JPS6259389A - Plural system type powder material preheater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a multi-system preheating device for powdered raw materials such as cement, alumina, lime, etc.

(Prior Art) Conventionally, powder raw material preheating devices have been configured in various ways, some of which are configured as follows. In other words, fuel is combusted in the calciner using an exhaust gas system preheating device that mainly uses the exhaust gas from the calciner, and high-temperature exhaust air from the cooling device for fired products, and the combustion gas generated by this is mainly used. There is a preheating device that has multiple systems including combustion gas system preheating devices to be used.

As mentioned above, in the calcining method in which each preheating device is installed in parallel with the gas flow, the combustion furnace exhaust gas does not pass through the calciner located in the combustion gas system, so the fuel is combusted in the calciner. It has the advantage that it has excellent performance and that the calciner can be constructed compactly.

However, in the case of a preheating device with multiple systems as described above, in order to balance the thermal work per powder raw material processed in each system and to highly calcinate the powder raw materials in both systems, it is necessary to It is conventional practice to configure the powder raw material passing through the preheating device to pass in series through the lowermost heat exchange stage of the reheating device.

This conventional example will be specifically explained with reference to a system diagram of a cement raw material firing apparatus shown in FIG.

In the figure, 1 is a firing furnace for firing cement raw materials to obtain talinka, and 2 is a cooling device for cooling the talinka discharged from the firing furnace 1 by air flow.

An exhaust gas system preheating device 3 for preheating the powder raw material with the exhaust gas from the firing furnace 1 is connected to the firing furnace 1, and
A combustion gas system preheating device 4 is connected to the cooling device 2, which combusts fuel using the exhaust air from the cooling device 2 and preheats the powder raw material with the combustion gas. Further, the firing furnace 1 is connected to a cooling device 2 through an air passage 6, and high-temperature exhaust air from the cooling device 2 is sent into the firing furnace 1 through this air passage 6 for fuel combustion in the firing furnace 1. It will be done.

The above exhaust gas system preheating device @3 will be explained.

This exhaust gas system preheating device 3 has powder separators C11''CW such as cyclones stacked vertically, and includes a gas outlet of each powder separator and a gas inlet of another powder separator above this powder separator. The gas outlet of the firing furnace 1 and the gas inlet of the powder separator C at the lowest stage are also connected by the gas duct 7a.

Further, the gas discharge port of the powder separator C11 at the top stage is connected to the exhaust gas fan 12a by a gas duct 7b.

The gas inlets of each powder separator except for the top and bottom powder separators cn and c are connected to the powder discharge ports of other powder separators above these powder separators by raw material chutes 13, respectively. . Further, a raw material supply port 16 into which a powder raw material is introduced is provided in the gas duct 7a on the gas inlet side of the powder separator Cn at the uppermost stage. On the other hand, the powder discharge port of the powder separator C at the lowest stage is connected to the firing furnace l by a raw material chute 14.

Next, the combustion gas system preheating device 4 will be explained.

This combustion gas system preheating device 4 is constructed similarly to the above-mentioned exhaust gas system preheating device 3, and has powder separators C stacked vertically.
21"' C24 and an exhaust gas fan 12b, as well as gas ducts 7a, 7b and a raw material chute 13 that connect these. Also, in this combustion gas system preheating device 4, the powder separator at the lowest stage The exhaust air from the cooling device 2 is used between the gas inlet side gas duct 7a of C24 and the powder outlet of the powder separator C23 located above the powder separator C24 to combust fuel and preheat the powder raw material. A calciner 8 is provided which is connected to the cooling device 2 by an exhaust air duct 9 and is provided with an independent fuel supply device 10 .

Further, the powder discharge port of the second-stage powder separator C13 from the bottom in the exhaust gas system preheating device 3 is connected to the calciner 8 of the combustion gas system preheating device 4 by a raw material chute 15, and the combustion gas system preheating device Powder separator C24 of device 4
The powder outlet of the exhaust gas system preheating device 3 is connected to the gas inlet side gas duct 7a to the powder separator C by a raw material chute 18.

