JP2009243859A - Indirect heating pyrolysis device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely obtain self-cleaning effect against plastic adhesion by setting a space between adjacent heat transfer pipes to have a dimension for letting a processing object easily pass through the space in an area where a problem of plastic fusion/adhesion likely generates. <P>SOLUTION: The heat transfer pipes 2, 2', each of which has a small diameter part in one third area equivalent to a center part in the whole area from an inlet to an outlet of a pyrolysis drum 1 and has large diameter parts in one third area on the inlet side and in one third area of the outlet side, are provided in the pyrolysis drum 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thermal decomposition apparatus for thermally decomposing waste (object to be treated), and more particularly to an indirect heating type thermal decomposition apparatus suitable for thermal decomposition of waste with a high plastic content such as car shredder dust. It is.

  As a thermal decomposition apparatus suitable for thermal decomposition treatment of waste having a high plastic content, for example, the one described in Patent Document 1 can be cited. This thermal decomposition apparatus is equipped with a rotary kiln.

  FIG. 5 shows a schematic longitudinal sectional view of a rotary kiln as an example of a thermal decomposition apparatus. The rotary kiln is a horizontal rotary drum type pyrolysis furnace, and comprises a pyrolysis drum 3 that performs a pyrolysis process on the processing object A, and supports 13 and 14 that rotatably support the pyrolysis drum 3. And a discharge device 18 that discharges the pyrolysis gas and the pyrolysis residue generated by the heat treatment. The processing object A introduced from the inlet 4 side of the pyrolysis drum 3 is pyrolyzed by being heated while slowly moving to the outlet 5 side as the pyrolysis drum 3 rotates.

The pyrolysis drum 3 has a large number of heat transfer tubes 16 along the inner wall surface 17 thereof. The heat transfer tube 16 is configured such that a high-temperature heating gas G that is a heating medium flows in a counterflow with respect to the moving direction of the processing object A. That is, the heating gas G has a heating gas inlet 8 on the outlet 5 side of the pyrolysis drum 3 and a heating gas outlet 9 on the inlet 4 side of the pyrolysis drum 3. When the high-temperature heating gas G passes through the heat transfer tube 16 in this counterflow, the internal processing object A is indirectly heated and thermally decomposed.
JP 2003-321573 A

  Here, in the case of processing industrial waste, especially car shredder dust (hereinafter referred to as “ASR”), compared with the case of processing general waste such as municipal waste, there are the following problems. Arise. In other words, ASR consists of combustible materials such as plastics, fibers, urethane foam, and other non-combustible materials such as metal and glass, which constitute parts such as automobile seats and instrument panels. It has the property of being large.

  The temperature of the heated gas flowing through the heating tube 16 for the thermal decomposition is usually about 500 ° C. to 550 ° C. on the inlet 8 side of the heating tube 16 (the outlet 5 side of the thermal decomposition drum 3). The temperature of the heated gas G flows through the heating pipe 16 toward the outlet 9 (the inlet 4 side of the thermal decomposition drum 3), and during that time, the heat is absorbed by the processing object A, and the temperature gradually decreases. The temperature profile L1 as shown in FIG. That is, the temperature drops to about 280 ° C. to 300 ° C. at the outlet 9 (the inlet 4 side of the pyrolysis drum 3).

  On the other hand, the processing object A is introduced into the pyrolysis drum 3 from the inlet 4 of the pyrolysis drum 3 at room temperature (about 20 ° C.) and indirectly heated by the counterflowing heating gas G flowing in the heat transfer tube 16 and gradually. The temperature rises and reaches about 430 ° C. to 500 ° C. at the outlet 5 of the pyrolysis drum 3. FIG. 6 shows a temperature profile L2 of the processing object A.

  As shown in FIG. 6, the temperature of the object A to be processed is 200 ° C. to 400 ° C. in a region M that is approximately one third of the central portion in the entire region from the inlet 4 to the outlet 5 of the pyrolysis drum 3. Become. In the case where the processing object A has a large proportion of plastic such as ASR, in this temperature region M, the plastic adheres to the inner wall surface 17 (surface of the heat transfer tube 16) of the pyrolysis drum 3 without being completely decomposed, A growing problem occurs. This problem reduces the efficiency of the pyrolysis process and makes it difficult to continue operation.

