JP6603759B1 - Method and apparatus for preventing low temperature corrosion near the initial introduction part of a piping group in an air heating device - Google Patents

Abstract

An air heating apparatus in which an air flow changing unit is disposed in a portion where condensation is likely to occur in an air heating chamber, and dust and condensation on the surface of a heat exchange tube are removed and low temperature corrosion is prevented by the air flow changed by the air flow changing member. A dust removing device is provided. An air heating chamber into which combustion gas is introduced, a heat exchange pipe disposed in the air heating chamber and piped at predetermined column intervals and predetermined row intervals, and attached to the heat exchange tube A dust removing device for an air heating device provided with a dust removing device for removing dust that has been disposed, and a metal chain 40 for changing the flow of combustion gas is disposed in the air heating chamber, and the heat exchange pipe 2 by the air flow changed by the metal chain 40. It is configured to remove dust adhering to the surface, and includes means for moving the suspended metal chain 40 up and down. [Selection] Figure 9

Description

The present invention relates to a method and an apparatus for preventing low temperature corrosion in the vicinity of an initial introduction portion of a piping group in an air heating device , and in particular, an air flow changing body is disposed in a portion where condensation is likely to occur in an air heating chamber and is changed by an air flow changing member. The present invention relates to a method and an apparatus for preventing low-temperature corrosion in the vicinity of an initial introduction portion of a piping group in an air heating apparatus that removes dust and condensation on the surface of a heat exchange pipe and prevents low-temperature corrosion by an air flow .

This type of air heating apparatus is provided with a pipe group in which a large number of heat exchange pipes are piped at constant column intervals and constant row intervals in an air heating chamber through which combustion gas passes, and each heat constituting the pipe group is provided. The air circulated in the exchange pipe is heated by the heat of the combustion gas.
In such an air heating device, there is a problem that dust contained in the combustion gas adheres to the heat exchange pipes constituting the pipe group, thereby reducing the heat exchange efficiency.
Conventionally, as a dust removing device for removing dust adhering to a heat exchange pipe, for example, a vertical member (string-like body) is provided so as to pass in the vertical direction within a column interval of a pipe group, and this vertical member is subjected to heat exchange. It is known that the dust adhered to the side surface of the heat exchange tube is scraped and removed by reciprocating in the tube extension direction (see Patent Document 1).

In addition, in a waste incineration plant that recovers the heat of high-temperature exhaust gas discharged from an incinerator that incinerates waste such as municipal waste, the water vapor and sulfur components contained in the exhaust gas fall below the dew point temperature. There is a problem in that it condenses on the metal surface and causes low temperature corrosion by sulfuric acid aqueous solution.
In order to prevent this low-temperature corrosion, control operation is performed so that the iron skin temperature of the heat exchange pipe of the heat exchanger is equal to or higher than the dew point temperature (see Patent Document 2).

JP 2001-241886 A JP 2011-237137 A

However, as in Patent Document 1, in the case where a vertical member is provided so as to pass through the vertical interval of the piping group in the vertical direction, the vertical member reciprocates in the extension direction of the heat exchange tube, thereby the side surface of the heat exchange tube. Although the dust adhering to the side can be removed, the dust adhering to the upper surface side and the lower surface side of the heat exchange tube cannot be removed.
In addition, as in the technique of Patent Document 2, there is a problem that a temperature difference is present in the air heating device only by performing a controlled operation, so that a portion having a dew point temperature or less is generated, and low temperature corrosion cannot be sufficiently prevented. It was.
The present invention has been made in order to solve such a conventional problem, and an object of the present invention is to arrange an air flow changing portion in a portion where condensation is likely to occur in the air heating chamber and to change the air flow changed by the air flow changing member. Accordingly, it is an object of the present invention to provide a dust removal device in an air heating device that removes dust and condensation on the surface of a heat exchange tube and prevents low-temperature corrosion.

As a means for achieving the above object, according to the first aspect of the present invention, an air heating chamber into which combustion gas is introduced and the air heating chamber are arranged in the air heating chamber and piped at a predetermined column interval and a predetermined row interval. In an air heater equipped with a heat exchange tube, the metal chain is suspended only along the vicinity of the initial introduction part of the piping group that introduces air in the air heating chamber, and the metal chain is reflected vertically while moving the suspended metal chain up and down. Thus, a method of removing dust near the initial introduction portion of the piping group, removing condensation, and preventing low temperature corrosion using the airflow that changes in this way .

