, a prepurge operation, is performed while the drain is being released from the air conditioner. And
After the temperature of the steam blow-out pipe 9 and the degree of superheat of the steam are raised to predetermined values by this pre-purge operation, the steam blow-out pipe 9 is inserted into the heat exchanger to perform full-scale internal soot dropping.

[0004] In this manner, in the steam type soot blower, the pre-purge operation of flowing high-temperature steam into the steam blow-out pipe 9 including the feed pipe and the lance tube for a certain period of time is performed to increase the temperature of the steam blow-out pipe 9 and the degree of superheat of the steam. After that, the steam blow-out pipe 9 is inserted into the furnace, and full-scale soot cleaning is performed by injecting the steam into the heat exchanger, so that the steam is generated when the steam passes through the soot blower at the time of cleaning the inside of the furnace. It is intended to prevent erosion and corrosion of the tube in the heat exchanger due to the drain brought in from the drain and the steam pipe.

[0005]

However, in the structure of the above-mentioned conventional apparatus, the steam blow-out pipe 6 is not used during the pre-purge operation.
By stopping the front end of the zero at the adjusted position in the prepurge box 3, the steam during the prepurge is prevented from flowing into the heat exchanger. On the other hand, regardless of whether the steam blow-out pipe 9 is on standby, during prepurge, or during furnace cleaning, the insertion port 2 is open. Exhaust gas flows into the side.

For this reason, when the heat exchanger to which the soot blower is attached is located at a position near the boiler exhaust gas source before the dust collector of the boiler equipment, the amount of dust contained in the exhaust gas in the furnace is large. The exhaust gas carries dust into the prepurge box 3 through the insertion port 2, and particularly during the prepurge operation, the dust in the exhaust gas contacts the moisture and the drain during the prepurge and solidifies, and the drain pipe 7
Clogging or blockage due to this may cause drain backflow into the heat exchanger. Therefore, an object of the present invention is to provide a steam soot blower insertion structure which can solve the problems caused by the entry of dust due to exhaust gas into the soot blower side and the combination of the dust and the steam drain in the conventional structure described above. It is in.

[0007]

According to the present invention, there is provided a steam type soot blower having an insertion portion structure provided on an outer wall of a heat exchanger so as to surround an insertion opening of the outer wall. It has a purge box and a seal box connected to the prepurge box. In the prepurge box, the heat exchanger side and the prepurge box side are ventilated, and the passage of the steam blow-out pipe is allowed. A ventilation blocking mechanism is provided. As the ventilation shut-off mechanism, a hydrodynamic means such as an air curtain and a mechanical opening / closing valve such as a ball valve, a slide valve, and a hinge valve are suitable. Furthermore, when using a hydrodynamic means such as an air curtain, an extension dummy pipe only simulating the outer shape is attached to the end of the steam blow-out pipe of the soot blower to reinforce the hydrodynamic ventilation shutoff function, or to insert the insertion port. It is also preferable to provide a means for generating a pressure gradient therebetween.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The same parts are denoted by the same reference numerals throughout the drawings, including the drawings related to the above-described conventional technology. First, referring to FIG.
3 is provided with a soot blower insertion port 15, which covers the insertion port 15 and is provided on the outer surface of the outer wall 13.
Is provided. A seal box 19 is attached to a surface of the prepurge box 17 remote from the outer wall 13, and an inner hole thereof is coaxial with the insertion port 15. Furthermore,
A cylindrical buffer plate 21 made of a perforated plate provided eccentrically upward is provided in the prepurge box 17.
This is substantially coaxial with the center axis of the insertion port 15. A drain drain tube 23 is connected to the bottom of the prepurge box 17 extending downward relative to the cylindrical buffer plate 21, and communicates with a drain tank (not shown). A detachable lid 25 is provided at the outer end of the seal box 19, and is removed when a soot blower is attached.

Further, the structure of a portion which is a feature of the present invention will be described. An annular nozzle pipe 27 is provided on the outer wall 13 around the insertion port 15, and this is connected to an air supply pipe 29 extending outside the prepurge box 17. I'm in contact. The air supply pipe 29 communicates with a compressed air source (not shown).
Nozzle holes are formed side by side in the inner peripheral portion of the heat exchanger to form a conical air curtain 31 toward the inside of the heat exchanger. As shown, the nozzle tube 27 is located inside the cylindrical buffer plate 21. The steam blower pipe 9 of the soot blower is coaxially inserted into the seal box 19. A well-known spring-type sealing mechanism 33 is fitted and provided on the outer periphery of the steam blow-out pipe 9. The spring-type sealing mechanism 33 is a ring-shaped seal which is pressed against the inner surfaces of both side insertion ports of the seal box 19 by the spring 33 a. And a ring seal 33b also serving as a scraper. The extension dummy pipe 8 is spliced to the tip of the steam blow-out pipe 9 if necessary.

