JPH0717413B2 - Cement clinker firing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for firing cement clinker using a fluidized bed furnace.

[0002]

2. Description of the Related Art As a baking apparatus of this kind, Japanese Patent Application Laid-Open No. 62-2
As described in Japanese Patent No. 30657, a cement raw material powder preheated by a preheating means such as a suspension preheater is put into a spouted bed granulating furnace for granulation, and this granulated product is provided on the downstream side of the spouted bed granulating furnace. A cement clinker calcination device has been proposed in which the clinker is supplied to a fluidized bed calcination furnace connected to the calcination and calcinated, and the cement clinker as a calcined product is cooled and recovered by a fluidized bed cooling device.

In the above-mentioned firing apparatus, since coating is likely to occur especially in the freeboard portion of the fluidized bed firing furnace, it is necessary to prevent the occurrence of coating. One of the prevention devices is JP-A-61-161. As described in Japanese Patent No. 270244, there is proposed a device for introducing medium temperature air used for cooling a cement clinker in a multi-chamber fluidized bed cooler into a freeboard portion of a fluidized bed firing furnace. In the case of the same apparatus, the duct 21 'for discharging air after heat recovery from the multi-chamber fluidized bed cooler 8'is in the direction normal to the cylindrical side wall 7b of the fluidized bed firing furnace 7', as shown in FIG. (In the radial direction of the furnace 7).

[0004]

However, the prior art described in the above publication has room for improvement in the following points.

The former (Japanese Patent Laid-Open No. 62-230657)
Since the apparatus of (1) is a combination of a spouted bed granulation furnace and a fluidized bed firing furnace, when the flow velocity decreases, the granulated product or cement raw material powder may fall from the opening of the throat of the spouted bed granulation furnace. However, if the flow rate is increased too much, the amount of cement raw material powder jumping out to the freeboard part will increase, operation will become unstable due to fine powder circulation, the growth of coaching will accelerate, and problems such as fuel consumption deterioration will occur. . Further, when the scale is increased, the problem of falling or popping out of the granulated material or cement raw material powder becomes more serious.

The latter (Japanese Patent Laid-Open No. 61-270244)
In the above apparatus, since the main flow of cooling air that is heat-exchanged by the cooler is short-circuited to the lower end of the throat of the spouted bed granulation furnace, the temperature of the freeboard part of the firing furnace tends to cause coating.
There is a problem that the temperature is in the range of 50 to 1200 ° C. and coating occurs. Especially from the spouted bed type granulator
When changing to a fluidized bed granulation furnace in which there is no problem even if the flow velocity is reduced, as shown in FIG. 4, the coating A adheres to the inner peripheral wall of the throat 15 and the lower surface of the dispersion plate 16 having a porous structure, and as a result,
Increased ventilation resistance or loss of coaching may interfere with long-term continuous stable operation. In FIG. 4, 4'is a fluidized bed granulating furnace and 7'is a fluidized bed firing furnace.

The present invention has been made in view of the above points, and even when a fluidized bed furnace is used as the granulating furnace, coating is generated at various points including the throat below the granulating furnace and the lower surface of the dispersion plate. It is an object of the present invention to provide a cement clinker firing device capable of preventing the adhesion of the cement clinker and improving the granulation performance in the granulation furnace.

[0008]

Means for Solving the Problems To achieve the above object, a cement clinker firing apparatus of the present invention comprises: a) Injecting a cement raw material powder preheated by a preheating means such as a suspension preheater into a fluidized bed granulating furnace. Then, the granulated product is supplied to a cylindrical fluidized bed calcining furnace connected to the downstream side of the fluidized bed granulating furnace by a cylindrical throat and calcined to obtain a cement clinker as a calcined product. A cement clinker calcination device that cools and collects with a fluidized bed cooling device, b) a duct for discharging heat-exchanged air connected to an upper part of the fluidized bed cooling device, the cylindrical free of the fluidized bed calcination furnace The heat exchanged air is tangentially connected to the board portion or the throat so that the heat exchanged air flows in a swirling flow.

Further, as described in claim 2, c) a ventilation means having a variable flow rate is connected to a lower portion of the fluidized bed cooling device, and a temperature sensor is provided at or near the exhaust duct, and d) the heat is provided. It is preferable that the air flow rate can be adjusted so that the temperature of the exchanged air is 1000 ° C. or lower, preferably 800 to 900 ° C.

[0010]

According to the cement clinker calcination apparatus of the present invention having the above-mentioned structure, by the structure of a) above, the hot air introduced into the fluidized-bed granulating furnace through the throat from the top opening of the fluidized-bed calcination furnace Even if the flow velocity is reduced, the dispersion plate with a porous structure at the upper end of the throat prevents the granules and cement raw material powder from falling, and the flow velocity of the hot air is reduced to the freeboard part in the fluidized bed granulation furnace. The protrusion of cement raw material powder is greatly reduced.

