JP3454576B2 - Waste treatment apparatus and method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention thermally decomposes waste (general waste such as municipal solid waste discharged from homes and offices, industrial waste such as waste plastic, and other combustible materials), and The present invention relates to a waste treatment technology for burning and treating thermal decomposition products.

[0002]

2. Description of the Related Art This type of waste treatment technology is disclosed in West German Patent Publication No. 3725704.8, West German Patent Publication N
o. 3811820.3 and Japanese Patent Application Laid-Open No. 1-49816. In the technologies disclosed in these publications, waste containing a combustible material is heated to be thermally decomposed, and a thermal decomposition product (a low temperature carbonization gas and a thermal decomposition residue mainly composed of a non-volatile component) generated thereby is decomposed. The separated char) is burned, the exhaust gas of this combustion is guided to a waste heat boiler to generate steam, and the steam is used to generate power to recover heat energy.

Further, when the pyrolysis products are burned, the combustion residue such as ash is melted into slag at a high temperature (generally, 12
It is also possible to convert the combustion residue into slag that can be reused as a building, road aggregate, etc. by burning at a temperature of about 00 ° C or higher). In this case, an inorganic harmful substance such as a heavy metal oxide generated by thermal decomposition can be enclosed and processed in the form of an ash-melted solidified product without the risk of flowing out to the environment.

[0004] In addition, according to such a technique, valuable substances such as iron and non-ferrous substances after separating char from the pyrolysis residue can be recovered in a non-oxidized state as slightly large coarse particles, and dibenzoxine chloride and dibenzofuran chloride can be recovered. It also has many advantages such that organic harmful substances such as are not emitted, and waste heat of flue gas can be effectively used.

However, when the waste is introduced into the thermal decomposition reactor at room temperature or the like, in the thermal decomposition reactor, in addition to the amount of heat required for thermal decomposition, the temperature of the waste is raised to the temperature of the thermal decomposition reactor. Needs a heat quantity of. Generally, the amount of heat required for this temperature increase is much larger than the amount of heat required for the thermal decomposition itself. Especially when the waste contains water,
Not only sensible heat but also latent heat of evaporation of water must be supplied,
The amount of heat required in the pyrolysis reactor is very large. For example, municipal solid waste contains at least 30% by weight, and in the case of a large amount, about 60% by weight, and the latent heat of vaporization of this water is one half or more of the total amount of heat required in the thermal decomposition reactor. Reach

Since such a large amount of heat is required,
If such heat quantity can be self-sufficient in the system of the waste treatment facility, it is advantageous from the viewpoint of reducing the waste treatment cost. As a technique for self-sufficing the amount of heat required in such a thermal decomposition reactor, European Patent Publication No. There is a technology disclosed in 0360052A1.

That is, according to the technique disclosed in the above publication, an inner lining is provided on the waste input side in the thermal decomposition reactor, and a heat medium (thermal oil, hot water, saturated steam or steam mixed water) is circulated. The heat source for this heat medium is self-sufficient from the steam turbine or waste heat system in the system of the waste treatment facility. Further, a burner is provided on the discharge side of the low-temperature carbonization gas and the thermal decomposition residue in the pyrolysis reactor, and the fuel of this burner is self-sufficient by partial combustion of the low-temperature carbonization gas generated in the pyrolysis reactor. Therefore, the waste is self-sufficiently heated by indirect heating in the first half and direct heating in the latter half of one pyrolysis reactor.

[0008] With the above-mentioned structure, the waste that is put into the pyrolysis reactor moves from the waste input side to the low temperature carbonization gas and the discharge side of the pyrolysis residue. In this process, first, on the waste input side, 10
It is heated to 0 ° C and the water is evaporated to dryness. The steam generated by this drying is sucked out of the thermal decomposition reactor by a pump or the like. The waste after drying is thermally decomposed by being heated by the heat of the flame of the burner on the discharge side of the low temperature carbonization gas and the thermal decomposition residue.

[0009]

However, in the technique of self-sufficient heat quantity required in the above-mentioned thermal decomposition reactor, since both the above-mentioned drying and thermal decomposition are carried out in the same thermal decomposition reactor, thermal decomposition is carried out. It is not possible to sufficiently prevent the steam generated on the waste input side in the reactor from mixing with the low temperature carbonization gas generated on the discharge side of the thermal decomposition residue. Also,
It is not possible to sufficiently prevent low-temperature carbonization gas from being mixed into the steam to be sucked out.

