JPH0849821A - Device and method for treating waste - Google Patents

Abstract

PURPOSE:To provide the waste treating technology, higher in a power generating efficiency than conventional super waste power generating technology, by a method wherein a direct heating system, self supplying the heat of thermal decomposition by burning a part of low-temperature distillation gas produced by the thermal decomposition is employed in the waste treating technology, in which the thermal decomposition of the waste is carried out heat energy produced by burning the products of the thermal decomposition is converted into an electric power to recover it. CONSTITUTION:A combustor 11 burns a part of low-temperature distillation gas produced in a thermal decomposition reactor 2, employing a part of waste gas of combustion of another combustor 35 after driving a gas turbine 29 as combustion air. The waste gas of combustion is introduced directly into wastes in thermal decomposition reactor 2 through a combustion waste gas supplying tube 16 and is used for a heat source for effecting the thermal decomposition of the waste. The combustion waste gas of the combustor 35 is employed for the combustion air of the other combustor 55. Accordingly, the combustion waste gas after driving the gas turbine 29 is changed into high-temperature combustion waste gas by the combustion of the final combustor 55 and is used as the heat source of production of steam for driving a steam power generator 50 as it is.

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 collecting the electric power.

[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 drives a steam generator to generate electricity and recover heat 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.

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 of directly introducing air into the pyrolysis reactor to partially combust the low-temperature carbonization gas in the pyrolysis reactor and thereby heat the waste, European Patent Publication N
o. There is 0360052A1.

However, in the above-mentioned self-contained indirect heating method, the heat exchanger for heating the heating medium such as air is often corroded by the high temperature flue gas containing hydrogen chloride and a large amount of fly ash derived from the waste. Therefore, 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 as described above, it is also possible to supply the heat medium from outside the system rather than in a self-sufficient manner. However, since it is necessary to provide an auxiliary equipment and an auxiliary facility, the cost is still high.

Further, in the indirect heating system, 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 more than the stoichiometrically required amount of air 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 and the waste is heated. 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. Furthermore, the flue gas after being cooled to a temperature that the materials currently used for blowers can withstand must be introduced into the pyrolysis reactor, which relatively reduces the low-temperature carbonization gas produced by pyrolysis. A large amount of low-temperature flue gas is mixed in, and the combustion temperature is greatly reduced in the combustion process of char separated from the low-temperature carbonization gas and the pyrolysis residue after the pyrolysis process. This temperature drop is caused when ash is melted in a combustion furnace and is slagged to be taken out (generally about 1200 ° C or higher, preferably 13 ° C or higher).
It is a very disadvantageous factor for (requires about 00 ° 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 direct heating system which does not directly introduce the flue gas into the thermal decomposition reactor, it is possible to avoid the harmful effects of directly introducing the flue gas into the thermal decomposition reactor. it can. 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.

Further, there is a super refuse power generation technology as a technology for increasing the efficiency of power generation by waste. This technology aims to utilize the unused energy by using another heat engine to raise the temperature of the steam generated from the refuse incineration facility to perform highly efficient steam turbine power generation. (1) Combined system with a fuel-fired boiler, (2) Fuel-fired superheater addition system,
(3) There is a combined system with a gas turbine.

Of these, FIG. 4 is a system diagram of a conventional super refuse power generation facility using a combined system with a gas turbine. In this technique, air is compressed by a compressor, mixed with fuel in a combustor 101, and burned, and the combustion exhaust gas is sent to a gas turbine 102 to perform normal power generation by a generator 103. With the exhaust gas, the low temperature steam from the incinerator boiler 107 of the refuse incinerator is heated to a high temperature by the superheater 104 and sent to the steam turbine 105, and the power generation by the generator 106 is performed more efficiently than the normal waste power generation. . 109 is a condenser and 108 is a pump.

