JPH0147416B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for firing cement powder raw materials such as limestone, clay, and silica stone, or powder raw materials such as limestone and alumina alone (hereinafter referred to as powder raw materials for cement, etc.).

As a typical prior art, a powder raw material is calcined to almost 100% in a so-called suspension-type raw material preheating device and a calcining furnace with an independent heat source.
There is a technology that involves firing clinker using a rotary kill, cooling the fired clinker, and then taking it out as a product. In this prior art, heat transfer in the rotary kiln occurs at the surface portion of the estimated raw material layer and the contact portion with the rotary kiln wall surface, so the heat transfer area is relatively small.
Therefore, the heat transfer efficiency is poor and the rotary kiln becomes large. As a result, the heat radiation loss from the rotary kiln is large, the installation area becomes large, and the driving power becomes large. In addition, because the temperature of the flame formed in the rotary kiln is high,
As the amount of harmful gases such as NO _x increases,
Since the heat load in the firing area is large, the refractory is severely burnt out.

The present invention solves the above-mentioned technical problems by fluidizing powder raw materials such as cement, and also prevents troubles caused by large lumps of clinker generated in the fluidized bed and falling off of the coating. The purpose of the present invention is to provide a firing device for cement clinker, etc., which enables stable continuous operation.

The present invention has a preheating device consisting of a floating heat exchanger having a plurality of collectors arranged above and below and a calciner having an independent heat source, a first dispersion plate inclined with respect to a horizontal plane, and A fluidized firing furnace that forms a first fluidized bed of powdered raw materials and clinker input from a preheating device on a first distribution plate, and heats and fires the powdered raw materials with a burner; a separator provided in the middle of a duct leading to the fluidized furnace for returning the powdered raw material entrained in the exhaust gas to the fluidized fluidized firing furnace; It has a chute 27 for discharging large lumps from the lower part of the fluidized bed.
A filling cooler that forms a packed bed of large lumps pulled out through the packed bed and cools it by feeding cooling air into the packed bed from the bottom of the packed bed, upward from the top of the first distribution plate. a second dispersion plate spaced apart, the second dispersion plate being inclined downwardly as it approaches the first dispersion plate;
A second layer of clinker and green raw material is placed on the second distribution plate.
A fluidized bed is formed and solidified by cooling, and the first fluidized bed and the second fluidized bed communicate with each other through an opening 17 formed at the bottom of the second distribution plate. and a cooling solidification device having a weir extending upward from the opening 17, of the clinker and unfired raw materials overflowing from the weir of the cooling solidification device, fine clinker and unfired raw materials are suspended in the airflow flowing upward. a chute that causes the coarse clinker to rise and drop only the remaining coarse clinker; a cooling device that is connected to the lower end of the chute and cools the coarse clinker from the chute with cooling air; A dust collector is used to guide the air passing through and rising from the top of the cooling and solidification equipment to the calciner, and to separate fine clinker and unfired powder raw materials along the way and return them to the fluidized fluidized calciner. A calcination device for cement clinker, etc., characterized in that it includes a duct equipped with a container, and a duct for guiding the air heated by the cooling device as fluidized air to at least one of a cooling solidification device and a fluidized fluidized calcination furnace. .

In a preferred embodiment, the packed bed cooler comprises:
It is characterized by being equipped with a roller for crushing large lumps.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of one implementation of the present invention.
In FIG. 1, the flow of solids such as cement raw materials is shown by solid line arrows, and the flow of gases such as combustion exhaust gas is shown by broken line arrows. A powder raw material such as cement is put into a preheating device 2 equipped with a calcining furnace 1 . This powder raw material is preheated by floating in the combustion exhaust gas from the fluidized fluidized furnace 5 and the calciner 1 in the preheating device 2, and then calcined in the calciner 1. The almost completely calcined powder raw material is charged into the fluidized fluidized calcining furnace 5. In the fluidized fluidized firing furnace 5, the powder raw material is fired while flowing, and the clinker and unfired raw material that are sufficiently fired and produced are led to the cooling and solidification device 6. In this cooling and solidification device 6, the clinker and a part of the unfired powder raw material are fluidized by fluidizing air from below, where a part of the unfired powder raw material is separated, and the overflowing clinker and the unfired powder raw material are further separated. The fired powder raw material is led to the chute 21. In the chute 21, the fine clinker and unfired powder raw materials are separated by floating in the high-temperature cooling air that has undergone heat exchange in the cooling device 7, and only the remaining coarse clinker is fed into the cooling device 7, where it is cooled and turned into a product. taken out. The fine clinker and the unfired powder raw material suspended in the cooling air and separated are returned to the fluidized firing furnace 5 together with the unfired powder raw material suspended in the fluidized air by the cooling solidification device 6. Further, large chunks of coarse clinker and fallen coating that have settled in the lower part of the fluidized bed 16 of the fluidized firing furnace 5 are discharged to the packed bed cooler 8, and after being cooled in the packed bed cooler 8, are discharged.

