JPH0132176B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cement clinker firing device,
More specifically, the present invention relates to a cement clinker calcination device that combines a rotary furnace or fluidized calcination reactor, a suspension type raw material preheating device, and a calcination device having an independent heat source.

Conventionally, even in cement clinker firing equipment equipped with a so-called suspension-type raw material preheating device, the decarboxylation rate of the raw material in the preheating device is approximately 40%.
It is generally difficult to achieve a decomposition rate exceeding 60%, and the decarboxylation reaction of the remaining undecomposed portion of the raw material, which is approximately 60% or more, must be carried out in a rotary furnace or fluidized calcination reactor. Therefore, the calcination zone that supplies heat for the calcination reaction must be long, and the scale of the rotary furnace or the fluidized calcination reactor that replaces it will inevitably become large. In connection with the residence time, there were problems such as increased heat consumption for firing, adhesion of the alkaline content of the molten raw material to the flue and machine walls, and operational problems due to condensation.

The purpose of the present invention is to solve the above-mentioned technical problems,
An object of the present invention is to provide a cement clinker firing device with improved cement production capacity.

The present invention has a throat section, a spouted layer chamber where the decarboxylation reaction mainly occurs due to straight upward combustion gas and is equipped with a burner, and an upper chamber where mixing, diffusion, and heat exchange are performed by the swirling flow of the introduced gas. In a cement clinker firing apparatus, a roughly cylindrical calcining furnace successively arranged upwardly is installed and arranged between a rotary furnace or a fluidized calcination reactor and a suspension-type raw material preheating device. A duct for introducing preheated combustion air from a cooling device following the rotary furnace or fluidized calcination reactor is connected to the throat part, and a duct for introducing preheated combustion air from a cooling device subsequent to the rotary furnace or the fluidized calcination reactor is connected to the duct near the upper end of the spouted bed chamber in the tangential direction A duct for introducing combustion exhaust gas from the rotary furnace or fluidized calcination reactor is connected to the axis of the furnace at a substantially right angle, and a blow-through prevention member is provided near the upper end of the spouted bed chamber and on the axis of the calciner; A raw material chute for supplying the raw material preheated by the suspension type raw material preheating device is connected near the lower part of the upper chamber, and a decarboxylation reaction occurs with the combustion exhaust gas from the spouted bed chamber and the rotary furnace or fluidized calcination reactor. A conduit for feeding the finished raw material to the lowermost cyclone of the suspension type raw material preheating device was attached tangentially to the side wall near the top of the upper chamber and approximately perpendicular to the axis of the calciner. This is a cement clinker firing device characterized by the following.

The present invention also includes a throat section, a spouted layer chamber where the decarboxylation reaction is mainly carried out by the straight-up ascending combustion gas and is equipped with a burner, and an upper chamber where mixing, diffusion, and heat exchange are performed by the swirling flow of the introduced gas. In a cement clinker firing device, a roughly cylindrical calcining furnace, which is continuous from the bottom to the top, is installed and arranged between a rotary furnace or a fluidized calcination reactor and a suspension type raw material preheating device, A duct is connected for introducing a portion of preheated combustion air from a cooling device following the rotary furnace or fluidized calcination reactor into the spouted bed chamber tangentially and substantially perpendicular to the axis of the calcination furnace; A duct is connected to introduce the remainder of the combustion air into the throat, and a duct is connected near the upper end of the spouted bed chamber from the rotary furnace or fluidized calcination reactor in a tangential direction and approximately perpendicular to the axis of the calciner. A duct for introducing combustion exhaust gas is connected, and a blow-through prevention member is provided near the upper end of the spouted bed chamber and on the axis of the calciner, and the raw material is supplied with the raw material preheated by the suspension type raw material preheating device. A chute is connected to the lower part of the upper chamber, and the combustion exhaust gas from the spouted bed chamber and the rotary furnace or fluidized calcination reactor and the raw material after the decarboxylation reaction are transferred to the lowermost stage of the suspension type raw material preheating device. A cement clinker firing apparatus characterized in that a conduit for feeding the cyclone is attached tangentially to the side wall near the top of the upper chamber and substantially perpendicular to the axis of the calciner.

