KR0181775B1 - Apparatus for precalcining cement raw meal for adjusting the amount of flowing air in the flowing bed - Google Patents

Abstract

The present invention is to provide a cement raw material plasticizer having a double bottom of the fluidized tube in order to uniformly control the flow rate inside and outside the fluidized bed in the fluidized bed calcining apparatus mainly for the decarbonation reaction of the raw material in the cement baking apparatus for producing a clinker, a semi-cemental product. It is to provide.

In the fluidized bed of the present invention. The cementitious plasticizer which can control the external flow rate is improved in the fluidized bed plasticizer whose main purpose is the decarbonation of the raw material during the cement firing process for producing the clinker, which is a semi-cemental product. The improvement is to form a uniform fluidized bed in the plasticizer. To this end, the lower portion of the flow pipe through which air passes from the blower is characterized by being configured by dividing the inner tube and the outer tube.

Description

In fluidized bed. Plasticizer of Cement Raw Material with Adjustable External Flow

The present invention is in a fluidized bed. The present invention relates to a plasticizer for cement raw materials capable of adjusting an external flow rate.

More specifically, in the fluidized bed calcining apparatus mainly for decarburization of raw materials, the cement raw material calcining apparatus having a double bottom portion of the fluidized tube in order to uniformly control the flow rate inside and outside the fluidized bed in the cement calcining apparatus for producing clinker, a semi-cemental product. It is about.

Usually, the calcining apparatus of cement raw materials consumes the most energy in the cement firing process for producing clinker, a finished cement product, and performs decarbonation reaction which requires about 80% to 95% of reaction to be completed before entering the rotary kiln. Device.

The cement firing process for producing a clinker, which is a cement semi-finished product, is described below with reference to FIG. 1.

First, the cement raw material is introduced into the gas outlet conduit of the preheater upper secondary top cyclones 12a, 12b, 12c, and 12d through the raw material supply conduits 9 and 10, and is preheated while suspended in hot gas. 11a, 11b, 11c, and 11d) are repeatedly lowered to the lower part of the preheater while the raw materials collected from the lower cyclones 14a, 14c and 14d are used for the decarbonation reaction which requires the most energy. It is introduced into the calcining furnace 3 through the raw material supply conduits 16 and 17.

On the other hand, the energy required for the decarbonation reaction is supplied to the gas furnace 3 through the fuel supply conduits 8a and 8b by the burners, mixed with the raw material in the lower fluidized bed portion 3a of the gas furnace 3, and (3) the combustion of fuel and the removal of raw materials while being transferred from the cooler (2) to the upper part of the furnace (3) by the combustion air added through the combustion air supply conduits (18a, 18b) to combust the fuel introduced into (3). The carbonic acid reaction takes place simultaneously. Here, symbol 3b is a conveying unit.

In the lean fluidized bed portion 3c, the combustion of the fuel and the decarbonation reaction of the raw materials are promoted while the raw material and the fuel of the large particles are recycled, and the complete combustion of the fuel and the decarbonation reaction of the raw materials are further maintained in the floating layer portion 3d for a long time. It is promoted, and the raw material discharged by air from the furnace 3 to the upper side is collected in the lower cyclone 15c, 15d and then introduced into the rotary kiln exhaust gas conduit and discharged from the rotary kiln 1. After the heat exchange is carried out again, the decarbonation reaction is completed, and the raw material collected in the lowermost cyclones (15a, 15d) is introduced into the rotary clean (1) and the fuel supply burner (1) in the rotary kiln (1) It is heated to about 1450 ℃ by the fuel injected by 7) is discharged to the cooler (2) after the klingering reaction is completed.

The cooler (2) cools the hot clinker with air while preheating the combustion air supplied to the rotary kiln (1) and the preheater and finally transfers the cooled clinker from the cooler (2) through the discharge conduit (19). Will be discharged.

In the cement firing process, a cement raw material calcining apparatus is a device attached to smoothly cause a calcining reaction in a rotary kiln by performing most of the decarbonation reaction of the raw materials in a calcining furnace.

The fluidized bed plasticizer forms a fluidized bed at the bottom of the furnace to uniformly mix raw materials and fuel so that the lead of the combusted fuel is transferred directly to the raw materials, thereby efficiently burning the fuel and decarbonizing the raw materials. It is a device that can suppress the formation of the coating in the furnace and use coal pellets and burn them completely.

Therefore, the formation of a uniform fluidized bed is a key factor in fluidized bed plasticizers.

