JPH09188551A - Grate plate for clinker cooler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grate plate for a clinker cooler capable of reducing the amount of dropped clinkers without deteriorating the heat recovery efficiency. SOLUTION: This grate plate 5 for a clinker cooler is obtained by forming at least a surface to be the downstream side when viewed from the moving direction of clinkers in enlarged parts 13 so as to tilt in the moving direction of the clinkers in the grate plate 5 capable of air-cooling the high-temperature clinkers while transferring the clinkers and is equipped with nozzles 12 for jetting cooling air at a high speed and the enlarged parts 13 for decelerating the air on the downstream side thereof in a jetting part for the cooling air and composed so as to gently feed the cooling air from the enlarged flow passages 13 to the clinkers moving on the top surface of the enlarged parts 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-performance clinker cooler which has a high heat recovery efficiency and is resistant to thermal burnout of the lattice plate, and more particularly to a clinker cooler lattice plate capable of preventing the clinker from falling.

[0002]

2. Description of the Related Art Cement production comprises the steps of crushing and mixing raw materials, firing in a kiln, and cooling to mix gypsum. The clinker cooler is involved in the cooling process in the clinker cooler, which is fired in a kiln at about 1400 ° C.
It is a device that cools the clinker to room temperature.

Although there have been several types of clinker coolers in the past, most of them are the great type coolers shown in FIG. 7 due to natural selection. The clinker cooler 1 is composed of a fan 2, a ventilation duct 3, a wind box 4, a lattice plate 5, an outer wall 6 and a hot air duct 7, and a drive system including a drive device 8 and a frame 9.

The drive system transfers the clinker 11 fed from the kiln 10 to the outlet side by reciprocating the lattice plate 5.

Wind box 4 from fan 2 through ventilation duct 3
The cooling air entering the plurality of nozzles 1 opened in the lattice plate 5.
It is jetted from 2 to the clinker layer 11 placed on the upper surface.

The wind box 4 is partitioned into a plurality of parts in the longitudinal direction and the width direction, and the flow rate of the cooling air is adjusted so as to achieve optimum cooling.

A part of the cooling air ejected from the lattice plate 5 is
After exchanging heat with the high temperature clinker 11, it is used for combustion of the burner for the kiln 10 and residual heat of the raw material, and heat is recovered. The former is called secondary air A and the latter is called tertiary air B. Excess air other than this is C used for the mill and D discharged from the stack.

In order to evaluate the state of heat recovery, the heat recovery efficiency shown by the following equation is defined in the cement plant, and this value is controlled so as to be as high as possible.

[0009] In order to explain the heat recovery rate, FIG. 8 shows the relationship between the cooling air amount and the cooling air temperature after heat exchange. The horizontal axis of FIG. 8 is the air flow rate (kga / kgc) per unit clinker weight obtained by dividing the cooling air flow rate (kga) by the clinker flow rate (kgc). The solid line P is the theoretical line in the case of complete heat exchange, and the broken line Q is the result of the actual plant. The heat quantity exchanged with the clinker is the product obtained by multiplying the outlet air temperature by the specific heat and integrating it by the air flow rate.

Since the amount of air for recovery is limited, in order to increase the heat recovery efficiency, it is necessary to recover heat as efficiently as possible to obtain high temperature air. The heat recovery efficiency used to be about 60% before, but recently it has reached 80%.

[0011]

The following methods are specific means for increasing the heat recovery efficiency.

The clinker transfer rate is reduced.

Increase the height of the clinker.

The jet speed of air is reduced so that the clinker does not convection.

One of the above methods has already been implemented. In a modern cooler, the clinker stays in the cooler for about 30 minutes. If it is attempted to make the clinker residence time longer, it will be difficult in terms of equipment because the clinker cooler installation area will increase.

Another method has already been carried out, but when the bed height is low, the cooling air does not completely exchange heat and exits the clinker bed, so that the bed height is made as high as possible. The problem with this method is that the air flow resistance increases as the bed height increases, and the capacity of the fan increases. At present, it is general that the layer height is around 500 mm.

A further method is to completely avoid the heat exchange by avoiding the phenomenon that the clinker layer fluidizes or the phenomenon that air locally passes.

From the above, at present, only the method is developed. To maximize the heat exchange rate, cooling air may be blown into the clinker uniformly over the entire surface of the lattice plate at a low speed.

However, since the cooling air also serves to cool the lattice plate, when the amount of cooling air decreases, the temperature of the lattice plate rises due to heat transfer from the clinker on the upper surface. Since the temperature of the clinker discharged from the kiln is about 1400 ° C, if the cooling is insufficient, the temperature of the lattice plate will reach 500 ° C or more immediately. For the lattice plate, a casting of a special alloy that can maintain the strength even at high temperature is used, but even if the temperature exceeds 500 ° C., the strength decreases, and when it receives stress, it is easily burnt by heat.

