JP2004003823A - Method for preventing gas leak from waste casting device of gasification melting furnace, and waste input device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preventing gas leak from waste casting device of gasification melting furnace, which perfectly prevents the gas leak from a waste casting device even in operation at a positive pressure, and also to provide the waste input device. <P>SOLUTION: When a waste is supplied to the body of the gasification melting furnace through the casting device having a hopper and a pusher, the steam evaporated from the waste is cooled and condensed between the outlet of the casting device and the body of the gasification melting furnace, and the pores within the waste layer are filled with the condensate. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for preventing gas leakage from a waste charging device of a gasification and melting furnace and a waste charging device. TECHNICAL FIELD The present invention relates to a technology for preventing gas leakage from a waste input device provided to supply the same and the like, and a novel waste input device provided with preventive measures.
[0002]
[Prior art]
In recent years, a gasification and melting furnace that can simultaneously reduce the volume and detoxification of refuse and waste has attracted attention (see, for example, FIG. 4). Most of such gasification and melting furnaces 1 have been operated with a furnace internal pressure of negative pressure. 3 (a) and 3 (b) so that excessive air does not enter the furnace from the hopper 7 into the charging device 3 for charging the waste 2 or the like to be treated into the gasification and melting furnace 1. ), Mechanical partitioning means such as a combination of a pusher 4 and a damper 5 and a rotary valve 6 are provided, and gas sealing is performed by these partitioning means and the layer thickness of the waste 2 itself.
[0003]
By the way, when operating at negative pressure, the above-mentioned seal also played a sufficient role, but the gasification and melting furnace generates flammable gas, and if air enters, there is a danger of explosion. Gasification and melting furnaces operating under pressure are increasing. For operation at this positive pressure, there is some gap in the sealing by the above-mentioned partitioning means such as the damper 5 and the rotary valve 6 and the thickness of the waste 2 itself. There was a case where it leaked to the hopper opening of the waste input device (however, the inside of the hopper is ventilated, so the external environment does not deteriorate).
[0004]
[Problems to be solved by the invention]
In view of such circumstances, the present invention provides a method of preventing gas leakage from a waste charging device of a gasification and melting furnace and a method of charging waste, which can completely prevent gas leakage from a waste charging device even when operating at a positive pressure. It is intended to provide a device.
[0005]
[Means for Solving the Problems]
The inventor conducted intensive research to achieve the above object, and realized the results in the present invention.
[0006]
That is, in the present invention, when supplying waste to the main body of the gasification and melting furnace through the charging device equipped with a hopper and a pusher, the waste evaporates from the waste between the main bodies of the gasification and melting furnace from the outlet of the charging device. A method for preventing gas leakage from a waste charging device of a gasification and melting furnace, wherein steam is cooled and condensed, and the condensate is used to fill gaps in a waste layer. Here, in addition to the steam, the gasification component of the waste may be cooled and solidified. Further, in the present invention, a gas leak is detected at the opening of the hopper, and an amount of water adjusted according to the amount of the gas leak is sprayed on the waste to increase the moisture in the waste, and a charging device of the charging device is provided. It is preferable to cool and condense the water vapor evaporated from the waste between the main body of the gasification melting furnace from the outlet, and to fill the gap between the waste with the condensate. In this case, it is preferable that the amount of gas leakage is determined based on the concentration of CO in the atmosphere around the opening of the hopper, and water or steam can be used as the moisture, and sludge or slurry may be contained.
[0007]
Further, in the present invention, the outer peripheral wall of the waste passage between the outlet of the charging device and the main body of the gasification and melting furnace may be indirectly heated so as to promote evaporation of moisture in the waste. In the indirect heating, a flow path for a hot fluid such as hot air or water vapor may be provided on the outer peripheral wall, or electric heating may be performed using an electric heater or a microwave application device.
[0008]
The present invention also provides a hopper having an open top and receiving waste, a pusher provided at the bottom of the hopper for pushing waste, and a waste passage for guiding the waste to a main body of the gasification and melting furnace. A waste introduction device for a gasification and melting furnace, comprising: a cooling device for the waste passage. Further, in the present invention, a gas concentration meter for measuring a gas component in the vicinity of an opening of the hopper, a spray nozzle provided on an entrance side of the waste passage and spraying water on the waste, and a cooling means for the waste passage And a water flow controller that determines the amount of water spray based on the value measured by the gas concentration meter and adjusts the opening of an on-off valve connected to the spray nozzle. In this case, on the entrance side of the waste passage, a damper that can shut off the passage is provided, or a pusher provided at the bottom of the hopper for pushing out waste and a passage provided on the entrance side of the waste passage. A rotary valve may be provided in place of the damper that allows the valve to be shut off. Preferably, the cooling means for the waste passage is a water-cooled jacket. Further, in the present invention, it is preferable that a heat source for indirectly heating the outer peripheral wall is provided on the outer peripheral wall of the waste passage between the cooling means and the gasification and melting furnace.
