JP4670861B2 - Rotary kiln - Google Patents

Description

  The present invention relates to a rotary kiln used for drying, pyrolysis, and carbonization treatment by indirectly heating organic matter such as biological resources such as waste and biomass by external heat.

  As an alternative to the combustion system in which waste is combusted in an incinerator among waste treatment systems such as municipal waste, in recent years, waste is thermally decomposed by heating in a low oxygen atmosphere, Combustible pyrolysis gas, carbide (char) and ash as pyrolysis residue are generated, the pyrolysis gas and pyrolysis residue are led to the melting furnace, and a small amount of air (for example, air ratio is about 1.3) The waste is pyrolyzed and gasified and melted in a combustion furnace, which is burned at a high temperature and taken out as molten slag, and the exhaust gas is treated with an exhaust gas treatment device and released to the atmosphere. After combustion, exhaust gas treatment is performed and then released to the atmosphere. On the other hand, the pyrolysis residue is sorted, pulverized, and the carbonization of waste is recovered (pyrolysis gasification equipment) Developed) , It has been put to practical use.

  An external heat type rotary kiln has been used as one of apparatuses for performing thermal decomposition and carbonization of wastes in this type of waste pyrolysis gasification melting equipment and waste carbonization equipment. .

  FIG. 3 shows an outline of an example of a conventionally proposed external heating type rotary kiln. A supply pipe 2a is integrally connected to the inlet 2 side of one end, and a discharge pipe 3a is integrally connected to the outlet 3 side of the other end. A heating channel 6 is formed between the connected inner cylinder 4 and the outer cylinder 5 arranged concentrically outside the inner cylinder 4 so that the outer cylinder 5 and the inner cylinder 4 can be rotated together. The kiln main body 1 having a double cylinder structure is configured, and the kiln main body 1 is rotated while being kept horizontal or inclined so that the outlet 3 side at the other end is slightly lower than the inlet 2 side at one end. Place it sideways as possible.

  A dust feeder 7 is provided at the inlet 2 of the kiln main body 1 so as to be inserted inside the supply pipe 2 a, and the waste 9 thrown into the charging hopper 8 is supplied to the inlet 2 by the dust feeder 7. It is like that. On the other hand, the outlet 3 of the kiln main body 1 is provided with a separation chamber 12 for separating the pyrolysis gas 10 and the pyrolysis residue 11 from the top of the separation chamber 12 and the above-mentioned pyrolysis gas 10 from the bottom. Each of the thermal decomposition residues 11 can be taken out.

Further, a heating gas inlet 13 communicating with the heating channel 6 is provided on the outlet 3 side of the kiln main body 1, and a heating gas communicating with the heating gas channel 6 is provided on the inlet 2 side of the kiln main body 1. Each gas outlet 14 is provided so that hot air 15 as a heating gas supplied from the heating gas inlet 13 can be discharged from the heating gas outlet 14 after flowing through the heating channel 6.
Thereby, in the state where the kiln main body 1 is rotated at a low speed (for example, 1 rpm), the waste 9 in the charging hopper 8 is gradually supplied into the inner cylinder 4 of the kiln main body 1 by the feeder 7. By supplying the hot hot air 15 from the heated gas inlet 13 to the heating flow path 6 and circulating it, the waste 9 in the inner cylinder 4 is indirectly heated by the external heat from the hot air 15 and is thermally decomposed. Carbonized.

  By the way, the rotary kiln having the above configuration is an indirect heating system in which only the peripheral surface of the inner cylinder 4 is a heat transfer surface. Therefore, in order to increase the processing capacity, the diameter of the inner cylinder 4 is increased or the inner cylinder 4 is The length of the rotary kiln will increase.