Next, the operation of the embodiment having the above configuration will be described. As shown, the steam blow-out pipe 9 of the soot blower has an inner hole of the seal box 19 and an insertion port 1 of the heat exchanger 11.
5, the tip is inserted into the inside of the heat exchanger 11 or attached so that the tip can be pulled out from the inside of the heat exchanger 11. Then, in a standby state in which soot removal is not performed, the distal end of the steam blow-out pipe 9 is positioned at the center of the prepurge box 17. Then, the compressed air supplied from the air supply pipe 29 to the annular nozzle pipe 27 is jetted from the nozzle hole to form a conical air curtain 31 facing the inside of the heat exchanger 11 inside the insertion port 15. The air curtain 31 thus formed
Since it has a function of shutting off the flow of air, exhaust gas containing dust is prevented from flowing into the prepurge box 17 through the insertion port 15 in the standby state and during the prepurge operation.

In the case of the soot removal operation inside the heat exchanger 11, the steam blowout hole of the steam blowout pipe 9 is connected to the heat exchanger 11.
, A narrow annular space is defined between the outer peripheral surface of the steam blowing pipe 9 and the annular nozzle pipe 27. Therefore, the amount of exhaust gas passing here is small,
The blowing of air may be omitted. Of course, if air is blown out, the air curtain 31 becomes a truncated conical surface, and an extremely efficient exhaust gas blocking effect can be obtained. When the amount of dust in the exhaust gas is large, the same exhaust gas shut-off effect as described above can be obtained in the standby state and during the prepurge operation by attaching the extension dummy pipe 8 to the end of the steam blowing pipe 9.

Next, a partially modified example of the above embodiment will be described with reference to FIG. For example, when the pressure of the boiler exhaust gas, which is the heating medium of the heat exchanger, is higher than usual, a predetermined air curtain is formed if the pressure of the air curtain supply air is increased accordingly, but when the air pressure increases. ,
The risk that the pressure fluctuates and drops is increased accordingly.
In such a case, a pressurized air supply pipe 43 is connected to the prepurge box 41 as shown in FIG. 2 to maintain the air pressure in the prepurge box 41 equal to or higher than the exhaust gas pressure. By doing so, the air curtain 31 is formed stably, and the effect of shutting off exhaust gas is similarly obtained. The other configurations of the embodiment of FIG. 2 are the same as those of FIG. 1 as indicated by the reference numerals, and description thereof is omitted.

Next, another embodiment of the present invention will be described with reference to FIG. Also in the description of the present embodiment, a description will be given focusing on portions different from the embodiment of FIG. In FIG. 3, the outer wall 13 of the heat exchanger 11 and the prepurge box 17
And the valve chamber 50 is formed. More specifically, the valve chamber 50 is defined by an outer shell 51 and a partition plate 53 integrally formed with the outer plate of the pre-purge box 17, and the partition plate 53 has a degree to which the steam blow-out pipe 9 can pass. Insertion slot 5
5 are drilled. A ball valve 59 is provided in the valve chamber 50, and the valve passage is coaxial with the insertion port 15 of the outer wall 13. The valve passage of the ball valve 59 allows the steam blow-out pipe 9 to pass therethrough, and has an inner diameter such that a gap formed between the inner surface of the valve passage and the outer face of the steam blow-out pipe 9 becomes an allowable minimum value. Is set. The other configurations of the prepurge box 17 and the seal box 19 are the same as those in the embodiment of FIG.

Next, the operation of the embodiment shown in FIG. 3 will be described.
This description also focuses on the description of the portions different from those in the embodiment of FIG. In this embodiment, the ball valve 59
Is a functional replacement for the annular nozzle tube 27. When the steam blow-out pipe 9 is in the standby state and during the prepurge operation, the ball valve 59 is closed, and no exhaust gas flows from the heat exchanger 11 to the prepurge box 17 side. Therefore, there is no entry of dust. When cleaning the inside of the furnace for soot removal, the ball valve 59 is opened, the steam blow-out pipe 9 is protruded into the heat exchanger 11 through the valve passage, and steam is blown out to perform soot removal. As previously mentioned,
Since the gap between the outer peripheral surface of the steam blow-out pipe 9 and the inner surface of the valve passage of the ball valve 59 is small, the flow of the furnace gas into the prepurge box 17 during furnace cleaning is suppressed to a very small amount.

