JPH0319476B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a shell-and-tube heat exchanger used for recovering heat from exhaust gas discharged from various industrial furnaces.

(Prior art) Conventional shell-and-tube heat exchangers use stainless steel pipes as heat transfer tubes through which the fluid to be heated flows, so the allowable heat resistance temperature is approx.
800℃, and even considering internal cooling by airflow, it cannot be used for heat exchange with exhaust gas at a temperature of 1000℃ or higher. Also, stainless steel pipes are easily corroded by exhaust gas, so the composition of the exhaust gas cannot be used. As a result, it has the disadvantage that its range of use is greatly limited. Therefore, attempts have been made to use ceramic tubes, which have excellent heat resistance and corrosion resistance, as heat transfer tubes, but ceramic tubes cannot be welded to support walls like metal tubes, and they are manufactured more easily than metal tubes. Because the above dimensional error is large, exhaust gas or heated fluid is likely to leak from between the support wall and the support wall, and if it is firmly attached to the support wall to prevent leakage, thermal stress may occur because it is more brittle than a metal pipe. It had various drawbacks such as being easily damaged.

(Objective of the invention) The present invention solves these problems and can be used for exhaust gas with a high temperature of 1000°C or more or corrosive exhaust gas, and moreover, it prevents leakage of exhaust gas etc. and heat exchanger tubes. It was completed with the aim of creating a heat exchanger that would not be damaged.

(Structure of the Invention) The present invention provides a heat exchanger in which a large number of through holes communicating with a supply port and an outlet of a fluid to be heated are arranged on opposing walls of a frame whose inside is formed into a heat transfer fluid flow path. In the container, a wall is provided on both sides of the frame, in which wall structures having through holes communicating with each through hole are stacked up in a slidable manner, and an internal space is formed between the opposing wall structures of the wall. A plurality of ceramic tubes each having a center hole and a radial partition wall into which a ceramic fluid is inserted are provided, and the heating fluid inflow side of each ceramic tube is provided with a tube that expands and contracts in the axial direction of the ceramic tube. This device is characterized by a compression spring that absorbs the amount of water, and is provided in pressure contact with the ceramic tube.

