JP6690873B2 - Rotary kiln - Google Patents

Description

  The present invention relates to a rotary kiln used for incineration / firing of various kinds of objects to be treated, and more particularly to a rotary kiln having a refractory lined inside a kiln body.

  Conventionally, for example, when a combustible waste such as waste wood finely crushed is incinerated or an inorganic material such as powdered gypsum is fired, a rotary kiln, for example, may be used. This type of rotary kiln protects the kiln body from the high temperatures associated with incineration / baking of the object to be treated by lining the inner peripheral wall of the cylindrical steel plate that constitutes the kiln body with refractory materials such as refractory bricks and refractory mortar. I am trying to do it.

  By the way, when the surface of the refractory material lined on the inner peripheral wall of the steel plate of the kiln body is formed to be smooth, the object to be treated supplied into the kiln body is not agitated so much that the furnace is used in the bottom layer portion of the object to be treated. There is a possibility that it may flow down without being in sufficient contact with the internal air (oxygen) and be discharged. For example, in the case of combustible waste such as waste wood, insufficient oxygen will cause combustion failure and many unburned residues will occur. In addition, if an inorganic material such as gypsum is used, there is a possibility that a large amount of insufficiently fired material is generated.

  On the other hand, in Patent Document 1 (Japanese Patent Laid-Open No. 8-233234), a refractory is lined on the inner peripheral wall of a metal cylinder forming the kiln body, and a lifter made of the same refractory is provided on the inner wall of the refractory. Described is a rotary kiln for incinerating refuse which is spirally protruded, and in the case of the rotary kiln having the above-mentioned structure, it is necessary to appropriately stir the object to be processed supplied to the inside of the kiln by scraping it up with the lifter. Therefore, it is considered that the chance of contact with the air in the furnace is enhanced, and the incineration / firing process can be performed relatively evenly.

JP-A-8-233234

  However, like the above-mentioned conventional device, the lifter having a substantially convex cross section provided so as to project from the inner wall surface of the refractory material lined in the kiln body has a load or shearing force applied to the lifter portion each time the workpiece is scraped. As a result of repeated loads such as, etc., it may be possible that wear, cracks, defects, etc. may occur in the lifter part and the refractory around it even if the operation time is relatively short, and the stirring function may deteriorate early. It

  In view of the above points, the present invention is a rotary kiln in which a refractory is lined in the kiln body, while devising the structure of the inner wall surface of the refractory to prevent the occurrence of early wear, cracks, defects, etc. An object of the present invention is to provide a rotary kiln that can appropriately stir the material to be treated supplied therein and increase the chance of contact with the air in the furnace and can perform incineration / firing treatment with less unevenness.

In order to solve the above-mentioned problems, in a rotary kiln according to claim 1 of the present invention, a kiln body having a refractory lined inside a cylindrical steel plate is rotatably supported in an inclined manner, and one end of the kiln body is rotatably supported. A rotary kiln having a burner for supplying hot air to the refractory, wherein laterally long rectangular concave portions composed of a long side portion and a short side portion with respect to the inner wall surface of the refractory are provided at predetermined intervals in the kiln circumferential direction and the longitudinal direction. A plurality of the rectangular recesses are formed so that the rectangular recesses are wide and have a shallow bottom structure, and an area of the rectangular recesses occupies most of the inner wall surface of the refractory with an interval in the circumferential direction shorter than the width of the rectangular recesses. In addition, the long side of the rectangular recess on the side that rises when the kiln body is rotated is carved so as to be inclined in a direction opposite to the tilt direction of the kiln body, and the object to be processed in the rectangular recess is processed. I carry things around Said dropped along the slope of the rectangular recess is an object to be processed and characterized in that a structure to return to the kiln upstream.

