JP2001221586A - Heat exchanging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanging device that can stably maintain the flowing time of a heating medium in a heat exchanging chamber, especially the upper part of the heat exchanging chamber in which high-temperature gas circulates. SOLUTION: The cross section of each of heat exchanging chambers 2 and 4 is made to have a rectangular shape, and each of trays 6 and 7 of these heat exchanging chambers 2 and 4 is made to be a titled tray without hole parts. The vertically adjacent trays 6 and 7 are bulged in horizontally opposite directions to each other. In the horizontally projected section of each of the trays 6 and 7, the cross section of the heat exchanging chambers 2 and 4 are covered widthwise, and an open part 24 is formed in the tip side lengthwise. The passage of gases 1 and 3 at the location of each of the trays 6 and 7 is limited to the open part 24, and the flow velocity of the gases 1 and 3 passing through the open part 24 is set to be approximately equal to the equilibrium velocity of free fall of a heating medium in the gases 1 and 3. Thereby, the flowing time of the heating medium 8 at the time when it falls through this open part 24 is secured long, and heat exchanges between the heating medium 8 and each of the gases 1 and 3 can be performed sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for recovering sensible heat of a high-temperature gas into a low-temperature gas by using a granular heat medium.

[0002]

2. Description of the Related Art An example of a heat exchange apparatus for recovering sensible heat from a high-temperature gas such as exhaust gas using a granular heat medium having a diameter of about 1 to 3 mm and heating a low-temperature gas such as normal-temperature air with the recovered sensible heat. Japanese Patent Application No. 2000 filed by the applicant of the present invention
No. 16859.

As shown in FIG. 6, the heat exchange device includes an upper heat exchange chamber 52 through which a high-temperature gas 51 flows, and a low-temperature gas 5.
The lower heat exchange chambers 54 through which the heat exchanger 3 flows are arranged vertically, and these heat exchange chambers 52 and 54 are communicated with each other through a communication section 55 having a small cross section. 57 are provided in a plurality of stages.

[0004] Each tray 56 of the upper heat exchange chamber 52 includes:
Upper and lower adjacent trays 56 are attached so as to project obliquely downward and obliquely in opposite directions to each other, and an opening is formed at the tip end side. Further, each tray 57 of the lower heat exchange chamber 54 is horizontally mounted so as to cover the cross section of the lower heat exchange chamber 54. A vibration device 58 is also attached to each tray 56, 57.

[0005] The granular heat medium 59 is introduced from an introduction port 60 provided in the upper heat exchange chamber 52, and absorbs the heat of the high-temperature gas 51 while falling down each tray 56 in order. The heat medium 59 that has absorbed the heat is collected at the center of the cone-shaped bottom of the upper heat exchange chamber 52, and moves to the lower heat exchange chamber 54 while keeping the small-section communicating portion 55 in a filled state.

The heat medium 59 moved to the lower heat exchange chamber 54
The high-temperature gas 51
The sensible heat absorbed from the gas is released to the low-temperature gas 53. The heat medium 59 that has released the sensible heat is collected at the center of the cone-shaped bottom of the lower heat exchange chamber 54, discharged from the discharge port 61 to the ejector 62, returned to the hopper 64 through the transfer pipe 63, and returned to the input port 60. From the upper heat exchange chamber 52 again.

In this heat exchange apparatus, a perforated plate is used for each of the trays 56 and 57, so that the heat medium 59 flows on each of the trays 56 and 57 with a gas blown up from the hole of the perforated plate, and the contact time with the gas is reduced. Is made longer so that heat exchange can be sufficiently performed. Further, by inclining each tray 56 of the upper heat exchange chamber 52, the heat medium 59 adhered to the tray 56 by the adhesive substance in the high-temperature gas 51 is separated from the tray 56 by the vibration device 58, and these heat medium 59 is dropped onto the lower tray 56 along the inclined surface so that the heat medium 59 can be circulated smoothly.

