JPH11147737A - Preheating apparatus for sintering process of cement plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized compact preheating apparatus effective for promoting the dispersion of raw material passing through preheaters to improve the heat-exchange efficiency between the raw material with a heating gas in the preheater and enabling sufficient preheating of the raw material with a short particle path. SOLUTION: This preheating apparatus for the sintering process of cement contains preheaters 8 for heating a raw material with a hot gas and connected in multi-stages through connection pipes 25. The flow path in the connection pipe 25 has an accelerating and decelerating path structure composed of expanded flow paths 29a having large flow area and constricted flow paths 29b having small flow area. The expanded paths and the constricted paths are alternately connected with each other along the longitudinal direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preheating apparatus in which a preheater for heating a raw material by a high-temperature gas is connected in a plurality of stages by a connecting pipe in a cement plant sintering process. Regarding the structure.

[0002]

2. Description of the Related Art FIG. 7 is a system diagram showing a cement production process in a cement plant. Generally, the manufacturing process of such a cement plant includes three steps: a raw material step I, a firing step II, and a finishing step III.

In the raw material process I, a limestone yard 1,
Alternatively, raw materials from clay, silica, and iron oxide yard 2
After being pulverized by the pulverizer 3, the pulverizer is dried by the drier 4, and the components of the raw materials are prepared by the blender 5. The mixed raw materials are collected in a mill 6, further finely pulverized, sent to a raw material silo 7, and stored therein.

[0004] The firing step II is a step of firing the pulverized raw material sent from the raw material step I, and 8 is a multi-stage preheater comprising a multi-stage cyclone for preheating the raw material 22 sent from the raw material silo 7. The preheaters 8 are connected by a connecting pipe 25, and the gas in the preheaters 8 is sucked by a blower 9 and discharged to the outside from a chimney 11 via a dust collector 10 for collecting fine particles. The preheated raw material 22
Is calcined in a calciner 12 equipped with a burner 12 ', and then the raw material is calcined by a kiln 13 equipped with a burner 14'.
After being pulverized by the pulverizer 31, it is sent to a finishing step via a cooler 14 for cooling. In the firing step II, equipment such as a heavy oil facility 15 for feeding fuel to the calciner burner 12 'and the kiln burner 14' and a lime facility 16 are provided.

In the firing step II, the raw material silo 7
Raw material 22 is carried into the high-stage side of the preheater 8 composed of a multi-stage cyclone, and the high temperature (300 to 9)
(00 ° C.). Next, the calciner 12
Then, using the heavy oil sent from the heavy oil facility 15 or the coal sent from the coal facility 16 as a fuel, the raw material 22 is calcined by the burner 12 ′ and carried to the kiln 13. In the kiln 13, the raw material 22 has a maximum temperature of about 140.
Baking is performed at 0 ° C. to produce the clinker 23 (particle diameter: about 10 mm). Further, the clinker 23 is pulverized into small particles by a pulverizer 31 and transported to the cooler 14, where the cooler 14
Is cooled to almost room temperature.

In the finishing step III, the firing step
Clinker cyclone 17 for storing clinker 23 produced in II, clinker 23 from said cyclone 17
, A gypsum silo 17 ′ in which gypsum is stored, and a gypsum sent from the gypsum silo 17 ′ are dried in the drier 18 ′, and the clinker from the drier 18 for the clinker 23 is dried. Mix to a particle size of about 30μm
A mill 19 for pulverizing the cement into small particles and a cement silo 20 for storing cement delivered from the mill 19 are provided to produce fine cement from the clinker.
Reference numeral 21 denotes a cement carrier.

FIG. 8 shows an example of a conventional preheating device 8 and a connecting pipe 25 connecting the preheating device 8 in the firing step II. FIG. 9 is a view on arrow Z in FIG. 8 and 9, reference numeral 8 denotes a preheater made up of a cyclone 24, reference numeral 26 denotes a cyclone inner cylindrical portion which constitutes a distal end of a connecting pipe 25, and reference numeral 27 denotes an SP damper provided at a lower portion of the cyclone 24 for opening and closing a cyclone lower part. , 32 are weights for the SP damper 27. Numeral 24 'is an upper cyclone, 25' is a chute portion provided below the upper cyclone 24 ', 27' is a SP damper for opening and closing the lower part of the upper cyclone, and 32 'is a weight for the damper 27'.

