JPH031257B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cement clinker firing device,
Specifically, the present invention relates to a firing device that calcinates preheated cement raw material powder, granulates it, and collects and fires the granules. This is used in the field of technology to produce clinker through the steps of preheating, calcining, granulating, firing, and cooling cement raw material powder.

[Prior art]

For example, the production of cement clinker by firing cement raw material powder while granulating it is described in US Patent No.
It has been known for quite some time, as proposed in No. 2874950. This is because core clinker and cement raw material powder at room temperature are put into a fluidized bed furnace, and when the core clinker becomes semi-molten in the fluidized bed, the raw material powder adheres to it while it remains in the fluidized bed. The granulated material can be granulated and fired at the same time. Such equipment has very few moving parts, so it is expected that there will be few troubles during operation, and that it will be possible to increase the operating efficiency.

However, since granulation and calcination are performed simultaneously in one fluidized bed, granulation and calcination operations must be performed under one operating condition. the result,
It is difficult to set independent conditions suitable for each operation, resulting in variations in the degree of granulation, and insufficient calcination due to the long and short residence time of complete mixing, resulting in poor clinker quality. be. In addition, since the core clinker at room temperature is fluidized and raised to a temperature of around 1,300°C, which is suitable for granulation, it requires a large amount of energy and has low thermal efficiency, so it has not been realized on a commercial basis. .

To those who tried to solve this problem,
There is a fluidized bed furnace for granulation and firing described in Japanese Patent No. 32193. In addition to supplying fluidizing gas through a perforated plate for gas rectification, this furnace also supplies fuel to a fluidized bed to form a jet flow, making it possible to adjust particle size and calcination. It is. In addition, clinker is not used as the core for granulation, but a portion of cement raw material powder is granulated and dried in a fluidized bed granulator, and then it is granulated together with cement raw material powder in a fluidized bed. It is now supplied internally.

In such a fluidized bed furnace, as in the above-mentioned U.S. patent, granulation of the raw material powder and firing of the granules are performed in a completely mixed state, so optimizing one operation will lead to optimization of the other. It is difficult to maintain the best conditions for both operations. Therefore,
There is a problem in that the quality of the produced clinker varies, and furthermore, the energy required to raise the temperature of the core raw material particles cannot be ignored, and there is a limit to the reduction in fuel consumption.

[Purpose of the invention]

The present invention was developed in view of the above-mentioned problems, and its purpose is to enable the granulation operation of cement raw material powder and the firing operation of the granulated material to be performed independently, thereby optimizing each operation. Provides a cement clinker sintering device with a low total height that can generate high-quality clinker by reducing the consumption of thermal energy required for granulation and operate with high thermal efficiency. It is to be.

[Structure of the invention]

To explain the features of the present invention, as shown in FIG. 1, a furnace 3 for granulating cement raw material powder and a furnace 4 for firing the granules are provided independently, and
A core clinker input section 20 is provided for preheating core clinker for granulating raw material powder. The granulation furnace 3 is a spouted bed furnace, and an exhaust gas inlet 11 is opened in its upper body 3A to introduce the calciner exhaust gas after calcining cement raw material powder. Furthermore, a granulation material inlet 13 into which preheated nuclear clinker and calcined cement raw material powder are introduced is opened in the inverted conical portion 3B on the lower side of the granulation furnace 3, and a granulation material inlet 13 is opened in the vicinity of the inlet. A burner 14 is installed to heat the material to be granulated, and an exhaust gas inlet 15 for introducing the firing furnace exhaust gas is opened at the lower end, and the granulated material is discharged upward from the material input port 13. Outlet 1
7 is open. The firing furnace 4 is a fluidized bed furnace for firing granules in a fluidized bed 21, and is provided with a granule chute 24 that supplies the granules discharged from a granule outlet 17 to the fluidized bed. A firing furnace exhaust gas duct 26 that sends firing furnace exhaust gas to the exhaust gas inlet 15 is connected to the top. A calcining furnace 2 for calcining preheated cement raw material powder is provided via a throat 8 above the high temperature part of the fluidized bed cooler 5 that cools the calcined clinker.

Note that when nuclear clinker is not used, the nuclear clinker input section 20 is not provided, and the granulation furnace 3
Only the calcined cement raw material powder is fed into the lower inverted conical portion 3B.