  Therefore, the interval between the heat transfer tubes 16 is increased, that is, the heat transfer tubes 16 themselves are narrowed, so that the plastic fixed to the heat transfer tubes 16 is peeled off with other wastes such as metal (self-cleaning function). ). That is, by making the interval between the heat transfer tubes 16 wide, a large and hard metal can pass between the heat transfer tubes 16, and the metal and the plastic fixed to the heat transfer tubes 16 are brought into contact with each other to make the plastic the heat transfer tubes 16. I'm trying to peel it off.

  However, if the interval between the heat transfer tubes 16 is increased as described above, that is, if the heat transfer tubes 16 themselves are made thinner, the sticking of the plastic to the heat transfer tubes 16 is reduced, but the heat transfer tubes 16 themselves become thinner, so that a large The thermal area cannot be ensured, and the processing capacity of the thermal decomposition apparatus itself is reduced.

  Moreover, if the space | interval of the heat exchanger tubes 16 is taken wide, it will become impossible to arrange heat exchanger tubes 16 closely, and also has the fault that a thermal decomposition apparatus enlarges.

  The present invention has been made in view of such circumstances, and its purpose is to set the interval between adjacent heat transfer tubes to a size that allows the object to be processed to easily pass in an area where the problem of plastic melt adhesion is likely to occur. An object of the present invention is to ensure the self-cleaning effect on the adhesion of plastic.

In order to solve the above problems, a first aspect of the present invention is an indirect heating type pyrolysis comprising a pyrolysis drum and a plurality of heat transfer tubes provided along an inner wall surface of the pyrolysis drum. A device,
The heat transfer tube is composed of a different diameter tube having a small diameter portion and a large diameter portion.

  According to the present invention, since the heat transfer tube having the small diameter portion and the large diameter portion is used, a region (small diameter portion) having a large overall length in the interval between the adjacent heat transfer tubes is provided around each one heat transfer tube. And a small region (large diameter portion) can be formed. Therefore, even if the object to be processed gets stuck or the plastic adheres to an area where the interval is small, the object to be caught or the attached plastic is elongated by the force moving from the inlet to the outlet in the object to be decomposed. It can move in a direction and move to a region with a large interval, where it can be easily removed. Thereby, while improving a heat transfer area (large diameter part), the effect of being able to reduce the problem of a catch and plastic adhesion (small diameter part) is acquired.

  According to a second aspect of the present invention, there is provided an indirect heating type pyrolysis apparatus comprising a pyrolysis drum and a plurality of heat transfer tubes provided along an inner wall surface of the pyrolysis drum, wherein the heat transfer tube In the entire region from the inlet to the outlet of the pyrolysis drum, about one third of the central portion is a small diameter portion, about one third of the inlet side and about three minutes of the outlet side. The region 1 is a different diameter tube which is a large diameter portion.

The problem of plastic melt adhesion occurs in the region about one third of the central portion of the entire region from the inlet to the outlet of the pyrolysis drum.
However, according to the present invention, since the outer diameter of the heat transfer tubes is formed small in this region, the interval between the adjacent heat transfer tubes can be easily set to a dimension that allows easy passage of the processing object. A self-cleaning effect against adhesion can be reliably obtained.

  On the other hand, about one third of the region on the inlet side and about one third of the region on the outlet side hardly cause the problem of plastic melt adhesion. Therefore, the heat transfer efficiency can be increased by setting the outer diameter dimension of each heat transfer tube to be large, so that the decomposition ability of the entire thermal decomposition apparatus can be increased as compared with the conventional one while reducing the problem of plastic adhesion. Can do.

  A third aspect of the present invention is the indirect heating type thermal decomposition apparatus according to the first or second aspect, wherein the range of the small diameter portion is a region where the temperature of the heat transfer tube is about 200 ° C to 400 ° C. It is characterized by being.

