JP6712902B2 - Waste treatment facility - Google Patents

Description

The present invention relates to waste treatment equipment.

Organic sludge generated by biological treatment using microorganisms is incinerated or melted in a waste treatment facility equipped with heat treatment furnaces such as incinerators, melting furnaces and shaft furnaces after solid-liquid separation and adjustment to an arbitrary water content. Is being processed. A heat exchanger is arranged in the flue of the heat treatment furnace in order to preheat the combustion air supplied to the heat treatment furnace with the heat of the exhaust gas generated in the heat treatment furnace.

FIG. 12(a) shows a conventional heat exchanger used for such an application. A tubular casing 100 having an inflow portion 101 and an outflow portion 102 for the combustion air that serves as a heat receiving side fluid, and an upper tube sheet 103 and a lower tube sheet 104 welded to the upper end side and the lower end side of the tubular casing 100, respectively. , A shell-and-tube type heat exchanger including a plurality of heat transfer tubes 105 that are welded and supported by the upper tube sheet 103 and the lower tube sheet 104 and that are arranged in a vertical posture in the tubular casing 100 and through which exhaust gas that is a fluid on the heat radiation side flows. It is an exchange.

The upper and lower tube plates 103 and 104 that bundle and support a plurality of heat transfer tubes are important strength members that receive a reaction force generated by thermal expansion of the heat transfer tubes 105 caused by the load of the heat transfer tubes 105 and high-temperature exhaust gas. If the tube plates 103, 104 are distorted and damaged by the expansion of the heat transfer tube 105, the airtightness of the heat exchanger may be impaired, and stable operation of the equipment may be hindered. In particular, when the outlet temperature of the combustion air, which is the heat receiving fluid, is set to be high in order to save energy, it is desirable that the inlet temperature of the exhaust gas, which is the heat radiating fluid, is also as high as possible. There is a risk that the risk of damage due to the heat load on the members may increase.

Therefore, as shown in FIG. 12B, in Patent Document 1, an exhaust gas introduction chamber 201 for introducing the high temperature exhaust gas of a heat source device such as an incinerator, and the high temperature exhaust gas and preheating formed in the outer cylinder 200 A heat exchange chamber 202 for exchanging heat with air and an exhaust gas discharge chamber 203 for discharging the heat-exchanged low temperature exhaust gas, and a high temperature side tube sheet 204 separating the exhaust gas introduction chamber 201 and the heat exchange chamber 202, and the heat exchange chamber A low temperature side tube sheet 205 that separates 202 from the exhaust gas exhaust chamber 203, and upper and lower ends thereof are connected to the high temperature side tube sheet 204 and the low temperature side tube sheet 205, respectively, and communicate with the exhaust gas introduction chamber 201 and the exhaust gas exhaust chamber 203. A plurality of heat transfer tubes 206, a sub chamber 207 installed on the heat exchange chamber 202 side of the high temperature side tube sheet 204, a preheating air introduction port 208 for introducing preheating air into the sub chamber 207, and the sub chamber A return pipe 209 that extends from the chamber 207 to the heat exchange chamber 202 and allows the preheating air to flow out below the heat exchange chamber 202, and the heat source device that discharges the preheating air from the heat exchange chamber 202. A multi-tube heat exchanger including a preheated air discharge port 210 for supplying the heat to the air has been proposed.

Further, as shown in FIG. 12C, in Patent Document 2, an outer cylinder portion 300 provided with an inlet 301 and an outlet 302 of a fluid to be heated, an inflow header 303 into which a heat source fluid flows, An outflow header 304 through which the heat source fluid flows out, and a plurality of heat transfer tubes 305 that connect the inflow header 303 and the outflow header 304 to each other are communicatively provided, and a high temperature side tube sheet portion 306 is provided on one end side of the outer tubular portion 300. Through the low temperature side tube sheet part 307 to the other end side of the outer cylinder part 300 to connect the inflow header 303 to the heat transfer pipe 305. The first tube is provided by inserting the first tube sheet 310 on the outer tube section 300 side and the second tube sheet 311 on the inflow header 303 side into the high temperature side tube sheet section 306. A multi-tube heat exchanger has been proposed in which a cooling space 312 through which a tube plate cooling fluid can flow is formed between a plate 310 and the second tube plate 311.

In the multi-tube heat exchanger, a through hole 313 that communicates the cooling space 312 and the inside of the outer tubular portion 300 is provided at substantially the center of the first tube sheet 310, and the pressure difference is utilized to The high temperature side tube sheet portion is configured to be cooled by taking the heated fluid as the tube sheet cooling fluid from the through hole 313 into the cooling space and flowing the cooling space 312. There is.

JP, 2010-144999, A Japanese Patent No. 4194595

In each of the multi-tube heat exchangers disclosed in Patent Documents 1 and 2, the tube plate on the inlet side of the heat radiation side fluid is configured as a double tube plate, and cooling air is supplied to the area surrounded by the double tube plate. In this configuration, the tube sheet is cooled to supply cooling air from the outside by using a dedicated blower fan (see FIG. 12(b)), or a part of the heat receiving side air is branched to cool the tube sheet from the inside. A structure that supplies air (see FIG. 12C) is adopted.

According to the conventional shell-and-tube heat exchanger described above, the heat load on the upper tube sheet is reduced, so that high-temperature exhaust gas can be used as the heat source, but the center of the heat transfer tubes is arranged. Since the return pipe 209 (see FIG. 12B) and the through hole 313 (see FIG. 12C) are provided in the portion, the heat transfer area for one heat transfer tube is reduced.

In addition, since both ends of the heat transfer tube are welded to the upper and lower tube plates, the tube plate is subject to bending stress due to thermal expansion of the heat transfer tube, and the risk of breakage cannot be eliminated.

