JPH0942646A - Method and apparatus for removing dust of heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method or an apparatus for removing dust which prevents soots being accumulated on an internal surface of a flue to simplify or facilitate the removal of the soots accumulating in the flue composing a heat exchanger provided in the flue. SOLUTION: In a heat exchanger 30 having a number of flues, a gas nozzle 37f is opened at an opening part of each flue to eject a high pressure gas pulsingly at a short interval to the opening part from the gas nozzle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger that is mainly installed in a flue of a boiler or an incinerator and transfers heat of flue gas, and particularly to soot and dust accumulated in the flue of the heat exchanger. The present invention relates to a dust remover for removing dust.

[0002]

2. Description of the Related Art In general, it is known to use a heat exchanger in a flue such as a boiler or to install a heat exchanger in the flue in order to cool the flue gas. Also, regardless of whether the heat exchanger installed in the flue is a smoke pipe type or a water pipe type, soot dust accumulates on the part forming the flue, so clean and remove it manually at specified intervals. There is.

[0003]

However, the content of the work is that the inspection window of the heat exchanger is opened, and the spatula attached to the tip of the metal rod is thrust from there and scraped off, or a person enters inside and hammers. The work environment was poor and work efficiency was poor because it was shaved off with a chisel. Further, in recent years, it has been proposed to spray ultra-high pressure water to remove soot and dust attached by a so-called water chisel, but since water is used, it is difficult to prevent rusting and maintenance. That is, according to the present invention, a dust removing method or apparatus for preventing soot dust from accumulating on the inner surface of the smoke pipe in order to simply or easily remove soot dust that accumulates on the smoke pipe constituting the heat exchanger provided in the flue The purpose is to obtain.

[0004]

According to the present invention, in the heat exchanger having a large number of smoke pipes, gas nozzles are opened at the openings of the smoke pipes, and high-pressure compressed air is discharged from the gas nozzles. It is solved by a method of ejecting pulses into an opening in short pulses, and a device comprising a controller embodying such a method.

[0005]

The flue gas passes through the smoke pipe forming the flue while the heat exchanger is operating, and the soot and dust contained in the flue gas is kept attached. On the other hand, when the heat exchanger is operating,
High-pressure compressed air is sent from the gas nozzle to the smoke tube, and the soot that adheres to the smoke tube is eliminated by the pressure wave. Since the injected compressed air is sent in pulses, it is less likely to be attenuated in the space from the gas nozzle to the smoke tube. Further, the soot is subjected to a stronger impact than the steady flow due to the impact of the pressure wave, and is separated from the inner surface of the smoke tube. The pulsed compressed air may be supplied from the upstream side or the downstream side of the smoke pipe.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. In FIG. 1, reference numeral 10 is a waste incinerator utilizing the present invention. The incinerator 10 has an incinerator 20 and a flue 11 connected to it. The flue 11 includes a first heat exchanger 12 serving as a water heater, a second heat exchanger 30 serving as an exhaust air cooler, a bag filter 14, an exhaust fan 16, and a chimney 18 with a steel tower.
And the like, and the downstream end thereof, that is, the upper end of the chimney 18 is open to the atmosphere.

The incinerator 20 has a combustion chamber 21. 21a
Is an input port for inputting waste to the combustion chamber 21,
Pusher 2 that doubles as a storage box for the incineration object at the inlet 21a
2 is attached. Reference numeral 21b is a furnace bottom forming a bottom surface of the combustion chamber 21. The furnace bottom 21b is movable, and the incineration object charged into the combustion chamber 21 moves from the charging port 21a to the ash outlet 21c and burns. The burnt gas generated by the combustion of the incineration object rises and is discharged to the flue 11 through the exhaust port 23 provided at the top of the furnace. Reference numeral 24 is a conveyor for conveying the discharged ash to the ash box 25.

The first heat exchanger 12 cools the burnt gas discharged from the incinerator 20 and at the same time supplies hot water by utilizing the exhaust heat thereof, and constitutes a smoke tube type boiler, that is, a water heater. . Reference numeral 13 is a steam chimney for discharging excess water vapor into the atmosphere.

The second heat exchanger 30 is a smoke tube type heat exchanger composed of a large number of smoke tubes 31, 31 surrounded by an outer shell 34 arranged in a horizontal direction. The flue gas guided by the smoke pipe 11 flows from the inflow pipe 32 at the left end to the outflow pipe 33 at the lower end. It should be noted that the fact that the second heat exchanger 30 is horizontal is not an essential requirement in the structure of the invention and may be vertical.