Therefore, in order to improve the heat recovery efficiency, it is necessary to use a lattice plate whose temperature does not rise even if the amount of air is reduced. To meet this requirement, lattice plates having various structures as shown in FIGS. 9 to 11 have been proposed. FIG. 9 shows the simplest perforated plate type lattice plate (a). Further, FIG. 10 shows a lattice plate (b) with oblique holes, and FIG. 11 shows a lattice plate (c) provided with an enlarged portion 13. The size of each lattice plate is 300 mm x 500 mm (200
(including mm), the plate thickness is about 10 mm. The lattice plate shown in FIG. 5 is the most basic type, and the diameter of the nozzle 12 is about 10 mm. The aperture ratio of the nozzle (= total area of the nozzle / horizontal projected area of the lattice plate excluding the overlapping portion) is usually around 5%. The speed at which air is ejected from the nozzle is 10 to 20.
It is about m / s. Clinker particles having a particle size of 10 mm are in a fluidized state at this speed, and the condition of cannot be satisfied. This is because another problem occurs. That is,
This is because the clinker will fall toward the wind box when the ejection speed is reduced. If a high temperature clinker falls, there is a risk of burning the inside of the wind box. Here, it seems that the clinker particles theoretically do not fall if jetted at a wind speed of 10 m / s or more, but the clinker on the lattice plate has the weight of the clinker accumulated in the upper layer and the pressure due to the movement of the clinker. Since two of them work, wind speed of about 10 m / s cannot prevent the clinker from falling.

To solve this problem, the lattice plates shown in FIGS. 10 and 11 have been proposed. In particular, the lattice plate shown in FIG. 11 sets the jetting speed of the nozzle 12 to about 30 m / s and makes it horizontal or downward to prevent the clinker from entering. An enlarged portion 13 is provided on the downstream side of the nozzle 12 and is designed so that the velocity of the cooling air is reduced to about 2 m / s and then jetted to the clinker layer. This structure is a very good method that combines both clinker drop prevention and gentle air ejection.

However, when actually used, since the amount of air is reduced as compared with the conventional case in order to improve the heat recovery rate, the problem of the clinker falling still remains. The reason for this will be described with reference to FIGS. 12 and 13.

Assuming that the thickness of the clinker layer 11 on the upper surface of the enlarged portion 13 is 500 mm, the pressure M1 acting on the upper surface of the lattice plate 5 is increased.
Is about 700 mmAq, and in the case of the lattice plate of FIG. 11, a force of about 7 kg acts on one enlarged portion 13 (5 cm × 20 cm) in the gravity direction.

Assuming that the coefficient of friction between the clinker on the expanded portion 13 and the clinker on the upper layer is f, the expanded portion has f × 7.
A force of kg will act horizontally. If f = 1 as a general value, the downstream side S of the expansion unit 13 in FIG.
The pressure M2 at (cross-sectional area = 5 cm x 4 cm) is 3500 mmAq, which is five times the pressure at rest of 700 mmAq. Since f may be 1 or more in a moment, higher pressure may be generated. The generated pressure acts in the direction of arrow H in FIG. Since the pressure of the jetted air is at most 1000 mmAq, it is impossible to prevent the clinker from falling.
A method of increasing the pressure of the blown air can be considered in order to make the clinker fall to 0, but it is not realistic because the capacity of the fan increases in proportion to the pressure and the sealing of the wind box becomes difficult. .

As described above, the drop of the clinker has not been solved yet due to the generation of pressure accompanying the transfer of the clinker.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a clinker cooler grid plate in which the amount of clinker drop is reduced.

[0027]

A lattice plate of a clinker cooler of the present invention is a lattice plate of a clinker cooler that cools air while transferring a high-temperature clinker, and cool air is jetted at high speed to a jet portion of cold air. In a lattice plate configured to slowly feed cool air from the expansion flow path to a clinker that moves on the upper surface of the expansion part, the expansion plate having a nozzle that expands the air and a downstream part that expands the expansion part. It is characterized in that at least the surface on the downstream side of the part viewed from the moving direction of the clinker is inclined in the moving direction of the clinker.

The lattice plate of the clinker cooler of the present invention is
No nozzle is arranged on the downstream side of the enlarged portion at least in the moving direction of the clinker.

The lattice plate of the clinker cooler of the present invention is
The radius of curvature of the inlet portion of the nozzle is at least 0.
It is characterized in that it is 5 times or more, the length is 2.5 times or more of the gap, and the opening area is 20% or less of the horizontal projected area of the lattice plate.

The lattice plate of the clinker cooler of the present invention is
A flow path is provided on the back surface of the lattice plate provided with the enlarged portion, and a nozzle for ejecting air downward at least from the tip portion of the lattice plate is provided.

