JP6724738B2 - Judging completion method for coke oven - Google Patents

Description

The present invention relates to a method for determining completion of dry distillation of coke in a chamber-type coke oven.

In a coke oven of a chamber furnace that produces carbon by dry-distilling coal, the coal is sequentially charged into a plurality of carbonization chambers, the dry-distillation reaction is performed at a high temperature of around 1100° C., and when the dry-distillation reaction ends, the coke produced It is operated by discharging (kiln) from the carbonization chamber with an extruder. At that time, in order to produce high-quality coke, for example, high-strength coke, and to efficiently operate the coke oven, it is accurately determined whether the carbonization of coal is completed before the kiln is taken out. There is a need to. The completion of the carbonization of coal is also referred to as "firefall".

Conventionally, the completion of carbonization is determined by an expert called "Himi" who opens the top cover provided on the upper part of the rising pipe connected to the carbonization chamber, ignites the gas emitted from it and ignites it. It was done by judging the color of the flame. However, in this method, it is necessary for the expert to make a judgment frequently for each dozen or more carbonization chambers and for each timing of completion of carbonization, and the workload is high, so the expert opens the top cover. There has been a demand for a method for determining the completion of carbonization that does not require the work to be performed.

Therefore, a dry distillation completion determination method that does not require a skilled person has been conventionally proposed, and the proposed dry distillation completion determination method is mainly a method in which the temperature of the generated gas is used as an index.

For example, in Patent Document 1, a relational expression “Y=a×Tmax+b(a) between a maximum temperature Tmax of a gas generated during carbonization and a gas temperature Y at the time of a fire fall (dry carbonization completion) detected and detected by a fire watch , b is the constant determined by the structure of the coke oven) "obtained in advance, sequentially measuring the temperature change of the gas generated during dry distillation, detects the maximum temperature Tmax _1, the maximum temperature Tmax ₁ By substituting into the above relational expression to calculate the burn-down temperature Y ₁ , continuously measuring the temperature of the generated gas, and determining the time when the measured gas temperature matches the burn-down temperature Y ₁ as the time of the burn-down. Is proposed.

Further, in Patent Document 2, the temperature of the gas generated during carbonization is measured, and the determination burn time T and the elapsed time X ₁ from the time of coal charging at the time when the generated gas temperature reaches the maximum, temperature drop gradient _{X 2,} coal moisture _{X 3,} relationship between the charging amount _{X 4} coal _{"T = a 1 × X 1 +} a 2 × X 2 + a 3 × X 3 + a 4 × X 4 + b 1 (a ₁ to ₄ , b ₁ are constants determined by the structure of each coke oven)”, and a method of determining the fire fall time is proposed.

However, the fact that the generated gas temperature shows the maximum temperature (peak temperature) is caused by the increase in the amount of coal carbonized during the carbonization in a healthy carbonization chamber (kiln), which causes the coke oven to deteriorate. In the carbonization chamber where uniform dry distillation is impossible because of this, the amount of coal to be dry distilled does not increase at the end of the dry distillation, and the peak of the generated gas temperature at the end of the dry distillation is less likely to appear. At present, there are many cases where the peak of the generated gas temperature is difficult to appear at the final stage of carbonization due to the deterioration of the coke oven.

The dry distillation completion determination method using the maximum temperature of the generated gas as an index, which is proposed in Patent Document 1 and Patent Document 2, cannot be applied in a carbonization chamber where the peak of the generated gas temperature is less likely to appear, and other dry distillation is performed. It is necessary to use the completion judgment method.

On the other hand, as a dry distillation completion determination method that does not use the generated gas temperature, a dry distillation completion determination method that uses the composition of the evolved gas (for example, see Patent Document 3) has been proposed, but an analyzer is installed in each of a large number of carbonization chambers. Since it is necessary to install the analyzer, the installation cost of the analyzer increases, which is not practical.

Japanese Patent Publication No. 46-6497 Japanese Patent Publication No. 59-50196 JP 61-266489 A

The present invention has been made in view of the above circumstances, and an object thereof is to dry-coke coke in a chamber furnace type coke oven, even when the peak of the generated gas temperature does not appear in the final stage of the carbonization, the generated gas is An object of the present invention is to provide a dry distillation completion determination method capable of accurately determining completion of dry distillation using temperature as an index.