[0014]

However, in the above-mentioned super refuse power generation technology, the temperature of the exhaust gas supplied from the gas turbine is about 500 ° C., and the exhaust gas is used to generate the steam obtained by burning the waste. Even if power is generated using a steam turbine with superheating, the power generation efficiency on the steam turbine side is at most about 20 to 25% on the basis of the lower heating value of the total waste and turbine fuel, which is not sufficiently high. .

The above-mentioned West German Patent Publication No. 37
25704.8, West German Patent Publication No. 381182
0.3, the waste treatment technology disclosed in Japanese Patent Laid-Open No. 1-49816 uses only the power generation by the steam turbine, so the power generation efficiency cannot be said to be sufficiently high. Generally, for example, the power generation efficiency is about 10 to 15% in an incinerator power generation facility with a boiler for municipal waste.

The present invention relates to a waste treatment technology for thermally decomposing waste, converting the thermal energy generated by burning the thermally decomposed product into electric power, and recovering it. It is an object of the present invention to provide a waste treatment device and method having a higher power generation efficiency than the conventional super refuse power generation technology by using a direct heating system that burns a part to self-supply heat of thermal decomposition.

[0017]

A first aspect of the invention for solving the above-mentioned problems is to heat and pyrolyze a waste material to separate it into a low temperature carbonization gas and a pyrolysis residue mainly consisting of non-volatile components. A pyrolysis reactor, a first combustor for combusting the char separated from the pyrolysis residue and the low-temperature carbonization gas, and a waste heat boiler for generating steam by the heat of combustion exhaust gas from the combustor, In a waste treatment device including a steam power generator driven by steam generated in a waste heat boiler, a second combustor for driving a turbine for power generation and one of the low-temperature carbonization gas after the separation A low-temperature carbonization gas introduction path for extracting a part from the pyrolysis reactor, and a third low-temperature carbonization gas for extracting the extracted low-temperature carbonization gas as combustion air using the combustion exhaust gas after being driven by the turbine discharged from the second combustor. The combustor and A first combustion exhaust gas introducing passage for directly introducing combustion exhaust gas generated by combustion by a third combustor into the thermal decomposition reactor to serve as the heating source of the thermal decomposition reactor; Waste treatment equipment.

Further, a second combustion exhaust gas introducing passage for introducing a part of the combustion exhaust gas after driving the turbine to the first combustor and making it as combustion air of the combustor is provided. The waste treatment apparatus of the first invention is defined as the second invention.

According to the first invention, an air preheater for preheating the combustion air introduced into the first combustor is provided with a part of the combustion exhaust gas after driving the turbine as a heat source. A waste treatment device is a third invention.

The step of heating and thermally decomposing the waste to separate it into a low temperature carbonization gas and a thermal decomposition residue mainly consisting of non-volatile components, and the char separated from the thermal decomposition residue and the low temperature carbonization gas. In a waste treatment method including a step of combusting, a step of generating steam by heat of combustion exhaust gas generated in this combustion step, and a step of generating power with this generated steam, a turbine is driven by combustion exhaust gas from a combustor And a step of taking out a portion of the separated low-temperature carbonization gas from the pyrolysis reactor, and the extracted low-temperature carbonization gas is burned with the combustion exhaust gas after driving the turbine as combustion air. And a step of directly introducing the combustion exhaust gas generated by this combustion into the thermal decomposition reactor to be the heating source of the thermal decomposition reactor. Things processing method and the fourth aspect of the present invention.

A fifth aspect of the waste treatment method of the fourth invention is characterized in that the step of burning the char and the low-temperature carbonized gas is performed by using a part of the combustion exhaust gas after driving the turbine as combustion air. Invention.

A waste of the fourth invention, characterized by including a step of preheating combustion air for burning the char and the low temperature carbonization gas by using a part of the combustion exhaust gas after driving the turbine as a heat source. A material processing method is defined as a sixth invention.

