JPH08283740A - Method for controlling preheating of coke oven coal - Google Patents

Abstract

PURPOSE: To heighten the precision of preheating temp. control by directly measuring the temp. of preheated coal with a thermometer placed in a coal reservoir and regulating the temp. of the preheated coal to a set value by increasing or reducing the temp. or amount of a preheating gas to be fed to a coal-preheating tower. CONSTITUTION: Coal Cc is introduced from a storage hopper 3 into a lower part of a first preheating tower 1, and ascends therein while being firstly preheated with a preheating gas. The preheated coal Cc is separated from the gas in a cyclone 5 and fed to a second preheating tower 8. A preheating gas heated to about 300-600 deg.C is introduced from a preheating gas generator furnace 11 into the tower 8 to secondly preheat the coal Cc. This preheated coal Ch is separated from the preheating gas and sent to a coke oven. A coal reservoir 17 is disposed beneath a cyclone 9 of the tower 8, and a thermometer 18 is placed inside the reservoir 17. The temp. of the coal Ch passing through the reservoir 17 is directly measured and the data obtained are inputted to a computing unit 19, which compares the data with a set preheating temp. and calculates the temp. and amount of a preheating gas necessary for attaining the set preheating temp. to control the amount of a fuel gas to be fed to the furnace 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preheating control method for preheating coal for a coke oven by an air flow type heating device.

[0002]

2. Description of the Related Art In recent years, in the operation of a coke oven, from the viewpoint of shortening the time of the coke operation and improving the thermal efficiency, prior to charging coal into the coke oven, for example, Japanese Patent Publication No. 60-3.
As disclosed in Japanese Patent No. 9315, coal is preheated by using a gas stream type heating device that uses a coke oven exhaust gas and a combustion exhaust gas.

In order to ensure the quality of coke while ensuring high productivity in the entire coke operation, it is necessary to ensure that the functions of coal preheating operation and coke oven operation are divided according to the characteristics (property) of coal. What is done is important. For this reason, it is essential to control the preheating temperature in the preheating operation of coal.

In the conventional management of the coal preheating temperature, for example, the gas temperature from the coal preheating tower is measured, and the gas temperature is adjusted so that the temperature of the coal becomes the temperature at the set temperature. A method of increasing or decreasing the amount of preheating gas supplied into the preheating tower is adopted.

However, this method leaves many problems to be solved. First, the background will be described. Co-
Coal for the coke oven is usually charged by blending 4 to 10 kinds of brands. This is to minimize fluctuations in the quality of the product coke and to combine the characteristics of each type of coal to achieve better and more stable characteristics than the quality obtained from a single brand. This is done to compensate for many disturbance factors such as variations, instability, and ship navigation.

Coal has many variations in characteristics depending on the brand, and industrially, the volatile content indicating the degree of carbonization, and the fluidity and expandability indicating caking are important characteristics. Also,
Coal has a characteristic that its shape changes with an increase in temperature, and in a normal case, 300 ° C or higher is a temperature range in which the shape change can occur. Therefore, in the preheating operation of coal, sensitively detecting the change in physical properties is an important factor for utilizing the physical properties of coal.

On the other hand, in coke oven operation, coal coal
As mentioned above, in order to improve the efficiency of coke production and make it easier to improve the quality, the temperature immediately before the softening and melting of the coal is 350 ° C.
It is effective to raise the temperature from 1 to 450 ° C.

Against this background, as in the conventional example,
In the case of adjusting the amount of heating gas in the preheating system, for example, based on the gas temperature in the coal preheating tower, there is a certain correlation between the gas temperature in the coal preheating tower and the temperature of the product coal, which is appropriate. The accuracy of can be adjusted. However, this correlation varies greatly depending on the amount of coal treated, the amount of water adhering to the coal, the target coal temperature, the coal particle size, etc., so the coal softens unexpectedly depending on the operating conditions,
The preheating temperature rise was insufficient, which sometimes adversely affected the quality of coke.

