JPH0849820A - Waste treatment device and method - Google Patents

Abstract

(57) [Abstract] [Purpose] Waste treatment technology that thermally decomposes waste and converts the thermal energy generated by burning the thermal decomposition product to electric power to recover it. In addition, the direct heating type thermal decomposition using the partial combustion gas of the low-temperature carbonization gas as the heat source can be realized without any trouble in recovering the valuable substances in the waste in the unoxidized state and without the risk of explosion. [Structure] A part of the low-temperature carbonization gas produced in the thermal decomposition reactor 2 is introduced into a burner 9 through a low-temperature carbonization gas branch pipe 7. An air supply pipe 12 is connected to the burner 9, and this low temperature carbonization gas is burned with air or oxygen-containing gas. The oxygen concentration of the generated combustion exhaust gas is detected by an oxygen concentration meter.
Based on this detected value, the low-temperature carbonization gas or the amount of air or oxygen-containing gas introduced into the burner 9 is adjusted, and depending on the introduced air or oxygen-containing gas, the amount of oxygen that allows the low-temperature carbonization gas to be stoichiometrically completely burned. Adjust as follows. In this way, the combustion exhaust gas without residual oxygen is directly introduced into the waste in the thermal decomposition reactor 2 through the combustion exhaust gas supply pipe 16.

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 converting thermal energy generated by burning pyrolysis products into electric power and recovering the same.

[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 thermal energy.

Further, when the pyrolysis products are burned, the combustion residue such as ash is melted into slag at a high temperature (for example, 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 00 ° C or higher). In this case, an inorganic harmful substance such as a heavy metal oxide generated by combustion can be enclosed and processed in the form of an ash-melted solidified product without fear 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.

There are various conceivable thermal decomposition techniques for waste in such a waste treatment technique, and in many cases, how to construct the waste thermal decomposition technique depends on the thermal decomposition residue that is produced after the thermal decomposition process. It has a great influence on the separation process and the combustion process of char separated from low temperature carbonization gas and pyrolysis residue. For example, in the fractionation step, difficulty in fractionation due to inclusion of tar-like by-products may occur under unfavorable conditions. Further, in the combustion process, it is possible that there is a significant change in the temperature inside the combustion furnace or that the ash melting temperature (about 1200 ° C. or higher) is not reached under adverse conditions.

In the above-described conventional waste treatment technology, the thermal decomposition technology of waste materials uses two types, a direct heating method and an indirect heating method. Conventionally, as an indirect heating method in which a heat transfer medium (air, etc.) is circulated to a heat transfer tube provided in the pyrolysis reactor or the jacket of the outer wall of the pyrolysis reactor to exchange heat with waste, flue gas waste heat has been used. There is a technique for indirect heating by self-sufficiency using US Pat.
64, German Patent Publication No. 3815187A1, European Patent Publication No. 0340537B1 etc.). Further, as a direct heating method in which a heating medium (air or the like) is directly introduced into the pyrolysis reactor and the low temperature carbonization gas generated by the thermal decomposition of waste is partially burned to heat it, European Patent Publication No. There is 0360052A1.

[0007]

However, in the above-described self-contained indirect heating method, a heat exchanger for heating a heat medium such as air is often caused by a high-temperature flue gas containing hydrogen chloride and a large amount of fly ash. However, there is a problem in that it is very expensive to manufacture a heat exchanger using a material that can withstand such corrosion. In the indirect heating method, in addition to the self-contained indirect heating method described above,
It is conceivable to supply the heat medium from outside the system instead of self-sufficiency, but in this case, it is still expensive as it requires a separate heat source and auxiliary equipment outside the system. .

Further, in the indirect heating method, generally, the temperature of the heat medium as a heat source needs to be about 500 ° C. or higher. Therefore, a gas such as air must be used as the heat medium, and accordingly, both the thermal decomposition reactor and the heat exchanger for heating the heat medium must use the gas / gas heat exchanger. As is well known, the heat transfer efficiency of this type of heat exchanger is poor, so that the heat transfer area must be made very large, and the residence time of the waste in the thermal decomposition reactor must be lengthened. There is also.

On the other hand, in the direct heating method, the heat transfer efficiency is improved as compared with the indirect heating method. Further, for example, if a means for branching the flue gas and guiding it to the pyrolysis reactor and introducing it directly into the waste in the pyrolysis reactor requires a heat source outside the system, etc. Disappears.