[0023]

According to the above inventions, the combustion exhaust gas after driving the turbine to generate electricity is used as combustion air to burn a part of the low-temperature carbonization gas produced by thermal decomposition, and the combustion exhaust gas is subjected to a thermal decomposition reaction. Directly introduced into the reactor and used as a heat source for the pyrolysis reactor, or as combustion air for combustion of char and low-temperature carbonization gas, or preheating of combustion air for combustion of char and low-temperature carbonization gas. Indirect heat source. Therefore, the combustion exhaust gas after driving the turbine to generate power finally becomes high-temperature combustion exhaust gas due to the combustion of the char and the low-temperature carbonization gas, and directly serves as a heat source for steam generation for driving the steam generator. Therefore, the temperature of the combustion exhaust gas as it is after driving the turbine to generate power (for example,
At about 500 ° C.), the exhaust gas can be used to generate power with higher efficiency than steam generated by burning waste is superheated in a superheater to generate electric power using a steam generator.

According to the first and fourth aspects of the invention, the combustion exhaust gas after driving the turbine to generate power is consumed as combustion air for burning a part of the low-temperature carbonization gas produced by thermal decomposition,
This can be the direct heat source for the pyrolysis reactor.
Therefore, this case is suitable when it is desired to set the thermal decomposition temperature to a high temperature.

According to the second, third, fifth and sixth inventions, in addition to the first and fourth effects, the combustion exhaust gas after driving the turbine to generate electricity is set as follows. It is used for combustion in the combustor. In the second and fifth inventions, the first and fourth aspects
In addition to the effect of the above, the combustion exhaust gas after driving the turbine to generate power is used as combustion air for burning the char and the low-temperature carbonization gas, and the char separated from the pyrolysis residue and the low-temperature carbonization gas are combusted. In the third and sixth inventions, in addition to the first and fourth effects, the combustion exhaust gas after driving the turbine to generate electricity is used as the heat source for preheating the char and the combustion air of the low-temperature carbonization gas. The above second and fifth inventions, or
In the third and sixth aspects of the invention, the ratio between the amount of waste treated and the amount of flue gas after driving the turbine and generating electricity required for the treatment is determined by each method. In the general combination of turbine power generation and waste treatment system, power is generated when the ratio of the amount of waste gas and combustion exhaust gas to the amount of combustion exhaust gas after driving the turbine to generate power is relatively large. Efficiency is low, and power generation efficiency tends to be high if a system with a relatively small ratio is adopted.

According to the second and fifth aspects of the present invention, when the char and the low temperature carbonization gas are burned, the amount of the exhaust gas after driving the turbine to generate the combustion exhaust gas is small because the O ₂ content is small. The amount of heat exchange in the waste heat boiler is large, and the amount of steam generated is large because the amount is large compared to the case of supplying. In this case, the power generation efficiency is higher than in the cases of the third and sixth inventions, but the amount of waste treated is small. The present invention is suitable when power generation efficiency is prioritized.

According to the third and sixth inventions, as compared with the second and fifth inventions, the combustion temperature of the char and the low-temperature carbonization gas can be increased, so that the ash is melted by the combustion of the char and the low-temperature carbonization gas. When solidification is desired (generally about 1200 ° C. or higher is required), the present invention is preferable. In the present invention,
The amount of waste can be increased compared to the second and fifth inventions,
The power generation efficiency becomes small. Therefore, the present invention is suitable when priority is given to the amount of waste. In each invention, the use of combustion exhaust gas can be applied not only to a gas turbine but also to an internal combustion engine such as a diesel engine.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall system diagram of a waste treatment device according to a first embodiment of the present invention. Reference numeral 1 is a waste supply device for supplying waste to a thermal decomposition reactor 2 as an example of a thermal decomposition reactor in the present invention. 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. A suitable example is also shown in Japanese Patent Laid-Open No. 3-63407.

