JPH1036852A - Carbonization thermal decomposition reactor for waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbonization thermal decomposition reactor for waste which has a simplified structure by constituting a reactor body from a cylinder comprising a plurality of parallel arrayed heating tubes and a fin for connecting the heating tubes to each other. SOLUTION: A reactor body 1 comprises a cylindrical barrel section 19, a plurality of heating tubes arranged parallel to one another within the barrel section, a fin for connecting the heating tubes to each other, and a shelf-like projection section. The heating tube and the end section of the fin are supported and fixed, so as to be hermetically sealed, onto a tube plate 8 for closing both side portions of the reactor body 1. Thus, a carbonization thermal decomposition reactor is provided. A waste A is introduced through a feed port 4 into the reactor body 1 where it is heated, in an oxygen-shielded state, to about 400 to 500 deg.C by a heating gas G flowing through the heating tubes. The waste A stays in the reactor body 1 for about one hr while undergoing agitation and mixing by rotation and consequently is thermally decomposed. As a result, about 75wt.% carbonization gas B and about 25wt.% thermal decomposition residue C are produced. The rotation of the body 1 permits the carbonization-gas B to be introduced through an outlet 16 into a melt combustion apparatus. On the other hand, the thermal decomposition residue C is discharged from an outlet 17 and classified into fine particles and coarse particles, and the fine particles are stored in a silo.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a dry distillation pyrolysis reactor for waste such as municipal waste, and is mainly used for dry distillation pyrolysis melting and burning of waste such as municipal waste. .

[0002]

2. Description of the Related Art FIG. 6 shows an outline of a conventional reactor body used for dry distillation pyrolysis of waste, and FIG. 7 shows an example of an arrangement of heating tubes in the reactor body. 6 and 7, 1 is a cylindrical reactor main body, 2 is a heated gas inlet, 2a is a heated gas inlet casing, 3 is a heated gas outlet casing, 3a is a heated gas outlet casing, and 4 is a waste supply port. Reference numeral 5 denotes a pyrolysis product outlet, 6 denotes a cylindrical body made of a steel plate, 7 denotes a heating tube, 8 denotes a tube plate, 8a denotes a support plate, and 9 denotes a bellows mechanism.

[0003] Thus, the reactor body 1 is connected to the waste supply port 4.
The to-be-dried material (waste) A supplied to the inside is heated to a temperature of 400 ° C. to 500 ° C. by the high-temperature heating gas G flowing through the heating pipe 7 while shutting off the air, thereby forming a so-called dry distillation heat. Decomposed and converted to pyrolysis products.

The pyrolysis products formed in the reactor main body 1 are sequentially fed out to the pyrolysis product outlet 5 side with the rotation of the reactor main body 1, and are carbonized in a separation / conveyance device (not shown). After being separated into the gas B and the pyrolysis residue C, the former carbonized gas B is introduced into a melting and burning apparatus (not shown). Further, the latter pyrolysis residue C is taken out from a separation / carrying-out device (not shown), and then supplied to a melting and burning device (not shown) through a process of removing incombustibles and a process of pulverizing solid combustibles. It is melted and burned at a temperature of about 1200 ° C. together with the gas B.

When the waste A is heated by the heating gas G flowing through the heating pipe 7 and pyrolyzed by pyrolysis, the heat energy of the heating gas G is appropriately and effectively applied to the waste. It is important to communicate to A. That is, the overall transfer coefficient of heat transmitted from the heating gas G to the waste A through the tube wall of the heating tube 7 is increased, and the waste A is heated as uniformly as possible to a required temperature, and the dry distillation heat is evenly distributed. Decomposition is an essential requirement.

Further, since the pyrolysis of the waste A must be carried out almost in the absence of oxygen, the reactor body 1 is required to have a high degree of hermeticity, and the tube plate 8 supporting the heating tube 7 and the heating tube 7 are required. In the sealing property between the heating gas G and the heating gas G passing through the heating pipe 7 while the inside of the reactor body 1 is in a reducing atmosphere.
Because of the oxidizing atmosphere, strict control is required.
This is because there is a large temperature difference between the temperature inside the reactor body 1 and the temperature of the heated gas passing through the heating pipe 7, so that the reactor body 1 and the heating pipe 7 have different amounts of thermal expansion, and the sealing property is different. In addition, if oxygen leaks, it is not only adversely affecting the carbonization performance and carbonization products, but also corrosive substances such as hydrogen chloride gas contained in carbonization gas B, This is because severe corrosion occurs in the reactor body 1 including the heating tube 7 in an oxidizing atmosphere.