[0009]

DISCLOSURE OF THE INVENTION The present invention, in a coal preheating method using an air flow type heating device, is greatly affected by fluctuations in the amount of coal treated, the amount of water adhering to coal, the target coal temperature and the like as in the above-mentioned conventional example. The present invention provides a coal preheating control method provided with a means capable of adjusting the preheating temperature of coal in a stable manner and with high accuracy.

[0010]

The first invention of the present invention is as follows:
In a coal preheating method using a gas stream type heating device, a coal pool is configured in the lower part of a preheating coal collecting device provided at an outlet of a coal preheating tower, and a thermometer is inserted into the coal pool, and the coal pool is stored. The preheating of the coal for the coke oven characterized by directly measuring the temperature of the preheated coal accumulated in the coke oven and increasing or decreasing the temperature of the preheating gas or the amount of preheating gas supplied to the preheating tower so that the coal reaches the set preheating temperature. Control method.

A second aspect of the present invention is a coal preheating method using a gas stream type heating device, wherein a suction sampling pipe for sampling is inserted near the top of the coal preheating tower, and the sampling pipe is provided at the outlet of the coal preheating tower. Connected to the outlet gas duct of the preheated coal collecting device, sucking the preheated coal to the sampling device through the suction sampling pipe, measuring the temperature of the sucked preheated coal,
A preheating control method for coke coal, comprising increasing or decreasing the temperature or the amount of preheating gas supplied to a coal preheating tower so that the preheating coal has a set preheating temperature.

A third aspect of the present invention is a coal preheating method using a gas stream type heating device, in which a gas analyzer is provided in the exit side gas duct of a coal preheating tower, and one of the gas components in the gas generated during preheating is selected. Or to detect the concentration of multiple types of gas, and to increase or decrease the temperature or amount of preheating gas supplied to the coal preheating tower so that this gas concentration is the gas concentration at which the preheating coal is at the set preheating temperature. It is a characteristic preheating control method for coke oven coal.

[0013]

In the present invention, the temperature of the preheated coal is directly measured, or the concentration of a specific gas component in the preheated exhaust gas is measured to estimate the temperature of the coal. Since the amount is adjusted, the preheat temperature control accuracy can be improved and the coke operation can be stabilized at a high level without being affected by fluctuations in the amount of coal processed, the amount of water adhering to coal, the target coal temperature, the coal particle size, etc. , Improve the quality and productivity of coke, and reduce the manufacturing cost.

As is well known, when coal arrives at a coke oven, it usually contains or adsorbs about 7% to 10% of water. When this coal is subjected to carbonization in a coke oven to form a coke, this water delays the carbonization rate, so that the packing density (hereinafter referred to as bulk density) during charging into the coke oven carbonization chamber is reduced. In addition to lowering, it has a disadvantageous effect of increasing the amount of heat required for carbonization. Therefore, it is industrially preferable to dry until the water content becomes zero before charging it into the coke oven, and to heat the coal to the last minute in order to improve productivity and coking property. Be advantageous.

The inventors of the present invention pay attention to the fact that the properties of coal change when it is heated, preheat the temperature to as high a temperature as possible, and do not cause handling trouble such as stickiness due to softening of the coal. The present invention was conceived to make it possible to raise the temperature to a temperature at which it does not deteriorate, and in order to realize it, various studies were conducted to improve and stabilize the preheating temperature control accuracy, and the present invention was reached.

The present invention will be described below with reference to the drawings. First, 2 using the air flow type heating device to which the present invention is applied
The basic structure of the tower-type coal preheating facility will be outlined with reference to FIG. In FIG. 1, reference numeral 1 denotes a first preheating tower (drying tower), a coal storage hopper 3 is disposed below the first preheating tower (drying tower) via a rotary feeder 2, and a preheating gas introduction pipe 4 is connected thereto. Further, a cyclone 5 is arranged in the upper part, the upper part of the cyclone is connected to the exhaust gas pipe 6, and the lower part is connected to the lower part of the second preheating tower (preheating tower) 8 via the rotary feeder 7. .