Furthermore, the present invention provides a throat section, a spouted layer chamber where the decarboxylation reaction is mainly carried out by the straight-up ascending combustion gas and is equipped with a burner, and an upper chamber where mixing, diffusion, and heat exchange are performed by the swirling flow of the introduced gas. A roughly cylindrical calcining furnace consisting of continuous calcining furnaces from the bottom to the top is installed between the rotary furnace or fluidized calcining reactor and the suspension-type raw material preheating device.
In the cement clinker firing apparatus, the throat part is connected to a duct for introducing preheated combustion air from a cooling device subsequent to the rotary furnace or the fluidized fluidized firing reactor, and the spouted bed chamber is A duct for introducing combustion exhaust gas from the rotary furnace or fluidized calcination reactor is connected in a tangential direction and approximately perpendicular to the axis of the calciner near the upper end of the spouted bed chamber. A blow-through prevention member is provided on the axis of the furnace, and a chute is connected to supply a part of the raw material preheated by the suspension type raw material preheating device to the throat part,
A raw material chute for supplying the remainder of the preheated raw material is connected near the lower part of the upper chamber, and the flue gas from the spouted bed chamber and the rotary furnace or fluidized calcination reactor is connected to the raw material for which the decarboxylation reaction has been completed. A conduit for feeding the lowermost cyclone of the suspension-type raw material preheating device is attached tangentially to the side wall near the top of the upper chamber and substantially perpendicular to the axis of the calciner. This is a cement clinker firing device.

The present invention also includes a throat section, a spouted layer chamber where the decarboxylation reaction by straight-rising combustion gas mainly takes place and is equipped with a burner, and an upper chamber where mixing, diffusion, and heat exchange are performed by the swirling flow of the introduced gas. In a cement clinker firing device, a roughly cylindrical calcining furnace that is continuous from the bottom to the top is installed and arranged between a rotary furnace or a fluidized calcination reactor and a suspension type raw material preheating device, A duct for introducing preheated combustion air from a cooling device subsequent to the rotary furnace or fluidized calcination reactor is connected to the throat portion, and a duct is connected to the throat portion near the upper end of the spouted bed chamber in a tangential direction and temporarily. A duct for introducing combustion exhaust gas from the rotary furnace or fluidized calcination reactor is connected almost perpendicularly to the axis of the calciner, and a blow-through prevention member is provided near the upper end of the spouted bed chamber and on the axis of the calciner. , a chute for supplying a part of the raw material preheated by the suspension type raw material preheating device is connected to a duct for introducing combustion exhaust gas from the rotary furnace or fluidized calcination reactor into the spouted bed chamber, and A raw material chute for supplying the remainder of the raw material is connected near the lower part of the upper chamber, and the combustion exhaust gas from the spouted bed chamber and the rotary furnace or fluidized calcination reactor and the raw material after the decarboxylation reaction are transferred to the suspension type. Cement clinker firing, characterized in that a conduit for feeding the lowermost cyclone of the raw material preheating device is attached tangentially to the side wall near the top of the upper chamber and approximately at right angles to the axis of the calciner. It is a device.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a simplified system diagram showing the basic configuration of the present invention. In FIG. 1, solid arrows indicate the flow of raw materials, and dashed arrows indicate the flow of gas. The raw material introduced into the duct 2 from the raw material hopper 1 is blown up by high-temperature exhaust gas from below, exchanges heat, is collected by the cyclone 3, and falls to the lower stage. Next, the raw material is supplied to the calciner 9 along the route of duct 4 → cyclone 5 → duct 6 → cyclone 7 → raw material chute 8. On the other hand, high-temperature exhaust gas from the calciner 9 in the suspension type raw material preheating device 10 is transmitted through the conduit 11 → cyclone 12 → duct 6 → cyclone 7 → duct 4 → cyclone 5 → duct 2 →
It rises like a cyclone 3 and is finally dissipated into the atmosphere through the exhaust duct 13, induced fan 14, etc. The raw material input from the raw material hopper 1 is decarboxylated by heat exchange with this high-temperature exhaust gas. The raw material calcined in the calcining furnace 9 passes through a conduit 11, is collected by a cyclone 12, and is fed into a rotary kiln 15 as a rotary furnace. In the rotary kiln 15, the raw material is burned by the burner 16 to become clinker, and this clinker is heated by the cooling device 17.
After cooling, it is taken out as a product.