According to a second aspect of the present invention, there is provided an apparatus used in the method of the first aspect, wherein a metal chain suspended along the vicinity of an initial introduction portion of a piping group for introducing air in an air heating chamber, and the metal chain A means for moving up and down is provided .

In the present invention, since the metal chain is disposed in the vicinity of the heat exchange pipe in the air heating chamber, the combustion gas is reflected in the complicated shape of the metal chain, and airflow is blown to the heat exchange pipe from multiple directions.

In the present invention, since the metal chain is suspended along the vicinity of the initial introduction portion of the pipe group for introducing air, it is possible to effectively remove dust at a site where low temperature corrosion is likely to occur.

In the present invention, since the means for moving the hanging metal chain up and down is provided, the combustion gas is blown from multiple directions while the wind pressure changes as the position of the metal chain changes, and the entire periphery of the metal chain is effectively removed. .

It is a side view which shows a heat exchange pipe, a link frame, and a dust removal apparatus. It is a front view which shows a heat exchange pipe, a link frame, and a dust removal apparatus. It is a top view of the dust removal apparatus in an air heating apparatus. It is a perspective view which shows the arrangement | positioning state of a heat exchange pipe and a rod. It is an enlarged front view of the upper arm part of a dust remover. It is an enlarged front view of the lower arm part of a dust remover. It is an enlarged side view of the upper arm part of a dust remover. It is an enlarged side view of the lower arm part of a dust remover. It is explanatory drawing which shows the operating state of a chain up-and-down arm. It is explanatory drawing which shows the attachment state of a metal chain. It is explanatory drawing of the incineration facility provided with the air heating apparatus.

As shown in FIG. 11, the air heating apparatus 1 of the present embodiment is incorporated in an exhaust gas cooling / exhaust gas treatment system 81 provided in a stoker furnace 80 as a waste incineration facility.
The stoker furnace 80 puts the garbage stored in the garbage pit 82 into the garbage hopper 83, supplies air from the lower part of the combustion apparatus, and dries / heats it on the grate (stoker), stirs / moves it, and burns it. It is like that.

  Combustion exhaust gas generated by combustion in the stoker furnace 80 is provided with a recombustion chamber 84, a combustion gas cooling chamber 85, an air heating chamber 86, a temperature reducing tower 87, and a dust collector 88, and these combustion gases are sequentially supplied. After passing through the induction blower 89, the exhaust gas is finally discharged from the chimney 90 to the outside air.

As shown in FIGS. 1 to 10, the air heating apparatus 1 includes a group of pipes 11, 12, 13, 14, 15, 16 in which a large number of heat exchange pipes 2 are piped at constant column intervals and constant row intervals. Is provided in the air heating chamber 86.
In this embodiment, the first piping group 11, the second piping group 12, the third piping group 13, the fourth piping group 14, the fifth piping group 15, and the sixth piping group 16 are vertically moved in the air heating chamber 86. There are six stages in the direction.
The first pipe group 11 to the sixth pipe group 16 are adjacent to each other in the vertical direction, and the column interval and the row interval are formed to be the same, and each heat exchange pipe constituting the first pipe group 11 to the sixth pipe group 16. The tube diameter and tube length of 2 are the same.

  Further, as shown in FIG. 1, an air introduction duct 20 is provided so as to cover one end (right end) of each heat exchange pipe 2 constituting the first pipe group 11, and each of the first pipe group 11 is constituted. A second communication duct 21 is provided to cover the other end (left end) of the heat exchange pipe 2 and the other end (left end) of each heat exchange pipe 2 constituting the second pipe group 12, and the second pipe. The second communication duct 22 covers the one end (right end) of each heat exchange pipe 2 constituting the group 12 and the one end (right end) of each heat exchange pipe 2 constituting the third pipe group 13. It is provided and covers the other end (left end) of each heat exchange pipe 2 constituting the third pipe group 13 and the other end (left end) of each heat exchange pipe 2 constituting the fourth pipe group 14. A third communication duct 23 is provided, and one end port (right end port) and fifth pipe of each heat exchange pipe 2 constituting the fourth pipe group 14. The fourth communication duct 24 is provided so as to cover one end port (right end port) of each heat exchange pipe 2 that constitutes 15, and the other end port (left end port) of each heat exchange pipe 2 that constitutes the fifth pipe group 15. ) And the fifth communication duct 25 is provided so as to cover the other end (left end) of each heat exchange pipe 2 constituting the sixth pipe group 16, and each heat exchange pipe 2 constituting the sixth pipe group 16. A discharge duct 26 is provided so as to cover the other end (right end).

