JPH09178134A - Apparatus and method for processing waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent melting and slugging of an ash fraction and the like from failing owing to insufficient temperature upon combustion of produced low temperature carbonization gas and char by removing water in a waste and then thermally decomposing the waste. SOLUTION: A heating medium from a conduit 21b such as air is introduced into a dryer 1, which is used as a heating source to heat and dry water in the waste. The waste after dried is carried with a carrier 3 to a thermal decomposition reactor 4 for thermal decomposition. For a drying method, there may be used a direct heating one for directly introducing air of the heating medium to a waste or an indirect heating one for indirectly heat exchanging the waste and air of the heating medium, or a combined one. The heating medium containing water vapor after the use in the case of the direct heating method and the combined one and the water vapor produced in the indirect heating method are introduced into an outlet side of combustion waste gas from a combustion melting furnace 9 through a conduit 21c, and odor components are combusted and removed. A part of the water vapor and the heating medium may be properly introduced into the combustion melting furnace 9 through a conduit 22 to prevent excessively high temperature in the furnace.

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), The present invention relates to a waste treatment device and method for burning and treating pyrolysis products.

[0002]

2. Description of the Related Art The conventional waste treatment technology of this type is disclosed in the former West German Patent Publication No. 3725704.8, former West German Patent Publication No. 3811820.3 and JP-A-1-49
It is disclosed in Japanese Patent No. 816. 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 is separated from the thermal decomposition product generated by the thermal decomposition. The burned 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 encapsulated without fear of flowing out into the environment and treated in the form of an ash-melted solidified product.

[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 dibenzodioxin chloride and dibenzofuran chloride can be recovered. It also has many advantages such as not emitting organic harmful substances such as, and also effectively utilizing waste heat of flue gas.

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 the sensible heat but also the latent heat of evaporation of water must be supplied, and the amount of heat required in the thermal decomposition reactor becomes 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. 0360052A1 and European Patent Publication No. There is a technique disclosed in 0340537B1.

That is, in the technique disclosed in the former publication, an inner lining is provided on the waste input side in the thermal decomposition reactor to allow a heat medium (thermal oil, hot water, saturated steam or steam mixed water) to flow. 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 of one pyrolysis reactor and direct heating in the latter half.

[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.

Further, in the technique disclosed in the latter publication, a gas (for example, air) indirectly heated by a part of the calorific value of the low temperature carbonization gas and the combustion exhaust gas of char is guided to the thermal decomposition reactor, and the gas inside the thermal decomposition reactor is A method for indirectly heating and pyrolyzing this waste by exchanging heat with the waste is described.

[0010]

In the conventional waste treatment equipment, of the techniques for self-sufficient heat required by the pyrolysis reactor, the former is one in which both the steps of drying the waste and the subsequent pyrolysis are performed. Although intended to be performed separately, since both drying and pyrolysis are performed in the same pyrolysis reactor, the steam generated on the waste input side in the pyrolysis reactor is discharged on the pyrolysis residue discharge side. It is not possible to sufficiently prevent the low-temperature carbonization gas produced from being mixed. Further, it is not possible to sufficiently prevent the low temperature carbonization gas from being mixed into the steam to be sucked out.

When the amount of water vapor mixed in the low-temperature carbonization gas is large, the heat generation amount is lowered when the low-temperature carbonization gas and the char separated from the thermal decomposition residue are burnt at high temperature after thermal decomposition, and the temperature is insufficient. There is a risk that molten slag such as ash will 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 will be greatly reduced and combustion at high temperature will not be possible. Needless to say. On the other hand, the steam sucked out of the pyrolysis reactor contains flammable low-temperature carbonization gas in addition to the malodorous substances emitted from the waste. Can not. 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. Further, in the latter technique described above, the entire amount of water in the waste is evaporated and transferred to the low temperature carbonization gas, which lowers the amount of heat generation. Therefore, similarly to the above, the temperature inside the combustor becomes insufficient, and there is a possibility that molten slag cannot be formed.

The present invention relates to a waste treatment technology in which waste is pyrolyzed by utilizing its own waste heat of combustion, and the pyrolysis product is burned to a temperature at which a combustion residue becomes molten slag and treated. After removing some or all of the water in the waste, it is possible to carry out the thermal decomposition of the waste.
It is an object of the present invention to provide a waste treatment device and method capable of preventing a situation where molten slag such as ash cannot be formed due to insufficient temperature.

[0013]

In order to achieve the above-mentioned object, the waste treatment apparatus according to the present invention indirectly heats a waste by a heating medium to thermally decompose the waste, and a low temperature carbonization gas and a thermal decomposition residue. Pyrolysis reactor to separate into a product, a char separated from the pyrolysis residue and the low-temperature carbonization gas combustor that burns at a temperature at which combustion residue can be molten slag, and combustion exhaust gas generated by this combustion In a waste treatment device provided with a flue that discharges to the outside air, a heat exchanger that is disposed in the flue and indirectly exchanges heat between the heating medium and the combustion exhaust gas, and the heat exchanger from the heat exchanger. Means for guiding the heating medium to the thermal decomposition reactor, and to a temperature below which the waste can be dehydrated by directly or indirectly exchanging heat between the heating medium discharged from the thermal decomposition reactor and the waste. This is a dryer that heats and dries The heating medium a structure in which and means for discharging from the dryer containing steam or water vapor generated by 燥.

