JPH0728557Y2 - Vertical firing furnace - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a vertical firing furnace for firing an object to be fired, such as limestone or dolomite, using solid fuel, and more specifically, it includes a volatile component. The present invention relates to a vertical firing furnace that enables efficient firing even with solid fuel such as coal.

[Conventional technology]

As is well known in the art, in this type of vertical firing furnace, as shown in FIG. 5, limestone (hereinafter, the object to be fired is described as limestone) and solid fuel from the top of the furnace body are used. The coal is charged into the furnace, and a pre-tropical zone A, a calcination zone B, and a cooling zone C are formed in this order from the top in the furnace, and quick lime, which is a calcined product calcined from the furnace bottom, is discharged as a product. In the firing zone B, limestone (so-called calcium carbonate) is pyrolyzed in the oxidizing atmosphere of solid fuel such as coal under the necessary temperature conditions to form quicklime (so-called calcium oxide). In pre-tropical zone A and firing zone B,
The solid fuel is present between particles of limestone, and the limestone that has been preheated to a predetermined temperature by the combustion gas in the firing zone B in the pre-tropical zone A is burned in the firing zone B by burning the solid fuel. Then, the calcined quicklime is cooled in the cooling zone C by the combustion air supplied from the bottom of the furnace body, and then discharged.

[Problems to be solved by the device]

In a vertical firing furnace having such a firing mechanism, when solid fuel such as anthracite or coke having a low volatile content is used, a predetermined action is performed in the pretropical zone A or the firing zone B to obtain a predetermined decarboxylation degree. Although it is possible to obtain a high-quality calcined product having, for example, the following problems when using a solid fuel containing a large amount of volatile matter.

That is, since the volatilization temperature is generally lower than the atmospheric gas temperature in the pretropical zone A, the volatile components in the fuel are volatilized in the pretropical zone A and burned or unburned and discharged outside the furnace. Such behavior of the fuel not only causes a loss of combustion heat of the fuel but also causes an increase in exhaust gas temperature and instability of the formation position of the firing zone B, that is, the pre-tropical zone A and the firing zone B. Each of the initial actions in (2) above is not stably performed, and a product to be fired having a poor product quality is discharged from the bottom of the furnace, which seriously hinders the operation of the baking furnace. The volatilization of volatile matter cannot be controlled manually by controlling the amount of combustion air supplied from the bottom of the furnace. As a result, solid fuels with low volatile content must be selected.

The present invention has been made in view of such problems, and it is a vertical type that can obtain a good quality fired product by performing a predetermined action in the pre-tropical zone or in the firing zone even if a solid fuel with a high volatile content is used. It is intended to provide a firing furnace.

[Means for Solving the Problems]

In order to achieve the above object, the vertical firing furnace of the present invention has a vertical firing furnace in which a material to be fired is supplied from the upper portion of the furnace body, fired between solid fuel and the fired material and taken out from the lower portion of the furnace body. Type firing furnace, a plurality of fuel supply pipes for introducing the solid fuel into the furnace are attached to the furnace body with their fuel outlets facing the firing zone, and the fuel supply pipes are attached to the inner and outer pipes. And an inner pipe is formed as a fuel supply passage and an air supply passage is formed between the inner pipe and the outer pipe, and an air discharge port is provided near the fuel discharge port. The exhaust port and the air exhaust port are movably attached to the furnace body so that the vertical positions thereof can be adjusted, and a radially extending portion is formed at the lower end portion of the outer pipe of the fuel supply pipe to form an inner portion. A space where solid fuel particles can fall is formed in the raw material packed bed below the lower opening of the pipe. It was constructed in.