〔Example〕

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is an overall view showing an embodiment of a cement clinker firing apparatus 6 mainly composed of a preheating section 1, a calcining furnace 2, a granulating furnace 3, a firing furnace 4, and a cooler 5. Clinker is produced by granulating and firing powder. The preheating section 1 is, for example, a floating heat exchanger consisting of a plurality of cyclones, and the cement raw material powder input from the raw material input port 7 is sequentially passed through the cyclones C4 and C3 while exchanging heat with the exhaust gas rising in each duct. ,C2,
It is collected by C1, descends, and is preheated to a predetermined temperature.

The calcining furnace 2 decarbonates the cement raw material powder heated in the preheating section 1 before inputting it into the granulation furnace 3.
This allows the granulated material to be fired more effectively. Although the calcining furnace is well known and will not be described in detail, it is installed on a cooler 5, which will be described later. The air for calcination is designed so that the exhaust gas from the cooler 5 is introduced through the throat 8.
An exhaust gas inlet 9 for this purpose is opened at the lower end of the calciner 2 .

The granulation furnace 3 is a furnace for granulating the cement raw material powder calcined in the calcination furnace 2, and in order to facilitate operations to enhance the granulation effect in the furnace, a granulation furnace is used to granulate the granulated material. It is provided independently of the furnace 4. This granulation furnace 3 is a spouted bed furnace that introduces firing furnace exhaust gas to form a spouted bed 10, and is composed of a body portion 3A and an inverted conical portion 3B formed below the body portion 3A.

An exhaust gas inlet 11 is opened in the upper body portion 3A, through which calciner exhaust gas is swirled and introduced after calcining preheated cement raw material powder in the calciner 2. A granulation material inlet 13 into which preheated nuclear clinker and calcined cement raw material powder are introduced is opened at the lower part of the lower inverted conical part 3B so as to form a hot spot 12. A suitable number of burners 14 for heating the material to be granulated are installed in the vicinity of the inlet, slanting slightly upward. An exhaust gas inlet 15 is opened at the lower end of the inverted conical portion 3B to introduce the firing furnace exhaust gas which serves as combustion air for the burner 14 and forms the above-mentioned spouted bed 10. In addition, on the side of the inverted conical part 3B or the body part 3A above the material input port 13, the granulated material, in which particles have grown by circulating in the spouted bed 10, is discharged to the firing furnace 4. A granulated material discharge port 17 is opened.

In the upper part of such a granulation furnace 3, granulation furnace exhaust gas 1
Granulation furnace exhaust gas duct 19 leading out 8 to the preheating section 1
is connected to this, and is provided with a nuclear clinker input section 20 into which, for example, nuclear clinker having a particle size of less than 1 mm is input for preheating. By preheating the nuclear clinker with the thermal energy contained in the granulation furnace exhaust gas 18 in this way, heat consumption in the granulation furnace 3 can be significantly suppressed. In addition, the input of nuclear clinker is
This is not limited to the granulation furnace exhaust gas duct 19, but can also be carried out at a location where it flows through all or part of the preheating section 1 like the cement raw material powder. selected.

The firing furnace 4 is a fluidized bed furnace that fires the granulated material in a fluidized bed 21, and the exhaust gas of the cooler that has passed through the cooler 5 to cool the clinker is passed through the fluidizing gas inlets 22 and 23 to cause the firing process. The gas is divided into a portion to be supplied to the chamber 4A and the ripening chamber 4B, and a portion to be supplied to the slow cooling chamber 4C, and the gas is introduced as a fluidizing gas in the firing furnace 4. In addition, the illustration shows 1 of each
It consists of three firing chambers, a ripening chamber, and an annealing chamber, but each chamber may be composed of a plurality of chambers. In such a firing furnace 4, a granule discharge port 17 of the granulation furnace 3 is provided.
A granule chute 24 is provided to supply the granules discharged from the granulator to the fluidized bed 21, and a calcination furnace exhaust gas duct 26 is provided above the furnace to send calcination furnace exhaust gas 25 to the exhaust gas inlet 15 of the granulation furnace 3. It is connected. The granulated material chute 24 is provided with a selective extraction gas blowing port 27 above the airtight discharger 28 for extracting only appropriately grown granulated material, so that the furnace gas is supplied. An in-furnace gas blowing duct 29 opened to the firing furnace 4 is connected to the firing furnace 4 . Note that the atmosphere can also be introduced as cold air from the air outlet 27.

