JPS5815050A - Apparatus for baking cement powder raw material or like - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for firing cement powder raw materials, and more particularly to an improvement in a rotary kiln firing apparatus having a preheating device with a calcining furnace.

An example of a rotary kiln firing apparatus as a typical prior art is shown in FIG. 1. The rotary kiln (a)
Burner (b) and clinker cooler (+1) are installed on the front side of the kiln.
A preheating device (d) with a calcining furnace is provided on the bottom side of the kiln. The preheating device with a calciner (d) is a floating heat exchanger that connects a plurality of collectors (f) and a connecting duct (g), and a calciner (.
), cement powder raw materials such as limestone and clay are input through the input chute (h), descend while being preheated by heat exchange with gas in a suspended state, and run through an independent burner (1). - It is almost completely calcined in the Hakamatsu calcining furnace (・) and then transferred to the collector (j3
The calcined raw material is fed into the rotary kiln (al) from the bottom of the kiln through (k). While moving toward the front of the kiln, the calcined raw material is heated by hot gas from the burner (b) into the rotary kiln (al).
The clinker is further heated to produce a liquid phase in the firing section (12), and the clinker production reaction is completed, and the clinker is transferred to the clinker cooler (a).
to move to.

Figure 2 shows a cross section of the rotary kiln (1), and heat transfer within the kiln occurs in the rotational direction (raw material (1) deposited on the R1 side).
The heat transfer area is not very large, and therefore the heat transfer efficiency is not good, especially when the heat transfer is about 8
In the heating section (al) for raising the temperature of the calcined raw material at 40° C. to the temperature at which liquid phase component formation starts, the amount of heat transfer decreases due to a decrease in the hot gas temperature. When the firing amount of the burner (b) is increased to increase heat transfer in the heating section, the firing temperature in the rotary kiln increases and a large thermal load is applied to the firing section (a2). As a result, the refractories are likely to burn out, and when the diameter of the kiln is increased to reduce the unit heat load, the heat radiation area and installation area become large.

The present invention solves the above problems and is characterized in that the heat transfer efficiency in the rotary kiln is improved by providing means for effectively increasing the heat transfer area on the side of the kiln bottom in the rotary kiln. The purpose is to obtain a very large heat transfer area in the region from raw materials to the production of liquid phase components, improve heat transfer efficiency, and downsize the kiln.

In order to achieve these objectives, the firing device for cement powder raw materials, etc. of the present invention is provided with a powder raw material scraping means (hereinafter referred to as a lifter) between the heating section on the bottom side of the rotary kiln and the firing section on the front side of the kiln. The calcined raw material, which has been almost completely decarburized in the preheating device with a calcining furnace, is fed into the rotary kiln from the bottom side of the heating section and heated while being moved toward the front of the kiln by the rotation of the rotary kiln. Then, the calcined raw materials that reached the area where the 7-tater is installed are scraped up by a lifter and exchanged floating heat with the combustion exhaust gas of the burner (3), and the calcined raw materials floating in the combustion exhaust gas are collected in the heating section. It is characterized in that the temperature is efficiently raised to below the liquid phase component formation temperature by appropriately retaining the clinker in the heating section, and the subsequent clinker formation reaction is carried out in the firing section.

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

FIG. 8 is an overall configuration diagram of the first embodiment of the present invention.

Fig. 4 shows an enlarged vertical cross-sectional view of the rotary kiln and its vicinity. In each drawing, solid arrows indicate the flow of solids such as kriska, and dashed arrows indicate the flow of gases such as combustion exhaust gas. A burner (3) is provided on the front (2) side of a rotary kiln (1) to be described later, and a clinker cooler (4) is disposed opposite to the rotary kiln (1). On the kiln bottom (5) side, collectors (6) are arranged in five upper and lower stages.
) are connected to each other by a connecting duct (7), and are provided with a preheating device (8) having a calcining furnace aQ equipped with an independent burner a. The upper part of the preheating device (8) has an input chute (9) for feeding powdered cement raw materials such as limestone and clay, and the calcination furnace shaft has an air extraction duct r1 from the clinker cooler (4).
tJ is connected. The lowest collector (raw material shoe from 61) connected to the calciner shaft (III is the lower part of the calciner α and the kiln, which is connected to the input pipe α4 facing the rotary kiln bottom (5) A high-temperature separator al is installed in the middle of the duct connecting the rotary kiln (1) to the rotary kiln (1). 5) Coarse coal, for example, is supplied into the furnace as auxiliary fuel from the side.Therefore, an airflow drying device for drying the coarse coal is provided with an input hopper.This airflow Relatively high-temperature air from the tarinka cooler (4) is introduced into the airflow dryer aη via a fan or duct a11, and therefore the coarse granulated coal fed from the car is fed into the airflow dryer aη. , it is dried while floating in the relatively high temperature air, and dedicated to the collection cyclone.Kentake is a right-leg collection cyclone (to).
Collected carbonized charcoal, stored in eDK, fixed quantity feeder 0
1) Coarse coal supply sheet (to)
It is fed into the Tari Kiln (1) through the.

