JP4076318B2 - Insertion structure of steam soot blower - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a soot blower, and more particularly, to a steam soot blower used in a heat exchanger or the like using boiler exhaust gas.
[0002]
[Prior art]
In a heat exchanger using boiler exhaust gas, a steam soot blower is often used to remove soot adhering to heat transfer tubes and the like. Thus, condensate of steam, that is, a drain is generated with respect to the blowing of steam, and this drain may promote corrosion of components of the heat exchanger. Therefore, various countermeasures are taken. An example of this will be described with reference to “suit blower mounting seat” described in Japanese Utility Model Publication No. 62-10574.
Referring to FIG. 8, an insertion port 2 is provided in the outer wall 1 of the heat exchanger, and a soot blower is attached thereto. A cylindrical cap-shaped empty chamber 3 (hereinafter referred to as a pre-purge box) provided outside the outer wall 1 covering the insertion port 2 and a guide box 4 (hereinafter referred to as a seal box) connected coaxially thereto. ) Is fixed to the outer wall 1. The inner hole 3a of the pre-purge box 3 and the hole 4a of the seal box 4 are coaxial with the insertion port 2 of the outer wall 1 and have the same diameter. The hole 4a of the seal box 4 includes a detachable lid 5. A circular buffer plate 6 made of a perforated plate is arranged eccentrically in the pre-purge box 3, and a drain pipe 7 is attached to the lower part of the pre-purge box 3 to communicate with a drain tank (not shown).
[0003]
A soot blower steam outlet tube 9 is inserted with the lid 5 of the seal box 4 opened. In the standby position, the tip of the steam blowing tube 9 is located near the center of the pre-purge box 2. Since the high-temperature steam supply is stopped to the standby steam outlet tube 9, the temperature of the steam outlet tube 9 is lowered. When starting the fall of the heat exchanger, the steam main 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 pre-purge box 3 in the standby state, and the drain pipe 7 The soot blowing preparation operation, that is, the pre-purge operation is performed while draining the drain from the tank. And after raising the temperature of the steam blow-out pipe 9 and the superheat degree of the steam to a predetermined value by this pre-purge operation, the steam blow-out pipe 9 is inserted into the heat exchanger, and the internal soot is removed in earnest.
[0004]
In this way, in the steam soot blower, after performing the pre-purge operation in which high-temperature steam is caused to flow in the steam blowing pipe 9 including the feed pipe and the lance tube for a certain period of time, the temperature of the steam blowing pipe 9 and the degree of superheat of the steam are increased. The steam and the steam generated when the steam passes through the soot blower at the time of cleaning in the furnace by inserting the steam blow-out pipe 9 into the furnace and injecting the steam into the heat exchanger for full-scale cleaning. It is intended to prevent erosion and corrosion of the tube in the heat exchanger due to the drain brought in from the piping.
[0005]
[Problems to be solved by the invention]
However, in the structure of the above-described conventional apparatus, the pre-purge steam flows into the heat exchanger by stopping the tip of the steam blowing pipe 60 at the adjusted position in the pre-purge box 3 during the pre-purge operation. Is preventing. On the other hand, since the insertion port 2 is open regardless of whether the steam blow-out pipe 9 is on standby, pre-purge, or in-furnace cleaning, the pre-purge box 3 can be opened from the heat exchanger or the furnace containing the heat exchanger. Exhaust gas flows to the side.
[0006]
For this reason, when the heat exchanger to which the soot blower is attached is located close to the boiler exhaust gas source in front of the dust collector of the boiler facility, the exhaust gas in the furnace has a large amount of dust. Dust is brought into the pre-purge box 3 side through the port 2, and particularly during pre-purge operation, dust in the exhaust gas is solidified in contact with moisture and drain in the pre-purge, causing the drain pipe 7 to be clogged or blocked by this. May cause a backflow of the drain into the heat exchanger.