FIG. 2 is a system diagram showing an example of a main part of the first embodiment of the present invention. The thermal decomposition reactor 2 is rotated as shown by an arrow 15, and the waste 100 is heated to about 300 to 900 ° C., and about 300 to 600 ° C. for taking out unmelted aluminum and the like from the thermal decomposition residue as valuables. Then, it is pyrolyzed to form a low temperature dry distillation 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 pyrolysis residue separating device 51. The low-temperature carbonization gas is supplied from the low-temperature carbonization gas discharge pipe 4 provided on the upper side of the carry-out device 3, and partly through the blower 8,
First as an example of the low-temperature carbonization gas introduction passage in the present invention
Is introduced into the burner 9 of the combustion furnace 11 as an example of the third combustor of the present invention by the low-temperature carbonization gas branch pipe 7 of the present invention, and the rest is the low-temperature carbonization gas conduit 6 as an example of the first combustor of the present invention To the burner 50 of the combustor 55.
The burner 9 is a burner provided in the combustor 11.

Reference numeral 35 denotes a combustor as an example of the second combustor in the present invention. Compressed air from the air compressor 27 is supplied by an air supply pipe 28 to combust liquid fuel or the like, and its combustion exhaust gas is used. The gas turbine 29 is driven and the generator 30 generates electric power. A part of the combustion exhaust gas after being used for power generation in the gas turbine 29 is guided to the burner 9 as combustion air by the exhaust gas supply pipe 32, and the remaining part is a part of the second combustion exhaust gas introduction passage in the present invention. The exhaust gas supply pipe 31 as an example guides the burner 50 as combustion air. The exhaust gas supply pipes 32 and 31 are provided with flow rate adjusting valves 34 and 33 for adjusting the combustion exhaust gas flow rate, respectively.

From the first low-temperature carbonization gas branch pipe 7, the second
The low temperature carbonization gas branch pipe 21 is branched. 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. The first and second low temperature carbonization gas branch pipes 7 and 21 are provided with blowers 22 and 2 respectively.
3 is provided, and further downstream of the blowers 22 and 23, control valves 24 and 25 for adjusting the amount of combustion exhaust gas are provided.
Are provided respectively. Reference numeral 16 denotes a combustion exhaust gas supply pipe as an example of the first combustion exhaust gas introduction passage in the present invention, which connects the combustor 11 and the thermal decomposition reactor 2.
The combustion exhaust gas from the combustor 11 is supplied to the combustion exhaust gas supply pipe 16
Is directly introduced into the thermal decomposition reactor 2 to heat the waste 100, and serves as a heating source for thermal decomposition of the thermal decomposition reactor 2.

In the combustion exhaust gas supply pipe 16, this pipe 16
An oxygen concentration meter 17 for detecting the oxygen concentration in the combustion exhaust gas flowing inside is provided. The detection signal of the oxygen concentration by 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 controls the regulating valve 24 to control the first valve.
The amount of low temperature carbonization gas flowing through the low temperature carbonization gas branch pipe 7 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 there, and the second low-temperature carbonization gas branch pipe 21 A certain amount of other low temperature carbonization gas is supplied to consume the residual oxygen in the combustion exhaust gas flowing downstream of the flame of the burner 9 and remain in the combustion exhaust gas introduced into the thermal decomposition reactor 2. Suppress the amount of oxygen. It is desirable to suppress the residual oxygen amount so that the combustion exhaust gas is in a substantially oxygen-free state. Therefore, the exhaust gas supply pipe 3
The amount of combustion exhaust gas supplied via 2 exceeds the amount of oxygen capable of stoichiometrically completely combusting the low-temperature carbonization gas supplied by the first low-temperature carbonization gas branch pipe 7 or is stable without extinguishing the fire. Control valve 2 so that the amount of oxygen continues to burn
4, the amount of the low temperature carbonization gas supplied via the second low temperature carbonization gas branch pipe 21 is equal to or more than the amount that can completely consume the residual oxygen in the combustion exhaust gas generated in the combustor 11. Therefore, it is desirable to control the control valve 25.

