JP3841690B2 - Heat exchanger - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat exchange device that circulates and uses a granular heat medium to recover sensible heat of a high-temperature gas into a low-temperature gas, and particularly relates to a device that uses high-temperature exhaust gas as a high-temperature gas.
[0002]
[Prior art]
In a heat exchange device that circulates and uses a granular heat medium and recovers sensible heat from a high-temperature gas, there is a problem that deposits such as dust accumulate on the heat medium being circulated and lower the heat exchange efficiency.
[0003]
As a means for removing such deposits of the heat medium, there is a method of providing a cleaning device in the return path for circulating the heat medium (Japanese Patent Laid-Open No. 50-92548), or a vibrating sieve equipped with a screen in the return path. A method of providing it (Japanese Patent Laid-Open No. 57-120002) has been proposed.
[0004]
On the other hand, in a heat medium circulation type heat exchange device that uses high-temperature exhaust gas discharged from a melting furnace or the like as the high-temperature gas and recovers sensible heat of this high-temperature exhaust gas to a low-temperature gas, the gaseous metal contained in the high-temperature exhaust gas Chloride is liquefied due to a decrease in temperature due to heat exchange, becomes sticky, and adheres to the surface of the heat medium as a deposit. Since metal chloride deposits are very sticky, they cause the heat medium to adhere to the inner surface of the heat exchange device or cause the heat media to coagulate with each other. For this reason, this metal chloride deposit not only lowers the heat exchange efficiency like the above-mentioned deposits such as dust, but also has a problem of blocking a narrow passage in the heat exchange device.
[0005]
[Problems to be solved by the invention]
Among the means for removing deposits described above, the method of providing a heating medium cleaning device in the return path can considerably remove even deposits of highly viscous metal chloride, but cleaning with water is mainly used. Since the removing means is used, the cleaning time becomes long, and there is a problem that the heat loss due to the temperature drop of the heat medium becomes very large. In Japanese Patent Laid-Open No. 50-92548, hot water is used as the washing water. However, the higher the temperature of the washing water, the greater the heat energy required for the washing water. Moreover, in order to wash | clean all the heat media to circulate, a washing | cleaning apparatus is also large sized.
[0006]
On the other hand, the method of providing a vibrating screen in the return path can remove deposits such as dust, but cannot remove deposits of highly viscous metal chloride.
[0007]
Accordingly, an object of the present invention is to efficiently remove adhesive deposits adhering to the heat medium of a heat exchange device that uses high-temperature exhaust gas for sensible heat recovery without causing a large heat loss.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention passes a granular heat medium from an upper heat exchange chamber in which high-temperature exhaust gas flows to a lower heat exchange chamber in which low-temperature gas flows, so that each of these heat exchange chambers is passed through. In a heat exchange device that exchanges heat with the circulating gas and circulates the heat exchanged granular heat medium from the lower heat exchange chamber to the upper heat exchange chamber via a return path, the heat media are placed in a container in the return path. A configuration was adopted in which a means for rubbing inside was provided to remove deposits adhering to the surface of the heat medium.
[0009]
In other words, by providing a means for rubbing the heat mediums in the container in the return path for circulating the heat medium, the heat medium aggregated with the sticky metal chloride deposits is crushed. And the heat medium were rubbed together to remove the sticky deposit from the surface of the heat medium so that the sticky deposit on the heat medium could be efficiently removed without causing heat loss.
[0010]
By providing a water supply port and a drain port for the washing water in the container that rubs the heat mediums together, the deposits separated from the heating medium are discharged out of the container together with the washing water, and the peeled adhesive deposits are again formed. It can be prevented from adhering to the heat medium, and its removal efficiency can be further increased.
[0011]
A secondary return path that branches into the return path may be provided, and a means for rubbing the heat mediums in the container may be provided on the secondary return path side. Adhesive deposits gradually accumulate while the heat medium repeats circulation, and it is not always necessary to remove all the heat medium deposits for each circulation, so a secondary return path that branches in this way is provided. The adhesive deposit may be removed from only a part of the heat medium on the auxiliary return path side.
[0012]
In addition, the present invention allows a granular heat medium to pass from the upper heat exchange chamber in which the high-temperature exhaust gas flows to the lower heat exchange chamber in which the low-temperature gas flows to exchange heat with the gas flowing through each of these heat exchange chambers. In the heat exchange device for circulating the heat-exchanged granular heat medium from the lower heat exchange chamber to the upper heat exchange chamber through a return path, a sub-return path branching to the return path is provided, and the sub-return path includes the sub-return path. A configuration provided with a heat medium cleaning means was also employed.
[0013]
As described above, it is not always necessary to remove the deposits of the heat medium every time it is circulated. Therefore, by providing a heat medium cleaning means in the auxiliary return path branched from the return path, this auxiliary return path is provided. Thus, the sticky deposit on only a part of the heat medium can be removed, and the sticky deposit on the heat medium can be sequentially removed without causing a significant heat loss. Further, the cleaning means for the auxiliary return path only needs to process a part of the heat medium, so that it can be made small.