Accordingly, an object of the present invention is to provide a steam soot blower insertion portion structure capable of solving the problems caused by the dust entering the soot blower side and the coupling between the dust and the steam drain in the conventional structure described above. It is in.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides the following means.
As a first means, it has a pre-purge box provided in the outer wall of the heat exchanger so as to surround the insertion port of the outer wall, and a seal box connected to the pre-purge box, A ventilation block mechanism is provided that blocks ventilation between the heat exchanger side and the pre-purge box side and allows passage of the steam outlet pipe, and the ventilation block mechanism is mounted around the insertion port in the pre-purge box. It is composed of a nozzle mechanism that injects the air curtain into the heat exchanger chamber in a conical shape, and the ventilation block extends further from the tip of the steam blow pipe at the pre-purge position to the position passing through the insertion port. An insertion part structure for a steam soot blower is provided.
As a second means, in the first means, a steam soot blower characterized in that an air pressure adjusting means for maintaining the air pressure in the pre-purge box chamber higher than the internal gas pressure of the heat exchanger is provided. Provides an insertion part structure.
As a third means, an insertion port side seal box that covers the insertion port on the outer wall outer surface of the heat exchanger and is mounted on the side plate portion, a pre-purge box that is continuously mounted on the seal box, and a pre-purge box A steam soot blower comprising a high pressure air supply means that is configured to be connected to an outer seal box provided on the outside, and each seal box is adjusted and maintained at a pressure higher than the internal gas pressure of the heat exchanger. An insert structure is provided .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected over the whole figure including drawing regarding the above-mentioned prior art.
First, referring to FIG. 1, a soot blower insertion port 15 is provided on the outer wall 13 of the heat exchanger 11, and a pre-purge box 17 is provided on the outer surface of the outer wall 13 so as to cover the insertion port 15. A seal box 19 is attached to the surface of the pre-purge box 17 away from the outer wall 13, and the inner hole thereof is coaxial with the insertion port 15. Further, in the pre-purge box 17, a cylindrical buffer plate 21 made of a perforated plate provided eccentrically upward is provided, which is substantially coaxial with the central axis of the insertion port 15. A drain exhaust pipe 23 is connected to the bottom of the pre-purge 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 the soot blower is attached.
[0009]
Further, the structure of the portion that characterizes 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 communicates with an air supply pipe 29 extending outside the pre-purge box 17. Yes. The air supply pipe 29 communicates with a compressed air source (not shown), and nozzle holes are formed side by side in the inner peripheral portion of the nozzle pipe 27 so as to form an air curtain 31 that goes conically toward the inside of the heat exchanger. It has become. As shown in the drawing, the nozzle tube 27 is located inside the cylindrical buffer plate 21. A soot blower steam blow-out pipe 9 is coaxially inserted into the seal box 19. A known spring-type seal mechanism 33 is fitted and provided on the outer periphery of the steam blow-out pipe 9, and this is a ring shape that is pressed against the inner surfaces of the spring 33 a and both side insertion ports of the seal box 19. And a ring seal 33b also serving as a scraper . At the tip of the steam blowout pipe 9, the prolongation dummy pipe 8 used are spliced.
[0010]
Next, the operation of the embodiment having the above configuration will be described.
As shown in the figure, the soot blower steam blow-out pipe 9 is inserted through the inner hole of the seal box 19 and the insertion port 15 of the heat exchanger 11 to insert the tip into the heat exchanger 11, or the heat exchanger 11. It is attached so that the tip can be pulled out from the inside. In the standby state in which no dredging is performed, the tip end portion of the steam blow-out pipe 9 is positioned at the central portion in the pre-purge box 17.
Then, the compressed air supplied from the air supply pipe 29 to the annular nozzle pipe 27 is ejected from the nozzle holes, forming a conical air over curtain 31 facing the interior of the heat exchanger 11 inside the insertion opening 15 . Since the air curtain 31 formed in this way has a function of blocking the air flow, the exhaust gas containing dust flows into the pre-purge box 17 through the insertion port 15 in the standby state and the pre-purge operation. To prevent.
