JP3929247B2 - Combustion furnace integrated gas cooling tower - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas cooling tower for reducing the temperature of high-temperature exhaust gas to a predetermined temperature, and more particularly to a combustion furnace integrated gas cooling tower that rectifies the flow of gas sent to the cooling tower so that it can be efficiently cooled. Is.
[0002]
[Prior art]
Conventionally, in facilities such as waste incinerators and ash melting furnaces, gas including unburned gas (CO, HC, etc.) is completely burned in the combustion furnace, and then the high-temperature exhaust gas is guided to the gas cooling tower to reduce the temperature. It is sent to an exhaust gas treatment device such as a filter to remove suspended dust and diffused into the atmosphere.
[0003]
In general, in a gas cooling tower, the cooling water is sprayed and gas-liquid contact is made so that the gas temperature at the outlet of the cooling tower becomes a predetermined temperature (allowable temperature sent to an exhaust gas treatment device such as a bag filter, for example, around 200 ° C.). The gas temperature is lowered by the cooling means. By the way, in the combustion furnace integrated type gas cooling tower 100 as shown in FIG. 4A, exhaust gas is directly introduced into the lower part of the cooling tower 100 from the outlet of the gas secondary combustion furnace 104, and the inside of the tower is gas outlet. In this method, the temperature of the gas is decreased by spraying cooling water from the cooling water nozzle 102 while the temperature rises to 101. Further, in the separate gas cooling tower 110 shown in FIG. 4B, the exhaust gas is guided from the secondary combustion furnace 114 to the exhaust gas inlet 111 at the upper part of the cooling tower 110 by the duct 115 and flows into the cooling tower 110. In this method, the water is allowed to flow downward, and is cooled by spraying cooling water from the upper part by the cooling water nozzle 113 while being sent out from the lower part of the tower by the gas discharge pipe 112.
[0004]
[Problems to be solved by the invention]
However, in these methods, when the exhaust gas is introduced into the cooling tower, the flow of the gas flowing into the gas cooling tower is biased, which causes dust adhesion and accumulation in the cooling tower, and the gas is uniformly distributed. There is a problem that it is not cooled. In particular, if dust adheres or accumulates in the tower, a large expense is generated for the removal treatment, which greatly affects the operation cost.
[0005]
In addition, in the conventional gas cooling tower integrated with the combustion furnace, the gas temperature in the combustion furnace decreases due to radiation cooling between the gas cooling tower and the combustion furnace, which hinders combustion ( There is a problem that it becomes difficult to incinerate dioxins in fuel gas). Furthermore, if the cooling water does not completely evaporate due to gas drift in the cooling tower or fluctuations in the amount of exhaust gas, condensed water droplets fall into the combustion furnace, adversely affecting the combustion in the furnace. On the other hand, in the separate type gas cooling tower, a place for installing the gas cooling tower is required separately from the combustion furnace integrated type gas cooling tower.
[0006]
The present invention has been made in order to solve such problems, and prevents the adhesion and accumulation of dust contained in the gas in the gas cooling tower, and rectifies the exhaust gas to efficiently cool the combustion furnace integrated gas. The object is to provide a cooling tower.
[0007]
[Means for solving the problems and actions / effects]
In order to achieve the above-described object, a gas-cooling tower integrated with a combustion furnace according to the present invention has a plurality of ceramic porous tubes arranged so that air is ejected from the inside across the inside of the cooling tower. A gas rectifying device is provided.
[0008]
According to the present invention, the high-temperature exhaust gas from the secondary combustion furnace is led to the cooling tower, and the plurality of ceramic porous holes installed across the tower are flown up to the gas outlet through the cooling tower. The flow of gas is rectified by the gas rectifier arranged in the material pipe, and after passing through this gas rectifier, the gas can flow almost evenly. The cooling water spray generally works effectively to enhance the cooling effect. Further, by balancing the gas flow, it is possible to prevent the dust contained in the tower from adhering and accumulating, so that it is possible to omit these treatments and to increase the operation efficiency. Further, when installed directly connected to the upper part of the combustion furnace, the gas rectifier prevents radiation cooling between the cooling tower and the combustion furnace, and the effect of preventing the gas temperature in the combustion furnace from being lowered can be obtained. In addition, even if water droplets of cooling water are generated, the water droplets can be prevented from falling directly into the combustion furnace.
[0009]
In the first aspect of the invention, the gas rectifier includes a plurality of ceramic porous tubes arranged in multiple stages at a predetermined interval, and air is supplied from the outside into each ceramic porous tube and flows out of the tube. It is good to be. By doing so, the gas flows between the ceramic porous tubes arranged at a required interval, so that an appropriate resistance can be given and the flow of the gas can be rectified. The ceramic porous tube prevents air from being exposed to high temperatures by forming air film on the surface of the tube by sending air into the interior and flowing air from the voids in the porous portion. The effect that enables long-term use.