According to the rotary kiln of claim 1 of the present invention, a plurality of horizontally long rectangular concave portions having a long side portion and a short side portion with respect to the inner wall surface of the refractory are provided at predetermined intervals in the kiln circumferential direction and the longitudinal direction. Engraved , the rectangular recess has a wide and shallow structure, and the circumferential interval is shorter than the width of the rectangular recess so that the area of the rectangular recess occupies most of the inner wall surface of the refractory. In addition, the long side of the rectangular recess on the side that rises when the kiln body is rotated is carved so as to be inclined in a direction opposite to the inclination direction of the kiln body, and the object to be processed in the rectangular recess is While carrying around, the object to be processed is returned to the upstream side of the kiln by dropping it along the inclination of the rectangular recess, so that the object to be processed is appropriately stirred without applying too much load or shearing to the refractory. Can be processed and early refractory Wear and cracking, while enabling suppressing generation of defects such, it is possible to incineration and burning process with less unevenness is enhanced chance of contact with the object and the furnace air. In addition, since the rectangular recess has a shallow bottom structure, the object to be processed can be lifted and dropped along the inner wall surface of the refractory material and agitated, whereby an object to be processed with high scattering property can be obtained. Even in the case of incineration / baking treatment, it is possible to suppress the problem of scattering in the unburned / unbaked state, and it is possible to carry out the treatment appropriately.

Also, can more effectively stirring process the object to be treated supplied into the kiln body, it is possible to incineration and burning treatment even less elevated and uneven chance of contact with an object to be processed and furnace air.

It is a schematic explanatory drawing which shows one Example of the rotary kiln which concerns on this invention. It is an AA end view of FIG. It is a principal part enlarged view of FIG.

  In the rotary kiln according to the present invention, the inner peripheral wall of the cylindrical steel plate, for example, a kiln body lining a refractory material such as refractory bricks and refractory mortar is rotatably supported, and at one end of the kiln body. Equipped with a burner for hot air supply. Further, on the inner wall surface of the refractory, a plurality of horizontally long rectangular concave portions each having a long side portion and a short side portion are engraved at predetermined intervals in the kiln circumferential direction and the longitudinal direction, and the kiln body is rotated as the kiln body rotates. Compared to conventional lifters with a substantially convex cross-section, loads such as shear and other loads on the refractory can be carried around by dropping the workpieces that flow in the kiln body into the rectangular recesses one after another. While it is possible to suppress the occurrence of premature wear, cracks, defects, etc., it is possible to appropriately stir the object to be processed and increase the chances of contact with the air (oxygen) in the furnace, and incinerate with less unevenness. Baking process is possible.

  Further, the rectangular recess has a shallow structure with a relatively shallow depth, preferably about 10 to 20 mm, whereby the object in the rectangular recess is gradually lifted before being lifted to the upper side of the kiln body. Spilled along the inner wall surface of the refractory, for example, even if the object to be treated is fine and highly dispersible, it is unnecessarily agitated by the hot air from the burner and scatters unburned or unfired. Therefore, it is possible to prevent problems such as spillage from the kiln body, and also to reduce the amount of dust.

  In addition, the long side of the rectangular concave portion is engraved so as to be inclined in a direction opposite to the inclination direction of the kiln body, and the workpiece in the rectangular concave portion is carried around with the rotation of the kiln body while the rectangular concave portion is inclined. By dropping it along the direction of the kiln, it is returned to the upstream side of the kiln a little, so that the object to be treated can be more effectively agitated and the chance of contact with the air in the furnace can be further enhanced.

  As described above, according to the rotary kiln having the above-described configuration, the oblong wall surface of the refractory material lined in the kiln body is replaced with the conventional lifter, and a rectangular recess having a horizontally long and shallow structure is engraved. Therefore, it is possible to reduce the load on the refractory and the load such as shearing, and it is possible to suppress the occurrence of premature wear, cracks, defects, etc., which is suitable in terms of maintenance. It is possible to appropriately stir while suppressing the amount, increase the chances of contact with the air in the furnace, and incinerate and fire evenly. Also, since the structure is simple, it can be provided relatively easily and at low cost, and is easy to adopt.

  An embodiment of the present invention will be described below with reference to the drawings.

