JP3016567B2 - Method for producing spherical cement and apparatus for producing spherical cement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial application field" The present invention relates to a method for producing a spherical cement which makes it possible to produce a dense concrete by reducing the water-cement ratio and to carry out this production method. It relates to a suitable manufacturing apparatus.

`` Prior art '' Conventionally, for example, to manufacture Portland cement as cement, the raw material is crushed and supplied to a suspension preheater, preheated, and further baked in a rotary kiln, and then the cement clinker obtained in a cooler is used. Quench with air. Then, gypsum powder is added to the cooled cement clinker, which is further pulverized again by a tube mill or the like to obtain a cement having a desired particle size.

"Problems to be Solved by the Invention" By the way, in the cement obtained in this manner, since the cement has a square shape due to pulverization, the frictional resistance between the particles is large and the cement and water are kneaded. ,
There is a problem that the fluidity and the filling property are slightly inferior.

In addition, in order to solve such a problem, the present inventors,
First, a method for producing a spherical cement in which a cement clinker pulverized material is passed through a high-temperature flame to be in a molten or semi-molten state, and then cooled, and thereafter gypsum powder is added, has been proposed. However, although this method can provide cement which is spherical and therefore excellent in fluidity and filling properties, energy consumption is required because spheroidizing treatment is performed by passing ground cement clinker into a high-temperature flame from a burner. However, there is a new problem that the manufacturing cost increases.

Means for Solving the Problems Therefore, in the method for producing spherical cement according to claim 1 of the present invention, exhaust gas from a cooler of a cement kiln is used as a combustion supporting gas in a burner for generating a high-temperature flame, and The above object has been attained by supplying exhaust gas from the burner for generating a high-temperature flame into a pre-heater or a rotary kiln of a cement kiln.

Further, the apparatus for producing spherical cement according to claim 2 includes a suspension preheater for preheating the raw material powder, a rotary kiln to which the raw material powder is supplied from the suspension preheater, and a cooler to which the raw material is supplied from the rotary kiln. And a burner for generating a high-temperature flame was provided, an introduction pipe for guiding the exhaust gas from the cooler to the burner was provided, and a supply pipe for supplying the exhaust gas from the burner to a preheater or a rotary kiln of the cement kiln was provided. This is the solution to the above problem.

[Operation] According to the method and the apparatus for manufacturing a spherical cement of the present invention, since the heated exhaust gas from the cooler is used as the combustion supporting gas for the burner, the combustion efficiency in the burner is increased. Further, since the combustion exhaust gas from the burner is supplied to the exhaust gas supply unit of the suspension preheater, the combustion (firing) heat required for spheroidizing the cement clinker is recovered and effectively used, thereby producing cement. The thermal efficiency of the entire device increases.

In addition, the spherical cement obtained based on the production method according to claim 1 has a small frictional resistance between particles due to being spherical, and therefore has a large flow value at the same water cement ratio as compared with the conventional cement. It becomes what has.

"Example" Hereinafter, the present invention will be described in detail with reference to the drawings based on the apparatus for manufacturing a spherical cement according to the second aspect of the present invention.

1 to 3 show one embodiment of the manufacturing apparatus according to the second aspect of the present invention. In these figures, reference numeral 1 denotes a high-temperature flame generator 1. The high-temperature flame generator 1 comprises a burner 2 and a cyclone 4 provided on the crater 3 side of the burner 2 as shown in FIGS. Burner 2 is propane,
Combustible gas such as butane, propylene, acetone and hydrogen; liquid fuel such as heavy oil and light oil or petroleum; and solid fuel such as oil coke as fuel. These fuels and supporting gas such as oxygen or air Is supplied and a high-temperature flame is ejected from the crater 3, and a fuel supply unit 5 and an exhaust gas introduction unit 6 are arranged on the side opposite to the crater 3. The introduction unit 6
As shown in the figure, it is connected to an exhaust wind turbine 9 of a cooler 8 of a cement kiln 7 through an introduction pipe 10.

