JP2918111B1 - Method and apparatus for preheating cement raw material and method of using the apparatus - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To reduce the pressure loss while securing the dust collection efficiency of a cement raw material preheating device that uses a cyclone in multiple stages, and to reduce the size and height of the cyclone to improve economic efficiency. Improve. SOLUTION: An uppermost cyclone 14 and / or a lowermost cyclone has a cylindrical portion 21 having a linden-type inlet duct 20, and a substantially inverted truncated cone-shaped upper cone 22 connected to a lower end of the cylindrical portion 21. A substantially inverted conical lower cone 25 having a discharge port 23 at a lower portion connected to a lower portion of the upper cone 22 so as to insert a lower end of the upper cone 22; 26, the inner diameter of the lower end of the upper cone 22 is 0.9 to 1.1 times the inner diameter d of the inner cylinder 27, that is, D1 = 0.9d. ~
It is configured to be 1.1d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for efficiently and economically preheating a granular cement raw material with low pressure loss.
The present invention relates to a cement raw material preheating device and a method of using (operating method) the cement raw material preheating device.

[0002]

2. Description of the Related Art Cyclones for preheating cement raw materials (suspension preheaters or suspension preheaters with a calciner) are stacked in series in 4 to 6 stages and have an average particle size of 20 μm.
The raw material is preheated to about 800 ° C. and partially calcined (decomposition of limestone).
Nm ³ / h, dust concentration 1000 to 1500 gr / Nm ³ , temperature 300 to 900 ° C, cyclone cylinder inner diameter 5 to 10 m
It has refractory-lined structure and extremely special usage conditions (large capacity, high temperature, high concentration) compared to normal cyclones.
Theoretically, it was calculated that the critical particle diameter was about 40μ, and the dust collection efficiency was 2
Since it is 0 to 30%, the system should not be established. However, in reality, a dust collection efficiency of 80 to 95% is obtained, which is considered to be due to adhesion and cohesion of the cement raw material. The performance required of such a cyclone for preheating cement raw materials is that it is slightly short (the equipment cost is low) and the pressure loss is low (the power consumption is low). Regarding the dust collection efficiency, the higher the cyclones at the top and bottom, the more heat consumption can be reduced.
Since the cyclone in the middle stage has little effect on heat consumption, high efficiency is not necessarily required by emphasizing pressure loss.

Conventionally, a cyclone 1 as shown in FIGS. 10 and 11 is provided with a suspension preheater (suspension preheater system, abbreviated as "SP system") without a calcining furnace of a cement raw material preheating apparatus, or with a calcining furnace. A plurality of stages are used for a suspension preheater (new suspension preheater method, abbreviated as “NSP method”) and the like. The body of the cyclone 1 has a cylindrical body 2 and an inverted conical body 3
Consists of At the center of the cylindrical body 2 is an inner cylinder 4 from above.
Is inserted. The outer periphery of the cylindrical body 2 is connected to an inlet duct 5 for introducing exhaust gas from a firing device such as a lower cyclone or rotary kiln in a tangential direction. The exhaust gas introduced from the inlet duct 5 descends while turning along the inner peripheral surfaces of the cylindrical body 2 and the inverted conical body 3. Exhaust gas that has descended along the inner wall at the lower portion of the inverted conical body 3 reverses and rises, and separates from the particulate cement raw material mixed with the exhaust gas. The exhaust gas from which the powdery and granular materials have been separated and purified is sucked into the inner cylinder 4 and the outlet pipe 6.
Is discharged through. In FIG. 11, the outlet pipe 6 and the inner cylinder 4
Is sealed with bellows 7 as an example.

[0004] Velocity of exhaust gas flow into cyclone 1 vi
Is, for example, 15 to 20 m / s, and the outlet speed vo to the inner cylinder 4 is usually 18 to 20 m / s. Assuming that the height of the inlet duct 5 is A, the depth of the inner cylinder 4 protruding into the cylindrical body 2 is about 0.3 to 0.5A. FIG. 10, FIG.
Even if the cyclone 1 as shown in FIG. 1 is arranged in a plurality of stages to constitute a suspension preheater, it is difficult to sufficiently recover the cement raw material contained in the exhaust gas in a dust state. In Japanese Utility Model Publication No. 7-46357, there is disclosed a cyclone having a shape in which a diameter is temporarily inclined near a portion where a gas flow reverses and rises in the middle of the inverted conical body 3 of the cyclone 1 as shown in FIG. Prior art is disclosed for use in a lime fluidized bed firing apparatus. In the present specification, such a cyclone having an inverted conical body whose inner diameter once expands is referred to as a "coma-type cyclone".

