JP2001294456A - Heat treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treating device capable of stably heating a raw material in a calcining furnace and improving the throughput. SOLUTION: The heat treating device is provided with a 1st preheating part 12 for heating the raw material before firing, the calcining furnace 17 for decomposing prescribed components in the raw material by further heating the raw material heated in the 1st preheating part 12 in a prescribed space, a 1st gas passage 19 for introducing a gas into the calcining furnace from a place different from that in the firing part 10 to turn the gas in the calcining furnace 17 and a 2nd gas passage 20 for introducing the gas into the calcining furnace 17 from a place different from that in the firing part 10 to raise the gas in the calcining furnace 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus for firing raw materials, for example, used for cement production.

[0002]

2. Description of the Related Art As a heat treatment apparatus for firing raw materials, there is an apparatus used for producing cement, for example. In general, a heat treatment apparatus for manufacturing cement produces a chemical change by firing a prepared raw material in a firing section such as a rotary kiln, thereby converting the raw material into a hydraulic compound required as cement. In such a heat treatment apparatus, a preheating unit (preheater) for preheating the raw material before firing may be provided. As the preheating method, a so-called SP (suspension preheater) method and an NSP (new suspension preheater) method are used. Two types are known.

[0003] Of the two types described above, the SP type heat treatment apparatus has a plurality of heat exchangers vertically connected upstream of the flow of the raw material from the firing section, and feeds the raw material input from the upper stage through the firing section. The discharged high-temperature exhaust gas is blown up from below, and the raw material and the exhaust gas undergo heat exchange while floating, so that the heated raw material is introduced into the firing section.

On the other hand, the heat treatment apparatus of the NSP method
In addition to the heat exchanger connected in the vertical direction like the P method,
Predetermined space for burning fuel (hereinafter referred to as calciner)
The components of the raw materials are further heated at a high temperature in this calcining furnace to decompose them before the raw materials are put into the firing section.
It is configured so that the reaction speed of the raw material can be increased as compared with the system.

[0005]

However, in the heat treatment apparatus of the NSP method as described above, the processing capacity is greatly improved as compared with the SP method. In comparison, the size of the preheating section becomes larger. Therefore, for example, even when the throughput is temporarily reduced, it is difficult to flexibly cope with a variation in the throughput, for example, the heating of the raw material in the preheating unit requires a certain amount of energy or more. Therefore, a heat treatment apparatus combining two preheating methods, the SP method and the NSP method, has been proposed.

FIG. 4 shows a schematic configuration of a heat treatment apparatus that combines the SP method and the NSP method. This heat treatment apparatus employs an SP method preheating unit (hereinafter referred to as S) for heating a raw material before firing. And a NSP preheating unit (hereinafter referred to as an N-type preheating unit) 32 which heats the raw material before firing and decomposes a predetermined component of the raw material in a calciner 31 thereof. ing. Further, the exhaust gas from the firing unit 33 flows through the S-type preheating unit 30, and the gas from a location different from the firing unit 33 flows through the N-type preheating unit 32. According to this heat treatment apparatus, for example, when the throughput is temporarily reduced, the S-type preheating unit 30
The processing capacity can be easily changed, for example, by using only one of the N-type preheating unit 32 and the N-type preheating unit 32. Moreover, the reaction rate of the raw material can be increased by decomposing predetermined components of the raw material in the calciner 31 of the N-type preheating section 32. From these, it is relatively easy for the heat treatment apparatus to appropriately determine efficient operating conditions in accordance with the processing amount, and it is possible to easily cope with fluctuations in the processing amount and improve the processing capacity. There is an advantage.

However, in the above-described conventional heat treatment apparatus, gas from a location different from the sintering section 33 flows to the N-type preheating section 32. Unable to lift raw materials,
The raw material is not stably heated and the processing capacity is reduced. However, if an attempt is made to supply a large amount of gas in order to lift the raw material in the calciner 31, the supply cost of the gas is increased, or the flow rate of the gas in the N-type preheating section 32 is increased due to an increase in the gas flow rate. However, the processing ability is likely to be deteriorated.

The present invention has been made in view of the above-mentioned circumstances, and provides a heat treatment apparatus capable of stably heating a raw material in a calciner and improving the processing capacity. With the goal.

[0009]

Means for Solving the Problems In order to solve the above problems, the invention according to claim 1 is directed to a heat treatment apparatus for firing a raw material in a firing section while moving the raw material from a charging side to a discharging side. A first preheating section for heating the raw material, a calciner for further heating the raw material heated in the first preheating section in a predetermined space to decompose a predetermined component in the raw material, A first gas passage for guiding gas from a location different from the firing section to the calciner so that the gas turns.
A technique including a second gas passage for introducing gas from a location different from the firing section to the calciner so that the gas rises in the calciner is employed. In this heat treatment apparatus, the first
Since the gas from the gas passage causes a swirling flow in the calciner, the raw materials flow uniformly in the calciner and the raw material is uniformly heated, and the gas from the second gas passage increases the flow rate. Is generated, the force of lifting the raw material in the calciner works sufficiently, and the raw material is stably heated.

