JPH0253712B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust heat recovery heat exchanger installed in the exhaust gas flow path of an incinerator for municipal waste.

Conventionally, in this type of device, the heat transfer surface was formed by a group of water tubes penetrating the opposing walls of the exhaust gas passage, so it was not easy to attach and detach, and therefore it was often left in the exhaust gas even for an unnecessary period. For example, when used as a hot water generator for space heating or hot water supply, it is difficult to attach and remove pipes and store removed pipes, even though they are not needed for about two-thirds of the year from spring to autumn. It is usually left unremoved. In order to handle the excess heat absorbed, a cooling tower was operated to cool the system, which was a wasteful process.

In addition, waste incineration exhaust gas is usually below 150°C or 400°C.
Since it is highly corrosive at temperatures above ℃, the life of the heat transfer part was unnecessarily shortened.

In addition, there are problems such as wear due to dust, corrosion, and scale adhesion on the heat transfer section, so detailed inspection of the heat transfer section is essential, but in order to be able to inspect the entire heat transfer surface, The number of manholes had to be increased, and the pipe groups themselves had to be spaced apart more than necessary for heat exchange, resulting in a large device that was not easy to inspect. There were flaws.

An object of the present invention is to provide an exhaust heat recovery heat exchanger that eliminates the above-mentioned drawbacks of the conventional ones and is extremely easy to maintain, inspect, and replace.

The present invention provides an exhaust heat recovery heat exchanger in which a water pipe section 13 is disposed in the exhaust gas passage 9 of an incinerator 2 and heats water with high-temperature exhaust gas.
3 water pipes 10, 11, 12 to the water supply header 16
and the return water header 17, and the environment passage with the check valve 21 is connected to the water supply header 16 and the return water header 1.
A water pipe section 13 including both headers is attached to a movable wall 15 forming a part of the wall of the channel 9, and the water pipe section 13 is connected to the movable wall. This is an exhaust heat recovery exchanger characterized in that it is equipped with a moving device that pulls the exhaust heat outward.

Embodiments of the present invention will be described with reference to the drawings.

Figure 1 is an example of municipal waste incineration equipment.
1 is a food waste supply device, 2 is a fluidized bed incinerator, and 3 is a fluidized bed incinerator.
is a blower, 4 is a heat exchanger for exhaust heat recovery, 5 is a gas cooler, 6 is an electrostatic precipitator, 7 is a fan, and 8 is a chimney.

FIG. 2 is a detailed view of the vicinity of the heat exchanger 4, in which water pipes 10, 11,
A water pipe section 13 consisting of 12 is provided. A portion of the wall of the flow path 9 is provided with a movable wall 15 that is detachably attached by a connecting flange 14, and a water pipe section 13 is fixed to this. Each water pipe 10,1
1 and 12 are formed in a U-shape, each of which has a lower end connected to a water supply header 16 and an upper end connected to a return water header 17.

18 is a water supply source, 19 is a return water tank, 20 is a drain, 21 is a check valve, 22 is a water level contact, 23 is a vent pipe, 36 is a water supply pump, 37 is a check valve, 3
8 is a hot water storage tank.

The water pipe section 13, together with the movable wall 15, the water supply header 16, and the return water header 17, can be horizontally pulled outward by a moving device as described below.

FIG. 3 shows an embodiment of the mobile device. 24 is a trolley as a moving device, and the rail 2 on the horizontal floor
5, so that it can be horizontally reciprocated. Since the movable wall 15 is fixed to the truck 24, the water pipe section 13 can also be horizontally reciprocated together with the truck 24.

During operation, the cart 24 is pushed in and the movable wall 15 is attached to the connecting flange 14 as shown in FIG. is removed from the connecting flange 14, and the trolley 24 is pulled to the state shown in FIG. Since the cart 24 is on the horizontal rail 25, it can be easily moved manually, and the water pipe section 1
3 is pulled out to a place where there are no obstacles or obstacles nearby, making inspection, repair, and replacement operations extremely easy. Tubes and electric wires for water supply, return water, vents, instrumentation, etc. may be removed, but if flexible ones are used, there is no need to remove them.

FIG. 4 shows another embodiment, in which 26 is one beam, 27 is a trolley as a moving device supported horizontally and reciprocably on the lower flange of the I beam by a roller 28, and a moving wall. 15 is hanging. As in the previous embodiment, the water pipe section 13, which is disposed in the flow path 9 during operation, can be easily pulled out by pulling the trolley 27 during inspection.
Repairs, replacements, etc. can be easily performed.

5 and 6 show another embodiment in which the moving device consists of frames 32, 33 connected by three vertical hinges 29, 30, 31. The frames 32, 33 and the movable wall 15 can be folded up by vertical hinges 29, 30, 31, and the movable wall 15 is connected to the connecting flange 1.
It can be installed in the 4th position, or it can be pulled out horizontally and installed in the 5th position.
It is very easy to create the state shown in FIGS. 6 and 6 manually. 34 is a hinge 3 having an elongated hole.
The lid is openably and closably supported by the lid 5, and is used to seal the flow path 9 as necessary when the water tube portion 13 is taken out.

In addition, in the above embodiment, the water pipes 10, 1
All parts of 1 and 12 are installed so that water flows horizontally or upward, so water pump 3
Natural convection occurs even when water pipes 10 and 1 are stopped.
No water vapor accumulates inside 1 and 12, and there is no risk of overheating. Also, the water supply header 16 is operated by the check valve 21.
Since it connects with the return water header 17, the water pipe →
Water circulates from the return water header to the water supply header to the water pipe, making it even more effective at preventing overheating.

