JP4721723B2 - Temperature reduction tower for exhaust gas treatment - Google Patents

Description

  The present invention relates to a temperature reduction tower for exhaust gas treatment for reducing the temperature of exhaust gas from municipal waste incinerators and melting furnaces by water spray.

  Conventionally, exhaust gas generated in municipal waste incinerators, melting furnaces, etc. is exhaust gas temperature reduced by moving the inside of the cylindrical tower from the top to the bottom of the tower and spraying cooling water during this time to exchange heat and cooling the gas. It is processed in the tower and sent to the next step.

  In this temperature reduction tower for exhaust gas treatment, it is necessary to effectively reduce the temperature by avoiding obstacles caused by dust accompanying the exhaust gas sent from municipal waste incinerators and melting furnaces adhering to the tower inner walls and ducts. is there. However, when the exhaust gas is introduced into the temperature-decreasing tower and flows down in the tower, the gas flow changes direction while the exhaust gas is guided to the top of the temperature-decreasing tower by the introduction duct, resulting in drift and contact with the cooling water. There are problems that the efficiency is low and that dust accompanying the contact with the inner wall of the tower adheres to the wall surface when it flows down in the tower and easily causes a failure. Therefore, it is necessary to rectify the flow of exhaust gas in the tower.

  For this reason, as a means for solving this problem, an exhaust gas inlet is provided at the top of the tower for rectification at the exhaust gas inlet to the temperature reducing tower, and a part of the exhaust gas inlet duct is curved with respect to the inlet. Patent Document 1 discloses an attempt to obtain a rectifying effect. Patent Document 2 discloses a configuration in which a gas introduction structure portion having a complicated partition structure is attached to an exhaust gas introduction port at the top of the tower, and an exhaust gas introduction duct is connected via the gas introduction structure portion. Are known.

  In addition, as shown in FIG. 6, the present inventors erect an introduction cylinder portion 102 communicating with the exhaust gas introduction duct 103 at the top of the tower body 101 of the temperature reducing tower 100, and It connects with the tower body 101 top end of the temperature-reduction tower 100 through the taper cylinder part 104 which spreads from the lower end to the bottom, and it is set as the structure which arrange | positions the taper cylinder type rectification | straightening plate 105 (rectifier cylinder) inside the said taper cylinder part 104. It was found that the exhaust gas to be introduced can be caused to flow down in a rectified state in the tower body 101 by adopting a method in which the exhaust gas introduced in this way flows vertically into the temperature reducing tower 100. Reference numeral 107 in the figure denotes a cooling water spray nozzle.

Japanese Patent No. 3537292 JP 2004-113955 A

  It is recognized that the prior art disclosed in Patent Document 1 is theoretically effective. However, in this type of system, it is necessary to form a large conduction path bent at a center of curvature of 180 ° or more as a rectifying unit connected to the introduction duct and connect it to the top of the temperature reducing tower. As the number increases, the overall structure becomes large and the installation equipment becomes expensive. In addition, since the installation height is high due to the configuration, a building for installing the temperature reducing tower is required to be tall, and there is a problem that the construction cost increases accordingly.

  Further, in the apparatus disclosed in Patent Document 2, the gas introduction structure installed at the top of the gas processing tower (temperature reduction tower) has a structural and complicated structure in which partitions are arranged vertically and horizontally. Therefore, when dust is accompanied with the introduced exhaust gas, the dust tends to deposit on the shelf-like portion generated by the partition portion. In addition, when dust accumulates, there is a problem in that the removal operation requires a lot of labor and is inconvenient. In addition, this gas introduction structure has a structure in which the gas outlet with respect to the exhaust gas inlet of the gas treatment tower is offset, so even if the drift is eliminated in the gas introduction structure, the drift occurs again in the gas treatment tower. There is a problem that the structure becomes easy to do.

  On the other hand, in the rectifier of the type shown in FIG. 6, the exhaust gas introduced into the tower body 101 of the temperature-decreasing tower 100 can be rectified by sending it vertically toward the top 106 of the tower. It is necessary to lengthen the cylinder part 102. Therefore, if this method is adopted, the overall height of the temperature-decreasing tower is increased, so that the building for installing the temperature-decreasing tower must also be increased, and there is a problem in its economic efficiency.