[0010]
In the first invention and the second invention, it is preferable that the plurality of ceramic porous tubes constituting the gas rectifier are provided at least vertically in a two-stage zigzag arrangement (third invention). If it carries out like this, the gas which raises from the downward | lower direction will flow, without going straight between the ceramic porous tubes arranged in multiple numbers, and can improve a rectification effect. Further, the inside of the tower is projected and divided by the plurality of ceramic porous tubes, so that radiation cooling between the cooling tower and the combustion furnace can be surely cut off.
[0011]
Furthermore, in the first to third aspects of the invention, when the plurality of ceramic porous tubes of the gas rectifier are arranged in multiple stages, the air piping to be supplied to each stage is divided into stages, It is preferable that an on-off valve is provided in the pipe so that it can be switched. In this way, the air supply to the ceramic porous tube can be selected according to the amount of gas sent to the cooling tower, the air consumption can be reduced according to the exhaust gas treatment capacity, and the running cost can be reduced. Reduction can be achieved.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, a specific embodiment of a combustion furnace integrated gas cooling tower according to the present invention will be described with reference to the drawings.
[0013]
FIG. 1 shows a schematic diagram of an ash melting processing apparatus including a combustion furnace integrated gas cooling tower according to the present invention. Further, FIG. 2 shows a schematic diagram in which a part of the gas cooling tower of the present embodiment is cut out, and FIG. 3 shows a diagram showing an arrangement form of ceramic porous tube groups in the gas rectifier.
[0014]
The gas cooling tower of this embodiment will be described mainly for use in an exhaust gas treatment process from a secondary incinerator in a melting treatment apparatus for fly ash generated in association with waste treatment / industrial waste incineration.
[0015]
In the ash melting treatment apparatus 1 shown in FIG. 1, exhaust gas containing unburned gas generated in the incineration process in the ash melting furnace 2 is exhausted by a duct 3 from a gas discharge port 2 a provided in the upper part of the ash melting furnace 2. The secondary combustion furnace 4 is sent to the secondary combustion furnace 4, and the exhaust gas containing unburned gas is subjected to secondary combustion in the secondary combustion furnace 4, and the temperature is reduced to a predetermined temperature by the cooling tower 10 provided at the upper part. Thus, the gas, which has been sent to the bag filter 6 and cleaned by removing dust, is sucked by the blower 7 and diffused from the stack 8 into the atmosphere. In the figure, reference numeral 4a denotes an air supply unit to the secondary combustion furnace, 21 denotes an ash supply device that supplies the molten fly ash A to the ash melting furnace 2, 22 denotes a supply screw, and 23 and 23 'denote ash melting furnaces. An electrode, 24 is a hot metal B discharge processing device, and 25 is a carry-out conveyor for dust captured by a bag filter.
[0016]
The cooling tower 10 provided at the top of the secondary combustion furnace 4 is configured so that the flow of exhaust gas guided from the secondary incinerator 4 to the cooling tower 10 is evenly dispersed in the tower 11 and flows up to the gas outlet 12. In addition, a gas rectifying device 15 is provided in the lower part thereof, and a spray nozzle 13 of cooling water is disposed in the middle part of the tower so as to cool the flowing exhaust gas. In the figure, reference numeral 14 is a cooling water supply pipe, and 17 is a supply air pipe.
[0017]
The gas rectifier 15 is supported on the tower wall in a state in which a plurality of ceramic porous tubes 16 are arranged in a horizontal direction at a predetermined interval and arranged in a plurality of stages to divide the inside of the tower vertically. Each ceramic porous tube 16 is closed at one end, and air is supplied from the other end to the inside by piping from the outside of the tower so that the porous body passes through and flows out from the peripheral surface of the tube. Has been. The supply air pipe 17 for each ceramic porous pipe 16 is divided into a plurality of pipes arranged in multiple layers (multistage), and a control valve 18 is provided for each of the divided pipes. By doing so, the supply of air can be controlled in accordance with the amount of exhaust gas.
[0018]
The ceramic porous tubes 16 used in this gas rectifying device 15, but heat resistant temperature of about 1400 ° C., in the driving range, 50~100mmH ₂ O, preferably such that the airflow resistance of 80~100mmH ₂ O By using a material having a porosity and a thickness (for example, an inner diameter of 40 mm, a thickness of 10 mm, and a porosity of about 30%), an air film thickness of a uniform air flow flowing out from the surface of the ceramic porous tube 16 is formed. be able to.
[0019]
Further, the arrangement of the ceramic porous tubes 16 basically gives an appropriate resistance to the exhaust gas flowing in the cooling tower 11 divided up and down by the gas rectifier 15 so that the flow is not biased. In consideration of the amount of exhaust gas and the amount of dust contained in the exhaust gas, the number of ceramic porous tubes 16 arranged per row and the number of layers arranged in multiple layers are determined. In addition, what is shown in FIG. 2 represents the outline of the arrangement, and is not limited by this number.