In view of the above-mentioned problems, the object of the present invention is to reduce the reaction force applied to the tube sheet due to the thermal expansion of the heat transfer tube, and further to efficiently cool the tube sheet without reducing the heat transfer area. The point is to provide a waste treatment facility equipped with a heat exchanger.

In order to achieve the above-mentioned object, the first characteristic constitution of the waste treatment facility according to the present invention is to preheat the heat treatment furnace and the combustion air of the heat treatment furnace by the heat of exhaust gas installed in the flue of the heat treatment furnace. A waste treatment facility including a heat exchanger, wherein the heat exchanger is fixed to a casing having an inflow portion and an outflow portion of combustion air, and is fixed to an upper end side and a lower end side of the casing, respectively. An upper tube sheet and a lower tube sheet, and a plurality of heat transfer tubes supported by the upper tube sheet and the lower tube sheet and arranged in the casing, through which exhaust gas flows, one end of the heat transfer tube Slides with a guide tube fixed to either the upper tube sheet or the lower tube sheet, and the other end of the heat transfer tube is fixedly supported to the other of the upper tube sheet or the lower tube sheet. Of the upper tube plate or the lower tube plate, facing the tube plate on the exhaust gas inflow side, inside the casing, fixed only to the heat transfer tube, and integrally with the heat transfer tube with respect to the tubular casing. A relatively movable partition tube plate is arranged, a cooling space is formed between the tube plate and the partition tube plate, and cooling air supplied to the cooling space is the outer peripheral portion of the partition tube plate and the cooling air. It is configured to flow out from a gap formed between the inner wall surface of the cylindrical casing facing the outer peripheral portion and to be mixed with the combustion air in the casing.

A guide tube is fixed to either the upper tube sheet or the lower tube sheet, one end of the heat transfer tube is slidably arranged with the guide tube, and the other end of the heat transfer tube is attached to the other tube sheet. It is fixedly supported. Even when the heat transfer tube fixedly supported by the tube plate expands in the tube axis direction due to thermal stress, the heat transfer tube slides against the guide tube, and the heat transfer tube is large directly on both the upper tube plate and the lower tube plate. Since no reaction force is applied, no large strain is generated in both tube sheets. Therefore, it is possible to obtain a waste treatment facility that can reduce the risk of damage to structural members such as the tube sheet due to thermal stress, while increasing the efficiency of exhaust heat recovery and energy saving.

And, the space between the tube plate on the inflow side of the exhaust gas and the partition tube plate arranged facing the tube plate becomes a cooling space, and the inflow side of the exhaust gas is supplied by the cooling air supplied to the cooling space. The tube sheet will be cooled effectively. Then, the cooling air merges with the combustion air that becomes the heat receiving side fluid through the gap between the tubular casing and the partition tube plate, so that the conventional return pipe 209 (see FIG. 12B) and the through hole 313 (see FIG. The heat transfer tube can be arranged also in the space where the special flow passage part such as FIG. 12C) is provided, and the heat transfer area can be increased.

Further, when arranging the partition tube plate with a gap to the cylindrical casing, the partition plate can be fixed to the heat transfer tube, and in that case, the heat transfer tube extending by thermal expansion and the tubular casing can be fixed to the cylindrical casing. As a result, the partition tube plate will not be abnormally distorted.

The second characteristic configuration is a waste treatment facility equipped with a heat treatment furnace and a heat exchanger installed in a flue of the heat treatment furnace to preheat combustion air of the heat treatment furnace by heat retained by exhaust gas. The heat exchanger includes a casing having an inflow portion and an outflow portion for combustion air, an upper tube plate and a lower tube sheet fixed to upper and lower ends of the casing, and the upper tube sheet. And a plurality of heat transfer tubes supported by the lower tube sheet and arranged in the casing, through which exhaust gas flows, and one end of the heat transfer tube is one of the upper tube sheet and the lower tube sheet. The other end of the heat transfer tube is fixedly supported on the other of the upper tube plate or the lower tube plate while sliding with the guide tube fixed to the upper tube plate or the lower tube plate. A partition tube plate, which is fixed only to the heat transfer tube and is movable relative to the tubular casing integrally with the heat transfer tube, is arranged inside the casing so as to face the tube plate provided with the guide tube. A cooling space is formed between the plate and the partition tube plate, and cooling air supplied to the cooling space is an outer wall of the partition tube plate and an inner wall surface of the tubular casing facing the outer wall. It is configured so that it flows out from the gap formed between the two and mixes with the combustion air in the casing.

A guide tube is fixed to either the upper tube sheet or the lower tube sheet, one end of the heat transfer tube is slidably arranged with the guide tube, and the other end of the heat transfer tube is attached to the other tube sheet. It is fixedly supported. Even when the heat transfer tube fixedly supported by the tube plate expands in the tube axis direction due to thermal stress, the heat transfer tube slides against the guide tube, and the heat transfer tube is large directly on both the upper tube plate and the lower tube plate. Since no reaction force is applied, no large strain is generated in both tube sheets. Therefore, it is possible to obtain a waste treatment facility that can reduce the risk of damage to structural members such as the tube sheet due to thermal stress, while increasing the efficiency of exhaust heat recovery and energy saving.

Then, the space between the tube sheet provided with the guide tube and the partition tube sheet arranged so as to face the tube sheet becomes a cooling space, and the inflow side of the exhaust gas by the cooling air supplied to the cooling space. The tube sheet will be cooled effectively. Then, the cooling air merges with the combustion air that becomes the heat receiving side fluid through the gap between the tubular casing and the partition tube plate, so that the conventional return pipe 209 (see FIG. 12B) and the through hole 313 (see FIG. The heat transfer tube can be arranged also in the space where the special flow passage part such as FIG. 12C) is provided, and the heat transfer area can be increased.