A cyclone (preheated coal collecting device) 9 is disposed above the second preheating tower 8. The upper portion of this cyclone is connected to the lower portion of the first preheating tower 1 and the lower portion of the preheater is preheated. A coal discharging device 10 is provided.

Reference numeral 11 denotes a preheating gas generating furnace, which is connected to a lower portion of the second preheating tower 8 via a preheating gas supply pipe 12. A blower 13 sucks the exhaust gas from the cyclone 5 of the first preheating tower 1 and sends it to the dust collector 14. Reference numeral 15 denotes a diffusion tower that diffuses the exhaust gas collected by the dust collector 14.

In the operation of the coal preheating facility using the air-flow type heating device constructed as described above, the coal Cc is fed from the storage hopper 3 into the first preheating tower 1 by the rotary feeder 2. In the lower portion of the first preheating tower 1, the preheating gas supplied from the preheating gas generation furnace 11 to the lower portion of the second preheating tower 8 and passed through the second preheating tower is fed from the upper portion of the cyclone 9 to the preheating gas introduction pipe 4 The coal Cc, which has been blown in through the first preheating tower 1, is first preheated (dried) by the preheating gas, rises in the first preheating tower 1, and is collected by the cyclone 5. The coal collected here is charged into the lower part of the second preheating tower 8 by the rotary feeder 7. The temperature of the coal Cc at this time is 60 to 300 ° C. The exhaust gas containing a large amount of water vapor from the cyclone 5,
It is introduced into the dust collector 14 through the exhaust gas duct 6 and the blower 13, and is diffused from the diffusion tower 15 after dust collection.

A preheated gas of 300 to 600 ° C. is blown into the lower portion of the second preheating tower 8 from the preheated gas generation furnace 11, and the coal Cc which is first preheated (dried) in the first preheating tower 1 is preheated gas. At the same time, it rises while being secondarily preheated in the second preheating tower 8, and is collected by the cyclone 9 as preheated coal Ch. The temperature at this time is 150 to 450 ° C. Here, the collected preheated coal Ch is loaded into a coke oven (not shown).

The present invention is applied to a case where the present invention is applied to a coal preheating facility equipped with a first preheating tower (drying tower) and a second preheating tower (preheating tower) using the airflow type heating device constructed as described above. An example of an apparatus that implements

(First Invention) In the first invention of the present invention, in the lower part of the cyclone (preheated carbon collecting device) 9 of the second preheating tower 8 in FIG. 1, as shown in FIG. A ball valve 16 for cutting out coal is provided, and a coal reservoir 17 is formed on the upper portion thereof, and a thermometer 18 is inserted and arranged therein, and the temperature of the preheated coal Ch accumulated in the coal reservoir 17 is directly measured.

This measurement information is input to the calculator 19 to be compared with a preset preheating temperature, and the temperature and amount of preheating gas for changing the measured temperature to the preset preheating temperature are calculated to preheat. The amount of fuel gas and the amount of auxiliary gas supplied to the gas generation furnace 11 are controlled. The relationship between the control amount and the change amount of the coal preheating temperature can be obtained in advance based on actual results, calculations, and the like. An example of this control flow is shown in FIG.
The concept is shown in.

(Second Invention) In the second invention of the present invention, in the upper part of the second preheating tower 8 in FIG. 1, as shown in FIG. 4, the downward flow is made to the flow path of the mixed flow of preheated coal and gas. Suction sampling tube 2 for sampling preheated coal having a suction port 20 of
1 is provided. The suction collection tube 21 has a cyclone 2
2 is connected, and the upper portion of this cyclone is connected to the preheating gas introduction pipe 4 from the cyclone 9 on the second preheating tower 8 side to the first preheating tower 1.
And the preheated coal Ch is sucked from the upper part of the second preheat tower 8 by the action of this preheated gas flow and collected by the cyclone 22.