  Then, air is supplied from the blower to the air introduction duct 20, and the air is supplied to the first pipe group 11 → the first communication duct 21 → the second pipe group 12 → the second communication duct 22 → the third pipe group 13 → The third communication duct 23, the fourth piping group 14, the fourth communication duct 24, the fifth piping group 15, the fifth communication duct 25, the sixth piping group 16, and the discharge duct 26 are circulated in this order.

In the air heating chamber 86, the combustion gas burned in the recombustion chamber 84 is introduced so as to flow from the lower side to the upper side through the combustion gas cooling chamber 85. The air flowing through the air heating device 1 is heated by heat exchange with the heat of the air, and the heated air is used as the combustion air of the stoker furnace 80.
The combustion gas that has passed through the air heating chamber 86 is subjected to heat exchange with the air supplied to the air heating device 1, and then the temperature of the exhaust gas is lowered by water spraying by the temperature reducing tower 87. Can supply the combustion gas in a state where the temperature is lowered.

The air heating device 1 is provided with a dust removing device for removing dust adhering to the heat exchange pipes constituting each pipe group.
This dust removing apparatus includes a slide body that reciprocates on a heat exchange pipe, slide drive means that reciprocates the slide body, and a metal chain 40 that is disposed along the vicinity of an initial introduction portion of a pipe group that introduces air. A chain mounting rod 41 for suspending the metal chain 40 and a chain vertical arm 42 for moving the chain mounting rod 41 up and down are provided.

The slide body is composed of a metal round bar 30.
The rod 30 is stretched in a direction orthogonal to the heat exchange pipe 2. And it arrange | positions on each step | level of the heat exchange pipe 2 parallel in the horizontal direction.
Four rods are inserted into each horizontal stage at a predetermined interval (see FIG. 3).
The rod is placed on the heat exchange tube by its own weight, and is therefore in contact with the upper side of the heat exchange tube.

The slide drive means includes an electric cylinder 31, a piston 32 that reciprocates a predetermined stroke by the electric cylinder, a rotation shaft 33 that rotates by the reciprocation of the piston 32, and an arm that protrudes from the rotation shaft 33. 34 and a link frame 35 connected to the arm 34.
The piston 32 can be a drive mechanism using an air cylinder or a hydraulic cylinder.
The electric cylinder 31, the piston 32, the rotation shaft 33, and the arm 34 are respectively disposed at the upper and lower portions of the air heating device 1.

  The rotating shaft 33 extends across the pipe group in the direction perpendicular to the upper and lower sides of the pipe group in the air heating device. In the present embodiment, four rotating shafts 33 are arranged on the upper side and the lower side, respectively.

From the rotation shaft 33, arms 34 are projected in three places toward the pipe group. That is, the arm 34 protrudes from a part located at both left and right ends of the pipe group and a part located at the center of the pipe group.
The tip of the arm 34 protruding from the rotating shaft is connected to the link frame 35, and receives the reciprocating motion of the piston 32 to transmit the rotational power to the link frame 35.
A chain vertical arm 42, which will be described later, protrudes from the rotation shaft on the air inlet side among the four upper rotation shafts.

The link frames 35 are arranged vertically in the vertical direction of the pipe group, and are arranged at three places on the left and right side surfaces and the center of the pipe group. That is, a series of link frames 35 provided at three positions on the left and right side surfaces and the center of the pipe group are respectively provided on the four rotating shafts 33 to constitute a slide mechanism for the four-link frame 35.
The upper and lower ends of the link frame 35 are connected to an arm 34, and slide in the horizontal direction while moving up and down as the arm 34 rotates.
The upper end of the link frame 35 is pivotally supported by the arm 34, while the lower end is connected to the arm 34 through the long hole 36 (see FIG. 8). For this reason, the arm 34 slides through the long hole 36 to allow the link frame 35 to move up and down.