Further, with the construction of b) above, the heat-exchanged air blown from the upper part of the cooling device through the discharge duct into the cylindrical freeboard part or throat of the fluidized bed firing furnace is the inner peripheral wall of the freeboard part or By swirling along the inner peripheral wall of the throat, the temperature in the vicinity of these inner peripheral walls is cooled to the temperature (1050 ° C.) or less at which the coating occurs. Note that the heat-exchanged air that has flowed into the freeboard section of the fluidized bed firing furnace swirls along the inner peripheral wall of the freeboard section, then swirls into the throat immediately above, and further flows into the inner peripheral wall of the throat. It swirls along and flows into the fluidized bed granulation furnace. On the other hand, the hot air rising in the fluidized bed firing furnace is introduced into the fluidized bed granulation furnace through the inside (center portion) of the swirling flow of the heat-exchanged air, but the temperature in the fluidized bed firing furnace is 1400. Since the temperature is as high as ℃ or higher, the central part of the throat and the central part of the dispersion plate continuous to it have a temperature of 1200 ° C. or higher with the hot air, so that there is almost a temperature range (1050 to 1200 ° C.) in which coating occurs. Will not do.

Further, with the above constitutions a) and b), the central part of the fluidized bed granulation furnace is in a high temperature region to promote the granulation of the cement raw material powder by melting and adhesion, and the peripheral part thereof. The (near the side peripheral wall) becomes a low temperature region, and the nucleation of the cement raw material powder is promoted. As a result, the granulation performance is improved and the control of the granulated particle size is facilitated.

According to the cement clinker calcination apparatus of the second aspect, by the constitutions of c) and d), the air blowing amount of the air pushed into the fluidized bed cooling device by the air blowing means is adjusted, The temperature of the heat-exchanged air exhausted from the upper exhaust duct can be lowered to 1000 ° C or lower. This action is very effective because the effect of preventing coating disappears when the temperature of the heat-exchanged air discharged from the fluidized bed cooling device becomes higher than 1050 ° C.
On the contrary, if the amount of air pushed into the fluidized-bed cooling device is increased too much and the temperature of the heat-exchanged air falls below 800 ° C., problems such as deterioration in fuel consumption occur. By maintaining the temperature in the range of 900 ° C., the heat (fuel consumption) efficiency is improved, and the effect of preventing the occurrence of coating and adhesion is sufficiently exerted.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cement clinker firing apparatus of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a flow sheet of a firing apparatus according to this embodiment, FIGS. 2 and 3 are sectional views taken along the line II--II of FIG.
It is a III-III sectional view taken on the line.

First, the system of the entire firing apparatus will be described with reference to FIG. 1 is a suspension preheater, and this suspension preheater 1 is a cyclone C ₁ C
It is composed of ₂ · C ₃ and C ₄ . The cement raw material powder fed into the system from the raw material feeding chute 3 is preheated through the cyclone C ₄ → the cyclone C ₃ → the cyclone C ₂ → the cyclone C ₁ and then fed into the fluidized bed granulating furnace 4. The granulated product granulated in the granulating furnace 4 is introduced into a fluidized bed calcining furnace 7 from an overflow chute 5 through an L valve (airtight discharging device) 6 and calcined in the fluidized bed calcining furnace 7. After that, it is thrown into the fluidized bed cooler 8 from the discharge chute 11 of the overflow structure, primary cooled there, then thrown into the packed bed cooler 9 from the discharge chute 12, secondary cooled there, and then recovered as cement clinker. .

The heat-exchanged air of the fluidized bed cooler 8 is connected and recovered to the upper end of the fluidized bed firing furnace 7 through the discharge duct 21, and the heat exchanged air of the packed bed cooler 9 is collected in the fluidized bed firing furnace. It is connected and collected to the wind box 10 of No. 7 through the exhaust duct 22. In the figure, 14a, 14b and 14c are heavy oil burners.

The fluidized bed granulation furnace 4 is composed of a cylindrical side wall 4b which constitutes a freeboard portion 4a and an inverted truncated cone portion (cone portion) 4c which is continuous thereunder. A lower end opening of the inverted truncated cone part 4c and a central opening of the upper end surface of the fluidized bed firing furnace 7 are connected by a throat 15, and a dispersion plate 16 having a perforated plate structure (pore diameter 20 to 100 mm) is provided in an upper part of the throat 15.
Is provided. A heavy oil burner 14a is provided slightly upward in the vicinity of the center of the upper surface of the dispersion plate 16,
A local high temperature region a is formed immediately above the center. On the other hand, a moving layer b in which the granules move downward is formed around the local high temperature area a in the inverted truncated cone portion 4c at a temperature lower than the local high temperature area a. In this way, the fluidized bed granulation furnace 4 is a fluidized bed furnace, but has a structure having a spouted bed function.