  The present invention has been made to solve these problems, and the structure of the exhaust gas introduction section to the temperature reduction tower is improved by a simple rectification structure to enhance the rectification function, and the temperature reduction treatment by cooling water spray is made effective. An object of the present invention is to provide a temperature reducing tower for exhaust gas treatment.

In order to achieve the above-mentioned object, the exhaust gas treatment temperature reducing tower of the present invention comprises:
In the dehumidifying treatment temperature reducing tower, the exhaust gas to be treated is introduced from the top of the tower body, the exhaust gas is cooled by spraying cooling water during the flow in the tower, and discharged from the lower part of the tower.
Inside the cylindrical exhaust gas receiving chamber provided directly connected to the exhaust gas inlet at the top of the tower body, a cylindrical upper half part that forms a circular space around the concentric circle, and a lower edge is the inner surface of the exhaust gas receiving chamber And a lower half portion having a tapered diameter formed so as to have a smaller gap than the other portions, and the exhaust gas introducing duct is arranged so as to be orthogonal to the central axis of the rectifying tube. The exhaust gas receiving chamber is connected to face the upper half of the flow straightening cylinder (first invention).

  In the above invention, the exhaust gas receiving chamber has a smaller diameter than the straight body portion of the temperature-decreasing tower body, and a tapered body portion that extends downward from the exhaust gas inlet to which the exhaust gas receiving chamber is attached to the straight body portion of the temperature-decreasing tower body. (2nd invention).

  In the present invention, the exhaust gas introduction duct is preferably connected to the exhaust gas receiving chamber at an angle of 50 ° or less with respect to an axis passing through the center thereof (third invention). Further, the exhaust gas introduction duct is preferably connected to the exhaust gas receiving chamber so that the gas outlet thereof is located at a position facing the outer surface of the upper half of the flow straightening cylinder (fourth invention).

  In the present invention, the exhaust gas receiving chamber and the upper end portion of the rectifying cylinder are arranged at a predetermined interval so that the gas flowing in from the gas outlet of the exhaust gas introducing duct can be dispersedly introduced into the rectifying cylinder. (5th invention).

  In the present invention, when the exhaust gas introduced into the tower body of the temperature reducing tower is given flow resistance before the exhaust gas inlet to cause an appropriate pressure loss, the flow straightening tubes are concentrically arranged in the exhaust gas receiving chamber. In addition, an annular narrow gap is formed at the lower end of the outer periphery so that the gas flow into the tower is faster in the periphery than the center, and the entire flow is made to flow in the center of the tower body, Are dispersed. As a result, the exhaust gas inlet provided at the top of the tower can be dispersed and introduced from the central part of the tower to be in a rectified state, and the structure can be simplified and the effectiveness can be enhanced.

  According to the present invention, since the exhaust gas introduction rectification structure can be easily and compactly integrated, dust accumulation in the rectification structure part (exhaust gas receiving chamber and rectification cylinder) can be prevented, and long-term operation can be achieved. Enable. In addition, the overall structure can be reduced in volume and the rectification state can be improved, so that the water spray position is provided closer to the exhaust gas inlet than in the conventional temperature reduction tower, so that the height of the temperature reduction tower is reduced. Is possible. Therefore, not only the apparatus itself but also the installation building can be lowered, and the installation cost can be reduced.

  Further, by connecting the exhaust gas introduction duct to the gas inlet of the exhaust gas receiving chamber at a more acute angle, dust accumulation can be prevented and the height structure of the rectifying structure is reduced. In addition, by providing a flow straightening tube with a tapered tube portion in the flow straightening structure and making it a composite tube shape, the rectified exhaust gas flows down in the center of the temperature reducing tower, and the occurrence of drift is prevented. Therefore, it is possible to effectively prevent dust and the like from adhering to the inner wall of the tower.

  Next, a specific embodiment of a temperature reducing tower for exhaust gas treatment according to the present invention will be described with reference to the drawings.

  FIG. 1 is an overall schematic diagram of an exhaust gas treatment desuperheating tower according to the present embodiment, FIG. 2 is a schematic perspective view showing the main part of the exhaust gas desuperheating tower, and FIG. 3 is a longitudinal sectional view of the main part. (A) and plan view (b) are shown respectively.