In the preheater 8, the raw material 22 having a relatively large particle diameter collected by the upper cyclone 24 'is S
It is deposited on the P damper 27 '. When the weight of the raw material deposited on the damper 27 'becomes equal to or greater than the weight of the weight 32, the SP damper 27' is opened, and the deposited raw material 22 is removed from the SP damper 2 '.
Pass between 7 '. And this raw material 22 is connected to the connecting pipe 2
5 is dispersed and mixed with the high-temperature gas 28 flowing from the lower portion, and is transferred into the cyclone 24 while performing heat exchange with the high-temperature gas 28. In the cyclone 24, the raw material 22 having relatively large particles is subjected to a large centrifugal force and is pushed to the inner wall surface of the cyclone 24, and then is collected by an SP damper 27 provided below the cyclone 24. . On the other hand, the raw material having a relatively small particle size gathers inside the cyclone 24 and turns while passing through the cyclone inner cylindrical portion 26 to form the upper connecting pipe 2.
5 through the upper cyclone 24 '.

Although FIGS. 8 and 9 show a case where the preheater 8 has a single stage, the preheater 8 is usually provided in four to five stages and has a height of about 50 m as described above. .

[0010]

However, there are the following problems in the conventional preheater and the connecting pipe structure for connecting the preheater as shown in FIGS.

As described above, the raw material 22 having a relatively large particle diameter collected by the upper cyclone 24 'is supplied to the SP damper section 2
Deposit on 7 '. However, the SP damper part 27 'is balanced by the weight of the raw material 22 and the weight of the SP damper weight 32'. Therefore, the raw material 2 of the SP damper 27 '
2 is deposited so as to be equal to or more than the weight of the weight 32 ', S
The P damper 27 'is opened, and the deposited raw material 22 becomes S
It passes between the P dampers 27 'and is carried into the chute 25'. In such a conventional technique, the open / close type damper 27 'using a weight as shown in the figure is used. Then, the flow of the raw material 22 becomes a discontinuous powder flow, and after being passed through the SP damper 27 ′, is carried into the connecting pipe 25 via the chute 25 ′.

The powder flow of the raw material 22 into which the lumps are mixed enters the connecting pipe 25 through the chute portion 25 ', and is preheated by exchanging heat with the high-temperature gas 28 flowing into the connecting pipe 25 from below. However, in such a conventional technique, there is a problem that the heat is not efficiently exchanged due to the inclusion of the lumps as described above, and the thermal efficiency of preheating the raw material 22 is reduced. Further, it has been necessary to lengthen the path of the raw material particles in the preheater 8, and this has caused a problem that the height of the preheater 8 is significantly increased.

In view of the problems of the prior art, the present invention promotes the dispersion of the raw material passing through the preheater, improves the heat exchange efficiency with the heating gas in the preheater, and reduces the efficiency of the short particle path. Therefore, it is an object of the present invention to provide a small and compact preheater that enables sufficient preheating of raw materials.

[0014]

According to a first aspect of the present invention, there is provided a sintering process in which a preheater for heating a raw material by a high-temperature gas is connected in a plurality of stages by a connecting pipe. In the cement plant, the connecting pipe has an internal flow path configured as an acceleration / deceleration flow path in which an enlarged flow path having a large flow area and a reduced flow path having a small flow area are alternately combined along the longitudinal direction. A preheating device for a cement plant characterized by being performed is proposed.

According to a second aspect of the present invention, in addition to the first aspect, the accelerating / decelerating flow path is provided with the enlarged flow path and the reduced flow path in a tubular flow path forming member inserted inside the connecting pipe. It is formed by being alternately combined.

According to this invention, since the acceleration / deceleration flow path in which the expansion flow path and the reduction flow path are alternately combined in the connection pipe is formed, the flow of the raw material in the connection pipe is reduced in the expansion flow path. In the reduced flow path, the flow becomes an accelerated flow, and by repeating this, the turbulence of the flow becomes large.

[0017] Therefore, the dispersion of the particles of the raw material in the connecting pipe is promoted, and even if there is a lump in the raw material, this is easily dispersed and the heat exchange between the raw material and the high-temperature gas is efficiently performed. That is, the heat exchange length between the raw material and the high-temperature gas in the preheater is shortened, and the number of stages of the preheater can be reduced.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only.