[0014]
A sieving means for the heat medium is provided at a branch point of the auxiliary return path from the return path, the heat medium under the sieving by the sieving means is on the return path side, and the heat medium on the sieve is on the auxiliary return path side. By adhering to the heat transfer medium, the large agglomerated heat medium that clumps with the sticky deposit and remains on the sieve is selectively sent to the secondary return path, so that the sticky deposit is efficiently and preferentially from the heat medium with a large amount of sticky deposit. Can be removed.
[0015]
Each heat exchange apparatus mentioned above is suitable for the said high temperature exhaust gas being discharged | emitted from a melting furnace, and the main component of the said deposit | attachment being a metal chloride.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2 show a first embodiment. As shown in FIG. 1, this heat exchange apparatus has an upper heat exchange chamber 2 through which a high-temperature exhaust gas 1 from a melting furnace (not shown) flows and a lower heat exchange chamber 4 through which a low-temperature gas 3 such as the atmosphere flows up and down. These heat exchange chambers 2, 4 are communicated with each other through the communication part 5, and each of the heat exchange chambers 2, 4 is provided with a plurality of trays 6, 7. The granular heat medium 10 charged into the upper part of the upper heat exchange chamber 2 from the inlet 9 of the hopper 8 is divided into the trays 6 of the upper heat exchange chamber 2, the communication part 5, the trays 7 of the lower heat exchange chamber 4, and the lower part. It falls sequentially to the bottom of the heat exchange chamber 4, collects sensible heat in contact with the hot exhaust gas 1 flowing from the vent 11 to the exhaust port 12 in the upper heat exchange chamber 2, and vents in the lower heat exchange chamber 4. The sensible heat recovered in the low-temperature gas 3 flowing from 13 to the exhaust port 14 is released and heat exchange is performed. The heat medium 10 subjected to the heat exchange is returned to the hopper 8 through the return path 16 from the discharge port 15 provided at the bottom of the lower heat exchange chamber 4 and is circulated.
[0017]
The return path 16 is provided with a container 17 into which each heat medium 10 discharged from the discharge port 15 is put and the heat medium 10 is rubbed together. By the rubbing in the container 17, the heat medium 10 aggregated with the adhesive deposit mainly composed of the metal chloride contained in the high temperature exhaust gas 1 is crushed and the adhesive adhered to the surface of the heat medium 10. Also peel off adhesive deposits. The heat medium 10 from which the deposits have been removed by the container 17 is transferred to the air lifter 18, and is returned and conveyed by the air 19 through the return path 16 to the upper hopper 8. In addition, the exfoliated material is conveyed along the return path 16 together with the heat medium 10 by the air lifter 18 and enters the upper heat exchange chamber 2 from the hopper 8, but the exfoliated material is light so that it is exhausted together with the high-temperature exhaust gas 1 after heat exchange. It is discharged from the mouth 12 and collected by a bag filter (not shown) provided in the exhaust path.
[0018]
As shown in FIG. 2, the container 17 rolls while being supported by a roller 20 that is rotationally driven, and rubs the heat mediums 10 fed from the charging chute 21 to each other. The heat medium 10 from which the deposits are removed by this rubbing overflows from the discharge port 22 and is transferred to the air lifter 18. It is also possible to provide a large number of small holes in the container 17 to discharge the peeled off deposits, or to provide a screen on the transfer path to the air lifter 18 and to remove the peeled off deposits by this transfer path.
[0019]
3A and 3B show modified examples of the container 17, respectively. The container 17a shown in FIG. 3A is supported by a base 24 via a spring 23, and is vibrated by a vibration source 25 attached to the bottom thereof. The heat mediums 10 that are input from the upper input port 26a are rubbed against each other by this vibration, and deposits are removed and overflow from the output port 22a.
[0020]
In the container 17b of FIG. 3B, a horizontal rotating shaft 28 having a stirring blade 27 is passed inside, and the heat medium 10 is agitated by the stirring blade 27 by stirring the heat medium 10 charged from the charging port 26b. By rubbing, the deposit on the heat medium 10 is peeled off. The heat medium 10 from which the deposits have been removed overflows from the discharge port 22b. The container 17b is provided with a water supply port 29 and a water discharge port 30 for washing water, and the deposits separated from the heat medium 10 by stirring are discharged from the water discharge port 30 together with the washing water. Yes. Further, the metal chloride is water-soluble, and the metal chloride adhering to the heat medium 10 without peeling off is dissolved in the washing water by washing, so that the removal can be performed more reliably. The rotating shaft 28 of the stirring blade 27 may be vertical.