Combustion in which the pyrolysis reactor for separating the low-temperature carbonization gas and the pyrolysis residue, the char separated from the pyrolysis residue and the low-temperature carbonization gas are burned at a temperature at which the combustion residue can be melted into slag. In a waste treatment apparatus comprising a reactor and a flue that discharges the combustion exhaust gas generated by this combustion to the outside air, the heating medium and the waste that have exited the thermal decomposition reactor are indirectly heat-exchanged. And this waste
A dryer that heats and dries to a temperature at which it can be dehydrated at approximately 200 ° C. or less, a steam discharge means that discharges the steam generated by this drying to the outside of the dryer, and a waste after the drying is the thermal decomposition reactor. And a carrying means for carrying out the thermal decomposition.

The heating medium discharged from the pyrolysis reactor is brought into direct contact with the waste, and the waste is heated to about 200 ° C.
A dryer for heating and drying to the following dehydratable temperature, a heating medium discharging means for discharging the heating medium containing water vapor separated from the waste by the drying to the outside of the dryer, and a waste after the drying. It may be configured to include a conveying unit that conveys the substance to the thermal decomposition reactor and causes the thermal decomposition.

Further, the indirect heat exchange with the heating medium leaving the thermal decomposition reactor and the direct introduction of the heating medium leaving the thermal decomposition reactor into the waste are simultaneously performed, and A dryer that heats and dries the waste to a temperature at which it can be dehydrated up to approximately 200 ° C. and steam that discharges the steam generated from the waste by this drying and the heating medium after the direct introduction to the outside of the drier. The heating medium discharging means and the conveying means for conveying the dried waste to the thermal decomposition reactor to cause the thermal decomposition may be provided.

Then, the steam discharged by the steam discharge means, the heating medium discharge means or the steam / heating medium discharge means and / or the heating medium is supplied to the flue gas outlet side of the combustion exhaust gas from the combustor, or A configuration may be provided in which a discharge passage that leads to the inside of the flue is provided.

Further, a heating medium guided in the discharge passage,
Alternatively, it is possible to adopt a configuration in which a part of steam is introduced into the combustor and a temperature adjusting means for controlling the temperature of the combustor is provided.

Further, as a waste treatment method, the waste is introduced into a thermal decomposition reactor and indirectly heated by a heating medium to be thermally decomposed, and a low temperature carbonization gas and a thermal decomposition residue mainly composed of nonvolatile components are obtained. And a step of combusting 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 an exhaust port for discharging the combustion exhaust gas generated by this combustion to the outside air. In the waste treatment method including the step of introducing the waste gas to the waste gas by a flue, the heating medium leaving the thermal decomposition reactor and the waste are indirectly heat-exchanged, and the waste is heated to approximately 200 ° C. or lower. A step of drying by heating to a temperature capable of dehydration, a step of separating water vapor generated by this drying from the waste, and a step of conveying the dried waste to the thermal decomposition reactor, Pyrolyzer A configuration that includes a pretreatment step.

Then, the heating medium is brought into direct contact with the waste, the waste is heated to a temperature at which dehydration is possible at about 200 ° C. or less and dried, and the steam generated from the waste by the drying. A step of separating the heating medium after being directly introduced into the waste from the waste, and a step of transporting the dried waste to the thermal decomposition reactor as a pretreatment step of the thermal decomposition step. It may be included.

Further, the indirect heat exchange between the waste and the heating medium leaving the thermal decomposition reactor and the direct contact of the heating medium leaving the thermal decomposition reactor with the waste are simultaneously performed. The step of drying the waste by heating it to a temperature at which it can be dehydrated at about 200 ° C. or lower; and the steam generated from the waste by this drying and the heating medium directly introduced into the waste. A step of separating from the waste, and a step of conveying the dried waste to the pyrolysis reactor,
It may be configured so as to be included as a pretreatment step of the thermal decomposition step.

Further, the separated steam and / or the heating medium is introduced into the flue on the side of the combustion exhaust gas from the combustor, or into a container provided in the middle of the flue, and the separated steam and Alternatively, it may be configured to include a step of heating and deodorizing the heating medium.

In the step of burning the char and the low-temperature carbonized gas, the char and the low-temperature carbonized gas are burned in the combustion atmosphere by introducing a part of the separated steam and heating medium. The temperature may be controlled.

According to the present invention, the heating medium is indirectly heated to a temperature suitable for thermal decomposition of waste (for example, 500 ° C. or higher) by heat exchange with a predetermined heat source, and the heating medium will be described later. The dried waste is indirectly heated and pyrolyzed. Next, after exchanging heat with this waste, the original undried waste is heated to a temperature at which it can be dehydrated below approximately 200 ° C by a heating medium cooled to an appropriate temperature (for example, about 300 ° C). It can be dried. Furthermore, if the waste heat of the combustion exhaust gas of the low temperature carbonization gas is used as the predetermined heat source, it is possible to perform drying and thermal decomposition by the self-heat source.