A ball valve 23 for cutting out preheated coal sampled and collected is provided below the cyclone 22, and a coal reservoir 24 is formed above the ball valve 23.
The thermometer 24 is inserted and arranged, and the temperature of the preheated coal Ch accumulated in the coal reservoir 24 is directly measured.

This measurement information is input to the calculator 19 and compared with a preset set preheating temperature, and the temperature of the preheated gas and the amount of preheated gas for making the set preheated temperature from this measured temperature are calculated and the preheated temperature is calculated. The amount of fuel gas and the amount of auxiliary gas supplied to the gas generation furnace 11 are controlled.

The relationship between the control amount and the change amount of the coal preheating temperature can be obtained and set in advance based on actual results, calculation and the like. This control flow is the same as in the case of the first invention shown in FIG.

(Third Invention) In the third invention, in the outlet duct (preheated gas introduction pipe 4) near the cyclone (preheated coal collecting device) 9 on the second preheating tower 8 side in FIG. , A gas sampling pipe 26 is provided, a gas analyzer 27 is connected to this gas sampling pipe, and the analysis information from this gas analyzer is input to a calculator 28 for comparison with a preset gas concentration. At the same time, the temperature of the preheating gas and the preheating gas amount for changing the gas concentration to the set gas concentration are calculated, and the fuel gas amount and the auxiliary combustion gas supply amount to the preheating gas generation furnace 11 are controlled.

Coal begins to soften as the temperature rises, and at the same time produces coal gas and tar. In an air-flow type rapid coal heating machine, coal reacts in the presence of excess air, which causes deterioration of coal quality and causes a coal dust explosion.
Management of fuel gas properties and proper amount of combustion air are important management items.

The gas circulating in the system during preheating of coal is
Nitrogen gas, carbon dioxide, and water vapor are the main components, but the concentration of gas in these gases may be mixed with the gas generated by the thermal decomposition of coal or tar depending on the heating stage of coal. Therefore, by monitoring the concentration of the gas component discharged from the second preheating tower 8, the temperature of coal can be grasped.

The coal gas component, as described above, is usually
Carbon monoxide, hydrogen, methane, ethane, propane, and nitrogen are the main components, but from the start of generation until the temperature rises for a while, there are many heavy hydrocarbon components such as methane, ethane, and propane.
It is desirable to control the concentrations of these gas components. That is, since the preheating of coal is performed up to the temperature immediately before the softening of the coal, for example, when the concentration of CH ₄ (methane) gas generated after the softening is detected, the coal is preheated to the softening temperature of the coal and melting starts. It means that stickiness or the like is generated, and further high temperature preheating means that coal properties are impaired.

Therefore, the gas to be analyzed here is CH ₄ which begins to be generated in the temperature range of 370 to 430 ° C.
And by measuring the concentrations of these gases,
The form of the coal can be determined, and the temperature of the preheated coal can be grasped from this form.

[0033] FIG. 7 shows the relationship between the temperature of the CH ₄ and preheating the coal in the gas, for example, if the 0.1% to 1.0% region the concentration of CH ₄ in the gas, preheating the coal Temperature is 37
It shows that it is in a suitable range of 0 to 430 ° C.

Therefore, the fuel gas amount and the auxiliary combustion gas supply amount to the preheating gas generation furnace 11 are controlled so that these gas concentrations are maintained within this range. The relationship between these controlled variables and the gas concentration of CH _{4 in} the above gas can be obtained in advance based on actual results, calculations and the like. An example of this control flow is conceptually shown in FIG.