When the low-temperature carbonization gas contains a large amount of water vapor, the low-temperature carbonization gas and the char separated from the thermal decomposition residue are burnt at high temperature after pyrolysis, and the calorific value is lowered, resulting in insufficient temperature. Therefore, molten slag such as ash may not be formed. Therefore, as described above, if all the steam sucked out of the pyrolysis reactor by the pump or the like is sent to the high temperature combustion chamber for processing, the calorific value of the gas and the char is greatly lowered, and combustion cannot be performed at high temperature. Needless to say. On the other hand, in the steam sucked out of the pyrolysis reactor, in addition to the malodorous substances emitted from the waste,
As long as it contains flammable low-temperature carbonization gas, it cannot be released into the atmosphere as it is. If a combustion facility is provided separately from the high temperature combustion chamber and such a facility is used to treat such steam, the construction cost of the waste treatment facility will be high.

The present invention is a waste treatment technique in which waste is pyrolyzed and the pyrolysis product is burned to a temperature at which the combustion residue becomes molten slag to be treated, and water in the waste is sufficiently removed. It is an object of the present invention to provide a waste treatment apparatus and method that can later perform thermal decomposition of waste and thus prevent a situation in which molten slag such as ash cannot be formed due to insufficient temperature.

[0012]

In order to solve the above-mentioned problems, the waste treatment of the present invention is conducted at a temperature of about 200 ° C. or below.
It is dried by heating it to a temperature where it can be dehydrated.
The waste is introduced into the pyrolysis reactor and heated to pyrolyze it.
Pyrolysis residue consisting of low-temperature carbonization gas and mainly non-volatile components
The char separated from the distillate and separated from this pyrolysis residue.
And the temperature at which the combustion residue of the low temperature carbonization gas can be turned into molten slag
And recovers the heat of combustion exhaust gas generated by this combustion.
The heat of the combustion exhaust gas that has undergone this heat recovery process
In addition to using as a heat source for drying, it also contains the steam generated by this drying.
The exhaust gas generated by the combustion is passed through the exhaust gas.
It is specially designed to be introduced into the buffer container to be heated and deodorized.
To collect.

Further , the combustion atmosphere in the combustor can be dried.
By introducing a portion of the gas containing the resulting steam
Therefore, it is desirable to suppress excessive high temperature in combustion.

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

According to the present invention , the waste gas generated by the combustion of the low-temperature carbonization gas and the char and flowing through the flue is used as a heat source to heat the waste to a temperature of about 200 ° C. or lower at which it can be dehydrated, It can be dried by a self-contained heat source. The temperature is set to about 200 ° C. or lower because the thermal decomposition of waste starts at about 200 ° C., so that inflammable low-temperature carbonization gas is not mixed in the steam generated by drying. This is because the waste should be kept at about 200 ° C. The temperature at which the temperature is about 200 ° C. or less and at which dehydration is possible is specifically about 100 to 200 ° C., more preferably about 100 to 150 ° C. 150 ° C
In the following, adhesion of the waste plastic or the like to the heat transfer surface due to melting is less likely to occur.

The drying method is also an indirect heating scheme indirectly heat exchanged with the waste and combustion exhaust gas, may be a direct heating scheme to introduce directly the flue gas waste. The direct heating method has an advantage over the indirect heating method in that the efficiency of heat exchange between the combustion exhaust gas and the waste is high and the dryer equipment can be made compact. Since the indirect heating method does not mix the odorous substances emitted from the waste because the steam generated from the waste does not mix with the combustion exhaust gas, it is easier to treat the combustion exhaust gas after use for drying the waste compared to the direct heating method. There are advantages. In addition, but it may also be used in combination with direct heating method and an indirect heating system. Combustion exhaust gas is simultaneously sent to waste that is heated by indirect heat exchange with combustion exhaust gas.This combined method is more efficient than the indirect heating method alone and the direct heating method alone. The product can be dried.