The drying system may be an indirect heating system in which the heating medium discharged from the thermal decomposition reactor and the waste are indirectly heat-exchanged, or a direct heating system in which the heating medium is directly introduced into the waste. Compared to the indirect heating method, the direct heating method has a higher efficiency of heat exchange between the heating medium and the waste, and the dryer equipment can be made compact. Since the indirect heating method does not mix the steam generated from the waste with the heating medium, the heating medium used for drying the waste does not contain the odorous substances emitted from the waste, so it is easier to process than the direct heating method. . Further, the direct heating method and the indirect heating method may be used together. This combined method, in which the remainder of the heating medium is simultaneously introduced into the waste that is heated by indirect heat exchange with part of the heating medium, and the generated steam is discharged, is the indirect heating method alone or the direct heating method. The waste can be dried more efficiently than if it is dried alone.

In each invention, the steam generated by the indirect heating method or the heating medium containing the steam after being used by the direct heating method or the direct heating / indirect heating combined method is discharged to the outside of the dryer. The dewatered waste separated from the waste can be transported to the pyrolysis process. in this way,
Since the drying process and the thermal decomposition process of the waste were completely separated and the heating drying temperature was kept at a temperature at which thermal decomposition did not occur in the drying process, the steam generated in the drying process and the low temperature generated in the thermal decomposition process were The dry distillation gas does not mix with each other, and when the low temperature dry distillation gas and char are burned at a high temperature, there is no fear 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 this steam, and the construction cost of the waste treatment facility is not unnecessarily increased.

Water vapor generated from waste by the indirect heating method,
Alternatively, since the heating medium containing steam used in the direct heating method, the direct heating method, and the indirect heating combined method contains the odorous component contained in the waste, the steam or the heating medium containing the odorous component should be used in the flue gas. Guided to the inlet part, the low temperature carbonization gas and char are burned by the high temperature combustion exhaust gas after burning at the temperature at which the combustion residue becomes molten slag and deodorized, or easily by the exhaust gas purification equipment installed downstream of the flue It is changed to a substance that can be removed.

After the waste is dried, a part of the steam or the heating medium containing the steam separated from the waste is introduced into the combustion atmosphere of the low temperature carbonization gas and the char in the combustor so that the combustion temperature is increased. Can be lowered, and excessive high temperature can be suppressed. At that time, the introduction amount and the like are adjusted in consideration of various conditions such as the specific temperature of the excessively high temperature, the introduction amount of the steam to be introduced and the heating medium containing the steam, the temperature and the moisture content.

[0029]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall system diagram of a waste treatment device showing a first embodiment of the present invention. The dryer 1 as an example of the dryer in the present invention can be formed using, for example, a drum such as a general rotary kiln. The waste put into the dryer 1 by the hopper 2 is
After carrying out predetermined heat drying (described later), a transport device 3 such as a feeder as an example of a transport means in the present invention, and a thermal decomposition reactor 4 as an example of the thermal decomposition reactor in the present invention.
Transported to

As the thermal decomposition reactor 4, a horizontal rotary drum (rotary kiln) or a vertical shaft kiln has been conventionally used. Considering the residence time of the waste in the thermal decomposition reactor 4, It is desirable to use the former,
Further, it is necessary to have a structure of a heat exchanger that indirectly heats waste with a heating medium. The thermal decomposition reactor 4 is a conduit 2 described later.
Using the heated air guided by 1a as a heating medium, 300
To remove aluminum or the like from the thermal decomposition residue as unmelted valuables at about 900 ° C to about 300 ° C to 600 ° C, the waste is indirectly heated and thermally decomposed, and low-temperature carbonization gas and mainly non-volatile This produces a pyrolysis residue. The thermal decomposition residue is carried by a residue carrying line 6 provided on the bottom side of the carry-out device 5, and guided to a 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 formed of, for example, a sieve or the like, and separates the pyrolysis residue into rubble, aluminum, iron, etc. and char. The separated char is blown into the conduit 8 through the transfer line 10 and introduced into the combustion melting furnace 9 together with the low temperature carbonization gas. Note that the structure may be such that it is directly introduced into the combustion melting furnace 9 from the transfer line 10.
Combustion air is introduced into the combustion melting furnace 9 through a ventilation pipe 11. In the combustion melting furnace 9, the low temperature carbonization gas and char are burned with this combustion air. 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.

Flue 1 as an example of the flue according to the present invention
Reference numeral 3 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,
High-temperature steam is obtained by heat exchange with the flue gas introduced in. This high temperature steam is used for power generation and the like. Waste heat boiler 1
The flue gas after heat exchange in 5 has its dust removed by a dust collector 16 provided further downstream of the flue 13 and is introduced into a flue gas purifier 17 further provided downstream of the flue 13 for desulfurization and After denitration, etc., the chimney 1 is passed through the induction blower 35.
4 is discharged to the outside air. The dust removed by the dust collector 16 is returned to the combustion melting furnace 9 via the transfer line 18, the transfer line 10 and the conduit 8. The transfer line 18
It is also possible to adopt a structure in which the fuel is directly returned to the combustion melting furnace 9 from.

