JP2023019636A - Method and device of drying carbon black - Google Patents

Abstract

To provide a method and a device of drying carbon black, capable of accurately controlling a temperature and an amount of high temperature gas being supplied to a dryer.SOLUTION: The method and the device of drying carbon black use a dryer 20 having an inner cylinder 21 and an outer cylinder 22 to supply carbon black to be dried to one end of the inner cylinder 21, allow high temperature gas to flow through a high temperature gas channel 23 disposed between the inner cylinder 21 and the outer cylinder 22, and extract dried carbon black from the other end of the inner cylinder 21. The method and the device of drying carbon black are characterized in that combustion gas from a hot air generation furnace 40 and a part of exhaust flowing out of the high temperature gas channel 23 are mixed and supplied to the high temperature gas channel 23 as high temperature gas.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method and apparatus for drying granulated carbon black, and more particularly to a method and apparatus for drying carbon black using combustion gas generated in a hot air generator.

Carbon black is generally manufactured as a granular product depending on its use. As described in Patent Document 1, granular carbon black is produced by granulating with a wet granulator and drying with a drying device. That is, powdery carbon black is supplied from a carbon black feeder to a wet granulator, and mixed and stirred with granulation water separately supplied to the wet granulator. The amounts of supplied carbon black and granulation water are measured by a carbon black flowmeter and a granulation water flowmeter, respectively.

The supplied carbon black is granulated by stirring and rolling in the wet granulator to form carbon black pellets, which are continuously discharged from the pellet outlet of the wet granulator. Since the supply ratio of powdery carbon black and granulation water has a great effect on the properties of the granulated pellets to be produced, it is set by a water/carbon black ratio control device, and based on that, the supply amount of carbon black is supplied. It is controlled by a quantity control device, and the supply quantity of granulation water is also controlled. The granulated pellets discharged from the wet granulator are collected by a carbon black sampling device, and their water content and quality are determined.

For drying the wet carbon black that has been wet-granulated, a dryer using a hot combustion gas from a hot-air generator as a heat source is used (Patent Document 2).

As such a dryer, one having a fixed outer cylinder and a rotary inner cylinder is used. Wet carbon black is supplied to one end of the inner cylinder, and the combustion gas from the hot-air generator is passed between the outer cylinder and the inner cylinder. By rotating the inner cylinder, the wet carbon black rolls from one end side to the other end side, and during this time, it is dried by the heat propagated through the inner cylinder, and the dry carbon black is taken out from the other end side of the inner cylinder. be

Japanese Patent Application Laid-Open No. 2001-115059 JP-A-2004-45116

The drying temperature of carbon black is not always constant, and the required temperature differs depending on the product type, application, and the like. Moreover, even during stable operation, the drying temperature fluctuates depending on the amount of carbon black and the amount of water added.

Patent Literature 2 describes controlling combustion in a hot-air generator in order to control the temperature of hot gas supplied to the dryer.

However, if the combustion control of the hot air generator alone is not enough, the temperature and amount of the high-temperature gas supplied to the dryer can be accurately adjusted according to the conditions of the wet carbon black (supply amount, moisture content, etc.), that is, the set target temperature can be reached without delay. However, it is not easy to control it so that it is maintained within a certain range.

An object of the present invention is to provide a carbon black drying method and apparatus capable of accurately controlling the temperature and amount of hot gas supplied to the dryer.

In addition, conventionally, when the carbon black drying equipment is in operation, the control of the amount of combustion air supplied to the hot air generator is performed based on the experience and intuition of the operator. and the quality of the dried carbon black could fluctuate greatly.

An object of the present invention, in one aspect thereof, is to provide a carbon black drying method and apparatus capable of reducing the workload of the operator and stabilizing the quality of product carbon black.

The gist of the present invention is as follows.

[1] Using a dryer having an inner cylinder and an outer cylinder,
Carbon black in which wet carbon black is supplied to one end of the inner cylinder, high temperature gas is passed through a high temperature gas flow path between the inner cylinder and the outer cylinder, and dry carbon black is taken out from the other end of the inner cylinder. In the drying method of
A carbon black characterized by supplying a mixture of combustion gas from a hot-air generating furnace and a part of waste gas flowing out from the high-temperature gas flow path of the dryer as the high-temperature gas to the high-temperature gas flow path. drying method.

[2] The carbon black drying method of [1], wherein the temperature of the high-temperature gas is controlled by adjusting the amount of the waste gas mixed with the combustion gas.