  In the temperature reduction tower 1 for exhaust gas treatment of the present embodiment, an exhaust gas inlet 3 is provided at the top of the generally cylindrical tower body 2 and a treated gas outlet 4 is provided at the bottom. An exhaust gas receiving chamber 5 in which a flow straightening cylinder 6 is disposed is directly connected to the upper part of the exhaust gas inlet 3, and an exhaust gas introduction duct 10 generated in, for example, a municipal waste incinerator is connected to the exhaust gas receiving chamber 5. It is comprised so that. The exhaust gas inlet 3 provided at the upper top of the tower body 2 and the straight body portion of the tower body 2 are connected by a taper body portion 2 'that extends downward.

  The exhaust gas receiving chamber 5 has a cylindrical shape corresponding to the diameter of the exhaust gas inlet 3 (in this embodiment, a cylindrical shape corresponding to the tower body 2), and the top is covered with a top plate 5a. . Inside the exhaust gas receiving chamber 5, a rectifying cylinder 6 is disposed concentrically. The rectifying cylinder 6 is provided so as to be positioned coaxially by a plurality of support members (not shown) having base ends attached to the inner wall surface of the exhaust gas receiving chamber 5.

  The flow straightening cylinder 6 has an upper half 6a formed in a cylindrical shape, and a lower half 6b formed in a taper cylinder extending downward to form an integral structure. Therefore, an annular space 20 is formed between the outer peripheral surface of the upper half 6 a of the flow straightening cylinder 6 and the inner peripheral surface of the exhaust gas receiving chamber 5. Further, an annular gap 30 is formed between the lower edge 6c of the lower half 6b and the inner wall surface of the exhaust gas receiving chamber 5 so that dust flowing in along with the exhaust gas can fall without being deposited. In addition, the taper surface of the lower half part 6b is made into the shape which can ensure the angle of repose with respect to dust (for example, inclination angle of about 20 degrees with respect to an axial center).

  Further, the upper edge 6a 'of the upper half 6a of the flow straightening cylinder 6 and the top plate 5a of the exhaust gas receiving chamber 5 are arranged so that the exhaust gas flowing from the exhaust gas introduction duct 10 is dispersed in contact with the flow straightening cylinder 6, It arrange | positions so that the gap | interval 40 which makes the state which can flow in into the inside of the rectification | straightening cylinder 6 will be obtained.

  On the other hand, the gas inlet 8 for introducing the exhaust gas into the temperature reducing tower 1 is provided so as to face the outer peripheral surface of the upper half 6a of the flow straightening cylinder 6 in the exhaust gas receiving chamber 5. The exhaust gas introduction duct 10 connected to the gas inlet 8 is connected to the axis C of the exhaust gas receiving chamber 5 at an angle of 50 ° or less. In this way, the exhaust gas introduction duct 10 is sent together with the gas without the accompanying dust being deposited and deposited in the introduction duct 10. Therefore, it is preferable to make the attachment inclination angle of the exhaust gas introduction duct 10 to the gas inlet 8 more acute if possible in the installation conditions. In addition, if the mounting angle of the exhaust gas introduction duct 10 with respect to the gas inlet 8 exceeds 50 ° and approaches a horizontal state, it is not preferable because a dust deposition phenomenon tends to occur.

  Inside the tower body 2 to which the exhaust gas receiving chamber 5 directly connected as described above is connected, the exhaust gas rectified by the rectifying cylinder 6 and the exhaust gas receiving chamber 5 flows down from the exhaust gas inlet 3 into the tower body 2. The cooling water spray nozzle 15 is arranged at the upper position. Cooling water is supplied to the spray nozzle 15 from the outside of the tower body 2 through a cooling water supply pipe 16, and the cooling water is sprayed onto the flowing exhaust gas to cool it.

  In the exhaust gas treatment temperature reducing tower 1 of the present embodiment configured as described above, the introduced exhaust gas is rectified and reduced in temperature as follows.