  Therefore, in the indirect heating type rotary kiln by external heat, in order to increase the heat transfer area and increase the processing capacity without increasing the overall size, as shown in FIG. A plurality of plate-like heat transfer tubes 16 in which gas passages 17 are formed in a flat rectangular cross-sectional shape inside the inner circumferential surface at required intervals in the circumferential direction are arranged in the rotational direction of the inner cylinder 4 (arrow r direction). Are installed in a spiral shape over the entire length in the longitudinal direction so as to project the required dimension to the inside of the inner cylinder 4 at an angle inclined forward, and heated from the heated gas inlet 13 into the gas passage 17 of each heat transfer tube 16. Conventionally, it has been proposed that a part of the hot air 15 (see FIG. 3) supplied to the flow path 6 be circulated (see, for example, Patent Document 1).

JP 2002-156105 A

  However, according to the rotary kiln of the type in which the spiral heat transfer tube 16 is provided in the inner cylinder 4 as shown in FIG. 4, each spiral heat transfer tube 16 is sequentially discarded as the inner cylinder 4 rotates. Since the objects 9 are scooped up, the entire rotary kiln can be brought into contact with the waste 9 by using both side surfaces of the spiral heat transfer tubes 16 as heat transfer surfaces in addition to the peripheral surface of the inner cylinder 4. Although it is effective to increase the heat transfer area and increase the processing capacity without increasing the size, it is necessary to manufacture the heat transfer tube 16 having the flat cross-sectional shape and the gas passage 17 inside in a spiral shape. For this reason, it is the actual situation that labor and manufacturing cost increase to manufacture the spiral heat transfer tube 16 with high accuracy.

  Furthermore, when a rotary kiln is installed, the kiln main body 1 can usually be transported as a unit up to a certain scale. However, for example, due to restrictions on loading of a transport vehicle, a certain scale, for example, the length may exceed about 15 m. The scaled-up kiln main body 1 needs to be manufactured in a factory with the kiln main body 1 divided in the length direction, and it is necessary to perform on-site assembly in the length direction using the division body manufactured in the factory. When the on-site assembly in the longitudinal direction of the kiln body 1 is performed by a rotary kiln of the type having the spiral heat transfer tube 16, the inner cylinder 4 is arranged in accordance with the division of the kiln body 1 in the longitudinal direction. Each spiral heat transfer tube 16 attached to the peripheral surface must be manufactured in the factory in a state of being divided in the length direction, and it is necessary to assemble on site. However, the local assembly of each spiral heat transfer tube 16 is also complicated and accurate. Since it is required, the manufacturing cost increases.

  Further, when the heat transfer tubes 16 are provided on the inner peripheral surface of the inner cylinder 4 so as to be inclined forward in the rotation direction (arrow r direction) of the inner cylinder 4, the heat transfer tubes 16 are forward in the kiln rotation direction. Since an acute corner portion is formed between the surface facing the inner surface and the inner peripheral surface of the inner cylinder 4, the waste corner 12 and the pyrolysis residue 11 (see FIG. 3) are clogged and retained in the acute corner portion. There is also a concern that it may be easy to do.

  Therefore, in the rotary kiln of the indirect heating method by external heat, the present invention can reduce the labor required to manufacture what can increase the heat transfer area and increase the processing capacity without increasing the overall size, The purpose is to provide a rotary kiln capable of reducing the production cost.

In order to solve the above-mentioned problems, the present invention provides a kiln main body comprising a heating flow path between an inner cylinder having both ends in the longitudinal direction connected to a supply pipe and a discharge pipe, and an outer cylinder provided outside the inner cylinder. In the state where the inner cylinder is rotated, the raw material supplied into the inner cylinder from the supply pipe is indirectly heated by the external heat of the high-temperature gas flowing through the heating flow path, and then dried, pyrolyzed, circumferentially predetermined spacing position of the inner circumferential surface of the inner cylinder in are also available carbonization a rotary kiln, the lifter having a hollow structure extending parallel to the axial direction over the entire length of the inner cylinder, the circumferential direction of the lifter high Rutotomoni, with the high dimension provided by projecting inward so as to be higher required dimension than the height of the height dimension of the plurality of lifters inner cylinder peripheral surface of the predetermined number every other lifter Lifter tip and lifter with low height Of these, a bent portion that is bent to the front in the direction of rotation of the inner cylinder is provided at the tip of the lifter of the height that is lower than the lifter having a height that is higher than the one that is adjacent to the rear in the direction of rotation of the inner cylinder. In addition, the inside of the lifter is used as an internal heating flow path, and a part of the high-temperature gas flowing through the heating flow path can be circulated.

