JPS61136945A - Method and equipments for burning cement clinker - 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] [Field of Industrial Application] The present invention relates to a method and apparatus for firing cement clinker, and more specifically, to granulating cement raw material powder using preheated core clinker and producing the granulated product. The present invention relates to a firing method and apparatus for firing together. This is used in the field of technology in which cement raw material powder is preheated and calcined, then granulated, fired, and cooled to produce clinker.

[Prior art]

The production of cement clinker by firing cement raw material powder while granulating it is disclosed in, for example, U.S. Patent No. 2.874,9.
As proposed in No. 50, it has been known for quite some time. 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, resulting in granulation. The granules can be 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. As a 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 length of residence time due to complete mixing, resulting in deterioration of clinker quality. There is a problem.

In addition, since the core tarinka at room temperature is raised to a temperature of around 1,300° C. that enables granulation without fluidizing it, there is a problem that a large amount of energy is required and thermal efficiency is low, so this method has not been realized on a commercial basis.

The person who tried to solve this problem was
There is a fluidized bed furnace for granulation and firing described in Publication No. 3. 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 stream, 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 designed to be 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 material particles is negligible, and there is a limit to the reduction in fuel consumption.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and its purpose is to:
The granulation operation of the cement raw material powder and the calcination operation of the granules can be performed independently, making it possible to optimize each operation and produce high-quality clinker. An object of the present invention is to provide a cement clinker firing method and apparatus that can suppress the consumption of thermal energy required for grains and operate with high thermal efficiency.

[Structure of the invention]

To explain the present invention in detail, in the invention of the method, preheated nuclear clinker is made into a high temperature semi-molten state by heating the clinker, and a fluidized flue gas is supplied thereto to form a spouted bed. , supplying the preheated cement raw material powder to the high temperature semi-melting section after calcining it using granulation furnace exhaust gas;
The cement raw material powder is attached to the core clinker to granulate the cement raw material, and the granules are collected and fired in a fluidized bed.

In addition, in the invention of the device, as shown in FIG. 3 and a calcining furnace 2 for calcining the preheated raw material powder are integrally formed above and below. The granulation furnace 3 is a spouted bed furnace, and a granulation material inlet 16 is opened in the lower part thereof, into which preheated nuclear clinker and calcined cement raw material powder are introduced. A burner 17 is installed to heat the material to be granulated, and an exhaust gas inlet 19 is opened at the lower end to introduce fluidized exhaust gas from the firing furnace, and the granulated material is discharged upward from the material input port 16. A material discharge port 21 is opened. The firing furnace 4 is the firing chamber 4
A is a fluidized bed furnace that has a maturing chamber 4B and a slow cooling chamber 4C and fires granules in a fluidized bed, and supplies the granules discharged from the granules discharge port 21 to the firing chamber 4A. A granule chute 25 is provided, and a riser pipe 27 is connected to the calcination furnace 2 for sending fluidized exhaust gas to the exhaust gas inlet 8 of the calcination furnace 2 .

〔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. After calcining the powder, it is granulated and fired to produce clinker. 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 lower passes through the cyclones C4 and C3° while exchanging heat with the exhaust gas rising in each duct. C
2. It is collected by C1, descends, and is preheated to a predetermined temperature.

The calcination furnace 2 decarboxylates the cement raw material powder heated in the preheating section 1 before charging it into the granulation furnace 3, so that the granules can be fired more effectively. Since the calcining furnace is well known, a detailed explanation thereof will be omitted, but it is integrally formed above and below the granulation furnace 3 described below. Since the calcination air is intended to be used as a fluidized exhaust gas from the calcination furnace, which will be described later, an exhaust gas inlet 8 is provided for this purpose.

As shown in FIG. 2, this exhaust gas inlet 8 is opened almost in the tangential direction of the calciner 2, and a constriction part 9 is provided at the bottom of the exhaust gas inlet 8.
is formed, and the flow rate of the granulation furnace exhaust gas rising therein is increased, and an appropriate number of burners 10 as shown in Fig. 3 are installed in the tangential direction at that point to generate higher temperature calcining gas. It is planned.

In the upper part of the calciner 2, there is a calciner exhaust gas duct 1 that leads the calciner exhaust gas 11 (see Fig. 4) to the preheating section 1.
2 is connected to this, and is provided with a nuclear clinker inlet 13 into which, for example, nuclear clinker having a diameter of less than 1 mm is input for preheating. By preheating the nuclear clinker with the thermal energy contained in the calciner exhaust gas in this manner, heat consumption in the granulation furnace 3 can be significantly suppressed. Incidentally, the nuclear clinker is not limited to the calciner exhaust gas duct 12, but can also be introduced at a position where it flows through all or part of the preheating section 1 like the cement raw material powder, and the temperature of the exhaust gas to be heat exchanged is A convenient location is selected as appropriate.