Here, the cement kiln 7 includes a suspension preheater 11 for preheating the raw material powder, a rotary kiln 12 disposed downstream of the suspension preheater 11,
The SP kiln further includes a cooler 8 disposed downstream of the rotary kiln 12. The raw material powder preheated and calcined by the suspension preheater 11 is fired by the rotary kiln 12, and further quenched by the cooler 8. Is what you do.

That is, in the example shown in FIG.
A blowing windmill 13 is disposed downstream of the rotary winder 13, and hot air is introduced into the rotary kiln 12 from the blowing windmill 13 so that the raw material powder is baked in the kiln 12. The hot air obtained by firing the raw material powder is cooled by contacting the raw material powder, and flows into the suspension preheater 11 in that state,
The raw material powder is preheated in the heater 11. Further, the cooler 8 is provided with a blow-in wind turbine 14 for cooling on the upstream side thereof, so that the cool air blown from the cooler 8 rapidly cools the cement clinker that has been fired in the rotary kiln 12 and then sent. . The cold air that has cooled the cement clinker is heated by contact with the cement clinker, and is discharged from the exhaust windmill 9 disposed downstream of the cooler 8 in that state,
It is guided to the introduction section 6 of the burner 2 through the introduction pipe 10.

In the high-temperature flame generator 1, the cyclone 4 is
As shown in FIG. 2, a cylindrical side wall 4a and a tapered bottom wall 4b
Made of a bottom wall 4b is formed in double, which is assumed to water during this period as indicated by the second arrow in the figure W _1, W ₂ is cooled in a cyclone 4 by circulation. Side wall
Above 4a, a flame tube 15 extending in a tangential direction is provided on a part of the side wall 4a as shown in FIG. The crater 3 of the burner 2 is arranged in the mouth of the flame tube 15 on the side opposite to the cyclone 4.
Causes the flame to be generated in the flame tube 15. In the flame tube 15, an opening 16a of a raw material supply tube 16 is disposed in front of the crater 3 of the burner 2 as shown in FIG. The raw material supply pipe 16 is for supplying a ground cement clinker whose average particle size is adjusted as described later to the front of the crater 3 of the burner 2 so as to pass through the flame from the burner 2.

The cyclone 4 is provided with a lid 17 covering the upper opening at the upper end of the side wall 4a, and a communication pipe 18 for passing the inside and outside of the cyclone 4 is provided at a substantially central portion of the lid 17.
Is mounted through. The communication pipe 18 guides the exhaust gas from the burner 2 to the outside of the cyclone 4, and the end opposite to the cyclone 4 side has the exhaust gas to the suspension preheater 11 as shown in FIG. It is connected to the supply unit 19a or 19b.

In order to produce spherical cement using the high-temperature flame generator 1 and the cement kiln 7 having such a configuration, first, the raw material powder is pulverized and supplied to the suspension pre-heater 11 in the same manner as in the prior art, and preheated. Then, the preheated raw material powder is fired in the rotary kiln 12, and the resulting cement clinker is quenched in the cooler 8 with cool air. Then, the cooled cement clinker is finely pulverized by a tube mill or the like, and classified to obtain a pulverized cement clinker having an average particle diameter of 60 μm or less. Here, the average particle size of the pulverized cement clinker is set to 60 μm or less because the average particle size of the finally obtained spherical cement is 40 μm.
The reason why the average particle diameter of the spherical cement is about 40 μm or less is to sufficiently improve its fluidity and filling property. The reason why the average particle diameter of the pulverized cement clinker is larger than that of ordinary cement particles is that the apparent average particle diameter becomes smaller by spheroidization as described later.

Next, fuel is supplied to the burner 2 from the fuel supply unit 5, and the introduction pipe 10 is supplied from the cooler 8 of the cement kiln 7.
Then, the heated exhaust gas (air) from the cooler 8 is supplied to the burner 2 through the introduction section 6, and the burner 2 is further ignited to generate a high-temperature flame.