In each invention, the steam generated by the indirect heating method, or the combustion exhaust gas containing the steam after being used by the direct heating method, the direct heating method, and the combined indirect heating method is discharged to the outside of the dryer. The fully dehydrated waste separated from the waste can be transported to the pyrolysis process. As described above, according to the present invention, the drying process and the thermal decomposition process of waste are completely separated, and the heating and drying temperature is kept at a temperature at which thermal decomposition does not occur in the drying process. The steam generated in the process does not mix with the low-temperature carbonization gas generated in the pyrolysis process, and there is no risk that molten slag, such as ash, will not be lost due to insufficient temperature when the low-temperature carbonization gas and char are burned at high temperature. . Also,
Since the steam generated in the drying process does not contain combustible gas,
There is no need to install special combustion equipment to treat this steam, and there is no needless increase in the construction cost of the waste treatment equipment.

Steam generated from waste by indirect heating,
Alternatively, the combustion exhaust gas containing steam used in the direct heating method, the direct heating method, and the indirect heating combined method contains the odor component contained in the waste, so remove the odor before releasing it to the atmosphere. Is desirable for environmental protection . Starting
In the case of Ming, a buffer provided in the flue at the exit of the combustor is equipped with steam containing such odorous components and gas containing combustion exhaust gas.
It is deodorized by being led to a container for use. That is, the buffer container
The high temperature flue gas immediately after combustion of the low temperature carbonization gas and char at the temperature at which the combustion residue becomes molten slag is circulated, so the introduced steam and odor components in the flue gas are high temperature flue gas. Ru is deodorized is burned by.
The buffer container should be designed so that the deodorizing reaction can be performed at high temperature.
It is effective to secure a sufficient residence time. It is also converted into substances that can be easily removed by the exhaust gas purification equipment installed downstream of the flue (especially ammonia, aldehydes, amines, sulfides, mercaptans, etc.). In the waste treatment technology such as the present invention, generally, a dust collecting facility for removing dust particles in the combustion exhaust gas and a gas purifying facility for desulfurization, denitration, etc. are provided on the downstream side of the inlet of the flue. It is customary to Therefore, if you are provided such facilities, the combustion exhaust gas after used for the drying of the waste direct heating method also, that Do and is discharged into the atmosphere after receiving treatment with the equipment.

When the low-temperature carbonization gas and char are burned at a temperature at which the combustion residue becomes molten slag, the combustion temperature may become excessively high. Japanese Patent Laid-Open No. 1-49816
In such a case, a technique is disclosed in which, in such a case, the temperature inside the furnace is lowered by, for example, guiding the low temperature combustion exhaust gas flowing near the outlet of the flue to the burner of the combustion melting furnace by a conduit. In this respect, as in the present invention, after the waste is dried, by introducing a part of the combustion exhaust gas containing steam or steam separated from the waste into the combustion atmosphere of the low-temperature carbonization gas and char, the combustion temperature can be increased. By lowering the temperature and suppressing the excessive high temperature, it is not necessary to specially provide a conduit or the like for guiding the low temperature combustion exhaust gas as in the conventional case. In this case, it goes without saying that the specific temperature of the excessive high temperature, the amount of steam to be introduced and the amount of combustion exhaust gas containing steam, the temperature, the amount of water, etc. should be adjusted in consideration of various conditions. Nor. In addition, the odor component in the combustion exhaust gas containing water vapor and steam introduced into the combustion atmosphere of the low temperature carbonization gas and char in this way is
It is burnt with low-temperature carbonization gas and char to be deodorized or converted into a substance that can be easily removed by exhaust gas purification equipment downstream of the flue.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall system diagram of a waste treatment device according to a first embodiment of the present invention. Reference numeral 1 denotes a dryer as an example of the dryer in the present invention, which can be configured using, for example, a general rotary kiln-like thermal decomposition drum. Reference numeral 2 denotes a hopper that puts waste into the dryer 1. The waste is subjected to predetermined heating and drying (this will be described later), and is conveyed by the conveying device 3 such as a feeder as an example of the conveying means in the present invention, and the thermal decomposition reactor as an example of the thermal decomposition reactor in the present invention. 4 is transported.