Although the ball valve 59 is used in the embodiment shown in FIG. 3, another type of valve, for example, a slide valve may be used. In this case, the result is as shown in FIG. Since the operation of the valves is similar, only the different structures will be described. In the figure,
The valve chamber 60 is defined by an outer shell 61, a partition plate 63, and a side plate 65, and the partition plate 63 and the side plate 65 have an insertion opening 67. A vertical slide valve 70 is provided in the valve chamber 60. The vertical slide valve 70 defines a valve passage coaxial with the insertion port 67 and a valve box 7 forming a valve seat 71.
3. A valve body 75 and a valve stem 77 which protrude and retract between the valve seats 71 to open and close the valve passage.

Further, when a hinge type on-off valve is used in place of the ball valve 59 in the embodiment of FIG. 3, a modified embodiment as shown in FIGS. 5 and 6 is obtained. This modified embodiment will be described with reference to the drawings, but the description will focus on the modified parts as in the above description. A valve chamber 80 provided between the heat exchanger 11 and the prepurge box 17 is defined by an outer shell 81 and a partition plate 83, and an insertion port 85 for the steam blow-out pipe 9 is formed in the partition plate 83. ing. The diameter of the insertion port 85 is set so as to form a clearance with an allowable minimum interval between the insertion port 85 and the steam blowing pipe 9 of the soot blower. Further, on the heat exchanger 11 side of the insertion port 85, an annular flange having a function of a valve seat of a valve described later is formed.

On the other hand, a hinge type on-off valve 90 is provided in the valve chamber 80. The valve plate 91 of the on-off valve 90 is pivotally provided via a horizontal shaft 93 supported by the partition plate 83. A piston rod of a driving air cylinder 97 is connected to an arm 95 connected to a base of the valve plate 91, and a cylinder end of the air cylinder 97 is connected to a valve chamber 80.
Are pivotally connected to the mounting support plate 97 of the first embodiment. Although not shown, an air supply / discharge pipe is connected to the air cylinder 97. In the illustrated state, the air cylinder 97 is in a shortened state, and the valve plate 91 has the insertion port 85 closed. On the other hand, when the air is supplied and the air cylinder 97 is extended, the valve plate 91 rotates clockwise as shown by the arrow, and when the state becomes a two-dot chain line state, the on-off valve 90 is completely opened. In the standby state of the soot blower and during the pre-purge operation,
The on-off valve 90 is closed and opened during the soot removal operation.
Note that the valve plate 91 may be provided so as to open and close the insertion port 15 on the heat exchanger 11 side.

Further, another embodiment of the present invention will be described with reference to FIG. Note that, conceptually, in this embodiment, seal boxes are arranged on both sides of the prepurge box. Referring to FIG. 7, a seal box 100 is provided on the outer surface of the outer wall 13 of the heat exchanger 11 so as to surround the insertion port 15. The seal box 100 has a cylindrical outer shell 101, a side plate 103 also serving as an attachment plate fixed to and in contact with the outer wall 13, and a side plate 105 to which a prepurge box 110 is fixed. It has an insertion port of substantially the same size. A spring-type sealing mechanism 33 similar to that described above is provided between the insertion openings of the side plates 103 and 105. The sealing mechanism 33
As described above, it is composed of the metal ring seal 33a and the spring 33b. Further, a high-pressure seal air supply pipe 107 is connected to the outer shell 101 and communicates with the inside, so that the inside of the seal box 100 is maintained at a high pressure (air pressure higher than the gas pressure on the heat exchanger 11 side).

Further, the outer shell 101 of the seal box 100
Is provided with a prepurge box 110 connected thereto. The prepurge box 110 has an outer shell 111 and both side plates 113 and 115, and the drain shell 23 is connected to the outer shell 111. An insertion opening is provided at the center of both side plates 113 and 115, and a perforated cylindrical buffer plate 21 is provided so as to surround the insertion opening. The function of the prepurge box 110 and the effects obtained thereby are the same as those in the above-described embodiment. On the side plate 115 of the prepurge box 110, another seal box, that is, an outer seal box 120 is provided. Regardless of the size of the seal box 120, its basic structure is the same as that of the seal box 100.
3, 125 and a high pressure seal air supply pipe 127. Further, a spring-type sealing mechanism 33 is provided between the side plates 123 and 125. When the steam blow-out pipe 9 of the soot blower is used, the extension dummy pipe 8 is attached to the tip thereof.

In the case of this embodiment, the steam blowing pipe 9 is in a standby state in the state shown in the figure. That is, in the standby state, the extension dummy pipe 8 is located inside the spring-type sealing mechanism 33 of the seal box 100, and the base side of the steam blowing pipe 9 is
Located within. Further, in this standby state, heating by the pre-purge operation is performed. Therefore, in the standby state and during the pre-purge operation, the high-pressure air supply pipes 107 and 12
Pressurized air is supplied into each of the seal boxes 100 and 120 from 7, and is maintained at an air pressure higher than the internal pressure of the heat exchanger 11. In this way, the exhaust gas is prevented from entering the prepurge box 110, and no dust enters.
Further, even when cleaning the inside of the furnace for removing soot, since the base side of the steam blow-out pipe 9 is both inside the seal box 100, the dust in the exhaust gas is similarly removed from the prepurge box 11
It does not enter 0.