The gist of the present invention for solving the above problems is as follows.
[1] In a carbonization chamber of a coke oven having a plurality of carbonization chambers, the temperature of the gas generated during the carbonization reaction of coal in each of the carbonization chambers is measured at predetermined time intervals t _it to determine the previous gas temperature. The measured value and the current gas temperature measured value are compared, and the first time point at which the current gas temperature measured value is lower than the immediately preceding gas temperature measured value by the predetermined temperature difference Tcr or more is set as the reference time t _0, and the reference time t ₀ is set. There is a case where the temperature difference between the immediately preceding gas temperature measurement value and the current gas temperature measurement value is continuously obtained, with the time t ₀ as the start time, and the temperature difference becomes equal to or more than the predetermined temperature difference Tcr. The time until the predetermined number of times N is reached is time t _1, and the time t ₂ obtained by adding the time t ₁ to the reference time t ₀ is determined as the dry distillation completion time, which is the dry distillation in the coke oven. Completion judgment method.
[2] The predetermined temperature difference Tcr is based on an average gas temperature Tav which is an average value of gas temperatures measured in a period from a predetermined time t ₃ to a predetermined time t ₄ from the start of charging of the coke oven. The method of determining the completion of carbonization in the coke oven according to [1] above, wherein the method is as follows.
Tcr = a x Tav + b... (1)
However, in the equation (1), a and b are constants determined by the structure of each coke oven.

According to the present invention, without utilizing the peak of the gas temperature generated in the final stage of carbonization, the completion of carbonization is determined by using the temperature gradient when the temperature of the gas generated falls, so the gas temperature in the final stage of carbonization is determined. It is possible to accurately determine the completion of carbonization even with carbonization in an aged coke oven in which the peak does not appear. As a result, stable production of coke and reduction of coke production cost are achieved.

It is a figure which shows an example of the chamber furnace type coke oven used when implementing the dry distillation completion determination method which concerns on this invention, and is sectional drawing which shows some chamber furnace type coke ovens. It is a figure showing a time series change of generated gas temperature and an outline of a dry distillation completion judging method concerning an embodiment of the present invention. It is a figure which shows the monthly change of the determination failure before and after applying this invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing an example of a chamber furnace type coke oven used when carrying out the dry distillation completion determination method according to the present invention, and is a cross-sectional view showing a part of the chamber furnace type coke oven.

As shown in FIG. 1, the chamber furnace type coke oven 1 includes a carbonization chamber 2 for carbonizing coal 8, a rising pipe 3 installed above the carbonization chamber 2, and a curved pipe installed on a side surface of the rising pipe 3. 4 and a collecting pipe 5 connected to the curved pipe 4. A coke oven 1 having a chamber furnace is formed by horizontally connecting several tens to hundreds of carbonization chambers 2 having such a configuration. The carbonization chamber 2 has a rectangular parallelepiped shape whose longitudinal direction is the left-right direction of the paper surface, and combustion chambers (not shown) are installed on both sides of the rectangular parallelepiped shape (directions perpendicular to the paper surface) with sidewalls made of refractory material. Has been done. Further, each carbonizing chamber 2 is connected to the collecting pipe 5 via the respective rising pipe 3 and curved pipe 4.

The combustion of the fuel gas in the combustion chamber raises the temperature of the side wall separating the combustion chamber and the carbonization chamber 2, and the temperature rise of this side wall heats the coal 8 filled in the carbonization chamber 2 to cause the carbonization reaction of the coal 8. Happens. The gas 9 generated by the dry distillation reaction reaches the collecting pipe 5 through the rising pipe 3 and the curved pipe 4. The collecting pipe 5 is connected to a gas holder (not shown) for collecting the generated gas 9.

A thermocouple 10 for measuring the temperature of the generated gas 9 is installed in the curved tube 4 through a thermocouple insertion tube 7. The tip end of the thermocouple 10 is located inside the curved tube 4, while the other end of the thermocouple 10 is connected to the temperature measuring device 11, and the electromotive force generated in the thermocouple 10 generates the thermocouple 10 in the temperature measuring device 11. The temperature of the gas 9 is measured.

The temperature measurement data obtained by the temperature measurement device 11 is transmitted to the dry distillation completion determination device 12. The carbonization completion determination device 12 determines the carbonization completion of the coal 8 based on the transmitted temperature measurement data. A top cover 6 that can be opened and closed is installed at the upper end of the rising pipe 3.