Combustion air preheated to 700 to 800° C. is introduced from the cooling device 17 through a duct 18 from below the calciner 9 . The combustion exhaust gas from the rotary kiln 15 is introduced into the vicinity of the center of the calciner 9 in the axial direction through a duct 19 .

The cylindrical calcining furnace 9 has an axis extending vertically,
Basically, there is a throat section 20 with a small diameter connected to the duct 18, a spouted layer chamber 21 with a large diameter connected to the throat section 20, and an upper chamber 22 where a swirling flow occurs.
including. The spouted bed chamber 21 includes burners 23 and 24.
Heavy oil, gas, or other fuel is injected through the cooling device 17 and combusted by combustion air from the cooling device 17. Combustion air from the cooling device 17 passes through the throat portion 20 at high speed, blows through the enlarged portion, that is, the center of the spouted layer chamber 21, and directly rises. Spouted layer chamber 2
In No. 1, the cross section of the calciner rapidly expands, so a large amount of the raw material is present near the inner wall surface, and heat is exchanged with the raw material by combustion of the fuel from the burners 23 and 24, and decarboxylation is rapidly performed. It will be done.

The combustion exhaust gas from the rotary kiln 15 is introduced tangentially into the vicinity of the upper end of the spouted bed chamber 21 via a duct 19, similar to the embodiment shown in FIG. Become. Due to this swirling flow, the relatively heavy raw material, which is incompletely calcined, falls along the inner wall surface into the spouted bed chamber 21 and undergoes heat exchange again. Only the raw material completely calcined in this way is tangentially attached to the side wall near the top of the upper chamber 22.
and a conduit 1 installed at right angles to the axis of the calciner 9
1 to cyclone 12.

FIG. 2 is a simplified system diagram showing the basic structure of the present invention, and FIG. 3 is a sectional view taken along the cutting plane line - in FIG. 2. This configuration is similar to the previous embodiment, and corresponding parts are given the same reference numerals. What should be noted is the spouted layer chamber 21 and the upper chamber 2.
A constriction portion 25 made of a refractory material is provided near the boundary of 0. The constricted portion 25 is formed concentrically with the calcination furnace 9 so as to protrude inward in the radial direction of the calcination furnace 9, thereby preventing incomplete calcination along with the gas flow rising from the throat portion 20 at high speed. It is possible to prevent the so-called blow-through phenomenon in which the raw material is discharged from the calciner 9 through the center of the upper chamber 22. Further, by providing the constriction portion 25 near the upper end of the spouted bed chamber 21, the amount of raw material retained in the spouted bed chamber 21 is increased, and heat exchange in the spouted bed chamber 21 is performed effectively. In addition, the incompletely calcined raw material separated in the upper chamber 22 falls along the inner wall surface of the calciner 9, stays above the constriction part 25, and is removed from the rotary kiln 15 introduced from the duct 19. Heat exchange with high-temperature exhaust gas accelerates the calcination reaction. Other configurations are similar to those described above.

FIG. 4 is a simplified system diagram of one embodiment of the present invention, FIG. 5 is a sectional view taken along the section line V-V in FIG. 4, and FIG. FIG. This embodiment is similar to the structure described above, and corresponding parts are provided with the same reference numerals. In this embodiment, instead of the throttle part 25 having the above-mentioned configuration, a blow-by prevention means 26 made of a refractory is provided in the spouted bed chamber 2.
1 and the upper chamber 22 near the boundary. The blow-through prevention means 26 includes a blow-through prevention member 27 that narrows in the vertical direction, and a plate-shaped support member 2 for supporting the blow-through prevention member 27 on the axis of the calciner 9.
8. The blow-through prevention means 26 makes it possible to prevent blow-through at the center of calcination. Furthermore, the high-velocity gas flow in the center of the calciner is directed radially outward by the blow-through prevention means 26, causing incompletely calcined raw materials to reach the inner wall of the calciner 9 and fall. , whereby the separation effect is effectively carried out. The rest of the configuration is the same as the configuration shown in FIG.