However, the flue gas generally contains a considerable amount of residual oxygen as a result of the supply of air in excess of the stoichiometric amount required for combustion. In order to suitably perform the above-mentioned thermal decomposition step, it is necessary to perform it in an oxygen-free atmosphere, so it is difficult to use the direct heating method in which the flue gas is directly introduced into the waste. In addition, the flue gas contains a large amount of soot and dust, and when the flue gas is guided to the thermal decomposition reactor by the blower, the blower is overloaded. In addition, flue gas, which generally contains corrosive components (such as HCl), must be cooled to a temperature that the materials currently used for blowers can withstand before being introduced into the pyrolysis reactor. A large amount of relatively low-temperature flue gas is mixed in the low-temperature carbonization gas generated by the above in terms of heat balance, and the combustion temperature in the combustion process of char separated from the low-temperature carbonization gas and the thermal decomposition residue after the thermal decomposition process is It will be greatly reduced. This temperature decrease is a very disadvantageous factor when melting the ash in the combustion furnace, converting it into slag and taking it out (generally about 1200 ° C. or higher, preferably about 1300 ° C.).

The above-mentioned European Patent Publication No. 0360
According to the technology disclosed in 052A1, such a disadvantage can be avoided. That is, in the same publication, an air introduction pipe for introducing air into the pyrolysis reactor is provided, and a burner is provided in the pyrolysis reactor, and low temperature dry distillation is performed in the pyrolysis reactor to generate in the pyrolysis reactor. A part of the gas is burned and the combustion heat is used to perform thermal decomposition.

According to such a technique, the direct heating method can be realized while avoiding the disadvantages of the technique of directly introducing the flue gas into the pyrolysis reactor. Moreover, the heat source is the low-temperature carbonization gas generated in the thermal decomposition reactor, and the heat for thermal decomposition can be self-supplied without requiring a separate heat source outside the system.

However, in spite of the fact that the thermal decomposition can be satisfactorily carried out in a reducing atmosphere in which oxygen does not exist, according to the technique, it is necessary to stably maintain the partial combustion of the low-temperature carbonization gas, so that an excessive amount of the thermal decomposition is required. Tends to supply air. Therefore, the amount of oxygen remaining in the thermal decomposition reactor becomes large, and the combustion of the waste occurs instead of the thermal decomposition of the waste. Further, at this time, the non-combustible solid substance in the waste is oxidized, which is also a problem when it is desired to recover valuable substances such as aluminum and copper in an unoxidized state. Also, if the burner flame disappears unexpectedly, a large amount of oxygen fills the pyrolysis reactor together with the combustible low-temperature carbonization gas, increasing the risk of explosion.

The present invention relates to a waste treatment technique of thermally decomposing waste, converting the thermal energy generated by burning the thermally decomposed product into electric power, etc., and recovering it, and the thermal decomposition of the waste can be carried out well. The object of the present invention is to realize a direct heating type thermal decomposition using low-temperature carbonization gas as a heat source, which does not hinder the recovery of valuable substances in waste in an unoxidized state and does not pose a risk of explosion.

[0015]

A thermal decomposition reactor for heating and thermally decomposing waste to separate it into a low temperature carbonization gas and a thermal decomposition residue mainly composed of non-volatile components, and a fractionation from the thermal decomposition residue. In a waste treatment device comprising a char and a first combustor for burning the low-temperature carbonization gas,
1st invention for solving the said subject WHEREIN: The low-temperature carbonization gas introduction path which introduce | transduces a part of said low-temperature carbonization gas after the production | generation, and the said low-temperature carbonization gas which was introduce | transduced to this introduction path are air and / or oxygen-containing. A second combustor that burns with gas, a combustion air introduction path that introduces the air and / or an oxygen-containing gas into the second combustor, and a combustion exhaust gas generated by combustion by the second combustor are described above. A combustion exhaust gas introduction path that is directly introduced into the pyrolysis reactor and serves as the heating source of the pyrolysis reactor, and an oxygen concentration that detects the oxygen concentration in the combustion exhaust gas before being introduced into the pyrolysis reactor. And a low-temperature carbonization gas flow rate control means for controlling the flow rate of the low-temperature carbonization gas flowing through the low-temperature carbonization gas introduction path based on the detected oxygen concentration and suppressing the amount of oxygen in the combustion exhaust gas. Waste treatment equipment characterized by It is.