[0011]
In the case of dredging operation inside the heat exchanger 11, since the steam blowing hole of the steam blowing tube 9 enters deep inside the heat exchanger 11, the space between the outer peripheral surface of the steam blowing tube 9 and the annular nozzle tube 27 is In addition, a narrow annular space is defined. Therefore, since the amount of exhaust gas passing through here is small, air blowing may be omitted. Of course, if air is blown out, the air curtain 31 has a frustoconical shape, and an extremely efficient exhaust gas blocking effect can be obtained. Even when the amount of dust in the exhaust gas is large, since the extension dummy tube 8 is attached to the tip of the steam blowing tube 9, the same exhaust gas blocking effect as described above can be obtained even in the standby state and the pre-purge operation.
[0012]
Next, a partial modification example (modified embodiment) of the first embodiment will be described with reference to FIG. For example, if the pressure of the boiler exhaust gas as a heating medium of the heat exchanger is higher than normal, but if Takamere pressure of the feed air for the air over curtain accordingly predetermined air curtain is formed, air pressure is high Then, the risk that the pressure fluctuates and decreases by that amount increases. In such a case, as shown in FIG. 2, a pressurized air supply pipe 43 is connected to the pre-purge box 41, and the air pressure in the pre-purge box 41 is maintained equal to or higher than the exhaust gas pressure. If it does in this way, the air curtain 31 will be formed stably and the interruption | blocking effect of waste gas will be acquired similarly. The rest of the configuration of the modified embodiment of FIG. 2 is the same as that of FIG.
[0013]
Next, with reference to FIG. 3, an example of study examined by the present inventor according to the present invention will be described. Also in the description of the present study example, the description will focus on parts different from the embodiment of FIG.
In FIG. 3, a valve chamber 50 is formed between the outer wall 13 of the heat exchanger 11 and the pre-purge box 17. More specifically, the valve chamber 50 is defined by an outer shell 51 and a partition plate 53 that are integrally formed with the outer plate of the pre-purge box 17, and the steam blowing pipe 9 can pass through the partition plate 53. The insertion port 55 is 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 passes through the steam blowing pipe 9, but its inner diameter is such that a gap formed between the inner surface of the valve passage and the outer surface of the steam blowing pipe 9 becomes an allowable minimum value. Is set.
The other configurations of the pre-purge box 17 and the seal box 19 are the same as those in the embodiment of FIG.
[0014]
Next, the operation of the study example of FIG. 3 will be described. This description also focuses on the description of parts different from the case of the embodiment of FIG. In this example , the ball valve 59 is a functional alternative to the annular nozzle tube 27. When the steam blow-out pipe 9 is in the standby state and during the pre-purge operation, the ball valve 59 is closed, and the exhaust gas does not flow from the heat exchanger 11 to the pre-purge box 17 side. Therefore, no dust enters. At the time of cleaning the dredging furnace, the ball valve 59 is opened, the steam blow-out pipe 9 is projected into the heat exchanger 11 through the valve passage, and the steam is blown out to drop the dredging. As described above, 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 furnace gas into the pre-purge box 17 during furnace cleaning is suppressed to a very small amount. Is done.
[0015]
Although the ball valve 59 is used in the study example of FIG. 3, other types of valves such as a slide valve may be used. In this case, it becomes as shown in FIG. Since the operation of the valve is similar, only the different structure 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 port 67. A saddle type slide valve 70 is provided in the valve chamber 60. This saddle type slide valve 70 defines a valve passage coaxial with the insertion port 67 and a valve body 73 forming a valve seat 71, a valve body 75 which appears and disappears between the valve seats 71 and opens and closes the valve passage. A valve stem 77 is provided.