The high-temperature exhaust air that has been cooled by the cooling device 2 is burned in the firing furnace 1 to become exhaust gas, and in the exhaust gas system preheating device 3, it is sucked by the exhaust gas fan 12a and sent from the powder separator CI4 at the lowest stage. The powder is passed to the top powder separator Cn. In addition, the combustion gas system preheating device 4
In.

The exhaust air from the cooling device 2 is burned in a calciner 8,
This gas is sucked by the exhaust gas fan 12b and flows from the lowest powder separator C24 to the uppermost powder separator C2+ (the flow of the exhaust gas is indicated by solid arrows in the figure).

On the other hand, the powder raw material inputted from each raw material supply port 18.18 is transferred to the powder separator CI1 at the top stage of each preheating device 3.4. C
21, flows toward the lower stage, is fired in the firing furnace 1, becomes talin, is cooled in the cooling device 2, and is transferred to the next process (in the figure, the flow of the powder raw material is indicated by a broken line arrow).

In the above case, the entire amount of the preheated powder raw material discharged from the second-stage powder separator CT3 from the bottom in the exhaust gas system preheating device 3 is supplied to the calciner 8 of the combustion gas system preheating device 4. Therefore, the powder raw material is used in the combustion gas system preheating device 4.
Together with the powder raw material from the powder separator C23 in the second stage from the bottom, it is partially calcined in the calciner 8, and is then used in the lowest stage powder separator C24 of the combustion gas system preheating device 4 and the exhaust gas system preheating device 3. While passing through the lowermost powder separator C in series, a higher degree of calcination is achieved and the powder is supplied to the firing furnace I. Note that the exhaust gas system preheating device 3 and the combustion gas system preheating device 4
Contrary to the above, the preheated powder raw material discharged from the powder separator C13° C23 in the second stage from the bottom is transferred from the lowest heat exchange stage of the exhaust gas system preheating device 3 to the combustion gas system preheating device 4.
Even when passing in series in the order of the lowest heat exchange stage,
A similar effect of accelerating calcination can be obtained.

(Problems to be Solved by the Invention) By the way, the calcining reaction of limestone particles, that is, the decarboxylation reaction (
CaCO3→CaO+ CO2), if the temperature of the particles and the partial pressure of carbon dioxide in the atmospheric gas are the same,
Fine-grained powders require a short reaction time, ie, residence time in a high-temperature gas, but coarse-grained powders require a long residence time in proportion to their particle size. On the other hand, the recarbonation reaction (C
aO+ CO2→CaC0a), fine powder is said to be easily recarbonated, and coarse powder is difficult to be recarbonated, as described above.

Furthermore, the collection efficiency of powder raw materials by the powder separator is very low for fine powders and very high for coarse powders, and when fine powders and coarse powders coexist, such as powder raw materials for cement, etc. Fine powders are not easily collected, therefore,
The fine powder will be circulated to the upper powder separator along with the exhaust gas from the powder separator. When the temperature of the powder raw material decreases in the upper stage, the fine powder absorbs carbon dioxide gas in the gas, causing a recarbonation reaction and generating heat, which increases the temperature of the exhaust gas from the preheating device. This may cause operational problems such as clogging of the powder raw material in the powder separator in the lower stage.

That is, in the above conventional example, the powder separators C, , C in the second stage from the bottom of the exhaust gas system preheating device 3 and the combustion gas system preheating device 4
, are both supplied to the calcining furnace 8 and partially calcined, and the lowermost heat exchange stages of the combustion gas system preheating device 4 and the exhaust gas system preheating device 3 are connected in series. A high degree of calcination is achieved through the passage.

However, the above powder raw material contains a mixture of fine grain powder and coarse grain powder, and in order to achieve a high degree of calcination for this internal phase grain powder, the lowermost heat exchange stages of the preheating devices of both systems are connected in series. For fine powder, passing through the lowest heat exchange stage of either the exhaust gas system preheater 3 or the combustion gas system preheater 4 is sufficient to achieve a high degree of calcination. This eliminates the need to pass through the bottom stage multiple times.