A first low-temperature carbonization gas introduction path for guiding a part of the low-temperature carbonization gas after the generation and a first low-temperature carbonization gas introduced into the introduction path are burned with air and / or oxygen-containing gas. No. 2 combustor, a combustion air introducing passage for introducing the air and / or the oxygen-containing gas to the second combustor, and a combustion exhaust gas generated by combustion by the second combustor in the pyrolysis reactor. Directly into the thermal decomposition reactor, the combustion exhaust gas introduction path to be the heating source, an oxygen concentration meter for detecting the oxygen concentration in the combustion exhaust gas before being introduced into the thermal decomposition reactor, A second low temperature carbonization gas introduction path for guiding a part of the generated low temperature carbonization gas other than the one flowing through the low temperature carbonization gas introduction path to the first low temperature carbonization gas introduction path; The second low temperature dry based on the oxygen concentration detected by the densitometer. A low-temperature carbonization gas flow rate adjusting means for controlling the flow rate of the low-temperature carbonization gas flowing through the gas introduction passage and suppressing the amount of oxygen in the combustion exhaust gas is provided as a second waste treatment device. Invented.

A low-temperature carbonization gas introducing passage for guiding a part of the generated low-temperature carbonization gas, and a second combustor for combusting the low-temperature carbonization gas introduced into the introduction passage with air and / or oxygen-containing gas. , A combustion air introduction path for introducing the air and / or an oxygen-containing gas to the second combustor, and a combustion exhaust gas generated by combustion by the second combustor are directly introduced into the pyrolysis reactor, A combustion exhaust gas introduction path to be the heating source of the thermal decomposition reactor, an oxygen concentration meter for detecting the oxygen concentration in the combustion exhaust gas before being introduced into the thermal decomposition reactor, and oxygen detected by the oxygen concentration meter. Air flowing through the combustion air introduction path based on the concentration, and or, the flow rate of the oxygen-containing gas is adjusted, and a combustion air flow rate adjusting means for suppressing the amount of oxygen in the combustion exhaust gas is provided. Third waste treatment device Invention that.

Further, a step of heating and thermally decomposing the waste to separate it into a low temperature carbonization gas and a thermal decomposition residue mainly composed of non-volatile components, and a char separated from the thermal decomposition residue and the low temperature carbonization gas. And a step of burning a part of the low-temperature carbonization gas after the production, and burning the extracted low-temperature carbonization gas with air and / or an oxygen-containing gas. And a step of directly introducing the combustion exhaust gas generated by the combustion step of a part of the low-temperature carbonization gas into the thermal decomposition reactor to use it as the heating source of the thermal decomposition reactor, and introducing it into the thermal decomposition reactor. Detecting the oxygen concentration in the combustion exhaust gas before
A fourth step of adjusting the amount of low-temperature carbonization gas taken out in the low-temperature carbonization gas extraction step based on the detected oxygen concentration to suppress the amount of oxygen in the combustion exhaust gas. Invention.

A step of taking out a part of the low temperature carbonization gas after the generation, and the taken out low temperature carbonization gas to air;
Alternatively, a step of burning with an oxygen-containing gas, a step of directly introducing the combustion exhaust gas generated by the burning step of a part of the low-temperature carbonization gas into the thermal decomposition reactor, and the heating source of the thermal decomposition reactor, Part of the low-temperature carbonization gas after the production, which is different from the step of detecting the oxygen concentration in the combustion exhaust gas before being introduced into the pyrolysis reactor, and the part taken out in the part-gas removal step of the low-temperature carbonization gas Of the low temperature carbonization gas introduced in the combustion exhaust gas introduction step based on the detected oxygen concentration, and a step of suppressing the oxygen amount in the combustion exhaust gas. A waste treatment method characterized by the above is defined as a fifth invention.

A step of taking out a part of the low temperature carbonization gas after the generation, and the taken out low temperature carbonization gas to air;
Alternatively, a step of burning with an oxygen-containing gas, a step of directly introducing the combustion exhaust gas generated in this burning step into the pyrolysis reactor, and using it as the heating source of the pyrolysis reactor, and introducing into the pyrolysis reactor Before the step of detecting the oxygen concentration in the combustion exhaust gas, and adjusting the air and or oxygen-containing gas amount based on the detected oxygen concentration, the step of suppressing the oxygen amount in the combustion exhaust gas. A sixth aspect of the present invention is a waste treatment method characterized by including the above.