FIG. 1 is a cross-sectional view of a main part of a preheating device including a preheater for a cement plant, a connecting pipe and the like according to a first embodiment of the present invention, and FIG. 2 is a view taken in the direction of arrow A in FIG.

This preheating apparatus is used in the firing step II of the cement production process shown in FIG. 7, and the outline of the firing apparatus II will be briefly described again with reference to FIG.
The raw material 22 from the raw silo 7 is carried into the high-stage side of the multi-stage preheater 8, and the high-temperature (300 to 900)
C) gas. Next, in the calciner 12, using the heavy oil sent from the heavy oil facility 15 or the coal sent from the coal facility 16 as a fuel, the raw material 22 is calcined by the burner 12 ′ and transported to the kiln 13. . In the kiln 13, the raw material 22 has a maximum temperature of about 1400 ° C.
To produce a clinker 23 (particle diameter: about 10 mm). Further, the clinker 23 is pulverized into small particles by a pulverizer 31 and transported to the cooler 14, where the clinker 23 is cooled to almost normal temperature.

In FIGS. 1 and 2 corresponding to FIGS. 8 to 9 of the prior art showing a first embodiment of a preheating device comprising the preheater 8 and the connecting pipe 25, etc., reference numeral 8 denotes a preheater, and 24 denotes a preheater. The cyclone 25 of the preheater 8 is a connecting pipe connecting between the cyclones, 26 is a cyclone inner cylindrical part constituting the tip of the connecting pipe 25, and 27 is a cyclone lower opening / closing provided on the lower part of the cyclone 24. The SP damper 32 is a weight for the SP damper 27.

Reference numeral 24 'denotes an upper cyclone; 25', a chute portion continuously provided below the upper cyclone 24 ';
Is an SP damper for opening and closing the lower part of the upper cyclone, and 32 'is a weight for the damper 27'. In firing step II,
As shown in FIG. 7, a plurality of (usually 4 to 5) preheaters 8 configured as described above are connected and installed by connecting pipes 25. The above configuration is the same as that of the related art shown in FIGS.

In the embodiment of the present invention, the shape of the flow passage in the connecting pipe 25 is improved. That is, FIGS.
In FIG. 2, reference numeral 29 denotes a flow path forming member,
5, the flow path of the raw material 22 in the connecting pipe 25 has a large cross-sectional area, that is, an enlarged flow path 29a and a reduced flow path 29b having a large flow path area. As described above, the raw materials 22 are alternately arranged along the flow.

During operation of the cement plant equipped with such a preheating device, the raw material 22 having a relatively large particle size collected by the upper cyclone 24 'is deposited on the SP damper 27'. When the weight of the raw material deposited on the damper 27 'is
When the weight exceeds 2, the SP damper 27 'opens, and the deposited raw material 22 passes through the SP damper 27'. Then, the raw material 22 is dispersed and mixed with the high-temperature gas 28 flowing from the lower part of the connecting pipe 25, and is transferred to the inner wall surface of the cyclone 24 while exchanging heat with the high-temperature gas 28. In the cyclone 24, the raw material 22 having a relatively large particle size is pushed by a large centrifugal force to the inner wall surface of the cyclone 24, and then collected by an SP damper 27 provided below the cyclone 24. You. On the other hand, the raw material having a relatively small particle size is collected inside the cyclone 24, and is conveyed in the direction of the upper cyclone 24 'via the upper connecting pipe 25 while rotating through the inner cyclone cylindrical portion 26.

During such operation, the raw material 22 is connected to the connecting pipe 2.
5, the flow path in the connecting pipe 25 is formed by the bellows-shaped flow path forming member 29 so that the enlarged flow path 29 a and the reduced flow path 29 b alternately continue. Is a decelerating flow in the expansion flow path 29a and an accelerating flow in the reduction flow path 29b, and the repetition of the flow increases the turbulence of the flow.

Therefore, the dispersion of the particles of the raw material 22 in the connecting pipe 25 is promoted, and even if a lump is mixed in the raw material 22, this is easily dispersed, and the heat exchange between the raw material 22 and the high-temperature gas 28 is efficiently performed. Done. That is, the length of heat exchange between the raw material 22 and the high-temperature gas 28 in the preheater 8 is shortened, and the number of stages of the preheater 8 can be reduced.