The diameter of the fired clinker is about 1 to 2 mm, and in order to cool it, the cooler 5 is also connected to the firing furnace 4.
A fluidized bed similar to that used is used. The cooler 5 is divided into a high-temperature section 5A and a low-temperature section 5B, and cooling air is supplied and discharged from each section independently, and each section is multi-chambered. In this example, the exhaust gas in the high temperature section 5A is supplied to the above-mentioned calciner 2 via the throat 8, and the exhaust gas in the low temperature section 5B is
After the dust is removed by the dust collector 30, it is supplied to the fluidizing gas inlets 22 and 23 of the firing furnace 4.

The clinker discharged from the cooler 5 is carried out to the next process, and a part of it is used as core clinker. Therefore, a clinker crusher 31 and a screen 32 are installed, and the clinker is transported to the nuclear clinker input section 20 by a transporter (not shown) to ensure that the supply of nuclear clinker is not interrupted.

According to such an embodiment, as described below, the raw material powder can be granulated to a constant particle size, and the desired calcination can be performed, so that high quality clinker can be produced.

The cement raw material powder inputted from the raw material input port 7 exchanges heat with the exhaust gas rising through the duct 1a of the preheating section 1, and then is collected by the cyclone C4, and then transferred to the duct 1.
When the gas is put into b, it exchanges heat while floating in the rising exhaust gas. Such operations are repeated, and the raw material powder is calcined to a predetermined temperature while being sequentially transferred from the cyclones C3 and C2 to the calcining furnace 2. Note that the exhaust gas is discharged from the granulation furnace 3, and is discharged from the cyclone C1, which is opposite to the raw material powder, through the cyclone C4.

In the calcining furnace 2, 650 from the high temperature section 5A of the cooler 5
Exhaust gas at ~750°C is supplied through the throat 8, heated by burners 33 and 34, and then passed through the cyclone C.
The cement raw material powder from 2 is decarboxylated. In addition,
The gas whose apparent flow rate has increased due to heating is transferred to the constriction section 3.
The raw material powder accelerated in step 5 and calcined is introduced into the granulation furnace 3 from the calciner exhaust gas duct 36 along with the calciner exhaust gas.

On the other hand, when the clinker produced in the kiln 4 is cooled in the cooler 5 and carried out to the next process, a part of it is taken out and crushed in the clinker crusher 31. The particle size is adjusted to less than 1 mm by a screen 32, and the clinker is introduced from the nuclear clinker input section 20 provided in the exhaust gas duct 19 of the granulation furnace. This nuclear clinker exchanges heat while floating in the exhaust gas flowing through the duct 19, and is collected by the cyclone C1. The thus preheated nuclear clinker and calcined raw material powder are charged into a hot spot 12 at a temperature of 1250 to 1350°C through a granulation material inlet 13 opened at the bottom of the granulation furnace 3.

This part contains the firing furnace exhaust gas 25 from the firing furnace 4.
is supplied, and the fuel ejected from the burner 14 is combusted. As a result, the material to be granulated is rapidly heated and becomes a semi-molten state, and a spouted bed 10 is formed by the energy of combustion gas and firing furnace exhaust gas, and the core clinker circulates. During this time, the raw material powder adheres and the core clinker, which was less than 1 mm in size, grows into granules with a size of 1 to 2 mm. In such granulation, by adjusting the combustion amount of the burner 14, etc., operating conditions suitable for granulation can be achieved. Incidentally, the supplied firing furnace exhaust gas 25 has a temperature of at least 1250~
Since the temperature is 1300°C, melting of the material to be granulated is promoted. Moreover, relatively low-temperature exhaust gas from the calciner 2 is introduced into the body 3A from the exhaust gas inlet 11 in a tangential direction (see Figure 2), suppressing the adhesion of fine molten matter on the wall surface of the body 3A. At the same time, a swirl is given to the floating raw material powder and nuclear clinker. As a result, the raw material powder and core clinker are collected and fall onto the granule layer 16. They adhere to the granules,
Fusion and sticking between granules is also avoided. If the granulating furnace exhaust gas duct 19 of the granulating furnace 3 is installed offset from the furnace core, especially if the granulating furnace exhaust gas duct 19 is installed at a position around 41 in the figure, it will not be discharged along with the exhaust gas. This further reduces the amount of core clinker and raw material powder, which further promotes granulation.

