JPH0631320Y2 - Fluidized bed heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an improvement of a fluidized bed heat exchanger.

[Conventional technology]

A conventional fluidized bed heat exchanger of this type has a gas inlet (20a) at the lower end and a gas outlet (20b) at the upper end, as shown in FIG. A vertically extending casing (20), a perforated plate (22) horizontally arranged in the casing (20) and having a large number of vent holes, and a perforated plate (22) in the casing (20). It has a sand layer (23) formed to have an appropriate thickness. Also, the casing (2
In (0), a heat transfer tube (24) consisting of a substantially U-shaped pipe for transferring water as a fluid to be heated has its curved portion (24c) exposed to the outside of the gas flow path (20). The parallel parts (24a) and (24b) are attached so as to penetrate the gas flow path, and one parallel part (24a) is arranged in the sand layer (23) and the other parallel part is arranged.
(24b) is arranged above the sand layer (23). The tip of the one parallel portion (24a) is formed as the water intake port (25), and the tip of the other parallel portion (24b) is formed as the water intake port (26). Further, fins (27) and (27) are attached to the outer surfaces of the parallel portions (24a) and (24b) in order to achieve an efficient heat exchange action.

The gas inlet (20a) is connected to, for example, the exhaust gas discharge system of a diesel engine, and the water inlet of the heat transfer pipe (24).
(25) and the water outlet (26) are connected to, for example, the hot water or steam circulation system of the boiler.

Thus, during operation of the fluidized bed heat exchanger, high-temperature exhaust gas flows through the casing (20) from the gas inlet (20a) to the gas outlet.
It passes toward (20b), but at this time, since the exhaust gas jets from the lower side of the perforated plate (22) into the sand layer (23), the sand layer (23)
Is vigorously stirred and heated to form a fluidized bed.
On the other hand, the two parallel portions (24a) and (24b) of the heat transfer tube (24) are both inside this fluidized bed, and the water flowing into the heat transfer tube (24) from the water intake (25) is While passing through the inside of (24), after being heated by the fluidized bed, it exits from the water outlet (26).

[Problems to be solved by the device]

By the way, the conventional fluidized bed heat exchanger has the following problems.

First, a perforated plate (22) used in the above fluidized bed heat exchanger.
Has a large number of bulges (30) formed by cutting and bending (a type of pressing) as shown in FIGS. 6 and 7.
When forming these bulging portions (30), the same one side edge of each bulging portion (30) is cut open to form a gas ejection hole (31).

Therefore, the exhaust gas ejected from the porous plate (22) flows into the solid particle layer (sand layer) (23) from one direction, so that the solid particle layer is not uniformly layered and the temperature distribution of the fluidized bed is not uniform. The problem is that they are not uniform.

Further, as described above, the porous plate has a problem that both end edges of the gas ejection hole (31) in the bulging portion (30) are easily overheated and burning or the like is likely to occur.

Secondly, since the porous plate (22) has the simple structure as described above, it is composed of a single plate. Furthermore, in order to prevent corrosion due to SOx, NOx, etc. in the exhaust gas, A material having high corrosion resistance (for example, SUS-304) is used. Therefore, the perforated plate (22) is expanded and deformed by the heat from the exhaust gas, and the gap with the heat transfer tube (24) becomes nonuniform. Then, the thickness of the fluidized bed becomes uneven, and the heat recovery efficiency of the heat transfer tube (24) is reduced.

Furthermore, when removing the perforated plate (22) that has been burnt or thermally deformed as described above for replacement, etc., the conventional perforated plate (22) has a single plate structure, and the heat transfer tube (24) is Due to the proximity, it is necessary to remove the perforated plate (22) after removing the heat transfer tube (24). Moreover, since the heat transfer tube (24) is heavy, workability is poor and time consuming. There is a problem.

[Means for Solving the Problems]

The present invention has been made to solve the above-mentioned problems, and a casing (20) having a gas flow passage that allows gas to pass substantially upward from below is provided, and the gas flow passage is blocked in this casing. And a solid particle layer which is formed on the porous plate and has a top surface which is in an open state and which can be in a fluidized state when a gas passes through, and at least a part of the solid particle layer is in contact with the solid particle layer. In a fluidized bed heat exchanger having a heat transfer tube arranged in the gas flow path so that the perforated plate is made of a corrosion resistant material having a coefficient of thermal expansion substantially equivalent to that of the casing, It is configured by connecting a plurality of perforated plate members in a separable manner,
A large number of bulging portions are formed on the surface of the perforated plate whose absorption and strength / improvement of thermal expansion are also achieved by this connecting portion, and slit-shaped gas ejection holes are formed on at least both sides of each bulging portion. It is a fluidized bed type heat exchanger characterized by the above.