[3] A change in the amount of the waste gas mixed with the combustion gas (hereinafter referred to as waste gas circulation amount) is corrected by adjusting the flow rate of the combustion gas, and supplied to the high-temperature gas flow path. The carbon black drying method of [2], characterized by controlling the temperature and flow rate of the high temperature gas.

[4] The carbon black drying method of [3], wherein the temperature and flow rate of the hot gas supplied to the hot gas flow path are controlled according to the supply amount of the wet carbon black, or the supply amount and the moisture content. .

[5] When the supply amount of the wet carbon black is increased,
increasing the amount of combustion gas in the hot air generator,
In order to suppress an increase in the temperature of the gas supplied to the high-temperature gas channel, the waste gas circulation rate is increased to control the temperature of the gas supplied to the high-temperature gas channel to a predetermined temperature [4] carbon black drying method.

[6] When the supply amount of the wet carbon black is reduced,
reducing the amount of combustion gas in the hot air generator,
In order to suppress a decrease in the temperature of the gas supplied to the high-temperature gas channel, the amount of waste gas circulated is reduced to stably control the temperature of the gas supplied to the high-temperature gas channel to a predetermined temperature. The carbon black drying method of [4].

[7] a dryer having an inner cylinder, an outer cylinder, and a hot gas flow path between the inner cylinder and the outer cylinder;
A carbon black drying apparatus in which wet carbon black is supplied to one end of the inner cylinder, hot gas is circulated through the hot gas flow path, and dry carbon black is taken out from the other end of the inner cylinder,
A high-temperature gas supply means for supplying a mixture of combustion gas from a hot-air generator and a part of waste gas flowing out from the high-temperature gas flow path of the dryer as the high-temperature gas to the high-temperature gas flow path. A carbon black drying apparatus characterized by:

[8] Waste gas circulation for controlling the temperature of the high-temperature gas supplied to the high-temperature gas flow path by controlling the amount of the waste gas mixed with the combustion gas (hereinafter referred to as waste gas circulation amount) The carbon black drying apparatus according to [7], characterized by comprising an amount control means.

[9] A hot-air generator control means is provided for controlling the flow rate of the high-temperature gas supplied to the high-temperature gas flow path by controlling the amount of combustion gas generated by the hot-air generator [8] carbon black drying equipment.

[10] The waste gas circulation amount control means is characterized in that the temperature of the high-temperature gas supplied to the high-temperature gas flow path is controlled according to the supply amount of the wet carbon black, or the supply amount and the moisture content. 9] carbon black drying device.

[11] When the supply amount of the wet carbon black increases, the waste gas circulation amount control means increases the supply amount of the combustion air and the fuel to the hot air generating furnace to supply the high temperature gas flow path. The carbon black drying apparatus according to [10], wherein the temperature of the gas supplied to the high-temperature gas flow path is controlled to a predetermined temperature by increasing the waste gas circulation amount in order to suppress the temperature rise of the gas.

[12] When the supply amount of the wet carbon black is reduced, the waste gas circulation amount control means reduces the supply amount of the combustion air and the fuel to the hot air generating furnace and supplies them to the high temperature gas flow path. The carbon black drying apparatus according to [10], wherein the temperature of the gas supplied to the high-temperature gas flow path is controlled to a predetermined temperature by reducing the waste gas circulation amount in order to suppress the temperature drop of the gas.

[13] The temperature and flow rate of the high-temperature gas in the high-temperature gas passage are stably controlled by adjusting the waste gas circulation flow rate, and the high-temperature gas flow rate adjusts the flow rate of the fuel gas according to changes in the waste gas circulation flow rate. The carbon black drying apparatus according to [10], wherein the temperature and flow rate of the high temperature gas supplied to the high temperature gas flow path are stably controlled.

In the carbon black drying method and apparatus of the present invention, the combustion gas from the hot air generator and a part of the dryer waste gas (circulating waste gas) are mixed, and the total value is constantly controlled by the flow rate of the combustion gas. , the temperature and flow rate of the hot gas supplied to the dryer can be precisely controlled. For example, even if the operating conditions such as product type and load are changed and each control target value is reset, the operation can be performed so as to meet the new target value.

In one aspect of the present invention, the amount of wet carbon black supplied to the dryer, or the amount of supply and the amount of moisture, is detected, and based on this, the amount of combustion gas generated by the hot-air generator is controlled, thereby supplying to the dryer. By precisely controlling the temperature and flow rate of the high-temperature gas, it is possible to produce pellet-shaped carbon black with stable quality.

It is a lineblock diagram of carbon black drying equipment concerning an embodiment.