Also, Japanese Utility Model Publication No. 3-4369 discloses that
Between the cylindrical part and the cone part, there is a main body middle part whose inclination is gentler than the cone part, the inlet duct has a square cross-sectional shape with a horizontal floor surface, and the gas exhaust pipe is eccentrically arranged on the side away from the inlet duct Cyclones that have been described. And, as each operation effect, the swirl flow is guided downward, the number of swirls of the swirl flow generated inside the cyclone is reduced, and the pressure loss can be suppressed, without reducing the gas flow velocity at the cyclone inlet portion. Inflow into the cyclone body increases the swirl flow velocity and improves dust collection efficiency.Dust volume decreases due to short-circuit flow from the inlet to the inner cylinder, increasing pressure loss, but improving dust collection efficiency Is described as having a great effect. However, the number of swirling of the swirling flow can be reduced to reduce the pressure loss, but the dust collection efficiency is definitely reduced, and conversely, the dust collection efficiency can be improved, but the increase in pressure loss is inevitable. If only the effects of either low pressure loss or high efficiency remain due to the combination of opposing effects, there must be special restrictions on the cyclone shape and operating conditions.

[0006] At least, the condition must be such that dust does not accumulate on the horizontal bottom surface of the inlet duct. However, in the cyclone for preheating cement raw material, the direction of gas flow changes immediately before the inlet, so that the dust accumulates and grows (particularly at the inlet cross section). Corner portion) always occurs, so that the effect cannot be stably maintained. For more information,
Japanese Patent No. 57065 relatively theoretically states that pressure loss can be reduced without lowering dust collection efficiency. Japanese Utility Model Publication No. Hei 3-4369 describes the exact opposite, but either one is not necessarily wrong and may be true under certain specific conditions.
That is why experts say that cyclones are a product of the devil. As mentioned above, the two arguments are synonymous, and in any case, in the cyclone for preheating cement raw material, the flow velocity setting is focused on improving the dust collection efficiency at the uppermost and lowermost stages and reducing the pressure loss at the intermediate stage. is necessary.

In Japanese Utility Model Publication No. 62-42292, a guide for providing a powdery material is provided in the lower half of the cone so that the efficiency of heat exchange between the powdery material and gas in the cyclone is reduced. A cyclone separator for a heat exchanger is described which prevents the re-scattering phenomenon of the particles and achieves a high separation efficiency. Regarding re-dispersion, 7-4635
As described in detail in Japanese Patent Application Publication No. 7-107, in a certain range of dimensional relationships, re-scattering can be prevented, dust collection efficiency can be greatly improved, and pressure loss can be reduced at the same time by lowering the swirling flow velocity of the portion. is there. However, in the cyclone for preheating cement raw material, since the raw material has an adhesive property, in the Japanese Utility Model Publication No. 62-42292, the cyclone collides and adheres to the groove and grows from the starting point. Become. On the other hand, 7-4
In Japanese Patent No. 6357, a stable high efficiency can be obtained because there is no sticking because the swirling downward flow of the raw material is not hindered.
However, there were complaints that the device was taller and could not meet the high demand for reducing pressure loss.

Japanese Utility Model Publication No. 59-42121 discloses that a dust-containing gas flow introduction path is spirally descended and gradually connected to the outer peripheral wall of a cylindrical body to extend the introduction path upper wall. There is disclosed a dust collector in which a guide plate is provided in a cylindrical body, an introduction path bottom wall is formed to be inclined toward the cylindrical body, and further, a conical gas discharge portion is provided at an upper end of the cylindrical body. . As a function and effect, the forcible descent speed acts by the upper wall of the dust-containing gas flow introduction path and the guide plate, and the dust falls smoothly into the inverted conical hopper.
The dust collection efficiency is high because it does not sink into the top, and the bottom wall of the dust-containing gas flow introduction path is inclined, so that dust does not accumulate, it is collected smoothly in the hopper, and the pressure loss can be kept low. It is described as possible. However,
In reality, giving a forcible descending speed decreases the swirling flow rate and the number of swirling, so that the pressure loss is reduced but the dust collection efficiency is also reduced. Further, since the inclination angle of the bottom wall of the gas flow introduction passage becomes smaller as approaching the cylindrical body, dust accumulation cannot be completely prevented, and the effect of reducing pressure loss cannot be satisfied.
For this reason, the intermediate stage of the suspension preheater does not require high dust collection efficiency, so it can be used. However, for the uppermost stage and the lowermost stage, the development and commercialization of a high-efficiency, low-pressure-loss cyclone has been strongly desired.

