JPS6298186A - Plural system type powder material preheater - 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 a multi-system preheating device for powdered raw materials such as cement, alumina, lime, etc.

(Prior Art) Conventionally, powder raw material preheating devices have various configurations, including an exhaust gas system preheating device that mainly uses exhaust gas from the firing furnace, and a preheating device that uses high temperature exhaust air from a cooling device for fired products. Some systems have a combustion gas system preheating device and a combustion gas system preheating device that mainly uses the combustion gas generated by burning fuel in a calcining furnace.

As mentioned above, in the calcining method in which each preheating device is installed in parallel with the gas flow, the combustion furnace exhaust gas does not pass through the calciner located in the combustion gas system, so the fuel is combusted in the calciner. It has the advantage that it has excellent performance and that the calciner can be constructed compactly.

However, in the above-mentioned calcination method, the combustion gas system preheating device can calcinate the powder raw material to a high degree by adjusting the quantity of fuel supplied, but the exhaust gas system preheating device can perform a high degree of calcination at a temperature of about 1000 to 1100°C. The amount of heat that can be used for calcination of the powder raw material while the exhaust gas from the firing furnace introduced in the preheating device is lowered to a temperature of about 850-950'0 is reduced to 350-950'0. 45
The calcination rate of the powder raw material discharged from the exhaust gas system preheating device to the kiln is reduced because the amount of heat that can be used to preheat the powder raw material is insufficient until it is discharged after the temperature drops to around 0℃. If the amount of powdered raw material supplied to the exhaust gas system preheating device is restricted to such an extent that it cannot be heated to a high temperature or can be calcined to a high degree, excess heat that can be used for preheating will be discharged from the preheating device. The temperature of the scum will rise. In order to eliminate this inconvenience, it has been conventional practice to supply a part of the powdered raw material that passes through the lower part of the exhaust gas system preheating neck to the calcination furnace of the combustion gas system or to the gas duct near the calcination furnace. It is being said.

This conventional example will be specifically explained with reference to a system diagram of a cement raw material firing apparatus shown in FIG.

In the figure, ``■'' is a firing furnace for firing cement raw materials to obtain talinka, and 2 is a cooling device that cools talinka discharged from the firing furnace 1 by air flow.

The firing furnace 1 is connected to an exhaust gas system preheating device 3 that preheats the powder raw material with the exhaust gas from the firing furnace 1, and
A combustion gas system preheating device 4 is connected to the cooling device 2, which combusts fuel using the exhaust air from the cooling device 2 and preheats the powder raw material with the combustion gas. Further, the firing furnace 1 is connected to a cooling device 2, and high-temperature exhaust air from the cooling device 2 is sent into the firing furnace 1 for fuel combustion in the firing furnace 1.

The above exhaust gas system preheating device 3 will be explained. This exhaust gas system preheating device 3 has a vertical direction of f? It has powder separators CIl to CI4, such as cyclones, with heavy cyclones, and the waste discharge port of each powder separator and the gas inlet of the other powder separator above this powder separator are respectively connected by a gas duct) 7a. . In addition, the inlet cover 5 of the firing furnace 1 and the powder separator CI at the lowest stage
The gas inlet 4 is also connected by a gas duct) 7b. Furthermore, the gas outlet of the powder separator C11 on the top stage is connected to the exhaust gas fan 12a by a gas duct 7c, and the gas inlet of each of the powder separators mentioned above in the rail 6 and the powder outlet of the other powder separators above this powder separator are connected to the exhaust gas fan 12a by a gas duct 7c. The outlet and the raw material chute 13 respectively
connected by. Further, a raw material supply port 16 into which a powder raw material is introduced is provided in the gas duct 7a on the gas inlet side of the powder separator C++ at the uppermost stage.

Next, the combustion gas system preheating device 4 will be explained.

This combustion gas system preheating device 4 is constructed similarly to the above-mentioned exhaust gas system preheating device 3, and has powder separators 0 stacked vertically.
21 to C24 and an exhaust gas fan I2b, and gas ducts 7a, 7b, 7c and a raw material shunt 13 that connect these. In addition, in this combustion gas system preheating device 4, the powder separator C24 at the bottom t'r'
The gas inlet side gas duct i7b and this powder separator C2
A calciner 8 is interposed between the powder separator C73 and the powder discharge port located above the powder separator C73, and the calciner 8 burns fuel using the exhaust air from the cooling device 2 to preheat the powder raw material. This calciner 8 is connected to the cooling bag 2 by an air duct 9, and the calciner 8 is provided with an independent fuel supply device 10.