[0035]

【Example】

(Example 1) In a coal preheating facility configured as shown in FIGS. 1, 2, and 3, the first invention of the present invention is applied to contain an average water content of 7% and a volatile content of 27%. Caking coal with an average particle size of 0.6 mm is preheated, and the amount of preheat treatment is 100 t /
Preheat operation was carried out in hr. During this period, during operation, the temperature of the preheated coal Ch in the coal reservoir 17 at the lower part of the cyclone on the second preheater side 8 is actually measured, so that the temperature of the preheated coal falls within the range of 390 to 410 ° C. The preheating gas temperature and the amount of preheating gas for the first and second preheating towers 8 were adjusted.

With respect to the preheated coal Ch that has been preheated in this way and discharged from the cyclone 9 on the second preheating tower 8 side,
When the temperature was measured, it was within the range of 395 to 410 ° C, and when the properties of this preheated coal were examined,
The volatile content was 26.8%, the water content was 0%, the coking property was not deteriorated, and the rupture strength was stable at a high level of 84.3 against the target value of 84.5.

(Embodiment 2) In a coal preheating facility constructed as shown in FIGS. 1 and 4, the second invention of the present invention is applied to contain an average water content of 7% and a volatile content of 27%. Caking coal with an average particle size of 0.6 mm is preheated, and the amount of preheat treatment is 90
Preheat operation was carried out at t / hr. During this period, the temperature of the preheated coal Ch sampled from the suction sampling pipe 21 arranged in the upper part of the second preheat tower 8 during operation is measured, so that the temperature of the preheated coal is in the range of 390 to 410 ° C. The preheating gas temperature and the amount of preheating gas for the first preheating tower 1 and the second preheating tower 8 were adjusted.

The temperature of the preheated coal thus preheated and discharged from the cyclone on the second preheating tower side was measured and found to be within the range of 400 to 410 ° C. As a result of investigation, the volatile content was 26.7% and the water content was 0, which was almost the same as in Example 1.
%, The coking property hardly decreased as predicted in advance, and the rupture strength was stable at a high level of 84.2 with respect to the target value of 84.5.

(Embodiment 3) In a coal preheating facility constructed as shown in FIGS. 1, 5 and 6, the third invention of the present invention is applied to obtain an average water content of 7% and a volatile content of 29%. % Caking coal having an average particle size of 0.5 mm was preheated, and preheat operation was performed at a preheat treatment amount of 100 t / hr. During this period, during operation, the gas is sampled from a gas sampling tube arranged in the gas tube from the cyclone on the second preheating tower side, and the CH ₄ gas concentration in this gas is measured to determine that the CH ₄ gas concentration is the preheated coal. Temperature is 38
The preheating gas temperature and the amount of preheating gas for the first preheating tower 1 and the second preheating tower 8 were adjusted so that the concentration range corresponded to 0 to 400 ° C.

The temperature of the preheated coal thus preheated and discharged from the cyclone on the second preheating tower side was measured and found to be within the range of 390 to 400 ° C. As a result of examination, the volatile content was reduced by about 0.2% as in the case of Example 1, and
The moisture content was 8.8%, the moisture content was 0%, the coking property was not deteriorated, and the rupture strength was stable at a high level almost in the same manner as in Examples 1 and 2.

On the other hand, as in the conventional example, the temperature of the outlet (top) of the second preheating tower 8 is measured, and the first preheating is carried out so that the temperature of the preheated coal falls within the range of 380 to 400 ° C. Tower 1
And the preheating gas temperature and the amount of preheating gas for the second preheating tower 8 were adjusted.

The preheated coal Cc preheated in this manner and discharged from the cyclone 9 on the second preheating tower 8 side is
When the temperature was measured, when the temperature was outside the range of 380 to 400 ° C on the low temperature side or when the supplied coal was finer than 0.1 mm, there was not a few that was off on the high temperature side, and the properties of this preheated coal were investigated. , There was a trace of melting on the surface. In the case of molten coal, the volatile content is reduced to 26%, the fluidity and expandability of the coal are also reduced, and the crush strength is 81.5 to 79, which is low and unstable with respect to the target value of 84.5. It was enough.