Further, Japanese Patent Application Laid-Open No. 10-87355 discloses a cement raw material preheating apparatus characterized in that the lowermost and uppermost cyclones of the cement raw material preheating apparatus have higher dust collection efficiency than the remaining cyclones. Have been. By adopting a top-type cyclone as an example of a high-efficiency cyclone and increasing the inlet speed to 25 m / s or more,
It is described that the circulation of the raw material in the system is minimized, and effects such as a reduction in power, an improvement in thermal efficiency, a stable operation, an increase in production, and a stable and improved product quality can be obtained. Certainly, the effects of improvement in thermal efficiency and stable operation are recognized, but the inlet speed is 25m
/ S or more, the pressure loss increased. However, the recent trend is that thermal efficiency remains the same,
It is considered that the effects of reduction in power and increase in production volume obtained by reducing the pressure loss are larger, and simply reducing the cyclone inlet flow velocity and increasing the outlet pipe diameter is required to achieve the desired optimum. As described above, no performance is obtained.

[0010]

SUMMARY OF THE INVENTION The inventor of the present invention has been carrying out various trials and errors on the improvement and operation of a cyclone for a cement raw material preheating apparatus for many years, and has been required for each stage cyclone (dust collection efficiency and pressure loss). Have been found to be different, and have been designed and improved to achieve that performance. As a result, the middle stage cyclone only needs to consider the reduction of pressure loss and stable operation, but the highest stage and the lowest stage cyclone are most economically efficient if the performance shown in Table 1 is realized. I found that. Furthermore, the experiment was repeated with various shapes and dimensions, and the design and improvement to achieve the target performance were successful. The uppermost cyclone of the prior art shown in Table 1 has a structure shown in FIG. 10 and is changed in size and shape so as to be suitable for the uppermost cyclone. The lowermost cyclone of the prior art is shown in FIG.
The size and shape of the structure shown in (1) were changed so as to be suitable for the lowermost cyclone. Then, the performance was measured under the same conditions such as the exhaust gas flow rate in the conventional cyclone and the cyclone of the improved technology (the present invention).

[0011]

[Table 1]

Conventionally, each cyclone constituting a suspension preheater is designed to have substantially the same inlet and outlet flow velocity with respect to exhaust gas. Since the temperature of the exhaust gas is higher in the lower stage, the cyclone is larger in the lower stage and the gas viscosity is high, so that the dust collection efficiency as the cyclone is low. Therefore, the fine powder collected on the low temperature side and sent to the high temperature side cannot be collected on the high temperature side, and the fine powder circulates in the suspension preheater system, causing problems such as an increase in pressure loss, a decrease in thermal efficiency, and a hindrance to safe operation. Furthermore, the conventional lower-stage cyclone has a high exhaust gas temperature of 850 to 900 ° C., so the inner cylinder of the cyclone is severely burnt, and the insertion length of the inner cylinder has to be shortened from the viewpoint of life and replacement cost. Efficiency is getting worse.

The present invention has been made in view of the above-mentioned points, and has been made based on the above-mentioned knowledge. An object of the present invention is to provide a low-pressure-loss, high-efficiency upper-stage and / or lower-stage cyclone as a whole apparatus. It is an object of the present invention to provide a method for preheating a cement raw material which is economically enhanced, a method for preheating a cement raw material for performing the method, and a method for using the preheater for cement, that is, an operation method.

[0014]

In order to achieve the above object, a method for preheating a cement raw material according to the present invention is characterized in that a powdery cement raw material is prepared by using a sintering furnace, a granulating furnace or an exhaust gas from a granulating sintering furnace. In a cement raw material preheating method for preheating and separating and collecting a cement raw material mixed in exhaust gas by a multistage cyclone, an uppermost stage (lowest temperature side) and / or a lowermost stage of the multistage arranged cyclones (Highest temperature side) As a cyclone arranged at the (highest temperature side), the required dust collection efficiency (80 to 95%) can be ensured, and the pressure loss can be reduced and the height can be reduced. It is configured to use a high-efficiency cyclone (see FIGS. 1 to 9).

[0015] The cement raw material preheating apparatus of the present invention comprises:
Cement in which powdery and granular cement raw materials are preheated by using an exhaust gas from a firing furnace, a granulating furnace or a granulating and firing furnace, and the cement raw materials mixed in the exhaust gas are separated and collected by cyclones arranged in multiple stages. In the raw material preheating apparatus, among the cyclones arranged in multiple stages, the cyclones arranged in the uppermost stage and / or the lowermost stage have the required dust collection efficiency (8
(0 to 95%), a low pressure loss and a high efficiency cyclone having a structure capable of reducing the pressure loss and reducing the height (FIG. 1).
To FIG. 9).