  The problem of plastic melt adhesion occurs in the region where the temperature of the heat transfer tube is about 200 ° C to 400 ° C. According to the present invention, since the interval between the heat transfer tubes is large in this temperature region portion, the self-cleaning effect against the plastic adhesion can be reliably obtained.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In addition, this invention is not limited to the following embodiment.

[First embodiment]
1 is a longitudinal sectional view in the longitudinal direction of a thermal decomposition drum 1 of a thermal decomposition apparatus according to the present invention, FIG. 2 is an enlarged view of a heat transfer tube 2 at portions D and E in FIG. 1 of the thermal decomposition apparatus according to the present invention, 3A is a cross-sectional view taken along the line XX in FIG. 1, and FIG. 3B is a cross-sectional view taken along the line YY in FIG.

In FIG. 1, an object to be processed is input from the left side of the drawing, processed in a thermal decomposition apparatus, and discharged to the right side.
The pyrolysis drum 1 is divided into three zones A to C. Here, the zones A and C are portions where the plastic hardly adheres to the heat transfer tube 2, and the B zone is a zone where the plastic easily adheres to the heat transfer tube 2 '.

In the A zone, since the processing temperature is low, the plastic is not yet melted. Therefore, it is difficult for plastic to adhere to the heat transfer tube 2.
In the B zone, the processing temperature gradually rises to a temperature exceeding the melting point of the plastic. For this reason, the plastic easily adheres to the heat transfer tube 2.
In the C zone, the processing temperature is the highest and the temperature at which the plastic has already decomposed is reached, so that it is difficult for the plastic to adhere to the heat transfer tube 2.
In addition, B zone occupies about 1/3 of the center part of the whole with respect to the length of the pyrolysis drum 1. The A and C zones occupy about 1/3 on the entrance side and about 1/3 on the exit side, respectively.

  Therefore, in the zones A and C, plastic does not easily adhere to the heat transfer tube 2, so that the interval b between the heat transfer tubes 2 does not have to be wide. In this zone, the heat transfer area is increased by using a tube thicker than the heat transfer tube 2 used in the conventional pyrolysis apparatus.

  On the other hand, in the B zone, plastic easily adheres to the heat transfer tube 2, so that it is necessary to widen the interval c between the heat transfer tubes 2 '. Therefore, in this zone, the thin heat transfer tube 2 'used in the conventional pyrolysis apparatus is used as it is.

  By using the thin heat transfer tube 2 ′, it is possible to prevent the plastic from adhering to the heat transfer tube 2 ′. Even if the plastic adheres to the heat transfer tube 2 ′, the heat transfer tube 2 ′ is obtained by the self-cleaning function. It becomes possible to peel the plastic from.

2D is an enlarged view of the heat transfer tubes 2 and 2 ′ at the boundary between the A zone and the B zone, and FIG. 2E is an enlarged view of the heat transfer tubes 2 and 2 ′ at the boundary between the B zone and the C zone. It is shown.
Since D and E have the same dimensions and shape, only D will be described and description of E will be omitted.

  For example, in the case of the heat transfer tube 2 (outer diameter 89.1 mm) having the large diameter portion, the heat transfer tubes 2 and 2 ′ are connected by inserting the heat transfer tube 2 ′ (outer diameter 76.3 mm) having the small diameter portion. .

  When the interval between adjacent heat transfer tubes is indicated by specific numerical values, a = 12.5 mm, b = 23.4 mm, and c = 36.2 mm.

  Therefore, the interval b between the large-diameter heat transfer tubes 2 in the A zone is smaller than the interval between the small-diameter heat transfer tubes c in the B zone, and the heat transfer area can be increased in the A zone. The zone has a structure capable of preventing adhesion of plastic.