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. In addition, 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, 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 on the conveyor line 5.
2 is introduced into the burner 50. Combustion exhaust gas of the internal combustion engine 29 is introduced into the burner 50 from the exhaust gas supply pipe 31 as combustion air. The burner 50 is the burner of the combustor 55. In the combustor 55, the low temperature carbonization gas and char are burned with this combustion air. In this case, the ash is melted by burning at high temperature under an excess oxygen condition (the temperature is about 1200 ° C. or higher, preferably about 1300 ° C.), and is dropped into the cooling water tank 56 from the bottom of the combustor 55 to be rapidly cooled and taken out as slag. It can also be configured.

Reference numeral 57 denotes a waste heat boiler as an example of the waste heat boiler of the present invention, which obtains high temperature steam by heat exchange with the combustion exhaust gas guided by the conduit 58. This high temperature steam is guided to a conduit 60 and used for power generation or the like in a steam generator 59 as an example of the steam generator of the present invention. The combustion exhaust gas after the heat exchange in the waste 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.). Then, it is guided to the conduit 65 and discharged from the chimney 66. It is desirable that the ash removed by the dust collector 62 be returned to the combustor 55 in the transfer line 68. 67 is an exhaust gas compressor. Excess exhaust gas from the gas turbine 29 other than the amount supplied to the combustor 11 and the combustor 55 is guided to the conduit 58 by the pipe 69 and mixed with the combustion exhaust gas from the combustor 55 to generate a waste heat boiler. Introduce to 57.

Next, the operation of this embodiment will be described. According to the above-described present embodiment, the gas turbine 29 is driven to use the combustion exhaust gas after power generation as combustion air to burn a part of the low-temperature carbonization gas generated by thermal decomposition, and the combustion exhaust gas is used as a thermal decomposition reactor. 2 directly into the pyrolysis reactor 2
Or as combustion air in the combustion of char and low temperature carbonization gas in the combustor 55. Therefore, the combustion exhaust gas after driving the gas turbine 29 to generate power finally becomes a high-temperature combustion exhaust gas due to the combustion of char and the low-temperature carbonization gas, and becomes a heat source for generating steam for driving the steam generator 59 as it is. . Therefore, using this exhaust gas at the same temperature (for example, about 500 ° C.) of the combustion exhaust gas after driving the gas turbine 29 to generate power,
High-efficiency power generation can be performed as compared with the case where steam produced by burning waste is superheated by a superheater to generate electric power using a steam generator.

In the present embodiment, the combustion exhaust gas after driving the gas turbine 29 to generate electric power is used as combustion air in the combustion of the char and the low-temperature carbonization gas, and the char separated from the pyrolysis residue and the low-temperature carbonization gas are used. It burns and.

The amount of combustion exhaust gas after driving the gas turbine 29 to generate power for combustion of char and low-temperature carbonization gas is large compared to the case of supplying air because the O ₂ content is small. Therefore, the amount of heat exchange in the waste heat boiler 57 increases, and the amount of steam generated increases. In this case, the power generation efficiency is higher than in the case of the second embodiment described below in which the combustion air is preheated by using a part of the combustion exhaust gas after driving the gas turbine 29 to generate power as a heat source, The amount of waste will be reduced. When giving priority to power generation efficiency, it is preferable to use the first embodiment.

The following will show each data of the waste treatment experiment conducted by the inventors of the present invention during the bench test grade steady operation using the waste treatment apparatus having the above-mentioned configuration.

1. Input waste: General waste roughly crushed to a particle size of about 50 mm or less (water content: 25.6%, paper / contains / fiber / vegetation: subtotal 62.1%, plastic / rubber / leather:
Subtotal 5.9%, Iron: 1.1%, Non-ferrous metal: 0.6%, Glass: 1.7%, Stone / Pottery: 0.3%, Others: 2.7%,
Lower heating value 2990 kcal / kg) Input amount 3.9 kg / hr.

2. Exhaust gas from gas turbine 29: O ₂
Content rate 14.3 vol%, temperature 500 ° C., supply amount to combustor 11 2.61 Nm ³ / hr, inlet temperature 500 ° C., combustor 55
Supply amount to the tank is 20.46 Nm ³ / hr, inlet temperature is 500 ° C.