Embodiments will be described below with reference to the drawings. As shown in FIG. 1, this carbon black drying equipment includes a granulation supply system 10 for granulating carbon black powder and supplying it to a dryer 20, a dryer 20 for drying the granulated carbon black, a hot air generator 40, A controller 31c is provided for controlling the fuel supply to the burner 41 of the hot-air generating furnace 40 and for controlling the circulation of the dryer waste gas.

The granulation supply system 10 has a feeder 11 for carbon black powder, a granulator 12 for granulating water and carbon black powder, an injection line 13 for a dryer, and the like.

The feeder 11 is provided with a feeder rotational speed control inverter 15b. A carbon black supply line 15 from the feeder 11 to the granulator 12 is provided with a carbon black flow meter 15a. A detection signal from the flow meter 15a is input to the controller 15c, which controls the rotation speed of the feeder rotation speed control inverter 15b, thereby controlling the amount of powdered carbon to the granulator 12.

Water for granulation is supplied to the granulator 12 through a water supply line 17 . The line 17 is provided with a flow meter 17a and a flow control valve 17b. A detection signal from the flow meter 17 a is sent to the valve controller 17 c and the model predictive controller 55 . The opening degree of the valve 17b is controlled by the valve controller 17c, and the amount of water supplied to the granulator 12 is controlled.

The dryer 20 has a coaxial inner cylinder 21 and an outer cylinder 22, a hot gas flow path 23 therebetween, and the like. The outer cylinder 22 is fixed and the inner cylinder 21 is rotatable. The inner cylinder 21 has a slight downward slope from one end side toward the other end side in the direction of the cylinder axis. Granulated carbon black is supplied from the line 13 to one end side of the rotating inner cylinder 21 and rolls toward the other end side. Black is dried. The dried carbon black is taken out from the other end of the inner cylinder 21 .

High-temperature gas is introduced into the high-temperature gas flow path 23 from one end side of the outer cylinder 22 through a pipe 24 . The gas (waste gas) that has flowed through the high-temperature gas flow path 23 and has been lowered in temperature flows out to the pipe 25 from the other end side. The pipe 25 is provided with a pressure gauge 25a and a valve 25b. The opening degree of the valve 25b is controlled by the valve controller 25c so that the pressure detected by the pressure gauge 25a becomes a predetermined pressure.

Pipes 26 and 31 branch from the pipe 25 upstream of the valve 25b. The pipe 26 is for supplying part of the waste gas from the pipe 25 as a purge gas into the inner cylinder 21 . supplied to the other end. The pipe 26 is provided with a flow meter 26a and a valve 26b. The opening degree of the valve 26b is controlled by the valve controller 26c so that the flow rate detected by the flow meter 26a becomes a predetermined flow rate.

The gas inside the inner cylinder 21 flows out through the pipe 29 from the other end side. The pipe 29 is provided with a pressure gauge 29a and a valve 29b. A valve controller 29c controls the valve 29b so that the pressure detected by the pressure gauge 29a becomes a predetermined pressure.

A pipe 31 is for waste gas circulation, and part of the waste gas is supplied to the pipe 24 via the pipe 31 , valve 31 b , blower 32 and pipe 33 . The pipe 24 is provided with a thermometer 24 a downstream of the confluence of the pipe 31 . A detection signal from the thermometer 24a is input to the valve controller 31c, which controls the opening of the valve 31b.

The dryer 20 is provided with a temperature sensor 35 for detecting the temperature of the granular carbon black near the outlet of the inner cylinder 21 . A detection signal from the temperature sensor 35 is sent to the model predictive controller 55 via the controller 36 .

The hot air generator 40 has a burner 41 . Combustion air is introduced into the hot air generator 40 through a pipe 42, a blower 43 and a pipe 44, and the fuel is combusted to generate high temperature combustion gas. The pipe 42 is provided with a flow meter 42a and a valve 42b. The opening degree of the valve 42b is controlled by the valve controller 42c so that the flow rate detected by the flowmeter 42a becomes a predetermined flow rate.

Fuel oil or fuel gas is supplied to the burner 41 through pipes 46 , 47 , 48 . Flowmeters 46a, 47a, 48a and valves 46b, 47b, 48b are provided in the pipes 46, 47, 48, respectively. controlled by devices 46c, 47c and 48c. The flow rates detected by the flowmeters 46a to 48a and control signals from the combustion control system 51 are input to the valve controllers 46c to 48c. The combustion control system 51 receives a set air ratio from an air ratio setter 52, a total gas flow set value from a total gas flow controller 53, and an air flow rate detection signal from a flow meter 42a. A detection signal of the flow rate of each flowmeter 46a, 47a, 48a is input. The total gas flow rate controller 53 receives the total flow rate of 33 a and 42 a and the target flow rate from the model predictive controller 55 .