On the other hand, the cement raw material powder of about 46P is in the preheating device (8)
The rotary kiln (1) and the exhaust gas from the calcining furnace are preheated in a suspended state in countercurrent to the exhaust gas from the calcining furnace (II).
The calcined raw material is collected in the lowermost collector (6) and sent from the raw material chute α to about 840°C.
It is put into the rotary kiln (1) at a temperature of As the rotary kiln (1) rotates, the calcined raw material and coarse charcoal move to the front of the kiln (2), but during this time, they are converted into a liquid phase by the relatively low temperature combustion of the coarse charcoal and the combustion gas from the burner (3). It is efficiently heated to below the formation temperature (for example, 1° to 100°C).

Thereafter, it is heated to form a liquid phase to complete the clinker production reaction, and is then granulated and fired. Thus, the rotary kiln (
1) The bottom of the kiln (5) becomes the inner heating part (2), and the front of the kiln (
2) The closer side becomes the firing part (2).

The present invention has a lifter (c) in the area on the front side of the kiln of the heating section (to).
In this work, the diameter of the heating part (c) is expanded from the girder lid (c) installation area (to) to the bottom of the kiln (5), and the diameter is larger than the firing part (c) on the front side of the kiln. The diameter d! For example, it can be an enlarged diameter part (goods) of 1.8 to 1.44,
7. As shown in Fig. 6,
They are arranged in a staggered manner. (The arrangement and number of stages of the slides are not limited to this.) Also, the lifter (2)
As shown in Fig. 6, a protruding refractory is incorporated into the kiln's lining bricks, and the calcined raw material is The raking height is increased. The raking height is determined by the above-mentioned inclination and radial dimension, but since the radial dimension is affected by strength issues and thermal shock, it is better to decide the inclination and radial dimension by considering these conditions. .

The raw material for seaweeding is passed through the rotary kiln (from the raw material chute side).
1) It is introduced into the heating section (end) from the end (5) of the kiln and heated while moving toward the front (2) of the kiln, which does not extend to the first stage of the rotary kiln. If auxiliary fuel is used, e.g.
Coarse coal with a diameter of 2 mm is fed into the rotary kiln (11) via the coarse coal feed (2).The coarse coal is combusted in the heating section (to) with some of the coarse coal being piled up. The calcined raw material is transferred to the front (2) side of the kiln while being heated.

A part of the calcined raw material reaches the lifter installation area (2) and is scraped up by the ivy, suspended in the hot gas flow and heated. Since heat transfer in this state occurs on the surface of the raw material particles as they encounter the gas flow, the heat transfer area is much larger than that on the surface of the deposited material in a normal rotary kiln. Furthermore, since the coarse grained coal of Mosho is burned at this stage by the excess secondary air of the burner (3), a very large heating effect is often obtained in this region.

A part of the calcined raw material and coarse coal suspended in this way is moved to the kiln bottom (5) as shown by the arrow (a) by the gas flow.
In this example, the area closer to the bottom of the kiln (5) than the heating section (toward) where the lid is installed is an enlarged diameter section (goods), and in this enlarged diameter section (2), the gas Since the flow stops expanding and the gas temperature is lowered by heat exchange over the calcined raw material, the gas flow rate decreases. As the flow rate gradually decreases, the floating calcined raw material and coarse coal settle into the heating section (2).

The remaining part of the floating calcined raw material is led together with the kiln exhaust gas to the high temperature separator AS and collected there.

In this way, the calcined raw material circulates in the heating section (c) of the rotary kiln +1), so liquid phase is generated due to the increased residence time, air flow heating, and increased heating effect due to the combustion of coarse coal. It is effectively heated to below temperature (1,100°C).

The raw material that has passed through the lifter installation area (towards) is transferred to the firing section r24.
The clinker production reaction is carried out in the same way as in a normal rotary kiln, and the product is granulated and fired. Since the clinker production reaction is an exothermic reaction, the firing section is heated to a temperature of 80 to 80 m
It is sufficient to have a length of 5 m.