Therefore, in the conventional configuration described above, fine powder that is not easily collected by the powder separator also passes in series through the lowest heat exchange stages of the combustion gas system preheating device 4 and the exhaust gas system preheating device 3. , powder separator C24 and powder separator CI
The fine powder that cannot be completely collected in step 4 is circulated to the upper stage of the preheating device for both systems each time, and is passed through the lowermost stage multiple times, resulting in an extra pressure loss of the hot gas.
The amount of recarbonation due to the circulation of fine powder to the upper stage increases, which may impede thermal economy or cause operational problems.

(Objective of the Invention) The present invention has been made in view of the above-mentioned circumstances, and is capable of achieving a high degree of calcination of the coarse powder in the powder raw material in a preheating device, and also achieves a high degree of calcination of the coarse powder in the powder raw material. The purpose is to prevent an increase in pressure loss and recarbonation due to recirculation within the preheating device.

(Structure of the Invention) The present invention for achieving the above object is characterized by a powder separator located at the bottom of at least one of the preheating devices consisting of an exhaust gas system preheating device and a combustion gas system preheating device. is a classifier that classifies the powder raw material into fine powder and coarse powder, and the fine powder in the powder raw material passes through the lowermost powder separator of one preheating device, and the coarse powder The fine grain discharge port and the coarse grain discharge port of the classifier are respectively connected to the path of each preheating device so that the particles pass through the lowermost stage powder separator of the preheating device in series.

(Example) Hereinafter, the first to ninth embodiments of the present invention will be explained in Figs. 1 to 12.
This will be explained using figures. The basic configuration of each of the above embodiments is the same as that of the conventional example shown in FIG. Therefore, the same components are given the same reference numerals, and the explanation thereof will be omitted.

1 to 3 show a first embodiment.

In the figure, the lowest stage powder separator C'man in the combustion gas system preheating device 4 is a classifier that classifies the powder raw material into fine powder and coarse powder. This classifier is composed of a cyclone-shaped fine particle classifier 119 and a pocket-shaped coarse particle classifier 20 connected to this fine particle classifier 19. The above fine grain classification 4i! The fine particle discharge port 21 of 19 is the raw material chute 2
3 to the firing furnace 1, and the coarse particle discharge port 22 of the same coarse particle classifier 2o is connected to the gas inlet side gas duct 7a of the lowest stage powder separator C of the exhaust gas system preheating device 3 through the raw material chute 18. .

Then, the powder raw materials inputted from each raw material supply port 16.16 of the exhaust gas system preheating device 3 and the combustion gas system preheating device 4 are supplied to the calciner 8 from the powder separator 0 port and the powder separator C23. It absorbs the combustion heat of the fuel supplied from the fuel supply device 10 and is partially calcined. After passing through the inlet gas duct 7a of the powder separator C'24, this powder raw material is separated into fine powder and coarse powder by the powder separator C'24. The above-mentioned fine powder is put into the firing furnace l,
In addition, the coarse powder is removed from the powder separator C of the exhaust gas system preheating device 3.
The gas is introduced into the gas duct 7a on the inlet side of the heron.

In the case of the above structure, the fine powder can be highly calcined in the calciner 8 and the gas duct 7a on the inlet side of the powder separator C'24. On the other hand, the coarse powder is not sufficiently calcined in the calcination furnace 8 and the inlet side gas duct 7a of the powder separator C' prize, but continues to be calcined at the inlet side of the lowest stage powder separator CS4 in the exhaust gas system preheating device a3. A high degree of calcination is achieved in the gas duct) 7a.

Here, the powder separator C'24 will be explained.

This fine particle classifier 19 is shaped like a cyclone and has a cyclone body 25. This cyclone body 25 includes a cylindrical body 28 whose upper part is closed with a ceiling plate 27, and this cylindrical body 28.
8 and an inverted conical cylinder 29 connected to the lower end thereof, and the lower end of this inverted conical cylinder 29 serves as the fine particle discharge port 21. Further, a gas duct 17a which is a gas inlet is connected to the upper part of the cylindrical body 28 in a tangential direction or a circumferential direction, and a gas duct 7a which is a gas outlet is connected to the ceiling plate 27 almost coaxially with the cylindrical body 28. Connected.