A heat exchanger 36 is provided in the flue 13 between the combustion melting furnace 9 and the waste heat boiler 15, and the flue 13 is provided.
The air is heated to a predetermined temperature by heat exchange between the combustion exhaust gas introduced in step 1 and the air supplied from the heating medium supply pipe 19 as an example of the heating medium in the present invention.
As the heating medium, combustion gas of fuel supplied from the outside or preheated air may be used as necessary. The heated heating medium air is supplied to the conduit 21a.
To the pyrolysis reactor 4.

After the waste is indirectly heated in the pyrolysis reactor 4, the air of the heating medium whose temperature has been lowered is supplied to the conduit 2
It is discharged through 1b and further guided to the dryer 1. The blower 20 is provided in the conduit 21b. The air of the heating medium introduced through the conduit 21b is directly introduced into the waste in the dryer 1 and serves as a heat source for heating and drying the waste. The heating temperature of this waste is approximately 200 ° C. or lower, which is a temperature at which the waste can be dehydrated. Specifically, approximately 100 to 200
It is desirable to set the temperature to 100 ° C, more preferably to about 100 to 150 ° C.

The air of the heating medium containing the steam after being used for heating and drying the waste is supplied to the inlet of the flue 13 by the heating medium discharging means and the conduit 21c as an example of the heating medium discharging path in the present invention. That is, it is led to the outlet of the combustion exhaust gas from the combustion melting furnace 9. As described above, a buffer container may be provided in this portion (not shown). In this way, the waste that has been dried by the introduction of air as the heating medium and separated from the steam generated by the drying is
For example, it is conveyed to the thermal decomposition reactor 4 by a conveying device 3 such as a feeder. In addition, the thermal decomposition reactor 4 and the dryer 1
In order to maintain the heating temperature of each waste in the inside at the above-mentioned temperature, in consideration of various conditions such as the amount of waste supplied to the dryer 1 and its composition, the heating medium supply pipe 19 to the thermal decomposition reactor 4 is used. The temperature and flow rate of the air of the heating medium supplied to the dryer 1 via the above are adjusted.

A conduit 22 as an example of the temperature adjusting means in the present invention branches from the conduit 21c, and a part of the heating medium containing steam flowing through the conduit 21c 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, it is cooled by connecting the thermal decomposition reactor 4 and the dryer 1, and by introducing a heating medium containing steam, combustion is performed. It is intended to return the temperature in the melting furnace 9 to an appropriate temperature. Of course, in this embodiment, since air is used as the heating medium,
A part thereof is also used as combustion air for combustion itself in the combustion melting furnace 9. In this case, such operation is the air ratio in this combustion (ratio of the total amount of input air to the theoretical required amount of air)
Is in control. Therefore, when introducing the air of the heating medium, the introduction temperature is adjusted in consideration of various conditions such as the specific temperature of the excessive high temperature, the amount of the air of the heating medium containing the steam to be introduced, the temperature, and the water content. Needless to say, it should.

Next, the operation of this embodiment will be described. According to the present embodiment, the air of the heating medium is heated by using the combustion exhaust gas generated by the combustion of the low-temperature carbonization gas and the char and flowing through the flue 13 as a heat source, and the air after drying in the pyrolysis reactor 4 The waste is pyrolyzed by heating. afterwards,
In the dryer 1, the residual heat of the air further heats the waste to a temperature of about 200 ° C. or lower where it can be dehydrated, so that the waste can be dried by the self-contained heat source. This temperature is set to about 200 ° C or lower because the thermal decomposition of waste is about 2
Since the temperature starts from about 00 ° C., the waste temperature should be kept at about 200 ° C. or lower in order to prevent the steam generated by drying from mixing with the combustible low-temperature carbonization gas.

The steam generated in the dryer 1 is supplied to the conduit 21c.
Thus, only the waste that has been discharged out of the dryer 1 and separated from the waste and sufficiently dehydrated can be conveyed to the pyrolysis reactor 4. As described above, in the present embodiment, the drying process and the thermal decomposition process of the waste are completely separated, and the heating and drying temperature is kept at a temperature at which the thermal decomposition does 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 low-temperature carbonization gas and char are burned at high temperature in the combustion melting furnace 9, there is no fear 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 air of the heating medium containing the steam introduced through the conduit 21c is introduced into 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 odor component in the air of the introduced heating medium containing steam is burned by this high temperature combustion exhaust 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 technology as in this embodiment, the flue 13
A dust collector 16 that removes dust in the combustion exhaust gas and a flue gas purification device 17 that performs desulfurization and denitration are provided on the downstream side of the inlet of the. Therefore, the air of the heating medium 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 air of the heating medium containing the steam separated from the waste is introduced into the combustion atmosphere of the low temperature carbonization gas and the char so that the combustion temperature is increased. Can be controlled to suppress excessive high temperature, that is, the combustion temperature can be controlled. In this case, it is necessary to adjust the introduction amount in consideration of various conditions such as the specific temperature of the excessively high temperature, the introduction amount of steam to be introduced and the heating medium containing steam, the temperature, and the moisture content. Needless to say. At this time, the odor component in the air of the heating medium containing steam or steam introduced into the combustion atmosphere of the low-temperature carbonization gas and the char is combusted together with the low-temperature carbonization gas or the char to be odorless or the flue gas purification device. At 17, it is converted to a substance that can be easily removed.