Next, the present invention will be explained in detail with reference to the illustrated embodiment. In the figure, reference numeral 1 denotes a metal frame having openings on both upper and lower sides, and the inside of which is formed as a flow path for heat transfer fluid such as high-temperature exhaust gas. A supply port 3 for the fluid to be heated is provided on the outside of the opposing wall surface 2 and wall surface 2' of the frame body 1.
A fluid inflow chamber 3' with a fluid inflow chamber 3' and a fluid outflow chamber 4' with an outflow port 4 are provided. 5 is a ceramic tube made of a ceramic material with excellent heat resistance and corrosion resistance, such as silicon carbide, and preferably has flanged or spiral fins 6 formed on its surface to increase the heat transfer area. Both ends of these ceramic tubes 5 are kept in communication with the through holes 11, 11' of the hexagonal columnar wall structures 7, 7', and the outside of the wall structures 7, 7' is connected to the supply port 3. The wall surfaces 2, 2' are maintained in communication with the metal support tubes 8 and 9, one end of which is inserted into and supported by a large number of through holes 10, 10' provided in the wall surfaces 2, 2' so as to communicate with the outlet 4. A large number of ceramic tubes 5 are installed in parallel and perpendicular to the heat transfer fluid flow path formed in the frame 1, and the wall structures 7 and 7' are slidable with their outer surfaces in contact with each other. Walls 7a and 7a' are provided on both sides of the frame 1 so as to be stacked freely. The wall structures 7, 7' are made of a ceramic material such as silicon carbide like the ceramic tube 5, and through holes 11, 11', which are equal to the inner diameter of the ceramic tube 5, are provided in the axial direction in the center thereof. The joint surfaces 12, 12' between each wall structure 7, 7' and the ceramic tube 5, and the wall structure 7,
The joint surfaces 13, 13' between the support tubes 8, 9 and the frame 1 are formed into spherical surfaces.
Even if deformation or curvature occurs due to thermal strain, airtightness between the two parts can be maintained. Furthermore, a compression spring 14 is provided inside the support tube 8 on the inflow side and is cooled by being exposed to the heated fluid supplied from the supply port 3. As shown in FIG. 5, this support tube 8 has a metal outer tube 8a welded around a through hole 10 in the wall surface 2, and slides in the axial direction while being in close contact with the inner peripheral surface of this outer tube 8a. The compression spring 14 is provided inside the outer tube 8a with its rear end supported on the wall surface 2 and its front end abutted against the inner tube 8b.
b is pushed out by this compression spring 14, and its convex spherical tip is brought into pressure contact with the concave spherical end face of the wall structure 7. Further, the support tube 9 on the outside of the other wall structure 7' has a retaining flange 9' at its rear part and supports the wall structure 7' immovably, and the ceramic tube 5 The elastic force of the compression spring 14 causes the wall surface 2,
2', and expansion and contraction in the axial direction are absorbed by the compression spring 14, and the ceramic tube 5 is connected to the support tubes 8, 9 of the wall structures 7, 7' and the wall surface. The ceramic tube 5 is connected to the fluid inflow chamber 3' and the fluid outflow chamber 4' through the through holes 10, 10' of
It forms a flow path for the fluid to be heated that flows through the inside of the tube. As mentioned above, when all the ceramic tubes 5 are installed between the wall surfaces 2 and 2', the outer surfaces of the wall structures 7 and 7' are in close contact with each other and the frame 1 is
Airtight walls 7a and 7a' are formed on both sides of the frame 1, thereby preventing heat transfer fluid such as high temperature exhaust gas flowing inside the frame 1 from leaking to the outside. Fixed walls 16 and 17 are formed on the front and rear, left and right inner surfaces of the frame 1, and correspond to the outer shape of the wall structures 7 and 7', and act as heat insulating walls for the support tubes 8 and 9, respectively. There is. The outer shape of the wall structure 7 is preferably a hexagonal prism so that the mutual adhesion is good and the ceramic tubes 5 are arranged in a dense triangular array, but the shape is not limited to this. In addition, a sealing material made of ceramic powder is provided on the outer circumferential surface of the wall structures 7, 7' as necessary.
and 7', 7', and furthermore, the ceramic tube 5 and the wall structure 7,
An elongated fluid divider 18 made of ceramics, which has an appropriate number of partition walls 21 radially stretched on the outer surface of a thin tube portion 20 having a central hole 19, is inserted into the inside of the ceramic tube 7', and flows inside the ceramic tube 5. The heat exchange efficiency is further improved by finely dividing the air flow to increase the film heat transfer coefficient within the ceramic tube and by mixing the fluid between the divided fluids 18, 18. In the embodiment described above, the compression spring 14 was disposed only between the support pipe 8 on the inflow side and the wall surface 2, but as in another embodiment shown in FIG. A compression spring 14 may also be disposed between .

This structure allows high-temperature exhaust gas discharged from various industrial furnaces to flow through the heat transfer fluid channel inside the frame 1, and also to flow through the through holes 10, 10' in the opposing wall surfaces 2, 2'. If room-temperature air is sent from the supply port 3 through the support tubes 8 to a large number of ceramic tubes 5 that are equipped with support tubes 8 and 9 at both ends, high-temperature air will flow through the walls of these ceramic tubes 5. Heat exchange between exhaust gas and air is similar to conventional heat exchangers of this type, but in the present invention, ceramic tubes 5 with excellent heat resistance and corrosion resistance are used as heat transfer tubes. Therefore, it is possible to exchange heat with exhaust gas at a temperature of over 1000℃, and has far superior temperature efficiency compared to conventional heat exchangers that can only be used for exhaust gas at temperatures below 1000℃. In addition, it is possible to recover heat from corrosive gases, which was not possible with heat exchangers using metal heat transfer tubes. Furthermore, when such high-temperature exhaust gas is introduced into the frame 1, each ceramic tube 5
However, in the present invention, each ceramic tube 5 has both ends connected to a wall 7.
a, a slidable wall structure 7 that constitutes 7a',
7', each ceramic tube 5 is held under the elastic force of a compression spring 14 provided between at least each wall structure 7 and one wall surface 2, so that the thermal expansion and contraction of each ceramic tube 5 is caused by the wall structure 7, 7. ′ will not be absorbed by the mutual movement of the ceramic tube 5 and damage the ceramic tube 5, and each wall surface structure 7,
Even if the walls 7' are stacked on both sides of the frame 1 with their outer surfaces in close contact with each other and relative movement occurs due to thermal expansion as described above, the walls 7a,
Since 7a' constitutes an airtight wall surface, the heat transfer fluid such as high-temperature exhaust gas flowing inside the frame 1 is completely prevented from leaking to the outside, and heat loss can be prevented. The thermal influence on the compression springs 14 and the like located outside the walls 7a, 7a' is alleviated. Moreover, since the compression spring 14 is constantly cooled by being exposed to the flow of the heated fluid supplied from the supply port 3, even if it is used for a long time without a special cooling mechanism, the There is no deterioration, and the ceramic tube 5 is properly and closely held between the wall surfaces 2 and 2', allowing efficient heat exchange to continue.