[Operation] By installing a plurality of fuel supply pipes for introducing solid fuel into the furnace, with their fuel outlets facing the firing zone, and installing them in the furnace body, the firing zone as well as the preheating zone can be placed in a stable position. In this firing zone, the solid fuel fed from the fuel supply pipe to the inside of the furnace is discharged from the fuel discharge port to the outside of the pipe, and this solid fuel is mixed with the burning object that is preheated from the pre-tropical zone and descends. Then, the solid fuel is burned to burn the object to be fired. At this time, even if the solid fuel contains volatile matter, most of the volatile matter is burned in the firing zone, so it is unlikely to burn in the pre-tropical zone as in the past, and the initial action in the pre-tropical zone and the firing zone is small. Definitely done. Further, the combustion heat is surely used for firing. By providing a plurality of fuel supply pipes so that they are arranged substantially evenly with respect to the cross section of the furnace body, the temperature distribution in the firing zone becomes uniform, and firing is performed uniformly. Therefore, a good quality fired product can be obtained.

Further, the fuel supply pipe is formed of an inner pipe and an outer pipe, the inner pipe is used as a fuel supply passage, and the space between the inner pipe and the outer pipe is formed as an air supply passage, and the air discharge port is located near the fuel discharge port. With this structure, the fuel supply pipe is cooled by the air and endurance against high temperature is given, and the cooled air is jetted from the air exhaust port near the fuel exhaust port to the firing zone. As a result, the combustion of the volatile matter generated from the solid fuel is optimally controlled. In addition, it is more preferable to arbitrarily adjust the air amount.

Since the fuel supply pipe is movably attached to the furnace body so that the vertical positions of the fuel discharge port and the air discharge port can be adjusted, the level of the firing zone is adjusted to the optimum position. Can be set by
It is possible to easily cope with the difference in the burning rate depending on the type of fuel and the difference in the burning level depending on the type of the material to be fired.

Furthermore, since the solid fuel is dropped into the space formed in the raw material filling layer below the lower end opening of the fuel supply pipe, the solid fuel is smoothly mixed with the object to be fired and the object to be fired is evenly fired.

From the above, according to the present invention, it is possible to always set the optimum firing zone level even for the difference in the burning rate depending on the type of fuel and the difference in the burning level depending on the type of the material to be burned, and to ensure that the fuel is reliable. In addition, since the particles to be fired are mixed between the particles, it is possible to obtain an extremely high quality fired product with less unevenness in firing.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is a view in which the continuous packed bed inside the furnace of the vertical firing apparatus of the present invention is classified according to function in correspondence with FIG. 5, and FIG. 2 is a schematic view showing the entire firing furnace of the present invention. FIG.

In these figures, a furnace body 1 is formed upright on a foundation 1a and is formed into a vertical cylindrical shape, and an inner refractory brick 2 is provided on the inner peripheral surface thereof. At the center of the top of the furnace body 1, a supply device 5 for the limestone 3, which is the object to be fired, is attached, and at the bottom of the furnace body 1, a product discharge device 6 is rotatably provided. A product discharge chute 7 is provided below the product discharge device 6. Reference numeral 7a is an inlet for combustion air provided in the product discharge chute 7, and 12 is an exhaust gas outlet.

A fuel supply pipe 10 is attached to the top of the furnace body 1 in a state of being hung from the top of the furnace body 1.
Solid fuel such as coal is supplied into the furnace from 10. The fuel supply pipe 10 is attached so that the fuel discharge port 10c formed at the lower end thereof is located above the firing zone B. A plurality of fuel supply pipes 10 are provided, but in FIG.
The book shows. It is desirable to install a plurality of these so that they are evenly distributed in the cross section of the furnace, for example, by installing them at equal intervals in the circumferential direction.