The heating and drying method using the heating medium of this embodiment uses a direct heating method in which heated air is directly introduced into waste. When the direct heating method is used, the efficiency of heat exchange between the air of the heating medium introduced into the dryer 1 and waste is higher than that of the indirect heating method of the second embodiment described later, and the dryer 1 The advantage is that the equipment can be made compact.

[0042]

EXAMPLES For reference, the results of bench test-class experiments performed using the waste treatment apparatus having the above-described structure are shown below. The waste treatment capacity of the used waste treatment equipment is
It is 6.8 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. Table 3 is a table showing a material balance and a heat balance of the thermal decomposition reactor 4 when the dryer 1 is removed and the waste is not dried by the same device as a comparative example. In each of the tables, the term “crushed dust” indicates the waste that was the subject of this experiment, and the composition is shown in each table. The term "heated air" in Table 1 indicates the air of the heating medium introduced as the heating and drying heat source. In Tables 2 and 3, “heated air” indicates the air of the heating 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” indicates the amount introduced into the dryer 1 or the thermal decomposition reactor 4, and “out” indicates the amount discharged from the dryer 1 or the thermal decomposition reactor 4. The "outgoing""heatedair" of the thermal decomposition reactor 4 in Table 2 is the same as the "incoming" heated air of the dryer 1 in Table 1. As is clear from the comparison between Tables 2 and 3, the waste treatment apparatus according to the present embodiment has the following advantages over the conventional waste treatment apparatus that does not use the dryer 1.
It has become possible to reduce the required amount of heating gas as a heating source in the thermal decomposition reactor 4 to about half. Also, the maximum temperature reached in the latter stage combustion melting furnace 9 is about 8 when the dryer is provided.
It became 0 ° C. higher, and it was easier to form molten slag.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[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, in the dryer 26 as an example of the dryer of the present invention, the direct heating method as in the dryer 1 of the first embodiment is not used. The point is that the indirect heating method is adopted. That is, a heating medium introduced from the heat exchanger 37 provided in the flue 13 through the conduit 25a and the thermal decomposition reaction furnace 4 through the conduit 25b, such as air, is provided with a jacket portion on the outer wall of the dryer 1, A heat transfer tube is provided in the interior of the dryer, and the heat transfer tube is circulated in the heat transfer tube to indirectly perform heat exchange between the waste in the dryer 1 and the air of the heating medium to heat and dry the waste.

The steam generated by the heat drying is discharged to the outside of the dryer 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 described 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 similar to that of the conduit 22 in the first embodiment, and it is intended to return the temperature in the combustion melting furnace 9 to an appropriate temperature by introducing steam into the combustion melting furnace 9. Therefore, also in this embodiment, when introducing the steam,
It goes without saying that the introduction amount should be adjusted in consideration of various conditions such as the specific temperature of the excessive high temperature, the introduction amount of air of the heating medium containing steam to be introduced, the temperature and the water content. The air of the heating medium after the heat exchange is introduced into the heat exchanger 37 by the conduit 25c, is heated by the flue gas passing through the flue 13, and is circulated, for example.

Next, the operation of this embodiment will be described. Also in the present embodiment, as in the first embodiment, there is no fear 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 an odor component contained in the waste. 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 steam separated from the wastes 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. At this time, the odorous component in the steam introduced into the combustion atmosphere of the low temperature carbonization gas and the char is 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 purifying device 17. .

Since the air of the heating medium after the heat exchange in the dryer 26 is introduced and circulated in the heat exchanger 37 by the conduit 25c, it can be reused without losing its residual heat. This circulation is possible because when the heating / drying method is an indirect heating method, the air of the heating medium as a heating source and the steam generated from the waste do not mix, so that the air of the heating medium is kept clean. .

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 dryer 27 as an example of the heat exchanger of the present invention has a direct heating system like the dryer 1 of the first embodiment, The point is that an indirect heating method such as the dryer 26 of the second embodiment is used together. That is, for example, from the heat exchanger 38 provided in the flue 13 to the conduit 28
The heating medium, which is led by the conduit 28b through the a and the thermal decomposition reactor 4, for example, air here is pressurized by the blower 20 and then branched to the conduits 29a and 30. Conduit 28b
The air of the combustion medium guided by the more branched conduit 30 is directly introduced into the waste in the dryer 27 and used for the direct heating method. Similarly, a conduit 29a branched from the conduit 28b
The air of the heating medium guided to the dryer is circulated through a jacket portion provided on the outer wall of the dryer 27 or a heat transfer tube provided inside, and an indirect heating method by indirect heat exchange between waste and air of the heating medium. Used for.

