JP2000009395A - Heat exchanger incorporating soot blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the facility area and the manufacturing cost by providing a rotatable lance tube extending through a casing in parallel with heating tubes in the center of a tube bundle and providing an exhaust pipe disposed on the outlet side of the lance tube with a vacuum blower. SOLUTION: A soot blower 1 for removing soot adhering to the surface of heating tubes constituting a heat exchanger comprises a lance tube 3 disposed in the center of a tube bundle 2 in parallel with the heating tubes while penetrating through a casing 7 with a plurality of ejection openings 59 being made over the entire length. A rotary unit 4 for turning the lance tube 3, a rotary joint mechanism 5a and an on/off valve 6 are arranged sequentially at the upstream end part of the lance tube 3 on the outside of the casing 7. A rotary joint mechanism 5b and a shut valve 15 are arranged sequentially at the downstream end 3b of the lance tube 3 and the shut valve 15 is coupled, on the downstream side thereof, with a cooler 10 through an exhaust pipe 9 and with a vacuum blower 12 through a drain tank 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger having a soot blower for removing dust and the like adhering to the surface of a heat transfer tube constituting a heat exchanger.

[0002]

2. Description of the Related Art Boilers for thermal power plants and chemical plants use coal or heavy oil as fuel.
As a recent trend, installation of flue gas desulfurization equipment is an essential condition for environmental measures.

[0003] In these plants, heat is recovered from a high-temperature untreated combustion gas before entering a flue gas desulfurization unit by a heat exchanger, this is stored in a heat medium, and then processed after desulfurization using the stored heat. Generally, a gas-gas heater (hereinafter, referred to as GGH) is provided to increase the gas temperature and increase the diffusion efficiency of the gas released to the atmosphere.

FIG. 7 shows a system configuration of the GGH. In FIG. 7, the high-temperature untreated combustion gas 32 generated in the boiler 31 is introduced into a heat recovery device 33, where the heat is recovered, the temperature is reduced, and then guided to a desulfurization device 34.

[0005] The desulfurization unit 34 is usually a wet type device, in which the sulfur contained in the untreated combustion gas 32 is removed to form a clean treatment gas 35, which is reheated by a reheater 36, Released and diffused into the atmosphere.

On the other hand, a heat medium 39 is forcibly circulated by a pump 40 in a tube bundle 38 constituting the heat recovery unit 33 and the reheating unit 36.

In the heat recovery unit 33, the recovered heat is accumulated in the heat medium 39 and sent to the reheater 36, where it reheats the low-temperature processing gas 35 and discharges it from the chimney 37 to the atmosphere. I do.

Each of the tube bundles 38 constitutes one unit of heat exchanger, and details thereof are shown in FIGS. 8 shows a plan view, FIG. 9 shows a side view, and FIG. 10 shows a cross section taken along line AA of FIG.

In the figure, holes are opened at an appropriate pitch in spacers 42a and 42b fixed by a frame 41,
The heat transfer tubes 43 penetrate through the holes of the spacers 42a and 42b.
Are arranged in large numbers.

A header 44a is provided at the uppermost stage of the tube bundle 38, and the uppermost heat transfer tube 43 is connected to the header 44a so as to communicate in parallel. Similarly, a header 44b is provided at the lowermost stage, and the lowermost heat transfer tubes 43 are connected in parallel. The headers 44a and 44b are provided with one nozzle 45a and 45b, respectively.

The heat medium 39 flowing into the header 44b from the nozzle 45b is transferred from the lowermost heat transfer tube 43 to the uppermost heat transfer tube 4
3, the heat transfer tubes 43 are connected by a U-joint 46 so as to flow out to the header 44a to form a continuous conduit.

In the heat transfer tube 43, a heat medium 39 flows inside the tube, and a combustion gas 32 or a processing gas 35 flows outside the tube in a direction orthogonal to the heat transfer tube 43 to perform heat exchange. At this time,
Since the outside of the tube (gas) is lower than the heat transfer coefficient of the inside of the tube (heat medium), fin tubes are often used to increase the heat transfer area. Is sometimes used.