The fuel supply pipe 10 is formed of an inner pipe 10a through which fuel such as coal passes, and an outer pipe 10b concentrically attached to the outside of the inner pipe 10a, and air is provided between the inner pipe 10a and the outer pipe 10b. A passage 11 is formed. As shown in detail in FIG. 3, the lower end of the fuel supply pipe 10 is protected by a refractory brick 10d such as castable around the lower end of the inner pipe 10a to protect the inner pipe 10a from the high temperature atmosphere inside the furnace. ing. A radially projecting portion 10e is formed at the lower end of the outer pipe 10b, and an air discharge port 11a is formed between the outer pipe 10b and the refractory brick 10d around the lower end of the inner pipe 10a. The lower end 10f of the projecting portion 10e is the refractory brick 10d.
The lower end 10f of the limestone 3 which is the object to be fired forms an inverted conical space 13 as shown by the angle of repose. The limestone 3 descends in the firing zone B while maintaining this space 13. Coal easily falls into the space 13 from the supply port 10c and is supplied into the limestone 3 to be mixed.

A fuel supply device 14 also serving as an air seal is attached to the inner pipe 10a above the fuel supply pipe 10, and an air supply port 11b is provided above the outer pipe 10b.

Next, based on FIG. 4, the fuel supply pipe in the upper part of the furnace body 1
The mounting mode of the limestone supply device 10 and the limestone supply device 5 will be described in more detail.

A limestone supply device 5 is located at the center of the top of the furnace body 1. This supply device 5 is attached to a support 5e and has a chute in which a double damper 5d is openably and closably incorporated in an upper bent portion.
5a, and a rotary chute 5b fixedly attached to a rotary shaft 5c provided vertically through the chute 5a in the lower part of the chute 5a. The rotating shaft 5c
Is rotated by a drive device 19 including a motor and a speed reducer.

A plurality of fuel supply pipes are provided around the outside of the limestone supply device 5.
10, the inner pipe 10a and the outer pipe 10b of each fuel supply pipe 10 are integrally attached, and the fuel supply pipe 10 is supported by a supply pipe support member 15. This supply pipe support member
Reference numeral 15 denotes an annular center member 15a slidably fitted in the vertical direction on the outer surface of the support base 5e of the limestone supply chute 5a, an annular outer member 15b fixed to the periphery thereof, and this outer member 15b and a furnace. A pantograph-type supply pipe elevating / lowering device 15c properly arranged in the circumferential direction between the main body 1 and the main body 1.
It consists of and. A driving device such as a cylinder (not shown) is attached to the pantograph type supply pipe lifting device 15c. The outer pipe 10b of the fuel supply pipe 10 is fixed to the outer peripheral edge of the annular outer member 15b. A bellows that is vertically expandable and contractable is provided between a penetrating portion between the outer pipe 10b of the fuel supply pipe 10 and the furnace body 1 and a fixed portion of the outer pipe 10b of the fuel supply pipe 10 at the outer peripheral edge of the annular outer member 15b. It is connected by 16 and the gas inside the furnace is sealed. Also, the inner pipe 10
A fuel supplier 14 also serving as an air seal is attached to the upper portion of a while being supported by a fixed portion 18.
Between the lower flange of 14 and the upper flange of the inner pipe 10a,
Bellows 17 with flanges on both ends that can be expanded and contracted vertically
The inside of the bellows 17 is slidably fitted from the upper flange into the lower inner tube 10a.
0g is installed.

On the other hand, the upper end of the outer pipe 10b of each fuel supply pipe 10 is bent toward the center of the furnace body 1, and the air supply port 11b at the end is surrounded by the ring around the support 5e. It is connected to an air header 16 formed from a tube.

By configuring the fuel supply pipe 10 in this manner, if the supply pipe lifting device 15c is driven in the vertical direction, all the fuel supply pipes 10 will be integrated with the supply pipe support member 15 and the air header 16 in the vertical direction. Moving.

The supply pipe elevating / lowering device 15c is configured by arranging the cylinder in the vertical direction instead of the pantograph type, and for example, attaching the piston rod to the annular outer member 15b and attaching the cylinder body to the top of the furnace body 1. You can also do it.

The operation of the vertical firing furnace configured as above will be described.

