JPS59176583A - Fluidizing baking furnace for powdered raw material - 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 a fluidized fluidized kiln for powder raw materials such as cement and alumina.

In a conventional spouted bed type fluidized firing furnace of this kind, for example, as shown in Fig. 1, the upward flow at the center of the fluidized bed furnace body α is fast, the downward flow near the wall is slow, and the flow is slow especially at the conical part. , a stagnation area C of the fluid medium is formed, resulting in stagnation of the flow and deterioration of the flow. In order to prevent this, that is, to prevent the formation of the stagnation zone C, the inclination angle θ of the conical portion should be made considerably larger than the angle of repose of the fluid medium. However, in case 9, the height of the entire fluidized firing furnace becomes too high, which is not preferable. Furthermore, since the amount of retention in the furnace is increased in the height direction, the layer thickness of the fluidized bed becomes large.Therefore, the air pressure of the fluidizing air must be made high, which has the disadvantage of increasing running costs.

The present invention was made in order to eliminate the above-mentioned drawbacks of the conventional fluidized fluidized kiln, and in other words, it is possible to reduce the running cost without increasing the overall height of the fluidized kiln. The object of the present invention is to provide a fluidized sintering furnace for powder raw materials that does not cause fluidity deterioration.

For this reason, the configuration of the present invention is such that the fluidized firing furnace body has a cross-sectional area of an appropriate size, and the fluidized firing furnace body is installed in the vicinity of the central bottom portion of the firing furnace body with an upper opening communicating with the fluidized furnace body to direct the jet gas to the firing body. A high-speed airflow tube that blows upward from the central bottom of the furnace body, and a large number of airflow tubes that are installed in parallel near the gas outlet level of this high-speed airflow tube to supply a low-speed airflow that forms a fluidized bed within the furnace body. It is characterized by being equipped with a diffuser pipe.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 6.

FIGS. 2 and 3 show a first embodiment of the present invention, which is an example of a fluidized fluidized kiln suitable for high-temperature firing of cement clinker.

In the same figure, ■ is the main body of the fluidized calcination furnace.

Reference numeral 2 denotes a high-velocity airflow tube, which is installed upright near the central bottom of the firing furnace main body 1 with an upper opening communicating with it, and is configured to blow jet gas upward from the central bottom of the firing furnace main body 1. It also serves as a primary classification tube. 3
is a low-speed airflow tube, which is provided in communication with the lower part of the high-speed airflow tube 2, and serves as a secondary classification tube.

Reference numeral 4 denotes aeration tubes, which are provided in large numbers in parallel near the gas outlet level of the high-speed airflow tube 2, and have a large number of ventilation holes in the lateral direction to form a low-speed airflow bed in the firing furnace body 1. It is designed to provide airflow. Further, as shown in FIG. 3, the diffuser pipe 4 is detachably (pulls out) attached to the firing furnace body 1. 5 is burner,
6 is an exhaust pipe, 7 is a raw material supply pipe, 8 is an aerodynamic valve,
9 is a jet part, ] 0 is a flowing part, 11 is a free board, 12
1 is an inert filling (does not melt even at high temperatures) filled in the lower part of the diffuser tube 4 to prevent bending of the diffuser tube 4; 13 is a clinker outlet; 14 is a residue outlet;
5 is a gas supply pipe that supplies gas to the high-speed airflow pipe 2;
6 is a gas supply pipe for supplying gas to the low-speed airflow pipe 3, and 17 shown in FIG. 3 is a gas supply pipe for supplying gas to the aeration pipe 4.

In the fluidized fluidized firing furnace for powder raw materials configured as shown in Figures 2 and 3, in the case of high-temperature firing of cement clinker, the central high-speed airflow pipe 2 (primary classification zone) has a target particle size for classification. The wind speed in the low-speed air flow pipe 3 (secondary classification zone) is set to the final velocity of , and the wind speed is set to the fluidization start speed of the target particle size for classification, to form a spouted bed in the jet section 9 of the fluidized fluidized furnace body 1.