Further, when arranging the partition tube plate with a gap to the cylindrical casing, the partition plate can be fixed to the heat transfer tube, and in that case, the heat transfer tube extending by thermal expansion and the tubular casing can be fixed to the cylindrical casing. As a result, the partition tube plate will not be abnormally distorted.

The third characteristic configuration is that, in addition to the above-described first or second characteristic configuration, the guide tube is configured such that the heat transfer tube can be inserted or externally inserted.

When the heat transfer tube is inserted into the guide tube, the outer peripheral wall of the heat transfer tube slides along the inner peripheral wall of the guide tube, and when the heat transfer tube is externally inserted into the guide tube, the heat transfer tube extends along the outer peripheral wall of the guide tube. The inner peripheral wall of the device slides, and no matter how the structure is applied, a large reaction force does not directly act on either the upper tube plate or the lower tube plate against the expansion of the heat transfer tube in the tube axis direction. ..

In the fourth characteristic configuration, in addition to any one of the first to third characteristic configurations described above, the casing has a substantially vertical cylindrical shape, and the heat transfer tubes are arranged in an axial direction of the casing. There is a point.

Since the heat transfer tubes are arranged in the axial direction of the casing, that is, in a substantially vertical direction, the heat transfer tubes do not bend in the direction intersecting the axis due to their own weight, and as a result, the contact portion between the guide tube and the heat transfer tube is biased. Instead, it will slide substantially evenly.

In the fifth characteristic configuration, in addition to any one of the first to fourth characteristic configurations described above, the guide tube is provided in a tube plate on an exhaust gas inflow side of the upper tube plate or the lower tube plate. There is a point.

A large heat load is applied to the tube plate on the inflow side of the high-temperature exhaust gas that serves as the heat radiation side fluid. Since a guide tube on which the heat transfer tube can slide is provided on such a tube plate, the heat load due to the thermal expansion of the heat transfer tube does not directly act on the tube plate, so that there is a great risk of damage. Will be reduced to.

In the sixth characteristic configuration, in addition to any one of the first to fourth characteristic configurations described above, the guide tube is provided in a tube plate on the exhaust gas outflow side of the upper tube plate or the lower tube plate. The inflow part of the combustion air is provided on the inflow side of the exhaust gas.

Even when a guide tube is provided on the tube plate on the exhaust gas outflow side, the heat transfer tube that thermally expands slides on the guide tube, so the heat load due to the thermal expansion of the heat transfer tube is applied to the tube plate on the exhaust gas inflow side. There is no direct action. Moreover, the low-temperature combustion air before heat exchange, which has flowed in from the inflow portion provided on the inflow side of the exhaust gas, also effectively cools the tube plate on the inflow side of the high temperature exhaust gas.

In the seventh characteristic configuration, in addition to any one of the first to sixth characteristic configurations described above, the exhaust gas pressure is P1, the combustion air pressure is P2, and the cooling air pressure is P3. In this case, P1<P2<P3 is set.

If at least the relationship of P1<P2<P3 is established among the pressure P1 of the exhaust gas, the pressure P2 of the combustion air and the pressure P3 of the cooling air, the cooling air supplied to the cooling space is retained. Instead, it merges with the combustion air serving as the heat receiving side fluid through the gap between the tubular casing and the partition tube sheet or the gap between the heat transfer tube and the partition tube sheet, or is transferred through the guide tube that constitutes the sliding portion. As a result, the heat can be reliably introduced into the heat pipe, and a sufficient cooling effect can be obtained even with a small amount of cooling air.

As described above, according to the present invention, the heat exchange that can reduce the reaction force applied to the tube sheet due to the thermal expansion of the heat transfer tube, and further can efficiently cool the tube sheet without reducing the heat transfer area. It has become possible to provide a waste treatment facility equipped with a container.

1A is a vertical cross-sectional view of the heat exchanger of the present invention, and FIG. 1B is a cross-sectional view taken along the line BB of FIG. 1A. Explanatory drawing of a waste treatment facility incorporating a heat exchanger according to the present invention Explanatory drawing of an embodiment of a countercurrent heat exchanger with lower support and heat transfer tube insertion Explanatory drawing of an embodiment of a countercurrent heat exchanger with a lower support and a heat transfer tube extrapolation Explanatory drawing of an embodiment of a lower support, countercurrent heat exchanger Explanatory drawing of an embodiment of an upper support and countercurrent heat exchanger Explanatory drawing of an embodiment of an upper support and a parallel flow heat exchanger In another embodiment of the heat exchanger having no cooling space, (a) is a lower support and an explanatory view of a countercurrent heat exchanger, and (b) is an upper support, an explanatory view of a cocurrent heat exchanger. In another embodiment of the heat exchanger having no cooling space, (a) is a lower support and an explanatory view of a co-current heat exchanger, and (b) is an upper support, an explanatory view of a countercurrent heat exchanger. In another embodiment of the heat exchanger having no cooling space, (a) is a lower support, and an explanatory view of the countercurrent heat exchanger, and (b) is an upper support, an explanatory view of the countercurrent heat exchanger. Explanatory drawing of the waste treatment equipment which showed another embodiment and which incorporated the heat exchanger by this invention. Illustration of conventional heat exchanger

Hereinafter, embodiments of the heat exchanger and the waste treatment facility according to the present invention will be described.
FIG. 2 shows a waste treatment facility 1 that incinerates waste such as sludge. A fluidized bed incinerator 2 which is an example of a waste treatment furnace, a heat exchanger 3 which preheats combustion air by the retained heat of exhaust gas generated in the fluidized bed incinerator 2, and a flue gas are arranged. Exhaust gas treatment equipment such as a dust collector 9 and a smoke exhaust treatment tower 10 and a chimney 12 for exhausting the treated exhaust gas are provided. An induction blower 11 for maintaining a negative pressure in the furnace is provided on the downstream side of the smoke exhaust treatment tower 10, and the exhaust gas attracted by the induction blower 11 is exhausted from the chimney 12.

