JPS61270242A - Operation control for cement clinker 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] [Field of Industrial Application] The present invention relates to an operation control method in a cement clinker production furnace, and more specifically, an operation control method that detects the occurrence of agglomeration in the inner layer of the furnace and performs an operation to eliminate it. Regarding control method. This is used in the field of technology for manufacturing clinker by granulating and firing cement raw material powder.

[Prior art]

As shown in Fig. 1, cement clinker is manufactured by a granulation furnace 2 that granulates cement raw material powder at high temperature, and a firing furnace 3 that sinteres the granules supplied from the granulation furnace 2 at high temperature. In the apparatus 1, a spouted bed 4A is formed in the granulation furnace 2, and a fluidized bed 4B is formed in the firing furnace 3. In the spouted bed 4A and fluidized bed 4B, if the temperature rises too much during granulation or firing, the melting of the semi-molten cement raw material powder and granules will be further accelerated, and the viscosity of the raw materials will increase. increase As the viscosity increases, raw materials and granules exposed to high temperatures solidify into lumps, a phenomenon known as agglomeration. It becomes attached to. On the other hand, as agglomeration occurs, fluidized air and jet exhaust gas blow through the spouted bed 4A and fluidized bed 4B,
The pressure difference between those layers drops rapidly.

Normally, when agglomeration occurs, a supervisor stops the supply of fuel and air to stop the operation of the device 1.

Then, the above-mentioned deposits inside the furnace are broken up with a rod inserted through the peck holes, etc., to eliminate agglomeration. However, this work is difficult and requires a great deal of effort and time to restart, and there is a problem in that clinker productivity drops significantly due to suspension of operation. On the other hand, if the furnace inner layer is operated at a slightly lower temperature in order to prevent the occurrence of agglomeration, granulation and calcination reactions become inactive, hindering clinker production and reducing its quality. There's a problem.

[Purpose of the invention]

The present invention was made in view of the above-mentioned problems, and its purpose is to maintain the temperature of the inner layer of the furnace as high as possible, to activate the granulation action and calcination reaction, and to prevent agglomeration from occurring. The object of the present invention is to provide a method for controlling the operation of a cement clinker production furnace, which can quickly detect agglomeration and perform a quick action to eliminate agglomeration.

[Structure of the invention]

As shown in FIG. 1, the characteristics of the operation control method for a cement clinker production furnace of the present invention include a granulation furnace 2 that granulates cement raw material powder and the like to produce cement clinker, and a granulation furnace 2 that granulates the granulated product. In a cement manufacturing furnace such as a fluidized bed type firing furnace 3, it is detected that the pressure difference in the furnace inner layer 4 in the manufacturing furnace 20 has become smaller than the set differential pressure value α, and the temperature of the furnace inner layer 4 is increased. It detects that the rate of change has become larger than the set change value C, and outputs a signal to start the elimination operation to eliminate agglomeration in the furnace inner layer 4 based on both of the detection signals. Elimination of agglomeration is detected by recovery of the N4 pressure difference within the furnace, and the agglomeration elimination operation is stopped.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The operation control method of the present invention will be explained in detail below based on an embodiment of a cement clinker manufacturing apparatus in which the method is implemented.

A cement clinker manufacturing apparatus 1 shown in FIG.
The cement clinker production furnace 20 includes a cement clinker manufacturing furnace 20 such as a furnace 3 and a firing furnace 3, and other equipment not shown. The granulation furnace 2 is
This is a furnace for granulating cement raw material powder, and is provided independently from the firing furnace 3 for firing the granulated material in order to facilitate operations for enhancing the granulation effect within the furnace. This granulation furnace 2
This is a spouted bed furnace which introduces firing furnace exhaust gas to form a spouted bed 4A which is the inner layer 4 of the furnace, and is composed of a body portion 2A and an inverted conical portion 2B formed below the body portion 2A.

