JP2012220154A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a refractory material from cracking by absorbing strain due to a temperature difference of a heat transfer tube.SOLUTION: On a circumference centering on an axis of a vertical high temperature path H, a plurality of metallic heat transfer tubes 13 for low temperature path formation which extend in parallel with the axis are lined up at intervals with adjacent tubes. A vertical cyclindrical refractory material-made inner wall 21 and a vertical cyclindrical refractory material-made outer wall 22 are provided on both sides of the array of the heat transfer tubes 13 mutually at intervals. A granular heating medium 24 is charged in peripheries of the respective heat transfer tubes 13 between the inner wall 21 and outer wall 22.

Description

  The present invention relates to the thermal energy of high-temperature combustion gas (exhaust gas) generated in the process of incineration of waste in municipal waste incinerators and industrial waste incinerators and in the process of melting ash discharged from the incinerators. The present invention relates to a heat exchanging device that is recovered by exchanging and that makes effective use of heat energy.

  As this type of heat exchange device, the cylindrical wall for forming a high-temperature passage is composed of a refractory inner wall and an outer wall made of heat insulating material surrounding the outer surface of the outer wall via an air layer. It is known that a metal heat transfer tube for forming a low-temperature passage is extended (see, for example, Patent Document 1).

  In such a structure, there is no problem of the difference in thermal expansion between the refractory material and the heat transfer tube that occurs during heat exchange, but there is an air layer between the refractory material and the heat transfer tube, resulting in poor heat transfer efficiency. There is.

  Further, as another heat exchange device, the high-temperature passage forming cylindrical wall body is formed by a double wall structure including an inner wall made of a refractory material and an outer wall made of a heat insulating material, both on the inner wall outer surface and the outer wall inner surface, It is known that notches are formed to be opposed to each other, and a metal heat transfer tube for forming a low-temperature passage extending in the axial direction of the inner wall is passed through a space formed by the combination of both notches ( For example, see Patent Document 2.)

  In such a structure, based on the temperature difference between the inner wall and the outer wall, a temperature difference is generated between the inner surface side and the outer surface side of the heat transfer tube, which causes distortion in the heat transfer tube. As a result, there is a problem that the refractory material breaks without being able to absorb this strain, and high temperature gas (exhaust gas) enters from the cracks of the refractory material and corrodes the heat transfer tube.

JP 2001-41681 A JP-A-10-325527

  An object of the present invention is to provide a heat exchange device that can absorb deformation due to thermal expansion of a heat transfer tube.

  In the heat exchange device according to the present invention, a plurality of metal heat transfer tubes for forming a low temperature passage extending parallel to the coaxial line are spaced apart from each other on a circumference centering on the axis of the vertical high temperature passage. It is arranged in a row, and a vertical cylindrical refractory inner wall and a vertical cylindrical heat insulating outer wall are provided on both sides of the same heat transfer tube row, spaced from each other, and each between the inner wall and the outer wall The heat transfer tube is filled with a particulate heat medium.

  In the heat exchange device according to the present invention, the deformation due to the thermal expansion of the heat transfer tube is not restricted by the refractory material on the inner wall, and the deformation can be absorbed by the heat medium.

  Furthermore, the heat medium is a spherical ceramic, and the particle diameter of the ceramic is preferably 0.125 to 3 mm.

  The ceramic is preferably, for example, alumina oxide or silicon carbide, which is very hard, has excellent wear resistance, and can be used in a high temperature atmosphere.

  The heat medium may be spherical silica sand, and the particle diameter of the silica sand may be 0.3 to 0.6 mm.

  According to this invention, it becomes possible to absorb the deformation | transformation of a heat exchanger tube, without the deformation | transformation by thermal expansion of a heat exchanger tube being restrained by a refractory material.

It is a perspective view containing the crushing cross section of the heat exchange apparatus by this invention. It is a horizontal cross-sectional view of the same heat exchange device.

  Referring to FIG. 1, the heat exchanging device includes a vertical cylindrical wall body 11 in which a high temperature gas H flows inside, a metal vertical cylindrical casing 12 coated on the outer surface of the wall body 11, and a circumference of the wall body 11. It consists of a plurality of metal vertical heat transfer tubes 13 that are penetrated through the wall 11 so as to be arranged at equal intervals in the direction and into which the low temperature gas L flows.

  The wall body 11 has a double wall structure, and is provided with a refractory material inner wall 21 for protecting the heat transfer tube 13 from the corrosive components of the hot gas H, and for passing the heat transfer tube 13 to the inner wall 21. The outer wall 22 is made of a heat insulating material opposed to the space 23, and the spherical ceramic heat medium 24 filled around the heat transfer tube 13 in the space 23.

  An annular exhaust header 31 surrounds the upper end portion of the outer surface of the casing 12, and an annular air supply header 32 surrounds the lower end portion thereof. End portions corresponding to the upper and lower sides of the heat transfer tubes 13 are communicated with the exhaust header 31 and the air supply header 32.

  As shown in FIG. 2, a plurality of metal anchors 41 are fixed to the inner surface of the casing 12 in the circumferential direction of the casing 12 at the same intervals as the intervals of the heat transfer tubes 13. The anchor 41 has a Y-shape, and extends straight inward in the radial direction from the inner surface of the casing 12 and is passed through the heat medium between two adjacent heat transfer tubes 13, and the straight portion 41a It comprises a bifurcated portion 41b provided integrally with the inner end and embedded in the inner wall 21.

  The hot gas H generated by burning the waste is passed through the inner wall 21. The low temperature gas L is passed through the heat transfer tube 13 and absorbs the heat of the high temperature gas H to exchange heat. A temperature difference occurs between the inner surface side and the outer surface side of the heat transfer tube 13, and therefore, the heat transfer tube 13 is distorted.

  Since the heat transfer tube 13 is filled with the heat medium 24, even if the heat transfer tube is deformed by the thermal expansion of the heat transfer tube, the deformation is absorbed by the heat medium, thereby preventing cracking of the refractory material. .

  The manufacturing procedure of the heat exchanger will be described below.

a) The casing 12, the heat transfer tube 13, the exhaust header 31, and the air supply header 32 are respectively set at predetermined positions.

b) A heat insulating material to be the outer wall 22 is attached to the inner surface of the casing 12.

c) Set the inner formwork made of wire mesh where it should be the inner surface of the outer wall 22.

d) Set the anchor 41 in place.

e) Set the wooden formwork outside the outer wall 22 where it should be.

f) Pour a refractory material to be the outer wall 22 between the inner mold and the outer mold, and cure for a predetermined period. After this, the inner mold is left buried in the refractory material, but the outer mold is removed from the refractory material.

g) Fill heat medium between insulation and refractory.

h) Dry fire to sinter the refractory material.

  The heat exchanging device according to the present invention is suitable for achieving the ability to absorb the distortion due to the temperature difference of the heat transfer tubes and prevent the refractory material from cracking.

13 Heat transfer tube
21 inner wall
22 Exterior wall
24 Heat medium

Claims (3)

  A plurality of metal heat transfer tubes for forming a low-temperature passage extending in parallel with the coaxial line are arranged in a line at intervals between adjacent members on a circumference centered on the axis of the vertical high-temperature passage. A vertical cylindrical refractory inner wall and a vertical cylindrical heat insulating outer wall are provided on both sides of the heat transfer tube array so as to be spaced apart from each other, and the particulate heat is formed around each heat transfer tube between the inner wall and the outer wall. A heat exchange device filled with a medium.   The heat exchange device according to claim 1, wherein the heat medium is ceramic.   The heat exchange device according to claim 1, wherein the heat medium is silica sand.

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