The fluidized bed incinerator 2 is a fluidized bed formed by high temperature air supplied from a forced air blower 6 serving as an air supply mechanism A, which heats the sludge put in the furnace and freeboards the gasified sludge. It is a processing furnace that is burned in a part.

The combustion air supplied from the forced air blower 6 is heat-exchanged with the exhaust gas at 800 to 1000° C. by the heat exchanger 3 and preheated to 500 to 750° C., and then supplied to the fluidized bed incinerator 2 to be fluidized bed. Is formed.

If a higher temperature exhaust gas is introduced in order to raise the temperature of the combustion air in the heat exchanger 3, there is a problem that an extremely large heat load is applied to the heat exchanger 3. The waste treatment facility according to the present invention incorporates the heat exchanger 3 provided with measures against such heat load.

1(a) and 1(b) show a cross section of a heat exchanger 3 according to the present invention. The heat exchanger 3 is fixed to, and specifically welded to, a tubular casing 39 having a combustion air inflow portion 50 and a combustion air outflow portion 43 and having a circular cross section, and an upper end side and a lower end side of the tubular casing 39, respectively. (Also referred to as “welding” in the following description), the upper tube plate 34 and the lower tube plate 35 are supported by the upper tube plate 34 and the lower tube plate 35, and a vertical posture in the tubular casing 39, specifically, Is provided with a plurality of heat transfer tubes 36 arranged in a vertical posture and through which the exhaust gas C flows.

The upper end of the heat transfer tube 36 has a sliding portion 38 inserted in a guide tube 37 welded to the upper tube sheet 34, and the other end of the heat transfer tube 36 is welded to and supported by the lower tube sheet 35.

An exhaust gas inflow header section 48 for inflowing the exhaust gas C into the heat transfer tube 36 is provided on the upper end side of the cylindrical casing 39, and an exhaust gas outflow header section 47 for collecting and discharging the exhaust gas C passing through the heat transfer tube 36 is provided at the lower end side. It is provided.

Inside the cylindrical casing 39, a plurality of baffle plates 40 are arranged alternately along the longitudinal direction of the heat transfer tube 36. The combustion air D that has flowed in from the combustion air inflow passage 31 provided in the jacket portion 33 that is a ventilation path rises while meandering along the baffle plate 40, and flows out to the combustion air outflow portion 32. That is, this meandering flow path forms the air flow path 41.

The exhaust gas C that has flowed in from the exhaust gas inflow header portion 48 flows down the heat transfer pipe 36 through the sliding portion 38, and flows out to the outflow header portion 47. Combustion air D flowing from the combustion air inflow portion 31 of the jacket portion 33 formed in the lower portion of the tubular casing 39 flows through the air flow path 41, and the combustion air D of the jacket portion 33 disposed in the upper portion of the tubular casing 39. It flows out from the combustion air outflow portion 32. A countercurrent heat exchanger 3 is configured in which heat is exchanged between exhaust gas, which is a heat-radiating fluid that flows down the heat transfer tube 36, and combustion air, which is a heat-receiving fluid that rises in the air flow path 41. There is.

A partition tube plate 49 is arranged facing the upper tube plate 34 with a space therebetween, and a cooling space 44 is formed between the upper tube plate 34 and the partition tube plate 49. Combustion air D is supplied from the opening 42 provided in the cooling space 44, and the upper tube sheet 34 and the vicinity of the upper tube sheet 34 heated by the high-temperature exhaust gas before heat exchange are configured to be cooled. ..

In this embodiment, the heat exchanger 3 accommodates 120 heat transfer tubes 36 having a diameter of about 70 mm in a cylindrical casing 39 having a length of about 12 m and a diameter of about 2 m. The heat transfer tube 36 is formed to have a length of about 10 m in the axial direction, and can be stretched by about 100 mm during thermal expansion.

The sliding portion 38 and the cooling mechanism will be described in detail with reference to FIG.
A plurality of openings are formed in the upper tube plate 34 at positions corresponding to the insertion positions of the heat transfer tubes 36, and short guide tubes 37 are inserted into the respective openings. It is welded and fixed at each opening.

The upper end side of the heat transfer tube 36 whose lower end side is welded and fixed to the lower tube sheet 35 is inserted into the guide tube 37 to form the sliding portion 38. When the exhaust gas flows into the heat transfer tube 36 and is heated, and the heat transfer tube 36 extends in the axial direction, the upper end side of the heat transfer tube 36 extends upward along the guide tube 37, and thus the upper tube sheet 34 and the lower tube sheet 35. Does not receive a reaction force due to the thermal expansion of the heat transfer tube 36, so that the strain generated in the upper tube sheet 34 and the lower tube sheet 35 is reduced. In FIG. 3, the heat transfer tube 36 expanded (expanded) by heat is shown by a broken line.

The guide tube 37 is formed in such a length that it can maintain the inserted state of the heat transfer tube 36 regardless of whether the heat transfer tube 36 is contracted in a normal temperature state or expanded in a heated state. Good. In addition, the inner diameter of the guide tube 37 is formed to be substantially the same as or slightly larger than the outer diameter of the heat transfer tube 36, so that when the heat transfer tube 36 is extended, it can be slid and extended with the inner peripheral portion of the guide tube 37. It only needs to be formed to the size.