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 fluidized exhaust gas from the calcination furnace to form a spouted bed 14 (see Fig. 4), and is formed in a body 3A continuous to the above-mentioned calcination furnace 2 and below it. It consists of an inverted conical part 3B.

At the bottom of the inverted conical part 3B, preheated core clinker and calcined cement raw material powder are charged so as to form a hot spot 15 (see Fig. 4) where the material to be granulated is in a semi-molten state. An inlet 16 for the material to be granulated is opened, and an appropriate number of burners 17 are installed near the inlet 16 to heat the material to be granulated.
However, it is installed with a slight upward slope. Inverted conical part 3
An exhaust gas inlet 19 is opened at the lower end of B for introducing the fluidized exhaust gas 18 of the firing furnace which serves as combustion air for the burner 17 and forms the spouted bed 14 described above. Note that the granulated material, in which particles have grown by moving through the spouted bed 14 and the granulated material layer 20, is placed on the side of the inverted conical section 3B or the body section 3A above the granulated material inlet 16. , firing furnace 4
A granulated material discharge port 21 for discharging the granulated material is opened.

In addition, a cooler bleed air introduction port 22 for introducing cooler bleed air is provided above the granulated material inlet 16, and the granulated material layer 2
This makes it possible to activate the movement of zero and also to prevent cooling near the wall surface and adhesion to the wall surface.

The firing furnace 4 is a fluidized bed furnace that is divided into a firing chamber 4A, a ripening chamber 4B, and an annealing chamber 4C, and fires the granulated material in a fluidized bed.
The fluidized exhaust gas of the cooler that has passed through the cooler 5 to cool the clinker is passed through the fluidizing gas inlet 23, 24,
The gas is divided into a portion supplied to the firing chamber 4A and the ripening chamber 4B, and a portion supplied to the slow cooling chamber 4C, and are introduced as fluidizing gas in the firing furnace 4. In addition, although the illustration consists of one firing chamber, one ripening chamber, and one slow cooling chamber, each chamber may be composed of a plurality of chambers.

In such a firing furnace 4, a granulated material discharge port 21 of a granulating furnace 3 is provided.
A granule chute 25 is provided to supply the granules discharged from the annealing chamber 4A to the firing chamber 4A. A throat 26 is connected to introduce slowly cooled exhaust gas having a high oxygen content among the oxidized exhaust gases. On the other hand, in the firing chamber 4A or the aging chamber 4B, a riser pipe 2 is provided which sends high-temperature firing furnace exhaust gas out of the firing furnace fluidized exhaust gas to the exhaust gas inlet 8 of the calcining furnace 2.
7 is connected. In this riser pipe 27, the preheated raw material powder introduced from the cyclone C2 of the preheating section 1 is calcined to some extent. In addition, if a mixing chamber 28 as shown in FIG. 4 is formed in the middle, the heat exchange performance in the riser pipe 27 is further improved, and there is an advantage that the calciner 2 can be made smaller. .

The diameter of the fired clinker is about 1 to 2 mm, and in order to cool it, a fluidized bed similar to that of the firing furnace 4 is used for the cooler 5. This cooler 5 has a high temperature section 5A and a low temperature section 5B.
The cooling air is supplied and discharged to each section independently, and each section is multi-chambered.

In this example, the fluidized exhaust gas in the high temperature section 5A is supplied to the above-mentioned cooler bleed air inlet 22, and the fluidized exhaust gas in the low temperature section 5B is used for fluidization in the firing furnace 4 after being removed by the dust collector 29. The gas is supplied to gas inlets 23 and 24.

The clinker discharged from the cooler 5 is carried out to the next process, and a part of it is used as nuclear clinker. Therefore, a clinker crusher 30 and a screen 31 are installed, and the nuclear clinker input port 13 is transported by a transporter (not shown).
The nuclear clinker will be transported to the United States to ensure that the supply of nuclear clinker will not be interrupted.

According to such embodiments, as will be explained below, the raw material powder can be granulated to a constant particle size, and the desired calcination can be performed to produce high quality clinker.