[0021]

According to the first or fourth aspect of the invention, a part of the low-temperature carbonization gas produced in the pyrolysis reactor is combusted with air and / or an oxygen-containing gas to produce a combustion exhaust gas, and the combustion after the production is carried out. The exhaust gas is directly introduced into the pyrolysis reactor. Then, since the oxygen concentration in the combustion exhaust gas is detected before being introduced into the pyrolysis reactor, the amount of low-temperature carbonization gas used as the heat source of the pyrolysis reactor is adjusted based on the detected oxygen concentration,
It is possible to suppress the amount of oxygen in the combustion exhaust gas introduced into the pyrolysis reactor. Therefore, the thermal decomposition of the waste can be favorably performed, and it is possible to realize the thermal decomposition of the direct heating system using the low-temperature carbonization gas as the heat source without any trouble in recovering the valuable substances in the waste in the unoxidized state. . Furthermore, since the second combustion chamber is separated from the pyrolysis reactor, it is much safer in terms of explosion protection than partial combustion inside the pyrolysis reactor itself.

Even if it is configured as in the second or fifth invention,
The same operation as that of the first or fourth invention can be achieved. In the case of the present invention, a part of the low-temperature carbonization gas is burned with an amount of oxygen which is stoichiometrically completely combusted, and the residual oxygen in the combustion exhaust gas by this is consumed by adding the low-temperature carbonization gas. Since it is possible to suppress, it is possible to suppress the situation that the flame is extinguished unexpectedly, which tends to occur during incomplete combustion, and it is possible to maintain stable combustion. In addition, by increasing the amount of low-temperature carbonization gas that is further added to suppress the residual oxygen in the combustion exhaust gas, the temperature of the combustion exhaust gas to which the additional low-temperature carbonization gas is added can be lowered (and discarded). (The amount of heat supplied to the material does not decrease), and thermal damage to the thermal decomposition reactor and the combustion exhaust gas introduction passage for supplying combustion exhaust gas to the thermal decomposition reactor can be mitigated.

According to the third or sixth invention, the amount of oxygen in the combustion exhaust gas introduced into the thermal decomposition reactor is adjusted by adjusting the amount of air and / or oxygen-containing gas based on the detected oxygen concentration. It can be suppressed, and the same operation as that of the first or fourth invention is achieved.

It is needless to say that in any of the inventions, it is desirable to suppress the amount of oxygen so that the combustion exhaust gas becomes almost oxygen-free. That is, in the first, third, fourth, or sixth invention, depending on the supplied air and / or oxygen-containing gas, the low-temperature carbonization gas is stoichiometrically at a low temperature such that it is equal to or less than the amount of oxygen that allows complete combustion. It is desirable to control the amount of dry distillation gas and the amount of air and / or oxygen-containing gas. In the second or fifth aspect of the invention, the amount of low-temperature carbonization gas is adjusted so that the amount of oxygen exceeds stoichiometrically complete combustion, or the amount of low-temperature carbonization gas is adjusted to a value that allows stable combustion without extinguishing the fire. However, the amount of the low-temperature carbonization gas to be added is equal to or larger than the amount that can completely consume the residual oxygen in the combustion exhaust gas, or the pyrolysis reactor or the combustion exhaust gas introduction path for supplying the combustion exhaust gas to this pyrolysis reactor. It is desirable that the amount be equal to or more than the amount that can avoid thermal damage.

[0025]

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 an embodiment of the present invention. Reference numeral 1 is a waste supply device for supplying waste to the thermal decomposition reactor 2. As the thermal decomposition reactor 2, a horizontal rotary drum (rotary kiln), a vertical shaft kiln, etc. have been conventionally used, but the former is used in consideration of the retention time of waste in the thermal decomposition reactor 2. Is desirable.

FIG. 2 is a system diagram showing an example of the main part of this embodiment. The thermal decomposition reactor 2 rotates at about 300 to 900 ° C. while rotating as shown by an arrow 15, and at a temperature of about 300 to 600 ° C. in order to take out aluminum or the like from the thermal decomposition residue as a valuable resource in the unmelted state, the waste 100 Is pyrolyzed by heating to produce a low temperature carbonization gas and mainly a non-volatile pyrolysis residue. Reference numeral 3 denotes a carry-out device, and the pyrolysis residue is carried by a pyrolysis residue carrying device 5 provided on the bottom side of the carry-out device 3 and guided to a residue separating device 51. The low-temperature carbonization gas is supplied from a low-temperature carbonization gas discharge pipe 4 provided on the upper side of the carry-out device 3 and partly through a blower 8, and a low-temperature carbonization gas branch pipe 7 is provided as an example of the low-temperature carbonization gas introduction path in the present invention. Is led to the burner 9 and the rest is led to the burner 50 of the combustion furnace 55 by the low temperature carbonization gas conduit 6.