A plurality of openings for inserting the heat transfer tubes 36 are formed in a partition tube plate 49 that forms a cooling space 44 with the upper tube sheet 34, and the openings and the heat transfer tubes 36 are welded to each other. .. Further, the outer peripheral portion of the partition tube plate 49 is opened without being welded to the tubular casing 39 and forming a very small gap.

Therefore, when the exhaust gas flows down into each heat transfer tube 36 to raise the temperature and the heat transfer tube 36 thermally expands and extends in the axial direction, the partition tube plate 49 is integrated with the heat transfer tube 36 as the heat transfer tube 36 thermally expands. Is configured to move relative to the tubular casing 39. Therefore, no reaction force is generated in the partition tube plate 49 due to the thermal expansion of the heat transfer tube 36.

As shown in FIG. 1, a jacket for supplying cooling air is connected to a jacket portion 33 for supplying combustion air. The cooling air supplied from the cooling air inflow portion 30 formed in the cooling air supply jacket is supplied to the cooling space 44 through the opening 42 formed on the upper end side of the tubular casing 39, and the upper tube sheet is formed. 34 and its surroundings are cooled, thereby reducing the heat load on the upper tube sheet 34.

In other words, the cooling mechanism is configured by the cooling space 44 partitioned by the upper tube sheet 34 and the partition tube sheet 49 and the cooling air supply jacket.

The cooling air supplied to the cooling space 44 cools the upper tube sheet 34, and then passes through a minute gap formed between the outer peripheral portion of the partition tube sheet 49 and the cylindrical casing 39, and the air flow path 41. And flows out into the exhaust gas side through a minute gap between the guide tube 37 and the heat transfer tube 36 forming the sliding portion 38. Since the flow rate of the cooling air supplied to the cooling space 44 is relatively small, even if mixed with the exhaust gas before heat exchange, the temperature of the exhaust gas does not decrease.

FIG. 4 shows another example of the sliding portion 38 and the cooling mechanism.
Similar to FIG. 3, a plurality of openings are formed in the upper tube sheet 34 at positions corresponding to the insertion positions of the heat transfer tubes 36, and short guide tubes 37 are inserted into the respective openings, and a peripheral portion of the guide tube 37 is formed. Are welded and fixed in the respective openings of the upper tube sheet 34. Hereinafter, points different from FIG. 3 will be described in detail.

The upper end side of the heat transfer tube 36, the lower end side of which is welded and fixed to the lower tube sheet 35, is externally inserted into the guide tube 37 to form a sliding portion 38. When the exhaust gas flows into the heat transfer tube 36 and is heated, and the heat transfer tube 36 extends in the axial direction, the upper end side of the heat transfer tube 36 extends upward along the guide tube 37, so that the upper tube sheet 34 and the lower tube sheet 35. Does not receive a reaction force due to thermal expansion of the heat transfer tube 36, and therefore, similarly to FIG. 3, the strain generated in the upper tube sheet 34 and the lower tube sheet 35 is reduced.

The guide tube 37 is formed in such a length that the heat transfer tube 36 can be kept in the inserted state regardless of whether the heat transfer tube 36 is contracted at room temperature or when it is heated. Good. Further, the outer diameter of the guide tube 37 is formed to be approximately the same size as or slightly smaller than the inner diameter of the heat transfer tube 36, and the guide tube 37 can be slid and extended with the outer peripheral portion of the guide tube 37 when the heat transfer tube 36 is extended. It may be formed on. In FIG. 4, the heat transfer tube 36 expanded (expanded) by heat is shown by a broken line.

FIG. 5 shows still another example of the sliding portion 38 and the cooling mechanism.
Similar to FIG. 3, a plurality of openings are formed in the upper tube sheet 34 at positions corresponding to the insertion positions of the heat transfer tubes 36, and short guide tubes 37 are inserted into the respective openings, and a peripheral portion of the guide tube 37 is formed. Are welded and fixed in the respective openings of the upper tube sheet 34. Hereinafter, points different from FIG. 3 will be described in detail.

A plurality of openings through which the heat transfer tubes 36 are inserted are formed in the partition tube plate 49 that forms the cooling space 44 with the upper tube sheet 34, and each opening and each heat transfer tube 36 have a slight gap therebetween. It is open apart. The outer peripheral portion of the partition tube plate 49 is welded to the inner peripheral portion of the tubular casing 39.

Therefore, when the exhaust gas flows down into each heat transfer tube 36 to raise the temperature and the heat transfer tube 36 thermally expands and extends in the axial direction, the partition tube plate 49 and the heat transfer tube 36 are separated by the thermal expansion of the heat transfer tube 36. It is configured to move relative to each other. Therefore, no reaction force is generated in the partition tube plate 49 due to the thermal expansion of the heat transfer tube 36. In FIG. 5, the heat transfer tube 36 expanded (expanded) by heat is shown by a broken line.

FIG. 6 shows still another example of the sliding portion 38 and the cooling mechanism.
A plurality of openings are formed in the lower tube plate 35 at positions corresponding to the insertion positions of the heat transfer tubes 36, and short guide tubes 37 are inserted into the respective openings. It is welded and fixed at each opening.

The lower end side of the heat transfer tube 36 whose lower end side is welded and fixed to the upper tube sheet 34 is inserted into the guide tube 37 to form the sliding portion 38. When the exhaust gas flows into the heat transfer tube 36 and is heated and the heat transfer tube 36 extends in the axial direction, the lower end side of the heat transfer tube 36 extends downward along the guide tube 37, so that the lower tube sheet 35 and the upper tube sheet 34 are There is no reaction force due to the thermal expansion of the heat transfer tube 36, so that the strain generated in the lower tube sheet 35 and the upper tube sheet 34 is reduced.