[0016]
Furthermore, in the study example of FIG. 3, instead of the ball valve 59, using a hinged opening and closing valve, it is modified deformed state as shown in FIGS. 5 and 6 is obtained. It will be described with reference to the modified deformation state in the drawing but will be described about a modified portion in the same manner as described above. A valve chamber 80 provided between the heat exchanger 11 and the pre-purge box 17 is defined by an outer shell 81 and a partition plate 83, and the partition plate 83 is formed with an insertion port 85 for the steam blowing pipe 9. ing. The diameter of the insertion port 85 is set so as to form a clearance having an allowable minimum interval with the steam blow-out pipe 9 of the soot blower. Further, an annular flange having a valve seat function to be described later is formed on the heat exchanger 11 side of the insertion port 85.
[0017]
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. The piston rod of the driving air cylinder 97 is connected to each of the arms 95 connected to the base of the valve plate 91, and the cylinder end of the air cylinder 97 is pivotally connected to the mounting support plate 87 of the valve chamber 80. Yes. Although not shown, the air cylinder 97 is connected to air supply / discharge piping. In the illustrated state, the air cylinder 97 is in a shortened state, and the valve plate 91 closes the insertion port 85. On the other hand, when air is supplied and the air cylinder 97 extends, the valve plate 91 rotates clockwise as indicated by the arrow, and when the two-dot chain line state is reached, the on-off valve 90 is fully opened. In the standby state of the soot blower and the pre-purge operation, the on-off valve 90 is closed and opened during the dredging operation.
On the contrary, the valve plate 91 may be configured to open and close the heat exchanger 11 side insertion port 15.
[0018]
Furthermore, a second embodiment of the present invention will be described with reference to FIG. Note that conceptually speaking, in this embodiment, seal boxes are respectively arranged on both sides of the pre-purge 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 includes a cylindrical outer shell 101, a side plate 103 that also serves as an attachment plate fixed in contact with the outer wall 13, and a side plate 105 to which the pre-purge box 110 is fixed. The insertion port has substantially the same size. A spring-type seal mechanism 33 similar to that described above is provided between the insertion openings of the side plates 103 and 105. As described above, the seal mechanism 33 includes 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 to communicate with the inside, and 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).
[0019]
Further, a pre-purge box 110 is connected to the outer shell 101 of the seal box 100. The pre-purge box 110 has an outer shell 111 and both side plates 113 and 115, and a drain pipe 23 is connected to the outer shell 111. An insertion port is provided at the center of both side plates 113 and 115, and a cylindrical buffer plate 21 made of a perforated plate is provided so as to surround it. The function of the pre-purge box 110 and the effect obtained thereby are the same as those in the above-described embodiment. Another seal box, that is, an outer seal box 120 is provided on the side plate 115 of the pre-purge box 110. The basic structure of the seal box 120 is the same as that of the seal box 100 regardless of the size, and includes an outer shell 121, side plates 123 and 125, and a high-pressure seal air supply pipe 127. Further, a spring type seal mechanism 33 is provided between the side plates 123 and 125. When the soot blower steam blowing pipe 9 is used, the extension dummy pipe 8 is attached to the tip thereof.
[0020]
In the case of this embodiment, the steam blow-out pipe 9 is in a standby state in the state shown in the figure. That is, in the standby state, the extension dummy tube 8 is located in the spring type seal mechanism 33 of the seal box 100, and the base side of the steam blowing tube 9 is located in the spring type seal mechanism 33 of the seal box 120. Further, heating by the pre-purge operation is performed in this standby state. Accordingly, in the standby state and the pre-purge operation, pressurized air is supplied from the high-pressure air supply pipes 107 and 127 into the seal boxes 100 and 120, and the air pressure is kept higher than the internal pressure of the heat exchanger 11. In this way, the exhaust gas is prevented from entering the pre-purge box 110 and dust does not enter. Further, even when cleaning the inside of the furnace, the dust blower 9 does not enter the pre-purge box 110 because the base side of the steam blowing pipe 9 is in the seal box 100.