A raw material powder inlet 5 for inputting cement raw material powder is opened at the lower part of the inverted conical part 2B, and an appropriate number of burners 6 for heating the material to be granulated are installed near the inlet 5. -ru. An exhaust gas inlet 8 is opened at the lower end of the inverted conical portion 2B to introduce the firing furnace exhaust gas 7 which serves as combustion air for the burner 6 and forms the spouted bed 4A. In addition,
Inverted conical part 2B or body part 2 above raw material powder inlet 5
A granule discharge port 9 is opened at the side of A for discharging the granules, in which particles have grown by circulating in the spouted bed 4A, to the firing furnace 3. Further, an exhaust gas outlet pipe 10 is connected to the upper end of the granulation furnace 2 for discharging the exhaust gas that has passed through the granulation furnace 2, and the exhaust gas is led out to a raw material powder preheating section (not shown).

The firing furnace 3 is a fluidized bed furnace that fires the granules in a fluidized bed 4B, which is the furnace inner layer 4. A granulated material chute 11 is provided to supply the granulated material to the fluidized bed 4B, and a firing furnace exhaust gas duct 12 is connected above the furnace to send the firing furnace exhaust gas 7 to the exhaust gas inlet 8 of the granulating furnace 2. Further, an air distribution plate 13 is provided at the bottom of the firing furnace 3, and an air introduction pipe 14 for introducing fluidizing air into a wind box formed at the bottom of the firing furnace 3 is connected to the distribution plate 13. A fuel supply pipe 15 for supplying fuel such as pulverized coal to the fluidized bed 4B is attached, and a transfer pipe 16 for sending fired cement clinker to a cooler (not shown) is provided.

In such a manufacturing apparatus 1, the spouted bed 4A and the fluidized bed 4
A differential pressure detector 17 for detecting the absolute value of the layer pressure difference at B to P is interposed in each detection tube 18A, 18B. Further, the temperature in the spouted bed 4A and the fluidized bed 4B is detected by a temperature sensor 19, for example, at a position close to the furnace wall.

According to such an embodiment, as described below, agglomeration occurring in the cement clinker production furnace 20 is automatically detected, and an operation start signal based on the detection causes the agglomeration elimination operation to be immediately performed. It is done.

First, to briefly explain the manufacturing process of cement clinker,
As shown in the figure, cement raw material powder is introduced into the lower part of the spouted bed 4A from the raw material powder inlet 5 opened at the lower part of the granulation furnace 2. The firing furnace exhaust gas 7 from the firing furnace 3 is supplied to this portion, and the fuel ejected from the burner 6 is combusted. As a result, the material to be granulated is rapidly heated and becomes a semi-molten state, and the energy of the combustion gas and firing furnace exhaust gas forms a spouted bed 4A, and the granulated material circulates and grows to a predetermined thickness. The granules are supplied to the kiln 3 through the granulate outlet 9 . Powdered coal and the like are supplied from a fuel supply pipe 15 connected to a fuel supply device (not shown). The temperature inside the firing furnace 3 is maintained at a high temperature of 1350 to 1450°C, and cement clinker is manufactured. The clinker is delivered to a cooler via a transfer pipe 16.

The detection of agglomeration in the granulation furnace 2 and the firing furnace 3 that occur in the above-mentioned cement clinker manufacturing process and the operation for eliminating the same will be explained based on the graph shown in FIG. 2 and the flowchart shown in FIG. 3. .

When the cement clinker manufacturing apparatus 1 enters steady operation, the differential pressure detector 17 and the temperature sensor 19 are placed in a measurement mode. The differential pressure detector 17 measures the pressure difference ΔP in the furnace inner layer 4 shown in FIG. 1, and compares the value with a set differential pressure value α. The differential pressure △P is usually a value △P as shown in Figure 2.
a, which is almost constant although it fluctuates slightly over time.

Note that the differential pressure value α is considered to be a value with a high possibility of occurrence of agglomeration detection. Therefore, if the detected value is larger than the set differential pressure value α (step 1 of the flowchart,
(hereinafter referred to as Sl), it is ignored. Now time t
It is assumed that the abnormality starts at time 1 and continues until time L2. If the pressure difference P becomes smaller than the set pressure difference value α, there is a possibility that agglomeration has started. Therefore, temperature sensor 1
9, the magnitude of the rate of change in temperature rise detected is determined (S2). If the rate of change is smaller than the set change value ε, it is ignored. On the other hand, if it is larger than the set change value ε, that is, if the degree of rise in temperature increases rapidly, it is determined that agglomeration has occurred. Therefore, at the increased time t2, an operation start signal for the agglomeration elimination operation is issued, and a predetermined elimination operation is performed based on the signal (S3).