Since the upper end side of the heat transfer tube 36 is suspended and supported by the upper tube sheet 34, it is sufficient to allow the heat transfer tube 36 to expand downward due to thermal expansion, and the sliding portion 38 stabilizes the heat transfer tube 36. You will be able to support your posture. In this respect, it is advantageous in comparison with the embodiment of FIGS.

Although the countercurrent heat exchanger has been described above, the heat exchanger according to the present invention is not limited to the countercurrent, and may be realized in parallel.

FIG. 7 shows an example of the co-flow heat exchanger 3.
The exhaust gas C flows in from below and flows upward, and the combustion air D also flows in from the lower part of the heat exchanger 3 and meanders toward the upper part of the heat exchanger 3 to perform heat exchange. There is. In the case of the parallel flow heat exchanger 3, in addition to the cooling by the cooling air using the cooling mechanism, the cooling effect by the combustion air D also appears, so that the high temperature lower tube sheet 35 can be effectively cooled. become able to.

It is also possible to configure the heat exchanger by appropriately combining the respective aspects described above. That is, the heat exchanger includes a tubular casing having an inflow portion and an outflow portion for combustion air, an upper tube sheet and a lower tube sheet fixed to upper and lower ends of the tubular casing, and an upper tube sheet. And a plurality of heat transfer tubes which are supported by the lower tube sheet and are vertically arranged in a cylindrical casing and through which exhaust gas flows, one end of the heat transfer tube being either the upper tube sheet or the lower tube sheet. The guide tube is fixed to the guide tube by a sliding portion that can be inserted or inserted, and the other end of the heat transfer tube is fixedly supported by either the upper tube plate or the lower tube plate.

The partition tube plate is formed inside the tubular casing so as to face the exhaust gas inflow side tube sheet of the upper tube sheet or the lower tube sheet, so that a gap is formed with respect to the tubular casing or the heat transfer tube. It is preferable that a cooling space, which is arranged and to which cooling air is supplied, be formed between the tube sheet and the partition tube sheet.

In addition, the partition tube plate is formed inside the cylindrical casing so as to face the tube plate having the sliding portion of the upper tube plate or the lower tube plate so that a gap is formed with respect to the cylindrical casing or the heat transfer tube. Is preferably provided, and a cooling space to which cooling air is supplied is formed between the tube sheet and the partition tube sheet.

When the exhaust gas pressure is P1, the combustion air pressure is P2, and the cooling air pressure is P3, P1<P2<P3 is preferably set. If at least the relationship of P1<P2<P3 is established among the pressure P1 of the exhaust gas, the pressure P2 of the combustion air and the pressure P3 of the cooling air, the cooling air supplied to the cooling space is retained. Instead, it merges with the combustion air serving as the heat receiving side fluid through the gap between the tubular casing and the partition tube sheet or the gap between the heat transfer tube and the partition tube sheet, or is transferred through the guide tube that constitutes the sliding portion. As a result, the heat can be reliably introduced into the heat pipe, and a sufficient cooling effect can be obtained even with a small amount of cooling air.

It should be noted that the pressure relationship may be set so that at least the cooling air supplied to the cooling space 44 mixes with the combustion air side or the exhaust gas side and flows, and the relationship of P1<P2<P3 is necessarily established. There is not.

As described above, since it is not necessary to form a special flow path for flowing the cooling air supplied to the cooling space 44 in the central portion of the partition tube plate 49, the heat transfer tube 36 is sealed inside the tubular casing 39. Therefore, it is possible to realize the heat exchanger 3 which can be arranged in a high temperature and has a high heat exchange efficiency and can preheat the combustion air to a high temperature range.

The above-described embodiment can employ the same configuration for both the heat exchanger 3 on the upstream side of the flue and the heat exchange 5 on the downstream side shown in FIG. 11.

Further, another embodiment of the heat exchanger of the present invention will be described. In the above-described embodiment, the cooling mechanism is provided on the high temperature tube sheet side, but the cooling mechanism may not be provided. That is, one end of the heat transfer tube 36 is supported by a guide tube 37 fixed to either the upper tube plate 34 or the lower tube plate 35 by a sliding portion 38 that can be inserted or inserted, and the heat transfer tube 36 is also attached. The other end may be fixedly supported on either the upper tube sheet 34 or the lower tube sheet 35.

For example, as shown in FIG. 8A, a sliding portion 38 is provided on the upper tube sheet 34, the exhaust gas C flows in from the upper tube sheet 34 side, and the combustion air D flows in from the lower tube sheet 35 side. It may be a countercurrent heat exchanger. Because of the counterflow, the temperature difference between the exhaust gas C and the combustion air D at the inlet and outlet is large, and a large heat load is applied to the upper tube sheet 34. Therefore, the sliding portion 38 is arranged on the upper tube sheet 34 side. Further, as shown in FIG. 8B, a sliding portion 38 is provided on the lower tube sheet 35, the exhaust gas C flows in from the upper tube sheet 34 side, and the combustion air D flows in from the upper tube sheet 34 side. The heat exchanger 3 may be a parallel flow. The upper tube sheet 34 into which the high temperature side exhaust gas C flows is welded to the heat transfer tube 36, but the heat load on the upper tube sheet 34 is eased by allowing the low temperature side combustion air D to flow in.

Since the sliding portion 38 is provided, the heat transfer tube 36 that thermally expands slides on the guide tube 37, and the reaction force due to the thermal expansion of the heat transfer tube 36 does not directly act on each tube sheet. ..

