JPH0341280Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is a method of heat exchange between gas flowing from bottom to top while swirling inside a vertical duct and powder injected into the vertical duct. In the vertical duct, for example, in the vertical duct section that performs heat exchange between the gas of the multi-stage cyclone cement preheating device and the cement raw material, the powder introduced into the vertical duct is dispersed in the gas. This invention relates to a powder dispersion device for dispersing powder.

[Prior Art] FIG. 1 is a schematic longitudinal sectional front view of a vertical duct section that performs heat exchange between gas and cement raw material in a conventionally known cement preheating device. In this figure, in general, cement raw material 3 introduced into a vertical duct 2 through a raw material chute 1 is given a swirling force by a cyclone 4 located below the vertical duct 2, and a gas 5 rises inside the duct 2. Heat exchange takes place while in contact with. This cement raw material 3
It was considered that the cement raw material 3 could not be sufficiently dispersed in the gas 5 in the charging method described above, and thus heat exchange between the cement raw material 3 and the gas 5 could not be carried out efficiently.

Therefore, in the past, a raw material dispersion plate 6 was placed approximately at the raw material chute 1 at the powder input port 8 so as to impede the flow of the cement raw material 3 introduced into the vertical duct 2 from the raw material chute 1 as shown in FIG. By installing the cement raw material 3 at a right angle, the dispersibility of the cement raw material 3 in the gas is increased and heat exchange is promoted.

[Problems to be solved by the invention] However, according to this method, the cement raw material 3 certainly collides with the raw material dispersion plate 6 and is scattered, and the dispersibility can be improved, but in terms of heat exchange, It has not yet reached a sufficient level of effectiveness. That is,
Although heat exchange is promoted by improving the dispersibility of the cement raw material 3 and increasing the effective heat transfer area, the inertial force that causes the cement raw material 3 to fall downward is weakened, so that the cement raw material 3 and gas 5
The time for heat exchange in countercurrent flow becomes shorter, making it impossible to improve heat exchange performance as a whole.

[Means for solving the problems] The present invention solves the problems of the conventional powder dispersion device consisting of a raw material dispersion plate as described above. Inside the vertical duct, heat exchange occurs between the gas flowing into the vertical duct and the powder introduced into the vertical duct from the powder inlet. The powder dispersion device is equipped with a rectangular flat powder dispersion plate extending downward from the part where the powder inlet is located, blocking the rotation so as not to be affected by the The present invention provides a powder dispersion device that disperses raw materials in a manner that promotes heat exchange between the powder and rising gas.

[Operation] The swirling force of the gas flowing in the vertical duct is suppressed by the powder dispersion plate. As a result, the absolute value of the velocity vector of the gas flow becomes smaller, and the force of the gas that tries to push the powder floating in the vertical duct upwards toward the inner circumferential wall of the vertical duct becomes weaker, causing the powder to flow from the powder inlet. Powder introduced into the vertical duct falls deeper inside the vertical duct by making use of the inertia it had when it was introduced into the vertical duct, and then rises inside the vertical duct again riding the gas flow. . Therefore, the countercurrent section where the flow directions of the raw material and the gas are opposite becomes longer, and the efficiency of heat exchange is further improved.

On the other hand, in this countercurrent section of the raw material and gas, the gas swirling and rising is trying to be changed from a swirling flow to a straight flow by the powder dispersion plate, that is, to be rectified, and the gas is flowing upward through the vertical duct. The powder inside is not pushed toward the inner wall surface of the duct due to the influence of the swirling flow, but is dispersed in the gas by diffusion by the gas flow. At this time, as described above, since the contact area between the powder and the gas due to countercurrent flow is lengthened, the powder is more effectively dispersed into the gas. and,
By dispersing the powder into the gas in this way, the effective heat transfer area between the raw material and the gas is increased, and the heat transfer rate is increased. Together with the improvement in the exchange rate, the heat exchange rate is further improved.

[Example] Next, an example of the present invention will be described in detail based on the drawings.

3A and 3B show the first embodiment of the present invention, FIG. 3A is a longitudinal sectional front view, and FIG. 3B is a sectional view taken along the line ˜ of FIG. 3A. be.

In this embodiment, as described above, the present invention is applied to a multi-stage cyclone cement preheating device, and the case where the powder is a cement raw material will be described.

In both figures, a cement raw material dispersion plate (hereinafter simply referred to as a raw material dispersion plate) 7 as a powder dispersion plate is
It is formed as a plate with a rectangular cross section, and extends inside the vertical duct 2 from the opening of the raw material chute 1 to the vertical duct 2, that is, near the powder inlet 8, directly below the vertical duct 2, It is attached perpendicularly to the inner wall surface of the vertical duct 2. In this case, as shown in FIG. 3B, when the vertical duct 2 is viewed in cross section, the raw material dispersion plate 7 is oriented toward the powder inlet 8 in the gas flow direction (indicated by arrow D in the figure). It is installed somewhat closer to the upstream side than the

By providing the raw material distribution plate 7 inside the vertical duct 2, the gas flowing from the cyclone 4 into the vertical duct 2 collides with the raw material distribution plate 7 and its swirling force is lost. The velocity vector of the flow is as shown in Fig. 4 A, B, and C when there is no raw material dispersion plate, or when the conventional dispersion plate 6 shown in Fig. 2 is installed. The current state changes from B to A, and the absolute value of the velocity vector becomes smaller. In Fig. 4 A, B, and C, A and B are the absolute velocity vectors of the present invention and when there is no raw material dispersion plate, and when a conventional dispersion plate as shown in Fig. 2 is provided, respectively. The values, A _t and B _t are
The tangential forces of A and B, A _v and B _v , respectively, are:
The vertical component forces of A and B are shown respectively. FIG. 4A is a schematic diagram showing vertical component forces A _v and B _v of velocity vectors A and B, and FIG. 4B is a schematic diagram showing tangential component forces of velocity vectors A and B. C
is a graph showing the absolute values of the velocity vectors of A and B.