The water pipe section 13 is preferably provided at the top of the gas cooler 5. In this part, the exhaust gas temperature is usually 750
The temperature is high, ranging from ℃ to 950℃, and since the flow is turbulent at this location, heat transfer not only by radiation but also by convection increases, making it possible to recover a large amount of heat with a small heat transfer area. In addition, the heat transfer surface temperature also becomes approximately 150 to 300°C, allowing it to escape from the corrosion zone. Therefore, in this range, corrosion protection can be achieved by using aluminized steel obtained by anodizing SS.

In addition, the gas cooler 5 sprays water into the exhaust gas to cool the exhaust gas temperature, but if there is a drift in the exhaust gas, the water spray state breaks down and mist adheres to the wall of the gas cooler, causing scale. If the mist evaporation rate becomes unstable, the gas cooler 5
Inconveniences arise, such as requiring a longer residence time. For this reason, it is necessary to suppress the exhaust gas velocity at the gas cooler inlet and rectify the flow to some extent.

In this respect, the installation example of the heat exchanger 4 as shown in FIGS. 1 and 2 is convenient. In the heat exchanger 4, the speed is 10 to 20 m/s to prevent exhaust gas pressure loss due to the water pipe section 13, abrasion due to dust, and to ensure insertion heat transfer area.
Since the flow velocity is reduced to below, the casing of the water tube group insertion part directly serves as the gas cooler inlet rectifier.

In addition, even if water leaks into the exhaust gas due to water pipe breakage, etc., the gas cooler 5 is designed to spray water, so countermeasures such as using water-resistant castables and detecting water generation are taken. , there is no need to worry about serious accidents. The same applies to the falling of attached scale.

Further, by using the water level contact 22, an alarm can be issued to prevent dry boiling. Note that, instead of using the water level contact 22, dry boiling can be prevented by providing a make-up water line using a ball tap or a constant water level valve.

The present invention provides each water pipe 10, 11, 1 of the water pipe section 13.
2 is arranged in communication with the water supply header 16 and the return water header 17, and an environmental passage with a check valve 21 is provided between the water supply header 16 and the return water header 17 to allow natural circulation, and the water supply header includes both of these headers. A movable wall 1 in which the water pipe portion 13 forms a part of the wall of the flow path 9
5 and which pulls out the water pipe section 13 outward together with the movable wall, natural circulation is maintained between the water supply header and the return water header even when forced circulation is stopped, that is, when the water supply pump is stopped. This not only helps maintain safety and prevents dry heating, but also prevents water vapor from accumulating in the water pipes, eliminating the risk of overheating. It is extremely easy to insert and take out the part into the flow path, and the work can be done in a short time. In addition, it can be removed from the flow path when it is not needed and sealed with another lid during that time, which prevents wasteful heat dissipation and unnecessary contact with exhaust gas, which shortens its life due to corrosion. It is possible to perform maintenance, inspection, and replacement in a place where there are no surrounding objects or objects, and it is also possible to provide an exhaust heat recovery heat exchanger that is compact in size, which has an extremely large practical effect. can play.

[Brief explanation of the drawing]

The drawings relate to embodiments of the present invention; Fig. 1 is a flow diagram of the incineration facility, Fig. 2 is a vertical cross-sectional front view of the vicinity of the heat exchanger, and Figs. 3 and 4 are front views of another embodiment. , FIG. 5, and FIG. 6 are a plan view and a front view of another embodiment. 1... Supply device, 2... Incinerator, 3... Blower, 4... Heat exchanger, 5... Gas cooler, 6...
Electric precipitator, 7...fan, 8...chimney, 9...
Channel, 10...Water tube, 11...Water tube, 12...Water tube, 13...Water tube section, 14...Connection flange, 1
5...Moving wall, 16...Water supply header, 17...
Return water header, 18...Water supply source, 19...Return water tank, 20...Drain drain, 21...Check valve, 2
2...Water level contact, 23...Bent pipe, 24...Dolly, 25...Rail, 26...I beam, 27...
...Trolley, 28...Roller, 29...Vertical hinge, 30...Vertical hinge, 31...Vertical hinge,
32...Frame, 33...Frame, 34...
Lid, 35...Hinge, 36...Water pump, 3
7...Check valve, 38...Hot water tank.

Claims (1)

[Scope of Claims] 1. In an exhaust heat recovery heat exchanger in which a water pipe section 13 is disposed in the exhaust gas passage 9 of the incinerator 2 and heats water with high-temperature exhaust gas, each water pipe 10 of the water pipe section 13 , 11, 12 are arranged in communication with the water supply header 16 and the return water header 17, and an environmental passage with a check valve 21 is provided between the water supply header 16 and the return water header 17 to allow natural circulation. A water pipe section 13 including a header is attached to a movable wall 15 forming a part of the wall of the flow path 9, and the water pipe section 13 is equipped with a moving device that pulls out the water pipe section 13 outward together with the movable wall. Heat recovery heat exchanger. 2. The exhaust heat recovery heat exchanger according to claim 1, wherein the moving device is a reciprocating cart that supports the moving wall and is supported so as to be able to reciprocate on a horizontal rail.