By the way, generally, the combustion gas 32 generated in the boiler 31 using coal or heavy oil as a fuel contains a large amount of dust. When this dust adheres to the heat transfer tube 43, the heat transfer performance is significantly reduced. In addition, the gas flow resistance increases. Further, when the dust accumulates on the heat transfer tube, it causes clogging, and eventually stops functioning as a heat exchanger.

Accordingly, the heat recovery unit 33 and the reheater 36 shown in FIG. 7 always maintain stable performance.
It is necessary to constantly remove the dust adhering to the surface of the heat transfer tube 43, and a soot blower is usually used to achieve this purpose.

FIGS. 11 to 13 show the configuration of a general soot blower. In these figures, the soot blower 47
Is inserted into the casing 49 and the tube bundle 3
Lance tube 48 arranged in parallel with
A rotary device 52 provided on the insertion port side of the lance tube 48 for rotating the lance tube 48, a rotary joint mechanism 50, and an on-off valve 53.

The lance tube 48 has a plurality of columns 5 at a plurality of positions in the longitudinal direction.
4, is rotatably supported by a support bearing 55, and a plurality of injection ports 59 are opened at an appropriate pitch in the longitudinal direction so as to face the tube bundle 38. It is sealed with a plug.

The soot blower 47 is connected to a piping of an injection medium (not shown) by a flange 51, and high-pressure steam or compressed air is usually used as the injection medium.

In FIG. 11, when the on-off valve 53 is opened, a high-pressure injection medium is injected into the injection port 59 provided in the lance tube 48.
Thus, the dust adhering to the surface of the heat transfer tube 43 disposed in the tube bundle 38 is removed at an appropriate spray angle.

The pitch, diameter, etc. of the injection ports 59 provided in the lance tube 48 are determined so that dust can be effectively removed over the entire length of the heat transfer tube 43.

It is to be noted that the rotating device 52 is rotated in one direction for dust removal in the vertical direction of the tube bundle 38 so that the tube bundle 38 shown in FIG.
As shown in a representative example in FIG. 3, as shown by an arrow in the injection direction, the dust is removed by automatically opening the on-off valve 53 only during θ set as the effective injection angle required for dust removal.

By the way, when the soot blower 47 is activated, the lance tube 48 is at the gas temperature. At this time, when high-temperature, high-pressure steam as an injection medium is jetted, it is cooled and a large amount of drain is generated. When compressed air is used as the injection medium, a condensed drain flows in.

When these drains fall on the heat transfer tube 43, the dust adhering to the surface thereof is fixed.
It is difficult to remove. In addition, the drain reacts with sulfur and other harmful elements contained in the medium to produce components such as sulfuric acid that significantly corrode metals.

For this reason, conventionally, at the time of start-up, measures have been taken to prevent the drain from descending to the tube bundle 38 as much as possible and to collect the generated drain and discharge it to the outside of the system at the time of startup. .

That is, in FIG. 12 and FIG. 13, a gutter 57 fixed by welding or the like to a bracket 56 fixed to the support bearing 55 is inclined so that the drain easily flows below the lance tube 48. Attached.

A drain hole is provided at the lowest part of each gutter 57, and a drain pipe 58 is provided so as to communicate with each drain hole. The drain pipe 58 collects the drains of the gutters 57 of each stage. The casing 49 is configured to be discharged outside the casing 49.

[0026]

As described above, in the conventional soot blower, it is necessary to install the soot blower 47 at a distance outside the tube bundle 38 as a countermeasure against drainage generated at the time of starting. Space becomes big.

In addition, in order to effectively remove dust from each tube bundle 38, it is necessary to eject a jetting medium from both sides of each tube bundle 38, so that the number of soot blowers to be installed increases. For example, as shown in FIG. 13, when the tube bundles 38 are of two series, soot blowers are required by (2 + 1) × the number of stages.

Further, in order to cope with the poor use environment in the casing 49, many facilities such as a gutter 57 and a drain pipe 58 are required, which leads to an increase in the area of the facility and an increase in the production cost. It had the following.