[0008]

The above-mentioned conventional heat exchanger uses a perforated plate for the tray of each heat exchange chamber to allow the heat medium to flow on the tray, and the contact time with the gas for heat exchange. However, since the heat medium also falls from the holes in the perforated plate tray, the flow rate of the gas blown up from the holes, that is, the amount of gas supplied to each heat exchange chamber, makes it possible to secure the heat medium on the tray. However, there is a problem that the flow time of the heat medium greatly changes. If the supply amount of the gas is small, the heat medium drops immediately from the hole, and if the supply amount of the gas is too large, the heat medium remains in a flowing state for a long time, and it is difficult to drop.

In the upper heat exchange chamber, exhaust gas from an incinerator or cracked gas generated in a melting furnace or a pyrolysis furnace is often used as a high-temperature gas to be circulated.
Lumps of dust such as fly ash contained in the exhaust gas and the decomposition gas may be placed on the tray and block the holes of the perforated plate. Therefore, there is a problem that the flow velocity of the gas blown up from the hole changes, the pressure loss in the heat exchange chamber increases, and the air volume of the gas flowing through the heat exchange chamber decreases. Exhaust gas and cracked gas contain adhering fly ash and chloride, so these adhering substances adhere to the holes and narrow the cross-sectional area, changing the flow velocity of the gas blown up from the holes And the pressure loss in the heat exchange chamber is increased.

Although the above-mentioned problems do not occur if a flat inclined tray having no holes is used, the use of a simple flat inclined tray causes the heat medium to immediately roll off the inclined surface, so that the heat is lost. The contact time between the medium and the gas is short, and the heat exchange efficiency deteriorates.

It is an object of the present invention to provide a heat exchange apparatus which can stably maintain a flow time of a heat medium in a heat exchange chamber, particularly an upper heat exchange chamber through which a high-temperature gas flows.

[0012]

In order to solve the above-mentioned problems, the present invention is directed to an upper heat exchange chamber in which a high-temperature gas flows from below to above, and a lower heat exchange chamber in which a low-temperature gas flows from below to above. Are provided above and below, the lower part of the upper heat exchange chamber and the upper part of the lower heat exchange chamber communicate with each other through a communication section having a small cross section, and trays are provided in a plurality of stages vertically in each heat exchange chamber. The heat medium supplied from the input port of the heat medium provided in each tray of the upper heat exchange chamber, the communication portion, each tray of the lower heat exchange chamber, sequentially dropped to the bottom of the lower heat exchange chamber, In the heat exchange device for exchanging heat with the gas flowing through each of the heat exchange chambers, at least the upper heat exchange chamber has a rectangular cross section, and each tray of the heat exchange chamber having the rectangular cross section has an upper surface. Are vertically adjacent to each other as an inclined tray The oblique trays are projected in opposite directions to each other, and the horizontal projection cross-sections of these oblique trays are rectangular, and cover the rectangular cross-section of the heat exchange chamber in the width direction, and open in the longitudinal direction at the tip side of the oblique tray. Part is formed, and the flow velocity of the gas passing upward from below through the opening formed at the tip side of each of these inclined trays is substantially equal to the equilibrium velocity of free fall of the heat medium in the gas. A configuration for setting equality was adopted.

That is, at least the upper heat exchange chamber has a rectangular cross section, and each tray of the heat exchange chamber is an inclined tray having no hole, and vertically adjacent trays are projected in opposite directions to each other. The horizontal projection section covers the cross section of the heat exchange chamber in the width direction, and an opening is formed on the tip side in the longitudinal direction, and a gas passage at each tray portion is formed on the tip side of the tray. By restricting the flow velocity of the gas passing through the opening to the opening, the flow speed of the heating medium when falling through the opening is set by setting the flow velocity of the gas passing through the opening to be substantially equal to the equilibrium velocity of the free fall in the gas. A long time was secured so that heat exchange with the gas could be sufficiently performed.

The equilibrium velocity Vt (m / sec) of the free fall of the heat medium in the gas can be calculated from the following equation of motion of the particles depending on the Reynolds number Re by considering the heat medium as spherical particles. You can ask.