For this reason, in the conventional reactor body 1 for this type of dry distillation pyrolysis, one end of each heating tube 7 is connected to a tube sheet 8 as shown in FIGS. The heating pipes 7 are fixed by welding, and the other end of each heating pipe 7 is provided with an extendable bellows mechanism 9 so that the heating pipe 7 can be moved relative to the tube sheet 8 via the bellows mechanism 9. It is designed to support.

However, if one end of each of the heating tubes 7 is supported and fixed via the bellows mechanism 9, the manufacturing cost of the reactor body 1 increases, and the bellows mechanism 9 is
Since it is made of a thin metal, there is a problem that damage is apt to occur due to an unexpected shearing force, and it takes time to repair it.

Further, in the conventional reactor body 1, since the waste A in the vicinity of the inner peripheral surface of the steel body 6 needs to be heated evenly,
The heating tube 7 is relatively arranged near the inner peripheral surface of the body 6. Therefore, the gap S between the inner peripheral surface of the body and the heating tube 7 (outermost heating tube) located at a position close to the inner surface is relatively narrow, and the blind spot in which the waste A is not easily replaced is easily formed. ing. As a result, while the operation of the reactor body 1 is continued, the waste A is sealed in the gap S and carbonized as it is, and the dry distillation pyrolysis space in the reactor body 1 is cleaned. It is extremely difficult to maintain the state, and there is a problem that the surface of the outermost heating tube facing the body 6 does not function as a heat transfer surface to the waste A. Furthermore, since there is a gap between the heating tubes arranged radially, a linear waste such as a cord or a wire is entangled, and the growth of the entanglement closes the gap, thereby reducing the heat transfer surface. Problems arise.

[0010]

SUMMARY OF THE INVENTION In the present invention, it is extremely difficult to secure the sealing property between the heating tube 7 and the tube sheet 8 as described above in the reactor body 1 of the conventional dry distillation pyrolysis reactor. In addition, the manufacturing cost of the carbonization pyrolysis reactor cannot be significantly reduced, and the repair and management of the reactor body 1 is troublesome, and the carbonization pyrolysis space in the reactor body 1 is kept clean. It is difficult to hold the space between the inner peripheral surface of the cylindrical body 6 and the outermost heating tube 7 because the solid thermal decomposition product blocks the space between the inner surface and the outermost heating tube 7. The pyrolysis of the waste A can be smoothly and efficiently achieved, and the airtightness between the heating pipe 7 and the tube sheet 8 can be reliably ensured for a long period of time. Is simple and has excellent processing and assemblability.
An object of the present invention is to provide a reactor for pyrolysis of waste, which has enabled a significant reduction in production costs.

[0011]

SUMMARY OF THE INVENTION The present invention relates to a dry distillation heat source for waste, in which a heating gas is circulated through a heating pipe, and the material to be dried in the cylindrical reactor body is heated by the heat of the heating gas. In the cracking reactor, the basic configuration of the present invention is that the reactor body is formed in a cylindrical shape from a plurality of heating tubes arranged in parallel and fins connecting adjacent heating tubes. .