The cement raw material powder input from the raw material input lower 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 when it is input into the duct 1b, it is suspended in the exhaust gas rising again. Heat exchanged. Such an operation is repeated, and the raw material powder is sequentially transferred to cyclones C3 and C3.
2. The product is calcined to a predetermined temperature while passing from the riser pipe 27 and the calcining furnace 2 to the cyclone CI. In addition, the exhaust gas is sent to the calciner 2.
However, it is discharged from the cyclone C4 following the opposite route to that of the raw material powder. In the calcining furnace 2, 1200-1300 tons of granulation furnace waste 32 from the granulation furnace 3 is accelerated in the constriction part 9 and further heated by the burner 10, and the hot gas is further mixed with 1200 to 1300 tons of granulation furnace waste 32 from the calcination chamber 4A etc.
Approximately 350 tons of fluidized exhaust gas 18 from the firing furnace is passed through the variable throttle 33
The air volume is adjusted by and supplied from the exhaust gas inlet 8,
The air volume is increased. As a result, the cement raw material powder fed into the riser pipe 27 from the cyclone C2 is decarburized. In addition, if a mixing chamber 28 is provided in the riser pipe 27, heat is exchanged between the rising fluidized flue gas of the calcination furnace and the preheated raw material powder charged therein, thereby promoting calcination in the calcination furnace 2. can do.

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 grinder 30. screen 3
1, the grain size is adjusted to less than 1 mm, and the nuclear clinker is introduced through the nuclear clinker inlet 13 provided in the calciner exhaust gas duct 12. This nuclear clinker exchanges heat while floating in the exhaust gas flowing through the duct 12, and is collected by the cyclone CT. The thus preheated nuclear clinker and calcined raw material powder are introduced into a hot spot 15 at a temperature of 1250 to 1350°C from a granulation material inlet 16 opened at the bottom of the granulation furnace 3.
will be put into the

This part contains the fluidized exhaust gas 18 from the kiln furnace from the slow cooling chamber 4C.
is supplied, and the fuel ejected from the burner 17 is combusted. As a result, the material to be granulated is rapidly heated and becomes a semi-molten state, and a spouted bed 14 is formed by the energy of the combustion gas and the fluidized exhaust gas of the kiln, and the core clinker circulates. During this time, the raw material powder adheres and the core clinker, which was less than 1 mm in diameter, grows into a granulated product with a diameter of 1 to 2 mm. In such granulation, by adjusting the burn-up of the burner 17, etc., operating conditions suitable for granulation can be obtained.

Note that the fluidized exhaust gas supplied to the firing furnace may be from the firing chamber 4A or the ripening chamber 4B, but if it is supplied from the slow cooling chamber 4C as shown in the figure, the gas temperature will be slightly lower than 1000 tons. It has the advantage that its oxygen content is high, although only to a certain extent, and combustion by the burner 17 is sufficiently carried out. Fluidized exhaust gas of about 800° C. from the high temperature section 5A of the cooler 5 is supplied to the granule layer 20 from the cooler bleed port 22, activating the granule layer 20 and cooling the wall surface of the inverted conical section 3B. Moreover, it is possible to prevent molten nuclear clinker, raw material powder, or granules from adhering to the wall surface.

The cement raw material that has grown to a predetermined size is supplied from the granule discharge port 21 to the calcination furnace 4 through the granule chute 25 . Fuel is supplied from the fuel supply device 34 and mixed with the granules. The fluidized exhaust gas whose temperature has been raised by passing through the cooler 5 is removed by a dust collector 29, and then supplied as a fluidizing gas to the firing furnace 4 from the fluidizing gas inlet 23,24. The temperature inside the firing furnace 4 is 1350-1450"
c to produce clinker. 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 is transferred to the firing chamber 4A by the granules that are successively introduced from the granule chute 25.
It overflows and moves over the partition wall 35 to the ripening chamber 4B.

The clinker aged in the same manner is transferred to the slow cooling chamber 4C and gradually cooled. In this way, firing, aging,
If slow cooling is performed, 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 overflowing from the slow cooling chamber 4C of the kiln 4 is cooled down to a predetermined temperature by moving through several fluidized beds in the cooler 5, and the clinker is transported to the next final grinding process, etc. be done.

Incidentally, the diameter of the granules hardly changes during firing and cooling, and as mentioned above, the diameter is up to 2 mm, which is smaller than normal clinker, which is convenient because the original size for crushing is reduced.

Incidentally, the granulated material discharged from the granulation furnace 3 may contain small grains 1 and raw material powder.

However, the fine particles that have reached the firing furnace 4 fly out of the fluidized bed in each chamber and are carried along with the firing furnace fluidized exhaust gas into the riser pipe 2.
7, is returned to the granulation furnace 3 via the calcining furnace 2 and the cyclone C1.

Note that since the temperature of the gas flowing through the calciner exhaust gas duct 12 is high, molten raw material powder often adheres to the wall surface of the duct 1-12. Moreover, in this example, since the nuclear clinker is delivered from this duct, welding of the nuclear clinker also occurs. In such a case, the cyclone C of the preheating section 1
If a part of the preheated raw material powder in the preheated raw material powder 2 is supplied from a raw material powder supply port (not shown), the exhaust gas temperature is lowered by the lower temperature raw material powder, and the degree of welding is reduced. Moreover, the preheating of the nuclear tarinka can be maintained at about 1200° C., just before melting. Note that if similar cooling and prevention of welding are required in the granule chute 25 described above, the raw material powder may be supplied from the cyclone CI or C2.

