JPS5895632A - Cement raw material coalcining furnace - 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 calcination furnace for cement raw materials, and in particular to a calcination furnace for cement raw materials suitable for combustion of fuels having a low combustion rate such as solid fuels.

In the conventional cement raw material calcining furnace of a rotary kiln with a suspension preheater, as shown in Fig. 1,
Fuel combustion and decarboxylation reactions were carried out simultaneously in the calciner. That is, the raw material a from the suspension preheater enters the combustion chamber bK, and in this chamber, the rotary kiln exhaust gas C and the gas produced by burning the fuel supplied from the fuel burner by the cooler bleed air d are combined, and the entire combustion chamber is In this process, fuel combustion and decarboxylation reactions occur while forming a spouted bed. (In the figure, solid arrows indicate the flow of hot air, and dashed arrows indicate the flow of raw material powder.) At the top of the combustion chamber, there is a space that expands through the diaphragm molecules! is formed, combustion of unburned fuel and calcining of the cement raw material are completed in the space, and the calcined raw material is discharged from the discharge port.

According to this conventional method, the combustion heat of the fuel is immediately used for the calcination reaction of the raw materials, and the temperature inside the furnace is partially K 1000.
The average temperature in the furnace was 1900°C, which was relatively low, and the burning rate of fuel in the furnace was also relatively low.

In this way, conventional methods do not have anything that acts as a spark, so when using pulverized coal with a slow combustion rate, especially coke with a low volatile content,
Combustion efficiency was drastically reduced.

The present invention addresses this drawback and provides a cement raw material calciner that can maintain good combustion efficiency even when using various fuels such as pulverized coal with a slow combustion rate. In a rotary kiln equipped with a suspension preheater equipped with a cement raw material calciner, the cement raw material calciner is composed of a hot air generating furnace and a jet decarboxylation reaction chamber connected above the hot air generating furnace. A kiln exhaust gas inlet is provided at the bottom of the furnace, a frame holder is provided on the side wall to receive cooler bleed air, and a fuel supply pipe is provided in the frame holder. be.

The present invention will be described below with reference to illustrated embodiments.

Figure 2 shows an overall view of a rotary kiln equipped with a cement raw material calcining furnace and a nine-suspension preheater.
Fi rotary kiln 2 is a cement raw material calcining furnace, and the figure illustrates the method of the present invention. The 8tj cooler 4 is equipped with a 4-tube, 5#i suspension preheater for guiding cooler bleed air to the cement raw material calcining furnace 2, and cyclones 51 to 54t. 6 is a preheater raw material feeder, and 7 is a ninth chute for supplying raw materials from the suspension preheater 6 to the cement raw material calciner 2.

In Ii1, the raw material supplied to the preheater from the preheater raw material feeder 6Flc passes through the chute 7 preheated in the suspension preheater 5 and enters the calciner 2.

For example, as shown in FIG. 8, the calcining furnace 2 is composed of a hot air generating furnace 10, a two-stage jet decarboxylation reaction chamber 11, a two-stage jet decarboxylation reaction chamber 11ti, a lower jet chamber 111, and an upper jet chamber 11.
．． It consists of.

The hot air generating furnace 10 is formed from a frame holder part 1o1 and a cylindrical part 1. The frame boulder part 10° is a short cylindrical part, and the cylindrical part 10. It is formed in multiple places on the side wall of.

First, the fuel e is combusted from the cooler bleed air dK in the frame holder part 1, thereby generating combustion heat and forming the burner 7 frame. The ignition mass of this burner frame is 1800° C. or higher, and furthermore, a central portion j of the hot air generating furnace 10 (a local high temperature region j of 1200° C. or higher) is formed.

Generally, as the combustion temperature increases, the combustion rate increases exponentially. Because of this localized high-temperature region, the combustion rate of the fuel is extremely high, and flame-retardant fuels that cannot be burned sufficiently in conventional calciners, such as coal with a volatile content of 10 or less, and It can also be easily combusted with coke, low-rank coal, and natural gas.