Further, the coarse particle classification 41120 has a pocket portion 26 that communicates with the inner wall surface of the cylindrical body 28. Similar to the cyclone main body 25, this pocket part 26 is also formed of a cylindrical body 32 whose upper part is closed with a ceiling plate 31, and an inverted conical cylinder 33 connected to the lower end of this cylindrical body 32. The lower end of the cylindrical body 33 serves as the coarse particle outlet 22. Further, the cyclone main body 25 and the pocket portion 26 are communicated via a short pipe 34.

Further, an adjustment plate 37 is provided in the middle of the short pipe 34 to adjust the amount of coarse powder flowing from the fine classifier 19 to the coarse classifier Ia20. 38. 39 is the gate valve, raw material shoe) 23
．． This is opened and closed so as to block the passage of, for example, gas within 18.

And exhaust gas system preheating equipment! ! Powder raw material is fed into the calciner 8 from the powder separator C1l in the second stage from the bottom of the combustion gas system preheating device 4 via the raw material shoe) 15, and from the powder separator C23 in the second stage from the bottom of the combustion gas system preheating device 4. The powdered raw material that is introduced into the calciner 8 through the raw material chute 13 is
The powder raw material is then introduced into the gas duct h7a on the gas inlet side of the powder separator C'24, which is the classifier, and then introduced into the powder separator C'24 while exchanging heat with the gas. Then, the powder raw material along with the gas flows into the cylindrical body 2.
Rotate within 8. Then, due to the centrifugal force accompanying this rotation, the coarse powder passes through the inner hole of the short tube 34 provided on the inner wall surface of the cylindrical body 28 and is collected in the pocket portion 26, and then falls due to its own weight and becomes coarse. The grains are discharged from the grain discharge port 22.

On the other hand, since the centrifugal force is small, the fine powder swirls around the center of the cylindrical body 28, and therefore moves from the cylindrical body 28 side to the inverted conical cylinder 29 side without being collected in the pocket portion 26. Then, the gas in the swirling flow is reversed upward in the inverted conical cylinder 29, passes through the center of the swirling flow, and passes through the upper gas duct) 7.
It is discharged from a. Further, the fine powder in the swirling flow is subjected to a large centrifugal force due to the small radius of rotation within the inverted conical cylinder 29, and descends while swirling along the inner peripheral surface of the inverted conical cylinder 29, resulting in fine particles. It is discharged from the discharge port 21.

In the powder separator C'24 having the above configuration, this powder separator C'
Coarse powder is separated from the powder raw material by utilizing the swirling flow of hot gas introduced into '24. Therefore, coarse powder can be separated without increasing the pressure loss of the preheating device.

Moreover, since the coarse powder is separated from the powder raw material using the centrifugal force applied to the powder raw material when it rotates within the cyclone body 25, the separation efficiency of the coarse powder by the pocket portion 26 is high.

At this time, the amount of coarse powder collected into the pocket portion 26 via the short tube 34 can be adjusted as desired by adjusting the insertion length of the adjustment plate 37 provided on the short tube 34.

FIG. 4 shows a second embodiment, in which the short tube 3 of the powder separator c'
4 is rotatably provided with a vertically oriented pivot shaft 41, and a deflecting plate 42 is attached to this pivot shaft 41.

The amount of coarse powder collected in the pocket portion 26 is adjusted by rotating the warping plate 42 (indicated by a two-dot chain line in the figure).

FIG. 5 shows a third embodiment, in which a groove 43 extending along the outer peripheral surface of the cylinder 28 is formed on the upstream side of the gas swirling flow from the short pipe 34 in the cylinder 28 of the powder separator C'24. be done. A vertically oriented pivot shaft 44 is rotatably provided at the gas upstream end of the groove 43, and a deflection plate 45 is attached to this pivot shaft 44.

The amount of coarse powder collected in the pocket portion 26 is adjusted by 21 by rotating the warping plate 45 (as shown by the two-dot chain line in the figure).