Further, as shown in FIG. 9A, a sliding portion 38 is provided on the upper tube sheet 34, the exhaust gas C flows in from the lower tube sheet 35 side, and the combustion air D flows in from the lower tube sheet 35 side. The heat exchanger 3 may be a parallel flow. The lower tube sheet 35 into which the high temperature side exhaust gas C flows is welded to the heat transfer tube 36, but the heat load on the lower tube sheet 35 is relaxed by allowing the low temperature side combustion air D to flow in. Further, as shown in FIG. 9B, a sliding portion 38 is provided on the lower tube sheet 35, the exhaust gas C flows in from the lower tube sheet 35 side, and the combustion air D flows in from the upper tube sheet 34 side. It may be a countercurrent heat exchanger 3. Since the exhaust gas C and the combustion air D have a large difference in temperature at the inlet and outlet due to the counterflow and a large heat load is applied to the lower tube sheet 35, the sliding portion 38 is arranged on the lower tube sheet 35 side. The effect that the reaction force due to the thermal expansion of the heat transfer tube 36 does not directly act on each tube sheet by the sliding portion 38 is the same as in the other embodiment.

Further, as shown in FIG. 10A, the sliding portion 38 is provided on the upper tube sheet 34, the exhaust gas C flows in from the lower tube sheet 35 side, and the combustion air D flows in from the upper tube sheet 34 side. It may be a countercurrent heat exchanger 3. Further, as shown in FIG. 10B, a sliding portion 38 is provided in the lower tube sheet 35, the exhaust gas C flows in from the upper tube sheet 34 side, and the combustion air D flows in from the lower tube sheet 35 side. It may be a countercurrent heat exchanger 3.

However, since it is on the inlet side of the high temperature exhaust gas C and on the outlet side of the high temperature side combustion air D, in the embodiment as shown in FIG. In the embodiment as shown in (1), a large heat load is applied to the upper tube sheet 34. Therefore, in the case of such an embodiment, it is preferable to provide a cooling mechanism on the tube sheet side to which a large heat load is applied.

That is, the cooling mechanism of the present invention faces the tube plate on the inflow side of the exhaust gas C of the upper tube sheet 34 or the lower tube sheet 35, inside the tubular casing 39, and with respect to the tubular casing 39 or the heat transfer tube 36. It suffices that the partition tube plate is arranged so as to form a gap, and a cooling space to which cooling air is supplied is formed between the tube plate and the partition tube plate.

According to the waste treatment facility configured as described above, it is possible to reduce the risk of damage to structural members such as the tube sheet due to the heat load, while increasing the efficiency of recovering exhaust heat to save energy. .. Although the heat transfer tube 36 and the like are fixed by welding in the above-described embodiment, the structure is not limited to welding but may be fixed and supported. Further, the heat transfer tube 36 may not be in a completely vertical posture but may be slightly inclined with respect to the vertical direction.

FIG. 11 shows another example of the waste treatment facility 1 in which the heat exchanger adopting any of the above-mentioned structures is incorporated. The waste treatment facility 1 includes a sludge storage tank 20 in which sludge is stored, a sludge charging mechanism 21, a fluidized bed incinerator 2, an exhaust gas treatment facility, and the like.

The fluidized bed incinerator 2 throws the sludge supplied from the sludge feeding mechanism 21 into the fluidized bed formed by the high temperature air supplied from the air feeding mechanism A and heats the sludge gasified to the freeboard section. It is a processing furnace that burns at. Reference numeral 14a is a temperature rising burner that heats the inside of the furnace at startup, and after the temperature of the furnace is raised, an auxiliary burner 14b is used to supplement the amount of heat required for combustion to operate the furnace.

Along the flue of the fluidized bed incinerator 2, two heat exchangers 3, 5 that preheat combustion air by the heat of the exhaust gas, a dust collector 9 that collects soot and dust, and an exhaust gas that sprays an alkaline agent. A flue gas treatment tower 10 and the like for neutralizing the acidic gas components therein are sequentially arranged.

An induction blower 11 for maintaining a negative pressure in the furnace is provided on the downstream side of the smoke exhaust treatment tower 10, and the exhaust gas attracted by the induction blower 11 is exhausted from the chimney 12.

The air supply mechanism A includes a forced air blower 6, a supercharger 4 including a turbine 4a and a compressor 4b, and heat exchangers 3 and 5. The combustion air pre-compressed by the forced air blower 6 is supplied to the air supply port of the compressor 4b, and the air compressed by the compressor 4b is preheated by the heat exchanger 5 on the downstream side and then supplied to the turbine 4a. The compressed air exhausted from is further preheated by the heat exchanger 3 on the upstream side and then supplied to the fluidized bed incinerator 2.

The air compressed by the compressor 4b is heat-exchanged with the exhaust gas at 700 to 1000° C. by the heat exchanger 5 to be preheated at 500 to 750° C. and then supplied to the turbine 4a.

By supplying the compressed air preheated by the heat exchanger 5 to the turbine 4a, the turbine 4a is rotationally driven, and the compressor 4b connected to the drive shaft is also driven. The compressed air of 400 to 650° C. discharged from the turbine 4a is further preheated to 500 to 700° C. by the heat exchanger 3 and then supplied to the fluidized bed incinerator 2 as fluidizing air, that is, combustion air to be fluidized bed. Is formed.

Since the hot combustion air discharged from the turbine 4a is further heated by the heat exchanger 3 and supplied to the fluidized bed incinerator, the amount of fossil fuel burned by the auxiliary burner 14b is reduced. Become. If the material to be burned is organic sludge, it becomes possible to burn itself without using fossil fuel.