Next, the cement clinker pulverized matter whose particle size has been adjusted is once stored in a tank (not shown), and the raw material supply pipe 16 is further supplied from this tank.
A predetermined amount of the cement clinker pulverized material is supplied into the high temperature flame from the burner 2 in the flame tube 15 in the flame tube 15 and is melted or semi-melted.

Then, the melted or semi-molten cement clinker pulverized material is blown out by the flame with the flame and guided into the cyclone 4, where it is cooled and spheroidized by its surface tension. Then, the cooled and spheroidized cement clinker pulverized material (hereinafter referred to as a spherical cement clinker particle) falls downward while rotating along the side wall 4a and the bottom wall 4b in the cyclone 4, and further cools down from the bottom wall 4b. And is sufficiently cooled, and then discharged from the outlet 20 of the bottom wall 4b.

On the other hand, the fuel exhaust gas from the fuel and the combustion supporting gas (exhaust gas from the cooler 8) is guided to the cyclone 4, and then separates from the spherical cement clinker particles due to the high temperature and rises to communicate. The gas is guided to the pipe 18 to the exhaust gas supply unit 19a or 19b, and further supplied to the suspension preheater 10.

The flame temperature from the burner 2 depends on the type of cement, but it needs to be at least 1300 ° C or higher, preferably 1500 ° C or higher. If it is lower than 1300 ° C, the pulverized cement clinker is in a sufficiently molten or semi-molten state. Therefore, the pulverized cement clinker is not sufficiently spherical, which is not preferable. The residence time in the flame is preferably about 0.01 to 0.02 seconds. Further, when a fuel containing a large amount of ash is used as the fuel of the flame generator, it is necessary to adjust the blending of the cement raw material in advance so that the cement component becomes a target component.

Thereafter, an appropriate amount of gypsum powder is added to the obtained spherical cement clinker particles, and a desired hydraulic speed is adjusted to obtain a spherical cement. Here, the average particle size of the gypsum powder is preferably about 80 μm or less in order to enhance the fluidity and filling property of the obtained cement.

In the cement manufacturing apparatus having the high-temperature flame generator 1 and the cement kiln 7 having such a configuration, the burner 2 uses the heated exhaust gas from the cooler 8 as the combustion supporting gas for the burner 2. And the combustion efficiency at the furnace can be increased to obtain a higher temperature flame. Also,
Since the combustion exhaust gas from the burner 2 is supplied to the exhaust gas supply units 19a and 19b of the suspension preheater 10, the combustion (firing) heat required for spheroidizing the cement clinker is recovered and used effectively. Thus, the thermal efficiency of the entire cement manufacturing apparatus can be improved.

In addition, the spherical cement obtained by such a cement manufacturing apparatus has a small frictional resistance between particles due to its spherical shape, and thus has a large flow value at the same water cement ratio as compared with conventional cement. Becomes
Since the fluidity and the filling property are improved by this, the strength of the hardened cement after hardening is higher than that of the conventional cement.

FIG. 4 is a view showing another embodiment of the manufacturing apparatus according to claim 2 of the present invention. The difference between the manufacturing apparatus shown in this figure and the manufacturing apparatus shown in FIG. 1 is the position of the supply section of the combustion exhaust gas from the burner 2.

The cement kiln 21 shown in FIG. 4 includes a suspension preheater 22 for preheating the raw material powder, a rotary kiln 23 disposed downstream of the suspension preheater 22, and a cooler disposed downstream of the rotary kiln 23. 24, an NSP kiln comprising a suspension preheater 22, a calciner 25, and a return pipe 27 for returning heated air from the cooler 24 to the calciner 26. . In this example, the supply portion 19c of the combustion exhaust gas from the burner 2 is provided in the calciner 25 of the suspension preheater 22, 19d and 19e are provided in the suspension preheater 22, and 19f is provided downstream of the rotary kiln 23. The continuous pipe 18 of the cyclone 4 is connected to one or more of these supply units 19c, 19d, 19e, 19f.