[0009]
In the present invention, in the waste charging device of the gasification and melting furnace, the radiant heat from the furnace or other heating sources evaporates the moisture in the waste, and the waste is generated in a passage leading to the furnace. Since the steam is cooled and condensed, and the condensate is used to fill the gap between the wastes, sufficient sealing performance can be ensured. When the water content of the waste itself is small, the above effect can be obtained by spraying the water with the water and increasing the water content of the waste. Further, in the present invention, since the spray amount of water is adjusted according to the gas leak amount measured by the gas concentration meter, the waste injection device can be used without using a conventional damper or rotary valve. Gas leakage can be almost completely prevented. At this time, if a heat source is provided on the outer peripheral wall of the waste passage between the cooling means for the waste passage and the gasification and melting furnace, the moisture in the waste can be sufficiently evaporated in the waste passage, and the cooling means Can condense a large amount of water vapor. Thereby, even when the water content in the waste is relatively small, the effect of preventing gas leakage from the waste input device is large.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described, taking into account the circumstances that led to the invention.
[0011]
First, the inventor of the present invention opened a top as shown in FIG. 1 to receive the waste 2, a pusher 4 provided at the bottom of the hopper 7 to push out the waste 2, Using a waste introduction device 3 having a waste passage 9 leading to the main body of the gasification and melting furnace 1, the compressed waste 2 is supplied to the gasification and melting furnace 1, and the inside of the furnace is set to a positive pressure of 20 to 30 kPa. The operation was carried out, and the actual state of gas leakage from the waste input device 3 was investigated. As a result, the gas in the furnace may pass through the waste input device 3 and leak out of the furnace from the hopper 7. In such a case, in the past, while venting the leaked gas to the outside with a ventilator, measures have been taken to reduce the amount of waste 2 to reduce the pressure inside the furnace. In addition to the danger, problems such as a reduction in the amount of processing have occurred.
[0012]
Then, the inventor has identified that the cause of the gas leakage is a gap between the wastes, and has focused on the fact that water contained in the waste can be used to prevent the gas leakage. In other words, the water contained in the waste is evaporated between the main body of the gasification and melting furnace from the outlet of the charging device, the water vapor is cooled and condensed, and the condensate fills the gap of the waste causing gas leakage. It was thought that this could prevent gas leakage. Then, as shown in FIG. 2A, the moisture in the waste 2 evaporates due to radiant heat from the furnace (or another heating source may be provided) and fills the gap 14 of the waste 2. However, gas leaks from the furnace through the gap 14. Therefore, in the present invention, as shown in FIG. 2B, the generated steam 15 is cooled and condensed in the waste passage 9 and the condensate fills the gap 14 of the waste 2. . Here, the steam 15 may include, in addition to the water vapor derived from the water content of the waste, a steam in which the waste component itself is gasified. As a specific cooling means, the waste passage 9 may be formed by a water cooling jacket 16. By doing so, gas leakage can be prevented to some extent. However, depending on the type of waste, gas leakage still often occurred even with this method.
[0013]
Therefore, it is considered necessary to measure the amount of gas leakage in order to completely resolve the gas leakage, and a small amount of gas component is continuously measured near the opening of the hopper 7 of the waste input device 3. A possible gas concentration meter 10 (in this case, the components to be measured are CO, CO ₂ , H ₂ S) was installed, and the amount of gas leakage was evaluated based on the magnitude of the measured component concentration. As a gas concentration meter, a continuous measurement is possible, and a CO concentration meter is preferable in consideration of the load on the environment. Then, the inventor analyzed the measurement results of the gas concentrations, and found that if the amount of water in the waste 2 is small, the amount of gas leakage increases, and if the amount of water increases, the amount of gas leakage decreases. Thus, it was considered that gas leakage can be prevented by spraying water on waste having a small amount of water. However, it is desirable to reduce the amount of water used as much as possible to obtain an efficient seal. As described above, it is preferable to condense water vapor or gasification components derived from the waste in the gap 14 of the waste 2. I thought. In order to materialize this idea, it is necessary to make the amount of water in the waste 2 adjustable. However, it is necessary to adjust the amount of water in the waste according to the amount of gas leakage (from several ppm of CO). Good. Therefore, a spray nozzle 11 for sprinkling water on the waste 2 is provided at the outlet of the waste input device 3, that is, on the input side of the waste passage 9. This makes it possible to linearly control the water spray amount based on the measurement value of the gas concentration meter 10. Specifically, the relationship between the concentration of a certain component in the gas and the amount of water spraying is determined in advance, and the relationship is stored in the calculator 12 (or the water amount controller), and the measured concentration is compared with the relationship. The amount of water spray may be determined, and the opening of the on-off valve 13 connected to the spray nozzle 11 may be adjusted based on the signal. In addition, the adjustment of the moisture can be performed by the operator's manual operation of the on-off valve 13 without using the above-described automatic control and utilizing the above-described relationship.