  Here, when the heat transfer tube 2 ′ (outer diameter 76.3 mm) having the above-mentioned small diameter portion is used for the entire length of the pyrolysis drum 1, and the B zone (the center of the total length) where the plastic easily adheres as in the present invention. Heat transfer tube 2 '(outer diameter 76.3mm) with a conventional small diameter part is used for the length of about 30% of the part), and the A and C zones where the plastic is difficult to adhere (from the total length to the B zone length) Comparison of the heat transfer area when using the heat transfer tube 2 (outer diameter 89.1 mm) having a large diameter portion (the length of the remaining portion of about 70%) is performed.

Since the heat transfer area is proportional to the outer diameter of the heat transfer tube, the heat transfer tube 2 (outer diameter 89.1 mm) having the large diameter portion is 1.168 of the heat transfer tube 2 ′ (outer diameter 76.3 mm) having the small diameter portion. Double (89.1 / 76.3)
It has the heat transfer area.

When the heat transfer tube 2 ′ having the above-mentioned small diameter portion (outer diameter 76.3 mm) is used for the entire length of the pyrolysis drum 1, the case of the present invention has a central portion of about 30% (calculation). The heat transfer tube 2 '(outer diameter 76.3 mm) having a small diameter portion in the B zone that occupies 0.3) is used, and A and C occupy about 70% of the total length (0.7 in the calculation). Since the heat transfer tube 2 (outer diameter 89.1 mm) having a large diameter portion in the zone is used,
0.3 × 1 + 0.7 × 1.168 = 1.12, increasing the heat transfer area by about 10% compared to the case of using a heat transfer tube 2 ′ (outer diameter 76.3 mm) with a conventional small-diameter portion over its entire length. Can be made.

  That is, even if the length of the heat transfer tube is shortened by about 10%, the performance equivalent to that of the conventional pyrolysis drum can be maintained, so that the apparatus itself can be downsized.

[Second Embodiment]
As the second embodiment, as described in FIG. 4, for example, the heat transfer tube 2 (outer diameter 89.1 mm) having a large diameter portion and the heat transfer tube 2 ′ (outside diameter) having a small diameter portion in the first embodiment. This is a form in which a heat transfer tube in which the heat transfer tubes 2 and 2 ′ are integrally formed is used without a connecting portion having a diameter of 76.3 mm.
If it is this aspect, since there is no coupling | bond part, it will become possible to increase the intensity | strength of a heat exchanger tube.

  Regardless of the first and second embodiments, the size of the heat transfer tube, the position of the small-diameter portion and the large-diameter portion of the heat transfer tube can be appropriately set depending on the scale of the apparatus and the type of the processed material.

The longitudinal cross-sectional view in the longitudinal direction of the thermal decomposition drum 1 of a kiln thermal decomposition apparatus. The enlarged view of the heat exchanger tube 2 of the part of D and E in FIG. 1 of the kiln decomposition | disassembly apparatus which concerns. Sectional drawing of XX in FIG. 1, and sectional drawing of YY. The longitudinal cross-sectional view in the longitudinal direction of the heat exchanger tube in 2nd Embodiment. The schematic longitudinal cross-sectional view of a rotary kiln. Temperature profile

Explanation of symbols

1 Pyrolysis drum 2, 2 'Heat transfer tube
10 Pyrolysis drum

Claims (3)

An indirect heating type pyrolysis apparatus comprising a pyrolysis drum and a plurality of heat transfer tubes provided along an inner wall surface of the pyrolysis drum,
The indirect heating type thermal decomposition apparatus, wherein the heat transfer tube is composed of a different diameter tube having a small diameter portion and a large diameter portion. An indirect heating type pyrolysis apparatus comprising a pyrolysis drum and a plurality of heat transfer tubes provided along an inner wall surface of the pyrolysis drum,
In the heat transfer tube, a region of about one third of the central portion in the entire region from the inlet to the outlet of the pyrolysis drum is a small diameter portion, and a region of about one third of the inlet side and about a portion of the outlet side. An indirect heating type thermal decomposition apparatus characterized in that a third of the region is a different diameter pipe having a large diameter portion. An indirect heating type pyrolysis apparatus according to claim 1 or 2,
The range of the small diameter portion is an area where the temperature of the heat transfer tube is about 200 ° C. to 400 ° C.

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