The other end of the preheated cement raw material powder supply pipe 18 having a pushing blower 17 at one end on the side wall of the inverted truncated cone portion 4c formed in the lower part of the fluidized bed granulation furnace 4 constructed as described above. Are connected. An ejector 19 is provided in the middle of the supply pipe 18, and a raw material powder supply chute 20 that is vertically provided on the cyclone C ₁ is connected to the ejector 19. Then, the raw material powder is blown into the moving layer b formed in the inverted truncated cone portion 4c by the pushing wind force action of the pushing blower 17, and the blown raw material powder is sufficiently diffused in the moving layer b and the local high temperature region is reached. It is guided by a.

The discharge duct 2 extending in an L-shape from the frustoconical upper end opening (discharge port) 8a of the fluidized bed cooler 8.
1 is connected to the cylindrical side wall 7b of the upper portion (freeboard portion) 7a of the fluidized bed firing furnace 7 in the tangential direction thereof as shown in FIG. In addition, the exhaust duct 2 near the exhaust port 8a
A temperature sensor 23 is provided in the unit 1. One end of an air supply pipe 25 is connected to the wind box 24 of the fluidized bed cooler 8,
A push-in blower 26 as a blowing means is connected to the other end, and a dispersion plate 8b is arranged at the upper end of the wind box 24. A flow rate control valve 27 is provided in the middle of the air supply pipe 25, and the flow rate control valve 27 and the temperature sensor 23 are connected.
Then, the detection signal from the temperature sensor 23 is sent to the flow control valve 27, and the set temperature value (for example, 800 to 900) is sent.
The opening degree of the valve 27 is automatically controlled so as to be (° C.). A push blower 28 is also connected to the packed bed cooler 9 via a flow rate adjusting valve 29.

Fluidized bed cooler 8 constructed as described above
Inside, the high temperature cement clinker C charged from the fluidized bed firing furnace 7 is heat-exchanged while being fluidized by the air blown into the wind box 24 and dispersed by the dispersion plate 8b. The heat-exchanged air passes through the discharge duct 21 and the fluidized bed firing furnace 7
It flows into the freeboard portion 7a of and rotates along the inner peripheral surface of the cylindrical side wall 7b. Since the temperature of the heat-exchanged air that swirls in this way is usually set in the range of 800 to 900 ° C., the periphery of the inner peripheral surface of the side wall 7b of the freeboard portion 7a is cooled to 1000 ° C. or less, and the coaching occurs. Is suppressed.

Further, by changing the granulating furnace to the fluidized bed granulating furnace 4 having the above structure, it is possible to reduce the flow velocity of the hot air introduced from the fluidized bed calcining furnace 7 without impairing the granulating property. As a result, the diameter of the throat 15 could be increased. As a result, the annular swirling bed in the low temperature region due to the relatively low temperature heat-exchanged air flowing in from the fluidized bed cooler 8 and the central layer in the high temperature region due to the hot hot air from the fluidized bed firing furnace 7 rising in the center thereof. And, separated into concentric double watershed layers with different temperatures, and each became a temperature region that suppresses the occurrence of coating. Moreover, in the fluidized bed granulation furnace 4,
The amount of the cement raw material powder and the fine clinker particles protruding to the freeboard portion 4a could be reduced.

Further, the fluidized air which has passed through the dispersion plate 16 and flows into the fluidized bed granulation furnace 4 has a double temperature structure of the annular swirling layer in the low temperature region and the central layer in the high temperature region as described above. Therefore, by further increasing the temperature of the local high temperature region a at the center when flowing into the fluidized bed granulation furnace 7, granulation of the cement raw material powder by melting and adhesion is promoted, and By lowering the temperature of the moving bed b, nucleation of the cement raw material powder is promoted and the granulation performance is improved.

Next, FIG. 3 shows another embodiment of the cement clinker firing apparatus of the present invention. The difference from the above embodiment is that the discharge duct 21 of the fluidized bed cooler 8 is connected to the throat 15. That is the connection. But throat 15
Other configurations including the basic configuration such as connecting to the cylindrical peripheral wall in the tangential direction so as to generate a swirling flow are common, and description thereof will be omitted.

In the case of the present embodiment, the relatively low temperature heat-exchanged air from the fluidized bed cooler 8 flows into the throat 15 and rises while swirling along the inner peripheral wall of the throat 15 to cause the throat 15 to move. The inner peripheral wall, the vicinity thereof, and the peripheral portion of the dispersion plate 16 are cooled to 1000 ° C. or less, and the occurrence of coating is suppressed. Note that the hot air from the fluidized bed firing furnace 7 rises in the central portion of the annular swirl bed due to the above-mentioned low-temperature heat-exchanged air, as in the above-mentioned embodiment.