FIG. 7 is a simplified system diagram of another embodiment of the present invention, and FIG. 8 is a sectional view taken along the section line - in FIG. 7. This embodiment is similar to the configuration shown in FIG. 1, and corresponding parts are provided with the same reference numerals. In this embodiment, a part of the preheated air from the cooling device 17 is branched off from the duct 18 as the combustion air for the burners 23 and 24 and sent to the spouted bed chamber 21 via the duct 29 as shown in FIG. Introduce it tangentially like so. As a result, a region rich in combustion air is formed near the inner wall of the spouted bed chamber 21, and combustion in the burners 23 and 24 is completed. Further, since the swirling force within the calcining furnace increases, separation of incompletely calcined raw materials is promoted, and heat exchange in the spouted bed chamber 21 and calcining reaction of the raw materials are performed more effectively. Other configurations are
The configuration is similar to that shown in FIG. This embodiment may be implemented in combination with the configurations shown in FIGS. 2 and 4.

FIG. 9 is a simplified system diagram of yet another embodiment of the present invention. This embodiment is similar to the configuration shown in FIG. 1, and corresponding parts are provided with the same reference numerals. It should be noted that the raw material chute 8 is provided with a branch damper 30, which supplies part or all of the raw material to the throat section 20 via the chute 31. As a result, the raw material and combustion air are sufficiently mixed in advance, and heat exchange in the calciner 9 is improved. Furthermore, the energy of the high-velocity gas from the throat portion 20 is used to raise the raw material, thereby preventing the so-called blow-by phenomenon.
In addition, in the configuration in which all of the raw material is introduced near the upper end of the spouted bed chamber 21 as in the above embodiment, some of the raw material does not fall to the throat part 20 and is left in the calciner in an incomplete state. Although it may be discharged from 9,
In this embodiment, such a situation does not occur. Other configurations are similar to those shown in FIG. This embodiment may also be implemented in combination with the configurations of the previous embodiments.

FIG. 10 is a simplified system diagram of another embodiment of the invention, in which parts similar to and corresponding to the embodiment shown in FIG. 9 are given the same reference numerals. In this embodiment, part or all of the raw material preheated by the branch damper 30 is introduced via the chute 32 into a vertical portion of the duct 19 that guides high-temperature exhaust gas from the rotary kiln 15. The raw material introduced into the duct 19 is transported upward while exchanging heat with the high-temperature kiln exhaust gas, and introduced into the calciner 9 in a tangential direction. The raw material introduced into the calciner 9 is separated by the swirling flow and falls to the lower end of the jet chamber 21 along the wall surface. By charging the raw material into the duct 19 in this manner, the duct 19 is also used as a place for heat exchange, so the calcining furnace 9 can be downsized. Furthermore, the temperature of the kiln exhaust gas in the duct 19 decreases rapidly due to heat exchange with the raw material.
This makes it possible to prevent coating on the inner wall of the kiln due to alkali compounds in the kiln exhaust gas.
Stable operations can be maintained. The other configurations are similar to the embodiment shown in FIG.
Other embodiments of the present invention are shown in FIGS. 2, 4, and 7.
The configuration shown in FIG. 9 and FIG. 9 may be combined with the configuration of this embodiment.

Similar to FIG. 4 above, in each of the embodiments shown in FIGS. 7, 9, and 10, the blow-through prevention means 2
6 is provided.

As described above, according to the present invention, high-temperature raw materials containing almost 100% decarboxylated limestone can be supplied to a rotary furnace or fluidized calcination reactor through efficient calcining reaction, so rotary furnaces and the like can be downsized. As a result, the residence time of raw materials is shortened, the amount of alkali volatilized in the rotary furnace or fluidized calcination reactor is reduced, and the required heat consumption is reduced, resulting in a significant improvement in cement production capacity.