As shown in Figure 4A, the vertical component force is A _v
= B _v , and the present invention and the conventional one are equal, but regarding the tangential component force, A _t of the present invention is extremely smaller than B _t of the conventional case, and therefore, the absolute value of the velocity vector is As shown in the graph in Figure 4C, the speed changes from B to A, which is the state when there is no raw material dispersion plate and the state when the conventional dispersion plate 6 shown in Fig. 2 is installed. The absolute value of the vector becomes smaller.

Therefore, the force of the gas that tries to push the raw material floating in the vertical duct 2 upward to the inner peripheral wall surface of the vertical duct 2 is weakened, and the raw material flows from the raw material chute 1 through the powder inlet 8 into the vertical duct 2. The input material takes advantage of the inertial force that it has when it is input into the vertical duct 2, and it is more effective than when no dispersion plate is installed or when a conventional dispersion plate is installed as shown in Figure 2. The gas also falls deeper inside the vertical duct 2 and rises inside the vertical duct 2 again riding the gas flow. Heat exchange between the raw material and the gas is mainly performed in a countercurrent section where the flow directions of the raw material and the gas are opposite to each other.

In this way, the raw material distribution plate 7 increases the distance over which the raw material and gas exchange heat while contacting each other in countercurrent flow in the vertical duct 2, that is, the time for heat exchange becomes longer, and the efficiency of heat exchange is improved. do.

On the other hand, the dispersion of the raw material into the gas is not due to the scattering effect caused by the collision of the raw material with the dispersion plate 6 as in the conventional type shown in FIG. It is done by twisting.
That is, the raw material dispersion plate 7 works to rectify the swirling flow (the effect of changing the gas flow in the vertical duct 2 from a swirling flow to a straight flow), and the raw material in the vertical duct 2 is It is dispersed in the gas without being pushed toward the inner wall surface of the vertical duct 2 due to the influence of the swirling flow.

At this time, as described above, since the contact section between the raw material and the gas due to countercurrent flow is lengthened, the dispersion effect of the raw material is further improved. Such dispersion of the raw material into the gas increases the effective heat transfer area between the raw material and the gas, increases the heat transfer rate, and improves the heat exchange rate due to the deeper fall of the raw material into the gas as described above. Together with this, the heat exchange efficiency is further improved.

Next, another embodiment of the present invention will be described.

5A and 5B show a second embodiment of the present invention, FIG. 5A is a longitudinal sectional front view, and FIG. 5B is a
is a sectional view taken along the line V-V in FIG. 5A.

In both figures, the raw material distribution plate 9 has a rectangular cross section that is tilted obliquely rather than parallel to the axial direction of the vertical duct 2 and is provided along the inner circumferential wall surface of the vertical duct 2. has been done. The direction in which the raw material distribution plate 9 is tilted is such that the swirling flow can collide with the raw material distribution plate 9 at a substantially right angle.

By forming the raw material distribution plate in this way, swirling gas is forcibly blocked,
The effect of allowing the raw material to fall deeper and preventing the raw material from being pushed toward the inner wall surface of the vertical duct 2 as described in the first embodiment is further enhanced.

Therefore, the dispersion effect of the raw material into the gas can be further increased, and the heat exchange rate can be further increased.

Note that there are no particular limitations on the number and size of the raw material dispersion plates 7, 9 to be attached, or their positions relative to the powder inlet 8, as explained above. The bigger the
Further, the lower the powder inlet 8 is located, the greater the effect of dispersing the cement raw material.

Furthermore, in this example, a case was shown in which the powder dispersion plate of the present invention was installed in a vertical duct in a cement preheating device, but it goes without saying that the present invention can be applied not only to this case but also to other similar devices. stomach.

[Effects of the invention] As described above, since the powder dispersion device of the present invention has the configuration described in the claims for utility model registration, powder such as cement raw material is placed in the vertical duct and the rising gas is dispersed. Since it can be allowed to fall deeper into the interior and be dispersed in the gas, the heat exchange efficiency between the raw material and the gas can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic longitudinal sectional front view showing a vertical duct section for heat exchange between gas and cement raw material in a conventionally known cement preheating device; Fig. 2 is a longitudinal sectional front view showing a conventional raw material distribution plate; 3 shows the first embodiment of the present invention, FIG. 3A is a longitudinal sectional front view, FIG. 3B is a sectional view taken along the line ˜ of FIG. 3A, and FIG. This shows a comparison of gas velocity vectors. Figure 4A is a schematic diagram showing the vertical component of the velocity vector, Figure 4B is a schematic diagram showing the tangential component of the velocity vector, and Figure 4C is a diagram showing the tangential component of the velocity vector.
5 is a graph showing the absolute value of the velocity vector, FIG. 5 shows a second embodiment of the present invention, FIG. 5A is a longitudinal front view, and FIG. It is a diagram. 1... Raw material chute, 2... Vertical duct, 3...
...Cement raw material, 4...Cyclone, 5...Gas, 6,7,9...Raw material (powder) dispersion plate, 8...
Raw material (powder) input port, A, B...speed vector.

Claims (1)

[Scope of utility model registration request] The powder introduced into the vertical duct exchanges heat with the gas flowing from bottom to top while swirling inside the vertical duct, and the powder is introduced into the duct from the powder inlet. In a vertical duct, a rectangular flat powder dispersion plate is installed that blocks the swirling so that the powder is not affected by the swirling and extends downward from the part where the powder inlet is located. Powder dispersion equipment.