In this cement raw material preheating apparatus, the uppermost and / or lowermost cyclone includes a cylindrical portion having a Linden-type inlet duct, and a substantially inverted truncated cone-shaped upper cone connected to a lower end of the cylindrical portion. The lower cone of the upper cone is connected to the lower end of the upper cone so as to insert the lower end of the upper cone. An inner cylinder inserted from above, and the inner diameter D of the lower end of the upper cone
1 is 0.9 to 1.1 times the inner diameter d of the inner cylinder, that is, D1 =
It is configured to be 0.9d to 1.1d (see FIGS. 2 to 8).

In the above cement raw material preheating apparatus, the top wall of the lower cone is configured to be substantially horizontal (see FIGS. 2, 4 and 6). In addition, the angle θ of the bottom of the Linden part
It is preferable that 1 is inclined at 45 to 55 ° with respect to the horizontal direction (see FIGS. 6 and 7). In addition, it is preferable that the angle θ2 of the upper cone be 69 ° or more with respect to the horizontal direction (see FIGS. 2, 4, and 6). further,
The upper end inner diameter D2 of the lower cone is the lower end inner diameter D1 of the upper cone.
600 to 1000 mm larger, that is, D2 = D1 +
It is preferable to set the thickness to 600 to 1000 mm (see FIGS. 2, 4, and 6). Further, it is preferable to insert the lower end of the upper cone 200 to 300 mm from the top wall of the lower cone (see FIGS. 2, 4 and 6).

The insertion length L of the inner cylinder of the uppermost cyclone
Is 1.0 to 1.2 times the inlet height a of the inlet duct, that is, L = 1.0a to 1.2a, and the inner cylinder insertion length L of the lowermost cyclone is equal to the inlet height a of the inlet duct. 0.4 ~
It is preferable to configure so as to be 0.6 times, that is, L = 0.4a to 0.6a (see FIGS. 2, 4, and 6).

In the method of using the cement raw material preheating apparatus of the present invention, the uppermost and / or lowermost cyclone in the cement raw material preheating apparatus having the above-described configuration is configured such that the inlet flow from the inlet duct does not accumulate dust. ~ 17m /
s. Further, the method for using the cement raw material preheating apparatus of the present invention is such that the cement raw material preheating apparatus configured as described above is configured such that the flow rate of the cylindrical portion of the uppermost cyclone is 4.0 to 4.5 m / s, and that of the lowermost cyclone. Is used in such a manner that the cylindrical portion has a flow velocity of 4.5 to 5.0 m / s. In order to reduce the height of the cyclone, it is necessary to reduce the diameter of the cylinder, that is, to increase the flow velocity of the cylinder. In a conventional cyclone, the flow rate of the cylindrical portion is about 4.0 m / s, but in the present invention, the flow speed of the cylindrical portion as described above is required.

As described above, the lowermost and uppermost cyclones ensure a certain degree of dust collection efficiency and reduce the pressure loss and the height of the apparatus as much as possible (see Table 1). Further, the inlet portion is of a lindane type, for example, a semi-lindane type (generally more efficient than a tangent line), and the bottom surface of the lindane portion is inclined from the connection with the rising duct. Although the inclination angle θ1 is related to the inlet flow rate, the angle is set to 45 ° to 55 ° as described above as a range in which the performance does not change due to the deposition and growth of the raw material.
It is generally said that the lower the inlet flow velocity, the lower the pressure loss and the lower the dust collection efficiency. However, in the case of a cyclone for a cement raw material preheating device, there is a lower limit of the flow velocity due to deposition and growth of the raw material. The flow rate (pressure loss) can be reduced from the conventional one by the effect of the Linden type described above.

It is generally said that the larger the inner cylinder diameter (the lower the flow velocity), the lower the pressure loss and the lower the dust collection efficiency. However, in the case of a cyclone for a cement raw material preheating device, the dust collection efficiency is secured. Therefore, there is a lower limit. The cyclones other than the uppermost stage have a lower limit in order to prevent the raw material from directly falling from the upper stage. The present invention relates to the following D1 = 0.9d to 1.1d,
Since the dust collection efficiency was improved by the effect of D2 = D1 + 600 to 1000 mm, the flow velocity (pressure loss) can be reduced as compared with the related art. In general, it is said that the longer the cylindrical portion, the lower the swirling flow velocity, so that the pressure loss is small and the dust collection efficiency does not decrease much. There is some performance change depending on the inlet flow rate, inner cylinder diameter, inner cylinder insertion length, cone angle, etc., but it satisfies the target performance (dust collection efficiency, pressure loss) and is optimal to reduce the height of the device as much as possible As the length, the cylindrical portion length H1 is 1.2D to 1.6D at the uppermost stage and 0.7 at the lowermost stage.
D to 0.9D. Also, in general,
It is said that the inner cylinder insertion length L is 1.1 times the inlet height a and the dust collection efficiency is maximum and the pressure loss is also maximum. In the present invention, the uppermost stage is 1.0a to 1.2a, preferably 1.1a. However, since the lowermost stage is so hot that the internal cylinder is severely burned, the dust collection efficiency is not significantly reduced. 0.7a, preferably 0.4a to 0.6a.