If a higher temperature exhaust gas is introduced to raise the temperature of the combustion air, an extremely large heat load will be applied to the heat exchangers 3, 5. This is particularly noticeable in the heat exchanger 3. As such heat exchangers 3 and 5, the heat exchanger having the above-described structure can be preferably used, and while reducing the risk of damage to structural members such as the tube sheet due to thermal stress, It is possible to realize a waste treatment facility that can improve the efficiency of collecting waste heat and save energy.

Although the above-mentioned embodiment explained the case where fluidized bed type incinerator 2 was adopted as a heat treatment furnace, the incinerator to which the present invention is applied is not limited to fluidized bed type incinerator 2 and fluidized bed type incinerator 2 is used. Similarly, it can be applied to other types of industrial furnaces such as a shaft furnace having a large ventilation pressure loss. For example, a coke bed is formed in the bottom part, and a heat treatment furnace or scrap is put into the coke bed to melt the sludge from above the shaft furnace where the tuyere for supplying combustion air is formed. The present invention can be applied to a cupola or the like.

The above-described embodiments are all examples of the present invention, and the present invention is not limited to the description, and the respective embodiments may be appropriately combined. Further, it goes without saying that the specific configuration of each part can be appropriately modified and designed within the range in which the effects of the present invention are exhibited.

1: Waste treatment facility 2: Fluidized bed type incinerator 3, 5: Heat exchanger 4: Supercharger 4a: Turbine 4b: Compressor 6: Push blower 9: Dust collector 10: Smoke treatment tower 11: Induction blower 12: Chimney 14a: Temperature rising burner 14b: Auxiliary burner 20: Sludge storage tank 21: Sludge charging mechanism 30, 31: Combustion air inflow part 32: Combustion air outflow part 33: Jacket part 34: Upper tube sheet 35: Lower part Tube plate 36: Heat transfer tube 37: Guide tube 38: Sliding part 39: Cylindrical casing 40: Baffle plate 41: Air flow path 42: Cooling air inflow part 43: Combustion air outflow part 44: Cooling space 45: Exhaust gas flow Inlet 46: Exhaust gas outlet 47: Inflow header part 48: Outflow header part 49: Partition tube plate 50: Combustion air inflow part A: Air supply mechanism C: Exhaust gas D: Combustion air

Claims (7)

A waste treatment facility comprising a heat treatment furnace and a heat exchanger installed in a flue of the heat treatment furnace to preheat combustion air of the heat treatment furnace by heat retained by exhaust gas,
The heat exchanger includes a casing having an inlet and an outlet for combustion air, an upper tube sheet and a lower tube sheet fixed to upper and lower ends of the casing, the upper tube sheet and the lower tube sheet, respectively. A plurality of heat transfer tubes supported by a tube plate and arranged in the casing, through which exhaust gas flows, and
One end of the heat transfer tube slides with a guide tube fixed to one of the upper tube plate or the lower tube plate, and the other end of the heat transfer tube has an upper tube plate or a lower tube plate. Fixedly supported on either side,
Of the upper tube plate or the lower tube plate, facing the tube plate on the exhaust gas inflow side, inside the casing, is fixed only to the heat transfer tube and moves relative to the tubular casing integrally with the heat transfer tube. A possible partition tube plate is arranged, a cooling space is configured between the tube plate and the partition tube plate,
The cooling air supplied to the cooling space flows out from a gap formed between the outer peripheral portion of the partition tube plate and the inner wall surface of the cylindrical casing facing the outer peripheral portion, and burns in the casing. A waste treatment facility that is configured to be mixed into commercial air.
A waste treatment facility comprising a heat treatment furnace and a heat exchanger installed in a flue of the heat treatment furnace to preheat combustion air of the heat treatment furnace by heat retained by exhaust gas,
The heat exchanger includes a casing having an inlet and an outlet for combustion air, an upper tube sheet and a lower tube sheet fixed to upper and lower ends of the casing, the upper tube sheet and the lower tube sheet, respectively. A plurality of heat transfer tubes supported by a tube plate and arranged in the casing, through which exhaust gas flows, and
One end of the heat transfer tube slides with a guide tube fixed to one of the upper tube plate or the lower tube plate, and the other end of the heat transfer tube has an upper tube plate or a lower tube plate. Fixedly supported on either side,
The upper tube plate or the lower tube plate is opposed to a tube plate provided with the guide tube, and is fixed inside the casing only to the heat transfer tube and integrally with the heat transfer tube relative to the tubular casing. A movable partition tube plate is arranged, a cooling space is configured between the tube plate and the partition tube plate,
The cooling air supplied to the cooling space flows out from a gap formed between the outer peripheral portion of the partition tube plate and the inner wall surface of the cylindrical casing facing the outer peripheral portion, and burns in the casing. A waste treatment facility that is configured to be mixed into commercial air.
The waste treatment facility according to claim 1 or 2, wherein the guide tube is configured so that the heat transfer tube can be inserted or inserted therein. The waste treatment facility according to any one of claims 1 to 3, wherein the casing has a substantially vertical tubular shape, and the heat transfer tubes are arranged in an axial direction of the casing. The waste treatment facility according to any one of claims 1 to 4 , wherein the guide tube is provided on a tube plate on the exhaust gas inflow side of the upper tube plate or the lower tube plate. The guide tube is provided on the outflow side of the tube plate of the exhaust gas of the upper tube sheet or the lower tube plate, the inlet of the combustion air to any of claims 1 is provided on the inflow side of exhaust gas 4 Waste treatment facility described in Crab. The discard according to any one of claims 1 to 6 , wherein P1<P2<P3 is set when the pressure of the exhaust gas is P1, the pressure of the combustion air is P2, and the pressure of the cooling air is P3. Material processing equipment.

Images