FIG. 6 shows a fourth embodiment, in which a pocket portion 26 is provided on the side surface of the cylindrical body 28 below the gas introduction side gas duct 7a which is spirally connected to the cylindrical body 28 in the circumferential direction. With this configuration, the powder IK material is sufficiently urged toward the inner circumferential surface of the cylindrical body 28 by the centrifugal force due to the swirling flow.

Therefore, a sufficient amount of powder raw material can be collected in the pocket portion 26. Further, the arrangement position of the pocket portion 26 can be freely selected at a position relative to the gas duct 7a in the circumferential direction on the side surface of the cylindrical body 28 without interfering with the gas duct 7a.

Therefore, by arranging the pocket portion 26 on the side surface closer to the exhaust gas system preheating device 3, the exhaust gas system preheating device 3
You can easily connect with

FIG. 7 shows a fifth embodiment, in which a pocket portion 26 is provided on the side surface of an inverted conical cylinder 29 of a powder separator C'24. In addition, the same effect as in the above embodiment can be obtained even if the pocket portion 26 is provided spanning from the cylindrical body 28 to the inverted conical cylinder 29. Therefore, it is possible to adjust the amount and particle size distribution of the powder raw material to be separated, depending on the height position of the powder separator at which the pocket portion 26 is provided.

In addition to the locations shown in the above embodiments, the pocket portion 26 may be provided at any location in the vertical direction or circumferential direction as long as it is a side wall of the cyclone-like powder separator.

8 and 9 show a sixth embodiment, in which the pocket portion 26
A short-circuit gas duct 47 penetrates the ceiling plate 31 and connects the pocket portion 26 and the gas duct 7a on the gas discharge port side.
is provided.

A damper 48 is provided in the middle of the short-circuit gas duct 47. With this configuration, the short tube 34. Since a gas flow is generated that flows to the pocket part 26, the short-circuit gas duct 47, and the outlet side gas duct 7a, it is possible to improve the separation efficiency of the coarse powder to the pocket part 26, and also to separate the cyclone-shaped powder according to the amount of short-circuit gas. The pressure loss of the separator can be reduced. At this time, the amount of short circuit gas is controlled to an appropriate amount by the damper 48.

Further, the short pipe 34 connecting the cyclone main body 25 of the fine particle classifier 41319 and the pocket section 26 of the coarse particle classifier 20 is connected to the cylindrical body 32 of the pocket section 26 substantially tangentially or circumferentially. . Therefore, the exhaust gas becomes a swirling flow in the pocket portion 26 as in the cyclone body 25, and the gas is reversed upward in the inverted conical cylinder 33. Therefore, the short-circuit gas discharged through the short-circuit gas duct 47 The amount of powdered raw material that is accompanied by this and escapes from the pocket portion 26 to the gas duct 7a on the gas discharge port side can be minimized.

FIG. 10 shows a seventh embodiment, in which the powder separator C' in the second stage from the bottom in the exhaust gas system preheating device 3 and the powder separator C'23 in the second stage from the bottom in the combustion gas system preheating device 4
These are classifiers, each of which is comprised of a fine classifier 19 and a coarse classifier 20. The fine particle discharge port 21 of the fine particle classification l119 of the powder separator C'n is connected to the calciner 8 through the raw material chute 15, and the coarse particle classification @20
The coarse particle discharge port 22 is connected to the gas duct 7a on the gas inlet side of the powder separator Cs4 at the lowest stage by a raw material chute 50. Further, the powder discharge port of the powder separator C'm is connected to the intermediate part of the raw material chute 15 from the fine grain discharge port 21 of the fine grain classifier 19 of the powder separator C'm by another raw material chute 51.

On the other hand, to explain the powder separator C'23, the fine particle discharge port 21 of the fine particle classifier 19 is connected to the calciner 8 through the raw material chute 13, and the coarse particle The discharge port 22 is connected to the powder separator C evening gas inlet side gas duct 7a of the exhaust gas system preheating device 3 by a raw material chute 53. For this reason, each raw material supply port 16.16 of the exhaust gas system preheating device 3 and the combustion gas system preheating device 4 is
The powder raw material inputted from the bottom of each system preheating device
The powder is classified into fine powder and coarse powder by the powder separator C'u + C'23 in the third stage.