It is an object of the present invention to provide a heat exchanger with a built-in soot blower which solves such problems in the conventional apparatus and reduces the equipment area and the manufacturing cost. It is assumed that.

[0030]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a lance tube extending through a central portion of a tube bundle, extending parallel to a heat transfer tube, and penetrating a casing. , Provided at both ends of the lance tube,
A valve for opening and closing the flow path of the injection medium, a rotating device provided at one end of the lance tube for rotating the lance tube, and a vacuum blower connected to an exhaust pipe provided on the outlet side of the lance tube. The present invention provides a heat exchanger with a built-in soot blower.

That is, according to the present invention, the lance tube selects the central portion of the tube bundle, is arranged so as to extend in parallel with the heat transfer tube, and is configured to rotate at this position. Since soot and dust can be removed by injecting the injection medium into the heat transfer tubes around the lance tubes, the number of required lance tubes and the installation space can be reduced.

Further, according to the present invention, the lance tube is provided with a cover tube so as to be a double tube with the lance tube, a mechanism for sliding the cover tube in the axial direction is provided, and the lance tube and the cover tube are provided. An object of the present invention is to provide a heat exchanger with a built-in soot blower, each of which is provided with a jet port having the same pitch.

That is, according to the present invention, the cover pipe can be slid to switch the cover pipe and the lance pipe to the opening position where the ejection medium ejection port of the lance pipe coincides with the closed position of the lance pipe that does not coincide with the ejection medium ejection port. In some cases, the outlet of the lance tube is surely closed, so that the vacuuming operation by the vacuum blower becomes more reliable, and the possibility that the drain is ejected out of the tube is completely eliminated.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 is a system configuration of a soot blower according to the present embodiment, FIG. 2 is a sectional view taken along line AA of FIG. 1, FIG. 3 is an arrangement of a lance tube in the tube bundle, FIG. 4 is a sectional view of a lance tube of the soot blower, and FIG. 4 AA cross section,
FIG. 6 shows a state where the injection port is closed by a cover tube.

As shown in FIG. 1, the soot blower 1 is disposed at the center of the tube bundle 2 in parallel with the heat transfer tube 43, and further, the lance tube 3 penetrating through the casing 7.
A rotary device 4 and a rotary joint mechanism 5 provided outside the casing 7 at the upstream end 3 a of the lance tube 3.
a, an on-off valve 6, a rotary joint mechanism 5 b provided at a downstream end 3 b of the lance tube 3, and a shutoff valve 15.

The lance tube 3 is provided with a plurality of injection ports 59 for ejecting the injection medium at an appropriate pitch over the entire length, facing the tube bundle 2. The upstream end 3a of the lance tube 3 is connected to a flange 5 upstream of the on-off valve 6.
1 is connected to the piping of the injection medium. Further, the lance tube 3 is provided with bearings 13 mounted on both sides of the casing 7.
a and 13b rotatably supported and sealed.

The downstream end 3b of the lance tube 3 is connected to a shutoff valve 15
Is connected to an exhaust pipe 9 on the downstream side of the cooler 1.
The vacuum blower 12 is connected to the vacuum blower 12 via a zero and a drain tank 11.

The lance tube 3 configured as described above is
As shown in FIG. 2, one tube bundle 2 is arranged at the center of each tube bundle 2.

In order to show the arrangement of the heat transfer tubes 43 in one tube bundle 2 in detail, the cross section BB of FIG.
Shown in As shown in FIG. 3, in the present embodiment, a space for inserting the lance tube 3 is secured in a central portion of the tube bundle 2 by omitting a part of the heat transfer tube.

Each of the heat transfer tubes 43 connects the adjacent heat transfer tubes 43 at both ends thereof with a U-joint 46.
Is omitted, for example, the heat transfer tube 43p is connected to and connected to the tube end of the heat transfer tube 43q at the opposite tube end as shown, so that all of the heat transfer tubes 43 communicate in series.

The heat transfer tubes 43 are supported inside the tube bundle 2 by holes formed in the spacers 14 provided at appropriate intervals in the length direction to support the heat transfer tubes 43.