[0014]
Then, the moisture in the waste 2 adjusted in this manner cools and condenses the generated steam 15 or the gasification component of the waste in the waste passage 9 as shown in FIG. The condensate fills the gap 14 in the waste two layer. As a specific cooling means, the waste passage 9 may be formed by a water cooling jacket 16.
[0015]
When such a waste input device 3 according to the present invention is applied to the gasification and melting furnace 1, even if there is a slight gas leak when the type of waste is changed, watering can be immediately performed, and watering can be performed. By eliminating gas leakage from the furnace, the gasification and melting furnace 1 can stably treat the waste 2.
[0016]
Although FIG. 1 shows industrial water as water to be used, the same effect can be obtained by spraying steam, sludge, or a slurry containing water and other easily vaporizable liquids.
[0017]
【Example】
The waste charging apparatus according to the present invention was disposed in the gasification and melting furnace shown in FIG. 4, and the compressed industrial waste was continuously supplied to perform the gasification treatment. At that time, the supply amount of the industrial waste was 6 tons / hour, the furnace temperature was 1200 ° C., and the furnace pressure was 25 kPa. Then, the CO concentration in the atmosphere was constantly measured by a gas concentration meter provided near the opening of the hopper of the waste input device, and the measured value was input to a water amount controller to adjust the amount of water sprayed to the industrial waste.
[0018]
On the other hand, in order to confirm the effect of the present invention, before carrying out the present invention, a conventional waste charging apparatus was provided and operated under the same conditions.
[0019]
The operation results were evaluated based on the CO concentration, which is representative of the amount of gas leakage, and the change over time in the CO concentration is shown in FIGS. Here, FIG. 5A shows an example in which cooling means is not provided in the waste passage (conventional method), and FIG. 5B shows an example in which cooling means is provided in the waste passage (method of the present invention). 5) and FIG. 5 (c) show an example in which a cooling means is provided in the waste passage and a CO concentration meter is provided to detect the CO concentration, and when the measured value exceeds 50 ppm, water spraying is performed ( The present invention).
[0020]
5 (a) to 5 (c), it is clear that gas leakage in the hopper is almost eliminated according to the present invention.
[0021]
Further, in the gasification and melting furnace shown in FIG. 4, as shown in FIG. 6, flow paths 21 for hot air 20 are installed above and below the waste passage, and water contained in the waste 2 in the waste passage 9 is provided. The water was cooled by the water cooling means 16.
[0022]
Using the gasification and melting furnace 1 provided with a waste passage as shown in FIG. 6, while varying the temperature of the hot air 20 supplied to the hot air flow passage 21, the amount of water in the waste 2 and the introduction of the waste are changed. The relationship with the CO concentration measured at the entrance of the device was determined. FIG. 7 shows the result.
[0023]
As is clear from FIG. 7, when the moisture in the waste is sufficiently high, there is no gas leakage at the entrance of the waste input device even if hot air is not supplied into the flow passage 21 of the hot air 20. However, when the amount of water decreases, gas leakage is observed. In this case, if the hot air 20 is supplied to the hot air flow passage 21 installed in the waste passage, the degree of gas leakage at the entrance of the waste input device is reduced even if the moisture in the waste is low. Therefore, according to the present invention, when the temperature of the hot air sent to the hot air flow passage 21 is set to 400 ° C. or more in the water range of about 40 to 60% contained in ordinary general waste, the waste charging apparatus inlet Gas can be reduced to a level that does not cause a practical problem.