[0021]
FIG. 4 shows a second embodiment. This heat exchanging device is different from that of the first embodiment in the form of the return path 16. In this embodiment, a secondary return path 31 that branches from the return path 16 is provided, a sieve 32 is provided at the branch point, and the same adhesive deposit as in the first embodiment is peeled off from the secondary return path 31. A container 17 is provided. The heat medium 10 from which the deposits have been removed in the container 17 is transferred to the air lifter 33, and is returned and conveyed from the auxiliary return path 31 to the upper hopper 8 by the air 19. The other parts are the same as those in the first embodiment, and are therefore denoted by the same reference numerals as in FIG.
[0022]
In the sieve 32, the large aggregated heat medium 10 a that clumps with adhesive deposits and remains on the sieve is put into the container 17 on the side of the sub-return path 31, is crushed, and falls under the screen. 10 is transferred to the air lifter 18 on the return path 16 side and returned to the hopper 8 and conveyed.
[0023]
FIG. 5 shows a third embodiment. As in the second embodiment, this heat exchange device is provided with a secondary return path 31 that branches from the return path 16, and a sieve 32 is provided at the branch point. In this embodiment, a cleaning container 34 and a drying container 35 are provided in this order in the auxiliary return path 31, and the large agglomerated heat medium 10 a remaining on the sieve is cleaned with the cleaning water 36 in the cleaning container 34 and is adhered to the adhesive. And is further dried with dry air 37 in a drying container 35. The dried heat medium 10 is transferred to the air lifter 33 and is returned and conveyed from the auxiliary return path 31 to the hopper 8. The drying container 35 may be omitted.
[0024]
In each of the embodiments described above, the high-temperature exhaust gas for recovering sensible heat is discharged from the melting furnace, but the high-temperature exhaust gas discharged from an incinerator or the like can also be used.
[0025]
【The invention's effect】
As described above, the heat exchanging apparatus of the present invention is provided with a means for rubbing the heat mediums in the container in the return path for circulating the heat medium, and the heat medium aggregated with the highly adhesive metal chloride deposits. In addition, the adhesive material is peeled off from the surface of the heat medium by crushing and rubbing the heat medium together, so the adhesive material of the heat medium is efficiently used without heat loss. Can be removed well.
[0026]
In the heat exchange device of the present invention, a secondary return path that branches to a return path for circulating the heat medium is provided, and a cleaning means for the heat medium is provided in the secondary return path. The sticky deposits can be removed only with respect to the heat medium, and the sticky deposits on the heat medium can be sequentially and efficiently removed without causing a significant heat loss.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing a heat exchange device according to a first embodiment. FIG. 2 is a longitudinal sectional view showing a container of a return path in FIG. 1. FIG. FIG. 4 is a schematic longitudinal sectional view showing a heat exchange device according to a second embodiment. FIG. 5 is a schematic longitudinal sectional view showing a heat exchange device according to a third embodiment.
DESCRIPTION OF SYMBOLS 1 High temperature exhaust gas 2 Heat exchange chamber 3 Low temperature gas 4 Heat exchange chamber 5 Communication part 6, 7 Tray 8 Hopper 9 Input port 10, 10a Heat medium 11 Vent 12 Exhaust port 13 Vent port 14 Exhaust port 15 Exhaust port 16 Return path 17 17a, 17b Container 18 Air lifter 19 Air 20 Roller 21 Chute 22, 22a, 22b Discharge port 23 Spring 24 Base 25 Vibration sources 26a, 26b Input port 27 Stirrer blade 28 Rotating shaft 29 Water supply port 30 Drain port 31 Sub return path 32 Sieve 33 Air lifter 34 Cleaning container 35 Drying container 36 Cleaning water 37 Drying air

Claims (4)

The granular heat medium is passed from the upper heat exchange chamber in which the high-temperature exhaust gas circulates to the lower heat exchange chamber in which the low-temperature gas circulates to exchange heat with the gas flowing in each of these heat exchange chambers, and this heat-exchanged granular material In the heat exchange device in which the heat medium is circulated from the bottom of the lower heat exchange chamber to the upper heat exchange chamber through a return path, the heat medium is provided in a return path from an outlet provided in the bottom of the lower heat exchange chamber. A heat exchange device characterized in that means for rubbing each other in a container is provided to remove metal chlorides adhering to the surface of these heat media.   The heat exchange device according to claim 1, wherein a water supply port and a water discharge port for cleaning water are provided in a container for rubbing the heat media.   3. The heat exchange device according to claim 1, wherein a secondary return path that branches into the return path is provided, and a means for rubbing the heat mediums in a container is provided on the secondary return path side. A sieving means for the heat medium is provided at a branch point of the auxiliary return path from the return path, the heat medium under the sieving by the sieving means is on the return path side, and the heat medium on the sieve is on the auxiliary return path side. The heat exchange device according to claim 3 , wherein the heat exchange device is sent to the heat exchanger.

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