The clinker cooler of the present invention is characterized by having any one of the above lattice plates.

In the lattice plate having the above structure, the downstream surface of the enlarged portion is tilted backward, so that no pressure is generated in the enlarged portion due to the transfer of the clinker particles. Therefore, the clinker particles do not flow backward from the ejection holes.

[0033]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the lattice plate according to the present invention. In the figure, the enlarged portion 13 has a width of 250 mm,
The length is 50 mm and the depth is 30 mm.
The ejection nozzle 12 has a height of 5 mm and a width of 80 mm, and three ejection nozzles 12 are provided in the width direction. The aperture ratio of the nozzle 12 is 4%, and the aperture ratio of the enlarged portion 13 is 42%. The surface on the downstream side is inclined at 45 degrees, and its outlet portion is a curved surface with a radius of curvature of 60 mm. The enlarged portion 13 has ribs 1 on its back surface to increase its strength.
Only two 4 are provided in the longitudinal direction.

In order to confirm the effect of the present invention, an experiment was conducted with the test apparatus shown in FIG. 14 in which the same state as the actual machine can be obtained. The test device is a container 30 (width 300 mm, depth 300 mm, height 1000) in which the grid plates 20A, 20B, 20C are fitted.
mm) and a blower 32. Lattice plate 20A,
20B is fixed, and the lattice plate 20C is driven by a drive device (hydraulic cylinder) 34, and reciprocates 30 times per minute in accordance with actual operation.

The clinker 36 was taken from the outlet of the actual machine and cooled, and was placed on the lattice plates 20A, 20B and 20C by a layer height of 700 mm and about 80 kg. The air volume was adjusted so that the superficial velocity would be 1 m / s, depending on where the actual air volume was low. After the clinker 36 dropped for one hour, the clinker accumulated in the wind box 38 was taken out and its weight was measured.

The experimental results are summarized by the relative values with respect to the conventional lattice plate of FIG. 1 and shown in comparison with FIG.

Incidentally, in FIG. 6, the types of the lattice plates in the respective embodiments of FIGS. 1 to 5 are indicated by the symbols a to e. From this, it is understood that the present invention can reduce the falling amount of the clinker to 20% of the conventional amount (the conventional falling amount is 100% (R)).
And). The reason is the shape of the enlarged portion 13. That is, since the downstream surface of the enlarged portion 13 is tilted backward,
This is because the clinker in the enlarged portion 13 is easily discharged and the pressure due to the transfer of the clinker is not generated. When a pressure gauge was put in the trial and the surface pressure was measured, even if the lattice plate was moved, there was only a rise of about 20% of the pressure at rest.

Next, another embodiment of the lattice plate of the clinker cooler according to the present invention is shown in FIGS.

In FIG. 2, the upstream side of the enlarged portion 13 is also inclined by 30 degrees. In this example, the grid plate is movable and stationary, and in the movable grid plate, the clinker sometimes flows relatively in the opposite direction, which is more effective in this example.
The amount of clinker drop is the lowest in the experiment, as shown in Fig. 6.
5%.

In this example, the radius of curvature of the inlet of the nozzle 12 is set to 0.5 times the gap to reduce the pressure loss of the nozzle 12, and the length is set to 2.5 times the gap to prevent the entry of fine clinker. ing. Therefore, an experiment was conducted in which the aperture ratio of the nozzle was increased from 5% to 20%, but the drop amount of the clinker was only increased by 10%. If structurally allowed, the pressure loss at the nozzle inlet can be further reduced by further increasing the radius of curvature.

Further, although there is a problem that the manufacturing becomes a little difficult and the pressure loss increases, there is a possibility that the infiltration of the clinker can be further reduced by making the length of the gap longer.

Further, in the example of FIG. 2, a back surface flow path 19 is provided by the back surface plate 18, and air is made to flow downward from the front surface back surface nozzle 17 of the lattice plate. In the structure shown in FIG. 1, since air does not flow at the tip R of the lattice plate, the temperature of the lattice plate rises, while air is forced to flow and cooled. The cooling air is jetted downward from the tip nozzle 17 and is jetted to the clinker layer through the space between the lattice plate and the next lattice plate. At this time, the differential pressure of the nozzle 17 (= the pressure P of the cavity at the tip portion 1−the pressure P 2 of the nozzle outlet)
About 100 mmAq is secured so that air does not flow backward. Therefore, hot air or clinker does not flow backward from here. Since the opening of the nozzle 17 is larger than the opening of the nozzle 12, the clinker particles are effectively discharged even if they fall from the nozzle 12 to the back surface channel.

FIG. 3 eliminates the curved surface at the outlet of the enlarged portion 13 of FIG. Although it is easy to manufacture, the amount of fall is still 30% and the effect is small.