  1 in the figure is a rotary kiln used for incineration of combustible waste such as waste wood finely crushed, or for firing of inorganic materials such as powdered gypsum, A kiln body 4 having a refractory material 3 such as refractory brick or refractory mortar lined in a predetermined layer thickness on the inner peripheral wall of a cylindrical steel plate 2 is rotatably supported on a base 5 in a rotatable manner. The kiln body 4 is provided with a supply conveyor 6 for supplying an object to be processed and a burner 7 for supplying hot air, while the other end of the kiln body 4 is provided with a secondary combustion chamber 8. An exhaust duct 9 is connected to the upper end of the secondary combustion chamber 8, and incineration ash, burned material, etc. generated by incineration / baking of the object to be treated are discharged to the lower end. The discharge unit 10 is provided.

  Further, on the inner wall surface of the refractory 3 lined with the inner peripheral wall of the kiln body 4, a horizontally long rectangular concave portion composed of a pair of parallel long side portions 11a facing each other and a pair of parallel short side portions 11b facing each other. A plurality of 11 are provided at predetermined intervals in the circumferential direction and the longitudinal direction of the kiln body 4, and the workpieces flowing in the kiln body 4 as the kiln body 4 rotates are successively dropped into the rectangular recess 11. The load on the refractory 3 such as shearing and the like can be reduced compared to a lifter having a substantially convex cross-section, and the occurrence of premature wear, cracks, and defects of the refractory 3 can be suppressed. Although it is possible, it is possible to appropriately stir the object to be treated and increase the chance of contact between the object to be treated and the air (oxygen) in the furnace.

  Further, the depth of the rectangular concave portion 11 is relatively shallow, and preferably has a shallow bottom structure of about 10 to 20 mm, so that the object to be processed in the rectangular concave portion 11 can be lifted up to the upper side of the kiln body 4. Gradually spills along the inner wall surface of the refractory 3, and even if it is highly dispersible, such as waste wood that has been finely crushed or powdered gypsum, it will not be affected by the hot air from the burner 7. We are trying to prevent problems such as being incinerated and scattered as it is when not fired.

  It should be noted that the size and installation interval of the rectangular recesses 11 may be appropriately determined in consideration of the size of the kiln body 4 and the like so that they are arranged in a well-balanced manner in the furnace. If the bottom structure is adopted, the amount of objects to be carried around in the rectangular recess 11 at one time may be reduced and the agitation processing capability may be deteriorated. However, for example, if the inner peripheral diameter of the kiln body 4 is about 1900 mm. If the long side portion 11a of the rectangular concave portion 11 has a wide structure of about 1000 mm and the short side portion 11b has a length of about 400 mm, it is arranged so that about 8 to 10 pieces are provided in the circumferential direction of the kiln. In addition, it is possible to maintain the agitation processing capacity that is comparable to that of the conventional lifter without significantly reducing the amount of the object to be processed that can be carried around in the rectangular recess 11 at a time, which is more preferable. .

  Further, as shown in FIG. 3, the rectangular recess 11 is engraved so that the long side 11a thereof is inclined in a direction opposite to the inclination direction of the kiln body 4 (left direction in the drawing), and the kiln is formed. The object to be processed in the main body 4 is carried along with the rotation of the kiln and dropped along the inclination of the rectangular recess 11 so that the object to be processed is slightly returned to the upstream side of the kiln. Can be more effectively agitated while spending a certain amount of time. For example, if the rectangular recess 11 has a wide structure as described above, the agitation that accompanies the rectangular recess 11 having a shallow bottom structure can be achieved. The decrease in the processing capacity can be sufficiently compensated, and the object to be processed can be agitated to the same extent as the lifter.

  When the rectangular recess 11 is arranged in a slanted manner, the object to be processed in the rectangular recess 11 is guided to the vicinity of the corner 11c and spills out, so that clogging of the object to be processed and uneven wear of the corner 11c may occur. In order to suppress it, the corner 11c is formed in a substantially arc shape.