Next, the mode of control of this carbon black drying facility will be described.

[First aspect]
In the first mode, the amount of waste gas circulated is controlled by controlling the opening of the valve 31b, and the temperature of the high-temperature gas flowing through the flow path 23 is kept constant. The amount of high-temperature gas flowing through the flow path 23 is controlled by adjusting the flow rate with the increase/decrease corrected.

As described above, the drying temperature of carbon black is not always constant, and the required temperature varies depending on the product type, application, and the like. Moreover, even during stable operation, the drying temperature fluctuates depending on the amount of carbon black and the amount of water added. According to this aspect, by controlling the combustion gas flow rate, the set target temperature can be reached without delay, and the amount and temperature of the hot gas supplied to the dryer can be accurately controlled so as to be maintained within a certain range. Even if the operating conditions such as product type and load are changed and each control target value is reset, the operation can be performed so as to match the new target value.

[Second aspect]
The second aspect aims to reduce the workload of operators, improve the accuracy of operation, and improve the stability of product temperature.

In the second mode, the temperature and flow rate of the high-temperature gas supplied from the pipe 24 are controlled so that the temperature of the dry carbon black detected by the temperature sensor 35 becomes the target temperature. In a second embodiment, a model predictive controller 55 is used to set the hot gas target flow rate.

If the feed of wet carbon black to the dryer 20 increases, the model predictive controller 55 predicts that the temperature 13 sensed by the sensor 35 will decrease with a time delay. Therefore, the model prediction controller 55 outputs a prediction value for the increase to the total gas flow rate controller 53 . Based on the output signal from the controller 53, the control system 51 increases the opening of the valve 42b, increases the combustion air flow rate, and increases the fuel supply amount. As a result, the amount of combustion gas generated and the temperature of the hot-air generator 40 increase and rise, and the gas temperature detected by the sensor 24a rises above the temperature (steady temperature) up to that point. The controller 31c increases the degree of opening of the valve 31b to increase the amount of waste gas circulated, thereby stably controlling the temperature detected by the sensor 24a to a predetermined temperature, for example, the original steady temperature.

In this way, when the amount of carbon black feed to the dryer 20 increases, the high-temperature gas flow rate flowing through the flow path 23 is quickly controlled to the target set value (increasing direction) of the total gas flow rate controller 53, and the The gas temperature 24a can be controlled to properly dry the wet carbon black.

If the feed rate of wet carbon black to the dryer 20 decreases, the model predictive controller 55 predicts that the temperature sensed by the sensor 35 will increase. Therefore, the model prediction controller 55 outputs the prediction value of the reduction to the total gas flow rate controller 53 . Based on the output signal of controller 53, control system 51 reduces fuel and adjusts valve 42 based on the air ratio to reduce combustion air flow. As a result, the amount of combustion gas produced by the hot-air generator 40 is reduced, and the temperature detected by the sensor 24a is lower than the temperature (steady temperature) up to that point. Therefore, the controller 31c reduces the degree of opening of the valve 31b to reduce the waste gas circulation amount, and stably controls the temperature detected by the sensor 24a to a predetermined temperature, for example, the original steady temperature.

In this way, when the amount of carbon black fed to the dryer 20 is reduced, the flow rate of the high-temperature gas flowing through the flow path 23 is rapidly reduced, and the gas temperature is controlled to be constant, thereby properly drying the carbon black. can be done.

Even in the second mode, the flow rate of the high-temperature gas flowing into the flow path 23 from the pipe 24 cannot be actually measured. is controlled as the amount of hot gas introduced into flow path 23 . Further, the amount of waste gas circulated is controlled by controlling the opening degree of the valve 31b by the controller 31c. These control the temperature of the high-temperature gas introduced into the flow path 23 . The target flow rate and temperature of the high-temperature gas can be stably controlled by alternately interfering with each other.

In the second mode, the target value of the detection temperature of the sensor 35 is set in the total gas amount controller 53 by setting the hot gas amount predicted by the model predictive controller 55 based on the wet carbon black feed amount. Wet carbon black can be dried under suitable conditions that allow for lag.

In addition, in this second aspect, the control system 51 performs control by the double cross limit. As is well known, in the double cross limit control system, when the required combustion load amount suddenly changes, the control loops for both the fuel flow rate and the air flow rate apply upper and lower limits to the target values of their own loops according to the control amount of the other party. Control is performed to follow the required amount of combustion to suppress combustion incompatibility and to save energy.