According to the rotary kiln of the present invention, the following excellent effects are exhibited.
(1) A kiln body provided with a heating flow path between an inner cylinder having both ends in the longitudinal direction connected to a supply pipe and a discharge pipe and an outer cylinder provided outside thereof is provided, and the inner cylinder is rotated. In a rotary kiln that allows the raw material supplied into the inner cylinder from the supply pipe to be dried, pyrolyzed and carbonized by indirect heating with the external heat of the high-temperature gas flowing through the heating flow path A lifter having a hollow structure extending parallel to the axial direction over the entire length of the inner cylinder is disposed at a circumferentially required interval position on the inner circumferential surface of the inner cylinder, and a plurality of lifters of the required number in the circumferential direction among the lifters are provided. Protruding inward so that the height dimension from the inner peripheral surface of the inner cylinder is higher than the height dimension of the other lifters, and the tip of the lifter with the high height dimension, Among the lower lifters, the lifter with the above height dimension is high. In addition, a bent portion bent at a required angle forward in the inner cylinder rotation direction is provided at the tip of the lifter having a low height excluding those adjacent to the rear in the inner cylinder rotation direction. Since the inside is an internal heating flow path and a part of the high-temperature gas flowing through the heating flow path can be circulated, the structure of each lifter can be simplified, Each lifter can be easily and accurately manufactured. Therefore, the kiln body provided with each lifter can have a simple structure that can be easily assembled and manufactured, and can reduce the manufacturing effort and the manufacturing cost.
(2) In addition to the structure that allows easy assembly and production of the kiln main body as described above, in addition to the peripheral surface of the inner cylinder, heat transfer for indirectly heating the surface of each lifter Therefore, the heat transfer area can be increased and the processing capacity can be increased without increasing the size of the entire rotary kiln.
(3) Furthermore, when the kiln main body is scaled up, the kiln main body is assembled on site from the lengthwise division of the kiln main body manufactured at the factory, and then the above-described simple structure is provided on the inner peripheral surface of the inner cylinder. Since it is only necessary to attach each lifter, both the factory production and the field assembly work can be facilitated, and the process of the field installation work can be expected to be shortened.
(4) Furthermore, among the lifters arranged in the circumferential direction of the inner peripheral surface of the inner cylinder, a plurality of lifters for every required number in the circumferential direction are used, and the height dimension from the inner peripheral surface of the inner cylinder is another lifter. Since the required dimensions are higher than the height dimensions of the steel sheet, the heat transfer area for indirect heating of the raw material should be increased compared to the case where lifters having the same height dimensions are provided in the circumferential direction. It is possible to further improve the processing capability of the rotary kiln.
(5) In addition, the height of the lifter except for the tip of the lifter with a high height and the lifter with a low height that is adjacent to the rear of the lifter with a high height in the inner cylinder rotation direction. Since the lower end of the lifter is configured to have a bent portion bent at a required angle forward in the direction of rotation of the inner cylinder, each lifter provided with the bent portion at the time of rotation of the inner cylinder raises the raw material Therefore, it is possible to extend the contact time with the scooped raw material, so that heat transfer to the raw material can be promoted, and further improvement in the processing capacity of the rotary kiln can be expected. In addition, the height of the lifter having such a height dimension that is a concern when a bent portion bent forward in the inner cylinder rotation direction is provided at the tip of the lifter adjacent to the rear in the inner cylinder rotation direction of the lifter having a high height dimension. It is possible to eliminate the possibility that the tip of the lifter adjacent to the rear in the direction of rotation of the inner cylinder of the high lifter approaches the lifter having a high height and clogging due to the material being caught in the portion.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