Although not shown in the drawings, in the above-described embodiment, if the flow rate of the forced air flow is adjusted by using, for example, an inverter type blower (including a fan) capable of adjusting the flow rate of the forced air, the flow rate control valve can be controlled. 27 becomes unnecessary.

[0027]

As is apparent from the above description,
The cement clinker firing apparatus of the present invention has the following effects.

(1) Since the cooling air blown from the cooling device into the cylindrical freeboard portion or throat of the firing furnace swirls along the inner peripheral wall, the vicinity of the inner peripheral wall is effectively cooled to the temperature below the coating generation temperature. Therefore, the occurrence of coaching is suppressed. Further, since hot hot air from the firing furnace flows through the central portion of the swirling cooling air, it is heated to a temperature higher than the coaching generation temperature, and similarly, the generation of coating is suppressed. Therefore, even when a fluidized bed furnace is used as the granulating furnace, it is possible to reliably prevent the occurrence of coating and its adhesion at various points including the throat below the granulating furnace and the lower surface of the dispersion plate, and to stabilize for a long period of time. Continuous operation becomes possible.

(2) Due to the effect of (1) above, the center portion of the fluidized bed granulation furnace has a high temperature region to promote the granulation of the cement raw material powder, and its peripheral portion (near the side peripheral wall). In the low temperature range, the nucleation of the cement raw material powder is promoted, so that the granulation performance is improved and the granulated particle size is easily controlled.

(3) By the effect of the above (2), the granulation performance of the cement raw material powder is improved and the throat diameter can be expanded, so that the effect of the above (1) is effectively exhibited, and the inner peripheral wall of the throat is coated. In addition to making it more difficult to adhere, the flow velocity of the fluidizing air (hot air) can be reduced, so the amount of fine clinker particles protruding to the freeboard part of the granulating furnace is reduced, stable operation is possible, and fuel efficiency is good. Become.

In the firing device according to the second aspect, the above (1) to
In addition to the effect of (3), the following effects can be obtained.

(4) The flow rate of air is controlled so that the temperature of the cooling air discharged from the cooling device is 1000 ° C. or lower,
Occurrence of coaching is suppressed. This temperature is 800
When the temperature is maintained in the range of up to 900 ° C, the heat (fuel consumption) efficiency is further improved, the effect of preventing the occurrence of coating and adhesion is sufficiently exerted, and economical long-term continuous stable operation becomes possible.

[Brief description of drawings]

FIG. 1 is a flow sheet showing an outline of a cement clinker firing apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

3 is a sectional view taken along line III-III in FIG. 1, showing another embodiment of the present invention.

FIG. 4 is a schematic view showing a part of a cement clinker firing device to which the prior art is applied.

5 is a sectional view taken along line VV of FIG.

[Explanation of symbols]

C ₁・ C ₂・ C ₃・ C ₄ Cyclone 1 Suspension preheater 3 Raw material injection chute 4 Fluidized bed granulation furnace 7 Fluidized bed firing furnace 8 Fluidized bed cooler 15 Throat 21 Exhaust duct 23 Temperature sensor 23 25 Air supply pipe 26 Indentation Blower 26 27 Flow control valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Ishibachi No. 1 Kanda Midoshiro-cho, Chiyoda-ku, Tokyo Sumitomo Cement Co., Ltd. (72) Inventor Isao Hashimoto 1-1 Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries Akashi Plant Co., Ltd. (72) Inventor Tatsuya Watanabe 1-1 Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries Ltd. Akashi Plant Co., Ltd. (72) Shozo Kanamori 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe City, Hyogo Prefecture No. Kawasaki Heavy Industries, Ltd.Kobe factory

Claims (2)

[Claims] 1. A cement raw material powder preheated by a preheating means such as a suspension preheater is charged into a fluidized bed granulating furnace to granulate, and the granulated product is provided at the lower end of the fluidized bed granulating furnace with a cylindrical throat. A cement clinker calcination device that is supplied to a cylindrical fluidized bed calcination furnace connected by calcination and calcined, and cools and recovers the cement clinker as a calcined product with a fluidized bed cooling device, wherein The exhaust duct for the heat-exchanged air connected to was connected tangentially to the cylindrical freeboard portion or the throat of the fluidized bed firing furnace so that the heat-exchanged air would flow in a swirling flow. A cement clinker firing device characterized by the above. 2. A variable-flow blower is connected to the lower part of the fluidized-bed cooling device, and a temperature sensor is provided at or near the exhaust duct, and the temperature of the heat-exchanged air is 1000 ° C. or lower, preferably The cement clinker calcination apparatus according to claim 1, wherein the air flow rate can be adjusted so as to be 800 to 900 ° C.