  Further, the inclination angle θ of the rectangular concave portion 11 may be appropriately determined so that an appropriate stirring process can be performed according to the property of the object to be processed, the supply amount, etc., but at least the repose angle of the object to be processed should be set. The object to be processed dropped in the rectangular recess 11 can be smoothly guided to the kiln upstream side along the lower long side 11a, which is preferable.

  In the rotary kiln 1 having the above-described structure, for example, when burning combustible waste such as finely crushed waste wood or firing inorganic material such as powdered gypsum, first the burner 7 is used. After burning and supplying hot air into the kiln body 4 to raise the temperature in the furnace, the supply conveyor 6 supplies the object to be processed into the furnace in predetermined amounts.

  The object to be processed supplied into the kiln body 4 flows down on the inner wall surface of the refractory 3 lined in the kiln body 4, and when the object reaches the position of the rectangular recess 11 in time, the object to be processed goes inside. It fits in like a depression and is carried around as the kiln body 4 rotates. Then, when the object to be processed in the rectangular recess 11 is lifted in the kiln rotation direction, for example, to about 1/8 to 1/4 round, it gradually spills along the inner wall surface of the refractory material 3 at that time. A part of the object to be spilled down is slightly returned to the kiln upstream side along the lower long side 11a of the inclined rectangular recess 11. Then, the object to be treated is effectively agitated while repeating a series of these operations, and is uniformly incinerated and fired while uniformly contacting with the air in the furnace.

  As described above, in the rotary kiln 1 of the present invention, the oblong wall surface of the refractory 3 lined in the kiln body 4 is provided with the oblong rectangular recess 11 having a shallow structure instead of the conventional lifter. Therefore, it is possible to reduce the load on the refractory 3 that is applied when stirring the object to be processed, such as shearing, and to suppress the occurrence of premature wear, cracks, etc., and to treat the object to the same extent as the lifter. It can be agitated and can be incinerated and fired with less unevenness. In addition, it is possible to incinerate and fire the material to be treated while appropriately stirring it without scattering it too much, for example, incinerating combustible waste such as finely crushed waste wood or powdery gypsum. The apparatus is particularly suitable for treating an object having a high scattering property such as a firing treatment of an inorganic material.

  If the object to be treated supplied to the inside of the kiln body 4 is a combustible waste material such as waste wood, for example, the latter half of the kiln has combusted to some extent and has been ashed. If the ash stays on the bottom side of the kiln body 4 without being stirred, a part of the ash is likely to be melted and clinker is likely to be generated, and in some cases, the ash may adhere to and grow on the refractory 3 surface. However, if the rectangular recess 11 is provided at least in the latter half of the kiln, the ashed waste wood can be thoroughly agitated by contacting with the air in the furnace evenly while stirring appropriately. This makes it possible to effectively prevent the occurrence of clinker, which is suitable for maintenance.

DESCRIPTION OF SYMBOLS 1 ... Rotary kiln 2 ... Steel plate 3 ... Refractory 4 ... Kiln main body 7 ... Burner 11 ... Rectangular recess 11a ... Long side part (rectangular recess) 11b ... Short side part (rectangular recess)

Claims (1)

A rotary kiln that rotatably supports a kiln body in which a refractory material is lined on an inner peripheral wall of a cylindrical steel plate, and has a burner for supplying hot air at one end of the kiln body, wherein the inner wall surface of the refractory material is a rectangular recess oblong consisting of a long side portion and the short side portion and a plurality engraved at predetermined intervals in the kiln circumferential and longitudinally against, the rectangular concave portion is wider at shallow structure, and to the circumferential direction The width of the rectangular recess is set to be shorter than the width of the rectangular recess so that the area of the rectangular recess occupies most of the inner wall surface of the refractory and the long side of the rectangular recess on the side that rises when the kiln body rotates. The part side is engraved so as to be inclined in the direction opposite to the tilt direction of the kiln body, and the object to be processed in the rectangular recess is carried around and dropped along the inclination of the rectangular recess to carry the object to the kiln upstream. a configuration in which returned to the side Rotary kiln, characterized in that.

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