  When exhaust gas is sent into the interior from the gas inlet 8 of the exhaust gas receiving chamber 5 provided at the top of the temperature reducing tower 1 by the introduction duct 10, when the exhaust gas flows out from the gas inlet 8 first, It collides with the outer peripheral surface of the half 6a and flows in at least two directions along the peripheral surface. In addition to this, in the gas flow dispersed in the vertical direction, the rising exhaust gas is changed in the flow direction by the top plate 5 a portion of the exhaust gas receiving chamber 5 and flows into the rectifying cylinder 6. Further, the flow of the exhaust gas flowing and descending along the outer peripheral surface of the rectifying cylinder 6 flows toward the lower gap 30 along the tapered surface of the lower half 6 b of the rectifying cylinder 6.

  As soon as the exhaust gas flowing in this way is discharged into the inside from the gas inlet 8, the flow direction is changed by contacting the outer peripheral surface of the rectifying cylinder 6, and then between the rectifying cylinder 6 and the inner surface of the exhaust gas receiving chamber 5. By moving the annular space 20 formed in the flow, a flow resistance is added and the speed is reduced. The flow descending from the annular space 20 along the taper surface is greatly affected by the orifice effect at the annular gap 30 portion along the lower end edge 6c of the lower half 6b of the rectifying cylinder 6. The partial gas flow flows to the space 40 side formed above the rectifying cylinder 6. The exhaust gas reaching the space 40 changes its direction by contacting the inner surface of the top plate 5a at that portion, and is caused to flow into the inner space of the rectifying cylinder 6. In the inner space portion of the rectifying cylinder 6, the gas flows in the same direction inward from the periphery of the upper edge 6a 'of the rectifying cylinder 6, so that a resistance is given at this inlet, and the gas is decelerated as it is. It will flow down toward the inflow port 3.

  On the other hand, the gas flow moving downward along the outer periphery of the rectifying cylinder 6 is converted into gas energy by converting pressure energy into velocity energy due to a pressure difference between the annular space 20 and the gas inlet 3 side at the lower annular gap 30 portion. It is ejected from the inlet 3 into the tower body 2. Therefore, most of the gas flow flowing down from the inside of the rectifying cylinder 6 flows down in a state surrounded by a gas flow having a high flow velocity ejected from the annular gap 30 portion.

  As a result, the exhaust gas flowing into the tower body 2 through the annular gap 30 and the inside of the rectifying cylinder 6 is sent to the part surrounding the axial center of the tower body 2, in other words, the periphery surrounding the inner center of the tower body 2. As a result, the gas flows into the tower body 2 without causing a drift, and moves to the straight body portion having a larger area than the exhaust gas receiving chamber 5 through the tapered body portion 2 '. It will flow down the body.

  The exhaust gas flowing into the tower main body 2 in the rectified state in this way is contacted with the spray cooling water ejected from the spray nozzle 15 provided at the upper position of the straight body portion to be heat-exchanged and cooled to cool the lower part of the tower main body 2. The gas is discharged from the gas outlet 4 to the next processing step through a conduit. Then, the exhaust gas is rectified and flows in the tower, so that the spray water droplets of the cooling water stay in the tower for an appropriate time, improve heat exchange with the exhaust gas, and completely evaporate. Therefore, it does not adhere to the inner wall of the tower, and it is possible to avoid the occurrence of wall corrosion.

  Since the exhaust gas flowing into the tower body 2 flows in a rectified state as described above, naturally no drift occurs, so that accompanying dust is also prevented from adhering to the inner wall of the tower. Also, since the exhaust gas is rectified and flows in the tower, the entrained dust that is agglomerated by the spray cooling water can fall to the lower part of the tower as it is and can be easily collected, and is attached to the wall surface. It is possible to avoid deposition.

  Incidentally, in order to verify the rectification of the exhaust gas to be treated for the exhaust gas treatment temperature-decreasing tower 1 of the present embodiment, the tower including the exhaust gas receiving chamber 5 and the rectifying cylinder 6 described above is used. The velocity distribution of the gas flow in the main body 2 was confirmed. This is shown in FIG. 4 by a front view (a) and a right side view (b) showing the velocity distribution of the gas flow in the temperature reduction tower for exhaust gas treatment.