[0024]
【The invention's effect】
As described above, according to the present invention, it is possible to achieve gas sealing of a waste input device using waste itself without relying on a mechanical seal such as a damper or a rotary valve. As a result, gas leakage from the gasification and melting furnace of wastes operated at positive pressure was eliminated.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a charging device for a gasification and melting furnace according to the present invention.
FIG. 2 is an enlarged view of a part circled in FIG. 1 for explaining a behavior of gas in a furnace in a waste layer, wherein (a) shows a case where moisture in the waste is insufficient. Shows a case in which the gap between the waste layers is made of condensed water.
3A and 3B are cross-sectional views showing a conventional waste charging apparatus for a gasification and melting furnace, wherein FIG. 3A is a system in which a hopper is provided with a pusher and a damper, and FIG. 3B is a system in which a hopper is provided with a rotary valve. It is a method.
FIG. 4 is a cross-sectional view showing an example of a gasification melting furnace.
FIG. 5 is a diagram showing a change with time of the CO concentration measured near the opening of the hopper of the waste input device. FIG. 5 (a) shows a case where no cooling means is provided in the waste passage (conventional method); ) Is a case where a cooling means is provided in the waste passage (the method of the present invention), and (c) is a case where a cooling means is provided in the waste passage and a CO concentration meter is provided to detect the CO concentration (the method of the present invention). ).
6 is a cross-sectional view showing another embodiment of the charging apparatus for the gasification and melting furnace according to the present invention shown in FIG.
7 is a diagram showing the relationship between the amount of water in waste in the gasification and melting furnace shown in FIG. 6 and the CO concentration measured at the entrance of the waste input device.
[Explanation of symbols]
1 Gasification and melting furnace 2 Waste (garbage)
Reference Signs List 3 waste input device 4 pusher 5 damper 6 rotary valve 7 hopper 8 waste cutting machine 9 waste passage 10 gas concentration meter 11 spray nozzle 12 arithmetic unit (water flow controller)
13 On-off valve 14 Gap 15 Steam (gas)
16 Water cooling jacket 17 Cooling water 18 Melt 19 Furnace gas flow 20 Hot air 21 Hot air flow path 22 Hot air thermometer

Claims (8)

When supplying waste to the main body of the gasification and melting furnace through an input device equipped with a hopper and a pusher,
Cooling the water vapor evaporated from the waste between the main body of the gasification and melting furnace from the outlet of the charging device to condense the water, and filling the gap between the wastes with the condensate; A method for preventing gas leakage from equipment. When supplying waste to the main body of the gasification and melting furnace through an input device equipped with a hopper and a pusher,
A gas leak is detected at the opening of the hopper, and an amount of water adjusted according to the amount of the gas leak is sprayed on the waste to increase the moisture in the waste. A method for preventing gas leakage from a waste charging device of a gasification and melting furnace, wherein water vapor evaporated from waste is cooled and condensed between the main bodies, and the condensate is filled in a gap between the wastes. 3. The method according to claim 2, wherein the amount of gas leakage is determined based on an atmospheric CO concentration around an opening of the hopper. The indirect heating of the outer peripheral wall of the waste passage between the charging device outlet and the main body of the gasification and melting furnace is performed so that evaporation of moisture in the waste is promoted. The method for preventing gas leakage from a waste introduction device of a gasification and melting furnace as described in the above. A gasification / melting furnace comprising a hopper having an open top for receiving waste, a pusher provided at the bottom of the hopper for pushing out waste, and a waste passage for guiding the waste to a main body of the gasification / melting furnace; Waste input device,
A waste introduction device for a gasification and melting furnace, comprising a cooling means in the waste passage. A gasification / melting furnace comprising a hopper having an open top for receiving waste, a pusher provided at the bottom of the hopper for pushing out waste, and a waste passage for guiding the waste to a main body of the gasification / melting furnace; Waste input device,
A gas concentration meter for measuring a gas component in the vicinity of the opening of the hopper, a spray nozzle provided on the entrance side of the waste passage, for spraying water on the waste, and cooling means for the waste passage, and A waste gas injection device for a gasification and melting furnace, comprising: a water flow controller that determines a water spray amount based on a value measured by a gas concentration meter and adjusts an opening degree of an on-off valve connected to a spray nozzle. The waste charging device of a gasification and melting furnace according to claim 4 or 5, wherein the cooling means of the waste passage is a water-cooled jacket. The gasification and melting according to any one of claims 5 to 7, wherein a heat source for indirectly heating the outer peripheral wall is provided on an outer peripheral wall of a waste passage between the cooling unit and the gasification and melting furnace. Furnace waste input device.

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