JPS59102848A - Cement raw material baking equipments - 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 The present invention relates to a cement raw material firing device, and more particularly, to a cement raw material firing device that uses a part of the exhaust gas discharged from the device for drying the cement raw material, and makes effective use of all the heat contained in the remaining exhaust gas. The present invention relates to a raw material firing device.

Modern cement production consists of a so-called suspension-type raw material preheating device, which has multiple stages of stacked cyclones and a calciner placed below, a rotary kiln, and a product cooler, and supplies fuel to the calciner and rotary kiln. The mainstream is the dry method in which cement is fired by burning it.

The exhaust gas discharged from the uppermost cyclone of the suspension type raw material preheating device (hereinafter referred to as SP exhaust gas) has a temperature of approximately 350°C and a gas amount of approximately 1.4 Nm'' per 1 kg of cement clinker.SP exhaust gas I Approximately 1002 cement raw material dusts are included in Nm''.

Conventionally, as shown in Fig. 1, a part of the SP exhaust gas A is led to a cement raw material dryer 1 and a cement raw material mill 2 to be used for drying the cement raw material, and the excess SP exhaust gas is passed through a conduit 3. Together with the outlet gases of the dryer 1 and mill 2, it is led to a dust remover 4 to remove cement raw material dust and then disposed of through a chimney 5.

The amount of SP exhaust gas introduced into the raw material dryer 1 and raw material mill 2 varies depending on the moisture content of the cement raw material, but in normal cases,
It is about 50 to 60 inches of the total amount of SP exhaust gas, and it is difficult to say that the amount of heat held by SP exhaust gas is fully utilized. Although this SP exhaust gas has a large amount of heat, as mentioned above, The temperature is relatively low at about 350 degrees Celsius, and the deer can also reach 100 degrees Fahrenheit.
However, the cement industry is rapidly switching from petroleum to coal as a fuel, and recently, high-quality coal with a high calorific value is being used. There is an increasing need to dry lignite, etc., which contains a lot of moisture, and use it as fuel.
This was done to effectively utilize the heat of P exhaust gas.
A rotary furnace that uses coal as its entire fuel, a multi-stage preheater group that uses exhaust gas from the rotary furnace as heating gas, and a conduit that leads the exhaust gas from the preheater group to a fluidized bed coal dryer that connects to a coal supply device. The present invention relates to an apparatus for firing cement raw materials, characterized in that the apparatus has a dust collector installed in the middle of the conduit.

That is, in the device of the present invention, surplus SP exhaust gas is introduced into a dust removal device such as an electrostatic precipitator to remove cement raw material dust accompanying the SP exhaust gas, and then the SP exhaust gas is used as fuel for the calcination equipment. After heat exchange with coal using a fluidized bed device to completely reduce the water content in the coal, the coarse dry coal is crushed to an appropriate particle size in a crusher and used as fuel for a rotary kiln or a rotary kiln and a calciner. The fine-grained coal is used as fuel for the total calciner, which is entrained in the exhaust gas at the outlet of the fluidized bed device.

FIG. 2 is a diagram showing an outline of an embodiment of the apparatus of the present invention.

In Figure 2, 1 is a raw material dryer, 2 is a raw material mill, and 3 is s
a dust collector installed in the sp exhaust gas inlet pipe of the fluidized bed device 6 that dries the coal by exchanging total heat with the p flue gas and coal;
4 is a dust collector, 5 is a chimney, 6Fi fluidized bed device, 7 is a dust collector installed at the outlet of the fluidized bed device B, 8 is a dry coal pulverizer, 9 is a rotary kiln burner, 10 is a temporary Furnace burner, 11Fi coal-fired rotary kiln,
12 is a calcining furnace; 13 is a raw material preheating device made by stacking a plurality of cyclones; the device is used for heating the exhaust gas from the rotary kiln 11; 14 is a blower; 15 is a product cooler; 16 is a coal supply device. It is.

In FIG. 2, SP discharged from the raw material preheating device 13
The exhaust gas is used in the cement raw material dryer 1 and the cement raw material mill 2, and the excess SP exhaust gas is introduced into a dust removal device 3 such as an electrostatic precipitator to be purified, and then introduced into the fluidized bed device B, where it is fed into the coal supply device 16. The coal from the coal supplied to the fluidized bed apparatus 6 is exchanged with coal. As a result, the moisture content of the coal is reduced and the calorific value is increased.

Coarse dry coal taken out from the fluidized bed device 6 is sent to a crusher 8
After being pulverized, it is used as a fuel for the rotary kiln 11 or the rotary kiln 11 and the calciner 12.

On the other hand, fine coal particles entrained in the exhaust gas exiting the fluidized bed apparatus 6 are collected by a dust collector 7 and used as fuel for the calciner 12.

It goes without saying that the cement raw material dried in the raw material dryer 1 and crushed in the raw material mill 2 is introduced into the raw material preheating device 13 through a pipe (not shown) and subjected to a normal firing process.

The effects of the above device of the present invention are as follows.

(1) The temperature of the SP exhaust gas discharged from the raw material preheating device 13 (approximately 350°C) is a temperature suitable for drying coal, and the heat of surplus SP exhaust gas that was previously discarded can be effectively used. This saves fuel for drying coal.

(2) Since the cement raw material dust entrained in sp exhaust gas is an uncalcined raw material,
If this cement raw material dust is contained in the dry coal burned in burner 9, the combustion flame temperature will decrease, and it will be mixed into the product in rotary kiln 11, reducing product purity. Rotary kiln 11 The coating does not easily adhere to the inner wall of rotary kiln 1.
This impedes the stable operation of step 1.

However, in the present invention, the cement raw material dust t4 accompanying the SP exhaust gas is removed in advance by the dust collector 3, and then introduced into the fluidized bed equipment B for heat exchange with coal, and in the fluidized bed equipment 6, the Because the heat exchangeability between the SP exhaust gas and the coal is excellent, and at the same time the solid particle classification effect is good, the cement raw material dust that remains after passing through the dust collector 3 is absorbed into the coal introduced into the crusher 8. The above problem can be avoided by hardly mixing.

(3) In the cased calcining furnace 12, the fuel is burned in the presence of concentrated cement raw material to completely calcine the cement raw material, so as in the present invention, the dust is collected by the dust collector 7. There is no problem even if fine-grained coal containing some cement raw material dust is supplied to the burner 10, and the yield of cement raw material is improved.

Table 1 shows calculation examples of heat utilization of sp exhaust gas according to the present invention under the following conditions.

<Conditions> SP exhaust gas: Temperature: 350°C Flow rate: 1.3 N-shikori/Talinka coal: Raw coal moisture 22nd dry coal moisture 5% Combustion amount [1215~・Dried coal/Kq・Clinker calorific value 3850 Meal/Pg Table 1 Example of heat utilization of 8P exhaust gas

[Brief explanation of drawings]

FIG. 1 is a flow diagram of a conventional SP exhaust gas, and FIG. 2 is a schematic diagram showing an embodiment of the apparatus of the present invention.

Claims (1)

[Claims] A rotary furnace that uses coal as fuel, a multi-stage preheater group that uses exhaust gas from the rotary furnace as heating gas, and a conduit that leads the exhaust gas from the preheater group to a fluidized bed coal dryer that connects to a coal supply device. 1. An apparatus for firing cement raw materials, characterized in that a dust collector is installed in the middle of the conduit.