JPS60637Y2 - Spouted bed type fluidized furnace - Google Patents

Description

[Detailed description of the invention] The present invention relates to a spouted bed type fluidized calcination furnace, and more specifically, to a calcination furnace that uses a fluidized bed to sinter powder raw materials such as cement and alumina without using a rotary kiln. It is something.

Rotary kilns have been used for a long time to kiln raw materials for cement, but rotary kilns have a relatively large diameter and are long, heavy rotating bodies, so they will be replaced with fluidized kilns. It is known that there are a number of benefits if this can be done.

However, in order to granulate clinker that does not cause dusting (change in form and become powder at room temperature) in a fluidized bed where the residence time of powder raw materials is shorter than that in a rotary kiln, it is necessary to react at high temperatures. Moreover, bubbles are likely to occur in a fluidized bed, and the oxygen in the bubbles passes through the fluidized bed without contributing to combustion, leading to an increase in flying particles, and even if the amount of fuel supplied is increased. , the temperature of the fluidized bed does not rise, only the temperature of the free board rises, which has the disadvantage of making it difficult to raise the temperature within the bed.

In other words, the reason why it is difficult to raise the temperature in the bed is that the combustion air and fuel are not sufficiently mixed in the bed, so unburned fuel is not used for combustion in the fluidized bed and is left in the freeboard. This is because it is used for combustion.

Therefore, in the present invention, a lean fluidized bed section is formed by reducing the cross-sectional area at the bottom of the fluidized bed, and the combustion section is concentrated in this lean fluidized bed section to increase combustion efficiency and increase the temperature within the fluidized bed. One embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, a is a spouted bed type fluidized firing furnace, which includes, in order from bottom to top, a lean fluidized bed forming section 1, a dense fluidized bed forming section 2,
The relationship between the cross-sectional areas (relationships between inner diameters) of each of the above-mentioned parts is such that the dilute fluidized bed forming part 1 is the smallest and the dense fluidized bed forming part 2 is the middle. , the freeboard section 3 is the largest.

As shown in an enlarged view in FIG. 3, a secondary air duct 4 is connected to the diluted fluidized bed forming section 1, and the fuel for firing the powder raw material is preliminarily mixed with the secondary air. The secondary air duct 4 is installed at a position where the burner 5 is retreated from the inner surface 6 of the furnace wall of the lean fluidized bed forming section 1 (a position far from the inside of the furnace) so that it will be introduced into the lean fluidized bed forming section 1 later.
The secondary air passage is provided in communication with the secondary air passage.

Further, as shown in FIG. 2, in order to uniformly spray fuel into the lean fluidized bed forming section 1, a plurality of secondary air ducts 4 and burners 5 are arranged eccentrically with respect to the center of the furnace. ing.

Additionally, numeral 7 shown in Figure 1 is a chute for supplying powder raw materials such as cement raw materials.

In the spouted bed type fluidized firing furnace a configured as described above, the burner 5 is installed at a position that is set back from the inner surface 6 of the furnace wall, and the burner 5 is installed at a position that is set back from the inner surface 6 of the furnace wall, and after the burner 5 has been preliminarily mixed with the secondary air in the secondary air duct 4. Since the fuel is introduced into the lean fluidized bed forming section 1, in other words, the fuel and secondary air are sufficiently mixed, so that a good flow rate is achieved in the lean fluidized bed forming section 1 and the dense fluidized bed forming section 2 directly above it. Combustion is obtained and therefore the lean fluidized bed temperature and the increase in the rich fluidized bed temperature are easily carried out so that the powder raw material can be calcined into good quality clinker.

In this way, in the spouted bed type fluidized firing furnace of the present invention,
The combustion part is concentrated in the diluted fluidized bed forming part at the bottom.
Moreover, since the burner is set back from the inner surface of the furnace wall so that the fuel is mixed with the secondary air before being introduced into the lean fluidized bed formation section, good combustion can be achieved on both flow surfaces. In addition, since the distance from the fuel inlet to the freeboard is maximum and the combustion time is long, the powder raw material can be sufficiently fired and high quality clinker can be obtained.

Moreover, since the high-temperature heating zone is formed in the center of the fluidized bed,
Fusion to the furnace wall can be reduced.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a cross-sectional front view, Fig. 2 is a cross-sectional plan view taken along the cutting line A-A in Fig. 1, and Fig. 3 is a thin fluidized bed forming part. It is an enlarged sectional front view of. a...Spouted bed type fluidized firing furnace, 1...Leak fluidized bed forming section, 2...Dense fluidized bed forming section, 3.
...Freeboard part, 4...Secondary air duct, 5...Burner, 6...Furnace wall inner surface, 7...Powder raw material supply chute.

Claims (1)

[Scope of utility model registration request] It has a dilute fluidized bed forming part, a dense fluidized bed forming part, and a freeboard part in order from the bottom to the top, and the relation of the cross-sectional area of each part is such that the dilute fluidized bed forming part is the smallest. , the dense fluidized bed forming section is in the middle and the freeboard section is the largest, and a secondary air duct is connected to the lean fluidized bed forming section, and the fuel for firing the powder raw material is supplied to the secondary air. The burner is connected to the secondary air passage of the secondary air duct at a position recessed from the inner surface of the furnace wall of the lean fluidized bed forming section so that the burner is introduced into the lean fluidized bed forming section after converging and mixing in advance. A spouted bed type fluidized firing furnace, characterized in that it is installed in a.