JPH09329311A - Thermal decomposition system of waste in waste processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To construct an apparatus compactly and inexpensively by supplying an insufficient heat amount with the aid of an additional burning apparatus by employing a thermal decomposition reactor capable of a thermal decomposition reaction by being supplied with a minimum. heat amount by taking the properties of a waste into consideration SOLUTION: The present waste processing apparatus comprises a thermal decomposition reactor 2, a combustor 6 for combusting dry distillation gas and combustible components exhausted from the thermal decomposition reactor 2, an air heater 7 for heating heating air with combustion gas produced from the combustor 6, and a heating air line for supplying the heating air from the air heater 7 to the thermal decomposition reactor 2. A thermal decomposition system of the waste sets heating temperature of the heating air to minimum temperature required for thermal decomposition of a waste (a) introduced into the thermal decomposition reactor 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for thermally decomposing waste in an apparatus for treating waste, more specifically, the waste is heated under a pressure of atmospheric pressure or less to be thermally decomposed to produce a dry distillation gas and a residue of thermal decomposition. The present invention relates to a thermal decomposition method in a waste treatment device in which a dry distillation gas and a combustible component separated from a thermal decomposition residue are supplied to a combustor for combustion treatment.

[0002]

2. Description of the Related Art As one of the industrial waste treatment devices containing general waste such as municipal solid waste and combustibles such as waste plastic, the waste is put into a thermal decomposition reactor in a low oxygen atmosphere below atmospheric pressure. It is heated and pyrolyzed to produce a dry distillation gas and a pyrolysis residue mainly composed of non-volatile components, and after further cooling the pyrolysis residue, it is supplied to a separation device to produce a combustible component mainly containing carbon. , For example, it is separated into non-combustible components made of rubble such as metal, pottery, gravel, concrete pieces, etc., combustible components are pulverized, and the combustible components pulverized and the above-mentioned carbonization gas are melted in the combustor. Introduced into the furnace, burned in this melting furnace, the resulting combustion ash and ash contained in the combustible components as molten slag, discharge this molten slag to solidify by cooling, and combustion generated in the melting furnace Add heated air with gas And, the heated air is supplied to the pyrolysis reactor waste waste so as to process the processing apparatus is proposed in JP-Sho 64-49816.

[0003]

By the way, in such a waste treatment apparatus, a method of heating heated air for thermally decomposing waste by using combustion gas discharged from the melting furnace is adopted. Cause problems. That is, in order to thermally decompose the waste supplied in the thermal decomposition reactor,
A certain amount of heat is required, but the properties of waste change variously. For example, when taking city waste as an example, there are waste with a large amount of water and waste with a small amount of water, and thus the predetermined amount of heat changes.

On the other hand, since the temperature of the combustion gas is almost constant because it is necessary to melt the combustion ash and the like, heating air is usually supplied so that the maximum heat quantity can be supplied to the thermal decomposition reactor within the expected heat quantity range. The temperature and the area of the heat transfer surface of the pyrolysis reactor are defined. However, in the temperature of the heated air and the area of the heat transfer surface of the thermal decomposition reactor set in this way, for example, when the amount of heat required for thermal decomposition is small and the amount of moisture is small, Of heat, that is, the temperature is excessively increased, and the heat transfer area is also excessively increased. As a result, not only the thermal efficiency is deteriorated, but also a device such as a heat exchanger or a thermal decomposition reactor. Will be larger, and the cost will increase. In addition, since heat is exchanged with the high-temperature combustion gas, the air heater needs to have corrosion resistance and heat resistance, and there is a problem that the cost of the entire apparatus becomes high.

[0005]

The present invention has been made in order to solve the above-mentioned problems of the prior art, in which waste is thrown in and the inside pressure is maintained below atmospheric pressure. Pyrolysis reactor, combustor for combusting dry distillation gas and combustible components discharged from the pyrolysis reactor, heater for heating a heating medium by combustion gas generated by the combustor, and heating In a waste treatment device comprising a heating medium line for supplying the heating medium of the reactor to the thermal decomposition reactor, the heating temperature of the heating medium is set to a value required for the thermal decomposition of the waste introduced into the thermal decomposition reactor. The present invention provides a waste thermal decomposition method in a waste treatment device, which is characterized in that the temperature is set to the minimum temperature.

That is, the temperature is set to supply the minimum amount of heat within the range in which the amount of heat required for thermal decomposition (steaming) varies, taking into consideration changes in the properties of waste. Then, on the downstream side of the air heater, a reheating device including an electric heater or a burner that uses fuel oil such as kerosene or light oil is arranged,
This reheating device is controlled by directly detecting the property of the waste supplied to the thermal decomposition reactor or by detecting the property of the thermal decomposition residue after the thermal decomposition reaction.