The concept of enlarging the cross section in order to prevent re-scattering near the middle of the cone is the same as that of the coma-type cyclone described in Japanese Utility Model Publication No. 7-46357. Is related to the flow velocity / shape / dimension, and the inner diameter D1 at the lower end of the upper cone is 0.9 to 0.9.
It has been found that setting to 1.1d has the least re-scattering. Further, the inner diameter D2 of the upper end of the lower cone depends on the size of the inner diameter D of the cylindrical portion.
No. 46357 has found that re-scattering can be prevented by setting D2 = 0.8D to 1.0D). Needless to say, the smaller the upper end inner diameter D2 of the lower cone, the lower the device height. Generally, it is said that the larger the cone angle, the smaller the pressure loss, and the maximum dust collection efficiency is 75 to 80 °, but the influence of the cone angle on the pressure loss and the dust collection efficiency is not so large. In the case of a cyclone for a cement raw material preheating device, the height of the device can be significantly reduced within a permissible range in terms of performance even at the minimum angle at which the collected raw material can be smoothly discharged. From the inventor's many years of experience, the top row is more than 69 ° upper cone, more than 65 ° lower cone,
It has been confirmed that the raw material can be discharged smoothly if the lower and upper cones are set to 69 ° or more at the bottom. Also,
In the top cyclone described in Japanese Utility Model Publication No. 7-46357, the angle θ2 of the lower cone top wall is set to 15 ° to 45 °.
By setting the lower end of the upper cone to be 200-300 mm from the lower cone top wall with the lower end of the upper cone being 600-1000 mm, even if the lower cone top wall is horizontal, the re-scatter prevention effect does not change and the apparatus height can be reduced. As a result, the present invention has been completed.

According to the present invention, the uppermost cyclone and / or
Or, the dust collection efficiency of the lowermost cyclone is
Alternatively, the pressure loss can be significantly reduced by making the dust collection efficiency of the lowermost cyclone substantially the same as that of the lowermost cyclone. Further, in the uppermost cyclone and / or the lowermost cyclone of the present invention, the same dust collection efficiency can be obtained. It is possible to reduce the size of the cyclone and to reduce the overall height (total length) as compared with the conventional uppermost cyclone and / or lowermost cyclone, and to use such an uppermost cyclone and / or a lowermost cyclone. As a result, the pressure loss is reduced, so that the fan power and the like are reduced, the power consumption is reduced, and the total height of the cyclone is reduced and the size of the cyclone can be reduced, so that the facility cost is reduced, and the dust collection efficiency is not reduced. That is, it is possible to perform preheating of the cement raw material which is economically excellent as a whole without reducing the production amount.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments and can be implemented with appropriate modifications. FIG. 1 shows a cement raw material preheating apparatus according to a first embodiment of the present invention. This embodiment is a case of a so-called suspension preheater system (SP system) in which a cement raw material preheating apparatus is configured by a suspension preheater 10 having no calciner. This suspension preheater 10 has a multi-stage structure shown by C1 to C4 (FIG. 1).
In this example, four stages) cyclones 11, 12, 13,
14. A raw material input section 15 is provided between the third stage cyclone 13 and the fourth stage cyclone 14. Exhaust gas of about 1100 ° C. is guided from the rotary kiln 16 to the first stage cyclone 11, and the temperature drops to about 850 ° C. when collecting the cement raw material. The exhaust gas whose temperature has dropped to about 850 ° C. is guided to the second-stage cyclone 12, where the temperature drops to about 700 ° C. The exhaust gas at about 700 ° C. is guided to the third stage cyclone 13, and the temperature is reduced to about 550 ° C. The exhaust gas at about 550 ° C. is guided to the fourth stage cyclone 14, and on the way, a powdery cement material is supplied from a raw material supply unit 15.
The temperature of the exhaust gas introduced into the fourth stage cyclone 14 together with the cement raw material decreases to about 350 ° C. and is discharged outside the system.