In addition, the powder separator C at the lowest stage of the combustion gas system preheating equipment 4
24 powder discharge ports are connected to the inlet layer 5 of the firing furnace 1 by a raw material chute 14b, and the exhaust gas system preheating device 3
The powder discharge port of the powder separator CI4 at the lowest stage is connected to the middle part of the raw material chute 14b from the powder discharge port of the powder separator C24 by a raw material chute 14a.

Further, a raw material chute 13 from the powder discharge port of the second stage powder separator C from the bottom in the exhaust gas system preheating device 3
The middle part is connected to the middle part of the raw material chute 13 from the powder discharge port of the second-stage powder separator C= from the bottom of the combustion gas system preheating device 4 by a branch chute 15 .

The high-temperature exhaust air that has cooled the tarinka in the cooling device 2 is burned in the firing furnace 1 to become exhaust gas, and in the exhaust gas system preheating device 3, it is sucked by the exhaust gas fan 12a and sent from the powder separator Cs4 at the lowest stage. The powder is flowed to the upper powder separator C. In addition, the combustion gas system preheating device 4
In this case, the exhaust air from the cooling device 2 is sent to the calciner 8.
This gas is sucked by the exhaust gas fan 12b and flows from the lowest powder separator C24 to the uppermost powder separator C21 (the flow of exhaust gas is indicated by solid arrows in the figure).

On the other hand, the powder raw materials inputted from each raw material supply port 16.16 are heated by the high-temperature gas and then
, 4 top stage powder separator CO.

The powder flows from the C force toward the lower stage, is fired in the firing furnace 1 to become Talin force, is cooled in the cooling device 2, and is transferred to the next process (the flow of the powder raw material is indicated by the broken line arrow in the figure).

In the above case, a part of the preheated powder raw material discharged from the second-stage powder separator Cr3 from the bottom in the exhaust gas system preheating device 3 is branched and supplied to the calciner 8 of the combustion gas system preheating device 4. Therefore, the quantitative ratio of the powder raw material fed from the powder separator C13 to the gas inlet side gas duct 7b of the lowest stage powder separator CI4 is reduced. For this reason, the powder raw material supplied to the firing furnace 1 from the lowest stage powder separator C in the exhaust gas system preheating device 3 is transferred to the gas duct) 7a.
A high degree of calcination is achieved during the flow inside. In addition, in the combustion gas system preheating device 4, the fuel supply device 10 is connected to the calciner 8.
Powder raw materials can be calcined to a high degree by adjusting the fuel supplied inside.

(Problems to be Solved by the Invention) By the way, in a preheating device consisting of a plurality of systems as described above, originally there are an exhaust gas system preheating device 3 and a combustion gas system preheating device 4.
are arranged independently for each device. For this reason, the powder separator C in the second stage from the bottom of the exhaust gas system preheating device 3
t3 and the calciner 8 of the combustion gas system preheating device 4 is characterized by a relatively large horizontal distance.In particular, the combustion gas system preheating device 4 is added to the existing exhaust gas system preheating device 3. Branch chute 15 when installing
The horizontal distance of is a large dimension.

In this case, in order to prevent the powder raw materials from accumulating in the branch chute 15, it is necessary to make the inclination angle with respect to the horizontal plane somewhat large, for example, 50 to 55 degrees or more. A large vertical distance is required between both devices. However, if such a large vertical distance is attempted, the overall size of the device increases. Furthermore, when another preheating device is newly installed, there is a problem in that the arrangement of each powder separator and calciner is severely restricted due to the necessity of ensuring a predetermined angle for the branch chute 15.

Furthermore, by additionally installing the combustion gas system preheating device 4 to the existing exhaust gas system preheating device 3, the capacity of the entire firing device can be increased, for example, by up to about 2.5 times. When carrying out such modification work, it may also be attempted to reduce the pressure loss of the existing exhaust gas system preheating device 3 and reduce the driving force of the exhaust gas fan 12a to save energy.