With the above configuration, in the dry distillation pyrolysis reactor of the present invention, the amount of expansion in the major axis direction of the reactor body and the amount of expansion in the major axis direction of the heating tube itself become the same, There is no stress due to the difference in the amount of expansion between the tube and the tube plate supporting and fixing both ends of the heating tube. As a result, it is extremely easy to secure the airtightness of the dry distillation pyrolysis zone of the reactor body 1. Further, unlike the conventional reactor body, solid thermal decomposition products are not pinched between the inner peripheral surface of the cylindrical barrel and the outermost heating tube, and the dry distillation heat of the reactor body is eliminated. The decomposition zone can be kept very clean.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic explanatory view of a dry distillation pyrolysis reactor according to the present invention, and portions common to FIGS. 6 to 9 showing a conventional example are denoted by the same reference numerals. In FIG. 1, 1 is a reactor body, 2 is a heated gas inlet, 2a is a heated gas inlet casing, 3 is a heated gas outlet casing, 3a is a heated gas outlet casing, 4 is a waste supply port, and 5 is a pyrolysis product. A product outlet, 19 is a cylindrical body, 7 is a heating tube, 7a is a fin, 8 is a tube plate, 8a is a support plate, 10 is a refuse supply feeder, 11 is a reactor main body support base, 12 is a support roller, and 13 is a support roller. Rotary drive device, 14 is a gear, 15 is a separation carrying-out device, 16 is a carbonization gas outlet, 17 is a carbonization residue outlet,
Reference numeral 18 denotes a support base.

The reactor main body 1 comprises a cylindrical body 19 comprising a plurality of heating tubes 7 and fins 7a, and a plurality of heating tubes 7, fins 7a and a support plate 8a disposed therein. And a plurality of shelf-shaped protruding portions 20. That is, the cylindrical body 19 has a plurality of heating tubes 7 arranged in a circle as shown in FIG. 2, and the adjacent heating tubes 7 are formed into a flat plate having the same length as the heating tubes 7 having an appropriate width. It is formed by connecting mutually by welding or the like via the fin 7a. Further, the shelf plate-shaped protruding portion 20 arranges a plurality of heating tubes 7 linearly inward from the body portion 19 and connects the adjacent heating tubes 7 to each other by welding via fins 7a. It is formed by doing.

The cylindrical body portion 19 and the shelf-shaped projecting portion 20
The ends of each of the heating tubes 7 and fins 7a which form the pipe are fixed to the tube sheet 8 by welding as shown in FIG.
The cylindrical space formed by the tube sheet 8 and the tube sheet 8 becomes a space for dry distillation pyrolysis of the waste A. Further, on both outer sides of the tube sheet 8, a space portion 23 composed of the end plate 21, the short cylindrical body 22 and the tube sheet 8 is formed, one of which is a receiving portion for high-temperature heating gas, and the other is for receiving low-temperature heating gas. Each functions as a discharge unit.

The body 19 is formed from the heating tube 7 and the fin 7a by welding the heating tube 7 and the fin 7a to form a flat plate, and thereafter bending the plate into a cylindrical shape. From the beginning, there is a method in which the heating tube 7 and the fins 7a are arranged in a circular shape and they are sequentially welded to form a cylindrical body, but in the present embodiment, the former method is adopted. ing.

The heating tube 7 and the fin 7a may be independently welded to the heating tube 7 and the fin 7a, or they may be welded to each other using a finned heating tube. Thus, a cylindrical body may be used. In the present embodiment, the cylindrical body 19 is formed by welding independent heating tubes and fins.

On the outer peripheral surface of the cylindrical body 19 comprising the heating tube 7 and the fin 7a, a bending stress reduction caused by the weight of the heating tube, the mounting hardware, and the waste acting on the support portion of the heating tube support plate 8a is provided. And a reinforcing ring 25 for reducing bending stress and shear stress generated by the weight of the drum acting on the roller receiving portion, a reinforcing ring 26 for the gear receiving portion, and the like are appropriately provided. The mechanical strength of the trunk 19 is improved.

The shelf-like projections 20 composed of the heating tubes 7 and the fins 7a are reinforced by providing support plates 8a at appropriate intervals. Note that the shelf plate-shaped projecting portion 20
In addition to heating the material to be distilled A, the material to be dried A is stirred up by lifting the material to be dried A inside when rotating the body portion 19 and then dropping it. is there.

FIG. 4 illustrates an example of a plant for dry distillation pyrolysis melting and burning of waste using the waste carbonization pyrolysis reactor according to the present invention. Referring to FIG. 4, waste A carried in by a truck or the like first has a waste pit 31.
Is stored in The waste pit 31 has a capacity enough to maintain normal operation of the melting and burning treatment plant even if the introduction of the waste A is interrupted for several days. Pit 31
The waste A inside is reduced to about 1 by the rotary shredder 32.
After being crushed to a size of 50 mm or less, the crane 33
Is transferred to the hopper 35 of the reactor main body 1 via the feeder 10, and is sequentially supplied into the main body 1 by the feeder 10. still,
At this time, the sewage sludge stored in the sewage sludge tank 34 is also supplied into the hopper 35 as necessary.