[0015] Vt when Re ≦ 2 = (ρs -ρf) g · D 2 / 18μ (1) 2 <Vt when Re ≦ 500 = {4 (ρs -ρf) 2 g 2 / 225μ · ρf} 1 / here ^{3 D (2) Re> 500} Vt when = {3 (ρs -ρf) g · D / ρf} 1/2 (3), g: gravitational acceleration ^{(9.8m / sec 2), D} : Heat medium diameter (m), ρs: density of heat medium (kg / m ³ ), ρf
: Gas density (kg / m ³ ), μ: Gas viscosity (kg / m · s)
ec).

Although the equilibrium speed Vt slightly varies depending on the diameter of the heat medium, as described above, the diameter of the heat medium is 1 to 3 mm.
Therefore, if the equilibrium speed Vt is set according to the average diameter of the heat medium to be used, the flow time of the majority of the heat medium can be secured long. The difference in the equilibrium speed Vt due to the change in the density of the gas or heat medium due to the temperature change is very small.

The lower surface of each of the inclined trays is formed so as to be inclined upward at the same angle as the upper surface of the inclined tray toward the front end, and the lower surface of the upper inclined tray and the upper surface of the lower tray adjacent to each other are formed. To form an inclined passage with a parallel cross section between
By setting the flow velocity of the gas passing through the inclined passage to approximately half the equilibrium velocity of the free fall of the heat medium,
Also in the inclined passage between the trays, the flow time of the heat medium can be lengthened.

By providing a vibration means for vibrating each of the inclined trays, it is possible to prevent the heat medium from adhering to the trays,
The heat medium can be circulated smoothly.

Each of the inclined trays has a hollow structure, and the upper and lower surfaces of the inclined trays are formed of a plate material having a thickness of 4 mm or less, thereby reducing the inertia of the inclined trays. Can be vibrated.

By providing a weir extending on the upper surface of each of the inclined trays in a direction substantially perpendicular to the inclination direction of the upper surface, the heat medium that rolls down the upper surface of the inclined tray is dammed by the weir, and the heat medium falling on the tray is blocked. A portion of the medium can be made to impinge on these damped heat media, reducing wear on the upper surface of the inclined tray and extending its life. Further, there is also an effect that the heat medium rolling down the inclined surface hits the dam and repels, so that the contact time between the heat medium and the gas becomes longer.

Each of the inclined trays is attached to the casing of the heat exchange chamber so as to be movable forward and backward, and the cross-sectional area of an opening formed at the tip end of each of the inclined trays is adjustable. The flow rate of the gas passing through can be easily adjusted.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 and FIG.
FIG. As shown in FIG. 1, the heat exchange device includes an upper heat exchange chamber 2 through which a high-temperature gas 1 of flue gas flows.
And lower heat exchange chambers 4 through which the low-temperature gas 3 flows are arranged vertically, and these heat exchange chambers 2 and 4 are communicated by a communication pipe (communication portion) 5, and a tray is provided to each of the heat exchange chambers 2 and 4. 6, 7
Are provided in a plurality of stages.

The granular heat medium 8 is introduced from an inlet 9 provided in the upper part of the upper heat exchange chamber 2, and each tray 6 of the upper heat exchange chamber 2, the communication pipe 5, and each tray of the lower heat exchange chamber 4 are provided. 7,
It falls to the bottom of the lower heat exchange chamber 4 in order, recovers sensible heat by contacting the upper heat exchange chamber 2 with the hot gas 1 flowing from the vent 10 to the exhaust port 11, and vents the lower heat exchange chamber 4. The sensible heat collected by the low-temperature gas 3 flowing from the port 12 to the exhaust port 13 is released to heat the low-temperature gas 3.

The heat medium 8 that has fallen to the bottom of the lower heat exchange chamber 4 is discharged to an ejector 15 from a discharge port 14 provided at the bottom, and is transported by air blown from a blower 16 to a transfer pipe 17.
And is returned to the upper heat exchange chamber 2 through the inlet 9 again. In addition, below the exhaust port 11 provided at the ceiling of the upper heat exchange chamber 2, a disc-shaped scattering prevention plate 19 for preventing the heat medium 8 from scattering outside is attached. The heat medium 8 inside the communication pipe 5
In order to maintain the state of filling, a fin-shaped flow rate adjusting plate 20 for adjusting the amount of the heat medium 8 falling from the communication pipe 5 is attached.