On the other hand, among the cooling air introduced into the cooling device 7, the air heated to a relatively high temperature through heat exchange with the clinker is used together with the air heated to a high temperature in the cooling and solidification device 6 to undergo calcining. It is used as combustion air for the burner 9 in the furnace 1. Furthermore, the air heated to a relatively low temperature in the cooling device 7 is used as fluidizing air in the cooling and solidifying device 6 and the fluidized fluidized firing furnace 5, respectively. The combustion exhaust gas and surplus air from the fluidized fluidized furnace 5 are led to the preheating device 2 via the separator 11, where they exchange heat with the powder raw material and are then discharged.

The preheating device 2 consists of a floating heat exchanger 12 and a calciner 1. The floating heat exchanger 12 includes collectors C1 to C5, such as cyclones, arranged in five upper and lower stages, and each collector C1 to C5 is connected to a duct D2 to D.
5 are connected to each other. Also, the bottom collector C
1 and the calcining furnace 1 are connected via a duct D1.

In such a preheating device 2, the combustion exhaust gas from the burner 9 in the calcining furnace 1 and the exhaust gas from the fluidized fluidized calcining furnace 5 are transferred from the duct D1 to the collector C1 to the duct D.
2 → Collector C2 → Duct D3 → Collector C3 → Duct D4 → Collector C4 → Duct D5 → Collector C5 and is discharged. On the other hand, the powder raw material input from the input hopper 13 connected in the middle of the duct D5 descends sequentially through the collector C5 → C4 → C3 → C2, exchanges heat with the exhaust gas, is preheated, and is input into the calciner 1. be done. After the powder raw material is calcined to about 80 to 90% in the calcining furnace 1, it is fed into the fluidized fluidized calcining furnace 5 through the collector C1.

FIG. 2 is a sectional view taken along the section line - in FIG. 1. The fluidized fluidized firing furnace 5 has an upright cylindrical shape, and a dispersion plate 14 is provided at the lower part thereof so as to be inclined with respect to the horizontal plane. An air chamber 15 is provided below the dispersion plate 14 , and the fluidized air introduced into the air chamber 15 flows upwardly through the dispersion plate 14 . A fluidized bed 16 of calcined clinker and powder raw materials is formed. A plurality of burners 10 are provided on the side wall of the fluidized firing furnace 5 corresponding to the fluidized bed 16 at intervals in the circumferential direction.

An exhaust gas duct 45 connected to the upper part of the fluidized furnace 5 is connected to a separator 11 such as a cyclone. This separator 11 is installed directly below the calciner 1 , and a rising duct 46 extending directly upward from the top of the separator 11 is connected to the bottom of the calciner 1 . Note that the lowermost collector C1 in the preheating device 2
The bottom of the collector C1 is connected to the chute 47 etc. via the chute 48, and therefore the collector C1
The almost calcined powder raw material collected by the separator 11 is transferred to the fluidized fluidized firing furnace 5
will be put into the

In the fluidized firing furnace 5, the fluidized bed 16 is maintained at, for example, about 1400 to 1500°C. In this fluidized bed 16, the powder raw material is melted and aggregated to form a nucleus, or is attached to particles that have already become clinker, and is granulated and fired. In this fluidized bed 16, the fluidization speed is kept relatively high at about 2 to 3 m/sec, and the powder raw material and clinker move vigorously to mix and diffuse within the fluidized bed 16. Therefore, it is possible to prevent particles from adhering to each other or to the furnace wall and the distribution plate 14.
Further, the mixing of the fuel (for example, lime) blown from the burner 10 and the powder raw material is promoted, and the temperature distribution within the fluidized bed 16 becomes uniform accordingly, making it possible to obtain high-quality clinker.