The cement raw material collected by the fourth stage cyclone 14 is mixed into the exhaust gas guided from the second stage cyclone 12 to the third stage cyclone 13,
Separated by the third stage cyclone 13. The separated cement raw material is mixed in the process of guiding the exhaust gas from the first stage cyclone 11 to the second stage cyclone 12, and is separated from the exhaust gas in the second stage cyclone 12. The separated cement raw material is mixed into exhaust gas introduced from the rotary kiln 16 into the first-stage cyclone 11,
It is separated by the first stage cyclone 11 and introduced into the rotary kiln 16.

FIGS. 2 and 3 show the uppermost (fourth) cyclone 14 in the cement raw material preheating apparatus shown in FIG.
Is shown. The uppermost cyclone 14 includes a cylindrical portion 21 having a lindane type, for example, a semi-lindane type inlet duct 20, a substantially inverted truncated cone-shaped upper cone 22 connected to a lower end of the cylindrical portion 21, and an upper cone 22. A lower cone 25 having a discharge port 23 in the lower portion, and a lower end 25 having a substantially inverted conical shape, which is connected to the lower end of the upper cone 22 so as to insert the lower end of the upper cone 22;
Inner cylinder 27 inserted and fixed from above so as to protrude
It consists of 28 is a lindane part. And
The inner diameter D1 of the lower end of the upper cone 22 is the inner diameter d of the inner cylinder 27.
0.9 to 1.1 times, that is, D1 = 0.9d to 1.1
d.

FIGS. 4 and 5 show the lowermost (first stage) cyclone 11 in the cement raw material preheating apparatus shown in FIG.
Is shown. The lowermost cyclone 11, like the uppermost cyclone 14 shown in FIGS. 2 and 3, is connected to a cylindrical portion 31 having a lindane type, for example, a semi-lindane type inlet duct 30, and a lower end of the cylindrical portion 31. An upper cone 32 having a substantially inverted truncated cone shape, and a lower cone 35 having a substantially inverted truncated cone shape having a discharge port 33 at a lower portion connected to a lower portion of the upper cone 32 so as to insert a lower end of the upper cone 32; The upper end is located at the center of the cylindrical portion 31 in the vertical direction and the outlet 3
Inner cylinder 3 inserted and fixed from above so as to project as 6
It consists of seven. 38 is a Linden part. The inner diameter D1 of the lower end of the upper cone 32 is 0.9 to 1.1 times the inner diameter d of the inner cylinder 37, that is, D1 = 0.9d to
1.1d. The lowermost cyclone 11 is made of a refractory material.

FIG. 6 shows details of an elevation around the uppermost cyclone 14, FIG. 7 shows a cross section taken along line AA in FIG. 6, and FIG. 8 shows a plane of the uppermost cyclone shown in FIG. . In addition, the position of the inlet duct 20 is drawn left and right reversed from FIG. 40 is a rising duct for introducing exhaust gas, 41
Is an expansion joint, and 42 is an opening of the inlet duct 20.

In the upper cyclone 14 and the lower cyclone 11 configured as described above, the lower cone 2
5, 35 ceiling walls are formed horizontally. By doing in this way, the height of the top wall of the lower cone can be significantly reduced as compared with the so-called top-type cyclone described in Japanese Utility Model Publication No. 7-46357 in which the outer edge of the top wall is inclined downward. it can. As shown in FIGS. 6 and 7, the angle θ1 of the bottom surface of the linden portion 28 with respect to the horizontal direction is 45 to 5
The angle is 5 °, forming an inclined lindane portion. Also,
The angle θ2 of the upper cones 22, 32 is 69 ° or more with respect to the horizontal direction. Further, the lower cones 25, 3
5 is 600 to 1000 mm larger than the lower end inner diameter D1 of the upper cones 22, 32, that is, D2 = D
1 + 600 to 1000 mm. The lower ends of the upper cones 22 and 32 are inserted and fixed 200 to 300 mm from the top walls of the lower cones 25 and 35.