3. Conditions at the outlet of the pyrolysis reactor 2 for low temperature carbonization gas: gas flow rate of 10.99 Nm ³ / hr, outlet temperature of about 4
50 ° C., branching ratio (flow rate of branching gas to low-temperature carbonization gas branch pipe 7 / gas flow rate at outlet of pyrolysis reactor 2) 0.112, circulation ratio (pyrolysis reactor 2 to low-temperature carbonization gas branch pipe 7, combustion Flow rate of low-temperature carbonization gas circulating through the reactor 11 to the thermal decomposition reactor 2 / flow rate of low-temperature carbonization gas at the outlet of the thermal decomposition reactor 2)
358.

4. Combustor 11: combustion exhaust gas temperature on the outlet side is about 1000 ° C., combustion exhaust gas flow rate is 7.72 Nm ³ / hr.

5. Pyrolysis residue: The amount of pyrolysis residue carried out from the lower part of the carry-out device 3 was 0.83 kg / hr, of which the classification device 51 classifies and then finely grinds particles having a particle size of 5 mm or less to a particle size of about 50 μm. (This weight is 0.66 kg / hr), and loaded into the combustor 55. The unoxidized residue having a particle size of 5 mm or more was directly recovered (0.17 kg / hr).

6. Combustor 55: Maximum temperature reached in the furnace is about 13
It was possible to perform combustion while separating and carrying in flue ash dust at 60 ° C. with the filtration device 62, and to collect the slag by water cooling and solidifying it in the cooling water tank 56 (0.18 kg / hr).

Based on the above experimental data, a commercially available gas turbine was used as the gas turbine 29 (the power generation efficiency of the gas turbine alone was 26%), and the scale was such that it could be put to practical use (combustion exhaust gas amount: 79300 Nm ³ / hr, treatment disposal). Input amount:
When the power generation efficiency was calculated by scaling up to 13.3 t / hr), the waste treatment amount was 320 t / d, gas turbine 2
It was calculated that the output of 9 was 5540 kW, the output of the steam turbine in the steam generator 59 was 12300 kW, and the total power generation efficiency was 26.4%. In addition, in the above-mentioned experimental data at the time of steady operation of the bench test class, the heat loss available in the exhaust heat boiler 57, that is, the heat loss from the pyrolysis reactor 2 to the combustor 55, the heat loss is 13.7%. Was estimated. Since the heat loss can be reduced by scaling up, it is clear that the power generation efficiency can be further improved in a device that can be put to practical use. When calculating the power generation efficiency under the ideal condition that the heat loss was 0%, it was about 29%. Therefore, according to the waste treatment apparatus of the present embodiment, it is possible to provide a waste treatment technique having higher power generation efficiency than the conventional super refuse power generation.

Next, a second embodiment of the present invention will be described. FIG. 3 is an overall system diagram of a waste treatment device according to a second embodiment of the present invention. Members designated by the same reference numerals as those in FIGS. 1 and 2 are the same members as those in the first embodiment described with reference to FIGS. 1 and 2, and detailed description thereof will be omitted.

The difference of this embodiment from the first embodiment is that
In place of the exhaust gas supply pipe 31, an exhaust gas supply pipe 39 for guiding a part of the combustion exhaust gas from the internal combustion engine 29 to the conduit 61 is provided,
An air preheater 38 is provided on the exhaust gas supply pipe 39, an air supply pipe 36 is connected to the burner 50, and combustion air supplied to the burner 50 by the air compressor 37 is used as a heat source for the combustion exhaust gas from the internal combustion engine 29. There is a point to preheat.