The agglomeration elimination operation is performed, for example, by adjusting the amount of fuel supplied to the burner 6 to the granulation furnace 2.

On the other hand, if a similar situation occurs in the firing furnace 3, the amount of fuel supplied via the fuel supply pipe 15 is reduced, and the supply is stopped as necessary. When the pressure difference △P in the furnace inner layer 4 gradually recovers through such adjustment, it is detected that the pressure difference △P has returned to the original △Pa at time t3 in FIG. 2 (S4), and the agglomeration The elimination operation is stopped and the normal supply amount is restored (S5).

Incidentally, the duration of the abnormal fluctuation is about several seconds, and the abnormal differential pressure value is about 1/3 of ΔPa.

On the other hand, the temperature of the furnace inner layer 4 does not recover rapidly, and its temperature increases gradually.

Note that the agglomeration elimination operation in step 3 above includes adjusting the amount of raw material in each furnace and increasing the amount of raw material in each furnace, and the air introduction pipe 1 as the gas supplied to each furnace.
Similar effects can be obtained by adjusting the amount of fluidizing air introduced from step 4. At that time, if the temperature of the inner furnace layer 4 is rapidly lowered, this effect can be enhanced.

〔Effect of the invention〕

As can be seen from the detailed description of the embodiments above, the present invention detects when the pressure difference in the furnace inner layer becomes smaller than a set differential pressure value, and detects when the temperature rise change rate in the furnace inner layer becomes larger than the set change value. For example, a signal is output to eliminate agglomeration in the inner layer of the furnace, and the recovery of the pressure difference is detected and the elimination operation is stopped. Melation can be quickly resolved. Therefore, the granulation furnace and firing furnace can granulate and fire the cement raw material powder at an appropriate temperature. As a result, the quality of the produced cement clinker can be maintained at a high level. In addition, each time agglomeration occurs, a command is automatically issued to eliminate the agglomeration, which avoids equipment stoppage and suppresses adhesion on the furnace wall, improving cement clinker productivity. .

[Brief explanation of the drawing]

Fig. 1 is a sectional view of essential parts in one embodiment of a cement talin force production device to which the operation control method of the present invention is applied, Fig. 2 is a graph showing changes in pressure difference and temperature in the furnace inner layer, and Fig. 3 is a flowchart showing the agglomeration elimination operation. 2 - Granulation furnace, 3 - Calcining furnace, 17 - Differential pressure detector, 19 - Temperature sensor, 20 - Production furnace, α - Set differential pressure value, ε General constant change value. Patent applicant: Kawasaki Heavy Industries, Ltd. Agent: Patent attorney: Katsutoshi Yoshimura (and one other person) Figure 1' Figure 2 Between Ff1 (1) Figure 3

Claims (4)

[Claims] (1) In a cement production furnace such as a granulation furnace that granulates cement raw material powder etc. to produce cement clinker, or a fluidized bed type kiln that burns the granules, the inner layer of the above production furnace is It detects that the pressure difference has become smaller than the set differential pressure value, and it also detects that the rate of temperature rise change in the furnace inner layer has become larger than the set change value, and the furnace is activated based on both detection signals. Outputting a signal to start an elimination operation to eliminate agglomeration in the inner layer, detecting elimination of agglomeration in the furnace inner layer by recovery of the pressure difference in the furnace inner layer, and stopping the agglomeration elimination operation. An operation control method for a cement clinker manufacturing furnace, characterized in that: (2) The agglomeration elimination operation is performed by adjusting the amount of fuel supplied to the manufacturing furnace upon receiving the operation start signal.
A method for controlling operation in a cement clinker production furnace as described in Section 1. (3) The agglomeration elimination operation is performed by adjusting the amount of gas supplied to the production furnace upon receiving the operation start signal.
A method for controlling operation in a cement clinker production furnace as described in Section 1. (4) The agglomeration elimination operation is performed by adjusting the amount of cement raw material powder supplied to the production furnace upon receiving the operation start signal. Operation control method in cement clinker production furnace.