A long hole 37 is formed in the center of the link frame 35 in the length direction. The long hole 37 is formed by joining L-shaped long steel materials to form a long gap at the center (see FIG. 4).
The rod 30 is connected through the long hole 37, and both ends of the rod 30 are fastened with nuts 38 so as not to come out. The rod 30 is sandwiched between the long holes 37 so as to be movable up and down.
For this reason, the rod 30 is allowed to move in the vertical direction, and the weight of the rod 30 is applied to the heat exchange pipe 2 so that the rod 30 is in contact with the heat exchange pipe 2.
In addition, as a formation method of the long hole 37, it is also possible to cut long steel material and to form a long hole.

In this embodiment, the metal chain 40 is employed as the airflow changing member.
The metal chain 40 is a long object formed by connecting elliptical metal rings in series, and is vertically arranged passing through the vertical interval of the first piping group (see FIGS. 9 and 10). ).
A weight 43 is attached to the lower end of the metal chain through a shackle, and a weight against the wind pressure is given.
In the present embodiment, six metal chains 40 are arranged so as to pass through each of the seven pipe groups on the left and right in the column interval.
The metal chain 40 is disposed along the vicinity of the initial introduction portion of the first piping group 11 into which air is introduced. That is, it is suspended at a position close to the wall surface in the air heating chamber 86 at the air inlet portion.
The distance between the metal chain 40 and the heat exchange tube 2 and the wall surface is set at a distance of about several centimeters, and this distance is appropriately set according to the scale of the apparatus.
Since the portion where the metal chain 40 is disposed is where air is introduced, the heat exchange tube 2 and the wall surface are always in a low temperature state, and low temperature corrosion is likely to occur.

The chain mounting rod 41 is locked by a locking bracket 44 fixed to the wall surface of the air heating chamber 86, and is stretched horizontally above the air inlet of the first piping group 11.
Six metal chains 40 are attached to the left and right sides of the chain attachment rod 41 via shackles.
The locking metal fittings 44 are provided at two locations on the wall surface in the air heating chamber and lock the left and right locations of the chain mounting rod 41.
The locking bracket 44 has a U-shaped vertical slide hole 45, and is locked so that the chain mounting rod 41 can move up and down.
In this embodiment, the chain mounting rod 41 moves up and down about 5 cm.

The chain upper and lower arms 42 are projected at three positions at both ends and the center of the rotation shaft on the air introduction portion side.
The chain mounting rod 42 is disposed substantially parallel to the rotational shaft 33, and the chain vertical arm 42 rotates approximately 90 degrees from directly below to the horizontal position as the rotational shaft 33 rotates.
When the chain vertical arm 42 reaches the horizontal direction, the tip portion of the chain vertical arm 42 contacts the chain mounting rod 41 and functions to lift the lower side of the chain mounting rod 41.
The vertical movement of the chain mounting rod 41 is interlocked with the above-described slide drive mechanism, and the distal end portion of the chain vertical arm 42 is connected to the chain mounting rod 41 in conjunction with the rotation of the rotation shaft 33 and the movement of the link frame 35. Lift up.

Next, the operation of the present invention will be described.
When the electric cylinder 31 is operated, the upper and lower pistons 32 slide in synchronism with each other, and the four rotation shafts 33 rotate accordingly.
Since each arm 34 protrudes from the rotation shaft 33, the arm 34 slides the link frame 35.
At this time, since the arm 34 rotates while drawing an arc, the link frame 35 slides while moving up and down according to the rotation locus.
Since the rod 30 is connected to the link frame 35 via the long hole 37, the rod 30 slides on the heat exchange tube 2 and is removed so that dust is scraped off by the weight of the rod 30. Is done.
Since each of the four rods 30 is arranged on the horizontal stage of the heat exchange tube 2, each of the four rods 30 slides in a predetermined area to efficiently remove dust.
Since the slide body (rod 30) is slid while the link frame 35 moves up and down, dust at the connecting portion between the slide body (rod 30) and the slide drive means is also removed, and the weight of the slide body (rod 30) is heat exchanged. The state hung on the tube is maintained.
Although the rod 30 is sandwiched between the link frames 35, it is not fixed. Therefore, the rod 30 can be easily mounted and attached, and is not easily distorted by long-term operation or heat of the apparatus. The trouble of correction etc. is omitted.