In particular, according to the present invention, by providing the blow-through prevention member, the following excellent effects are achieved.

(a) It is possible to reliably prevent uncalcined raw materials from blowing through in the center of the spouted bed.

(b) Since the uncalcined raw material has a high specific gravity, it collides with the blow-through prevention member, changes direction, reaches the side wall of the spouted bed chamber, and falls near the throat. Therefore, the amount of retention in the spouted bed chamber increases, and the amount of heat exchange and the calcining rate of the raw material improve.

(c) Blow-through of combustion air from the center of the spouted bed can be prevented, improving combustion efficiency between the spouted bed chambers.

(d) With each of the effects of items (b) and (c) above, the calciner can be made smaller and the heat consumption can also be reduced.

(e) Blow-through of raw materials and combustion air in the center of the upper chamber is eliminated, improving heat exchange in the upper chamber.

[Brief explanation of drawings]

Figure 1 is a simplified system diagram showing the configuration that is the basis of the present invention, Figure 2 is a simplified system diagram showing another configuration that is the basis of the present invention, and Figure 3 is a cross section of Figure 2. 4 is a simplified system diagram of an embodiment of the present invention, FIG. 5 is a sectional view taken from the cutting line of FIG. 4, and FIG. 6 is a sectional view of FIG. 4. FIG. 7 is a simplified system diagram of another embodiment of the present invention, FIG. 8 is a sectional view taken along the cutting plane line - of FIG. 7, and FIG. 9 is a schematic diagram of another embodiment of the present invention. Simplified System Diagram of Another Embodiment FIG. 10 is a simplified system diagram of another embodiment of the present invention. 8... Raw material chute, 9... Calciner, 10, 37...
Suspension type raw material preheating device, 15... rotary kiln, 17... cooling device, 20... throat section, 2
DESCRIPTION OF SYMBOLS 1... Spouted bed chamber, 22... Upper chamber, 23, 24... Burner, 25... Throttle part, 26... Blow-through prevention means, 30
...Branch damper.

Claims (1)