The above configuration is common to the uppermost cyclone 14 and the lowermost cyclone 11, but the following configuration is different between the uppermost cyclone 14 and the lowermost cyclone 11. Lower cone 25 of top cyclone 14
Is 65 ° or more with respect to the horizontal direction, and the angle θ3 of the lower cone 35 of the lowermost cyclone 11 is 69 ° or more with respect to the horizontal direction. The height H1 of the cylindrical portion 21 of the uppermost cyclone 14 is 1.2 to 1.6 times the inner diameter D of the cylindrical portion 21, that is, H1 = 1.2D to 1.6D.
And the height H1 of the cylindrical portion 31 of the lowermost cyclone 11
Is formed to be 0.7 to 0.9 times the inner diameter D of the cylindrical portion 31, that is, H1 = 0.7D to 0.9D. Furthermore, the inner cylinder insertion length L of the uppermost cyclone 14 is
1.0 to 1.2 times the inlet height a of the inlet duct 20, that is, L = 1.0a to 1.2a, and the inner cylinder insertion length L of the lowermost cyclone 11 is equal to the inlet height of the inlet duct 30. It is formed so that 0.4 to 0.6 times a, that is, L = 0.4a to 0.6a. Although the upper limit of the angles θ2 and θ3 is less than 90 °, the height becomes extremely high as the angle approaches 90 °, so the upper limit needs to be about 75 °.

The cement raw material preheating device configured as described above includes the uppermost cyclone 14 and the lowermost cyclone 1
The inlet flow rate from one inlet duct 20, 30 is 13-17.
It is operated at m / s. In this way, it is possible to prevent dust in the exhaust gas from accumulating in the inlet ducts 20 and 30, and to maintain a low pressure loss. The operation is performed with the outlet flow velocity of the uppermost cyclone 14 being 13 to 15 m / s and the outlet flow velocity of the lowermost cyclone 11 being 15 to 18 m / s. By doing so, a low pressure loss can be maintained, and the lowermost cyclone 11 can prevent powder particles from falling directly. FIG. 1 illustrates the case where four stages of cyclones are installed, but it is of course possible to provide five or more stages. In addition to the rotary kiln, the present invention can be applied to a cement sintering apparatus using a fluidized bed granulation furnace, a spouted bed granulation furnace, or a fluidized bed granulation sintering furnace. Further, the case of a semi-lindane type is described as the lindane type, but it is also possible to use an all lindane type or the like. In this embodiment, the case where the present invention is applied to both the uppermost cyclone and the lowermost cyclone has been described. However, the present invention can be applied to either the uppermost cyclone or the lowermost cyclone.

FIG. 9 shows a cement raw material preheating apparatus according to a second embodiment of the present invention. The present embodiment is a case of a so-called new suspension preheater method (NSP method) in which the cement raw material preheating device is constituted by a suspension preheater 50 having a calciner 52. Parts corresponding to the configuration in FIG. 1 are denoted by the same reference numerals and symbols, and description thereof will be omitted. Exhaust gas from the calciner 52 is introduced into the cyclone 11 at the lowermost stage (first stage). The cement clinker fired in the rotary kiln 16 is supplied to an air quenching cooler (abbreviated as “AQC”) 54.
Cooled by. And the air quenching cooler 54
The air heated to a high temperature by cooling the cement clinker is returned to the calciner 52 as combustion air. Other configurations and operations are the same as those in the first embodiment.

[0033]

As described above, the present invention has the following effects. (1) It is possible to greatly reduce the pressure loss while maintaining the dust collection efficiency of the uppermost cyclone and / or the lowermost cyclone at the same level as that of the conventional uppermost and / or lowermost cyclone. In addition, since the top cyclone and / or the bottom cyclone can be reduced in size and the overall height can be reduced, power consumption is reduced, and
Equipment costs are reduced, without reducing the dust collection efficiency,
As a whole, it is possible to preheat a cement raw material which is excellent in economy and productivity. (2) If the inlet of the uppermost cyclone and / or the lowermost cyclone is of a Linden type, and if the bottom of the Linden part is inclined from the connection with the rising duct, the performance change due to the deposition and growth of the raw material may occur. Can be prevented from happening. (3) Since the lower end of the upper cone is inserted from the lower cone top wall and the lower cone top wall is leveled, it has the effect of preventing re-scattering, and also lowers the height of the lower cone and thus the entire cyclone. be able to.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a schematic configuration of a cement raw material preheating apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory longitudinal sectional view showing a configuration of a cyclone at an uppermost stage (fourth stage) in FIG. 1;

FIG. 3 is a plan view of the cyclone shown in FIG. 2;

FIG. 4 is an explanatory longitudinal sectional view showing a configuration of a lowermost cyclone (first tier) in FIG. 1;

FIG. 5 is a plan view of the cyclone shown in FIG.

FIG. 6 is an explanatory longitudinal sectional view showing an example around the uppermost cyclone.

FIG. 7 is a sectional view taken along line AA in FIG.

FIG. 8 is a plan view around the cyclone shown in FIG. 6;

FIG. 9 is a system diagram showing a schematic configuration of a cement raw material preheating apparatus according to a second embodiment of the present invention.