Next, the operation of this embodiment will be described. According to this embodiment, the combustion temperature of the char and the low-temperature carbonization gas can be increased as compared with the first embodiment, so that when it is desired to melt and solidify the ash by burning the char and the low-temperature carbonization gas (generally 1200 ° C.). It is desirable to use this embodiment for the above requirement. In this embodiment, as compared with the above-mentioned first embodiment, the amount of waste treated can be increased, but the power generation efficiency is reduced. Therefore, when it is desired to give priority to the amount of waste processing, the second embodiment is suitable.

Also in the present example, each data of the waste treatment experiment at the time of steady operation of bench test class using the waste treatment apparatus of the above-mentioned construction conducted by the present inventors will be shown.

1. Input waste: General waste roughly crushed to a particle size of 50 mm or less (water content 25.6%, paper / contains / fiber / vegetation: subtotal 62.1%, plastic / rubber / leather: subtotal 5.9%, Iron: 1.1%, non-ferrous metal: 0.6%, glass: 1.7%, stone / pottery: 0.3%, other: 2.7%,
Lower heating value 2990 kcal / kg) Input amount 3.9 kg / hr.

2. Exhaust gas from gas turbine 29: O ₂
Content rate 14.3 vol%, temperature 500 ° C., supply amount to combustor 11 2.61 Nm ³ / hr, inlet temperature 500 ° C., exhaust gas amount for air preheater 38 7.16 Nm ³ / hr, inlet temperature 500
° C.

3. Conditions at the outlet of the pyrolysis reactor 2 for low temperature carbonization gas: gas flow rate of 10.99 Nm ³ / hr, outlet temperature of about 4
50 ° C, branching ratio 0.112, circulation ratio 0.358.

4. Combustor 11: combustion exhaust gas temperature on the outlet side is about 1000 ° C., combustion exhaust gas flow rate is 7.72 Nm ³ / hr.

5. Pyrolysis residue: The amount of pyrolysis residue carried out from the lower part of the carry-out device 3 was 0.83 kg / hr, of which the classification device 51 classifies and then finely grinds particles having a particle size of 5 mm or less to a particle size of about 50 μm. Brought into the combustor 55. The unoxidized residue (0.17 kg / hr) having a particle size of 5 mm or more was directly recovered.

6. Combustor 55: Maximum temperature reached in the furnace is about 14
It was possible to carry out combustion while separating and carrying in flue ash dust at 50 ° C. with the filtration device 62, and to collect the slag by cooling it with water in the cooling water tank 56 (0.18 kg / hr).

Based on such data, the scale up as in the first embodiment is carried out, and the same gas turbine as in the case of the first embodiment is used, and the scale can be put to practical use (combustion exhaust gas amount 79300 Nm ³ / hr, Input amount of processing waste 21.6t /
hr), the total power generation efficiency was calculated to be 22.7
It became%. The heat loss of this example was estimated to be 10.8%. Also in this embodiment, when the power generation efficiency under the condition that the heat loss is 0% is calculated, the waste treatment amount is 520 t / d, the output of the gas turbine 29 is 5540 kW, the output of the steam turbine in the steam generator 59 is 16350 kW, and the total power generation efficiency is 25.
% Was calculated. As described above, according to the present embodiment, it is possible to realize power generation efficiency that is not inferior to the conventional super refuse power generation even if priority is given to increasing the amount of waste disposal.

Further, in any of the above-mentioned embodiments, the oxygen concentration in the combustion exhaust gas of the combustor 11 is detected by the oxygen concentration meter 17 before being introduced into the pyrolysis reactor 2, so that a portion of the low-temperature carbonization gas is obtained. The amount of combustion exhaust gas from the exhaust gas supply pipe 32 is adjusted by the controller 26 by the controller 26 so that it can be burned with more oxygen than stoichiometrically completely burned, or in order to continue burning stably without extinguishing the fire. The residual oxygen in the combustion exhaust gas from the reactor 11 can be consumed and suppressed by adding the low-temperature carbonization gas from the second low-temperature carbonization gas branch pipe 21, so that the thermal decomposition of the waste is favored. In addition, it is possible to realize thermal decomposition of the direct heating system 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 cause explosion.