In such a manufacturing apparatus, since the exhaust gas from the cooler 24 is used as the combustion supporting gas of the burner 2, the combustion efficiency in the burner 2 is increased, of course.
Since the combustion exhaust gas from the burner 2 is supplied to the exhaust gas supply units 19c, 19d, 19e and 19f of the suspension preheater 22, the combustion (firing) heat required for spheroidizing the cement clinker is recovered and the cement is cooled. The thermal efficiency of the entire manufacturing apparatus can be improved.

[Effect of the Invention] As described above, the method for producing a spherical cement according to claim 1 of the present invention uses heated exhaust gas from a cooler as a combustion supporting gas for a burner. The combustion efficiency in the burner is increased, so that a higher temperature flame can be obtained. Therefore, the heat energy cost required for the spheroidizing treatment of the pulverized cement clinker can be reduced. In addition, since the combustion exhaust gas from the burner is supplied to the exhaust gas supply section of the suspension preheater, the combustion (firing) heat required for the spheroidization of the pulverized cement clinker is recovered and used effectively for cement production. The thermal efficiency of the whole apparatus can be increased, and therefore, the production cost of cement can be reduced.

In addition, the spherical cement obtained by such a cement manufacturing method has a small frictional resistance between particles due to its spherical shape, and therefore has a large flow value at the same water cement ratio as compared with conventional cement. Becomes
Since the fluidity and the filling property are improved by this, the strength of the hardened cement after hardening is higher than that of the conventional cement.

The apparatus for producing spherical cement according to claim 2 is an apparatus suitable for carrying out the above-mentioned production method. Therefore, the thermal energy cost required for the spheroidizing treatment of the pulverized cement clinker is reduced, and the production cost of cement is reduced. The same effect as that of the manufacturing method according to claim 1 can be obtained, for example, it can be reduced.

[Brief description of the drawings]

FIG. 1 to FIG. 3 are diagrams showing an embodiment of the apparatus for producing spherical cement according to claim 2 of the present invention,
FIG. 1 is a schematic configuration diagram of a manufacturing apparatus, FIG. 2 is a side sectional view showing a schematic configuration of a high-temperature flame generator, FIG. 3 is a cross-sectional view of the same high-temperature flame generator, and FIG. It is a figure which shows the other Example of an apparatus, and is a schematic block diagram of a manufacturing apparatus. 1 High-temperature flame generator, 2 Burner, 6 Introductory part, 7,21 Cement kiln, 8,24 Cooler, 11,22 Suspension heater, 12,23 Rotary kiln, 19a , 19b, 19c, 19d, 19e, 19f ... Exhaust gas supply unit.

Continuation of the front page (72) Inventor Akihiko Miyauchi 3-7-9 Tsudanuma, Narashino City, Chiba Prefecture (56) References JP-A-64-72945 (JP, A) JP-A-2-192439 (JP, A) Hei 2-311338 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 7/36 C04B 7/02 C04B 7/48 C04B 7/00

Claims (2)

(57) [Claims] 1. A cement clinker pulverized material is passed through a high temperature flame by a burner to be in a molten or semi-molten state,
Then, this is cooled, and thereafter, when producing globular cement by adding gypsum powder, using exhaust gas from a cooler of a cement kiln as a combustion supporting gas in the burner for generating a high-temperature flame,
A method for producing spherical cement, comprising supplying exhaust gas from a burner for generating a high-temperature flame into a preheater or a rotary kiln of a cement kiln. 2. A cement production apparatus comprising: a suspension preheater for preheating a raw material powder; a rotary kiln to which the raw material powder is supplied from the suspension preheater; and a cooler to which the raw material is supplied from the rotary kiln. A burner that generates a flame is provided, an introduction portion that guides exhaust gas from the cooler to the burner is provided, and a supply portion that supplies exhaust gas from the burner to a preheater or a rotary kiln of a cement kiln is provided. To manufacture spherical cement.