JPS60635Y2 - Fluidized bed kiln for powder raw materials - Google Patents

Description

[Detailed description of the invention] The invention relates to a fluidized bed firing furnace for powder raw materials.
Specifically, the present invention relates to a kiln for firing powder raw materials such as cement and alumina using a fluidized bed instead of a rotary kiln.

Rotary kilns have been used for a long time as furnaces for firing cement raw materials, but rotary kilns are relatively small in diameter and are long, heavy rotating bodies, so they have been replaced with fluidized-bed furnaces. It is known that there are numerous benefits if this can be done.

However, in general, in a fluidized bed, air and fuel are incompletely mixed,
The air ratio needs to be at least 1.3, and it is difficult to raise the temperature to a high temperature at which clinker can be fired and maintain that high temperature.

In order to improve the mixing of air and fuel in the fluidized bed, this invention creates a diluted fluidized bed in the lower part of the fluidized bed to increase the oxygen utilization rate, make it easier to raise the temperature of the fluidized bed, and A firing burner is installed to form a high-temperature firing zone there to promote the formation of clinker, and the raw material to be fired is supplied to the thin fluidized bed to prevent it from flying out into the freeboard. , one embodiment thereof will be described with reference to the drawings.

In the drawings, reference numeral 1 denotes a fluidized bed firing furnace, which has, in order from bottom to top, a lean fluidized bed forming section 2, a dense fluidized bed forming section 3, and a freeboard section 4.

That is, from bottom to top, the first inverted conical part 5 and the first cylindrical part 6 form the lean fluidized bed forming part 2, the second inverted conical part 7 and the second cylindrical part 8 form the dense fluidized bed forming part 3, The third inverted conical part 9 and the third cylindrical part 10 constitute the freeboard part 4, and the cross-sectional area and diameter of each part are the smallest in the dilute fluidized bed forming part 2, The dense fluidized bed forming section 3 is in the middle, and the freeboard section 4 is the largest.

The dilute fluidized bed forming section 2 is also provided with a firing burner 11 and a powder raw material supply port 12 , and a compressed air pipe 14 is connected to the raw material chute 13 in the middle of the raw material chute 13 connected to the supply port 12 . connected towards the

In addition, 15 is a furnace top wall, 16 is an exhaust gas outlet, and 17 is a combustion air duct connected to the lean fluidized bed forming section 2.

In the spouted bed fluidized bed kiln 1 configured as described above, powder raw materials such as preheated cement raw materials or cement raw materials calcined after preheating are passed from the raw material chute 13 through the raw material supply port 12 in a dilute flow state. It is introduced into the layer forming section 2.

At this time, a compressed air pipe 14 is placed in the middle of the raw material chute 13.
Therefore, the powder raw material is charged into the diluted fluidized bed forming section 2 by compressed air.

In this diluted fluidized bed formation section 2, the cross-sectional area is relatively small, so the rising wind speed of the fluidized bed is small, and the existence of particles is diluted, so that the oxygen utilization rate is increased and the temperature can be easily raised. It is.

The raw material in the dilute fluidized bed forming section 2 moves to the dense fluidized bed forming section 7 where it is fired and becomes clinker, and when it grows and becomes large, it descends due to its own weight and moves to the dilute fluidized bed forming section 2.
It is completely fired at , and then sent to a clinker cooler as shown by arrow 18 .

Note that the exhaust gas is sent to a calcining furnace or the like through the exhaust gas outlet 16, but since this outlet 16 is not located in the center of the furnace top wall 15, but is eccentrically provided toward the end, the to-be-fired material scattered on the freeboard portion 4 The proportion of substances being discharged along with them is reduced.

Further, in the above embodiment, the powder raw material supply port 12 was provided only in the dilute fluidized bed forming section 2, but
A similar supply port may also be provided for supplying the powder raw material to both parts 2 and 3.

As described above, the present invention has, in order from bottom to top, a dilute fluidized bed forming section, a dense fluidized bed forming section, and a freeboard section, and the lean fluidized bed forming section is the lowest part of the fluidized bed. Since the combustion chamber is equipped with a firing burner, it increases the utilization rate of oxygen during combustion, makes it easier to raise the temperature of the fluidized bed, and makes the lean fluidized bed formation part a high temperature combustion zone, which promotes the formation of clinker. Since the dilute fluidized bed forming section is equipped with a powder raw material supply port, the powder raw material fed into the fluidized bed from the supply port does not immediately reach the freeboard section, and is considerably prevented from flying out into the freeboard section. Ru.

[Brief explanation of the drawing]

The figure is a sectional elevational view showing one embodiment of the present invention. 1... Fluidized bed firing furnace 2... Lean fluidized bed forming section, 3... Dense fluidized bed forming section, 4...
・・・Free board part, 11... Firing burner,
12...Powder raw material supply port.

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. , wherein the dense fluidized bed forming section is in the middle and the freeboard section is the largest, and the lean fluidized bed forming section is equipped with a firing burner and a powder raw material supply port. Fluidized bed kiln.