The burner 9 is a burner provided in the combustor 11 as an example of the second combustor in the present invention.
An air supply pipe 12 as an example of a combustion air introduction passage in the present invention is connected to the burner 9, and air or oxygen-containing gas is supplied to the burner 9 by an air compressor 13. In the combustor 11, the low-temperature carbonization gas introduced by the low-temperature carbonization gas branch pipe 7 is burned by the burner 9 with air or oxygen-containing gas. Reference numeral 16 is a combustion exhaust gas supply pipe as an example of the combustion exhaust gas introduction passage in the present invention. This tube 16
The combustor 11 and the thermal decomposition reactor 2 are connected to each other, the combustion exhaust gas from the combustor 11 is directly introduced into the thermal decomposition reactor 2, and the waste 100 is heated as a heating source of the thermal decomposition reactor 2. .

An oxygen concentration meter 17 is provided in the combustion exhaust gas supply pipe 16 to detect the oxygen concentration in the combustion exhaust gas before being introduced into the thermal decomposition reactor 2. This detected oxygen concentration signal is input to the controller 18. The controller 18 outputs a control signal to a control valve 19 provided in the low temperature carbonization gas branch pipe 7. The controller 18 and the control valve 19 constitute an example of the low-temperature carbonization gas flow rate adjusting means in the present invention, and the low-temperature carbonization gas flowing through the low-temperature carbonization gas branch pipe 7 based on the oxygen concentration detected by the oxygen concentration meter 17 The flow rate is adjusted to suppress the amount of oxygen in the combustion exhaust gas introduced into the pyrolysis reactor 2. Since it is desirable to suppress the oxygen content so that the combustion exhaust gas becomes almost oxygen-free, depending on the air or oxygen-containing gas, the low-temperature carbonization gas is stoichiometrically less than or equal to the oxygen quantity at which complete combustion is possible. Low temperature carbonization gas branch pipe 7
It is desirable to control the amount of low-temperature carbonization gas introduced in (1).

FIG. 3 is a system diagram showing another example of the main part of this embodiment. 2 are the same as those in the example shown in FIG. 2, and detailed description thereof will be omitted. The difference of the example shown in FIG. 3 from the case of FIG. 2 is as follows.
First, the low-temperature carbonization gas branch pipe 7 serves as a first low-temperature carbonization gas branch pipe 20 as an example of the first low-temperature carbonization gas introduction passage of the present invention, and as an example of the second low-temperature carbonization gas introduction passage of the present invention. To the second low-temperature carbonization gas branch pipe 21 of the above. The first low-temperature carbonization gas branch pipe 20 is connected to the burner 9, and the second low-temperature carbonization gas branch pipe 21 is connected to the downstream side of the flame of the burner 9 in the combustor 11. Blowers 22 and 23 are provided in the first and second low-temperature carbonization gas branch pipes 20 and 21, respectively, instead of the blower 8, and the first and second low-temperature carbonization gas branch pipes 21 are respectively replaced in place of the control valve 19. Control valves 24 and 25 are provided in the.
The detection signal of the oximeter 17 is input to the controller 26, and the controller 26 outputs the control signal to the control valves 24 and 25. The controller 26 and the control valves 24 and 25 are an example of the low-temperature carbonization gas flow rate control means in the present invention.

The controller 26 controls the regulating valve 24 so that the first valve
The amount of the low temperature carbonization gas flowing through the low temperature carbonization gas branch pipe 20 is adjusted. Since the combustion exhaust gas generated by the combustion of the low-temperature carbonization gas in the burner 9 flows to the downstream side of the flame of the burner 9, the control valve 25 is controlled by the controller 26, and a predetermined amount of other low-temperature carbonization gas is burned. Gas is supplied to consume the residual oxygen in the combustion exhaust gas that has flowed to the downstream side of the flame of the burner 9,
The amount of residual oxygen in the combustion exhaust gas introduced into the thermal decomposition reactor 2 is suppressed. It is desirable to suppress the residual oxygen amount so that the combustion exhaust gas is in a substantially oxygen-free state. Therefore, the amount of air or oxygen-containing gas supplied through the air supply pipe 12 is greater than the amount of oxygen that can stoichiometrically completely burn the low-temperature carbonization gas supplied by the first low-temperature carbonization gas branch pipe 20. The amount of the low temperature carbonization gas supplied via the second low temperature carbonization gas branch pipe 21 is controlled by controlling the regulating valve 24 so that the amount of oxygen keeps burning stably without extinguishing the fire. The control valve 25 is arranged so that the amount of residual oxygen in the combustion exhaust gas generated in the reactor 11 is set to an amount that can be completely consumed or more.
It is desirable to control