In FIG. 4, the enlarged portions 13 are provided in a dispersed manner, and the nozzle 12 is also opened on the side surface side of the opening. In this case, the drop amount was 40%.

FIG. 5 is a diagram in which the present invention is applied to the conventional example of FIG. The falling amount of the clinker was 60%.

As described above, the effect of the present invention was confirmed in any of the embodiments.

[0047]

According to the present invention, the clinker drop amount can be reduced by 40% or more at the same manufacturing cost as the conventional one.

Further, when the falling amount of the clinker is reduced, the conveyor for discharging the clinker can be made smaller, so that the cost of the entire cooler can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view and a sectional view showing an embodiment of a lattice plate of a clinker cooler according to the present invention.

FIG. 2 is a plan view and a cross-sectional view showing another embodiment of the lattice plate of the clinker cooler according to the present invention.

FIG. 3 is a plan view and a cross-sectional view showing another embodiment of the lattice plate of the clinker cooler according to the present invention.

FIG. 4 is a plan view and a cross-sectional view showing another embodiment of the lattice plate of the clinker cooler according to the present invention.

5A and 5B are a plan view and a cross-sectional view showing another embodiment of the lattice plate of the clinker cooler according to the present invention.

FIG. 6 is an explanatory diagram showing the effect of each embodiment of the present invention in comparison with a conventional example.

FIG. 7 is a side view showing the overall configuration of a clinker cooler.

FIG. 8 is a characteristic diagram showing the relationship between the amount of cooling air for cooling the clinker and the outlet temperature.

FIG. 9 is a plan view and a cross-sectional view showing the structure of an example of a lattice plate of a conventional clinker cooler.

FIG. 10 is a plan view and a cross-sectional view showing the structure of another example of the lattice plate of the conventional clinker cooler.

FIG. 11 is a plan view and a sectional view showing the structure of another example of the lattice plate of the conventional clinker cooler.

FIG. 12 is a sectional view schematically showing a falling state of a clinker on a lattice plate.

13 is a cross-sectional view taken along the line AA ′ in FIG.

FIG. 14 is an explanatory diagram showing the configuration of a test device for testing the technical effect of the lattice plate according to the present invention.

[Explanation of symbols]

 1 clinker cooler 2 fan 3 wind duct 4 wind box 5 lattice plate 6 outer wall 7 hot air duct 8 drive device 9 frame 10 kiln 11 clinker 12 nozzle 13 expanded portion 14 rib 17 tip back nozzle 18 back plate 19 back passage 30 container 32 blower 34 drive device 36 clinker 38 wind box A secondary air B tertiary air C mill air D exhaust

Front page continued (72) Inventor Akira Mochizuki 1-10-10 Isogo, Isogo-ku, Yokohama-shi, Kanagawa Babcock Hitachi Ltd. Yokohama Engineering Center (72) Inventor, Koji Wakasa 1-2 Isogo-ku, Isogo-ku, Yokohama, Kanagawa No. 10 Babcock Hitachi Ltd. Yokohama Engineering Center

Claims (5)

[Claims] 1. A lattice plate of a clinker cooler that cools air while transferring a high-temperature clinker, the jet plate of cold air comprising:
It has a nozzle for ejecting cold air at a high speed, and an expansion part for decelerating the air downstream thereof, and is configured to gently send the cool air from the expansion channel to a clinker moving on the upper surface of the expansion part. In the lattice plate, a lattice plate of a clinker cooler, characterized in that at least a surface of the enlarged portion which is on the downstream side when viewed from the direction of movement of the clinker is inclined in the direction of movement of the clinker. 2. The lattice plate of the clinker cooler according to claim 1, wherein no nozzle is arranged on the downstream side of at least the clinker in the moving direction of the enlarged portion. 3. The radius of curvature of the inlet portion of the nozzle is at least 0.5 times the gap, the length is 2.5 times the gap or more, and the opening area is 20% or less of the horizontal projected area of the lattice plate. The lattice plate of the clinker cooler according to claim 2, wherein 4. A flow passage is provided on the back surface of the lattice plate provided with the enlarged portion, and the nozzle has a nozzle for ejecting air downward at least from the tip portion of the lattice plate.
The lattice plate of the clinker cooler according to any one of 1 to 3. 5. A fan for supplying cooling air, a wind box for distributing the cooling air introduced from the fan to the lattice plate, and a lattice plate having openings for ejecting the cooling air to the high temperature clinker layer deposited on the upper surface. A clinker cooler that has the above-mentioned structure and cools while transferring the clinker layer by the reciprocating motion of the tip end surface of the lattice plate, wherein the lattice plate is the lattice plate according to any one of claims 1 to 4. Cooler.