[0020]
Further, in order to arrange the ceramic porous tubes 16 in a multilayer (multistage) arrangement, as shown in FIG. 3, a staggered arrangement (a) in which the upper and lower arrangements are arranged shifted by a half pitch, and a vertical board in which the upper and lower arrangements are arranged. An eye arrangement (b), a grid type arrangement in which upper and lower arrangements are alternately intersected, and the like can be adopted, and further, the arrangement can be selected according to the exhaust gas to be treated. If the staggered arrangement is adopted in the above-described arrangement procedure, the inside of the tower is cut off in plan view, so that the influence of cooling radiation between the cooling tower 10 and the combustion furnace 4 can be ensured. There are advantages that can be eliminated.
[0021]
In the gas cooling tower 10 configured in this manner, since the gas rectifier 15 described above is disposed in the lower part of the tower, when the high-temperature exhaust gas generated in the secondary combustion furnace 4 is sent, the exhaust gas is gas-rectified. Since the gas flows through the narrow gap formed by the plurality of ceramic porous tubes 16 arranged in the apparatus 15 to the upper portion of the tower 11, the flow of the exhaust gas is dispersed by the flow resistance therebetween, and the flow is rectified. And flowed to the upper part of the tower. Therefore, the exhaust gas is efficiently cooled by contacting with the cooling water sprayed upward from the cooling water spray nozzle 13 provided in the middle part of the tower 11 and is cooled to a predetermined temperature. It is discharged from the gas outlet 12.
[0022]
In addition, with such a configuration, the gas cooling tower 10, the combustion furnace 4, and the space are blocked by the gas rectifier 15, so that a decrease in gas temperature in the combustion furnace 4 due to radiation cooling can be prevented. Does not cause a decrease in combustion efficiency. Moreover, even if the cooling water spray does not completely evaporate and falls as water droplets in the gas cooling tower 10, it is received by the arranged ceramic porous tubes 16 in the gas rectifier 15, Water drops are prevented from falling into the combustion furnace 4. Therefore, the combustion furnace is not affected.
[0023]
Furthermore, each ceramic porous tube 16 of the gas rectifying device 15 has an air film layer formed on the surface thereof by air supplied into the tube, thereby preventing adhesion and accumulation of dust contained in the exhaust gas. It does not hinder the exhaust gas rectification operation. In addition, since dust removal and cleaning can be omitted, there is no trouble in the work, and the effect that the long-term operation of the facility can be achieved in combination with the improvement of the cooling effect is obtained.
[0024]
Further, as described above, when the ceramic porous tubes 16 are arranged in multiple stages and air is supplied to these pipes, the air supply pipe 17 is divided for each arrangement stage and a control valve 18 is provided for each. For example, when the amount of exhaust gas to be cooled is large, air is supplied to all the pipes, and when the amount of exhaust gas is small, control is performed such as stopping the air supply to the row of pipes. This can be done, thereby reducing the amount of air consumed and lowering operating costs.
[0025]
Although the above description has described what was used for the exhaust gas treatment equipment connected to the ash melting furnace, it can also be used in a garbage incinerator in accordance with the gist of the present invention.
[Brief description of the drawings]
FIG. 1 is a schematic view of an ash melting processing apparatus including a combustion furnace integrated gas cooling tower according to the present invention.
FIG. 2 is a schematic view showing a part of the gas cooling tower of the present embodiment cut away.
FIG. 3 is a diagram showing an arrangement of ceramic porous tube groups in a gas rectifier.
FIG. 4 is a schematic diagram showing a conventional combustion furnace integrated gas cooling tower (a) and a separate gas cooling tower (b).
[Explanation of symbols]
1
2 Ash melting furnace 4 Secondary combustion furnace 6 Bag filter 10 Gas cooling tower 11 Inside the tower 12 Gas outlet 13 Cooling water spray nozzle 15 Gas rectifier 16 Ceramic porous pipe 17 Supply air pipe 18 Control valve

Claims (4)

A combustion furnace-integrated gas cooling tower comprising a gas rectifier in which a plurality of ceramic porous tubes arranged so as to blow air from inside the cooling tower are provided inside the cooling tower. 2. The gas rectifying device is configured such that a plurality of ceramic porous tubes are arranged in multiple stages at a predetermined interval, and air is supplied from the outside into each ceramic porous tube to flow out of the tubes. A combustion furnace integrated gas cooling tower as described in 1. 3. The combustion furnace integrated gas cooling tower according to claim 1, wherein the plurality of ceramic porous tubes constituting the gas rectifier are provided at least vertically in a two-stage staggered arrangement. When multiple ceramic porous tubes of a gas rectifier are arranged in multiple stages, the air piping to be supplied to each stage is divided for each stage, and an open / close valve is provided in each stage's piping to enable switching. The combustion furnace integrated gas cooling tower according to any one of claims 1 to 3.

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