As a modified example of the example shown in FIG. 2, a regulating valve 19 may be provided in the air supply pipe 12 so as to regulate the flow rate of air or oxygen-containing gas instead of the low temperature dry distillation gas flow rate. . Also in this case, it is desirable to suppress the oxygen amount so that the combustion exhaust gas is in a substantially oxygen-free state. Therefore, the air supply pipe 12 is controlled so that the low-temperature carbonization gas is stoichiometrically less than or equal to the oxygen amount capable of complete combustion. It is desirable to control the amount of air and oxygen-containing gas introduced by.

In any of the above-mentioned examples, the predetermined temperature is maintained in the pyrolysis reactor and the required amount of heat for pyrolysis is supplied in consideration of the properties of the untreated waste (heat generation amount, water content, incombustible amount, etc.). It is desirable to adjust it. Further, for example, when the amount of heat is insufficient in the thermal decomposition step or the combustion step of the remaining low-temperature carbonization gas by the burner 50 after this step, as in the case where the waste contains too much water, Alternatively, the auxiliary combustion fuel may be added separately from outside the system. Alternatively, the oxygen concentration in the air or oxygen-containing gas used for combustion may be increased or indirectly heated before being used for combustion.

The residue separating device 51 is composed of, for example, a sieve, and separates the pyrolysis residue into rubble, aluminum, iron, etc. and char. The separated char is introduced into the burner 50 by the conduit 52. The burner 50 is the burner of the combustion furnace 55, and the combustion air is also supplied from the ventilation pipe 53 by the air compressor 54. In the combustion furnace 55, the combustion air burns the low-temperature carbonization gas and char. In this case, it burns at a high temperature under relatively low air ratio conditions (temperature is 1200 ° C
Approximately more, preferably about 1300 ℃) melting ash,
It is also possible to drop it from the bottom of the combustion furnace 55 into a cooling water tank 56 for rapid cooling and take it out as slag. In addition, in the char combustion, a char blowing port may be provided separately from the burner 50 to blow the flame from the burner 50.

Reference numeral 57 is an exhaust heat boiler, which obtains high-temperature steam by exchanging heat with the combustion exhaust gas introduced through a conduit 58. This high temperature steam is guided to the conduit 60 and used for power generation or the like in the turbine 59 or the like. The flue gas after heat exchange in the exhaust heat boiler 57 is guided to the conduit 61 to remove ash in the dust collector 62, and is introduced to the flue gas purifying device 64 in the conduit 63 for purification (dehydrochlorination, desulfurization, denitration, etc.). ), Is guided to the conduit 65, and is discharged from the chimney 66. It is desirable that the ash removed by the dust collector 62 be returned to the combustion furnace 55 by the line 68. 67 is an exhaust gas induction blower.

Next, the operation of this embodiment will be described. In this example, a part of the low-temperature carbonized gas produced in the pyrolysis reactor 2 is burned with air and / or an oxygen-containing gas to produce a combustion exhaust gas, and the produced combustion exhaust gas is produced in the pyrolysis reactor 2. It is configured such that the waste 100 is heated by directly introducing it into the. Since the oxygen concentration in the combustion exhaust gas is detected before being introduced into the thermal decomposition reactor 2, the amount of low-temperature carbonization gas (or air or the amount of air or the like) used as a heat source of the thermal decomposition reactor 2 is detected based on the detected oxygen concentration. The amount of oxygen gas) can be adjusted to suppress the amount of oxygen in the combustion exhaust gas introduced into the thermal decomposition reactor 2. Therefore, the thermal decomposition of the waste 100 can be performed favorably, and there is no problem in recovering the valuables in the waste 100 in an unoxidized state, and the thermal decomposition of the direct heating system using the partial combustion gas of the low-temperature carbonization gas as the heat source. Can be realized.