An opening 17 is formed in the side wall above the distribution plate 14 of the fluidized fluidized firing furnace 5, and the cooling solidification device 6 is provided in communication with each other through the opening 17. The cooling and solidifying device 6 extends vertically by sharing a part of the side wall of the fluidized-bed kiln 5, for example, and a dispersion plate 18 is provided below the position corresponding to the opening 17. Therefore, this dispersion plate 1
A portion of the clinker and green powder raw material flowing from the fluidized bed 16 through the opening 17 due to the air flowing upward through the dispersion plate 18 forms a fluidized bed 19 above the distribution plate 18 . As is clear from Figure 1,
A dispersion plate 18 is arranged at a distance above the top of the dispersion plate 14 (the left end in FIG. 1).
This dispersion plate 18 is inclined downward as it approaches the dispersion plate 14 (to the right in FIG. 1). Fluidized bed 1
6 and 19 communicate with each other through an opening 17 formed at the bottom of the distribution plate 18. Dispersion plate 1
8 and the opening 17, a weir 20 is formed extending upward from the opening 17.

On the opposite side of the cooling solidification device 6 from the fluidized firing furnace 5,
A weir 20 is provided at the same position as the upper surface of the fluidized bed 16 for overflowing a portion of the clinker and green powder raw material. The clinker and unfired powder raw materials overflowing from this weir 20 are guided to the cooling device 7 via the chute 21.

The upper parts of the chute 21 and the cooling solidification device 6 are commonly connected to a duct 22, and the duct 2
2 is connected to a dust collector 23 such as a cyclone.
The outlet of the dust collector 23 is connected to the calciner 1 through a duct 24.
connected to. The particles collected by the dust collector 23 are returned to the fluidized fluidized firing furnace 5 via the chute 25.

In the fluidized fluidized firing furnace 5, an opening 26 including a gate 56 is formed in the side wall corresponding to the lowest portion of the distribution plate 14. A chute 27 extending vertically is connected to this opening 26 , and the chute 27 is connected to the upper part of the packed bed cooler 8 . The packed bed cooler 8 has an upright cylindrical shape, and is provided with an umbrella-shaped blowing portion 28 at its lower part for feeding cooling air. The blowing section 28 includes a plurality of blowing pipes 29 arranged at intervals in the circumferential direction of the packed bed cooler 8.
It is supported by and placed approximately in the center of the packed bed cooler 8. Each blow pipe 29 is a forced air blower 3
Connected to 0. A damper 32 is provided in the middle of a chute 31 connected to the bottom of the packed bed cooler 8 .

A casing 33 of the cooling device 7 is in the shape of a sealed box extending in the transverse direction, and a lower end portion of the chute 21 is connected to one end portion of the casing 33. A dispersion plate 34 is provided in the lower part of the casing 33, and the lower part of the dispersion plate 34 is divided into two in the lateral direction, and cooling air chambers 35 and 36 are provided respectively. Forced air blowers 37 and 38 are connected to each cooling air chamber 35 and 36, respectively.

The fluidized bed 39 formed above the distribution plate 34 is
It is divided into multiple parts to efficiently cool the high temperature clinker. For example, in the embodiment shown in FIG.
The portions of the fluidized bed 39 corresponding to the cooling air chambers 35 and 36 are each divided into two parts. In addition, the space above the fluidized bed 39 in the casing 33 is divided by overpartitions 40 corresponding to the high temperature air recovery area, and one space 4
1 is connected to the chute 21, and the other space 42 is connected to an air exhaust pipe 43. By dividing the inside of the casing 33 in this way, the air sent into the space 41 is guided to the chute 21, and the air sent into the space 41 is guided to the chute 21.
The air introduced into 2 is guided to an air exhaust pipe 43. Further, at the other end of the casing 33, an overflow pipe 44 is connected near the top of the fluidized bed 39, and the clinker introduced from the chute 21 flows inside the fluidized bed 39 from one end to the other end (as shown in FIG. While moving from the right end to the left end, the product is cooled by cooling air and taken out as a product from the overflow pipe 44.