The air of the heating medium used for the direct heating containing the steam is supplied to the inlet of the flue 13, that is, the combustion melting furnace by the steam / heating medium discharging means and the conduit 32 as an example of the discharging path in the present invention. 9 is introduced at the flue gas outlet. Further, from the conduit 32, a conduit 33 as an example of the temperature adjusting means in the present invention branches, and a part of the air of the heating medium containing the steam introduced to the conduit 32 is appropriately introduced.
It is introduced into the combustion melting furnace 9. The function of the conduit 33 is similar to that of the conduit 22 in the first embodiment, and by introducing air of the heating medium cooled by the dryer 27 and containing steam into the combustion melting furnace 9, the temperature becomes excessively high. It is intended to return the temperature inside the combustion melting furnace 9 to the proper temperature. Further, a part thereof is directly used as combustion air for combustion in the combustion melting furnace 9. Therefore, also in the present embodiment, when introducing the air of the heating medium containing the water vapor, various values such as a specific temperature of the excessively high temperature, the amount of the air of the heating medium containing the water vapor to be introduced, the temperature and the amount of water, etc. It goes without saying that the introduction amount should be adjusted in consideration of the conditions. The heating medium air used for indirect heating is introduced into the heat exchanger 38 by the conduit 29b, heated by the flue gas passing through the flue 13, and circulated. In addition, the heating medium supply pipe 31 that joins the conduit 29b replenishes and supplies the air of the heating medium that flows through the conduit 30 and that corresponds to the amount for the direct heating method drying.

Next, the operation of this embodiment will be described. Also in this embodiment, as in the first and second embodiments,
There is no fear that molten slag such as ash will not be lost 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 air of the heating medium containing steam introduced through the conduit 32 contains the odor component contained in the waste, and the air of this heating medium is the outlet of the combustion exhaust gas of the combustion melting furnace 9. The odor component is burned by the high temperature combustion exhaust gas so as to be deodorized or flue gas purifying device 1
At 7, the substance is changed to a substance that can be easily removed.

By appropriately introducing a part of the air of the heating medium containing water vapor separated from the waste into the combustion atmosphere of the low temperature carbonization gas and char through the conduit 33, the combustion temperature is lowered and the excessive high temperature is suppressed. can do. Further, a part thereof is directly used as combustion air for combustion in the combustion melting furnace 9. At this time, the odorous components in the steam introduced into the combustion atmosphere of the low-temperature carbonization gas and the char are burned 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 purifying device 17. It

Since the air of the heating medium after the heat exchange in the dryer 27 is kept clean, it is introduced into the heat exchanger 38 through the conduit 29b and circulated therein, so that it can be reused without losing its residual heat.

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

According to the present invention, the heating medium is indirectly heated to a temperature suitable for the thermal decomposition of waste by heat exchange with a predetermined heat source,
That is, it is heated to about 300 to 600 ° C., and the waste material after drying is indirectly heated and thermally decomposed by this heating medium. Then, after heat exchange with this waste material, the original undried waste material is heated to a temperature at which it can be dehydrated below approximately 200 ° C by a heating medium cooled to an appropriate temperature, and dried by a self-contained heat source. You can This temperature is set to about 200 ° C. or lower because the thermal decomposition of waste is about 20
Since it starts from about 0 ° C., the waste should be kept at about 200 ° C. or lower in order to prevent the flammable low-temperature carbonization gas from being mixed in the steam generated by the drying. The temperature at which the temperature is about 200 ° C. or lower and the water can be dehydrated is specifically about 100 to 200 ° C., and more preferably about 100 to 150 ° C. 150
If the temperature is below ℃, it will be difficult for the waste plastic to melt and adhere to the heat transfer surface. As the heat source for heating the heating medium to the temperature required for the thermal decomposition and drying process, any heat source supplied from the outside may be used, but as in the third embodiment, the low temperature carbonization gas and char are used. It is preferable to use the combustion exhaust gas as a heat source because it can be self-supplied in the process.

The drying system may be an indirect heating system in which the heating medium leaving the thermal decomposition reactor and waste are indirectly heat-exchanged, or a direct heating system in which the heating medium is directly introduced into the 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 steam generated from the waste with the heating medium, the heating medium used for drying the waste does not contain the odorous substances emitted from the waste, so it is easier to process than the direct heating method. There is an advantage. Further, the direct heating method and the indirect heating method may be used together. This combined method, in which the remainder of the heating medium is simultaneously introduced into the waste that is heated by indirect heat exchange with a part of the heating medium, is more effective than the indirect heating method alone or the direct heating method alone. The waste can be efficiently dried.

Such a heating medium needs to be a fluid that is chemically stable through the thermal decomposition step and the drying step. When adopting (or using together) the process of introducing it directly into the waste and drying it, the used heating medium containing steam from the waste should be used as a low-temperature carbonization gas and char to remove odor as described below. Since it will be merged with the combustion exhaust gas, it must be harmless when it is exhausted from the chimney. In practice, air or combustion gas of fuel supplied from the outside can be used.

In each of the examples, the steam generated by the indirect heating method or the heating medium 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. It is possible to transport the dehydrated waste separated from the waste 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 thermal decomposition process, and when the low-temperature carbonization gas and char are burned at high temperature, there is a risk that molten slag such as ash cannot be formed due to insufficient temperature. Absent. In addition, since the steam generated in the drying process does not contain combustible gas, it is not necessary to install a special combustion facility to process this steam,
It does not unnecessarily increase the construction cost of the waste treatment facility.

