JPH1089644A - Method of operating pyrolysis reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep good processing efficiency of a pyrolysis reactor and easily remove adhered material such as plastics melted and adhered to a heating pipe. SOLUTION: Waste (a) is moved from one end 5a of a main body 3 of a drum to the other end 5b. The waste (a) is heated indirectly by heating air passed from the other end 6a of the main body of the drum to one end 6b and thermally decomposed to generate pyrolysis gas G and pyrolysis residual (b) and at the same time a temperature difference between the waste and the heating air near one ends 5a, 6b of the main body of the drum is detected for every period and a flowing amount of the heating air (h) is increased in respect to a feeding amount of the waste (a) or a temperature of the heating air (h) supplied is increased in response to whether or not the temperature difference exceeds a predetermined value or quantity of heat discharged by the heating air (h) between at least two locations set from the other end 6a to one end 6b of the main body of the drum is decreased than the specified value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to industrial waste such as waste (general waste such as municipal waste from homes and offices, car shredder dust, waste office equipment, electronic equipment, chemical products, etc.). The present invention relates to a method for operating a pyrolysis reactor that heats (including a combustible material) with a heat medium and pyrolyzes.

[0002]

2. Description of the Related Art Conventionally, a pyrolysis reactor which heats waste with a heat medium, for example, heated air, and pyrolyzes the waste, supplies the waste from an input portion thereof, and rotates the drum body by a screw conveyor or the like. And heats it while rotating it along with the rotation of the drum body to cause thermal decomposition to generate a pyrolysis gas and a pyrolysis residue. The pyrolysis gas is discharged from the upper part of the discharge part adjacent to the drum body, and the pyrolysis residue is discharged from the lower part of the discharge part at a temperature of about 450 ° C. The inside of the drum body of the pyrolysis reactor is maintained at a pressure lower than the atmospheric pressure in a low oxygen atmosphere.

[0003]

However, wastes often contain substances such as plastic which are easily melted and easily adhere to the heating pipe. When such waste is thrown in, the plastic or the like melts and adheres to the heating pipe of the heating air passing through the inside of the drum body, especially the heating pipe heat transfer surface on the entrance side of the waste. There is a possibility that the processing efficiency of the decomposition reactor may be deteriorated.

Further, in order to remove the deposits attached to the heating tube, it was necessary to stop the operation of the thermal decomposition reactor and scrape the deposits.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and it is possible to easily remove deposits such as plastics which have melted and adhered to a heating tube, and to maintain good processing efficiency of a thermal decomposition reactor. It is to provide a possible method of operating a pyrolysis reactor.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a heating medium for moving waste from one end of a rotating body to another end and flowing the waste from the other end of the body to one end. Indirectly heats and thermally decomposes the waste,
In a method of operating a pyrolysis reactor that generates a pyrolysis gas and a pyrolysis residue mainly composed of non-volatile components, it is preferable to increase a flow rate of the heat medium relative to the waste at regular intervals. Or increasing the temperature of the heat medium to be supplied. By increasing the flow rate of the heat medium relative to the waste at regular intervals or by increasing the temperature of the heat medium to be supplied, the temperature of the heating pipe that transfers heat to the waste is increased. This promotes the thermal decomposition of the adhered substance that has been melted and adhered, and changes the state to a brittle state with less adherence, thereby facilitating the detachment of the adhered substance from the surface of the heating tube.

Further, the waste is moved from one end to the other end of the rotating body, and the waste is indirectly heated and thermally decomposed by a heat medium flowing from the other end to the one end of the body. In a method for operating a pyrolysis reactor that generates a pyrolysis gas and a pyrolysis residue mainly composed of a nonvolatile component,
Detecting a temperature difference between the waste and the heat medium near one end of the body, and increasing the flow rate of the heat medium relative to the waste when the temperature difference exceeds a predetermined value. Or raising the temperature of the heating medium to be supplied.
By detecting the temperature difference between the waste and the heat medium near one end of the fuselage, the heat transfer efficiency from the heat medium to the waste in the vicinity decreases when the amount of deposits attached to the heating tube increases. Therefore, this temperature difference becomes large, and the degree of adhesion can be understood. When the temperature difference exceeds a predetermined value, heat is transferred to the waste by increasing the flow rate of the heating medium relative to the waste or increasing the temperature of the heating medium to be supplied. The temperature of the heating tube is increased to promote the thermal decomposition of the adhered substance that has melted and adhered, thereby making the substance brittle, and also to facilitate the detachment of the attached substance from the surface of the heating tube.

Further, the waste is moved from one end to the other end of the rotating body, and the waste is indirectly heated and thermally decomposed by a heat medium flowing from the other end to the one end of the body. In a method for operating a pyrolysis reactor that generates a pyrolysis gas and a pyrolysis residue mainly composed of a nonvolatile component,
When the amount of heat released by the heat medium between at least two locations set from the other end to the one end of the body becomes smaller than a prescribed value, the flow rate of the heat medium relative to the waste is reduced. Or increasing the temperature of the heating medium to be supplied. When the amount of heat released by the heat medium between at least two points set from the other end to the one end of the body becomes smaller than a prescribed value, the flow rate of the heat medium relative to the waste is relatively increased. Or, by increasing the temperature of the heating medium to be supplied, the temperature of the heating tube that transfers heat to the waste is increased, and the melting and accelerating the thermal decomposition of the adhered substance to make the adherent brittle,
It makes it easier to remove the deposit from the surface of the heating tube.

Further, in any one of the above-mentioned methods for operating a pyrolysis reactor, the flow rate of the heat medium relative to the waste is increased by reducing the amount of the waste. By reducing the amount of waste input, in addition to the operation of any of the above pyrolysis reactor operating methods, the flow rate of the heat medium can be relatively increased without increasing the capacity of equipment required for heating the heat medium. Can be
The temperature of the heating tube can be raised very quickly.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the method for operating a pyrolysis reactor according to the present invention will be described. In FIGS. 1 to 3, the same structures and working parts are denoted by the same reference numerals.

FIG. 3 is a system diagram of a waste treatment apparatus using the method for operating a pyrolysis reactor according to the present invention. In the waste treatment apparatus 1 of the present embodiment, the waste a such as municipal solid waste is crushed into a 150 mm square or less by a crusher such as a biaxial shearing type, and is charged into the pyrolysis reactor 2 by a conveyor or the like. You.

The waste a charged into the charging section 7 of the pyrolysis reactor 2 passes through a screw feeder 8 having a screw rotated by a motor 9 and a drum body 3 as a body.
Supplied to The drum body 3 tilts toward the outlet side of the waste a and rotates the waste a sequentially as shown in FIG.
The inside of the drum body 3 is maintained in a low oxygen atmosphere at a pressure lower than the atmospheric pressure, and leakage of the atmosphere is prevented by a sealing mechanism (not shown). .

Furthermore, waste a is heated by the heat exchanger (not shown) in the drum main assembly 3 is disposed on the downstream side of the combustion melting furnace 19 is a combustion furnace supplied through the hot air line L ₁ 300 to 6 depending on the heated air h (heat medium)
Heated to 00 ° C, usually around 450 ° C. here,
The heated air h passes through the air heating pipe 4 in the drum main body from the air inlet 11, indirectly heats the waste a, and is discharged from the air outlet 12. Heated air h waste a heated by the thermal decomposition to the pyrolysis gas G _1, becomes the pyrolysis residue b mainly composed of non-volatile components are separated is fed to the discharge unit 10. Although the drum body 3 itself rotates, the cylindrical passage having the air inlet 11 and the air outlet 12 is a fixed portion without rotating.

The pyrolysis gas G separated at the discharge unit 10
₁ is supplied to the burner 20 of the combustion melting furnace 19 via the pyrolysis gas line L _2. Since the pyrolysis residue b discharged from the bottom of the discharge part 10 is relatively high temperature of about 450 ° C., it is cooled to about 80 ° C. by the cooling device 13 and, for example, magnetic separation type, eddy current type, centrifugal type or wind separation It is supplied to a known single or combined separation device 14 such as a formula, where it is separated into a fine-grained combustible component c (including ash) and a coarse-grained non-combustible component d. Collected in the container 15 and reused.

Furthermore, combustible components c is the crusher 16, for example, 1mm milled below, is supplied to the burner 20 of the combustion melting furnace 19 through the combustible component line L _3, from the pyrolysis gas line L ₂ The supplied pyrolysis gas G ₁ and the air for combustion e supplied from the combustion air line L ₄ by the blower 18 are burned in a high temperature range of about 1,300 ° C.
The ash contained in the combustible component c becomes molten slag f, adheres to the inner wall of the combustion and melting furnace 19, further flows down the inner wall, falls from the bottom outlet 21 into the water tank 22, and is converted into slag. .

High-temperature exhaust gas G generated in the combustion melting furnace 19
₂ is a flue gas line L ₅ through a heat exchanger (not shown).
After being recovered by the waste heat boiler 23 and dedusted by the dust collector 26 and further harmful components are removed by the exhaust gas purifier 27,
Via the attraction air blower 28 is discharged from the chimney 30 into the atmosphere becomes low clean gas G ₃ in. Waste heat boiler 23
Is used for power generation by a generator 24 having a steam turbine.

FIG. 1 is a sectional view of an essential part for explaining a method of operating a pyrolysis reactor according to the present invention. As described above, the method of operating the pyrolysis reactor according to the present embodiment moves waste a from one end 5a of the drum body to the other end 5b, and moves the waste a from the other end 6a of the drum body to one end. indirectly waste a pyrolyzed by heated air h circulating the (heat medium) 6b, and generates a pyrolysis residue b consisting mainly non-volatile components and the pyrolysis gases G _1, every period of time, For example, the circulation amount of the heated air h relative to the waste a is increased relatively once a month for about 6 hours, or the temperature of the supplied heated air h is increased.

Further, the temperature difference between the waste a and the heated air h near one end 5a, 6b of the drum body 3, for example, the heated air temperature T ₁ and the waste temperature t ₁ in FIG. _This is to increase the flow rate of the heated air h relative to the waste a when the temperature difference between ₁ and t ₁ exceeds a predetermined value. The heated air temperature T ₁ and the waste temperature t ₁ are not limited to these, and the temperatures at other locations, for example, T ₂ and t ₂ , T ₃ and t ₃ ,... But it ’s fine,
The determination may be made by comprehensively considering the temperature differences at a plurality of locations. The predetermined value for the temperature difference can be obtained in advance from the operating state of the actual machine.

[0019] Then, at least two positions from the other end 6a was set toward the one end 6b of the drum body 3 of the heated air h, for example the temperature difference of the heated air temperature T ₂ and the heating air temperature T _1, the average of this period When the amount of heat released from the heated air h calculated by multiplying the specific heat and the flow rate becomes smaller than a prescribed value, the flow rate of the heated air h relative to the waste a is increased or supplied. This is to raise the temperature of the heated air h. In this case, the heating air temperature T ₂
And not only the temperature difference of the heated air temperatures T _1, heated air temperature T ₁ of the plurality of locations, T _2, T ₃ ... by selecting two appropriate from among may be employed and the temperature difference. However, it is preferable that one of the temperature detecting portions is closer to the one end side 6b from the viewpoint of the adhered portion. The specified value is the same as the predetermined value,
It can be obtained in advance from the operating state of the actual machine.

In the above three operating methods, in order to increase the flow rate of the heated air h relative to the waste a,
Performing by reducing the amount of waste a is advantageous in that it is not necessary to increase the capacity of equipment required for heating the heated air h, and that the temperature of the heating pipe 4 can be increased very quickly.

FIG. 2 shows the temperature of the heated air h and the heated air h
(A) shows the change of the temperature of the heated air h depending on the amount of the deposit on the heating pipe 4 (see FIG. 1) together with the temperature change of the waste a. (B) is a curve diagram showing a change in heat flux from the heated air h to the waste a side. In (A), the curve 33 represents the case where the amount of the deposit on the heating tube 4 is large, and the heating air h
The temperature drop from the drum outlet to the inlet is small,
Accordingly, as shown by the curve 36, the temperature of the waste a gradually rises from the drum inlet to the drum outlet. This is because the heat transmission coefficient is small due to the adhesion of the drum inlet to the heating pipe 4. Curve 34 shows the case where the amount of deposits on the heating pipe 4 is small, and the temperature drop of the heated air h from the drum outlet to the inlet is large. Therefore, as shown in the curve 35, the temperature of the waste a changes from the drum inlet to the outlet. Has become a big rise toward. This is because the influence of the deposits on the heating pipe 4 is small and the heat transmission coefficient is kept large. The effect of the deposits is particularly remarkable near the entrance of the drum main body, where the amount of deposits tends to increase.

In FIG. 2B, the curve 37 corresponds to FIG.
(A) shows the limit value of the heat of section movement when the amount of deposits corresponding to the curve 34 is small, that is, the heat flux. From the entrance to the middle of the drum main body, a substantially constant heat flux is maintained. Has a profile that reduces bundles. Curve 38
Indicates the heat flux when there is a large amount of deposits corresponding to the curve 33 in FIG. 2A, and the heat flux decreases at the drum entrance where the deposits exist. The value of the heat flux is determined by the temperature curves 33 and 34 described above.
Is substantially proportional to a temperature gradient which is a value obtained by differentiating the temperature gradient.

Next, the operation method of the thermal decomposition reactor according to the present embodiment operates as follows. In other words, by increasing the flow rate of the heated air h relative to the waste a at regular intervals or by increasing the temperature of the supplied heated air h, heating that transfers heat to the waste a The temperature of the tube 4 is increased to promote the thermal decomposition of the adhered matter that has been melted and adhered, and to make the material brittle so that the adhered matter can be easily separated from the surface of the heating tube 4.

Further, by detecting the temperature difference between the waste a and the heated air h near the one end 5a of the drum main body, if the amount of the deposit adhering to the heating pipe 4 increases, the temperature difference increases. Therefore, the degree of adhesion can be understood. When the temperature exceeds a predetermined value, heat is transferred to the waste a by increasing the flow rate of the heated air h relative to the waste a or increasing the temperature of the supplied heated air h. Heating tube 4
And promotes the thermal decomposition of the adhered matter that has been melted and adhered, and makes the substance more brittle and makes it easier to peel off the attached matter from the surface of the heating tube 4.

Also, the other end 6a of the drum body to one end 6
When the amount of heat released by the heated air h between at least two points set toward b becomes smaller than a prescribed value, the flow rate of the heated air h relative to the waste a is increased or supplied. By increasing the temperature of the heated air h, the temperature of the heating tube 4 that transmits heat to the waste a is increased, and the thermal decomposition of the adhered matter that has melted and adhered is promoted.
To make the deposits brittle and easy to peel off.

Furthermore, the amount of heat supplied is made relatively excessive by reducing the input amount of the waste a once a month for about 6 hours. As a result, the temperature of the heat transfer surface of the heating pipe 4 on the inlet side of the waste a rises, the pyrolysis of the deposit proceeds, and the material becomes brittle.
It is easy to peel off.

[0027]

According to the operation method of the thermal decomposition reactor of the present invention, the treatment efficiency of the thermal decomposition reactor can be kept good, and the deposits such as plastics, which have melted and adhered to the heating tube, can be easily removed. I can do it.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part for explaining a method of operating a pyrolysis reactor according to the present invention.

FIGS. 2A and 2B show changes in the temperature and the heat flux of the heat medium, FIG. 2A is a curve diagram showing the temperature change of the heat medium along with the temperature change of the waste depending on the amount of deposits on the heating tube, and FIG. FIG. 4 is a curve diagram showing a heat flux from a medium to waste.

FIG. 3 is a system diagram of a waste treatment apparatus using the operation method of the thermal decomposition reactor of the present invention.

[Explanation of symbols]

1 waste disposal device 2 pyrolysis reactor 3 the drum body (fuselage) 5a, 6b at one end 5b, 6a end side G ₁ pyrolysis gas a waste b pyrolysis residue c combustible component d unburned component h heating Air (heat medium)

Claims (4)

[Claims] The waste is moved from one end to the other end of the rotating body, and the waste is indirectly heated and thermally decomposed by a heat medium flowing from the other end to the one end of the body. A method for operating a pyrolysis reactor that generates a pyrolysis gas and a pyrolysis residue mainly composed of a non-volatile component, wherein a flow rate of the heat medium relative to the waste is increased at regular intervals. Or a method for operating a pyrolysis reactor, wherein the temperature of the supplied heat medium is increased. 2. The waste is moved from one end to the other end of the rotating body, and is indirectly heated and thermally decomposed by a heat medium flowing from the other end to the one end of the body. A method for operating a pyrolysis reactor that generates a pyrolysis gas and a pyrolysis residue mainly composed of non-volatile components, wherein a temperature difference between waste and a heat medium near one end of the body is detected, and the temperature difference is detected. When the value exceeds a predetermined value, the flow rate of the heat medium relative to the waste is increased or the temperature of the heat medium to be supplied is increased. how to drive. 3. The waste is moved from one end to the other end of the rotating body, and the waste is indirectly heated and thermally decomposed by a heat medium flowing from the other end to the one end of the body. In the method for operating a pyrolysis reactor that generates a pyrolysis gas and a pyrolysis residue mainly composed of a non-volatile component, a heat medium is provided between at least two locations set from the other end to the one end of the body. Pyrolysis characterized by increasing the flow rate of the heat medium relative to the waste or increasing the temperature of the heat medium to be supplied when the amount of heat to be released becomes smaller than a prescribed value. How to operate the reactor. 4. The thermal decomposition according to claim 1, wherein a flow rate of the heat medium relative to the waste is increased by reducing an amount of the waste. How to operate the reactor.