According to a second aspect of the present invention, in the heat treatment apparatus of the first aspect, at least one of the first and second gas passages is provided with a gas heating means for heating a gas. Is adopted. In this heat treatment apparatus, the temperature of the gas introduced from the first or second gas passage becomes high by being heated by the gas heating means, so that the fuel burns stably.

According to a third aspect of the present invention, in the heat treatment apparatus according to the first or second aspect, the first and second gas passages extend from a cooling unit for cooling the fired raw material to the calcining furnace. The technology that is arranged to guide the gas to the air is employed. In this heat treatment apparatus, the first and second gas passages are formed so as to guide gas from the cooling furnace.
The gas in the cooling section can be effectively used for processing in the second preheating section.

According to a fourth aspect of the present invention, in the heat treatment apparatus according to any one of the first to third aspects, a gas discharged from the firing section is flowed to heat the raw material before firing. A technology having two preheating units is employed. In this heat treatment apparatus, a first preheating section for heating the raw material before firing,
A calcining furnace for further heating the raw material heated in the first preheating section in a predetermined space to decompose predetermined components in the raw material, and a second for heating a raw material before firing by flowing gas discharged from the firing section. In order to provide a preheating unit, for example, when the processing amount temporarily decreases, such as using only one of the first or second preheating unit, by appropriately determining efficient operating conditions according to the processing amount, It is easy to change the processing capacity.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a heat treatment apparatus according to the present invention will be described below with reference to the drawings. The heat treatment apparatus of the present embodiment is used for firing a raw material in a cement manufacturing process, and a raw material pulverized into a predetermined shape by a pulverizer or the like and mixed is supplied from above.

As shown in FIG. 1, the heat treatment apparatus includes a baking section 10 such as a rotary kiln that heats at a predetermined temperature. And change it into a hydraulic compound required for cement.

Further, the heat treatment apparatus comprises an S-type preheating section 11 for heating the raw material before firing,
Similarly to 1, an N-type preheating section 12 is provided for heating the raw material before firing and further decomposing a predetermined component in the raw material. The S-type preheating unit 11 has a space 13 connected in multiple stages called a cyclone, and the exhaust gas from the firing unit 10 flows into each space 13 in order from the bottom, and is injected from the first input unit 14 and falls. By exchanging heat between the raw material and the exhaust gas, the raw material before firing is heated. Each space 13 of the S-type preheating unit 11 is connected to each other by a passage, and as shown by a dotted line in the figure, each raw material input from the first input unit 14 is blown up by the exhaust gas G1 from below, and The space 13 is moved and gradually heated to a high temperature.

The N-type preheating section 12 is provided with the S-type preheating section 1 described above.
1 and, like the S-type preheating unit 11, the second charging unit 1
The raw material before firing is heated by exchanging heat between the raw material charged and dropped from 5 and a predetermined gas G2.
It has a space 16 connected in multiple stages. Further, the N-type preheating section 12 is provided with a calciner 17 for burning fuel to decompose components in the raw material.

The calcining furnace 17 is for burning finely pulverized coal (pulverized coal) with a burner 18 to heat the raw material that has fallen and decomposing the components (limestone in this case) in the raw material. In addition, a calciner 17 is provided below the calciner 17.
First gas passage 1 for supplying a predetermined gas G2 to the inside
9 and the second gas passage 20 are connected.

As shown in FIG. 2, the first gas passage 19 forms a spiral space (vortex chamber 21) below the calciner 17 and passes through the vortex chamber 21 into the calciner 17. The supplied gas G2 is swirled in the calciner 17. Returning to FIG. 1, the second gas passage 20 is provided to be branched from the first gas passage 19 here, one end of which is connected to the lower part of the calciner 17, and the gas G flows into the calciner 17 in the ascending direction.
2 is provided.

Also, the first and second gas passages 19, 20
Is formed to guide the gas G2 discharged from the cooling unit 22 for cooling the fired raw material to the calcining furnace 17. Further, the gas G2 is supplied to the second gas passage 20 with the calciner 1
A burner 23 for heating before feeding to 7 is installed.

The cooling unit 22 is provided with, for example, a slidable stepped floor surface, and is configured to exchange heat on the floor surface to cool the fired raw material. Further, a part of the gas heated by the heat exchange is caused to flow to the baking section 10, and another part is caused to flow to the above-described first gas passage 19 (and the second gas passage).