As shown in FIGS. 2A and 2B, the casing of each of the heat exchange chambers 2 and 4 is formed by lining a refractory 22 on a steel shell 21 and has a rectangular cross section. I have. Each of the trays 6 and 7 is formed of a rectangular plate that covers this rectangular cross section in the width direction, and is inserted with its tip obliquely downward from a tray mounting port 23 provided on the side wall of each of the heat exchange chambers 2 and 4. An opening 24 through which the gases 1 and 3 pass is formed at the tip side. The tray mounting ports 23 are provided on the side walls of the heat exchange chambers 2 and 4 facing each other in a staggered manner, and the vertically adjacent trays 6 and 7 are mounted with their tips facing left and right in opposite directions.

A flange 25 is provided at the base end of each of the trays 6 and 7, and the flange 25 is attached to the flange 27 of the tray mounting opening 23 via a spacer 26. By changing the thickness of the spacer 26, The overhang amount of each tray 6 and 7 can be changed, and the cross-sectional area of the opening 24 can be adjusted. A hammer-type vibrating device 28 is pressed against the flange 25 of each of the trays 6 and 7.

The cross-sectional area of the opening 24 is adjusted so that the flow velocity Vg of each of the gases 1 and 3 rising therethrough is substantially equal to the equilibrium velocity Vt of the free fall of the heat medium 8 in each of the gases 1 and 3. Have been.

In this embodiment, the average diameter D of the heat medium 8 is
Is 1.2 mm (0.0012 m) and density ρs is 3650
kg / m ³ , and the density ρf of each gas 1 and 3 is 0.568 kg / m
^{3. The} viscosity μ is 0.000031 kg / m · sec, the Reynolds number Re is 287, and the equilibrium speed Vt calculated from the equation (2) is about 13 m / sec. Therefore, the cross-sectional area of the opening 24 was adjusted so that the flow velocity Vg of each of the gases 1 and 3 was 13 m / sec. Since the equilibrium speed Vt slightly changes depending on the diameter D of the heat medium 8, the ratio of the flow velocity Vg to the actual equilibrium speed Vt is Vg / Vt = 0.8 to 1.25.
Is in the range. Therefore, the heat medium 8 that falls from each opening 24 onto each of the lower trays 6 and 7 is
With the gases 1 and 3 rising at a flow velocity Vg substantially equal to the equilibrium velocity Vt, the vertical movement is repeated near the cross section of the opening 24, and the contact time with each gas 1 and 3 is extended.

FIGS. 3 and 4 show a second embodiment. This heat exchange device comprises upper and lower heat exchange chambers 29, 30.
Only the form and mounting method of each tray 31 and 32 are the first
Different from the first embodiment, the cross-sectional dimensions and shapes of the heat exchange chambers 29 and 30, the heat medium 8 to be used, and other peripheral configurations are the same as those of the first embodiment. Therefore, these same parts are denoted by the same reference numerals as in the first embodiment.

As shown in FIGS. 4A and 4B, the trays 31 and 32 of each of the heat exchange chambers 29 and 30 have a thickness of 2.6 mm.
A hollow structure is formed by using the steel plate described above, and its upper and lower surfaces are inclined in opposite directions toward each other at an equal angle toward the distal end, and are formed to have a thin distal end. Each of the trays 31 and 32 covers the rectangular cross section of each of the heat exchange chambers 29 and 30 in the width direction, similarly to the first embodiment, and an opening 33 through which each of the gases 1 and 3 passes is provided at the front end thereof. Is formed. The opening 33 has the same cross-sectional area as the opening 24 of the first embodiment, and the flow velocity Vg of each of the gases 1 and 3 rising through the opening 33 is also set to 13 m / sec.