Then, the fine powder is directly put into the calcining furnace 8,
On the other hand, the coarse powder is fed into the calciner 8 of the combustion gas system preheater 4 via the powder separator C at the lowest stage of the exhaust gas system preheater 3. At this time, by adjusting the amount of coarse powder fed from the two-system preheating device to the powder separator C and into the calciner 8 through the raw material chute 50.53, the thermal work in the two-system preheating device 3.4 is adjusted. balance can be achieved. In addition, the powder separator C′ day coarse particle classification Ja20 in the exhaust gas system preheating device 3 and the combustion gas system preheating device 4
The coarse powder from the coarse classifier 20 of the powder separator C' is transferred to the gas inlet side gas duct (7a) of the powder separator CI4.
The coarse powder is pre-calcined in this duct 7a.Then, the coarse powder and the powder separator c',
, c′, from the fine classifiers 19, 19 are both highly calcined in the calciner 8. Therefore, fine powder that is not easily collected passes only through the lowest powder separator C24 of the combustion gas system preheating device 4 without passing through the lowest powder separator CS4 of the exhaust gas system preheating device 3. Therefore, the amount of circulation to the powder separator in the upper stage of the exhaust gas system preheating device 3 becomes small.

FIG. 11 shows the eighth embodiment, in which the powder separator C'9 in the second stage from the bottom in the exhaust gas system preheating device 3 and the powder separator C'9 in the lowest stage in the combustion gas system preheating device 4 are classified. 19 fine particle classifier and 20 coarse particle classifier, respectively.
It consists of

Fine grain discharge port 2 of the fine grain classifier 19 recommended by the powder separator C'
1 is connected to the firing furnace l through a raw material chute 23, and the coarse grain discharge port 22 of the coarse grain classifier 20 is connected to the powder separator CS4 of the exhaust gas system preheating device 3 through the raw material chute 18.
It is connected to the gas inlet side gas duct 7a. On the other hand, the fine particle discharge port 21 of the fine particle classifier 19 at the port of the powder separator C'
is connected to the middle part of the raw material chute 18 from the coarse grain classification @20 of the powder separator C'24 through the raw material shoe) 50, and the coarse grain outlet 22 of the coarse grain classifier 20 is connected to the raw material shoe) 15. is connected to the calciner 8 of the combustion gas system preheating device 4.

In addition, the gas duct on the gas inlet side of the powder separator C) 7
Another calcining furnace 55 is interposed between the powder separator C' and the coarse particle discharge port 22 of the coarse particle classifier 20 of the powder separator C'. An exhaust air duct 56 for supplying exhaust air from the device 2 is connected, and an independent fuel supply device 57 is provided to this calciner 55.

And exhaust gas system preheating device 3. The fine powder in the powder raw material inputted from the raw material supply port 16.16 of the combustion gas system preheating device 4 is sent to the fine grain classifier 19 of the powder separator C'o, the calcination furnace 55, powder separator c
I4. As well as flowing into the firing furnace 1, the combustion gas system preheating device 4 includes a powder separator C23, a calcining furnace 8, and a powder separator C.
'24 fine grain classifier 19 and firing furnace l. In addition, the coarse powder is transferred from the coarse particle classifier 20 of the powder separator C′ group and the powder separator c73 to the calcination furnace 8, the coarse particle classification @20 of the powder separator C′ group, the other calcination furnace 55, and the powder It is discharged to the firing furnace l via the separator CI4.

Therefore, the fine powder in the powder raw material input from the raw material supply port 16 of the exhaust gas system preheating device 3 is highly calcined while passing only through the calcination furnace 55 at the lowest stage of the exhaust gas system preheating device 3. At the same time, the fine powder in the powder raw material fed from the raw material supply port 16 of the combustion gas system preheating device 4 is highly calcined while passing only through the calciner 8 at the lowest stage of the combustion gas system preheating device 4. Baking is achieved. Further, the coarse powder in the powder raw materials preheated by the exhaust gas system preheating device 3 and the combustion gas system preheating device 4 was partially calcined in the calcination furnace 8 at the bottom stage of the combustion gas system preheating device 4. Thereafter, a high degree of calcination is achieved in the lowermost stage calcination furnace 55 of the exhaust gas system preheating device R3.