In this embodiment, the lifter installation area (A) is within the range where the liquid phase component of the firing part (goods) is located closer to the kiln bottom (5) than the area where the liquid phase component is generated. (
There is no problem in entering a part of the area that is considered to be a property.

In addition, in this embodiment, coarse coal as fuel (low-grade coal may be used as fuel) is fed into the rotary kiln (1) from the kiln bottom (5) and temporarily heated in the heating section (c). The effect of raising the temperature of the firing raw material is improved, thereby reducing the amount of fuel burned from the burner (3) to the firing section f24, thereby reducing the thermal load on the Talinka firing section (foundation). In this example, coarse granulated coal is directly charged into the heating section @ together with the calcining raw material, but as shown in Fig. If coarse ash is used as an auxiliary fuel, it can be fed from the granular coal supply chute or from the raw material chute α trench from the lowest collector (6). After the ash is separated, it becomes part of the cement raw material as it is, so no special equipment is required for ash treatment.Also, since the combustion of the coarse coal is almost completed in the heating section, there are no troubles caused by afterburning. It can be avoided as much as possible.

In addition, in this example, high-temperature separators 0!9 are installed to collect the suspended suspended calcined raw materials transported by the gas flow that cannot be settled in the heating section. You don't have to.

FIG. 7 shows a longitudinal cross-sectional view of a rotary kiln and neighboring parts of a second embodiment of the present invention, and parts corresponding to other embodiments are designated by the same reference numerals, and redundant explanation will be omitted. In this embodiment, a constriction part (to) is provided on the front side of the kiln heating part (c), and a lifter (c) is provided in the contraction part of the kiln, and the gas flow rate is By increasing the amount, it is possible to enhance the floating suspension effect of the paper calcining raw material and improve the heat transfer efficiency.

FIG. 8 shows a longitudinal sectional view of a kiln according to an eighth embodiment of the present invention, and parts corresponding to each embodiment are designated by the same reference numerals. It is.

Figures 9 and 10 show a rotary kiln according to a fourth embodiment of the present invention, and parts corresponding to each embodiment are indicated by the same reference numerals. (To)
A concave colored lid (2) is installed on the lining paper brick (2), and the calcined raw material is scraped up in the concave part. Comparing this embodiment with the second embodiment, the pressure loss in the area where the heater is installed is small. Compared to the case where the bent lid protrudes into the high-temperature combustion gas, burnout of the lifter portion is avoided as much as possible, resulting in a longer life. As shown in Fig. 11, the concave color 7 (7) is tilted toward the kiln rotation direction (can) when lifting.
θ), it is possible to increase the raking height.

FIG. 12 shows a rotary kiln according to a fifth embodiment of the present invention, and parts corresponding to each embodiment are designated by the same reference numerals. In this embodiment, a throttle member is provided and the lifter installation area (A) is formed. A convex lifter (c) is provided on the butt side, and a concave rick is provided on the front side of the kiln. FIG. 18 shows a modified concave lifter (80A) for a rotary kiln according to a sixth embodiment of the present invention, with at least one convex lifter part (25A) in the concave portion.
This is what was installed. As in the fourth embodiment, pressure loss in the lifter installation area is small, and burnout and wear of the convex lifter portion (25A) are minimized, resulting in a long life. Also, compared to the concave lifter (to) in Fig. 11, the convex lifter (2)
5A) is installed, the amount of calcined raw material scraped up increases, and more calcined raw materials can be suspended in the gas flow.

14 and 16 show a rotary kiln according to a seventh embodiment of the present invention, in which an annular recess is provided on the kiln bottom (5) side from the firing section of the straight-body rotary kiln (1). Convex portions (25B) are arranged in a row inside. Compared to the eighth and fourth embodiments, the pressure loss is smaller, and burnout and wear of the licks are minimized. Also, the amount of raking is sufficiently large.

The firing apparatus of the present invention can produce limestone, alumina, etc. It is also used for firing powder raw materials.

fart According to the present invention described above, the following effects can be obtained.

1) The length of the firing section of the kiln is 80 to 85 m as mentioned above, but the length of the heating section is limited because the temperature of the heating section can be effectively raised to below the liquid phase formation temperature by using the airflow method in combination. As a result, the entire kiln can be made smaller by about 20 to 80%, and the installation area and heat radiation area can be reduced. In addition, the amount of wet coal in the exhaust gas of the kiln is reduced due to efficient heat exchange in the heating section, so troubles in the sealing section can be avoided as much as possible.