That is, although the thermal decomposition can be satisfactorily performed in a reducing atmosphere in which oxygen does not exist,
The aforementioned European Patent Publication No. The direct heating method disclosed in 0360052A1 tends to supply an excessive amount of air in order to stably maintain the partial combustion of the low-temperature carbonization gas. 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.

According to each of the above-mentioned embodiments, such a situation can be prevented, and a situation in which the flame disappears unexpectedly, which tends to occur during incomplete combustion, can be suppressed, and stable combustion can be achieved. Can be maintained. 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.

In the above embodiment, the gas turbine 29 is used.
The combustion exhaust gas of the combustor 35 for driving the combustor 11
However, it is also possible to use an internal combustion engine such as a diesel engine and introduce the combustion exhaust gas from this internal combustion engine.

[0063]

EFFECTS OF THE INVENTION According to the present invention described above, the waste treatment technology for thermally decomposing waste and converting the thermal energy generated by burning the thermal decomposition product into electric power for recovery is described. It is possible to provide a waste treatment device and method having higher power generation efficiency than the conventional super refuse power generation technology by using a direct heating method in which a part of the generated low-temperature carbonization gas is burned to supply heat of pyrolysis by itself.

[Brief description of drawings]

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

FIG. 2 is a system diagram of a main part of the waste treatment apparatus according to the first embodiment of the present invention.

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

FIG. 4 is a system diagram of a conventional super refuse power generation facility using a combined system with a gas turbine.

[Explanation of symbols]

 2 Pyrolysis reactor 7 First low temperature carbonization gas branch pipe 11, 35 Combustor 16 Combustion exhaust gas supply pipe 29 Gas turbine 30 Generator 31, 32 Exhaust gas supply pipe 38 Air preheater 55 Combustor 57 Waste heat boiler 59 Steam power generation Machine

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tsuyoshi Suzuki 5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui Engineering & Shipbuilding Co., Ltd.

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. A first combustor that combusts a low-temperature carbonization gas, a waste heat boiler that generates steam by the heat of combustion exhaust gas from the combustor, and a steam generator driven by the steam generated by the waste heat boiler are provided. In the waste treatment device, a second combustor for driving a turbine for power generation, a low-temperature carbonization gas introduction path for extracting a part of the low-temperature carbonization gas after the separation from the pyrolysis reactor, A third combustor that burns the extracted low-temperature carbonization gas as combustion air after the turbine is driven, which is discharged from the second combustor, and combustion exhaust gas that is generated by the combustion by the third combustor. The above Directly introduced into the decomposition reactor, waste treatment apparatus characterized by and a first flue gas introduction passage to the heat source of the thermal decomposition reactor. 2. A second combustion exhaust gas introduction passage for introducing a part of the combustion exhaust gas after driving the turbine to the first combustor and using it as combustion air for the combustor. The waste treatment device according to claim 1. 3. An air preheater for preheating the combustion air to be introduced into the first combustor by using a part of the combustion exhaust gas after driving the turbine as a heat source. The waste treatment device according to the item. 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, which includes a step of combusting an exhaust gas, a step of generating steam by heat of the combustion exhaust gas generated in the combustion step, and a step of generating power by the generated steam, To generate power by driving the turbine, a step of extracting a part of the separated low-temperature carbonization gas from the pyrolysis reactor, and the extracted low-temperature carbonization gas is used as combustion air for combustion exhaust gas after driving the turbine. And a step of directly introducing the combustion exhaust gas generated by this combustion into the thermal decomposition reactor to be the heating source of the thermal decomposition reactor. Wastes processing method. 5. The waste treatment method according to claim 4, wherein the step of burning the char and the low-temperature carbonized gas is performed by using a part of the combustion exhaust gas after driving the turbine as combustion air. . 6. The method according to claim 4, further comprising the step of preheating combustion air for combusting the char and the low-temperature carbonization gas by using a part of the combustion exhaust gas after driving the turbine as a heat source. Waste treatment method described.