The cement raw material grown to a predetermined size is supplied to the kiln 4 from the granule outlet 17 through the granule chute 24 . Fuel is supplied from the fuel supply device 37 and mixed with the granules. Cooler exhaust gas whose temperature has been raised by flowing through the cooler 5 is removed by a dust collector 30 and then supplied as a fluidizing gas to the firing furnace 4 from the fluidizing gas inlets 22 and 23. The temperature inside the firing furnace 4 is maintained at 1350 to 1450°C, and clinker is produced. Since this generation is carried out independently of the granulation operation, operating conditions are suitable for calcination and high quality clinker is produced.
The clinker fired in the firing chamber 4A overflows from the firing chamber 4A due to the granules successively introduced from the granule chute 24, and moves over the partition wall 38 to the ripening chamber 4B. The clinker aged in the same manner is transferred to the slow cooling chamber 4C and gradually cooled. When firing, aging, and slow cooling are performed in the firing furnace 4 in this manner, the quality of the clinker can be further improved compared to the case where the clinker is rapidly cooled in a cooler after firing.

The clinker discharged from the slow cooling chamber 4C of the kiln 4 is cooled down to a predetermined temperature while moving through several fluidized beds in the cooler 5.
The clinker is transported to the next final grinding process. Note that the diameter of the granules hardly changes during firing and cooling, and as mentioned above, the particle diameter is up to 2 mm, which is smaller than ordinary clinker, which is convenient because the unit consumption for pulverization is reduced.

Incidentally, the granulated material discharged from the granulation furnace 3 may contain particles with small particle sizes and raw material powder. If an appropriate amount of cold air or furnace gas from the firing furnace 4 is selectively supplied to the air outlet 27 of the granulated material chute 24 as shown in the figure, small-diameter particles will be blown back into the granulating furnace 3. Large-diameter particles with a high degree of granulation are supplied to the firing furnace 4. If such air blowing is not performed, fine particles that have reached the firing furnace 4 will fly out of the fluidized bed 21,
It is returned to the granulation furnace 3 through the exhaust gas inlet 15 along with the firing furnace exhaust gas.

Note that the temperature of the gas flowing through the calciner exhaust gas duct 36 is high, so if a part of the preheated raw material powder in the cyclone C2 of the preheating section 1 is supplied from the raw material powder supply port 39, the amount of raw material powder can be increased and Exhaust gas temperature can be lowered.

FIG. 3 shows a different example of the granulation furnace 3, in which a constriction part 40 is formed in the body 3A, and a granulation furnace exhaust gas duct 19 is provided in the furnace core. The flow rate of the rising granulation furnace exhaust gas is increased by this constriction part 40, so that the nuclear clinker and raw material powder floating in the furnace can be quickly removed. According to this, it is possible to suppress the mixing of fine powder and fine grains into the granulated material discharged from the granulated material discharge port 17. As a result, operations such as selection drawer in the granule chute 24 can be omitted. Note that the air volume increases due to the calciner exhaust gas at 800 to 850°C introduced from the exhaust gas inlet 11, and the flow velocity passing through the throttle part 40 becomes higher.
Not only can the above-mentioned effects be enhanced, but also the exhaust gas temperature can be lowered and adhesion in the granulation furnace exhaust gas duct 19 can be suppressed.

In each of the above examples, a spouted bed was used instead of a fluidized bed for the granulation operation. The spouted bed furnace has the advantage of a simple structure because it does not require a wind box for fluidizing gas or a distribution plate that requires heat resistance in a fluidized bed furnace. In addition, by using a core clinker with a high adhesion rate of raw material powder, and by preheating the core clinker to a desired temperature before granulation, it is possible to improve granulation performance.

What should be noted about the above-described apparatus is that the high-temperature sintering furnace exhaust gas is supplied to the granulation furnace 3, and the low-temperature exhaust gas from the cooler 5 is supplied to the calcination furnace 2.
Therefore, raising the temperature at the hot spot 12 of the granulation furnace 3 to about 1700 to 1800 DEG C. can be carried out without much difficulty. Therefore, granulation can be achieved by melting the raw material powder without using a core clinker that facilitates granulation. Therefore, it is possible to realize a clinker firing apparatus that performs firing after granulation without providing the core clinker input section in the apparatus described above.

〔Effect of the invention〕

As explained in detail above, the present invention uses different furnaces for granulation and calcination to produce cement clinker, and granulation is performed by a spouted bed while calcination is performed by a fluidized bed. , it becomes easy to set and adjust each operating condition, and it is possible to achieve granulation with uniform particle size and complete firing at the optimum temperature. Furthermore, since the preheated raw material powder is calcined in the calcining furnace, the firing capacity of the calcining furnace can be reduced.