In this embodiment, a large amount of thermal work can be taken at the lowest stage of the exhaust gas system preheating device 3, but depending on the degree of distribution of the thermal work, the powder separator C can be used instead of providing the calciner 55.
It is sufficient to simply attach a fuel supply device to the gas inlet side gas duct) 7a of I4, and instead of the exhaust air duct 56, it is possible to cool the combustion air in the gas inlet side gas duct) 7a of the powder separator C. Even if the material is supplied from the device 2 through the firing furnace 1, the same effect as in the above embodiment can be obtained.

FIG. 12 shows a ninth embodiment, in which the powder separator C' port in the second stage from the bottom in the exhaust gas system preheating device 3 is used as a classifier, and a fine particle classifier 19 and a coarse particle classifier 2'0 are used as a classifier. configured. The fine particle discharge port 21 of the fine particle classifier 19 is connected to the gas inlet side gas duct 7a of the powder separator CI4 through a raw material chute 50, and the coarse particle discharge port 22 of the coarse particle classification a20 is connected to the raw material chute 15. It is connected to the calcining furnace 8 by.

Then, the powder raw material inputted from the raw material supply port 16 of the exhaust gas system preheating device 3 is classified into fine powder and coarse powder at the powder separator c' port, and the fine powder is transferred to the exhaust gas system preheating device 3. It passes only through the gas duct 7 on the gas inlet side of the powder separator C, which is the lowest stage, and is discharged to the firing furnace 1. Further, the coarse powder is supplied from the coarse grain classifier @20 to the calcining furnace 8, and from the calcining furnace 8, it is discharged to the calcining furnace 1 through powder separators C24 and CI4.

Therefore, the fine powder can be calcined to a high degree simply by passing through the gas duct 7a on the gas inlet side of the powder separator C of the exhaust gas system preheating device 3.

In addition, the above-mentioned coarse powder is partially calcined in the calcining furnace 8 together with the powder raw material inputted from the raw material supply port 16 of the combustion gas system preheating device 4, and then, after that, the coarse powder is partially calcined in the calcining furnace 8, and then the gas duct on the gas inlet side of the powder separator CSa) In 7a, a high degree of calcination is achieved with the fine-grained powder.

Incidentally, the passage order of the coarse powder in the powder raw material that passes through multiple systems in series is the lowest heat exchange stage of the combustion gas system preheating device 4 as in the first, eighth, and ninth embodiments. From this, the order of the lowest heat exchange stage of the exhaust gas system preheating device 3 is determined.
Alternatively, as in the seventh embodiment, contrary to the above, the order can be freely selected from the lowest heat exchange stage of the exhaust gas system preheating device 3 to the lowest heat exchange stage of the combustion gas system preheating device 4. Further, if necessary, the fine powder and the coarse powder can be combined in a raw material chute, mixed in advance, and then guided to the firing furnace 1.

In the above explanation, the number of preheating devices forming each system of the exhaust gas system preheating device 3 and the combustion gas non-system preheating device 4, the type and number of stages of the powder separator forming each preheating device, and the coarse powder The type of powder separator for separating fine powder and fine powder is not limited to the above embodiment.

(Effects of the Invention) According to the present invention, the powder separator located at the lower part of at least one of the preheating devices consisting of the exhaust gas system preheating device and the combustion gas system preheating device is used to separate powder raw materials into fine powder and coarse powder. In addition to being a classifier for classifying into granular powder, the fine powder in the powder raw material passes through the lowermost powder separator of each preheating device, and the coarse powder passes through the lowermost powder separator of each preheating device. Since the fine particle outlet and coarse particle outlet of the classifier were connected to the paths of each preheating device so that the particles passed in series, the fine particle powder passed through the two lowest heat exchange stages of one preheating device. Then, it is put into a firing furnace. Therefore, the above-mentioned fine powder is prevented from circulating in other preheating devices, and an increase in pressure loss and recarbonation in this preheating device can be prevented, and these exhaust gas system preheating devices and combustion The operational efficiency of a multi-system preheating device consisting of a gas system preheating device can be improved.