During the operation of the air heating chamber 86, air is introduced from the air inlet duct 20 from the left end port of each heat exchange pipe 2 of the first pipe group 11, so that the heat exchange pipe and the wall surface of the inlet portion are at a low temperature.
In the air heating chamber 86, when the dew point is not reached, water vapor is condensed, and there is a risk of reacting with a sulfur component in the exhaust gas to generate a sulfuric acid aqueous solution.
In the present embodiment, since the metal chain is suspended along the vicinity of the initial introduction portion of the air, the combustion gas passing through the air heating chamber 86 is reflected on the metal chain 40, and an air flow is blown from various angles, Dust and condensation around the heat exchange tube 2 and on the wall surface are removed.
In addition, the metal chain 40 is interlocked with the slide drive means, and the rod 30 removes dust from the heat exchange pipe. At the same time, the chain upper and lower arms 42 move the metal chain 40 up and down, so that combustion gas is blown from multiple directions while changing the wind pressure. The entire area around the air inlet of the first piping group 11 is effectively removed.

Although the embodiment of the present invention has been described above, the specific configuration of the present invention is not limited to this embodiment, and changes in the setting and the like within the scope of the invention are included in the present invention. It is.
For example, although the rod 30 is employed as the slide body in the above-described embodiment, the shape of the slide body is not particularly limited, and other shapes can be employed.
Moreover, even if it is a case where a slide body is not provided, it is included in this invention. That is, any configuration in which an airflow changing member (metal chain 40) is provided is included in the present invention.
Moreover, although the metal chain 40 was employ | adopted as an airflow change member in the said Example, the thing made into the elongate shape by connecting a metal piece or a metal piece other than this can also be used as this airflow change member. Further, the present invention includes any structure that employs a function that reflects or changes the airflow gas as the airflow changing member.
In the above-described embodiment, the airflow changing member (metal chain 40) moves up and down in conjunction with the slide driving means. However, another mechanism is adopted as a configuration for moving the airflow changing member (metal chain 40) up and down. Even if it is a case, it is included in this invention.

DESCRIPTION OF SYMBOLS 1 Air heating apparatus 2 Heat exchange pipe 11 1st piping group 12 2nd piping group 13 3rd piping group 14 4th piping group 15 5th piping group 16 6th piping group 20 Blower introduction duct 21 1st communication duct 22 2nd Communication duct 23 Third communication duct 24 Fourth communication duct 25 Fifth communication duct 26 Discharge duct 30 Rod 31 Electric cylinder 32 Piston 33 Rotating shaft 34 Arm 35 Link frame 36 Long hole 37 Long hole 38 Nut 40 Metal chain 41 Chain mounting Rod 42 Chain upper and lower arm 43 Weight 44 Locking bracket 45 Slide hole 80 Stoker furnace 81 Exhaust gas treatment system 82 Garbage pit 83 Garbage popper 84 Recombustion chamber 85 Combustion gas cooling chamber 86 Air heating chamber 87 Decrease tower 88 Dust collector 89 Invitation Blower 90 Chimney

Claims (2)

In an air heating apparatus including an air heating chamber into which combustion gas is introduced, and a heat exchange pipe disposed in the air heating chamber and piped at a predetermined column interval and a predetermined row interval ,
The metal chain is suspended only along the vicinity of the initial introduction part of the piping group that introduces air in the air heating chamber,
The initial stage of the piping group in the air heating device that prevents dust removal, condensation removal and low-temperature corrosion near the initial introduction part of the piping group by using the airflow reflected and changed by the metal chain while moving the hanging metal chain up and down How to prevent low temperature corrosion near the introduction . An apparatus for use in the method of claim 1, comprising:
A metal chain suspended along the vicinity of the initial introduction part of the piping group for introducing air in the air heating chamber,
An apparatus for preventing low-temperature corrosion in the vicinity of an initial introduction portion of a piping group in an air heating device, comprising means for vertically moving the metal chain.