[Scope of Claims] 1 Throat part, a spouted bed chamber where the decarboxylation reaction is mainly carried out by the straight-up ascending combustion gas and equipped with a burner, the gas is mixed by the swirling flow of the introduced gas,
A roughly cylindrical calcining furnace consisting of an upper chamber in which diffusion and heat exchange occur successively from the bottom to the top is installed and placed between the rotary furnace or fluidized calcination reactor and the suspension-type raw material preheating device. In the cement clinker firing apparatus, the throat part is connected to a duct for introducing preheated combustion air from a cooling device subsequent to the rotary furnace or the fluidized bed firing reactor, and A duct for introducing combustion exhaust gas from the rotary furnace or fluidized calcination reactor is connected in a tangential direction and approximately perpendicular to the axis of the calcining furnace near the upper end, and a duct is connected near the upper end of the spouted bed chamber to A blow-through prevention member is provided on the axis of the furnace, and a raw material chute for supplying the raw material preheated by the suspension type raw material preheating device is connected near the lower part of the upper chamber, and the spouted bed chamber and the rotary furnace or fluidized calcination are heated. A conduit for feeding the combustion exhaust gas from the reactor and the raw material for which the decarboxylation reaction has been completed to the lowermost cyclone of the suspension type raw material preheating device is provided tangentially to the side wall near the top of the upper chamber, and temporarily installed. A cement clinker firing device characterized in that it is installed almost perpendicular to the axis of a furnace. 2. Throat section, where the decarbonation reaction is mainly carried out by the straight-up ascending combustion gas, and the spouted layer chamber equipped with a burner, where the introduced gas is mixed by the swirling flow.
A roughly cylindrical calcining furnace consisting of an upper chamber in which diffusion and heat exchange occur successively from the bottom to the top is installed and placed between the rotary furnace or fluidized calcination reactor and the suspension-type raw material preheating device. A cement clinker calcination apparatus comprising: directing a portion of the preheated combustion air from a cooling device following the rotary furnace or fluidized calcination reactor tangentially into the spouted bed chamber and along the axis of the calciner. A duct is connected to introduce the remainder of the combustion air into the throat portion, and a duct is connected near the upper end of the spouted bed chamber in a tangential direction and substantially perpendicular to the axis of the calciner. A duct for introducing combustion exhaust gas from the rotary furnace or fluidized calcination reactor is connected to the rotary furnace or the fluidized calcination reactor, and a blow-through prevention member is provided near the upper end of the spouted bed chamber and on the axis of the calcination furnace, and the suspension-type raw material preheating A raw material chute for supplying the raw material preheated by the apparatus is connected near the lower part of the upper chamber, and the combustion exhaust gas from the spouted bed chamber and the rotary furnace or the fluidized sintering reactor and the raw material after the decarboxylation reaction are connected to the upper chamber. A cement characterized in that a conduit for feeding the cyclone at the lowest stage of the suspension type raw material preheating device is attached tangentially to the side wall near the top of the upper chamber and substantially perpendicular to the axis of the calciner. Clinker firing equipment. 3 Throat section, where the decarboxylation reaction is mainly carried out by the straight-up ascending combustion gas, the spouted bed chamber is equipped with a burner, and the swirling flow of the introduced gas causes mixing.
A roughly cylindrical calcining furnace consisting of an upper chamber in which diffusion and heat exchange occur successively from the bottom to the top is installed and placed between the rotary furnace or fluidized calcination reactor and the suspension-type raw material preheating device. In the cement clinker firing apparatus, the throat part is connected to a duct for introducing preheated combustion air from a cooling device subsequent to the rotary furnace or the fluidized bed firing reactor, and A duct for introducing combustion exhaust gas from the rotary furnace or fluidized calcination reactor is connected in a tangential direction and approximately perpendicular to the axis of the calcining furnace near the upper end, and a duct is connected near the upper end of the spouted bed chamber to A blow-through prevention member is provided on the axis of the furnace, and a chute is connected to supply a part of the raw material preheated by the suspension type raw material preheating device to the throat part,
A raw material chute for supplying the remainder of the preheated raw material is connected near the lower part of the upper chamber, and the flue gas from the spouted bed chamber and the rotary furnace or fluidized calcination reactor is connected to the raw material for which the decarboxylation reaction has been completed. A conduit for feeding the lowermost cyclone of the suspension-type raw material preheating device is attached tangentially to the side wall near the top of the upper chamber and substantially perpendicular to the axis of the calciner. Cement clinker firing equipment. 4. Throat section, where the decarboxylation reaction is mainly carried out by the straight-up ascending combustion gas, and the spouted layer chamber equipped with a burner, where the introduced gas is mixed by the swirling flow.
A roughly cylindrical calcining furnace consisting of an upper chamber in which diffusion and heat exchange occur successively from the bottom to the top is installed and placed between the rotary furnace or fluidized calcination reactor and the suspension-type raw material preheating device. In the cement clinker firing apparatus, the throat part is connected to a duct for introducing preheated combustion air from a cooling device subsequent to the rotary furnace or the fluidized bed firing reactor, and A duct for introducing combustion exhaust gas from the rotary furnace or fluidized calcination reactor is connected in a tangential direction and approximately perpendicular to the axis of the calcining furnace near the upper end, and a duct is connected near the upper end of the spouted bed chamber to A blow-through prevention member is provided on the axis of the furnace, and a chute that supplies a part of the raw material preheated by the suspension type raw material preheating device is used to introduce combustion exhaust gas from the rotary furnace or fluidized calcination reactor into the spouted bed chamber. A raw material chute for supplying the remainder of the preheated raw material is connected near the lower part of the upper chamber, and is connected to a duct for decarboxylation with combustion exhaust gas from the spouted bed chamber and the rotary furnace or fluidized calcination reactor. A conduit for feeding the raw material that has been completely heated to the cyclone at the lowest stage of the suspension type raw material preheating device is installed tangentially to the side wall near the top of the upper chamber and approximately perpendicular to the axis of the calciner. A cement clinker firing device characterized by: