JPS6314221Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a heat exchanger for recovering sensible heat from high-temperature exhaust gas containing dust (ash, etc.) discharged from coal-fired boilers, etc., and particularly relates to a heat exchanger and a dust removal process. The present invention relates to a dust-containing gas heat exchanger that can perform heat exchange processing simultaneously and continuously.

Generally, high-temperature exhaust gas discharged from oil-fired, coal-fired boilers, etc. is released into the atmosphere after sensible heat is recovered from the viewpoint of effective energy use.

When recovering sensible heat, a heat pipe type heat exchanger is usually used since there is little risk of leakage.
Specifically, this heat exchanger is installed in an exhaust gas passage, and for example, one end of a heat pipe made of a heat medium sealed in the pipe is placed in high-temperature exhaust gas, and the other end is placed in a wet desulfurization device. It is placed within the incoming low-temperature gases to exchange heat with them.

By the way, high-temperature exhaust gas contains a large amount of dust generated by burning coal, etc. If this dust adheres to the heat pipe, it not only reduces the heat exchange efficiency but also causes sulfur oxides to be present in the exhaust gas. When the heat pipe contains dust, there is a problem that the heat pipe corrodes due to the synergistic effect of this and the adhered dust. For this reason, in the past, in order to remove dust adhering to the heat pipe, a cleaning device such as a shot cleaning device was installed in parallel with the heat exchanger, and the heat exchanger was periodically removed. Dust attached to the equipment had to be removed, making continuous stable operation impossible.

In order to correct this inconvenience, it has been attempted to remove dust from the exhaust gas in advance, but in this case a separate dust removal device must be provided, which is not preferred from the standpoint of efficient space utilization.

The present invention focuses on the above-mentioned problems and has been devised to effectively solve them.

The purpose of this invention is to use a heat pipe to exchange the sensible heat of high-temperature exhaust gas containing dust such as soot with low-temperature gas, and to prevent dust from adhering to the heat pipe, and to effectively remove dust from a dust-containing gas. Our purpose is to provide heat exchangers.

In order to achieve the above object, the present invention provides a heat exchanger for recovering the sensible heat of high-temperature exhaust gas containing dust by heat exchange with low-temperature gas. A heat pipe is inserted facing the high-temperature exhaust gas chamber and the low-temperature gas chamber to transfer heat via an enclosed heat medium, and the high-temperature exhaust gas chamber is connected to an inflow side and an outflow side. A partition plate that partitions the room and has a gas flow port into which a heat pipe in the room is loosely inserted, and a bottomed cylindrical dust removal filter that covers the outer periphery of the heat pipe facing the inflow side from the gas flow port at intervals. and configure it.

According to the above configuration, the high-temperature exhaust gas containing dust on the inflow side of the high-temperature exhaust gas chamber passes through the dust removal filter that covers the heat pipe at intervals, and the dust is removed from the high-temperature exhaust gas after dust removal. While flowing to the outflow side through the gas flow port of the partition plate while contacting the heat pipe, the heat medium sealed in the heat pipe is evaporated, and the evaporation medium radiates heat on the low temperature gas chamber side.
By condensing, the sensible heat of the high temperature exhaust gas can be heat exchanged with the low temperature gas. Moreover, since the high-temperature exhaust gas that comes into contact with the heat pipe is the gas that has been removed by the dust removal filter, there is no dust attached to the heat pipe, and a good heat exchange rate can be maintained.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, FIG. 1 is a longitudinal sectional view showing a heat exchanger according to the present invention, FIG. 2 is an enlarged view of section A in FIG. 1, and FIG.

As shown in the figure, the outer shell of this heat exchanger is constituted by a casing 1 formed into a substantially cylindrical shape. The inside of this casing 1 is divided into upper and lower halves by a partition tube plate 2, with a low-temperature gas chamber 3 through which low-temperature gas flows formed on the upper side, and a high-temperature exhaust gas chamber 4 through which high-temperature exhaust gas passes through on the lower side. It is formed. A casing side wall that partitions the low temperature gas chamber 3 is provided with a low temperature gas inlet 6 and a low temperature gas outlet 7 connected to the low temperature gas passage 5. Furthermore, a high temperature exhaust gas inlet 9 and a high temperature exhaust gas outlet 10 connected to the high temperature exhaust gas passage 8 are provided on the side wall of the casing that partitions the high temperature exhaust gas chamber 4 . This heat exchanger is interposed, for example, in a discharge passage for exhaust gas containing dust such as medium dust discharged from a coal-fired or oil-fired boiler. As the high-temperature exhaust gas 11, for example, a high-temperature exhaust gas transferred from a boiler to a wet desulfurization device is used, and as a low-temperature gas 12, a low-temperature gas transferred from a wet desulfurization device toward a chimney in order to prevent white smoke formation is used. This will be heated and then released into the atmosphere.

Inside the casing 1, a large number of heat pipes 13 are provided which vertically penetrate the partition tube plate 2 and are supported by it to communicate the low temperature gas chamber 3 and the high temperature exhaust gas chamber 4. This heat pipe 13 is made of aluminum, stainless steel,
A pipe made of steel or other material filled with a heat medium such as water, freon, or ammonia.The medium is heated and evaporated at the bottom end, moves to the top end, radiates heat, and is condensed there, returning to its original liquid state. Heat is transferred by flowing down inside and returning to the bottom end. A spiral fin 14 is attached to the heat pipe 13 along its longitudinal direction in order to increase the contact area with the gas. A dust removal filter 15, which is a feature of the present invention, is provided in the high-temperature exhaust gas chamber 4 for removing or filtering dust in the exhaust gas introduced from the high-temperature exhaust gas inlet 9. As shown in FIG. 2, the dust removal filter 15 includes a partition plate 16 installed horizontally above the high-temperature exhaust gas inlet 9 to vertically divide the interior of the high-temperature exhaust gas chamber 4 into two, and a filter cloth 17 attached to the partition plate 16. It is composed of. Specifically, a circular gas flow port 18 of a predetermined size is bored in the partition plate 16, and the heat pipe 13 is inserted through the center of the gas flow port 18. The heat pipe 13 extending downward from the gas flow port 18 is covered with a cylindrical filter cloth 17 having a predetermined mesh. It is installed freely. As shown in FIG. 3, ring-shaped filter cloth shape maintaining members 19 molded to have approximately the same diameter as the inner diameter of the filter cloth are attached at predetermined intervals in the longitudinal direction of the heat pipe 13. A circular flat filter cloth shape maintaining member 20 is also attached to the lower end of the filter cloth 17 to stabilize the shape of the filter cloth 17. Therefore, the high-temperature exhaust gas from which dust has been removed by passing through the filter cloth 17 comes into contact with the heat pipe 13 and passes through the gas flow port 18.
will go up through the.

The filter cloth 17 used here is of course heat-resistant treated, and its mesh is changed depending on the fuel used to ensure proper dust removal.

Further, the total area of the gas flow ports 18 formed in the partition plate 16 is ensured to be sufficiently large to the extent that it does not hinder exhaust gas discharge.

A dust discharge port 20 formed in the shape of an inverted cone is provided at the lower end of the casing 1 to discharge the dust separated by the dust removal filter 15.

Although the illustrated example shows four heat pipes 13 per row, it goes without saying that the number can be increased depending on the capacity of the heat exchanger and the length can be selected as appropriate.

Next, the operation of the present invention will be described.

First, high-temperature exhaust gas 11 containing dust such as medium dust discharged from a boiler or the like is introduced into high-temperature exhaust gas chamber 4 in the lower part of the casing via high-temperature exhaust gas inlet 9. After the dust contained in the gas is removed by the filter cloth 17 of the dust removal filter 15, this high-temperature exhaust gas contacts the heat pipe 13 to heat and vaporize the heat medium in the pipe. The heat-exchanged exhaust gas rises and passes through the gas flow port 18 and the high-temperature exhaust gas outlet 10.
It is discharged to the outside of the casing via the casing, and then transferred to a wet desulfurization device (not shown).

On the other hand, the high-humidity low-temperature gas discharged from the wet desulfurization device is circulated in the low-temperature gas chamber 3 in the upper part of the casing, and this gas comes into contact with the heated heat pipe 13 and is heated, so that the high-temperature exhaust gas This means that the heat is indirectly exchanged with the casing and is discharged outside the casing.

In this way, by covering the heat pipe 13 extending into the high-temperature exhaust gas chamber 4 with the filter cloth 17, clean gas from which dust has been filtered is transferred to the heat pipe 1.
3, so dust does not adhere to the pipe. Therefore, corrosion of the pipes and reduction in heat exchange efficiency due to adhesion of dust will not occur. The removed dust 21 falls from the filter cloth 17 and is discharged from the dust outlet 20 to the outside of the casing.

Furthermore, in order to improve the dust removal efficiency, it is necessary to maintain the filter cloth 17 in a predetermined cylindrical shape, but in this embodiment, by attaching a simple filter cloth-shaped member 19 to the heat pipe 13, the heat pipe The shape of the filter cloth 17 can be supported by itself. Therefore, it is possible to significantly save space compared to providing a dust filter and a heat pipe separately.

Furthermore, since the dust removed by the filter cloth 17 is sequentially discharged, continuous operation of the heat exchanger is possible without stopping the operation. If the filter cloth becomes clogged with dust, the filter cloth should be cleaned using a normal backwashing method.

Incidentally, the attachment structure between the filter cloth and the heat pipe is not limited to the above embodiment, and may be as shown in FIGS. 4, 5, 6, and 7.

First, as shown in FIGS. 4 and 5, disc-shaped fins 22 are formed in multiple stages at predetermined intervals along the longitudinal direction of the heat pipe 13, and a large number of ventilation holes 23 are formed in the fins 22. . and,
The fins 22 are used as filter cloth shape maintaining members, and the filter cloth 17 is supported by the fins 22 so as to cover the entire heat pipe.

According to this, since the cylindrical filter cloth 17 is supported by the wide disc-shaped fins 22, it is possible to eliminate the need for a special filter cloth shape maintaining member, which was required in the above embodiment, and to improve the filtering performance. The gas is Finn 22
Since the air rises sequentially through a large number of ventilation holes 23 formed in the air, problems such as blockage do not occur.

Further, in the case shown in FIGS. 6 and 7, fins 24 arranged radially around the heat pipe 13 are attached linearly for a predetermined length along the longitudinal direction of the pipe, and the fins 24 are installed linearly along the longitudinal direction of the pipe. A cylindrical filter cloth 17 is provided to cover the filter 24. In the illustrated example, eight fins 24 are provided, but the number is not limited to this, and the fins may be provided over the entire length of the pipe.

According to this illustrated example, the high-temperature exhaust gas from which dust has been filtered rises through the gaps formed between the fins, and the pressure loss of the exhaust gas can be extremely reduced.

Furthermore, as shown in FIG.
The heat pipes are connected and arranged in a rectangular shape, and the entire group of heat pipes is covered with a filter cloth 17. Then, the filtered exhaust gas may be raised into the gap formed between these heat pipes.

In the above embodiments, we have mainly explained the case where the heat exchanger according to the present invention is installed in the exhaust gas passage of a coal-fired boiler, but what will happen if heat exchange is performed with gas containing dust? It can be applied to anything.

In summary, according to the present invention, the following excellent effects can be achieved.

(1) Heat can be exchanged between high-temperature exhaust gas containing dust and low-temperature gas without leakage, and at the same time, dust can be removed from the high-temperature exhaust gas.

(2) Since there is no dust attached to the heat pipe, not only can the heat exchange efficiency be improved, but also continuous operation of the heat exchanger is possible.

(3) In addition, since there is no dust attached to the heat pipe, the influence of sulfur oxides can be reduced and corrosion of the heat pipe can be prevented.

(4) Since the heat pipe itself supports the filter cloth or dust removal filter and integrates them, space can be used more effectively than when a dust removal device is provided separately.

(5) Since the structure is simple, it can be easily adopted into existing equipment.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing a preferred embodiment of the present invention, Fig. 2 is an enlarged view of section A in Fig. 1, and Fig. 3 is an enlarged view of section A in Fig. 1.
4 is a perspective view showing a modified example of the heat pipe, FIG. 5 is an enlarged sectional view taken along the line in FIG. 4, and FIG. 6 is another modification of the heat pipe. A perspective view showing an example, Fig. 7 is in Fig. 6 -
FIG. 8, an enlarged sectional view taken along the line, is a sectional view showing still another modification of the heat pipe. In the figure, 1 is the casing, 3 is the low-temperature gas chamber, and 4 is the casing.
11 is a high temperature exhaust gas chamber, 11 is a high temperature exhaust gas, 12 is a low temperature gas, 13 is a heat pipe, 15 is a dust removal filter, 17 is a filter cloth, and 21 is a dust component.

Claims (1)

[Scope of utility model registration request] A heat exchanger that recovers the sensible heat of high-temperature exhaust gas containing dust by heat-exchanging it with low-temperature gas, comprising: a high-temperature exhaust gas chamber through which the high-temperature exhaust gas flows; a low-temperature gas chamber through which the low-temperature gas flows; and these high-temperature exhaust gas chambers. A heat pipe is inserted facing the low-temperature gas chamber and transfers heat via an enclosed heat medium, and the high-temperature exhaust gas chamber is partitioned into an inflow side and an outflow side, and the heat pipe in the chamber is loosely inserted. A dust-containing gas heat source characterized by comprising a partition plate having a gas distribution port, and a bottomed cylindrical dust removal filter that covers the outer periphery of the heat pipe facing the inflow side from the gas distribution port at intervals. exchanger.