According to the thermal decomposition method of the waste in the waste treatment apparatus constructed as described above, the heating medium has a minimum temperature required for the thermal decomposition of the waste introduced into the thermal decomposition reactor. Is heated by a heater. Since the temperature required for this thermal decomposition changes as the property of the waste changes, the reheating device is controlled to change the temperature of the heating medium when it becomes necessary to change the temperature of the heating medium. Of.

The property of the waste is changed directly at the time of charging or by detecting unreacted components in the thermal decomposition residue. As a result, not only the pyrolysis reactor can be downsized, but also the temperature of the combustion gas that exchanges heat with the heater can be lowered.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a waste thermal decomposition method in a waste treatment apparatus according to the present invention will be described with reference to the drawings. 1 is a waste supply device for inputting waste a,
The waste supply device 1 includes a crane 4 having a bucket 3.
And a screw feeder 5.

The pyrolysis reactor 2 is composed of a horizontal rotary drum, and heats air b (heat medium) heated by an air heater 7 arranged downstream of the melting furnace 6 which is a combustor.
Directly via the heating air line L _1, or heating switching valve 8a provided in the air line L _1, by operating the 8b, via a bypass line L ₂ having a electric heater 9 as follow fired device heat It is adapted to be supplied to the decomposition reactor 2.

That is, for one pyrolysis reactor 2,
An air heater 7 and an electric heater 9 as a reheating device are provided together, and in normal operation, the heated air b heated by the air heater 7 is used as a heat source of the thermal decomposition reactor 2 and waste a When the amount of heat given by the air heater 7 is insufficient due to the nature and the amount of supply, the reheating device is operated as an auxiliary heating device to supply the required amount of heat.

In the above apparatus, waste a crushed by a crusher (not shown) to a predetermined size of, for example, 150 mm or less is used by the waste supply device 1 to pyrolyze the reactor 2
Is heated inside and thermally decomposed by the heated air b supplied into the heat transfer tube arranged along the wall surface of the pyrolysis reactor 2 and is composed of the carbonization gas G ₁ and mainly non-volatile components. Pyrolysis residue c is produced.

As described above, the property of the waste a changes variously. Specifically, the properties of the thermal decomposition reactor 2 change depending on the temperature conditions and the water content changes with the changes of the four seasons, and therefore the amount of heat required for thermal decomposition in the thermal decomposition reactor 2 also changes. Therefore, the temperature and flow rate of the heated air (heating medium) after heating and the heat transfer area of the air heater 7 or the thermal decomposition reactor 2 are set so that the minimum required amount of heat within the expected amount of heat can be supplied in advance. Is determined and the heated air b heated by the air heater 7 so as to reach the temperature is supplied to the pyrolysis reactor 2 from the heated air line L ₁ .

Of course, the setting of the temperature at which the minimum required amount of heat is expected may be set by selecting the waste a having a large amount to be processed, which is in the property of the waste a to be processed. Good. Then, first, the property of the waste a is detected by the detector 10 provided at the input port of the screw feeder 5, and the signal V ₁ is input to the control device 11. The control device 11 is composed of a storage device 12, a comparator 13, a calculation device 14 and a signal generation device 15. When the signal V _{1 of the} detector 10 is input to the calculation device 14 of the control device 11, this is discarded. The amount of heat required for the thermal decomposition of the object a is obtained, and its signal V
₂ is input to the comparator 13, where a signal V _{3 of a} predetermined heat quantity (minimum necessary heat quantity), which is previously input to the storage device 12, is input.
If the amount of heat required for pyrolysis is “negative”, the signal V ₄ is input to the signal generating device 15 and the control signal V ₄ is input.
₅ is created.

The control valve V ₅ controls the switching valve 8
By switching a and 8b and operating the electric heater 9, the heated air b is heated and heated through the bypass line L ₂ .
The waste a supplied and supplied to the thermal decomposition reactor 2 is heated and thermally decomposed. An electric heater 9 as a reheating device
Is not limited to this, and, for example, a kerosene-fired burner can also be used.

In this way, when the waste a is pyrolyzed, the dry distillation gas G ₁ and the pyrolysis residue c mainly composed of the non-volatile components are produced, and both are separated by the discharge device 16, and the dry distillation gas G ₁ is produced. It is led to the burner 17 of the melting furnace 6 from the cracked gas line L ₃ . On the other hand, the thermal decomposition residue c is cooled by the cooling device 18.
After being cooled to a temperature at which there is no risk of ignition, for example, to about 80 ° C., it is separated into a combustible component d such as carbon and a non-combustible component e such as metal or rubble by a separating device 19, and the non-combustible component e Is collected in the container 20, and the combustible component d is pulverized by the pulverizer 21 into fine powder of 1 mm or less, for example.

Then, the combustible component d'which has been crushed is used.
Is the burner 17 of the melting furnace 6 from the carbon supply line L _4.
Of about 1,300 in the melting furnace 6 by the dry distillation gas G ₁ supplied from the decomposition gas line L ₃ and the combustion air f supplied from the combustion air line L ₅ by the forced draft fan 22. It is burnt in the high temperature range of ℃. Then, the combustion ash generated by this combustion process becomes molten slag g and flows down, and is cooled and solidified in the water tank 23. The solidified slag can be effectively used for various uses of building materials such as paving materials.

On the other hand, the combustion gas G ₂ generated in the melting furnace 6
Is recovered by the air heater 7 and the waste heat boiler 24 through the combustion gas line L ₆ , further dust-removed by the dust collector 25, and washed and desulfurized by the cleaning device 26 to obtain a relatively low temperature clean exhaust gas G. ₃ and mostly chimney 27
More released to the atmosphere. A part of the gas is supplied to the cooling device 18 through the inert gas line L ₇ . In addition, 28 is steam s generated by the waste heat boiler 24
Is a power generation device for generating electric power by using 29, and 29 is an induction blower for keeping the pressure in the cleaning device 26 from the thermal decomposition reactor 2 at atmospheric pressure or lower to prevent gas leakage.

FIG. 2 shows another embodiment, in which the property of the pyrolysis residue c separated by the discharge device 16 and cooled by the cooling device 18 is detected by the detector 30, and its signal V ₆ is detected.
Is input to the control device 11.
That is, when the temperature of the heating air b supplied from the predetermined heating air line L ₁ is low and the amount of heat is insufficient, the thermal decomposition of the waste a supplied into the thermal decomposition reactor 2 is not sufficiently performed. Means that unreacted combustible components are present in the thermal decomposition residue c. Therefore, the unreacted combustible component is detected by the detector 30, and the signal V ₆ thereof is input to the control device 11, and the control signal V ₅ is created in the same manner as in the above-mentioned embodiment to select the switching valves 8a and 8b and the electric heater. 9 is controlled. In the present invention, the heated air heated in the latter stage is used as the heat source of the thermal decomposition reactor 2, but it is also possible to use superheated steam depending on the configuration of the apparatus.

[0020]

As is apparent from the above description, according to the thermal decomposition method of waste in the waste treatment apparatus of the present invention, the heating medium supplied to the thermal decomposition reactor is required for thermal decomposition of the waste. When the amount of heat changes, the temperature was set beforehand to the minimum temperature required for thermal decomposition, and when the amount of heat was insufficient due to changes in the properties of the waste, it was reheated to heat up the heating medium. Since the pyrolysis reactor can be downsized and the load on the heater can be reduced, there is an effect that the construction cost can be reduced and the required installation place can be kept small.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of a thermal decomposition method of waste in a waste treatment device according to the present invention.

FIG. 2 is a system diagram of another embodiment of the thermal decomposition method of waste in the waste treatment device according to the present invention.

[Explanation of symbols]

1 Waste Supply Device 2 Pyrolysis Reactor 3 Bucket 4 Crane 5 Input Port 6 Melting Furnace 7 Air Heater 8a, 8b Switching Valve 9 Electric Heater 10, 29 Detector 11 Control Device 12 Memory Device 13 Comparator 14 Computing Device 15 signal generation device 16 discharge device 17 burner 18 cooling device 19 separation device 20 container 21 crusher 22 forced draft fan 23 water tank 24 waste heat boiler 25 dust collector 26 cleaning device 27 chimney 28 power generation device

Claims (7)

[Claims] 1. A pyrolysis reactor in which waste is added and the inside of which is kept at atmospheric pressure or less, and a combustor which combusts the carbonization gas and combustible components discharged from the pyrolysis reactor. In a waste treatment device comprising a heater that generates a heating medium by the combustion gas generated by the combustor and a heating medium line that supplies the heating medium of the heater to the pyrolysis reactor, A waste thermal decomposition method in a waste treatment apparatus, wherein a heating temperature is set to a minimum temperature required for thermal decomposition of waste to be introduced into the thermal decomposition reactor. 2. The thermal decomposition of the waste in the waste treatment device according to claim 1, wherein a reheating device is provided on the downstream side of the heater so that the heating medium can be heated by the reheating device. method. 3. The waste in the waste treatment apparatus according to claim 2, wherein the property of the waste to be put into the thermal decomposition reactor is detected by a detector, and the reheating device is controlled by the signal of the detector. Thermal decomposition method of material. 4. The waste treatment apparatus according to claim 2, wherein the property of the pyrolysis residue discharged from the pyrolysis reactor is detected by a detector, and the reheating device is controlled by a signal from the detector. Of thermal decomposition of waste in Japan. 5. The reheating device according to claim 2, comprising one of an electric heater and a kerosene burner. 6. The heating device is an air heating device, and the heating air obtained by the air heating device is a heating medium.
Pyrolysis method of waste in the described waste treatment equipment. 7. The heating device is a steam heating device, and the heating steam obtained by the steam heating device is a heating medium.
Pyrolysis method of waste in the described waste treatment equipment.