Further, in the heat treatment apparatus of the present embodiment, a part or all of the raw material heated in the S-type preheating section 11 flows into the calciner 17 and is reheated. The amount of raw material flowing from the S-type preheating section 11 to the calciner 17 can be arbitrarily adjusted by adjusting means (not shown).

Next, the operation of the heat treatment apparatus having the above configuration will be described. In the production of cement, a mixed raw material mainly composed of limestone is used, and a raw material that has been previously prepared and pulverized into a powder form is supplied from the first and second charging sections 14 and 15 into an S-type and a raw material, as shown in FIG. N-type preheating unit 11, 1
2 respectively. At this time, the S-type preheating unit 11
The ratio of the amount of the raw material to be supplied to the N-type preheating section 12 and the amount of the raw material to be supplied to the N-type preheating section 12 is determined in advance based on the production amount at that time so that the raw material can be most efficiently fired.
Here, it is assumed that the total amount of the raw material heated by flowing through the S-type preheating section 11 is adjusted to flow into the calciner 17.

The raw material supplied to the S-type preheating unit 11 sequentially moves through a plurality of spaces 13 while being floated by the exhaust gas G1 from the firing unit 10, and for example, 1000 to 110
It is gradually heated by heat exchange with the exhaust gas G1 having a high temperature of 0 ° C., for example, 800 to 900 ° C. in the lowermost space 13.
Temperature.

Similarly, the raw material supplied to the N-type preheating section 12 is heated by moving sequentially through the plurality of spaces 16 while being floated by the gas G2 from the cooling section 22. The temperature of the gas G2 at the time when the gas G2 is discharged from the cooling unit 22 is, for example, 700 to 800 ° C., and when the gas G2 is heated in the calcination furnace 17, the temperature of the gas G2 becomes higher and exchanges heat with the raw material. Become.

The raw materials heated in the S-type and N-type preheating sections 11 and 12 flow into a calciner 17 and are further heated in the calciner 17. In the present embodiment, a swirling flow is generated in the calciner 17 by the gas G2 from the first gas passage 19, as shown in FIG. Then, the raw materials in the calciner 17 are caused to flow together by this swirling flow, and the raw materials are heated relatively uniformly in the calciner 17 without unevenness. Further, the gas G2 from the second gas passage 20 causes the calciner 1
The ascending flow is generated in the inside 7, and the force for lifting the raw material in the calciner 17 sufficiently works, so that the raw material is stably heated. The gas G2 from the second gas passage 20 is heated (for example, 1000 to 1100) by the burner 23 just before the calciner 17.
° C), and an ascending flow is efficiently generated by the heated gas G2, and the fuel is stably burned in the calcining furnace 17. Therefore, most of calcium carbonate, which is a main component of limestone in the raw material, is surely decomposed into calcium oxide and carbon dioxide in the calciner 17.

The raw material that has passed through the calciner 17 subsequently flows to the firing section 10. The inside of the firing unit 10 is, for example, 1450.
The raw material is heated to a high temperature of about ℃, and the raw material is further heated to a higher temperature while gradually moving to the discharge side. In the firing section 10, a chemical reaction proceeds between the plurality of raw materials through several stages. Then, the compound generated in the baking section 10 is rapidly cooled in the cooling section 22 and is discharged from the cooling section 22 as a compound called a clean car. This compound is a hydraulic compound required for cement, and thereafter, the compound is finely pulverized into fine powder by a pulverizer.

In the heat treatment apparatus of the present embodiment, the SP type S-type preheating unit 11 and the NSP type N-type preheating unit 12 are provided in parallel. Alternatively, if only one of the N-type preheating units 11 and 12 is used, it is possible to easily cope with a change in the processing amount. Also, for example, since the size of each space 13 in the S-type preheating section 11 through which the raw material passes is substantially the same as that of the apparatus having only the SP-type preheating device, the adjustment of the energy amount is the same as that of the apparatus using only the SP method. And can be easily controlled. As described above, the heat treatment apparatus can easily cope with a change in the throughput and improve the processing capacity.

According to the heat treatment apparatus of this embodiment,
The gas G2 from the first gas passage 19 causes a swirling flow in the calciner 17, so that the raw materials flow uniformly in the calciner 17, and the raw materials are heated relatively uniformly. In addition, the raw material is sufficiently lifted in the calciner 17 by the upward flow of the gas G2 from the second gas passage 20, and the raw material is stably heated. Therefore, the main components in the raw material are sufficiently decomposed in the calciner 17, and the
The reaction rate of the raw materials in the process can be increased, and the processing capacity can be improved.