As the thermal decomposition reactor 4, a horizontal rotary drum (rotary kiln), a vertical shaft kiln, etc. have been conventionally used. Considering the residence time of waste in the thermal decomposition reactor 4, It is desirable to use the former.
Further, JP-A-3-63407 also shows an example of a suitable thermal decomposition reactor. The thermal decomposition reactor 4 is rotated at about 300 to 900 ° C., and 300 to 6 for extracting aluminum and the like from the thermal decomposition residue as unmelted valuables.
The waste is heated to about 00 ° C. to be pyrolyzed, and low-temperature dry distillation gas and mainly non-volatile pyrolysis residue are generated. 5
Is a carry-out device, and the pyrolysis residue is carried by a pyrolysis residue carrying line 6 provided on the bottom side of the carry-out device 5, and is guided to a pyrolysis residue separating device 7. The low-temperature carbonization gas is introduced into a combustion melting furnace 9 as an example of a combustor according to the present invention through a conduit 8 provided on the upper side of the carry-out device 5.

The residue separating device 7 is composed of, for example, a sieve, and separates the pyrolysis residue into rubble, aluminum, iron, etc. and char. The separated char is the transportation line 10
Is blown into the conduit 8 and introduced into the combustion melting furnace 9 together with the low temperature carbonization gas. Combustion air is introduced into the combustion melting furnace 9 through a ventilation pipe 11. In the combustion melting furnace 9,
This combustion air burns the low temperature carbonization gas and char.
This combustion can be a high temperature combustion by making the air ratio relatively small (the temperature is about 1200 ° C. or higher, preferably about 1300 ° C.), the ash is melted, and the cooling water tank 12 is supplied from the bottom of the combustion melting furnace 9. Drop it as a slag and take it out.

Reference numeral 13 is a flue as an example of the flue of the present invention, and guides the combustion exhaust gas generated in the combustion melting furnace 9 to the chimney 14 as an example of the discharge port of the present invention. A waste heat boiler 15 is provided in the flue 13, and high-temperature steam is obtained by heat exchange with the combustion exhaust gas guided in the flue 13. This high temperature steam is used for power generation and the like.
The flue gas after heat exchange in the waste heat boiler 15 has its dust removed by a dust collector 16 provided further downstream of the flue 13 and is introduced into a flue gas purification device 17 further provided downstream of the flue 13. It is desulfurized, denitrated, etc., and is discharged from the chimney 14 to the outside air. The dust removed by the dust collector 16 is
It is returned to the combustion melting furnace 9 via the transfer line 18, the transfer line 10 and the conduit 8.

A flue gas branch pipe that guides a part of the combustion exhaust gas flowing through the flue 13 to the dryer 1 from the flue 13 downstream of the dust collector 16 and upstream of the flue gas purification device 17, for example. 19 is branched. Reference numeral 20 is a blower provided in the flue gas branch pipe 19. The combustion exhaust gas guided by the flue gas branch pipe 19 is directly introduced into the waste in the dryer 1,
It becomes a heat source for heat drying of waste. The heating temperature of the waste is about 200 ° C. or lower, which is a temperature at which the waste can be dehydrated. Specifically, the temperature is preferably about 100 to 200 ° C, more preferably about 100 to 150 ° C.

The combustion exhaust gas containing steam used for heating and drying the waste is supplied to the inlet of the flue 13, that is, the combustion melting furnace 9 by the conduit 21 as an example of the combustion exhaust gas discharge means and gas discharge path in the present invention. To the exit of the combustion exhaust gas from. As mentioned above, a buffer container may be provided in this portion (not shown). In this way, the waste that is dried by the introduction of the combustion exhaust gas and separated from the steam generated by the drying is transported to the thermal decomposition reactor 4 by the transport device 3 such as a feeder. In order to maintain the heating temperature of the waste at the above-mentioned temperature, in consideration of various conditions such as the amount of waste in the dryer 1, its composition, and the temperature of combustion exhaust gas supplied by the flue gas branch pipe 19, the dryer is 1. Adjust the flow rate of flue gas supplied to No. 1. Further, the branch position of the flue gas branch pipe 19 from the flue 13 is not limited to the present embodiment, and may be branched from other parts. In this case, since the temperature of the combustion exhaust gas flowing differs depending on the part of the flue 13, it is necessary to consider this point in order to maintain the above-mentioned waste heating temperature.

A conduit 22 is branched from the conduit 21 as an example of the temperature adjusting means in the present invention, and a part of the combustion exhaust gas containing steam flowing through the conduit 21 can be appropriately introduced into the combustion melting furnace 9. This is because, when an excessively high temperature in the combustion melting furnace 9 is generated, the temperature inside the combustion melting furnace 9 is reduced by introducing the combustion exhaust gas that is cooled by flowing through the dryer 1 and further contains steam. The temperature is returned to the proper temperature. Therefore, when introducing such combustion exhaust gas, it is necessary to adjust the introduction amount in consideration of various conditions such as a specific temperature of excessive high temperature, the introduction amount of combustion exhaust gas containing steam to be introduced, temperature, and water content. Needless to say.

Next, the operation of this embodiment will be described. According to the present embodiment, the waste gas generated by the combustion of the low-temperature carbonization gas and the char and flowing through the flue 13 is used as a heat source to heat the waste to a temperature of about 200 ° C. or less and at which the waste can be dehydrated, and self-sufficient It can be dried by a heat source. The temperature is set to about 200 ° C. or less because the thermal decomposition of the waste starts at about 200 ° C., so that the steam generated by drying and the combustible low-temperature carbonization gas do not mix, This is because the waste temperature should be kept at about 200 ° C.

The steam generated in the drier 1 is discharged to the outside of the drier 1 through the conduit 21 and separated from the waste, and only the sufficiently dehydrated waste can be conveyed to the pyrolysis reactor 4. . Thus, in this embodiment, the waste drying process and the thermal decomposition process were completely separated, and in addition, the heating and drying temperature was kept at a temperature at which thermal decomposition did not occur in the drying process.
Unlike the prior art, steam generated in the drying process and low-temperature carbonization gas generated in the thermal decomposition process do not mix,
When the low-temperature carbonization gas and the char are burned at high temperature in the combustion melting furnace 9, there is no risk that molten slag such as ash cannot be formed due to insufficient temperature. Further, since the steam generated in the drying process does not contain combustible gas, it is not necessary to install a special combustion facility for treating the steam, and the construction cost of the waste treatment facility is not unnecessarily increased.

The combustion exhaust gas containing water vapor introduced through the conduit 21 is introduced to the inlet of the flue 13, that is, the outlet of the combustion exhaust gas from the combustion melting furnace 9. At the inlet of the flue 13, the high temperature combustion exhaust gas immediately after the low temperature carbonization gas and the char are burned in the combustion melting furnace 9 at a temperature at which the combustion residue becomes molten slag is circulated. Therefore, the odorous component in the flue gas containing the introduced steam is burned by this high temperature flue gas to be deodorized or changed into a substance that can be easily removed by the gas purifier 17 downstream of the flue. In the waste treatment technique as in the present embodiment, a dust collector 16 for removing dust in the combustion exhaust gas and a flue gas purification device 17 for desulfurization and denitration are provided downstream of the inlet of the flue 13. Therefore, the combustion exhaust gas used for drying the waste is also discharged into the atmosphere after being processed by the dust collector 16 and the flue gas purification device 17.

According to the present embodiment, after the waste is dried, a part of the combustion exhaust gas containing the steam separated from the waste is introduced into the combustion atmosphere of the low temperature carbonization gas and char to lower the combustion temperature. The excessive high temperature can be suppressed. Therefore, it is not necessary to specially provide a conduit or the like for guiding low-temperature combustion exhaust gas as in the conventional case. In this case, it goes without saying that the specific temperature of the excessive high temperature, the amount of steam to be introduced and the amount of combustion exhaust gas containing steam, the temperature, the amount of water, etc. should be adjusted in consideration of various conditions. Nor. In addition, the odorous components in the flue gas containing steam and steam introduced into the combustion atmosphere of the low-temperature carbonization gas and char in this manner are burned together with the low-temperature carbonization gas and char to be deodorized or flue gas purifier 17. Converted to a substance that can be easily removed.

Further, the heating and drying method using the combustion exhaust gas of this embodiment uses a direct heating method in which the combustion exhaust gas is directly introduced into the waste. When the direct heating method is used, the efficiency of heat exchange between the combustion exhaust gas introduced into the dryer 1 and the waste is higher than that of the indirect heating method of the second embodiment described later, and the equipment of the dryer 1 is used. Has the advantage of being compact.