When the rotary shaft driving device 19 of the limestone supply device 5 is driven to rotate the rotary chute 5b and the limestone 3 which is the object to be fired is supplied to the chute 5a, the limestone 3 is alternately opened and closed by the double damper 5d. It is guided to the rotary chute 5b and is uniformly supplied into the furnace by the rotation of the rotary chute 5b.

On the other hand, the lime containing volatile matter that is a solid fuel is air-sealed by the fuel supply device 14 of each of the fuel supply pipes 10 provided with a plurality of short pipes 10g inside the inner pipe 10a of the fuel supply pipe 10.
And is discharged into the furnace from the fuel discharge port 10c at the lower end thereof. At this time, in this discharge part, the protrusion 10e formed at the lower end of the outer tube 10b and the space 13 formed by the action of the repose angle of the limestone 3 are easily discharged and smoothly mixed into the limestone 3. To be done. Therefore, the generating action with less unevenness of firing is smoothly performed. Further, air is introduced from the air header 16 into the outer pipe 10b of each fuel supply pipe 10, this air passes through the air passage 11 between the inner pipe 10a and the outer pipe 10b, and between the inner pipe 10a and Cool the outer tube 10b. In addition,
The temperature of the firing zone B is as high as 750 to 1300 ° C., and the fuel supply pipe 10 is also exposed to this high temperature atmosphere.
The fuel supply pipe 10 is cooled by passing air through 11,
Durability is imparted to high temperatures, and the material can be made inexpensive. Especially its inner tube
This effect is remarkable in 10a. This cooled air is discharged into the furnace from the air discharge port 11a at the lower end of the fuel supply pipe 10 and used as a part of combustion air. And this fuel supply pipe
A firing zone B is stably formed below the lower end portion of 10, and a pretropical zone A is formed above the firing zone B. Further, a cooling zone C is formed below the firing zone B.

In the firing zone B, the air supplied from the combustion air inlet 7a at the bottom of the furnace and cooled through the cooling zone C to cool the fired material is mainly used to burn the coal fed from the fuel supply pipe 10. The limestone preheated in the pretropical zone A is used for calcination in the calcination zone B, and the air discharged from the discharge port 11a through the air passage 11 of the fuel supply pipe 10 into the furnace is also used for combustion. Used as part of the air. The air supply amount is adjusted by a damper (not shown) or a valve (not shown) attached to the air header 16 so that the burning rate of volatile matter in the coal can be adjusted to prevent uneven burning and deterioration of quality of the object to be fired. Is adjustable so that deterioration of product quality due to combustion of volatile matter having a high burning rate can be prevented and the quality can be stabilized.

The quicklime, which is a fired product fired in the firing zone B, descends into the cooling zone C and is cooled, and by the product discharge device 6 at the bottom of the furnace,
A predetermined amount is discharged from the chute 7 to the outside of the furnace.

The level of the firing zone B is the fuel discharge port at the lower end of the fuel supply pipe 10.
Supply pipe lifting device 1 provided at the top of the furnace body 1 with a level of 10c
By adjusting with 5c, it can be easily performed, and the formation level of the firing zone B can be set to the optimum position according to the properties of the fuel and the properties of the object to be fired, and a product with stable quality can be obtained. . For example, when using a fuel with a high burning rate or when using a fuel containing a larger amount of volatile matter, the fuel supply pipe 10 is lowered to lower the level of the combustion zone B so that the exhaust gas is discharged from the exhaust gas outlet 12. The exhaust gas temperature is adjusted to a predetermined temperature, and the firing degree is adjusted to be uniform. Of course, even when the type of fuel is changed, the optimum level of the firing zone B according to the burnup of the fuel can be easily adjusted, and a product with stable quality can be obtained.

In addition, in the present embodiment, a case is shown in which all of the plurality of fuel supply pipes 10 are configured to move up and down integrally, but this is the case where individual lifting devices are attached to the individual fuel supply pipes 10, respectively. It may be independently movable up and down.