2) Due to the efficient airflow heating effect control in the heating section and the increased heating effect when coarse coal is used in combination, the amount of fuel burned in the main burner of the kiln can be reduced accordingly. The heat load on the firing zone is reduced, and burnout of the refractory is minimized. Furthermore, if the heat load is kept the same, the diameter of the kiln can be made smaller, so the amount of consumption of refractories is reduced.

8) Equipment costs can be reduced by downsizing the kiln, 4)
Since the amount of fuel burned in the firing section is reduced, the amount of No. generated is reduced.

5) When pulverized coal is used as an auxiliary fuel, it is carried out of the kiln along with the gas flow, where it burns and causes trouble.Since coarse granulated coal is used, this problem does not occur. Since there is a tenth residence time in the heating section, complete combustion can be achieved. Furthermore, the use of coarse coal reduces the power required to crush the coal.

[Brief explanation of drawings]

FIG. 1 is a partial vertical cross-sectional view showing a schematic configuration of a conventional single kiln firing apparatus, and FIG. 2 is a cross-sectional view of the rotary kiln taken along the line -1 in FIG. Figure 8 shows the first embodiment of the present invention.
FIG. 4 is an enlarged longitudinal sectional view of the rotary kiln and its vicinity, FIG. 5 is a diagram of the girder installation area, and FIG. 6 is a diagram of the lifter section. FIG. FIG. 7 is a vertical cross-sectional view of a rotary kiln and its vicinity according to a second embodiment of the present invention, and FIG.
FIG. 9 is a vertical sectional view of a rotary kiln according to an eighth embodiment of the invention, and FIG.
The figure is a sectional view taken along the line X-X of Zheng 9, and the figure 11 is its modified concave shape 7.
12 is a longitudinal sectional view of a rotary kiln according to a fifth embodiment of the present invention, and FIG. 18 is a sectional view of another concave lifter portion of a rotary kiln according to a sixth embodiment of the present invention. 14 is a vertical sectional view of a rotary kiln according to a seventh embodiment of the present invention, and FIG.
The figure is a cross-section diagram of Figure 4. (1)...Rotary kiln, (2)...Kiln front, (3)...
・Burner, (4)...Clinker cooler, (5)...Kiln bottom, (6)...Collector, (7)...Connection duct, (8)...
・Preheating device, (9)...Input chute, sintering furnace,
Port 0: burner, (13: bleed air duct, a)
Raw material chute, fits...input pipe, aS...high temperature separator,
(IQ...Input hopper, aη...Airflow dryer, 6e
...Fan, (to)...Duct, (1)...Coal collection cyclone, clD...Dry coal hopper, Four fists/Coarse coal supply chute, (C)...Fist heating section, Q4...Calcining section ,(c)
(25A) (25B)...Convex lifter, (2)...S7
Equipment area, (Foundation)... Expanded diameter part, (To)... Lining brick, Brick... Throttle part, ell (80A)... Concave lifter, a
ll...Quantitative feeder

Claims (1)

[Scope of Claims] (1) A rotary kiln is provided with means for scraping up powder raw material on the front side of the kiln bottom side heating section, and ``the calcined powder raw material is thrown into the kiln bottom side of the heating section; The rotary kiln is moved toward the front of the kiln by the rotation of the rotary kiln, and at least a part of the powdered raw material that has reached the scraping means installation area is suspended in hot gas by the scraping means, and after heat exchange, it is captured in the heating section. A firing device for cement powder raw materials, etc., which is configured to collect powder raw materials, and further to fire the powder raw materials heated in the heating section in the front firing section of the rotary kiln. (21) An apparatus for burning cement powder raw materials, etc., according to claim 1, characterized in that auxiliary fuel is combusted in the heating section of the rotary kiln. (3) Exhaust gas flows into the exhaust gas duct of the rotary kiln. Claim 1 or 2, characterized in that a separator is provided for separating the powder raw material inside and returning it to the heating section.
A firing device for cement powder raw materials, etc., as described in Section 1. (4) In the rotary kiln h, the kiln bottom side is expanded from the raking means installation area. A firing device for the cement powder raw materials described above. (5) An apparatus for firing cement powder raw materials, etc., as set forth in claim 1, item 2, or claim 8, wherein in the rotary kiln, the area in which the scraping means is provided is reduced in diameter. (61) In the rotary kiln, the area in which the scraping means is provided is enlarged in diameter, and the scraping means is provided within the enlarged diameter portion. (7) In the mouth kiln, a concave portion is provided in the refractory material in an area where a scraping means is provided. Or firing equipment for cement powder raw materials, etc. as described in Section 8.