Figure 1 (a) (b) shows an embodiment of Russia Tarikirun, in a rotary kiln with a similar structure as shown in FIG. 3, the circumferential predetermined spacing position of the inner circumferential surface of the inner cylinder 4, for example, the circumferential direction The lifters 18 and 19 having a hollow structure having a flat rectangular cross-section at intervals of 30 degrees and extending in parallel to the axial direction (furnace length direction) over the entire length of the inner cylinder are connected to the inner circumference of the inner cylinder 4. It is provided so as to project inward at a right angle or near a right angle with respect to the tangential direction of the surface.

  The internal space of each of the lifters 18 and 19 has two locations, one end in the longitudinal direction near the heated gas inlet 13 and the other end in the longitudinal direction near the pyrolysis gas outlet 14 of the lifters 18 and 19. The configuration is such that the heating channel 6 is communicated with through holes (not shown) drilled in corresponding portions of the cylinder 4. Thus, the interior of each of the lifters 18 and 19 serves as an internal heating channel 20 through which a part of the hot air 15 supplied from the heating gas inlet 13 to the heating channel 6 is circulated.

  Further, among the lifters 18 and 19 arranged in the circumferential direction, a plurality of lifters 18 at every required number in the circumferential direction, for example, four lifters 18 arranged at intervals of 90 degrees in the circumferential direction are provided on the inner cylinder 4. The height dimension a from the inner peripheral surface is set to be higher than the height dimension b of the other lifters 19. Specifically, the height dimension a of each lifter 18 having a high height is set to about twice the height dimension b of each lifter 19 having a low height. Note that there is at least an interval several times the maximum particle size of the waste 9 as a raw material for pyrolysis and carbonization treatment between the tip portions (inner end portions) of the lifters 18 having a high height. In this way, it is possible to prevent the possibility of clogging the waste 9 between the tip portions (inner end portions) of the lifters 18 having a high height.

  An arrow r in FIG. 1B indicates the direction of rotation of the inner cylinder 4. In FIG. 1B, the description of the waste 9 is omitted. Other configurations are the same as those shown in FIG. 3, and the same components are denoted by the same reference numerals.

  In the case of using the rotary kiln having the above-described configuration, when hot hot air 15 is supplied from the heating gas inlet 13 to the heating flow path as in the case shown in FIG. While flowing through the formed heating flow path 6 toward the heating gas outlet 14, a part of the flow is passed through the internal heating flow paths 20 of the lifters 18 and 19. In this state, while the kiln main body 1 is rotationally driven at a low speed (for example, 1 rpm) in the direction indicated by the arrow r in FIG. If the supplied waste 9 passes through the inner cylinder 4 from the inlet 2 side to the outlet 3 side, each lifter that rotates together with the inner cylinder 4 is gradually supplied. 18 and 19, and the waste 9 is mixed with the heating passages 6 and 6 with the peripheral surface of the inner cylinder 4 and both side surfaces of the lifters 18 and 19 as heat transfer surfaces. Indirect heating is performed by the heat from the hot air 15 flowing through the air 20, and drying, pyrolysis, and carbonization are performed.

Thus, according to the rotary kiln having the above-described configuration , each of the lifters 18 and 19 has a shape extending in parallel with the axial direction of the inner cylinder 4, that is, a shape extending straight. Both the side surfaces and the front end surface (inner end surface) can be flat. Thereby, the structure of each lifter 18 and 19 can be made simple, and it becomes possible to manufacture each lifter 18 and 19 easily and accurately. Therefore, the kiln main body 1 including the lifters 18 and 19 can have a simple structure that can be easily assembled and manufactured, and can reduce manufacturing effort and manufacturing cost. .

  In addition to the structure that is easy to assemble and manufacture as described above, in addition to the peripheral surface of the inner cylinder 4, the surfaces of the lifters 18 and 19 are indirectly heated with the waste 9 as a raw material. Therefore, in the rotary kiln of the indirect heating method by external heat, it is possible to increase the heat transfer area and increase the processing capacity without increasing the overall size. Therefore, when it is desired to have a processing capacity comparable to that of a conventional rotary kiln in which only the peripheral surface of the inner cylinder 4 as shown in FIG. 3 is used as a heat transfer surface, the entire rotary kiln can be reduced in size.

Furthermore, when the rotary kiln having the above-described configuration is scaled up, after the large-scale kiln body 1 is locally assembled from the longitudinally divided body of the kiln body 1 manufactured at the factory, Since the lifters 18 and 19 having a simple structure may be attached while assembling in the length direction as appropriate, both the factory production and the field assembly can be facilitated. This can be expected to shorten the process of local installation work.

  Further, among the lifters 18 and 19, a plurality of lifters 18 of every required number in the circumferential direction have a high height dimension from the inner peripheral surface of the inner cylinder 4 within a range where clogging due to the waste 9 is not caught. As a result, the heat transfer area for indirect heating of the waste 9 can be increased compared to the case where all the lifters having the same height are provided in the circumferential direction, and the processing capacity of the rotary kiln can be increased. Can be improved.

  Moreover, the lifters 18 and 19 are provided so as to protrude inward at a right angle or an angle close to a right angle with respect to the tangential direction of the inner peripheral surface of the inner cylinder 4. Since an acute corner portion is not formed between the front surface of the inner cylinder 4 in the rotational direction (arrow r direction) and the inner peripheral surface of the inner cylinder 4, the inner cylinder 4 in each of the lifters 18, 19 is not formed. It is possible to prevent the waste 4 and the pyrolysis residue 11 from clogging and staying between the surface facing forward in the rotation direction and the inner peripheral surface of the inner cylinder 4. Therefore, improvement of the processing capability of the rotary kiln can also be expected from this.

Next, FIG. 2 shows an embodiment of the rotary kiln of the present invention, in the same configuration as shown in FIGS. 1 (A) and (B), at the tip of the lifter 18 having a high height a, in the direction of rotation of the inner cylinder. A bent portion 18a bent at a required angle in the forward direction (in the direction of arrow r) is provided, and among the lifters 19 having a low height dimension b, the inner cylinder rotation direction (in the arrow r direction) of the lifter 18 having a high height dimension a. A bent portion 19a that is bent at a required angle forward in the direction of rotation of the inner cylinder (in the direction of arrow r) is provided at the tip of the lifter 19 having a low height dimension b other than those adjacent to the rear.

  In FIG. 2, the description of the waste 9 is omitted. Other configurations are the same as those shown in FIGS. 1A and 1B, and the same components are denoted by the same reference numerals.

  According to the present embodiment, when the inner cylinder 4 rotates, the inner cylinder rotation direction of the lifter 18 having the high height dimension a among the lifter 18 having the high height dimension and the lifter 19 having the low height dimension. In the lifter 19 having a low height dimension b other than the one adjacent to the rear in the direction of arrow r, the bent-up portions 18a and 19a provided at the respective tip portions suppress the fall of the waste 9 that has been scooped up. Since the contact time with the scooped waste 9 can be extended, heat transfer to the waste 9 can be promoted, and further improvement of the processing capability of the rotary kiln can be expected.