The air exhaust pipe 43 is connected to a dust collector 50 and a blower 51.
It is connected to the air chamber 15 of the fluidized fluidized kiln 5 through a duct 52 which includes the following. Further, a branch duct 53 is connected to the duct 52 on the downstream side of the blower 51.
3 is connected to the bottom of the cooling and solidifying device 6. Further, a discharge pipe 54 is connected to the duct 52 on the upstream side of the dust collector 50, and residual air introduced into the cooling solidification device 6 and the fluidized fluidized firing furnace is discharged from the discharge pipe 54. The particles collected by the dust collector 50 are thrown into the chute 21 as indicated by an arrow 55.

In the fluidized firing furnace 5, the fluidized bed 16 is formed by fluidizing powder particles by air heated to a relatively low temperature by the cooling device 7, and therefore the amount of fuel burned by the burner 10 is reduced. thermal efficiency is improved. In addition, since large lumps such as clinker and fallen coating that have become coarse in the fluidized bed 16 settle, they are guided to the large lump discharge chute 27 along the inclined distribution plate 14 and form a packed bed 59 in the packed bed cooler 8. do. In this packed bed cooler 8, air is introduced upward into the packed bed 59 from the blowing section 28 at the bottom of the packed bed 59. Therefore, even if fine clinker and unfired raw materials enter the chute 27 from the fluidized bed 16 of the fluidized firing furnace 5, these particles are suspended upward by the air and returned to the fluidized bed 16. The large mass cooled by the air from the blowing section 28 is discharged by the rotary damper 32 while maintaining airtightness. On the other hand, packed bed cooler 8
The heat-exchanged high-temperature air is guided into the fluidized bed from the opening 26 via the chute 27, where it is mixed with the fluidized air that has flowed from below.
It is used as combustion air for the burner 10.

As another embodiment of the present invention, part or all of the powder raw material collected by the collector C1 of the preheating device 2 is transferred to an exhaust gas duct 45 upstream of the separator 11.
Alternatively, it may be introduced into the upper part of the cooling and solidifying device 6 in the duct 22. This allows the temperature of the exhaust gas or high-temperature air to be lower than the liquid phase formation temperature of clinker, thereby preventing coaching troubles.

FIG. 3 is a system diagram of another embodiment of the present invention,
Parts corresponding to the embodiments of FIGS. 1 and 2 are given the same reference numerals. In this embodiment, a crushing roller 60 is provided at the lower part of the packed bed cooler 8, and the crushing roller 60 can crush and discharge large lumps such as coarse clinker and fallen coating.

As described above, according to the present invention, the following effects can be achieved. (1) Since the preheating device includes a calciner equipped with a burner, the powder raw material introduced into the fluidized fluidized furnace has already been decarboxylated to about 80 to 90%, and therefore reduces the heat load of the fluidized fluidized furnace. As a result, the fluidized fluidized kiln can be made smaller, and the installation area and heat dissipation loss are reduced. (2) Since clinker is generated in the fluidized bed at a relatively high temperature, the generation of harmful gases such as NOx is suppressed as much as possible, and burnout of refractories is also prevented as much as possible. (3) The clinker granulated by fluidized firing has a relatively small diameter, and the power required to crush the clinker taken out as a product is reduced. (4) Large lumps such as coarse clinker and fallen coating generated during fluidized firing are discharged along the inclined dispersion plate, allowing stable continuous operation. (5) Since product clinker with a relatively uniform particle size is charged into the cooling device separately from the large clinker, blow-by of cooling air in the cooling device is prevented and cooling is efficiently achieved. (6) Since the clinker is cooled and solidified by the cooling and solidifying device, a material seal is achieved between the fluidized fluidized kiln and the cooling device, and the cooling device is made smaller. (7) A duct is provided to guide the air heated by the cooling device and the air from the upper part of the cooling and solidification device to the calcining furnace, and a dust collector is installed in the middle of the duct to collect fine clinker and unfired powder raw materials. Since the air is separated and returned to the fluidized calcination furnace, and the air heated by the cooling device is led as fluidized air to at least one of the cooling solidification device and the fluidized calcination furnace, the consumption amount is reduced.