For reference, the results of bench test grade experiments conducted by the present inventors using the waste treatment apparatus having the above-described structure are shown below. The waste treatment capacity of the used waste treatment equipment is 8 kg / hr. Table 1 is a table showing the material balance and heat balance of the dryer 1, and Table 2 is a table showing the material balance and heat balance of the thermal decomposition reactor 4. Also, Table 3
6 is a table showing a material balance and a heat balance of the thermal decomposition reactor 4 when the dryer 1 is removed by the same device as the comparative example and the waste is not dried. In any table
The term “crushed waste” indicates the wastes that were the subject of this experiment, and the composition is shown in each table. In Table 1, "flue gas" indicates combustion exhaust gas introduced as a heating and drying heat source. In Tables 2 and 3, “heating gas” indicates the gas as the heat medium used as the heating heat source of the thermal decomposition reactor 4. In Tables 2 and 3, "decomposition gas" indicates the low temperature carbonization gas produced in the thermal decomposition reactor 4. “In” means the amount introduced into the dryer 1 or the pyrolysis reactor 4, and “out” means the dryer 1
Alternatively, the amount of discharge from the thermal decomposition reactor 4 is shown. Table 2,
As is clear from the comparison of Table 3, according to the waste treatment apparatus of the present embodiment, compared with the conventional waste treatment apparatus that does not use the dryer 1, the heating gas required as the heating source in the thermal decomposition reactor 4 is required. It has become possible to reduce the amount to less than half.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

Next, a second embodiment of the present invention will be described. FIG. 2 is an overall system diagram of a waste treatment device according to a second embodiment of the present invention. Members having the same reference numerals as those in FIG. 1 are the same members as those in the first embodiment described with reference to FIG. 1, and detailed description thereof will be omitted. The configuration of this embodiment is different from that of the first embodiment. First, the dryer 26 as an example of the dryer of the present invention is not a direct heating system like the dryer 1 of the first embodiment. The point is that the indirect heating method is adopted. That is, a jacket portion is provided on the outer wall of the dryer 1, a heat transfer tube is provided inside, and the combustion exhaust gas guided by the flue gas branch pipe 19 is circulated to the jacket portion, the heat transfer tube, etc. Heat exchange is indirectly performed between the waste in 1 and the combustion exhaust gas, and the waste is heated and dried.

The steam generated by the heating and drying is discharged to the outside of the drier 26 by the steam discharging means and the conduit 23 as an example of the gas discharging path in the present invention, and the inlet of the flue 13, that is, the combustion melting furnace 9. It is introduced at the exit of combustion exhaust gas. As mentioned above, a buffer container may be provided in this portion (not shown). Further, a conduit 24 as an example of the temperature adjusting means in the present invention branches from the conduit 23, and a part of the steam introduced into the conduit 23 is appropriately introduced into the combustion melting furnace 9. The function of the conduit 24 is the same as that of the conduit 22 in the first embodiment, and by introducing steam into the combustion melting furnace 9, the temperature inside the combustion melting furnace 9 is returned to an appropriate temperature. Therefore, also in the present embodiment, when introducing such steam, the introduction temperature is adjusted in consideration of various conditions such as a specific temperature of excessive high temperature, the introduction amount of combustion exhaust gas containing steam to be introduced, temperature, and water content. Needless to say, it should. The flue gas after heat exchange is introduced into the flue 13 on the downstream side of the flue gas branch pipe 19 and on the upstream side of the flue gas purifying apparatus 17 by the conduit 25, for example.

Next, the operation of this embodiment will be described. Also in this embodiment, as in the first embodiment, there is no possibility that molten slag such as ash cannot be formed due to insufficient temperature.
Further, it is not necessary to provide a special combustion facility for treating the steam generated in the drying process, and the construction cost of the waste treatment facility is not unnecessarily increased.

The steam introduced through the conduit 23 contains odorous components contained in the waste, but since this steam is introduced into the combustion exhaust gas outlet of the combustion melting furnace 9, the high temperature combustion exhaust gas is discharged. As a result, the odorous component is burned to be deodorized or converted into a substance that can be easily removed by the flue gas purifying device 17.

By introducing a part of the water vapor separated from the waste into the combustion atmosphere of the low temperature carbonization gas and char through the conduit 24, the combustion temperature can be lowered and the excessive high temperature can be suppressed. Therefore, it is not necessary to specially provide a conduit or the like for guiding low-temperature combustion exhaust gas as in the conventional case. In this way, the odorous components in the steam introduced into the combustion atmosphere of the low-temperature carbonization gas and the char are burnt together with the low-temperature carbonization gas and the char to be deodorized or changed into a substance that can be easily removed by the flue gas purification device 17. .

The flue gas that has undergone heat exchange in the dryer 26 is supplied to the flue 13 upstream of the flue gas purifying device 17 through the conduit 25.
Since it is introduced into the
After denitration, etc., it will be discharged into the atmosphere. In this way, if the heating and drying method is the indirect heating method, the combustion exhaust gas as a heating source and the steam generated from the waste do not mix, so that the odorous substances emitted from the waste are not included.
Compared to the direct heating method, it is easier to treat the combustion exhaust gas after use for drying the waste.

Next, a third embodiment of the present invention will be described. FIG. 3 is an overall system diagram of a waste treatment device according to a third embodiment of the present invention. Members having the same reference numerals as those in FIG. 1 are the same members as those in the first embodiment described with reference to FIG. 1, and detailed description thereof will be omitted. The present embodiment is different from the first and second embodiments in that the heat exchanger 27 as an example of the heat exchanger of the present invention uses a direct heating method like the heat exchanger 1 of the first embodiment. And the indirect heating method like the heat exchanger 26 of the second embodiment. That is, for example, the flue gas purification device 1 is provided downstream of the dust collector 16.
7 to the flue gas branch pipe 28, 2
9, and flue gas branch pipes 28 and 29 are provided with blowers 30 and 31, respectively. Flue gas branch pipe 2
The combustion exhaust gas introduced at 8 is directly introduced into the waste in the dryer 27 and used for the direct heating method. The combustion exhaust gas guided to the flue gas branch pipe 29 is circulated to a jacket portion provided on the outer wall of the dryer 27, a heat transfer pipe provided inside, and the like by indirect heat exchange between waste and combustion exhaust gas.
Used for indirect heating method.

The combustion exhaust gas containing steam, which has been used for direct heating, is supplied to the inlet of the flue 13, that is, the combustion melting furnace 9 by the conduit 32 as an example of the steam / combustion exhaust gas discharge means and gas discharge path in the present invention. It is introduced at the combustion exhaust gas outlet. Further, a conduit 33, which is an example of the temperature adjusting means in the present invention, branches from the conduit 32, and a part of the combustion exhaust gas containing steam introduced into the conduit 32 is appropriately introduced into the combustion melting furnace 9. The function of the conduit 32 is the same as that of the conduit 22 in the first embodiment, and the combustion exhaust gas cooled by the dryer 27 and containing steam is burned in the combustion melting furnace 9
By introducing the above into the combustion melting furnace 9, the temperature inside the combustion melting furnace 9 which has become excessively high is returned to an appropriate temperature. Therefore, also in the present embodiment, when introducing the combustion exhaust gas containing the steam, a specific temperature of the excessive high temperature, the introduction amount of the combustion exhaust gas containing the steam to be introduced, the temperature, various conditions such as the water content is considered. It goes without saying that the introduction amount should be adjusted. The flue gas used for indirect heating is flue 1
3, for example, on the upstream side of the flue gas purifying device 17 and on the downstream side of the branch positions of the flue gas branch pipes 28, 29.

Next, the operation of this embodiment will be described. Also in this embodiment, as in the first and second embodiments,
There is no risk that molten slag such as ash cannot be formed due to insufficient temperature. Further, it is not necessary to provide a special combustion facility for treating the steam generated in the drying process, and the construction cost of the waste treatment facility is not unnecessarily increased.

The flue gas containing steam introduced through the conduit 32 contains an odor component contained in the waste, and this flue gas is discharged from the flue gas outlet of the combustion melting furnace 9 (at this portion). (A buffer container may be provided in some cases)
As a result, the odorous components are burned by the high temperature combustion exhaust gas to be deodorized or converted into a substance that can be easily removed by the flue gas purifying device 17.

A portion of the combustion exhaust gas containing water vapor separated from the waste is appropriately introduced into the combustion atmosphere of the low temperature carbonization gas and char through the conduit 33 to lower the combustion temperature,
Excessive high temperature can be suppressed. Therefore, it is not necessary to specially provide a conduit or the like for guiding low-temperature combustion exhaust gas as in the conventional case. In this way, the odorous component in the steam introduced into the combustion atmosphere of the low-temperature carbonization gas and char is
It is burnt with the low-temperature carbonization gas and char to be deodorized or converted into a substance that can be easily removed by the flue gas purifying device 17.

The flue gas after heat exchange in the dryer 27 is introduced into the flue 13 upstream of the flue gas purifying device 17 through the conduit 34.
Since it is introduced into the
After denitration, etc., it will be discharged into the atmosphere.

When the direct heating method and the indirect heating method are used together as in this embodiment, the combustion exhaust gas is blown directly to the waste heated by the indirect heating method in the dryer 27. Become. According to such a direct heating / indirect heating combination method, rather than the direct heating method alone and the indirect heating method alone as in the first and second embodiments,
The waste can be efficiently dried.

[0056]

According to the present invention described above, the waste treatment technology for thermally decomposing waste and burning the pyrolysis product to a temperature at which the combustion residue becomes molten slag for treatment is described as follows.
Waste that enables thermal decomposition of the waste after sufficient removal of water in the waste, thus preventing the situation where molten slag such as ash cannot be formed due to insufficient temperature in the combustion melting furnace. A processing apparatus and method can be provided.

[Brief description of drawings]

FIG. 1 is a system diagram of a waste treatment device according to a first embodiment of the present invention.

FIG. 2 is a system diagram of a waste treatment device which is a second embodiment of the present invention.

FIG. 3 is a system diagram of a waste treatment device according to a third embodiment of the present invention.

[Explanation of symbols]

1, 26, 27 dryer 3 Conveyor 4 Pyrolysis reactor 9 Combustion melting furnace 13 flue 21, 23, 32 conduits 22, 24, 33 conduits

─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A 64-49816 (JP, A) JP-A 4-349988 (JP, A) JP-A 54-127162 (JP, A) JP-A 55- 43368 (JP, A) JP-A-63-99412 (JP, A) JP-A-5-322149 (JP, A) JP-A-3-63407 (JP, A) Actual Kaihei 5-17322 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F23G 5/027 F23G 5/04 F23G 5/50

Claims (4)

(57) [Claims] 1. Waste is dehydrated at a temperature of about 200 ° C. or lower.
A dryer for heating to dry temperature and drying, a pyrolysis reactor for heating and pyrolyzing the dried waste to separate it into a low temperature carbonization gas and a pyrolysis residue mainly consisting of non-volatile components, and A combustor that combusts the char separated from the pyrolysis residue and the low-temperature carbonization gas at a temperature at which the combustion residue can be melted into slag, and a combustion exhaust gas provided at the outlet of the combustor.
From the buffer container into which is introduced
A heat recovery means for recovering the heat of the exhaust gas discharged,
The combustion exhaust gas downstream of the heat recovery means is used as a heat source for the dryer.
And means for supplying water vapor generated in the dryer.
Means for introducing a gas containing the gas into the buffer container . 2. The steam discharged from the dryer
Waste processing apparatus according to claim 1, characterized in that it comprises a temperature regulating means for suppressing the excessive hot combustor by introducing a portion of the gas before Symbol combustor comprising. 3. The waste is dehydrated at a temperature of about 200 ° C. or lower.
Heating to high temperature and drying, and the dried waste is introduced into a pyrolysis reactor and heated to pyrolyze, and pyrolysis consisting of low-temperature carbonization gas and mainly non-volatile components. A step of separating into a residue, a step of combusting the char separated from the pyrolysis residue and the low-temperature carbonization gas at a temperature at which a combustion residue can be molten and slag, and a combustion generated by this combustion
And a step of recovering heat of exhaust gas, the drying step,
The waste due to the heat of the combustion exhaust gas that has undergone the heat recovery step
The gas containing the steam generated by this drying.
The exhaust gas generated by combustion in the combustion process
A waste treatment method in which the waste is introduced into a container for baffles and deodorized by heating . 4. The drying process is performed in a combustion atmosphere in the burning step.
Introduce part of the gas containing the steam discharged from the process
The waste treatment method according to claim 3 , wherein excessive high temperature in combustion is suppressed.