In the example shown in FIG. 3, a portion of the low-temperature carbonized gas is stoichiometrically completely burned, or is burned with an amount of oxygen that continues to burn stably without extinguishing the fire, and combustion exhaust gas resulting from this is burned. Since residual oxygen in the inside can be consumed and suppressed by adding a low temperature carbonization gas,
It is possible to suppress a situation where the flame disappears unexpectedly, which often occurs during incomplete combustion, and it is possible to maintain stable combustion. In addition, by increasing the amount of low-temperature carbonization gas that is further added to suppress the residual oxygen in the combustion exhaust gas, the temperature of the combustion exhaust gas to which the additional low-temperature carbonization gas is added can be lowered (and discarded). (The amount of heat supplied to the product 100 does not decrease), and thermal damage to the thermal decomposition reactor 2 and the combustion exhaust gas supply pipe 16 that supplies combustion exhaust gas to the thermal decomposition reactor 2 can be mitigated.

[0037]

According to the present invention described above, the waste treatment technology for thermally decomposing waste and converting the heat energy generated by burning the pyrolysis product into electric power and recovering the same is described as waste treatment. Thermal decomposition of the low temperature carbonization gas partial combustion gas is used as the heat source for the thermal decomposition of the waste, which does not hinder the recovery of valuable substances in the waste in the unoxidized state and does not cause an explosion. The purpose is to realize.

[Brief description of drawings]

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

FIG. 2 is a system diagram showing an example of a main part of a waste treatment device according to an embodiment of the present invention.

FIG. 3 is a system diagram showing another example of the main part of the waste treatment apparatus which is an embodiment of the present invention.

[Explanation of symbols]

 2 Pyrolysis reactor 7 Low temperature dry distillation gas branch pipe 9 Burner 11 Combustor 12 Air supply pipe 16 Combustion exhaust gas supply pipe 17 Oxygen concentration meter 18, 26 Controller 19, 24, 25 Control valve 20 First low temperature dry distillation gas branch pipe 21 Second low-temperature carbonization gas branch pipe 100 Waste

Claims (6)