FIG. 10 is an explanatory longitudinal sectional view showing an example of a conventional cyclone.

FIG. 11 is an explanatory longitudinal sectional view showing another example of a conventional cyclone.

[Explanation of symbols]

 10, 50 Suspension preheater 11 Lowermost cyclone 12, 13 Cyclone 14 Uppermost cyclone 15 Raw material input section 16 Rotary kiln 20, 30, Inlet duct 21, 31, Cylindrical part 22, 32 Upper cone 23, 33 Discharge port 25, 35 Lower cone 26 , 36 Outlet part 27, 37 Inner cylinder 28, 38 Linden part 40 Rise duct 41 Expansion joint 42 Inlet duct opening 52 Calcination furnace 54 Air quenching cooler

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C04B 7/44 F27D 13/00 B04C 5/081

Claims (13)

(57) [Claims] 1. A powdery cement raw material is preheated by using an exhaust gas from a firing furnace, a granulating furnace or a granulating firing furnace, and the cement raw material mixed in the exhaust gas is separated and collected by cyclones arranged in multiple stages. In the method for preheating cement raw material, among the cyclones arranged in multiple stages, as the cyclones arranged in the uppermost stage and / or the lowermost stage, the required dust collection efficiency can be secured, the pressure loss can be reduced, and A method for preheating a cement raw material, characterized by using a low-pressure-loss, high-efficiency cyclone having a structure capable of reducing the hardness. 2. A cement raw material in powder form is preheated by using an exhaust gas from a firing furnace, a granulating furnace or a granulating and firing furnace, and the cement raw material mixed in the exhaust gas is separated and collected by cyclones arranged in multiple stages. In the pre-heating device for cement raw material, among the cyclones arranged in multiple stages, the cyclones arranged in the uppermost stage and / or the lowermost stage can secure the required dust collection efficiency, can reduce the pressure loss, and
A cement raw material preheating device characterized in that the height can be reduced. 3. A cylindrical section having a Linden-type inlet duct, a substantially inverted truncated cone-shaped upper cone connected to a lower end of the cylindrical section, wherein the uppermost and / or lowermost cyclone includes:
The lower cone of this upper cone is connected to the lower end of the upper cone so as to insert the lower end of the upper cone. The lower cone has a substantially inverted conical shape with a discharge port at the lower part, and the upper end of the upper part protrudes as an outlet at the center of the cylindrical part. The inner diameter D1 of the lower end of the upper cone is 0.9-1.
3. The cement raw material preheating apparatus according to claim 2, wherein the ratio is one, that is, D1 = 0.9 to 1.1d. 4. The cement raw material preheating apparatus according to claim 3, wherein the top wall of the lower cone is substantially horizontal. 5. The cement raw material preheating apparatus according to claim 3, wherein the angle θ1 of the bottom surface of the lindane portion is inclined at 45 to 55 ° with respect to the horizontal direction. 6. The cement raw material preheating apparatus according to claim 3, wherein the angle θ2 of the upper cone is 69 ° or more with respect to the horizontal direction. 7. The cement raw material preheating apparatus according to claim 3, wherein an upper end inner diameter D2 of the lower cone is larger than a lower end inner diameter D1 of the upper cone by 600 to 1000 mm, that is, D2 = D1 + 600 to 1000 mm. 8. The cement raw material preheating apparatus according to claim 3, wherein the lower end of the upper cone is inserted by 200 to 300 mm from the top wall of the lower cone. 9. The inner cylinder insertion length L of the uppermost cyclone is 1.0 to 1.2 times the inlet height a of the inlet duct, that is, L
= 1.0a-1.2a, The cement raw material preheating apparatus according to any one of claims 3 to 8. 10. The inner cylinder insertion length L of the lowermost cyclone is 0.4 to 0.6 times the inlet height a of the inlet duct, that is, L = 0.4a to 0.6a. The cement raw material preheating apparatus according to any one of the above. 11. The uppermost and / or lowermost cyclone in the cement raw material preheating apparatus according to any one of claims 2 to 10, wherein an inlet flow rate from an inlet duct is 13 to 17 m / s at which dust is not deposited. Of using the cement raw material preheating device used in the above manner. 12. A cement raw material preheating apparatus which uses the cement raw material preheating apparatus according to any one of claims 2 to 10 so that the flow rate of the cylindrical portion of the uppermost cyclone is 4.0 to 4.5 m / s. How to use 13. A cement raw material preheating apparatus which uses the cement raw material preheating apparatus according to any one of claims 2 to 10 so that the lowermost cyclone has a cylindrical portion flow rate of 4.5 to 5.0 m / s. How to use