Next, the lance tube 3 constituting the soot blower 1
4 and 5 are shown in FIGS. Keys 18a and 18b are fixed to both ends of the lance tube 3. The components of the rotating device 4 for rotating the lance tube 3 and the rotary joint mechanisms 5a and 5b are as described above.

A cover tube 17 is provided concentrically outside the lance tube 3.
Are provided, and tube heads 19a and 19b are fixed to both tube ends of the cover tube 17 by welding or the like. The tube heads 19a and 19b have keyways 18 as shown in FIG.
c and 18d are processed, and these are fitted with the keys 18a and 18b, whereby the independent rotation of the cover tube 17 in the rotation direction is restricted, and the cover tube 17 is mounted slidably in the axial direction.

The tube head 19a is provided with a mechanism for sliding the cover tube 17. That is, the thrust bearing 20 is fixed to the pipe head 19a, and its outer ring is supported by the support claw 23, and this is connected to the shaft end of the telescopic device 24 fixed to the casing 49.

The cover tube 17 is rotatably supported by a bearing 21 fixed to a casing 49 and is sealed at the same time. Further, slidable sealing materials 22a, 22a, 2
2b is attached.

The situation at the time of startup of the above-described embodiment of the present invention will be described. At the time of startup, the on-off valve 6 is in a closed state. In this state, the shutoff valve 15 is opened to start the vacuum blower 12, and the lance tube 3 is opened to the lance tube 3 by maintaining the inside thereof at a negative pressure. Atmosphere is sucked into the lance tube 3 from the ejected orifice 59.

When the on-off valve 6 is opened in this state, the injection medium, that is, steam or compressed air flows into the lance tube 3, mixes with the above-mentioned air sucked while being drained, and passes through the exhaust pipe 9. To the cooler 10.

The cooler 10 is cooled by the cooling water 16, where the drain is actively generated, and the drain tank 1 is cooled.
Collect in 1. As a result, the vacuum blower 12 sucks only the gas, so that troubles caused by sucking the drain can be prevented.

This operation state is continued for an appropriate time, and when the preheating of the injection medium piping and the soot blower 1 is sufficiently achieved and the generation of drain is stopped, the shut-off valve 15 is closed to operate the vacuum blower 12. Stop. afterwards,
The rotating device 4 is operated to start the normal operation of the soot blower 1.

By the above operation, it is possible to start the tube bundle 2 without draining the same. When the steady operation is started, the lance tube 3 is operated by the rotation device 4 at the center of the tube bundle 2 as shown in FIG. Therefore, the heat transfer tube 43 is rotated in one direction at a constant rotation speed, and the ejection medium is constantly ejected from the ejection port 59 to efficiently remove dust from the heat transfer tube 43 in all directions (360 degrees).

On the other hand, the details of the lance tube 3 will be described below. When the cover tube 17 is set to the operating position by the expansion and contraction device 24 in the normal operation, the ejection port 59 opened in the lance tube 3 coincides with the ejection port 59 opened in the cover tube 17, and the ejection medium is ejected. The dust in the tube bundle 2 is spouted from the port 59.

When the rotation device 4 is operated to rotate the lance tube 3, the rotation force is applied to the keys 18a, 18b, the key grooves 18c,
The power is transmitted to the cover tube 17 through the connection pipe 18d, and the injection port 59 rotates while being aligned, and dust can be removed over the entire circumference.

The ejection port 59 of the cover tube 17 is made larger than the ejection port 59 of the lance tube 3 in consideration of the ejection angle of the ejection medium.

When the ejection of the ejection medium is stopped at the time of activation, the expansion device 24 is operated as shown in FIG. Is shifted.

As a result, the operation of evacuating the vacuum blower 12 becomes more reliable, and the possibility that the drain is ejected outside the pipe by closing the injection port 59 is completely eliminated.

As described above, according to this embodiment, the arrangement of the tube bundles 2 can be made compact, the efficiency of dust removal can be improved, and the cost of equipment and operation can be reduced.