On the other hand, 1 part m (0-40%) of the raw material & preheated by the suspension preheater 5 is introduced into the inner wall of the hot air generating furnace 10 to protect the furnace wall. Hot air generator 1
The amount of raw material introduced into the fuel tank varies depending on the burning rate of the fuel.For solid fuels with a volatile content of 5 seconds or less, the amount of raw materials introduced into the fuel tank is almost zero.

The high-temperature combustion gas generated in the hot air generating section 10 is introduced into the two-stage jet decarboxylation reaction chamber 11 through the constriction section 12 . The two-stage jet decarboxylation reaction chamber consists of upper and lower two-stage jet chambers, and forms upper and lower spouted layers with the constricted portion 13 as a boundary.

The raw material preheated by the preheater 5 ~6096 is introduced into the lower jet chamber 1111/c of the two-stage jet decarboxylation reaction chamber, and the decarboxylation reaction is carried out indoors. Further, the unburned phosphorus from the hot air generating furnace 10 is sufficiently reburned in the reaction chamber 11 due to the mixing effect caused by the contraction and expansion of the throttle portion 12.13.

Thus, in the embodiment shown in FIG.
is formed, and cement raw materials can be efficiently calcined using solid fuel with low volatile content or natural gas with low combustion rate.

Note that the cylindrical portion 10 of the hot air generating furnace IO. The cross section of may be the same as the cross section of the two-stage jet decarboxylation reaction chamber 11, or may be larger.

In addition, in order to provide the calcination furnace of the present invention with a nitrogen oxide reduction function, the air for re-combustion is supplied to the two-stage jet decarboxylation reaction chambers ii, i.
i, or the inlet duct 8 of the separation cyclone 54, or a part of the separation cyclone 54 can be introduced in a branched manner.

Although the above explanation has been about the embodiment of the present invention based on the conventional device shown in FIG. 1, it goes without saying that the present invention can be modified in various ways within the scope of its gist.

For example, as shown in FIG. 4, the constriction section 13 can be removed from the decarboxylation reaction chamber 11. The symbols of each part in FIG. 4 correspond to those in FIG. 8.

In the calcining furnace of the present invention, the hot air generating furnace is provided with a flame holder, so that when the core becomes red hot and a local high temperature area is formed, the radiant heat can be effectively used for ignition of the T-flame. Sexual fuel can also be burned sufficiently.

[Brief explanation of the drawing]

Figure 1 is a conceptual diagram of a conventional cement raw material calciner, Figure 2 is an overall conceptual diagram of a rotary kiln with a suspension preheater incorporating the cement raw material calciner of the present invention, and Figure 8 is a conceptual diagram of a cement raw material calciner according to the present invention. FIG. 4 is a conceptual diagram of another embodiment of the cement raw material calcining furnace of the present invention.・ 1O・・・Hot air generating furnace, 10.・・・・・・
Frame holder part, 1...Cylindrical part, 11
...Two-stage jet decarboxylation reaction chamber, 111...
・Lower jet chamber, 11. ......Upper jet chamber, 12
, 13... Aperture section.

Claims (1)

[Scope of Claims] 1. A rotary kiln equipped with a cement raw material calcining furnace and a nine-suspension preheater, in which the cement raw material calcining furnace is composed of a hot air generating furnace and a jet decarboxylation reaction chamber connected thereabove, The generating furnace has an inverted cone-shaped lower part, a kiln exhaust gas inlet is provided at the bottom, a frame holder is provided on the side wall to receive cooler bleed air, and a fuel supply pipe is provided in the frame holder. Cement raw material calcining furnace. 2 The hot air generating furnace has a cylindrical part, and the Fli of the cylindrical part
A cement raw material calcining furnace according to claim 1, further comprising a chute for supplying raw material from a suspension preheater to a suspension preheater. 3. The jet decarboxylation reaction chamber is connected to the constriction section at the top of the hot air generating furnace, and the reaction chamber is composed of two or more stages of jet decarboxylation reaction chambers, and the jet decarboxylation reaction chamber is arranged in a lower jet chamber. The cement raw material calcining furnace according to claim 1, further comprising a shade for supplying the raw material from the suspension preheater, and a duct connected to the cyclone on the upper side of the upper jet chamber. 4. The cement raw material calcining furnace according to claim 8, wherein a constriction part is provided between the lower jet chamber and the upper jet chamber.