When using nuclear clinker, granulation properties are good;
Since the core clinker is preheated using the granulation furnace exhaust gas and then subjected to granulation, the granulation can be performed smoothly and the thermal energy consumption can be reduced.

The granulation furnace is installed above the calcination furnace, and the calcination furnace is installed above the cooler, so they are arranged in parallel, significantly reducing the total height compared to when the calcination furnace is installed above the granulation furnace. Can be done.

[Brief explanation of the drawing]

FIG. 1 is an overall view of one embodiment of the cement clinker firing apparatus of the present invention, FIG. 2 is a sectional view taken along the line -- in FIG. 1, and FIG. 3 is a different example of the granulation furnace. 2... Calcination furnace, 3... Granulation furnace, 3A... Body part,
3B... Inverted conical part, 4... Firing furnace, 5... Cooler, 8... Throat, 11... Exhaust gas inlet, 1
3... Granulation material inlet, 14... Burner, 15...
... Exhaust gas inlet, 17... Granule discharge port, 19...
... Granulation furnace exhaust gas duct, 20 ... Nuclear clinker input section, 21 ... Fluidized bed, 24 ... Granule chute,
26... Firing furnace exhaust gas duct, 27... Ventilation port,
29...Furnace gas ventilation duct.

Claims (1)

[Claims] 1. In an apparatus for producing cement clinker by granulating and firing preheated cement raw material powder, the furnace for granulating the cement raw material powder and the furnace for firing the granules are independently provided. At the same time, a nuclear clinker input part is provided for preheating the nuclear clinker for granulating the raw material powder, and the granulation furnace is a spouted bed furnace, and the upper body of the granulating furnace is used for calcination of the cement raw material powder. The exhaust gas inlet into which the calciner exhaust gas is introduced is opened almost tangentially, and the inverted cone-shaped part below it is fed with preheated nuclear clinker and calcined cement raw material powder. A granulated material inlet is opened, a burner for heating the granulated material is installed near the inlet, and an exhaust gas inlet for introducing firing furnace exhaust gas is opened at the lower end of the granulated material inlet. A granule discharge port for discharging the granules is opened upward, and the firing furnace is a fluidized bed furnace for firing the granules in a fluidized bed, and the granules discharged from the granules discharge port are A granule chute is provided to supply the material to the fluidized bed, and a firing furnace exhaust gas duct is connected above the furnace to send the firing furnace exhaust gas to the exhaust gas inlet, and the high temperature of the fluidized bed cooler that cools the fired clinker is connected to the furnace. A cement clinker firing apparatus characterized in that a calcining furnace for calcining preheated cement raw material powder is installed on the top of the unit through a throat. 2. The cement clinker firing apparatus according to claim 1, wherein the nuclear clinker input section is provided in a granulation furnace exhaust gas duct of a granulation furnace. 3. The cement clinker firing apparatus according to claim 1, wherein the granule chute is provided with a gas outlet for selectively drawing out the granules. 4. The cement clinker firing apparatus according to claim 3, wherein the blast opening is connected to an in-furnace gas ventilation duct that opens into the firing furnace. 5 In an apparatus for producing cement clinker by granulating and firing preheated cement raw material powder, a furnace for granulating the cement raw material powder and a furnace for firing the granules are provided independently, and the granulation The furnace is a spouted bed furnace, and an exhaust gas inlet is opened almost tangentially in the upper body of the furnace, through which the exhaust gas from the calciner after calcining the cement raw material powder is introduced, and an inverted conical inlet is opened in the lower part of the body. A granulation material inlet is opened in the shaped part, into which the calcined cement raw material powder is input, a burner is installed near the input port to heat the granulation material, and the kiln exhaust gas is introduced into the lower end. An exhaust gas inlet is opened, a granulated material discharge port for discharging the granulated material above the granulated material input port is opened, and the firing furnace is a fluidized bed furnace for firing the granulated material in a fluidized bed. A granule chute is provided to supply the granules discharged from the granule outlet to the fluidized bed, and a firing furnace exhaust gas duct is connected above the furnace to send the firing furnace exhaust gas to the exhaust gas inlet. A calcining furnace for calcining preheated cement raw material powder is installed through a throat above the high temperature part of a fluidized bed cooler that cools the calcined clinker. Baking equipment.