However, the amount of exhaust gas introduced from the firing furnace 1 into the exhaust gas system preheating device 3 is determined mainly by the temperature and degree of calcination of the powder raw material supplied to the firing furnace 1 from the preheating devices 3.4 of both systems. However, the amounts of gas passing through the preheating devices of both systems are not mutually adjusted. For this reason,
Once the degree of capacity increase due to the above modification is determined, the amount of gas introduced from the firing furnace 1 to the existing exhaust gas system preheating device 3 is determined, and accordingly, the pressure loss within the exhaust gas system preheating device 3 is determined. There is a relationship between Therefore, if you try to increase the capacity of the preheating device as a whole, there is a risk that the pressure loss in the exhaust gas system preheating device 3 will increase, and conversely, if you try to reduce the pressure loss, you will have to limit the increase in capacity. I was in a situation.

(Object of the Invention) This invention was made in view of the above-mentioned circumstances, and it connects the proper location of the exhaust gas system preheating device and the proper location of the combustion gas system preheating device, and connects one of these devices to the other. When conveying the powder raw material to the connecting part, the structure is designed to prevent the powder raw material from accumulating at this connection part, and also to prevent the overall size of the device from increasing, and to reduce the pressure loss of the exhaust gas passing through the exhaust gas system preheating device. The purpose is to reduce

(Structure of the Invention) A feature of the present invention for achieving the above object is that the gas inlet side of the powder separator in the second stage from the bottom of the exhaust gas system preheating device is connected to the gas inlet side of the combustion gas system preheating device. The powder separation means is connected to the upper passage through a powder separation means, the powder discharge port of this powder separation means is connected to the lower passage of the combustion gas system preheating device, and an air volume adjustment means is provided for the powder separation means. It is in.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2. The basic configuration of these embodiments is the same as that of the conventional example. Therefore, the same components are given the same reference numerals, and the explanation thereof will be omitted.

FIG. 1 shows a first embodiment.

The gas duct 7ai on the gas inlet side of the powder separator Cr3 in the second stage from the bottom in the exhaust gas system preheating device 3 is supplied through the raw material chute 13 from the powder outlet of the powder separator CI2 in the third stage from the bottom. After the powder raw material is dispersed in the hot gas rising inside the gas duct 7a,
A part of the powder raw material is mixed with natural gas in the combustion gas system preheating device 4
The powder separator C22 in the third stage from the bottom of the gas duct) 7a and the combustion gas system preheating device 4 is
and are connected by a connecting duct 18.

An inertial powder separator CO1 serving as powder separation means is interposed in the middle of the connection duct 18. This inertial powder separator C
The powder outlet of o1 is 2 from the bottom of the combustion gas system preheating device 4.
It is connected via a raw material chute 19 to a midway portion of the raw material chute 13 from the powder discharge port of the powder separator CZS in the second stage.

In addition, the connecting duct 18 on the gas outlet side of the inertial powder separator Cot has a wind i that opens and closes the connecting duct 18:
A damper 20 serving as g1 node means is provided. Furthermore, a damper 21 is provided in the air duct 9 leading to the calciner 8 of the combustion gas system preheating device 4 .

Then, the powder raw material input from the raw material supply port 16 of the exhaust gas system preheating device 3 is transferred to the powder separator CI3 together with the gas.
and is branched and supplied to the inertial powder separator Cot, where it is separated into gas and powder raw material, and this powder raw material is charged into the calciner 8 of the combustion gas system preheating device 4.

Furthermore, the exhaust gas from the inertial powder separator Co1 passes through the damper 20 and is introduced into the powder separator C22.

The amount of hot gas and powder raw material branched and distributed from the exhaust gas system preheating device 3 to the combustion gas system preheating head 4 in this way is preferably 10 to 40% of the amount of each introduced into the exhaust gas system preheating device 3. It is. These branch distribution amounts are adjusted by the damper 20 provided in the connecting duct 18 in accordance with the temperature equilibrium state in both systems.

FIG. 2 shows a second embodiment, in which an exhaust gas system preheating device 3 and a combustion gas system preheating device 4 are arranged in five stages of powder separation means C+o, C+a and C20, stacked downward, respectively.
It has C24.