The bag filter 14 has a filter portion 14a at the top.
And a dust hopper 14b in the lower portion, and the flue gas containing soot dust flows in from the lower inlet 14c, is filtered inside, and is discharged from the upper outlet 14d. The basic structure is not so different from the conventionally known one. 14e is a screw feeder for discharging the removed dust, and 14f is a dust box.

Thus, the high temperature flue gas sucked from the incinerator 10 by the suction force of the exhaust fan 16 and the chimney 18 is the first
It is water-cooled by the heat exchanger 12, acts as a heat source for the water heater, is air-cooled by the second heat exchanger 30, and is cooled to an appropriate temperature by the bag filter 14 described later. Then, the bag filter 14 removes fine dust and chlorides, and then is discharged into the atmosphere by the forced flow provided by the exhaust fan 16 and the natural flow provided by the chimney 18.

Next, the essential parts of the present invention will be described with reference to FIGS. The second heat exchanger 30 has a thick tubular outer shell tube 34 having a quadrangular cross section, and inside thereof, as described above, a thick inflow tube 32 at the upper end and a thick outflow tube 33 at the lower end.
A large number of smoke pipes 31, 31 that connect between and are arranged. 30a is a mount for supporting the second heat exchanger 30.
Since the inflow pipe 32, the outflow pipe 33, and the outer shell pipe 34 have substantially the same connection relationship, the inflow pipe 32 will be described as a representative of both pipes. Square overhang 32b and round flange 3
A rounded member 32a having 2c is coupled via a square flange 32d. 39 is the second heat exchanger 30
Is a roof for protecting the roof 39 from rainwater, and 39a is a stay for holding the roof 39.

The smoke pipes 31, 31 are made of SGP material (steel pipe for piping) of size 50A defined by Japanese Industrial Standards, and as shown in FIG. 4, five pipes are arranged in the vertical direction,
These are arranged in four rows in the horizontal direction. 35 is an outer shell 34
Is a refrigerant passage formed inside the
It is formed between 1. The refrigerant passage 35 has an inflow port 35a.
A cooling medium such as water or air is formed between the exhaust pipe 35 and the outlet 35b to cool the outer surfaces of the smoke pipes 31, 31. Reference numeral 36 denotes a dust removing device, which is a main part of the ventilation pipe 37.
Is installed on either the inflow pipe 32 or the outflow pipe 33, or is installed across the flue 11 at a position 15 to 20 cm away from the end of the smoke pipe 31 supported by the outer shell pipe 34.

The ventilation pipes 37 forming the dust removing device 36 are made of steel or stainless steel pipe material, and are provided for each row of the four smoke tubes 31, 31 arranged in the lateral direction. Each ventilation pipe 37, 37 is a size 20A specified by Japanese Industrial Standards.
Made of SGP material of which the inner end is closed and the outer end is led out to the outside of the inflow pipe 32 through the flange 37a,
It communicates with a common pressure source 37b. The pressure source 3
7b, as shown in FIG. 5 (b), a pulse control means 37c including an electric timer and its pulse control means 37c.
An electromagnetic air damper 37e operated by a signal emitted from the device and 5 to 6 kg / square centimeter (0.5 to
The air tank 37d stores compressed air compressed to 0.6 megapascals. Further, on one side of the ventilation pipe 37, the diameter is 5 to 9 mm, preferably 6 to 7 mm, toward the opening of the smoke pipes 31, 31 on the same axis as this.
The gas nozzle 37f is drilled and opened.