Although the present invention has been described with reference to the illustrated embodiment, the present invention is not limited to this embodiment.
It goes without saying that various changes may be made to the specific structure within the scope of the present invention.

[0058]

As described above, according to the present invention, a lance pipe extending through the central portion of the tube bundle and extending in parallel with the heat transfer pipe is provided at both ends of the lance pipe, and the flow path of the injection medium is provided. And a valve for opening and closing the lance, provided at one end of the lance tube,
Since the soot blower built-in heat exchanger is configured to include a rotating device that rotates the lance pipe and a vacuum blower connected to an exhaust pipe provided on the outlet side of the lance pipe, a central part of the tube bundle is selected. The lance tube which extends and is arranged so as to be parallel to the heat transfer tube, and rotates at this position, enables the injection medium to be injected into the heat transfer tube around the lance tube to remove soot and dust. The reduction in the number of pipes and installation space has contributed to a significant contribution to cost savings by saving space and equipment.

According to the invention described in claim 2, the lance tube is provided with a cover tube so as to be a double tube with the lance tube, and a mechanism for sliding the cover tube in the axial direction is arranged. In addition, since the lance pipe and the cover pipe are each provided with the same pitch of the discharge ports to constitute the soot blower built-in heat exchanger, at the time of start-up, the cover pipe is slid to eject the injection medium of the cover pipe and the lance pipe. By switching from the open position where the outlets match to the closed position where the outlets do not match, the outlet of the lance tube is reliably closed, the vacuum blower is more reliably evacuated, and there is no possibility of draining out of the tube. Thus, a highly reliable device with stable operation can be obtained.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a heat exchanger with a built-in soot blower according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view of a lance tube of the soot blower according to the embodiment.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a cross-sectional view showing one operation state of the lance tube in the embodiment.

FIG. 7 is a system configuration diagram of a conventional general gas / gas heater.

FIG. 8 is a plan view showing a tube bundle of the heat exchanger included in FIG. 7;

FIG. 9 is a side view of the heat exchanger tube bundle of FIG. 8;

FIG. 10 is a sectional view taken along line AA of FIG. 9;

FIG. 11 is a plan view showing a conventional heat exchanger having a soot blower.

FIG. 12 is a sectional view taken along line AA of FIG. 11;

FIG. 13 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Soot blower 2 Tube bundle 3 Lance pipe 4 Rotating device 5a, 5b Rotary joint mechanism 6 On-off valve 7 Casing 9 Exhaust pipe 10 Cooler 11 Drain tank 12 Vacuum blower 13a, 13b Bearing 14 Spacer 15 Shutoff valve 16 Cooling water 17 Cover pipe 18a , 18b Key 18c, 18d Keyway 19a, 19b Pipe Head 20 Thrust Bearing 21 Bearing 22a, 22b Sealing Material 23 Support Claw 24 Telescopic Device 31 Boiler 32 Combustion Gas 33 Heat Recovery Device 34 Desulfurization Device 35 Processing Gas 36 Reheater 37 Chimney 38 Tube bundle 39 Heat medium 40 Pump 41 Frame 42a, 42b Spacer 43 Heat transfer tube 44a, 44b Header 45a, 45b Nozzle 46 U joint 47 Soot blower 48 Lance tube 48a Tube end 49K Ring 50 rotary joint mechanism 51 flange 52 rotating device 53 on-off valve 54 struts 55 support base bearings 56 bracket 57 trough 58 drain pipe 59 injection ports

Claims (2)

[Claims] 1. A lance tube passing through a central portion of a tube bundle and extending parallel to a heat transfer tube; a valve provided at both ends of the lance tube for opening and closing a flow path of an injection medium; A soot blower built-in heat exchanger, comprising: a rotating device provided at one end of the lance tube for rotating the lance tube; and a vacuum blower connected to an exhaust pipe provided on the outlet side of the lance tube. . 2. The lance tube is provided with a cover tube so as to form a double tube with the lance tube, a mechanism for sliding the cover tube in the axial direction is arranged, and the lance tube and the cover tube have the same pitch. The heat exchanger with a built-in soot blower according to claim 1, wherein the heat outlet is provided.