(Effects of the Invention) As is clear from the above description, the present invention provides an improvement in heat recovery that cannot be performed with the conventional shell-and-tube type heat exchanger using metal heat transfer tubes. It is possible to efficiently recover heat from exhaust gases and corrosive gases that are hotter than °C, and the non-uniform thermal expansion and contraction that occurs in each ceramic tube can be avoided by slidingly stacking them on both sides of the frame. Since a wall is formed in the section and a compression spring is used to repel the ceramic tube from both sides, the ceramic tube can be individually absorbed by the sliding movement of the wall structure, thereby preventing the ceramic tube from being damaged. moreover,
This wall structure prevents the heat transfer fluid from leaking through the walls formed on both sides of the frame, and also provides compression springs provided between each wall structure forming the wall and the wall surface. Since the heated fluid supplied from the mouth is continuously cooled during heat exchange, the compression spring can be used for a long period of time, and there is no need to install a special cooling mechanism, resulting in low costs. It has various advantages such as this, and it will greatly contribute to the development of the industry as it solves the problems of conventional heat exchangers of this type.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention, FIG. 2 is a vertical side view, FIGS. 3 and 4 are partially cutaway front views showing an embodiment of a ceramic tube, and FIG. 6 is a partially cutaway front view of the main part, FIG. 6 is a partially cutaway perspective view of the wall structure, FIG. 7 is a perspective view of the fluid divider, and FIG. 8 is a partially cutaway diagram showing another embodiment of the present invention. This is a raw side view. 1: Frame body, 2, 2': Wall surface, 3: Supply port, 4:
Outlet, 5: Ceramics tube, 6: Fin, 7,
7': Wall structure, 7a, 7a': Wall, 10, 1
0': Through hole, 11, 11': Through hole, 14: Compression spring, 18: Fluid division, 19: Center hole, 21: Partition wall.

Claims (1)

[Scope of Claims] 1. Through holes 10, 10' communicating with the supply port 3 and outlet port 4 of the fluid to be heated are formed in the opposing wall surfaces 2, 2' of the frame body 1 whose interior is formed into a heat transfer fluid flow path. In a heat exchanger in which a large number of through holes 10 and 10' are connected to each other, holes 11 and 1 are provided on both sides of the frame body 1.
Walls 7a and 7a' are provided in which wall structures 7 and 7' with 1' are stacked up in a slidable manner. A plurality of ceramic tubes 5 each having a central hole 19 and a radial partition wall 20 and into which a ceramic divided fluid 18 is inserted are provided, and each ceramic tube 5 has a ceramic tube 5 on the inflow side of the fluid to be heated.
A heat exchanger characterized in that a compression spring 14 is provided in pressure contact with a ceramic tube to absorb expansion and contraction in the axial direction of the heat exchanger. 2. The heat exchanger according to claim 1, wherein the wall structures 7, 7' have a hexagonal column shape. 3. The heat exchanger according to claim 1 or 2, wherein the wall structures 7, 7' and the ceramic tube 5 are both made of silicon carbide. 4. Claim 1 in which the ceramic tube 5 is orthogonal to the heat transfer fluid path formed inside the frame body.
The heat exchanger according to item 1 or 2 or 3.