When the dust removing device 36 operates, the air tank 3
7d is filled by an air pump (not shown), and the compressed air sent from there is sent to the ventilation pipe 37 for a period and time set by the pulse control means 37c and directed from the gas nozzle 37f to the inner surface of the smoke pipe 31, 31. Is jetted. In this embodiment, if the time and timing of the compressed air are shown by taking the first ventilation pipe 37f1 in FIG. 5 (a) as an example, the time T of the compressed air is set to 0.1 to 0.15 seconds. Further, the injection is performed with pulses having substantially equal intervals with a cycle time S of 2 to 3 minutes. And 4
The ventilation pipe 37 of the book is paused for three injections of the other tube each time it is injected. The pressure of these compressed air and the gas nozzle 37f
It is preferable that the opening area and the time for ejecting the compressed air are set so that the dust removal effect on the inner surface of the smoke pipe 31 can be maintained and the continuous operation can be performed. In this embodiment, it is shown in the figure that three of the four ventilation pipes 37 are set so as to alternately rest. By providing a pause in this way, it is possible to maintain a 100% removal efficiency of the dust adhering to the inner surface of the smoke pipe 31 while continuously operating using the pause smoke pipe.
Moreover, almost the same effect could be confirmed regardless of whether the injection direction was forward flow or backward flow.

In this way, the velocity of the air jetted from the gas nozzle 37f toward the inner surfaces of the smoke tubes 31, 31 reaches about 200 m / sec, and a strong pressure wave is generated to scrape the inner surfaces of the smoke tubes 31, 31. Passes while acting like.
Therefore, even if the flue gas passing therethrough contains soot dust, it does not adhere to the inner surface of the flue, and if any adheres, it is removed. In the above description, it goes without saying that the term heat exchanger used is a concept including various heat exchangers such as a flue cooling device and a water heater provided in the flue.

[0017]

As described above, according to the present invention, the amount of soot adhering to the smoke tube is small, and since it is frequently performed in a pulsed manner, unlike the steady flow such as exhaust gas, the smoke tube Dust is removed relatively easily because it gives a strong impact to the inner surface. Further, since it is constantly removed by the compressed air, it is not necessary to remove it manually, and continuous operation is possible. further,
Since the dust is removed by the pressurized air, the smoke tube is not wetted as compared with the case where the dust is removed by the pressurized water, and the maintenance is easy.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention and is a system diagram showing a part of a waste incinerator in a cutaway manner.

FIG. 2 is a side view showing a part of a second heat exchanger, which is a main part, in a cutaway manner.

FIG. 3 is an enlarged cross-sectional view showing an enlarged main part thereof.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 (a) is an operation explanatory view of pulse control means, and FIG.
FIG. 3 is a configuration diagram of pulse control means.

[Explanation of symbols]

10 ... Incinerator 11 ...
Flue 12 ... First heat exchanger 13 ...
Steam chimney 14 ... Bug filter 14a ...
Filtering unit 14b ... Dust hopper 14c ...
Inflow port 14d ... Outflow port 14e ...
Screw feeder 14f ・ ・ ・ Dust box 16 ・ ・ ・
Exhaust fan 18 ・ ・ ・ ・ Chimney 20 ・ ・ ・
Incinerator 21 ... Combustion chamber 21a ...
Input port 21b ... Furnace bottom 21c ...
Ash outlet 22 ・ ・ ・ ・ Pushing machine 23 ・ ・ ・
Exhaust port 24 ... Conveyor 25 ...
Ash box 30 ... Second heat exchanger 30a ...
Frame 31 ... Smoke pipe 32 ...
Inflow pipe 32a ... Rounded member 32b ...
Overhanging part 32c ... Round flange 32d ...
Square flange 33 ... Outflow pipe 34 ...
Outer shell tube 35 ... Refrigerant passage 35a ...
Inlet 35b ... Outlet 36 ...
Dust remover 37 ... Vent pipe 37a ...
Flange 37b ... Pressure source 37c ...
Pulse control means 37d ... Air tank 37e ...
Air damper 37f ... Gas nozzle 39 ...
Roof 39a ... Stay

Claims (4)

[Claims] 1. A heat exchanger having a large number of smoke tubes, characterized in that a gas nozzle is opened toward an opening of each smoke tube, and high-pressure compressed air is ejected from the gas nozzle in a pulsed form for a short time. How to remove dust. 2. The dust removing method according to claim 1, wherein the gas nozzle and the compressed air ejected from the gas nozzle have a flow velocity at a central portion of the compressed air ejected from the gas nozzle in a subsonic region of 150 m / sec or more. 3. A heat exchanger having a large number of smoke tubes, comprising a control device which opens gas nozzles toward the openings of the respective smoke tubes and ejects high-pressure compressed air from the gas nozzles in short pulses. Dust removal device. 4. A dust removing method and a dust removing apparatus according to claim 1, wherein the pulses of the compressed air injected from the plurality of gas nozzles are provided with intermittent rest periods.