Each of the trays 31 and 32 is connected to each of the heat exchange chambers 29 and
The trays 31 and 32 which are horizontally inserted from the tray mounting port 34 provided on the side wall of the upper side 30 and which are vertically adjacent to each other are mounted with their leading ends left and right opposite to each other. Lower and lower trays 31,
An inclined passage 35 having a parallel cross section is formed between the upper surface of the passage 32 and the upper surface of the passage 32. The cross-sectional area of this inclined passage 35 is
Each of the gases 1 and 3 passing through the inclined passage 35 rises obliquely at approximately half the flow velocity Vg of each of the gases 1 and 3 rising through the opening 33.

On the upper surface of each of the trays 31, 32, a weir member 3 made of a half-split pipe extending in a direction orthogonal to the inclination direction thereof.
6 are attached in parallel. Each tray 31,
Since the heat medium 8 rolling down the inclined upper surface of 32 is dammed by each dam member 36, a part of the heat medium 8 falling on the tray collides with the damped heat medium 8,
Wear on the upper surfaces of the trays 31 and 32 is reduced. Further, the heat medium 8 that rolls down the inclined surface hits the dam member 36 and repels, so that there is an effect that the contact time between the heat medium 8 and each of the gases 1 and 3 becomes longer. An angle material, a strip material, or the like may be used for the weir member 36.

The base end of each of the trays 31 and 32 has a refractory 3
7 is closed by a lid member 38 lined with
8 is attached to the flange 39 of the tray attachment port 34. A hammer type vibration device 40 is also attached to the lid member 38, and a hammer rod 41 of the vibration device 40 is inserted in a horizontal direction from a hole provided in a central portion of the lid member 38, and the inside of each of the trays 31 and 32. It is pressed against the beam 42.

Each of the trays 31 and 32 is
When the hammer is hammered in the horizontal direction, as shown in FIG. 5, a horizontal impact force F is applied to the heat medium 8 attached to the upper surfaces of the trays 31 and 32.
There acts, by the component force F _B of the tray upper surface and the direction perpendicular to the horizontal impact force F, the heat medium 8 attached to the upper tray surface is peeled off. Therefore, the heat medium 8 can be smoothly circulated in the apparatus. At the same time, the horizontal impact force F also acts on the dust and the like attached to the lower surfaces of the trays 31 and 32, and the dust and the like are separated by the component force of the horizontal impact force F in the direction orthogonal to the lower surface of the tray. Adhesion and deposition of dust and the like on the lower surface of the nozzle 32 can also be prevented.

In each of the above-described embodiments, the upper and lower heat exchange chambers have rectangular cross sections, and each of the heat exchange chambers has an inclined tray having no hole, and the gas passage at each tray is inclined. It is limited to the opening formed on the tip side of the tray, and the flow velocity of the gas passing through this opening is set to be approximately equal to the equilibrium speed of free fall in the heat medium gas. It may be adopted only in the upper heat exchange chamber in circulation.

[0036]

As described above, according to the heat exchange apparatus of the present invention, at least the upper heat exchange chamber through which the high-temperature gas flows has a rectangular cross section, and each of the trays in this heat exchange chamber is formed as an inclined tray having no holes. As the upper and lower adjacent trays project in opposite directions to each other, the horizontal projection section of each tray covers the cross section of the heat exchange chamber in the width direction, and an opening is formed on the tip side in the longitudinal direction, The gas flow path at each tray is limited to the opening formed at the tip of the tray, and the flow velocity of the gas passing through the opening is set to be approximately equal to the equilibrium velocity of the free fall in the heat medium gas. Therefore, it is possible to secure a long flow time of the heat medium when dropping through the opening, and to sufficiently perform heat exchange between the heat medium and the gas.

The lower surface of each inclined tray is formed to be inclined upward at the same angle as the upper surface of the inclined tray toward the front end, so that the lower surface of the upper inclined tray and the upper surface of the lower tray adjacent to each other are formed. To form an inclined passage with a parallel cross section between
By setting the flow velocity of the gas passing through the inclined passage to be approximately half of the equilibrium velocity of the free fall of the heat medium, the flow time of the heat medium is also increased in the inclined passage between the trays, and the heat exchange efficiency is further improved. Can be enhanced.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing a heat exchange device according to a first embodiment.