[Claims] 1. A pyrolysis reactor for heating and thermally decomposing waste to separate it into a low-temperature dry distillation gas and a pyrolysis residue mainly consisting of non-volatile components, a char separated from the pyrolysis residue, and the above-mentioned char. In a waste treatment device including a first combustor that burns a low-temperature carbonization gas, a low-temperature carbonization gas introduction path that guides a part of the low-temperature carbonization gas that has been generated, and the above-described introduction path that is introduced to the introduction path. A second combustor for combusting the low-temperature carbonization gas with air and / or an oxygen-containing gas; a combustion air introduction path for introducing the air and / or the oxygen-containing gas into the second combustor; Combustion exhaust gas produced by combustion by a combustor is directly introduced into the pyrolysis reactor, and a combustion exhaust gas introduction path that serves as the heating source of the pyrolysis reactor, and the combustion before being introduced into the pyrolysis reactor Oxygen for detecting oxygen concentration in exhaust gas And a low-temperature carbonization gas flow rate adjusting means for suppressing the amount of oxygen in the combustion exhaust gas by adjusting the flow rate of the low-temperature carbonization gas flowing through the low-temperature carbonization gas introduction path based on the detected oxygen concentration. Waste treatment equipment characterized by being 2. A thermal decomposition reactor for heating and thermally decomposing waste to separate it into a low-temperature dry distillation gas and a thermal decomposition residue mainly composed of non-volatile components, a char separated from the thermal decomposition residue, and the above-mentioned char. In a waste treatment device including a first combustor that burns a low-temperature carbonization gas, a first low-temperature carbonization gas introduction path for guiding a part of the low-temperature carbonization gas after the generation, and a first low-temperature carbonization gas introduction path for introducing the low-temperature carbonization gas to the introduction path. A second combustor for combusting the formed low-temperature carbonized gas with air and / or an oxygen-containing gas; a combustion air introduction path for introducing the air and / or the oxygen-containing gas into the second combustor; A combustion exhaust gas introduction path for directly introducing the combustion exhaust gas generated by the combustion by the second combustor into the thermal decomposition reactor to serve as the heating source of the thermal decomposition reactor, and before being introduced into the thermal decomposition reactor. Detecting the oxygen concentration in the combustion exhaust gas of An oxygen concentration meter and a second low temperature carbonization gas which introduces a part of the generated low temperature carbonization gas, which is different from the amount flowing through the first low temperature carbonization gas introduction path, into the first low temperature carbonization gas introduction path. Low-temperature carbonization for suppressing the amount of oxygen in the combustion exhaust gas by adjusting the flow rate of the low-temperature carbonization gas flowing in the second low-temperature carbonization gas introduction channel based on the gas introduction path and the oxygen concentration detected by the oxygen concentration meter. A waste treatment apparatus, comprising: a gas flow rate adjusting means. 3. A thermal decomposition reactor for heating and thermally decomposing waste to separate it into a low-temperature dry distillation gas and a thermal decomposition residue mainly composed of non-volatile components, a char separated from the thermal decomposition residue, and the above-mentioned char. In a waste treatment device including a first combustor that burns a low-temperature carbonization gas, a low-temperature carbonization gas introduction path that guides a part of the low-temperature carbonization gas that has been generated, and the above-described introduction path that is introduced to the introduction path. A second combustor for combusting the low-temperature carbonization gas with air and / or an oxygen-containing gas; a combustion air introduction path for introducing the air and / or the oxygen-containing gas into the second combustor; Combustion exhaust gas produced by combustion by a combustor is directly introduced into the pyrolysis reactor, and a combustion exhaust gas introduction path that serves as the heating source of the pyrolysis reactor, and the combustion before being introduced into the pyrolysis reactor Oxygen for detecting oxygen concentration in exhaust gas Adjust the degree meter, air flowing through the combustion air introduction passage based on the detection of oxygen concentration by the oxygen concentration meter and, or the flow rate of the oxygen-containing gas,
A waste treatment apparatus, comprising: a combustion air flow rate control unit that suppresses the amount of oxygen in the combustion exhaust gas. 4. A step of heating and thermally decomposing waste to separate it into a low-temperature dry distillation gas and a pyrolysis residue mainly composed of non-volatile components, and char separated from the pyrolysis residue and the low-temperature dry distillation gas. In the waste treatment method including the step of burning and, a step of extracting a part of the low-temperature carbonization gas after the production, and a step of burning the extracted low-temperature carbonization gas with air and / or oxygen-containing gas And a step of directly introducing the combustion exhaust gas generated by the step of burning a part of the low-temperature carbonization gas into the pyrolysis reactor, and using it as the heating source of the pyrolysis reactor,
A step of detecting the oxygen concentration in the combustion exhaust gas before being introduced into the thermal decomposition reactor, and adjusting the extraction amount of the low-temperature carbonization gas in the low-temperature carbonization gas extraction step based on the detected oxygen concentration, the combustion And a step of suppressing the amount of oxygen in the exhaust gas. 5. A step of heating and thermally decomposing the waste to separate it into a low temperature carbonization gas and a thermal decomposition residue mainly composed of non-volatile components, and char separated from the thermal decomposition residue and the low temperature carbonization gas. In the waste treatment method including the step of burning and, a step of extracting a part of the low-temperature carbonization gas after the production, and a step of burning the extracted low-temperature carbonization gas with air and / or oxygen-containing gas And a step of directly introducing the combustion exhaust gas generated by the step of burning a part of the low-temperature carbonization gas into the pyrolysis reactor, and using it as the heating source of the pyrolysis reactor,
Part of the low-temperature carbonization gas after the production, which is different from the step of detecting the oxygen concentration in the combustion exhaust gas before being introduced into the pyrolysis reactor, and the part taken out in the part-gas removal step of the low-temperature carbonization gas Of the low temperature carbonization gas introduced in the combustion exhaust gas introduction step based on the detected oxygen concentration, and a step of suppressing the oxygen amount in the combustion exhaust gas. A waste treatment method characterized by the above. 6. A step of heating and thermally decomposing the waste to separate it into a low-temperature dry distillation gas and a pyrolysis residue mainly consisting of non-volatile components, and char separated from the pyrolysis residue and the low-temperature dry distillation gas. In the waste treatment method including the step of burning and, a step of extracting a part of the low-temperature carbonization gas after the production, and a step of burning the extracted low-temperature carbonization gas with air and / or oxygen-containing gas And a step of directly introducing the combustion exhaust gas generated in this combustion step into the thermal decomposition reactor to make the heating source of the thermal decomposition reactor, and the combustion exhaust gas before being introduced into the thermal decomposition reactor. And a step of detecting the oxygen concentration of the air and / or adjusting the amount of oxygen-containing gas based on the detected oxygen concentration, and suppressing the amount of oxygen in the combustion exhaust gas. Waste treatment Law.