  According to this velocity distribution chart, when the exhaust gas flows into the tower body 2 from the exhaust gas inlet 3 through the exhaust gas receiving chamber 5, it can be confirmed that the exhaust gas quickly enters a rectified state and flows down in the tower. In addition, what appears in stripes in multiple stages in the vertical direction in the tower body 2 indicates the velocity distribution at each position.

  Moreover, the rectification | straightening state in the temperature-reduction tower 1 for exhaust gas treatment of the said embodiment is shown by the front view (a) and side view (b) which show the locus | trajectory of the water particle by spraying of the cooling water in the said temperature-reduction tower in FIG. The water particles of the spray cooling water against the exhaust gas flowing in (the solid line appearing in the portion corresponding to the axial center line of the tower body in the figure is the trajectory of the water particles) are surely heat-exchanged and evaporated to enhance the cooling effect I can confirm that I can. That is, it can be seen that the water droplets (water particles) have evaporated before reaching the intermediate position of the tower body, which indicates that the cooling effect is high.

  Although the above-described temperature reduction tower for exhaust gas treatment has been described with respect to a cylindrical shape, it is not limited to a cylindrical shape in accordance with the gist of the present invention, and may be a polygon as necessary. is there.

Overall schematic diagram of the temperature reduction tower for exhaust gas treatment of this embodiment Schematic perspective view showing the main part of a temperature reducing tower for exhaust gas treatment Longitudinal section (a) and plan view (b) The front view (a) which shows the velocity distribution of the gas flow in the temperature-reduction tower for exhaust gas treatment of this embodiment, and the right view (b) The front view (a) and side view (b) which show the locus of the water particle by spraying of the cooling water in the temperature reducing tower for exhaust gas treatment of this embodiment Schematic diagram of the rectifier of the cooling tower for exhaust gas treatment, which was examined earlier

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Temperature-reduction tower for exhaust gas treatment 2 Tower main body 3 Exhaust gas inlet 5 Exhaust gas receiving chamber 6 Rectification cylinder 6a Upper half part of a rectification cylinder 6b Lower half part of a rectification cylinder 8 Gas inlet 10 Exhaust gas introduction duct 15 Cooling water spray nozzle 20 Annular space 30 in the exhaust gas receiving chamber 30 Annular gap in the exhaust gas receiving chamber 40 A space above the rectifying cylinder

Claims (5)

In the dehumidifying treatment temperature reducing tower, the exhaust gas to be treated is introduced from the top of the tower body, the exhaust gas is cooled by spraying cooling water during the flow in the tower, and discharged from the lower part of the tower.
Inside the cylindrical exhaust gas receiving chamber provided directly connected to the exhaust gas inlet at the top of the tower body, a cylindrical upper half part that forms a circular space around the concentric circle, and a lower edge is the inner surface of the exhaust gas receiving chamber And a lower half portion having a tapered diameter formed so as to have a smaller gap than the other portions, and the exhaust gas introducing duct is arranged so as to be orthogonal to the central axis of the rectifying tube. A temperature reducing tower for exhaust gas treatment, which is connected to an exhaust gas receiving chamber so as to face the upper half of the flow straightening cylinder.   The exhaust gas receiving chamber is smaller in diameter than the straight body portion of the temperature reducing tower body, and is connected by a taper body portion extending from the exhaust gas inlet to which the exhaust gas receiving chamber is attached to the straight body portion of the temperature reducing tower body. The temperature-decreasing tower for exhaust gas treatment according to claim 1.   The temperature reduction tower for exhaust gas treatment according to claim 1, wherein the exhaust gas introduction duct is connected to the exhaust gas receiving chamber at an angle of 50 ° or less with respect to an axis passing through the center thereof.   4. The exhaust gas treatment temperature-decreasing tower according to claim 1, wherein the exhaust gas introduction duct is connected to the exhaust gas receiving chamber so that a gas outlet thereof is positioned just opposite to an outer surface of the upper half of the flow straightening cylinder. .   2. The exhaust gas receiving chamber and the upper end portion of the flow straightening cylinder are arranged at a predetermined interval so that gas flowing from the gas outlet of the exhaust gas introduction duct can flow inwardly into the flow straightening cylinder. 2. A temperature reducing tower for treating exhaust gas according to 1.

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