[Action]

In the fluidized bed heat exchanger according to the present invention, since the perforated plate is made of a material having substantially the same thermal expansion coefficient as that of the casing, it is possible to prevent the perforated plate from being deformed by heat. Since the perforated plate members are connected to each other, they can be easily taken out from a narrow space, and the rigidity can be increased in this part by connecting them as described above.

Further, since the gas ejection holes in this fluidized bed heat exchanger are formed in a slit shape on at least both sides of each bulging portion, local overheating of the bulging portion does not occur and accidents such as burnout are prevented. can do.

〔Example〕

1 to 4 show an embodiment of a fluidized bed heat exchanger according to the present invention, in which members corresponding to those in FIGS. 5 to 7 are designated by the same reference numerals and are described in detail. The description is omitted.

In the drawing, (1) shows a perforated plate, and (10) shows a heat transfer tube.

The perforated plate (1) is formed in a state where a large number of substantially bulging portions (3) are aligned, and slit-shaped gas ejection holes are formed on both long sides of each of these bulging portions (3). Formed (4). The procedure for forming the gas ejection holes (4) is, for example, when cutting and bending the bulged portion (3) (a type of press working), cutting both long side portions of the bulged portion (3). It can be formed simultaneously by placing. Incidentally, the bulging portion (3) is formed to be convex on the downstream side in the flow direction of the exhaust gas, the slit-shaped gas ejection holes (4), heat transfer particles constituting the solid particle layer (23) The size is set to prevent the passage of the.

Further, the perforated plate (1) is formed by connecting a plurality of perforated plate members (2) in a plane, and the connecting portion has a structure as shown in FIG. That is, each perforated plate member (2)
Bend the edge part that becomes the connecting part of to form the connecting piece (5), and when connecting the porous plate members (2), the connecting pieces (5) of the adjacent porous plate members (2) are overlapped. Both are fastened with bolts etc. At this time, an appropriate spacer (6) may be interposed in the connecting piece (5).

Here, the porous plate (1) is made of a material having heat resistance and corrosion resistance as in the conventional case, but is a material having a coefficient of thermal expansion similar to that of the casing (20). For example, if the casing (20) is made of SS41 material, the perforated plate (1) is made of SUS.
Materials such as 405 and SUH409 are preferred.

The heat transfer tube (10) is made of a substantially U-shaped pipe similar to the conventional one. In this embodiment, the same side ends of a plurality of U-shaped pipes are connected by headers (11) and (12), respectively. I am doing it.
Then, of the headers (11) (12), the lower header (11)
To the water inlet (13) and to the upper header (12) to the water inlet (14)
Is provided. And the two parallel parts (10
A large number of flat fins (15) are attached to a) and (10b) by welding. The fins (15) are fixed as a set of two so as to face each other in the radial direction of each pipe, and in this state, the fins (15) of each set have a substantially rectangular shape centered on the pipe. Has become.

The parallel portions (10a) and (10b) of the heat transfer tubes (10) are arranged in a staggered arrangement.

Further, in this embodiment, the parallel portion (10
At both ends of a) and (10b), the heat exchanger casing (2
Holder member (16a) (16b) for convenience of mounting to (0)
And flange members (17a) and (17b) are provided to connect the heat transfer tubes to each other to form one unit.

Each set of holder and flange member (16a) (17a), (16a) (17
In b), each holder member (16a) (16b) is a curved part of the heat transfer tube (10).
They are provided so as to be on the (10c) side, and the outer dimensions of each of them are set so that the closer to the curved portion (10c) the member is. The casing (20) has window holes (18a) (18b) corresponding to the holder members (16a) (16b). Therefore, by inserting the curved portion (10c) of the heat transfer tube (10) first from the large window (18a) side, the heat transfer tube (1
0) can be installed in a predetermined position, and the workability of attaching and detaching the heat transfer tube at the time of inspection and repair is extremely high.