The waste A and the like supplied into the main body 1 are heated from normal temperature to 400.degree.
(The center temperature is about 450 ° C.) and stays in the main body 1 for about 1 hour while being stirred and mixed by rotation.

The main body 1 is rotatably supported at an inclination angle of about 1.5 degrees with respect to the horizontal, with the inlet side positioned upward and the outlet side positioned downward. 3R
The rotation is driven at the rotation speed of PM. As a result, the waste A in the main body 1 is thermally decomposed during this time, and the dry distillation gas B and the solid pyrolysis residue C are generated in the main body 1.

The thermal decomposition of the waste A in the main body 1 is usually completed in about one hour, and approximately 75 wt% of the dry distillation gas B and 25 wt% of the thermal decomposition residue C are generated. Also,
The generated pyrolysis residue C is almost completely homogenized by being stirred and mixed in the main body 1, and becomes particles of a uniform size.

The carbonized gas B and the pyrolysis residue C in the reactor main body 1 are discharged into the separation / conveying device 15 adjacent to the main body 1 as the main body 1 rotates, and the carbonized gas B separated here is separated. Is supplied to the melting and burning device 40 to perform so-called melting and burning. In addition, the pyrolysis residue C is obtained from the vibration conveyor 41.
After the above is cooled from a temperature of about 450 ° C. to a temperature of about 80 ° C., it is classified by the separator 42 into fine particles and coarse particles.
The classified coarse particles 27 contain a large amount of incombustible substances such as sand, glass, and metal, which are separated so as to be recyclable (not shown).

As the separator 42, a sieve having a size of 5 mm is usually used, and the fine particles 28 passing through the sieve are temporarily stored in a silo 44. In addition, about 30-
Forty percent consists of solid carbon.

Of the fine particles 28, those having a particle size of 1 mm or more are atomized by a roller crusher 43,
Is stored together with the fine particles 28. And silo 44
The fine particles 28 in the inside are sent to the melting and burning device 40 by pneumatic transportation, and are burned together with the carbonization gas B. The use of the separator 42 increases the amount of carbon in the fine particles by about 30%.
As a result, the calorific value is about 10,000 kj / kg.

The fine particles 28 containing the carbonized gas B and carbon are burned at about 1300 ° C. in the melting and burning apparatus 40 and enter the gas cooling chamber 45. Since this combustion temperature is 100 to 150 ° C. higher than the melting point of the ash, the slag 29 exits the molten combustion device 40 in a molten state and becomes a water-cooled slag.

Since the water-cooled slag 30 is inert,
In this state, it can be disposed or used as valuables. Further, in the melting and burning apparatus 40, all organic substances are destroyed by the temperature and the residence time. Furthermore, various known means for maintaining good combustion, such as an exhaust gas reburning method combined with the supply of multi-stage combustion air and a cyclone combustion method, can be used or combined with the melt combustion apparatus 40. . For example, by setting the average excess air ratio λ = 1.3, the uniform temperature distribution in the combustion chamber and the stirring effect
Complete combustion in low NOx conditions can be achieved. As a result, unburned carbon in slag is 0.2% (weight)
It can be suppressed below.

The heat energy in the exhaust gas is transferred to a waste heat boiler 46.
And is used for power generation by the power generation equipment 47 and district heating. By the heat recovery by the waste heat boiler 46,
The exhaust gas temperature is cooled to about 200 ° C. Further, the exhaust gas is thereafter processed by a dust collecting device 48 such as a bag filter or an electric dust collector to remove dust components. Further, the removed dust is returned to the melting and burning device 40 to be melted and burned, and is taken out as slag.