That is, in the present invention, the first dispersion plate of the fluidized calcining furnace is tilted, and a packed bed cooler is provided at the bottom of the incline to receive the large lumps, and a space is provided above the top of the first dispersion plate for cooling and solidification. A second distribution plate of the device is provided, the second distribution plate sloping downwardly as it approaches the first distribution plate. Therefore, it is possible to reliably prevent large lumps in the fluidized fluidized furnace from entering the cooling and solidifying device. This can reliably prevent large lumps from entering the cooling device and being taken out as a product.

Furthermore, in the present invention, as described above, the cooling and solidifying device is provided with a weir extending upwardly from the second distribution plate and the opening 17, so that the clinker and unfired material from the first fluidized bed of the fluidized fluidized furnace are Raw materials are the second
A second fluidized bed forms on the distribution plate, overflows the weir and enters the chute. In this chute, the fine clinker and unfired raw materials of the clinker overflowing from the weir are floated upward and collected by the dust collector described later, and only the coarse clinker is guided to the cooling device. That's what I do.

It is therefore possible to improve the quality of the clinker product obtained from the cooling device.

In addition, there is no need to separately introduce fine clinker, which is the granulation nucleus required in a fluidized fluidized firing furnace, into the fluidized fired furnace.
This makes it possible to improve thermal efficiency.

In addition, in a cooling solidification device, even if the height of the fluidized bed is smaller than that in a fluidized calcination furnace, a sufficient function can be achieved. An excellent effect of reducing power consumption is achieved.

[Brief explanation of drawings]

FIG. 1 is a system diagram of one embodiment of the present invention, FIG. 2 is a sectional view taken along the cutting plane line - of FIG. 1, and FIG. 3 is a system diagram of another embodiment of the present invention. 1... Calcination furnace, 2... Preheating device, 5... Fluidized fluidized calcination furnace, 6... Cooling solidification device, 7... Cooling device, 8
...Filled bed cooler, 9,10...Burner, 11...
...Separator, 12...Floating heat exchanger, 14,1
8, 34... Dispersion plate, 16, 39... Fluidized bed, 2
1, 25, 27, 31, 47, 48... Shoot, 22, 24, 52... Duct, 23, 50...
... Dust collector, 45 ... Exhaust gas duct, 46 ... Standing duct, 53 ... Branch duct, 60 ... Crushing roller, C1 to C5 ... Collector.

Claims (1)

[Claims] 1. A preheating device consisting of a floating heat exchanger in which a plurality of collectors are arranged above and below and a calciner having an independent heat source, and a first dispersion plate inclined with respect to the horizontal plane. a fluidized firing furnace in which a first fluidized bed of powdered raw material and clinker inputted from the preheating device is formed on a first distribution plate, and the powdered raw material is heated and fired by a burner; a separator provided in the middle of a duct leading to the preheating device and for returning the powdered raw material entrained in the exhaust gas to the fluidized fluidized firing furnace; The large lump discharge chute 27 is provided from the lower part of the fluidized bed.
A filling cooler that forms a packed bed of large lumps pulled out through the packed bed and cools it by feeding cooling air into the packed bed from the bottom of the packed bed, upward from the top of the first distribution plate. a second dispersion plate spaced apart, the second dispersion plate being inclined downwardly as it approaches the first dispersion plate;
A second layer of clinker and green raw material is placed on the second distribution plate.
A fluidized bed is formed and solidified by cooling, and the first fluidized bed and the second fluidized bed communicate with each other through an opening 17 formed at the bottom of the second distribution plate. and a cooling solidification device having a weir extending upward from the opening 17, of the clinker and unfired raw materials overflowing from the weir of the cooling solidification device, fine clinker and unfired raw materials are suspended in the airflow flowing upward. a chute that causes the coarse clinker to rise and drop only the remaining coarse clinker; a cooling device that is connected to the lower end of the chute and cools down the coarse clinker from the chute with cooled air; The air flowing upward through the chute and the air from the upper part of the cooling solidification equipment are guided to the calcining furnace, and along the way, fine clinker and unfired powder raw materials are separated and returned to the fluidized fluidized calcining furnace. A calcination device for cement clinker or the like, comprising: a duct equipped with a dust collector; and a duct for guiding air heated by the cooling device as fluidized air to at least one of a cooling solidification device and a fluidized calcination furnace. 2. The apparatus for firing cement clinker or the like according to claim 1, wherein the packed bed cooler includes a crushing roller for crushing and discharging large lumps.