Steam generated from waste by indirect heating,
Alternatively, since the heating medium containing steam used in the direct heating method, direct heating method, and indirect heating combined method contains the odor component contained in the waste, remove the odor before releasing it into the atmosphere. Is desirable for environmental protection. At the inlet of the flue, the high temperature combustion exhaust gas immediately after the low temperature carbonization gas and the char are burned at a temperature at which the combustion residue becomes molten slag flows. Therefore, the introduced steam and odor components in the heating medium are burned by the high-temperature combustion exhaust gas to be deodorized, or converted into a substance that can be easily removed by an exhaust gas purification facility provided downstream of the flue (especially ammonia,
Aldehydes, amines, sulfides, mercaptans, etc.).
In the waste treatment technology as in the present invention, generally, a dust collection facility for removing dust particles in combustion exhaust gas and a gas purification facility for desulfurization, denitration, etc. are provided on the downstream side of the inlet of the flue. It is customary to Therefore, when such equipment is provided, the heating medium used for drying the waste by the direct heating method is also discharged into the atmosphere after being treated by the equipment. It is necessary to install a buffer container at the inlet of the flue in order to secure a sufficient residence time so that the deodorizing reaction can be performed at high temperature when introducing the steam or heating medium containing the odor to the inlet of the flue. There may be.

When the low temperature carbonization gas and the char are burned at a temperature at which the combustion residue becomes molten slag, the combustion temperature may become excessively high. In such a case, Japanese Patent Laid-Open No. 1-49816 discloses a technique of lowering the temperature inside the furnace by introducing low-temperature combustion exhaust gas flowing near the outlet of the flue to the burner of the combustion melting furnace by a conduit. ing. On the other hand, in the present invention, after drying the waste, by introducing a part of the heating medium containing steam or steam separated from the waste into the combustion atmosphere of the low-temperature carbonization gas and char, the combustion temperature is lowered and the excess high temperature is increased. 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 introduction amount of steam to be introduced and the heating medium containing the steam, the introduction amount and the like should be adjusted in consideration of various conditions such as temperature and water content. Yes. Further, when a gas containing oxygen such as air is used as the heating medium, it goes without saying that this participates in combustion in the combustor.
It is possible to control the combustion temperature by adjusting the amount introduced. At this time, the odorous components in the heating medium containing steam or steam introduced into the combustion atmosphere of the low-temperature carbonization gas and char are deodorized by being burned with the low-temperature carbonization gas or char, or the exhaust gas purification equipment in the flue downstream. Is converted into a substance that can be easily removed.

[0065]

According to the present invention, the waste is indirectly or directly heated with a heating medium to be dried, and the moisture in the waste is sufficiently removed, and then the waste is thermally decomposed. (EN) It is possible to provide a waste treatment device and method capable of preventing a situation in which a molten slag such as ash cannot be formed due to insufficient temperature in a combustion melting furnace.

[Brief description of the drawings]

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

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

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

[Explanation of symbols]

1, 26, 27 Dryer 3 Conveying device 4 Pyrolysis reactor 9 Combustion melting furnace 13 Flue 19, 31 Heating medium supply pipe 21a, 21b, 21c, 25a, 25b, 25c Conduit 22, 24, 33 Conduit 28a, 28b , 29a, 29b, 30 Conduit 35 Induced blower 36, 37, 38 Heat exchanger

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoki Yata No. 1 Yawata Kaigan Dori, Ichihara City, Chiba Mitsui Engineering & Shipbuilding Co., Ltd. (72) Norio Tezuka No. 1 Hachiman Kaigan Dori, Ichihara, Chiba Mitsui Engineering & Ships Co., Ltd. Chiba office

Claims (11)