The exhaust gas is further subjected to a known exhaust gas treatment device 4.
9 For example, harmful substances such as HCl and SO ₂ are removed by washing with a scrubber or the like. Further, the exhaust gas is supplied to, for example, a NOx removal device using a selective catalytic reduction method, an activated carbon adsorption tower 4 or the like.
After the dioxins have been removed through 9 and so on, the chimney 5
It is released to the atmosphere from zero.

Waste A in the dry distillation pyrolysis reactor 1
In general, fossil fuel combustion gas is used as a heating medium for heating, and this high-temperature heating gas G passes through a heating pipe 7 installed in the reactor body 1 to indirectly heat the waste A. .

FIG. 5 is a piping diagram showing the flow of the high-temperature heating gas G for heating the waste A in the reactor body 1. The loop path of the high-temperature heating gas G is the heating gas inlet 2, the heating pipe 7,
It comprises a heating gas outlet 3, a loop pipe 36, a blower 37, a heat exchanger 38, a burner heater 39 and the like.

The heating gas G heated to 500 to 600 ° C. (usually 520 ° C.) enters the heating pipe 7 from the heating gas inlet casing 2 a adjacent to the outlet of the reactor body 1,
Heat energy is supplied to the waste A while passing through the heating pipe 7 to reach a temperature of 250 to 350 ° C. (normally 300 ° C.) and into the heated gas outlet casing 2 b adjacent to the inlet of the reactor body 1. It enters and is led out from here to the loop pipe 36.

A blower 37 for circulating the heating gas G, a heat exchanger 38 for heating the gas, and a burner heater 39 are provided in the loop pipe 36. A generally known shell-and-tube heat exchanger is used as the heat exchanger 38. Superheated steam of about 400 ° C. is taken out from the waste heat boiler 46, and the heating gas is indirectly heated by this. The temperature of the heated gas returned from the outlet casing 2b is raised to about 360 ° C. The superheated steam used for heating the heating gas is returned to the waste heat boiler 46 again. Further, the loop pipe 36 is provided with a bypass pipe 36a that bypasses the heat exchanger 38, and is used when steam is not supplied yet at the time of starting the plant.

The heated gas G heated to about 360 ° C. in the heat exchanger 38 enters a burner heater 39, where it is usually heated to 520 ° C. by direct combustion of fossil fuel (usually gas) or oil.
Heated. In addition, fresh air preheated to about 200 ° C. by the air preheater 51 is supplied through a pipe 52 for fossil fuel combustion.

The combustion gas burned by the burner heater 39 circulates in the loop pipe, and acts as a heat medium for heating the waste. Since this gas is not corrosive, the inner wall of the heating tube 7 is not corroded. Further, since this gas is increased by an amount corresponding to the combustion gas generated in the burner heater 39, the excess gas is extracted through the pipe 53 and the chimney 5
Release to zero. Since this gas has a temperature of about 300 ° C., it is used for heating the combustion air for the burner heater 39 by the air preheater 51.

[0037]

According to the present invention, since the cylindrical body of the reactor body is formed by the structure in which the heating tube and the fin are connected, the thermal expansion of the body itself is caused by the heat of the heating tube itself. It becomes swelling. As a result, in order to avoid the adverse effect on the airtightness due to the difference in thermal expansion between the body and the heating tube as in the conventional reactor body, consideration was given to using a bellows mechanism at the connection between the heating tube and the tube plate. Is completely unnecessary, and the heating tube can be directly welded and fixed to both ends of the heating tube. This allows
The airtightness in the reactor main body is reliably maintained for a long time, and the structure of the dry distillation pyrolysis reactor main body can be simplified, the weight can be reduced, and the assembly workability can be improved. In addition to making it possible to reduce the cost, the frequency of failures is reduced and the repair cost can be reduced. Further, the thermal expansion of the entire reactor body can be easily absorbed in the heated gas outlet casing and the heated gas inlet casing by the same method as in the related art, and the reactor body 1 is caused by the thermal expansion. Almost no problems.