In addition, coarse powder, which requires a long residence time for calcination, passes in series through the lowermost heat exchange stage of both the exhaust gas system preheater and the combustion gas system preheater. During the passage, a high degree of calcination of the coarse powder can be achieved.

[Brief explanation of drawings]

Figures 1 to 12 show embodiments of the present invention, Figures 1 to 3 are the first embodiment, Figure 1 is a system diagram of a cement raw material firing device, and Figure 2 is a classifier. A side view of the powder separator, FIG. 3 is a partially cutaway view taken along the m-ttr line in FIG. 2, and FIG. 4 is a view corresponding to the broken part in FIG. Figure 5 is the third embodiment and corresponds to Figure 3, Figure 6 is the fourth embodiment and corresponds to Figure 2, and Figure 7 is the fifth embodiment and corresponds to Figure 2. Figures 8 and 9
The figures show the sixth embodiment, and Fig. 8 corresponds to Fig. 2. Fig. 9 corresponds to Fig. 3. Fig. 10 shows the seventh embodiment and corresponds to Fig. 1. The figure shows the eighth embodiment and corresponds to FIG. 1, FIG. 12 shows the ninth embodiment and corresponds to FIG. 1, and FIG. 13 shows the conventional example and corresponds to FIG. 1. . l.. Calcining furnace, 2.. Cooling device, 3.. Exhaust gas system preheating device, 4.. Combustion gas system preheating device, 7a.. Gas duct, 8. φ calcining furnace, 10.. Fuel supply device, 13- - Raw material chute, 14 - Raw material chute, 15 - Raw material chute, 18 - Raw material chute, 19 - Fine particle classifier, 2
0...Coarse particle classifier, 21...Fine particle discharge port, 22...Coarse particle discharge port, 23.Working material chute, 25..Cyclone body, 26..Pocket portion, 50..Material chute, 51
Warsha raw material chute, 53, working raw material chute, 55... calciner, No. 57, fuel supply device, CH-Cy4, (2
+-(24*e powder separator, C'mouth, c', c'man... powder separator.

Claims (1)

[Claims] 1. A firing furnace for firing powder raw materials, a cooling device for cooling the fired product discharged from the firing furnace with air flow, and an exhaust gas system for preheating the powder raw materials with exhaust gas from the firing furnace. A preheating device and a combustion gas system preheating device for combusting fuel using the exhaust air from the cooling device and preheating the powder raw material with the combustion gas are provided, and each of the preheating devices are stacked vertically and connected to each other. each having a plurality of connected powder separator groups, the powder discharge port of the lowest stage powder separator of at least one preheating device is connected to the firing furnace, while the combustion gas system is located at the lowest stage of the combustion gas system preheating device; A calciner that preheats powder raw materials by burning fuel using exhaust air from a cooling device between the gas inlet of a powder separator and the powder outlet of another powder separator above this powder separator. In the powder raw material firing apparatus, the powder separator located at the bottom of at least one of the preheating devices is used as a classifier for classifying the powder raw material into fine powder and coarse powder. The fine powder of the classifier is adjusted so that the fine powder in the raw material passes through the lowermost powder separator of one preheating device, and the coarse powder passes through the lowermost powder separator of each preheating device in series. A multi-system powder raw material preheating device characterized in that a grain discharge port and a coarse grain discharge port are respectively connected to the paths of each preheating device. 2. The classifier is composed of a cyclone-like fine-grain classifier and a pocket-shaped coarse-grain classifier formed outside the fine-grain classifier and communicating with the inner wall surface of the fine-grain classifier. A multi-system type powder raw material preheating device according to claim 1. 3. Claims 1 or 2, characterized in that a calciner equipped with an independent fuel supply device is provided on the gas inlet side of the powder separator at the lowest stage of the exhaust gas system preheating device. The multi-system type powder raw material preheating device described above.