[Claims] 1. A pyrolysis reactor that indirectly heats waste with a heating medium to pyrolyze it, and separates it into low-temperature dry distillation gas and pyrolysis residue; a char separated from the pyrolysis residue; In a waste treatment device provided with a combustor that combusts a low-temperature carbonization gas at a temperature at which a combustion residue can be molten and slagged, and a flue that discharges the combustion exhaust gas generated by this combustion to the outside air, A heat exchanger that is provided to indirectly exchange heat between the heating medium and the combustion exhaust gas, and means for guiding the heating medium from the heat exchanger to the thermal decomposition reactor,
A dryer that heats and dries the heating medium discharged from the pyrolysis reactor and the waste directly or indirectly to heat the waste to a temperature at which the waste can be dehydrated, and a dryer produced by this drying. And a means for discharging the steam or the heating medium containing the steam from the dryer. 2. A pyrolysis reactor that indirectly heats waste with a heating medium to pyrolyze it, and separates it into low-temperature carbonization gas and pyrolysis residue, a char separated from the pyrolysis residue, and the above-mentioned char. In the waste treatment device provided with a combustor that combusts a low-temperature carbonization gas at a temperature at which a combustion residue can be molten and slagged, and a flue that discharges the combustion exhaust gas generated by this combustion to the outside air, the thermal decomposition reactor Indirect heat exchange is performed between the heating medium and the waste product, and the waste product is heated to about 2
A dryer for heating and drying to a dehydrating temperature of 00 ° C. or less, a steam discharging means for discharging the steam generated by this drying to the outside of the dryer, and a waste after the drying for the thermal decomposition reactor. A waste processing apparatus, comprising: a transporting unit that transports and performs the thermal decomposition. 3. A pyrolysis reactor that indirectly heats waste with a heating medium to pyrolyze it and separates it into low-temperature dry distillation gas and pyrolysis residue, a char separated from the pyrolysis residue, and the above-mentioned char. In the waste treatment device provided with a combustor that combusts a low-temperature carbonization gas at a temperature at which a combustion residue can be molten and slagged, and a flue that discharges the combustion exhaust gas generated by this combustion to the outside air, the thermal decomposition reactor The heating medium discharged from the waste is brought into direct contact with the waste, the waste is heated to a temperature at which dehydration is possible at about 200 ° C. or less and dried, and the steam that is released from the waste by the drying is included. It is characterized by comprising heating medium discharging means for discharging the heating medium to the outside of the dryer, and conveying means for conveying the dried waste to the thermal decomposition reactor to perform the thermal decomposition. Waste treatment equipment. 4. A pyrolysis reactor that indirectly heats waste with a heating medium to pyrolyze it, and separates it into low-temperature carbonization gas and pyrolysis residue, a char separated from the pyrolysis residue, and the above-mentioned char. In the waste treatment device provided with a combustor that combusts a low-temperature carbonization gas at a temperature at which a combustion residue can be molten and slagged, and a flue that discharges the combustion exhaust gas generated by this combustion to the outside air, the thermal decomposition reactor Indirect heat exchange with the heating medium exiting the reactor and direct introduction of the heating medium exiting the pyrolysis reactor into the waste are carried out at the same time, and the waste is heated to approximately 200 ° C. or lower. A dryer for heating to a temperature at which it can be dehydrated and drying, steam / heating medium discharging means for discharging the steam generated from waste by this drying and the heating medium after the direct introduction to the outside of the dryer, and the drying After the waste is removed from the A waste treatment device, which is provided with a transporting means for transporting it to a reactor to perform the thermal decomposition. 5. The steam discharged from the steam discharge means, the heating medium discharge means, or the steam / heating medium discharge means and / or the heating medium is supplied to the flue gas outlet side of the combustion exhaust gas from the combustor, The waste treatment device according to any one of claims 1 to 4, further comprising: a discharge passage that leads into a container provided in the middle of the flue. 6. A temperature control means for controlling a temperature of the combustor by introducing a part of the heating medium and / or steam introduced into the discharge passage into the combustor. Item 5. The waste treatment device according to item 5. 7. A step of introducing waste into a pyrolysis reactor, indirectly heating it with a heating medium to pyrolyze it, and separating it into a low temperature carbonization gas and a pyrolysis residue, and from the pyrolysis residue. Disposal including a step of burning the separated char and the low-temperature carbonization gas at a temperature at which a combustion residue can be molten and slagged, and a step of introducing a combustion exhaust gas generated by this combustion to an outlet for discharging to the outside air by a flue. In the material treatment method, a step of indirectly exchanging heat between the heating medium that has exited from the thermal decomposition reactor and the waste, and heating the waste to a temperature at which dehydration is possible at approximately 200 ° C. or lower and drying. And a step of separating water vapor generated by this drying from the waste, and a step of transporting the dried waste to the pyrolysis reactor as pretreatment steps for the pyrolysis step. Waste treatment method characterized by Law. 8. A step of introducing wastes into a pyrolysis reactor and indirectly heating them with a heating medium to pyrolyze them to separate them into low-temperature carbonization gas and pyrolysis residue, and from the pyrolysis residue. Disposal including a step of burning the separated char and the low-temperature carbonization gas at a temperature at which a combustion residue can be molten and slagged, and a step of introducing a combustion exhaust gas generated by this combustion to an outlet for discharging to the outside air by a flue. In the material treatment method, the heating medium is brought into direct contact with the waste, the waste is heated to a temperature at which dehydration is possible at about 200 ° C. or less and dried, and steam generated from the waste by the drying. And a step of separating the heating medium directly introduced into the waste from the waste, and a step of conveying the dried waste to the pyrolysis reactor, a pretreatment step of the pyrolysis step To include as Characteristic waste treatment method. 9. A step of introducing waste into a pyrolysis reactor, indirectly heating it with a heating medium to pyrolyze it, and separating it into a low temperature carbonization gas and a pyrolysis residue, and from the pyrolysis residue. Disposal including a step of burning the separated char and the low-temperature carbonization gas at a temperature at which a combustion residue can be molten and slagged, and a step of introducing a combustion exhaust gas generated by this combustion to an outlet for discharging to the outside air by a flue. In the waste treatment method, indirect heat exchange between the waste and the heating medium exiting the thermal decomposition reactor and direct contact of the heating medium exiting the thermal decomposition reactor with the waste are performed. At the same time, the waste is
A step of drying by heating to a temperature capable of dehydration of approximately 200 ° C. or lower, and a step of separating from the waste the steam generated from the waste by the drying and the heating medium directly introduced into the waste. And a step of transporting the dried waste to the thermal decomposition reactor as a pretreatment step of the thermal decomposition step. 10. The flue of the separated steam and / or heating medium on the exhaust gas outlet side from the combustor,
Or a step of introducing the steam into the container provided in the middle of the flue and deodorizing the separated steam and / or the heating medium by heating and deodorizing. Waste treatment method. 11. The step of burning the char and the low-temperature carbonization gas is carried out by introducing a part of the separated steam and heating medium into the combustion atmosphere to burn the char and the low-temperature carbonization gas. The waste treatment method according to claim 10, wherein the combustion temperature is controlled.