In the present invention, the outer surface of the heating tube forming the body is kept warm by a heat insulating material or the like, and cannot function as a heat transfer surface for waste. Even so, the space between the inner wall surface of the body and the heating tube is in a state where the pyrolysis products are fixed, and the outer surface of the heating tube does not substantially function as a heat transfer surface. As a result, the reactor body of the present invention is not inferior to the conventional reactor body in terms of heat transfer from the heating gas passing through the heating pipe to the waste. Since the tubes are connected by welding via flat fins, the fins greatly contribute to the heat transfer, and the number of heating tubes can be reduced as compared with the conventional reactor body. The space for pyrolysis of waste will be expanded.

Further, in the present invention, since the cylindrical body itself is formed by the heating tube and the fin, the heating tube is provided near the inner wall surface of the steel body like the conventional reactor body. Even without disposing, the waste in the main body can be heated evenly. As a result, the gap between the inner peripheral surface of the body and the heating pipe becomes a so-called blind spot as in the case of the conventional reactor main body, and there is no such thing that waste is contained therein and carbonized, and the inside of the main body is eliminated. The pyrolysis space is always kept clean.

As described above, the present invention has excellent practical effects in terms of simplification of the structure of the reactor main body and securing of the airtightness of the pyrolysis pyrolysis space.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a waste carbonization pyrolysis reactor according to the present invention.

FIG. 2 is a schematic enlarged cross-sectional view taken along the line II in FIG.

FIG. 3 is a partially enlarged cross-sectional view of a portion P in FIG. 1;

FIG. 4 is an explanatory view of a waste carbonization pyrolysis melting and burning treatment plant using the waste carbonization pyrolysis reactor according to the present invention.

FIG. 5 is an explanatory diagram of a heating gas system of a waste carbonization pyrolysis reactor.

FIG. 6 is a schematic sectional view of a reactor body of a conventional waste carbonization pyrolysis reactor.

FIG. 7 is a sectional view taken along the roll of FIG. 6;

8 is a partially enlarged view of a portion Q in FIG. 6;

FIG. 9 is a partially enlarged view of a portion R in FIG. 6;

[Explanation of symbols]

A is a substance to be carbonized (waste), B is a carbonized gas, C is a pyrolysis residue, G is a heated gas, 1 is a reactor body, 2 is a heated gas inlet, 2a is an inlet casing, 3 is a heated gas outlet, 3a Is an outlet casing, 4 is a waste supply port, 5 is a pyrolysis product outlet, 7 is a heating tube, 7a is a fin, 8 is a tube plate, 8a is a support plate, 10 is a refuse supply feeder, and 11 is a reactor main body support. Table, 12 is a supporting roller, 13 is a rotary drive device, 14 is a gear, 15 is a separation / conveyance device, 16 is a carbonization gas outlet,
Is a carbonization residue outlet, 18 is a support base, 19 is a cylindrical body, 20 is a shelf-shaped protruding portion, 21 is a head plate, 22 is a short cylinder, 23 is a space, 24 is a reinforcing ring, 25 Is a reinforcing ring, 26 is a reinforcing ring, 27 is a coarse grain, 28 is a fine grain, 29 is a slag, 30 is a water-cooled slag, 31 is a waste pit, 32 is a rotary shletter, 33 is a crane,
34 is a sewage sludge tank, 35 is a hopper, 36 is a loop pipe, 36a is a bypass pipe, 37 is a blower, 38 is a heat exchanger, 39 is a burner heater, 40 is a melting and burning device,
41 is a vibration conveyor, 42 is a separator, 43 is a roller crusher, 44 is a silo, 45 is a gas cooling room, 46 is a waste heat boiler, 47 is a power generation facility, 48 is a dust collector, 49 is a treatment of an activated carbon adsorption tower, etc. The apparatus, 50 is a chimney, 51 is an air preheater, 52 is piping, and 53 is piping.

Claims (2)

[Claims] In a waste pyrolysis reactor for waste, wherein a heating gas is circulated through a heating pipe and heat of the heating gas heats a material to be dry-distilled in the reactor body, the reactor body is Characterized in that the reactor is formed into a cylindrical shape from a plurality of heating tubes arranged in parallel and fins connecting adjacent heating tubes to each other. 2. The dry distillation pyrolysis reactor for waste according to claim 1, wherein both ends of the heating tube and the fin are air-tightly supported and fixed by welding to a tube plate closing both sides of the reactor body. .