On the other hand, the air diffuser 4 supplies enough air to maintain the flow of particles in the fluidized bed of the fluidized section 10 of the fluidized firing furnace main body 1,
The average superficial velocity in the fluidized bed of the total amount of air between the central high-speed air flow pipe 2, low-speed air flow pipe 3, and aeration pipe 4 is set to 2 to 3 meters per second, and fuel is blown from the burner 5 to start combustion. The temperature inside the fluidized bed was set at 1350 to 1400°C.
When cement raw materials are introduced from the raw material supply pipe 7 while the temperature is maintained at It becomes a binder and is granulated to become a cement clinker with a higher melting point, which undergoes fluid movement, and only 2 to 6 mm diameter particles are classified by the central high-speed airflow pipe 2 and low-speed airflow pipe 3, and the clinker The clinker is extracted as a mineral through the clinker outlet 13.

In this way, in the fluidized calcination furnace for powder raw materials shown in FIGS. 2 and 3, the jet section 9 transports particle groups upward through the high-speed air flow tube 2, which is provided in the center and also serves as a classification mechanism.
and a fluidized part 10 having a velocity sufficient to maintain the fluidization of particles around this, and therefore, it is possible to prevent deterioration of fluidization without increasing the height of the entire fluidized firing furnace. Therefore, a large amount of retention can be obtained with a low layer thickness, and the fluidizing air can be used at a low pressure, thereby reducing running costs. Further, a large number of air diffusers 4 are provided at the lower part of the flow section 10, and the air from the air diffusers 4 is used for flow. The lower part of the air diffuser pipe 4 is covered with a filler 12 to prevent the air diffuser pipe 4 from bending.Moreover, the air diffuser pipe 4 has a structure that takes into account the effects of thermal expansion and is removable. In case of periodic inspection etc., by pulling this out,
The residue in the fluidized furnace can be completely discharged.

FIG. 4 shows a second embodiment of the present invention, which corresponds to FIG. That is, in FIG. 3, the fluidized firing furnace main body 1 is cylindrical, whereas in FIG. 4, the only difference is that it is rectangular, and the rest are exactly the same.

FIG. 5 shows a third embodiment of the present invention, mainly showing the arrangement of the diffuser pipes 4. In FIG. In this embodiment, the diffuser tubes 4 are arranged at an angle α such that the side closer to the furnace wall of the firing furnace body 1 is higher.

By doing this, the particles and the like that have descended near the furnace wall can easily move to the center as shown by the arrow 18. Note that the other details are the same as those of the first embodiment.

FIG. 6 shows a fourth embodiment of the present invention, which corresponds to FIG. 5. That is, in this embodiment, the diffuser tubes 4 are arranged in a staggered manner in two stages, with the distance between them being wider than the particle diameter, and at an angle α. By doing this, as shown in Figure 5, it becomes easy to move the particles, etc. that have descended near the furnace wall to the center, and the particles can be easily discharged. However, as shown by arrow 19, its discharge becomes easy.

As described above, according to the present invention, it is possible to increase the size of the fluidized firing furnace without increasing the overall height, and it is possible to increase the residence time of the fluidized medium in the furnace. The formation of stagnation areas within the furnace is also eliminated. In addition, since the fluidized bed pressure can be lowered, the gas pressure for fluidization can be maintained at a lower pressure, and running costs can also be reduced.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional jet type fluidized firing furnace, Fig. 2 is a longitudinal sectional front view showing the first embodiment of the present invention, Fig. 3 is a cross-sectional plane taken along the cutting line A-A in Fig. 2. 4 is a sectional plan view showing a part of the second embodiment of the present invention, FIG. 5 is a longitudinal sectional front view showing a part of the third embodiment of the invention, and FIG. FIG. 1 is a vertical cross-sectional front view showing a part of the fourth embodiment of the present invention.
・Low speed airflow pipe, 4... Diffuser pipe, 5... Burner, 6.
... Exhaust pipe, 7... Raw material supply pipe, 8... Air valve, 9... Jet flow section, 10... Flow section, ]1...
・Free board, 12... Filling material, ] 3... Tarinka outlet, 14... Residue outlet, 1.5.16.
17... Gas supply pipe. (9) 4 ψ hunting J

Claims (1)

[Claims] 1. A fluidized furnace body having an appropriate cross-sectional area;
A high-speed airflow tube is installed near the central bottom of the firing furnace body with an upper opening in communication with the high-speed airflow tube, and spouts jet gas upward from the central bottom of the firing furnace body, and a gas outlet of the high-speed airflow tube. A fluidized firing furnace for powder raw materials, characterized in that it is equipped with a large number of diffuser tubes that are arranged in parallel near a level and supply a low-velocity airflow that forms a fluidized bed within the furnace main body.