10 granulation supply system 11 feeder 12 granulator 20 dryer 40 hot air generator 51 combustion control system 52 air ratio setter 53 total gas flow controller 55 model predictive controller

Claims (13)

Using a dryer having an inner cylinder and an outer cylinder,
Wet carbon black is supplied to one end of the inner cylinder, high temperature gas is passed through a high temperature gas flow path between the inner cylinder and the outer cylinder, and dry carbon black is taken out from the other end of the inner cylinder. In the drying method of
A carbon black characterized by supplying a mixture of combustion gas from a hot-air generating furnace and a part of waste gas flowing out of the high-temperature gas flow path of the dryer as the high-temperature gas to the high-temperature gas flow path. drying method. 2. The carbon black drying method according to claim 1, wherein the temperature of said high-temperature gas is controlled by adjusting the amount of said waste gas mixed with said combustion gas. A change in the amount of the waste gas mixed with the combustion gas (hereinafter referred to as waste gas circulation amount) is corrected by adjusting the combustion gas flow rate, and the amount of high temperature gas supplied to the high temperature gas flow path is corrected. 3. The method of drying carbon black according to claim 2, wherein temperature and flow rate are controlled. 4. The method of drying carbon black according to claim 3, wherein the temperature and flow rate of the hot gas supplied to the hot gas passage are controlled according to the supply amount of the wet carbon black, or the supply amount and the moisture content. When the supply amount of the wet carbon black is increased,
increasing the amount of combustion gas in the hot air generator,
In order to suppress an increase in the temperature of the gas supplied to the high-temperature gas passage, the amount of waste gas circulated is increased to control the temperature of the gas supplied to the high-temperature gas passage to a predetermined temperature. carbon black drying method. When the supply amount of the wet carbon black is reduced,
reducing the amount of combustion gas in the hot air generator,
4. In order to suppress a decrease in the temperature of the gas supplied to the high temperature gas flow path, the amount of waste gas circulated is reduced to control the temperature of the gas supplied to the high temperature gas flow path to a predetermined temperature. carbon black drying method. a dryer comprising an inner cylinder, an outer cylinder, and a hot gas flow path between the inner cylinder and the outer cylinder;
A carbon black drying apparatus in which wet carbon black is supplied to one end side of the inner cylinder, hot gas is circulated through the hot gas flow path, and dry carbon black is taken out from the other end side of the inner cylinder,
A high-temperature gas supply means for supplying a mixture of combustion gas from a hot-air generator and part of waste gas flowing out of the high-temperature gas flow path of the dryer as the high-temperature gas to the high-temperature gas flow path. A carbon black drying apparatus characterized by: waste gas circulation amount control means for controlling the temperature of the high-temperature gas supplied to the high-temperature gas passage by controlling the amount of the waste gas mixed with the combustion gas (hereinafter referred to as waste gas circulation amount); The carbon black drying apparatus of claim 7, comprising: The carbon black according to claim 8, further comprising a hot-air generator control means for controlling the flow rate of the high-temperature gas supplied to the high-temperature gas flow path by controlling the amount of combustion gas generated in the hot-air generator. drying equipment. 10. The method of claim 9, wherein the waste gas circulation amount control means controls the temperature of the high-temperature gas supplied to the high-temperature gas passage according to the supply amount of the wet carbon black, or the supply amount and the moisture content. Carbon black drying equipment. When the supply amount of the wet carbon black increases, the waste gas circulation amount control means increases the amount of combustion air and fuel supplied to the hot air generating furnace to reduce the amount of gas supplied to the high-temperature gas flow path. 11. The carbon black drying apparatus according to claim 10, wherein the temperature of the gas supplied to the high-temperature gas passage is controlled to a predetermined temperature by increasing the waste gas circulation amount in order to suppress the temperature rise. When the supply amount of the wet carbon black is reduced, the waste gas circulation amount control means reduces the amount of combustion air and fuel supplied to the hot air generating furnace to reduce the amount of gas supplied to the high temperature gas flow path. 11. The carbon black drying apparatus according to claim 10, wherein the temperature of the gas supplied to the high-temperature gas flow path is controlled to a predetermined temperature by reducing the waste gas circulation amount in order to suppress the temperature drop. The temperature and flow rate of the hot gas in the hot gas passage are stably controlled by adjusting the waste gas circulation flow rate, and the hot gas flow rate is controlled by adjusting the flow rate of the fuel gas according to changes in the waste gas circulation flow rate. 11. The carbon black drying apparatus according to claim 10, wherein the temperature and flow rate of the hot gas supplied to the hot gas flow path are stably controlled by correcting.

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