A conventional fluidized bed plasticizer (Japanese Patent Laid-Open No. 3-45,020) of cement raw material is vertically coupled to an upper cylinder of a large cross section, a lower cylinder of a small cross section, and a funnel-shaped intermediate cylinder as illustrated in FIG. 4. In particular, the lower cylinder includes a fluidized bed portion 3a for flowing and mixing cement raw material and fuel, a raw material supply conduit 16 and 17 and a fuel supply conduit 8a and 8b and a fluidized bed for supplying raw materials and fuel to the fluidized bed portion 3a. Combustion air supply conduits 18a and 18b for supplying combustion air opened at a predetermined bed height of the section 3a are provided.

The flow rates of the fluidized bed portion 3a of the lower cylinder, the conveying portion 3b depending on the upper portion of the lower cylinder, and the floating layer portion 3d of the upper cylinder are 1.5 to 3 kPa, 10 to 20 kPa, and 3 to 5 kPa, respectively. It is an apparatus characterized by.

Conventional apparatus blows air into the fluidized bed through a nozzle using a blower (6) in the fluidized pipe bottom (20) to form a fluidized bed.

5 is a cross-sectional view taken along the line II-II of the lower portion of the flow tube of FIG.

When the air is blown in this way, in the large-capacity cement firing process, the inside air flow rate in the fluidized bed is faster than the outside air flow rate, resulting in non-uniform flow rate distribution in the fluidized bed. In this case, the amount of raw material discharged from the fluidized bed plasticizer is changed due to uneven mixing of raw materials and fuel, the formation of a coating by local combustion of fuel, and the change of the fluidized bed height. Temperature and pressure changes, as well as the incomplete combustion of fuel in the kiln and the frequent change of clinker reaction in the kiln, resulting in sudden fluctuations in the kiln motor ampere and sudden rise in CO, making it impossible to operate normally. Problems will arise.

FIG. 6 is a view illustrating an adhesion state of a coating on a lower portion of the flow tube of FIG. 5.

As can be seen in Figure 5 it can be seen that the inner flow rate in the fluidized bed is faster than the outside, so that the raw material and fuel in the fluidized bed is biased outward and cause the formation of a coating.

An object of the present invention is to form a uniform fluidized bed, which is a key element of a fluidizing device, by minimizing the variation of air flow in and out of a fluidized bed in a fluidized bed plasticizer of a cement firing process, particularly in a large-capacity fluidized bed plasticizer. By mixing fuel and raw materials and maintaining a stable fluidized bed height, it is intended to achieve stable operation without occurrence of abnormal processes by achieving uniform decarbonation and stable discharge of raw materials discharged from a fluidized plasticizer.

1 shows in a fluidized bed according to the invention. The overall schematic diagram of the cement firing apparatus with the plasticizer of cement raw material which can adjust an external flow volume.

2 is an overall schematic diagram of a calcining apparatus of cement raw material capable of adjusting the flow rate inside and outside the fluidized bed according to the present invention.

3 is a cross-sectional view taken along the line II of FIG. 2.

4 is an overall schematic view of a plasticizer of a conventional cement raw material.

5 is a cross-sectional view taken along the line II-II of FIG.

FIG. 6 is a schematic view showing a coating adhesion state under the fluid plate of FIG.

* Explanation of symbols for main parts of the drawings

1: rotary kiln 2: cooler

3: plasticizer 3a: fluidized bed part

3b: conveying part 3c: lean fluidized bed part

3d: floating layer part 4,5: blower

6: blower 7,8a, 8b: fuel supply conduit

9,10,16,17: Raw material supply conduit

11a, 11b, 11c, 11d, 12a, 12b, 12c, 12d, 13a, 13b, 13c, 13d, 14a, 14c, 14d, 15a, 15b, 15c, 15d

18a, 18b: combustion air supply conduit 19: exhaust conduit

20: lower portion of the flow tube 20a: inner tube

20b: appearance 20a ': first air supply conduit

20b ': second air supply conduit 21: damper

22,23: Exhaust Damper

In the fluidized bed of the present invention. The cementitious plasticizer which can control the external flow rate is improved in the fluidized bed plasticizer whose main purpose is the decarbonation of the raw material during the cement firing process for producing the clinker, which is a semi-cemental product. The improvement is to form a uniform fluidized bed in the plasticizer. To this end, the lower portion of the flow pipe through which air passes from the blower is characterized by being configured by dividing the inner tube and the outer tube.