In the above structure, when the high temperature exhaust gas is introduced into the casing (20) during operation of the fluidized bed heat exchanger, the exhaust gas is ejected from the lower side of the porous plate (1) into the sand layer (23).
Exhaust gas at this time is a large number of bulges (3) on the perforated plate (1).
Since the gas is ejected from each slit-shaped gas ejection hole (4) in two directions, the sand bed (23) is fluidized more uniformly than the conventional fluidized bed heat exchanger, and the temperature distribution of the fluidized bed is also uniform. become.
Furthermore, since the gas ejection holes (4) are formed on both sides of the bulging portion (3) as described above, even if the bulging portion (3) is overheated, the central portion is bent by thermal expansion, so that the curved portion The damage due to the heat of (3) can be prevented.

When the heat exchanger is in operation, the casing (20) and the perforated plate
(1) The whole also undergoes thermal expansion, but since each is made of a material having substantially the same coefficient of thermal expansion, there is almost no dimensional difference between the two. Furthermore, since the perforated plate (1) has a structure in which a plurality of perforated plate members (2) are connected via a connecting piece (5),
This portion absorbs thermal expansion and can suppress dimensional change to a small extent, and since the connecting piece (5) functions as a reinforcing rib, rigidity is improved. That is, since the gap between the heat transfer tube (24) can be kept constant by effectively preventing the deformation of the perforated plate (1) due to heat, it is possible to efficiently recover the heat from the fluidized bed. it can.

Furthermore, in the above heat exchanger, a perforated plate for inspection etc.
When it becomes necessary to remove (1), the perforated plate (1) can be easily removed by dividing it into a plurality of perforated plate members (2) at the connecting portion.

[Effect of device]

As described above, since the gas ejection holes in this fluidized bed heat exchanger are formed in the shape of slits on at least both surfaces of each bulging portion, local overheating of the bulging portion does not occur, and this In the fluidized bed heat exchanger according to the invention, since the perforated plate is formed of a material having a thermal expansion coefficient substantially similar to that of the casing, it is possible to prevent the perforated plate from being deformed by heat, and further Since it is configured by connecting the perforated plate members,
It can be easily taken out even from a narrow space, and the rigidity of this portion can be increased by connecting and constructing as described above. Uniform fluidization of the solid particle layer and uniform temperature distribution of this fluidized bed can improve the heat recovery rate, prevent damage to the perforated plate due to heat, and even if the perforated plate is damaged In cases such as when removing from the casing, it can be easily done.

Therefore, according to the present invention, it is possible to provide a fluidized bed heat exchanger which is capable of recovering heat in a stable manner and can be easily maintained, and which is highly practical.

[Brief description of drawings]

1 to 4 show an embodiment of a fluidized bed heat exchanger according to the present invention. FIG. 1 is a sectional view of a main part, and FIG. 2 is a perspective view showing a structure of a perforated plate. 3 is a perspective view showing the hole shape of the perforated plate, and FIG. 4 is a sectional view of FIG. FIG. 5 is a schematic configuration diagram of a conventional fluidized bed heat exchanger, FIG.
The figure is a perspective view showing a porous plate of a conventional fluidized bed heat exchanger,
FIG. 7 is a sectional view of FIG. (1) ... perforated plate (2) ... perforated plate member (3) ... bulging part (4) ... gas ejection hole (10) ... heat transfer tube (20) ... casing (23) ... solid particle layer

Claims (1)

[Scope of utility model registration request] 1. A casing (20) having a gas flow passage that allows gas to pass substantially upward from below, and a perforated plate () disposed in the casing (20) so as to block the gas flow passage. 1), a solid particle layer (23) formed on the perforated plate (1) and having an open top surface that can be in a fluidized state when a gas passes, and at least a part of the solid particle layer (23 ), A fluidized bed heat exchanger having a heat transfer tube (10) arranged in the gas flow path so that the perforated plate (1) is substantially equivalent to the casing (20). Made of a corrosion-resistant material having a coefficient of thermal expansion of
(2) is configured by connecting in a separable manner, on the surface of the perforated plate member (2), a large number of bulges (3) are formed and slits are formed on at least both sides of each bulge (3). A fluidized bed heat exchanger characterized in that a gas discharge hole (4) in the form of a gas is formed.