[0021]
【The invention's effect】
As described above, according to the present invention, the insertion structure of the steam soot blower is connected to the pre-purge box provided on the outer wall of the heat exchanger so as to surround the insertion port of the outer wall, and the pre-purge box. A vent block mechanism is provided in the pre-purge box for blocking the ventilation between the heat exchanger side and the pre-purge box side and allowing the steam blowing pipe to pass therethrough. Comprises a nozzle mechanism that is mounted around the insertion port in the pre-purge box and injects the air curtain into a conical shape into the room of the heat exchanger, and the ventilation block is further provided at the tip of the steam outlet pipe at the pre-purge position. A steam blow pipe extension extending from the section to the position passing through the insertion port, or further, the air pressure in the pre-purge box chamber is controlled by the inside of the heat exchanger. An air pressure adjusting means for maintaining the pressure higher than the gas pressure is provided, or the insertion structure of the steam type soot blower is inserted in the outer plate of the outer wall of the heat exchanger, and is inserted in the side plate portion. Side seal box, a pre-purge box continuously attached to the seal box, and an outer seal box connected to the pre-purge box and provided on the outside. Each seal box has an internal gas of the heat exchanger. Since it is configured to include high-pressure air supply means that is adjusted and maintained above the pressure, it is possible to prevent inflow of exhaust gas from the heat exchanger side into the pre-purge box of the insertion portion structure, and dust in the exhaust gas Inflow, and generation of a reaction product between the steam drain from the soot blower and dust, or the occurrence of defects due to this, can be prevented.
[Brief description of the drawings]
FIG. 1 is a partial vertical sectional view showing a first embodiment of the present invention.
FIG. 2 is a partial vertical sectional view showing a modified embodiment obtained by modifying a part of the first embodiment of FIG. 1;
FIG. 3 is a partial elevational sectional view showing an example of examination studied by the present inventors in connection with the present invention .
4 is a partial elevational sectional view showing a modified reforming deformed state the study example portion of FIG.
5 is a partial elevational sectional view showing another modified variant condition obtained by modifying a part of study example of FIG.
6 is a partial elevational view showing a part of a modified variant state as viewed from line VI-VI direction of FIG.
FIG. 7 is a partial vertical sectional view showing a second embodiment of the present invention.
FIG. 8 is a partial vertical sectional view showing an example of a conventional structure.
[Explanation of symbols]
8 Extension dummy pipe 9 Steam blowout pipe 11 Heat exchanger 13 Outer wall 15 Insertion port 17 Prepurge box 19 Seal box 21 Cylindrical buffer plate 23 Drain pipe 27 Annular nozzle pipe 29 Air supply pipe 31 Air curtain 33 Spring type seal mechanism

Claims (3)

A pre-purge box provided on the outer wall of the heat exchanger so as to surround the insertion port of the outer wall; and a seal box connected to the pre-purge box; and in the pre-purge box, the heat exchanger side; A ventilation block mechanism that blocks ventilation from the pre-purge box side and allows passage of the steam outlet pipe is provided , and the ventilation block is mounted around the insertion port in the pre-purge box. A nozzle mechanism that injects the air curtain into a conical shape, and the air-flow blocking mechanism further includes an extension of the steam blow pipe that reaches the position passing through the insertion port from the tip of the steam blow pipe at the pre-purge position. Characteristic steam soot blower insertion part structure . Wherein the air pressure of the pre-purge box chamber, the insertion portion structure of a steam sootblower according to claim 1, characterized in that the air pressure adjusting means for maintaining higher than the internal gas pressure of the heat exchanger is provided.   An insertion port side seal box which covers the insertion port on the outer wall of the heat exchanger and is mounted on the side plate portion, a pre-purge box which is continuously mounted on the seal box, and an outer side connected to the pre-purge box. A steam soot blower insertion portion structure comprising a high-pressure air supply means that is configured to include an outer seal box, and each seal box is adjusted and maintained at a pressure higher than the internal gas pressure of the heat exchanger.

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