According to the present invention, the inner pipe is connected to a first air supply conduit for supplying air from the blower, and the exterior is connected to a second air supply conduit branched to the first air supply conduit. 1 The air supply conduit is equipped with an additional damper to control the air volume.

Referring to the present invention in more detail based on the accompanying drawings as follows.

1 and 2 of the accompanying drawings in a fluidized bed according to the present invention. It is the overall schematic diagram of the plasticizer of cement raw material which can regulate external flow rate.

FIG. 2 is an enlarged view of only the plasticizer in FIG. 1, and according to FIG. 2, the raw material preheated in the cyclone is supplied to the lower fluidized bed portion 3a through the raw material supply conduits 16 and 17 and at the same time, the decarbonation of the raw material. The fuel providing the heat required for the reaction is supplied by the burner through the fuel supply conduits 8a and 8b, and the conveying part 3b has air for combusting the fuel from the cooler 2 for the combustion air supply conduit ( 18a and 18b flow the raw material and fuel mixed in the fluidized bed to the floating bed portion 3d.

According to the present invention, as shown in Fig. 2, the lower portion of the flow tube is configured in order to form a uniform fluidized bed.

That is, the inner tube 20a is divided into an outer tube 20b, and the inner tube 20a is connected to a first air supply conduit 20a 'that supplies air from the blower 6, and the outer tube 20b. ) Is connected to a second air supply conduit 20b 'branched from the first air supply conduit 20a'.

The first air supply conduit 20a is provided with a damper 21 for adjusting the amount of fluidized air.

Therefore, according to the present invention, it is possible to obtain a uniform fluidized bed by appropriately adjusting the flow rate inside and outside the fluidized bed.

3 is a schematic cross-sectional view taken along the line II of FIG. 2.

In FIG. 1, reference numerals 4 and 5 denote exhaust fans, 13a, 13b, 13c, and 13d are cyclones, and 22 and 23 are exhaust fan dampers.

According to the present invention, the fluidized calcining apparatus of the conventional cement firing process is provided in the cement firing process for producing the clinker, thereby obtaining the following effects.

That is, when operating with a conventional cement firing fluidized plasticizer, the temperature of the lowermost cyclone varies between 810 ° C and 1000 ° C as the pressure of the lower tube 20 varies from 800 mmAq to 1400 mmAq at intervals of about 14 to 15 minutes. Rotary kiln motor amps fluctuate rapidly, and CO rises sharply, making normal operation very difficult.

This resulted in frequent cyclone integration (6,5 times / month) and kiln shutdown (7 times / month) due to CO rise, daily clinker production decreased by 3.1%, and hot particle scattered due to pressure rise in fluidized bed plasticizers. And the risk of safety accidents was very high.

However, in the fluidized bed of the present invention. As a result of attaching the plasticizer fluidizing device for controlling the external flow rate, the pressure in the bottom of the fluidized bed was stabilized to 800mmAq, the integration number of the lowest cyclone was reduced to 0.3 times / month, and the rotary kiln was stopped by CO rise. Did not occur at all and the yield of daily clinker increased by 2.2%.

Thus in the fluidized bed of the present invention. It is possible to obtain a uniform fluidized bed, which is a key element of the plasticizer fluidizing device for cement raw material, which can control external flow rate, so that stable operation can be obtained without the occurrence of abnormal factors in the process according to the decarbonation of the raw material and the combustion reaction of fuel. It was found that the device.

In addition, even if a change in the amount of fluidization air in and out of the fluidized bed is required due to the operation between devices, it is possible to perform long-term continuous operation simply by adjusting the damper under continuous operation without stopping the process.

Claims (3)

In a fluidized bed calcining apparatus which mainly aims at decarbonation of raw materials during a cement firing process for producing clinker, a cement semi-finished product, In the fluidized bed, the lower part of the flow pipe through which air passes from the blower is divided into an inner pipe (20a) and an outer (20b) to form a uniform fluidized bed in the plasticizer. Cement raw material plasticizer that can control external flow rate. 2. The inner conduit (20a) is connected to a first air supply conduit (20a ') for supplying air from the blower, and the exterior (20b) is the first air supply conduit (20a'). Cement material calcining apparatus that can control the flow rate inside and outside the fluidized bed, characterized in that it is connected to the second air supply conduit (20b ') branched to). 3. The fluidized bed of claim 2, wherein the first air supply conduit (20a ′) is further provided with a damper (21) for adjusting the air volume. 4. Cement raw material plasticizer that can control external flow rate.