3 and 4 show a second embodiment of the present invention. FIG. 3 is a view corresponding to FIG. 1, and FIG. 4 is a view taken in the direction of arrow A in FIG. In this embodiment, the flow path forming member 29 provided inside each connecting pipe 25 is formed by alternately arranging enlarged flow paths 29a having a large cross-sectional area and reduced flow paths 29b having a small cross-sectional area, and The space between the flow path 29a and the reduced flow path 29b is formed in a curved manner. Other configurations are the same as those of the first embodiment shown in FIGS. 1 and 2, and the same members are denoted by the same reference numerals. The operation and effect of this embodiment are the same as those of the first embodiment shown in FIGS.

FIGS. 5 and 6 show a third embodiment of the present invention. FIG. 5 is a view corresponding to FIG. 1, and FIG. 6 is a view taken in the direction of arrow A in FIG. In this embodiment, the flow path forming member 29 provided inside each connection pipe 25 is configured such that enlarged flow paths 29a and reduced flow paths 29b are alternately arranged, and the cross-sectional shape in the longitudinal direction of the flow path has a curvature. Are formed in a rosary shape in which the swelling portion and the squeezed portion having the shape are alternately formed. Other configurations are the same as those of the first embodiment shown in FIGS. 1 and 2, and the same members are denoted by the same reference numerals. The operation and effect of this embodiment are the same as those of the first embodiment.

[0029]

As described above, according to the present invention, since the accelerating / decelerating flow path in which the expansion flow path and the reduction flow path are alternately combined in the connecting pipe is provided, the flow of the raw material in the flow path is accelerated. And the deceleration flow are repeated to increase the turbulence of the flow, which promotes the dispersion of the particles of the raw material in the connecting pipe, and even if there is a lump in the raw material, this is easily dispersed, and the raw material and the high-temperature gas are dispersed. Can be efficiently performed.

Accordingly, the length of heat exchange between the raw material and the high-temperature gas in the preheater is shortened, the number of stages of the preheater can be reduced, the preheater can be reduced in size and size, and the apparatus cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a preheating device of a cement plant according to a first embodiment of the present invention.

FIG. 2 is a view taken in the direction of arrow A in FIG. 1;

FIG. 3 is a diagram illustrating a second embodiment of the present invention and corresponding to FIG. 1;

FIG. 4 is a view taken in the direction of arrow A in FIG. 3;

FIG. 5 is a view corresponding to FIG. 1 showing a third embodiment of the present invention.

6 is a view as viewed in the direction of the arrow A in FIG. 5;

FIG. 7 is a system diagram showing a manufacturing process of a cement plant.

FIG. 8 is a diagram corresponding to FIG. 1 showing the prior art.

9 is a view as viewed in the direction of the arrow Z in FIG. 8;

[Explanation of symbols]

 Reference Signs List 8 Preheater 13 Kiln 24 Cyclone 25 Connecting pipe 25 'Chute part 27 SP damper 29 Flow path forming member 29a Expansion flow path 29b Reduction flow path I Raw material process II Firing process III Finishing process

Continued on the front page (72) Inventor Kazumasa Mihara 4--22 Kannon Shinmachi, Nishi-ku, Hiroshima City Inside Mitsubishi Heavy Industries, Ltd. Hiroshima Works (72) Inventor Kenji Shinya 4-622 Kannon Shinmachi, Nishi-ku, Hiroshima City Mitsubishi Heavy Industries Hiroshima Manufacturing Co., Ltd.

Claims (2)

[Claims] In a cement plant sintering process provided with a preheating device in which a preheater for heating a raw material with a high-temperature gas is connected in a plurality of stages by a connecting pipe, the connecting pipe has a large flow path area inside. A preheating apparatus for use in a cement plant sintering process, wherein the preheating apparatus is configured as an acceleration / deceleration flow path in which flow paths and reduced flow paths having a small flow path area are alternately combined along a longitudinal direction. 2. The method according to claim 1, wherein the acceleration / deceleration flow path is formed by alternately combining the enlarged flow path and the reduced flow path on a tubular flow path forming member inserted into the connection pipe. Preheating device used for cement plant sintering process.