The present invention is not limited to the above-mentioned embodiment, and for example, the preheated coal sampling position,
Regarding the number of points, the gas sampling position, the number of points, the control mechanism, etc., depending on the coal conditions to be preheated, the structure of the coal preheating facility, the operating conditions, etc., within the range satisfying claims 1 to 3, It is changed, and it is also possible to combine claim 1 and claim 3 or claim 2 and claim 3 to control by information with high sensitivity.

[0044]

INDUSTRIAL APPLICABILITY In the present invention, the temperature of the preheated coal is directly measured, or the temperature of the preheated gas is estimated by measuring the concentration of a specific gas component in the preheated exhaust gas to estimate the temperature of the coal, Since the amount of preheated gas is adjusted, it is not affected by fluctuations in the amount of coal treated, the amount of water adhering to coal, the target coal temperature, etc., the preheat temperature management accuracy can be improved, and the coke operation can be stabilized at a high level. The quality and productivity of coke can be improved and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side explanatory view showing an equipment arrangement example in an example of an air flow heating type coal preheating equipment for carrying out the present invention.

FIG. 2 is a partial cross-sectional side view showing a main part of an example of equipment arrangement in the embodiment of the present invention.

FIG. 3 is a flow explanatory diagram of a control example in the embodiment of FIG.

FIG. 4 is a partial cross-sectional side view showing a main part of an example of equipment arrangement in another embodiment of the present invention.

FIG. 5 is a partial cross-sectional side view showing a main part of an example of equipment arrangement in another embodiment of the present invention.

6 is an explanatory flow diagram of a control example in the embodiment of FIG.

FIG. 7 is an explanatory diagram showing a relationship between a coal heating temperature and a generated CH ₄ gas concentration.

[Explanation of symbols]

 1 First preheating tower (drying tower) 2 Rotary feeder 3 Storage hopper 4 Preheating gas introduction pipe 5 Cyclone 6 Exhaust gas duct 7 Rotary feeder 8 Second preheating tower (preheating tower) 9 Cyclone (preheating coal trap) 10 Discharge device ( Rotary valve) 11 Preheated gas generation furnace 12 Preheated gas supply pipe 13 Blower 14 Dust collector 15 Dispersion tower 16 Ball valve 17 Coal trap 18 Thermometer 19 Operator 20 Collection port 21 Suction collection tube 22 Cyclone (for sampling device) 23 Ball valve 24 Coal reservoir 25 Thermometer 26 Gas sampling pipe 27 Gas analyzer 28 Operator Cc coal Ch Preheated coal

Claims (3)

[Claims] 1. A coal preheating method using a gas stream type heating device, wherein a coal reservoir is formed below a preheated coal collecting device provided at an outlet of a coal preheating tower, and a thermometer is inserted into the coal reservoir. Every time, the temperature of the preheated coal accumulated in the coal reservoir is directly measured, and the temperature or amount of the preheat gas supplied to the coal preheating tower is increased or decreased so that the coal reaches the set preheat temperature. Preheating control method for coal for coke oven. 2. A coal preheating method using a gas stream type heating device, wherein a suction sampling pipe for sampling is inserted near the top of the coal preheating tower, and the sampling pipe is provided at the exit of the coal preheating tower. Connect to the outlet gas duct of the collector,
The preheated coal is sucked into the sampling device via the suction sampling pipe, the temperature of the sucked preheated coal is measured, and the temperature or preheat of the preheated gas supplied to the coal preheating tower is adjusted so that the preheated coal reaches the set preheated temperature. A preheating control method for coke coal, characterized by increasing or decreasing the amount of gas. 3. A coal preheating method using a gas stream type heating device, wherein a gas analyzer is provided in the exit side gas duct of the coal preheating tower, and one or more kinds of gas components in the gas generated during preheating are selected. A coke characterized by detecting the concentration of gas, and increasing or decreasing the temperature or the amount of preheating gas supplied to the coal preheating tower so that the preheating coal has a gas concentration at the set preheating temperature. Preheating control method for coal for furnace.