The powder separation means installed in the connecting duct 18 connecting the exhaust gas system preheating device 3 and the combustion gas system preheating device 4 is a cyclone powder separator CO2, and the gas discharge port of this cyclone powder separator CO2 is It is connected by a connecting duct 18 to the gas inlet side gas duct 7a of the powder separator C2+ in the fourth stage from the bottom of the gas system preheating device 4. In addition, the powder discharge port of this cyclone powder separator CO2 is located in the second stage powder separator C2 from the bottom of the combustion gas system preheating device 4.
3) Insert the raw material into the gas inlet side gas duct) 7a, -) 2
Connected by 3.

Furthermore, the powder separator CA at the lowest stage of the exhaust gas system preheating device 3
An independent fuel supply device 24 is provided on the gas inlet side gas duct 7b.

Therefore, the powder raw material branched and supplied to the cyclone powder separator CO2 together with the gas from the second stage gas duct 7a from the bottom of the exhaust gas system preheating device 3 is separated from the gas in the powder separator CO2, and then the powder separator It is discharged to the gas inlet side gas duct) 7a of C23, and is the raw material supply port of the combustion gas system preheating device 4.

It is supplied to the calcining furnace 8 via the powder separator C23 together with the powder raw material input from 6. Then, a high degree of calcination is achieved in the calcination furnace 8.

In addition, the powder raw material input from the powder separator C in the second stage from the bottom of the exhaust gas system preheating device 3 to the gas inlet side gas duct) 7b of the powder separator CK in the lowest stage flows through the inside of the gas duct) 7b. By supplying fuel as necessary from the fuel supply device 24 into the ascending exhaust gas from the firing furnace 1 and combusting it, further calcination is achieved. After being calcined in this manner, it is discharged to the firing furnace 1 together with the calcining raw material in the combustion gas system preheating device 4.

Note that the lowermost powder separator C of the exhaust gas system preheating device 3
The fuel supply device 2 is connected to the gas duct 7b on the gas inlet side of V@.
4, the gas duct 7b may be constructed in the form of a calciner, or may be connected to the cooling device 2 by an air duct 9, similar to the calciner 8 of the combustion gas system preheating device 4. good.

In addition, the number of preheating devices that make up each system of the exhaust gas system preheating device 3 and the combustion gas system preheating device 4, the type of powder separation means installed in the connecting duct 1.8, and the powder separation that makes up each preheating device The type and number of stages of the vessel, the type of calcining furnace, etc. are not limited to those in each of the above embodiments.

(Effects of the Invention) According to the present invention, the gas inlet side of the powder separator in the second stage from the bottom of the exhaust gas system preheating device is connected to the upper path of the combustion gas system preheating device via the powder separation means. At the same time, because the powder discharge port of this powder separation means is connected to the path at the bottom of the combustion gas system preheating device, a part of the powder raw material input into the exhaust gas system preheating device is once separated into powder by the flow of exhaust gas from the kiln. The powder raw material and the gas separated therein are respectively supplied to appropriate locations in the combustion gas system preheating device. In other words, since the powder raw material is transported from the exhaust gas system preheating device side to the powder separation means by the flow of exhaust gas, even if the horizontal distance from the exhaust gas system preheating device side to the powder separation device is sufficiently large, there will be a This prevents the operation from being hindered by the accumulation of powder raw materials. Therefore, if necessary, the powder separating means is placed near the combustion gas system preheating device by sufficiently separating it from the exhaust gas system preheating device by a horizontal distance, and the powder discharge port of the powder separation means is connected to the combustion gas system preheating device. can be connected at large angles of inclination as required by the lower path of the Therefore, the powder raw material is prevented from accumulating even during this route. As a result, when the exhaust gas system preheating device and the combustion gas system preheating device are connected, the powder raw material is prevented from accumulating at the connecting portion. Moreover, in this case, since there is no need for a large height difference between the exhaust gas system preheating device and the combustion gas system preheating device, it is possible to prevent these devices from increasing in size as a whole.

Moreover, in order to transport a part of the powdered raw material input into the exhaust gas system preheating device to the combustion gas system preheating device side, the amount of heat that can be used for preheating is surplus compared to the amount of heat that can be used for calcination of the powdered raw material as described above. This system is designed to use a part of the firing furnace exhaust gas, which is discharged from the lowermost calcining area in the exhaust gas system preheating device and flows to the upper preheating area. It is extracted from the exhaust gas system preheating device, accompanied by the preheated raw material just before being supplied, to the combustion gas system preheating device via the powder separation means.