The gas G2 flowing through the second gas passage 20
Is heated to a high temperature by the burner 23, so that the calciner 1
The temperature of the gas G2 supplied to the inside 7 becomes sufficiently high, the fuel is stably burned in the calciner 17, and the efficiency of the decomposition treatment of the components in the raw material is improved. In addition, the gas G2 itself generates sufficient buoyancy by being heated by the burner 23, and its volume also increases. For this reason, it is easy to improve the processing capacity without breaking the flow balance of the fluid in the entire N-type preheating unit 12. Further, since the gas G2 guided to the calciner 17 through the first and second gas passages 19 and 20 uses the gas of the cooling unit 22, the gas G2 is effectively used to form the gas G2 in the N-type preheating unit 12. Processing can be performed, and the energy cost required for gas supply can be reduced.

The various shapes and combinations of the constituent members shown in the above-described embodiments are merely examples, and various changes can be made based on design requirements without departing from the gist of the present invention. For example, in the present embodiment, SP
The system and the NSP-type preheating device are each configured as one. However, the present invention is not limited to this. For example, another combination such as one SP-type preheating device and two NSP-type preheating devices is provided. May be. Also, the second
The gas passage 20 only needs to generate an upward flow in the calciner 17, and the gas may be supplied into the calciner 17 from obliquely below the calciner 17. Further, the gas supplied to the N-type preheating unit 12 is not limited to the gas using the gas taken out from the cooling unit 22, but may be configured to use a high-temperature gas from another device. In this case, when a sufficiently high temperature gas is supplied, the burner 23 shown in the present embodiment is used.
It is also possible to adopt a configuration that does not use.

[0031]

As described above, according to the present invention, the following effects can be obtained. In the heat treatment apparatus according to the first aspect, since the swirling flow is generated in the calcining furnace by the gas from the first gas passage, the raw materials in the calcining furnace flow by the swirling flow, and the raw material is relatively reduced. Heated uniformly and evenly. In addition, the upward flow is generated by the gas from the second gas passage, and the force for lifting the raw material in the calciner works sufficiently, so that the raw material can be stably heated.
Therefore, the main component in the raw material can be sufficiently decomposed in the calcining furnace to increase the reaction rate of the raw material, thereby improving the processing capacity.

In the heat treatment apparatus according to the second aspect, the temperature of the gas introduced from the first or second gas passage becomes high.
The fuel burns stably, and the efficiency of the decomposition treatment of the components in the raw material is further improved. In addition, since the buoyancy of the gas is sufficiently generated by heating, the processing capacity can be improved without breaking the flow balance of the fluid in the first preheating unit.

In the heat treatment apparatus according to the third aspect, since the gas used in the first preheating section is guided from the cooling section, the gas can be effectively used to perform the processing in the first preheating section. It is possible to suppress the energy cost required for the supply of water.

In the heat treatment apparatus according to the fourth aspect, for example, when the processing amount is temporarily reduced, only one of the first and second preheating units is used. , The processing capacity can be easily changed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a heat treatment apparatus according to the present invention.

FIG. 2 is a diagram showing a gas flow in a first gas passage of FIG.

FIG. 3 is a view showing a gas flow in the calcining furnace of FIG.

FIG. 4 is a configuration diagram showing a conventional heat treatment apparatus.

[Explanation of symbols]

 G1 exhaust gas G2 gas 10 firing unit 11 S-type preheating unit (second preheating unit) 12 N-type preheating unit (first preheating unit) 17 calciner 18 burner 19 first gas passage 20 second gas passage 21 vortex chamber 22 Cooling unit 23 Burner (gas heating means)

Claims (4)

[Claims] 1. A heat treatment apparatus for firing a raw material in a firing section while moving the raw material from an input side to a discharge side, wherein the first preheating section heats the raw material before firing, and the first preheating section heats the raw material before firing. A calcining furnace that further heats the raw material in a predetermined space to decompose a predetermined component in the raw material, and the calcining is performed from a location different from the calcining unit so that a gas is swirled in the calcining furnace. A first gas passage that guides gas to the furnace; and a second gas passage that guides gas to the calciner from a location different from the firing unit so that the gas rises in the calciner. Heat treatment equipment. 2. The heat treatment apparatus according to claim 1, wherein gas heating means for heating a gas is provided in at least one of the first and second gas passages. 3. The gas passage according to claim 1, wherein the first and second gas passages are arranged to guide gas from a cooling unit for cooling the fired raw material to the calciner. The heat treatment apparatus according to claim 2. 4. The apparatus according to claim 1, further comprising a second preheating section for flowing a gas discharged from the firing section to heat the raw material before firing. Heat treatment equipment.