  Of the lifters 19 having a low height dimension b, the inner cylinder rotating direction (arrow r) is attached to the tip of the lifter 19 adjacent to the rear of the lifter 18 having a high height dimension a in the inner cylinder rotating direction (arrow r direction). In the case of providing a bent portion bent forward in the direction), the tip of the lifter 19 adjacent to the rear in the inner cylinder rotation direction (arrow r direction) of the lifter 18 having a high height dimension a is the height dimension described above. Since the lifter 18 approaches the lifter 18 having a high value, there is a concern that the portion may be clogged with the waste 9 being caught. However, in the rotary kiln of the present embodiment, the lifter 18 having a high height dimension a The clogging of the waste 9 as described above occurs between the tip of the lifter 19 having a low height dimension b adjacent to the rear of the inner cylinder rotation direction (arrow r direction) and the lifter 18 having a high height dimension a. The fear can be eliminated.

In addition, this invention is not limited only to the said embodiment,
The inner surface of the inner cylinder 4 and the surfaces of the lifters 18 and 19 may be corrugated or corrugated. In this way, the heat transfer area can be further expanded.

  It can also be applied to a rotary kiln that performs drying, pyrolysis, and carbonization of raw materials other than the waste 9.

  The total number of lifters 18 and 19 provided on the inner peripheral surface of the inner cylinder 4 and the ratio of the number of lifters 18 having a high height a to the number of lifters 19 having a low height are as follows: You may change suitably according to the heat-transfer efficiency etc. which are desired for a rotary kiln. Also, the ratio of the height dimension of each of the lifters 18 and 19 and the height dimension of the lifter 18 having a high height dimension a and the lifter 19 having a low height dimension is the size of the diameter of the inner cylinder 4 or is dry. Depending on the particle size and properties of the raw material to be subjected to thermal decomposition and carbonization treatment, it may be appropriately changed.

  Any type of rotary kiln may be used as long as it has a rotating inner cylinder 4 for receiving waste 9 supplied from the supply pipe 2a and performing drying, pyrolysis, and carbonization of the raw material by external heat. . Of course, various changes can be made without departing from the scope of the present invention.

Shows one form of the B Tarikirun, (b) is partially cut-schematic side view, an A-A direction arrow enlarged view of (b) is (b). Shows one embodiment of a rotary kiln of the present invention, is a view corresponding to FIG. 1 (b). It is a cutting | disconnection side view which shows the outline of an example of the rotary kiln proposed conventionally. It is a cutaway view of a kiln body showing a rotary kiln of a type having a spiral heat transfer tube in a conventionally proposed inner cylinder.

Explanation of symbols

1 Kiln Main Body 2a Supply Pipe 3a Discharge Pipe 4 Inner Cylinder 5 Outer Cylinder 6 Heating Channel 9 Waste (Raw Material)
15 Hot air (hot gas)
18 Lifter 18a Bent part 19 Lifter 19a Bent part 20 Internal heating flow path

Claims (1)

  A state in which a kiln main body having a heating flow path is provided between an inner cylinder in which both end portions in the longitudinal direction are connected to a supply pipe and a discharge pipe and an outer cylinder provided outside thereof, and the inner cylinder is rotated. In the rotary kiln, the raw material supplied into the inner cylinder from the supply pipe can be indirectly heated by the external heat of the high-temperature gas flowing through the heating flow path to be dried, pyrolyzed, and carbonized. A lifter having a hollow structure extending parallel to the axial direction over the entire length of the inner cylinder is disposed at a required circumferential position on the inner circumferential surface of the inner circumferential surface, and a plurality of lifters of the required number in the circumferential direction are included in the inner cylinder. Protruding inward so that the height dimension from the peripheral surface is higher than the height dimension of other lifters, and the tip of the lifter with the high height dimension and the lifter with the low height dimension are provided. Of these, for lifters with high height In addition, a bent portion that is bent at a required angle forward to the front in the inner cylinder rotation direction is provided at the tip of the lifter having a low height excluding those adjacent to the rear in the inner cylinder rotation direction. A rotary kiln having a configuration in which a part of a high-temperature gas that circulates through the heating channel can be circulated as an internal heating channel.

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