At this time, since an air volume adjustment means is provided for the powder separation means, the air volume adjustment means moves the exhaust gas system preheater from the combustion gas system to the exhaust gas system preheater in accordance with the temperature equilibrium state of the exhaust gas system preheater and the combustion gas system preheater. The amount of hot gas and powder raw material branched to the preheating device can be vtimed.

Therefore, it is possible to achieve a high degree of calcination of the powder raw material using the re-preheating device, and it is also possible to maintain a balance between the amount of heat required for calcination and preheating in these re-preheating devices.

In addition, as the hot gas moves from the exhaust gas system preheating device to the combustion gas system preheating device, the amount of exhaust gas passing through the upper part of the exhaust gas system preheating device decreases, resulting in a pressure loss in the upper part of the exhaust gas system preheating device. reduction is achieved.

In particular, when a fuel supply device is installed in the lowest stage gas duct of the exhaust gas system preheating device, it is possible to replenish the insufficient amount of heat for calcination in the exhaust gas system preheating device.
It is necessary to reduce the amount of powder raw material and gas that are branched and supplied to the combustion gas system preheating device. That is, by adjusting the distribution of fuel supplied to the re-preheating device, the amount of powder raw material and gas branched from the exhaust gas system pre-heating device to the combustion gas system pre-heating device, and therefore the amount of hot gas passing through the upper part of the re-preheating device. As a result, the sharing of preheating and calcination work for the powder raw materials in both systems can be adjusted over a wide range, and economical equipment design and operation can be achieved.

[Brief explanation of drawings]

1 and 2 show embodiments of the present invention, FIG. 1 is a system diagram of a cement raw material firing apparatus in the first embodiment, FIG. 2 is a diagram corresponding to FIG. 1 in the second embodiment, FIG. 3 is a diagram corresponding to FIG. 1 in a conventional example. 1. Firing furnace, 2. Cooling device, 3. Exhaust gas system preheating device, 4. Combustion gas system preheating device, 7a” gas duct, 7b--Gas duct, 8-. Calcining furnace, 10.- Fuel supply. Apparatus, 13.--Raw material chute, 14a.-Raw material chute, 14b-.Raw material chute, 18..Connection duct, 1
9... Raw material chute, 20... Damper, 23... Raw material chute, 24... Fuel supply device, C: IO"' C14
@ψ powder separator, C2o-024...powder separator,
COt number/inertial powder separator (powder separation means), CO
2. Φ cyclone powder separator (powder separation means).

Claims (1)

[Claims] 1. A firing furnace for firing powder raw materials, a cooling device for cooling the fired product discharged from the firing furnace with air flow, and an exhaust gas system for preheating the powder raw materials with exhaust gas from the firing furnace. A preheating device and a combustion gas system preheating device for combusting fuel using the exhaust air from the cooling device and preheating the powder raw material with the combustion gas are provided, and each of the preheating devices are stacked vertically and connected to each other. Each has a plurality of connected powder separator groups, and the powder discharge ports of the lowest stage powder separator of each preheating device are respectively connected to the firing furnace, while the combustion gas system is located at the lowest stage of the combustion gas system preheating device. A calciner is installed between the gas inlet of a powder separator and the powder outlet of another powder separator above this powder separator to preheat the powder raw material by burning fuel using exhaust air from the cooling device. In the interposed powder raw material firing device, the gas inlet side of the second-stage powder separator from the bottom of the exhaust gas system preheating device is connected to the upper path of the combustion gas system preheating device via a powder separation means. A multi-system powder raw material preheating device characterized in that the powder discharge port of the powder separation means is connected to a lower passage of a combustion gas system preheating device, and an air volume adjustment device is provided for the powder separation device. 2. The multi-system powder raw material preheating device according to claim 1, characterized in that an independent fuel supply device is provided on the gas inlet side of the powder separator at the lowest stage of the exhaust gas system preheating device. 3. A multi-system powder raw material preheating device according to claim 1 or 2, characterized in that the powder separation means is a cyclone powder separator.