[0021]

As described above, according to the present invention,
At the insertion port for inserting the soot blower into the heat exchanger, a ventilation shutoff mechanism including a hydrodynamic means such as an air curtain or a mechanical opening / closing valve such as a ball valve is provided. Since the flow of exhaust gas into the prepurge box is prevented, the flow of dust in the exhaust gas is prevented, and the generation of a reaction product between the steam drain and the dust from the soot blower and the occurrence of problems due to this are prevented. it can.

[Brief description of the drawings]

FIG. 1 is a partial vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a partial vertical sectional view showing a modified embodiment in which a part of the embodiment of FIG. 1 is modified.

FIG. 3 is a partial vertical sectional view showing another embodiment of the present invention.

FIG. 4 is a partial sectional elevation view showing a modified embodiment in which a part of the embodiment of FIG. 3 is modified.

FIG. 5 is a partial sectional elevation view showing another modified embodiment in which a part of the embodiment of FIG. 3 is modified.

FIG. 6 is a partial elevational view showing a part of the modified embodiment as seen from the direction of the line VI-VI of FIG. 5;

FIG. 7 is a partial vertical sectional view showing still another embodiment of the present invention.

FIG. 8 is a partial vertical sectional view showing an example of a conventional structure.

[Explanation of symbols]

 Reference Signs List 8 extension dummy pipe 9 steam blow-out pipe 11 heat exchanger 13 outer wall 15 insertion port 17 prepurge box 19 seal box 21 cylindrical buffer plate 23 drain drain pipe 27 annular nozzle pipe 29 air supply pipe 31 air curtain 33 spring-type sealing mechanism

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Murai F-term in Hiroshima Works, Mitsubishi Heavy Industries, Ltd. F-term (reference) 3K061 QC02 QC35 QC39

Claims (9)

[Claims] 1. A prepurge box provided on an outer wall of a heat exchanger so as to surround an insertion opening of the outer wall, and a seal box connected to the prepurge box. An insertion part structure for a steam-type soot blower, characterized by being provided with a ventilation cut-off mechanism for blocking ventilation between a heat exchanger side and a prepurge box side and allowing passage of a steam blowing pipe. 2. The method according to claim 1, wherein the ventilation shut-off mechanism comprises a nozzle mechanism mounted around the insertion opening in the prepurge box and configured to jet a conical air curtain into the room of the heat exchanger. An insertion part structure for the steam type soot blower according to claim 1. 3. The steam according to claim 2, wherein the ventilation shut-off mechanism further comprises an extension of the steam blow-off pipe reaching from a distal end of the steam blow-off pipe at a prepurge position to a position passing through the insertion port. Insertion structure of a soot blower. 4. An air pressure adjusting means for maintaining an air pressure in the pre-purge box chamber higher than an internal gas pressure of the heat exchanger is provided. Insert structure of the steam-type soot blower described in 1. 5. An insertion part structure for inserting a steam blow-out pipe of a steam-type soot blower into a heat exchanger,
A valve chamber provided outside the insertion opening of the outer wall of the heat exchanger, a prepurge box provided outside the valve chamber, and a seal box provided outside the prepurge box,
An on-off valve provided between both insertion ports of the valve chamber, and a standby and prepurge heating of the steam blow-off pipe is performed in a closed state of the on-off valve, and a soot blowing cleaning in the heat exchanger is performed in an open state. A steam type soot blower insertion structure, characterized in that it is configured as described above. 6. The structure of claim 5, wherein the on-off valve is a ball valve. 7. The steam type soot blower insertion part structure according to claim 5, wherein the on-off valve is a vertical slide valve. 8. The valve according to claim 5, wherein the opening / closing valve is configured to open / close one of the outer wall insertion port and the valve chamber side insertion port by hinge-type rotation of a valve plate by driving means. Insert structure of the steam-type soot blower described in 1. 9. An insertion-port-side seal box, which is mounted on a side plate portion of an outer surface of an outer wall of the heat exchanger so as to cover the insertion port, a prepurge box continuously mounted on the seal box,
An outer seal box connected to the prepurge box and provided outside, and each seal box is provided with high-pressure air supply means adjusted and maintained at a gas pressure higher than the internal gas pressure of the heat exchanger. Of a steam-type soot blower.