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 granulating it, granulation performance can be improved.

〔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 is easy to set and adjust the operating conditions, and it is possible to achieve granulation with uniform particle size and complete firing at the optimum temperature. Further, since the preheated raw material powder is calcined in the calcining furnace, the firing capacity of the calcining furnace can be reduced.

Furthermore, since nuclear clinker is used, granulation properties are improved (the nuclear clinker is preheated using calciner exhaust gas and then subjected to granulation, so granulation is carried out smoothly and the heat required for that purpose is It is possible to reduce labor and energy consumption.

[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 line nn in FIG. 1, and FIG. 3 is a sectional view taken along line mm in FIG. 1. FIG. 4 is a sectional view of essential parts including an example in which a mixing chamber is provided in the riser pipe. 2-Calcination furnace, 3-Pelletization furnace, 4-.-Calcination furnace, 4A-Calcination chamber, 4B-Aging chamber, 4cm slow cooling chamber, 8-Exhaust gas inlet, 12-Calciner exhaust gas duct I. , 13-nuclear clinker inlet, 14-spouted bed, 16-to-granulated material inlet, 17-
Burner, 18-Calcination furnace fluidized exhaust gas, 19-Exhaust gas inlet, 21-Granule outlet, 22-Cooler bleed air inlet, 2
3.24 - Gas inlet for fluidization, 25 - Granule chute, 27 - Two vertical pipes, 2nd - Vexing chamber, 32
ii Grain furnace exhaust gas.

Claims (10)

[Claims] (1) In a method of producing cement clinker by granulating and firing preheated cement raw material powder, the preheated core clinker is heated to a high temperature semi-molten state, and the fluidized exhaust gas of the kiln is injected into it. The cement raw material powder is supplied to form a spouted bed, and the preheated cement raw material powder is calcined using granulation furnace exhaust gas, and then supplied to the high temperature semi-melting section, and the cement raw material powder is attached to the core clinker to produce cement raw material. A method for firing cement clinker, which comprises granulating the cement, collecting the granules, firing them in a fluidized bed, and then slowly cooling the fired product. (2) 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; The granulation furnace and the calcination furnace for calcining the preheated cement raw material powder are integrally formed on the top and bottom, and the granulation furnace is a spouted bed furnace, and the lower part thereof is the preheated nuclear clinker and the calcination furnace. A granulation material inlet into which cement raw material powder is introduced is opened, a burner is installed near the inlet to heat the granulation material, and an exhaust gas inlet is provided at the lower end to introduce the fluidized exhaust gas from the kiln. A granulated material discharge port for discharging the granulated material above the granulated material input port is opened, and the firing furnace is divided into at least a firing chamber and a slow cooling chamber, and the granulated material is discharged in a fluidized bed. The fluidized bed furnace for firing is provided with a granule chute that supplies the granules discharged from the granule outlet to the firing chamber, and the fluidized exhaust gas of the calcination furnace is supplied to the exhaust gas inlet of the calcination furnace. A cement clinker firing device characterized in that a riser pipe for sending out is connected. (3) The cement clinker according to claim 2, wherein the calciner exhaust gas duct of the calciner is provided with a nuclear clinker inlet for preheating the nuclear clinker. Baking equipment. (4) The cement clinker firing apparatus according to claim 2, wherein the exhaust gas inlet opened to the granulation furnace is connected to an annealing chamber formed in the firing furnace. . (5) Calcining of cement clinker according to claim 4, wherein the slow cooling chamber of the firing furnace has a fluidizing gas inlet for introducing fluidizing exhaust gas of a cooler for cooling the granules. Device. (6) The cement clinker firing apparatus according to claim 2, wherein the riser pipe is connected to a firing chamber or a ripening chamber formed in the firing furnace. (7) The cement clinker sintering apparatus according to claim 6, wherein the sintering chamber of the sintering furnace has a fluidized gas inlet for introducing fluidized exhaust gas from a cooler for cooling the granules. . (8) A mixing chamber is formed in the middle of the riser pipe, as claimed in claim 2.
The cement clinker firing apparatus described in Section 1. (9) The cement clinker firing apparatus according to claim 2, wherein the exhaust gas inlet of the calciner is opened substantially tangentially to the calciner. (10) Cement clinker firing according to claim 2, wherein the granulation furnace has a cooler bleed air inlet for introducing cooler bleed air above the granulation material inlet. Device.