FIG. 2A is a longitudinal sectional view showing an enlarged main part of FIG. 1, and FIG. 2B is a sectional view taken along line II-II of FIG.

FIG. 3 is a schematic longitudinal sectional view showing a heat exchange device according to a second embodiment.

4A is a longitudinal sectional view showing an enlarged main part of FIG. 3, and FIG. 4B is a sectional view taken along line IV-IV of FIG.

FIG. 5 is an enlarged sectional view showing a horizontal impact force acting on the upper surface of the tray of FIG. 3;

FIG. 6 is a schematic longitudinal sectional view showing a conventional heat exchange device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High temperature gas 2 Heat exchange room 3 Low temperature gas 4 Heat exchange room 5 Communication pipe 6, 7 Tray 8 Heat medium 9 Input port 10 Vent port 11 Exhaust port 12 Vent port 13 Exhaust port 14 Discharge port 15 Ejector 16 Blower 17 Transport pipe 18 Hopper 19 Anti-scattering plate 20 Flow control plate 21 Steel 22 Refractory 23 Tray mounting opening 24 Opening 25 Flange 26 Spacer 27 Flange 28 Vibration device 29, 30 Heat exchange chamber 31, 32 Tray 33 Opening 34 Tray mounting opening 35 Inclined Passageway 36 Weir member 37 Refractory 38 Lid member 39 Flange 40 Vibration device 41 Hammer bar 42 Inner beam

Claims (6)

[Claims] 1. An upper heat exchange chamber in which a high-temperature gas flows from below to above and a lower heat exchange chamber in which a low-temperature gas flows from below to above are provided up and down. The upper portion of the chamber is communicated with a communication section of a small cross section, trays are provided in a plurality of stages vertically in each heat exchange chamber, and a heat medium supplied from an inlet of a heat medium provided in the upper heat exchange chamber, Each tray of the upper heat exchange chamber, the communication section, each tray of the lower heat exchange chamber, sequentially dropped to the bottom of the lower heat exchange chamber,
In the heat exchange device for exchanging heat with the gas flowing through each of the heat exchange chambers, at least the upper heat exchange chamber has a rectangular cross section, and each tray of the heat exchange chamber having the rectangular cross section has an upper surface. As an inclined tray descending to the tip side,
The inclined trays vertically adjacent to each other are extended in the opposite directions to each other, and the horizontal projection cross-sections of these inclined trays are rectangular, and cover the rectangular cross-section of the heat exchange chamber in the width direction, and of the inclined tray in the longitudinal direction. An opening is formed on the tip side, and the flow rate of the gas passing from the bottom to the top through the opening formed on the tip side of each of these inclined trays is controlled by the free fall of the heat medium in the gas. A heat exchange device characterized by being set to be approximately equal to an equilibrium speed. 2. The lower surface of each of the inclined trays is formed so as to be inclined upward at the same angle as the upper surface of the inclined tray toward the distal end, so that the lower surface of the upper inclined tray and the lower tray adjacent to each other are formed. 2. An inclined passage having a parallel cross section with the upper surface, and a flow velocity of the gas passing through the inclined passage is set to approximately half of an equilibrium velocity of the free fall of the heat medium.
The heat exchange device according to item 1. 3. The heat exchange device according to claim 1, further comprising a vibration unit that vibrates each of the inclined trays. 4. The heat exchange apparatus according to claim 3, wherein each of the inclined trays has a hollow structure, and upper and lower surfaces of the inclined trays are formed of a plate having a thickness of 4 mm or less. 5. The heat exchange device according to claim 1, wherein a weir is provided on an upper surface of each of the inclined trays, the weir extending in a direction substantially orthogonal to an inclination direction of the upper surface. 6. The inclined trays are attached to a casing of the heat exchange chamber so as to be adjustable back and forth, and a cross-sectional area of an opening formed at a tip side of each inclined tray is adjustable. 6. The heat exchange device according to any one of 5.