Further, although the fuel supply pipe 10 is provided vertically downward from the top of the furnace body 1, this shows that a plurality of fuel supply pipes are inclined from the side wall of the furnace body 1 and the The outlet may be provided so as to face the firing zone.

[Effect of device]

As described above in detail, the present invention has the following excellent effects.

Since the solid fuel that is uniformly discharged into the furnace from the fuel outlets at the bottom of the multiple fuel supply pipes is burned at a position below the fuel outlets, the firing zone is formed at a stable position and volatilizes into solid fuel. Even if it contains a small amount, it does not burn like before in the pre-tropical zone, the temperature distribution is uniform in the combustion zone, and efficient firing is performed, and the initial action in the pre-tropical zone and the firing zone is reliably performed. .

Therefore, a good quality fired product can be obtained.

Further, since the fuel supply pipe is cooled by air, durability against high temperature is imparted, and the fuel supply pipe can be made of an inexpensive material having low heat resistance. Then, by jetting this cooled air from the air outlet near the fuel outlet to the firing zone, it is possible to optimally control the combustion of the volatile components generated from the solid fuel and stabilize the product quality. it can.

Since the fuel supply pipe is attached so as to be movable in the vertical direction, the level of the burning zone can be adjusted and set to the optimum position, and the burning speed difference due to the type of fuel and the burning target It is possible to easily deal with a difference in combustion level due to a difference in type, and a stable product can be obtained.

Further, since the solid fuel is dropped into the space formed in the raw material filling layer below the lower end opening of the fuel supply pipe, the solid fuel is smoothly mixed with the object to be fired, and the object to be fired is evenly fired. .

As described above, in the present invention, it is possible to always set the optimum firing zone level even for the difference in the burning rate depending on the type of fuel and the difference in the firing level depending on the type of the material to be fired, and Since it can be reliably mixed between the particles to be fired, there is a practical effect that a fired product of extremely good quality in which firing unevenness is constantly reduced can be obtained.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention. FIG. 1 is a view functionally showing a vertical firing furnace, and FIG. 2 is a schematic vertical section showing the entire vertical firing furnace. Fig. 3 is an enlarged vertical cross-sectional view showing the lower end of the fuel supply pipe, Fig. 4 is a vertical cross-sectional view showing the detailed structure of the furnace top, and Fig. 5 is a conventional vertical shaft corresponding to Fig. 1. It is a functional display diagram of a mold firing furnace. 1 ... Furnace body, 3 ... Limestone (material to be fired), 5 ... Limestone supply device, 6 ... Product discharge device, 7 ... Product discharge chute, 7a ... Combustion air inlet, 10 ... Fuel Supply pipe, 10
a …… Inner tube, 10b …… Outer tube, 10c …… Fuel outlet, 11 ……
Air passage, 11a ... Air discharge port, 15 ... Fuel supply pipe support member, 15a ... Center member, 15b ... Outside member, 15c ... Supply pipe lifting device, A ... Pre-tropical zone, B ... Firing zone , C ... Cooling zone.

Claims (1)

[Scope of utility model registration request] 1. A vertical firing furnace in which an object to be fired is supplied from an upper portion of a furnace body and fired between the solid fuel and the solid fuel so that the fired material is taken out from a lower portion of the furnace body. A plurality of fuel supply pipes to be introduced are installed with the fuel discharge ports facing the firing zone and attached to the furnace body. The fuel supply pipes are formed from an inner pipe and an outer pipe, and the inner pipe serves as a fuel supply passage. An air supply passage is formed between the pipe and the outer pipe, the air discharge port is provided near the fuel discharge port, and the fuel supply pipe is arranged so that the fuel discharge port and the air discharge port are vertically positioned. It is movably attached to the furnace body so as to be adjustable, and a radially extending portion is formed at the lower end portion of the outer pipe of the fuel supply pipe to form solid fuel in the raw material filling layer below the lower end opening of the inner pipe. Vertical firing characterized in that a space is formed in which particles can fall .