That is, in the chamber furnace type coke oven 1 for carrying out the method of judging the completion of carbonization according to the present invention, the generated gas temperature including the thermocouple insertion tube 7, the thermocouple 10 and the temperature measuring device 11 in one carbonization chamber 2. A measurement means and a dry distillation completion determination device 12 are arranged.

Usually, when coal 8 is dry-distilled to produce coke, and when the carbonization chamber 2 has almost the same shape as that at the time of construction, the temperature of the generated gas 9 rises when the dry-distillation starts and is dry-distilled at the end of the dry-distillation. The maximum temperature (peak temperature) is indicated by an increase in the amount of coal to be charged, and thereafter, when the carbonization progresses to the vicinity of the center of the filled coal 8, the temperature of the generated gas 9 drops.

However, due to deterioration of the chamber furnace coke oven 1, heat transfer from the combustion chamber 2 changes in the longitudinal direction of the carbonization chamber 2 and for each carbonization chamber due to wear of the side wall between the carbonization chamber 2 and the combustion chamber. When uniform carbonization cannot be performed, coal to be carbonized does not collect after a predetermined time has elapsed, and a peak of the gas temperature at the end of carbonization hardly appears. That is, the temperature of the generated gas 9 drops gently.

The present invention provides a method for accurately determining the completion of carbonization based on the temperature of the generated gas, even when the generated gas temperature is unlikely to have a peak in the final stage of carbonization and when the peak does not appear.

FIG. 2 shows a time series transition of the generated gas temperature and an outline of the dry distillation completion determination method according to the embodiment of the present invention. In FIG. 2, charging of the coal 8 into the carbonization chamber 2 is started at time t _S , and dry distillation is started. With dry distillation, the temperature of the generated gas 9 rises, and after that, the temperature of the generated gas 9 starts to drop after a period in which the temperature of the generated gas changes little. When a peak appears in the generated gas temperature, the temperature of the generated gas 9 starts to drop after the peak appears.

As shown in the “reference time and dry distillation completion time determination period” in FIG. 2, from the time when the temperature of the generated gas starts to drop, with respect to the temperature of the generated gas measured by the thermocouple 10, a predetermined time interval t _it (1 minute to At every 10 minutes interval, comparison of the immediately preceding gas temperature measurement value and the current gas temperature measurement value is started. Then, the first time point at which the gas temperature measurement value this time becomes lower than the immediately preceding gas temperature measurement value by the predetermined temperature difference Tcr or more is set as the reference time t ₀ .

The reference time t ₀ is a point in time when the gradient of the temperature drop of the generated gas temperature suddenly increases, that is, an inflection point of the temperature change, and appears at the final stage of carbonization. Here, the predetermined temperature difference Tcr changes according to the predetermined time interval t _it which is the time interval for calculating the difference between the measured temperatures, but if the predetermined time interval t _it is 1 minute to 10 minutes as described above. By setting the predetermined temperature difference Tcr in the range of 0.1° C. to 10° C., the dry distillation completion time can be reliably determined.

After the reference time t ₀ has elapsed, the temperature difference between the immediately preceding gas temperature measurement value and the current gas temperature measurement value is continuously calculated at each of the predetermined time intervals t _it , and this temperature difference is the predetermined value. The case where the temperature difference is equal to or more than Tcr is continued until the time when the predetermined number of times N is reached. When the temperature difference is equal to or larger than the predetermined temperature difference Tcr and the predetermined number of times N is reached, the time t ₁ from the reference time t ₀ until that time is obtained. Then, the time t ₂ obtained by adding the obtained time t ₁ to the reference time t ₀ is determined as the dry distillation completion time.

The predetermined number of times N is preferably 2 to 5 times. When N=1, the temperature difference may be less than the predetermined temperature difference Tcr after that, and the completion of carbonization cannot be accurately determined. Further, if N is 6 or more, it takes time to make the determination, and the work efficiency decreases.

When the temperature difference is equal to or greater than the predetermined temperature difference Tcr, the reason for determining that the dry distillation is completed when the number of times reaches the predetermined number N is that the gas temperature once decreases and then rises again by confirming it several times. This is to prevent erroneous detection of an inflection point of change. Further, the reference time t ₀ is an inflection point of the temperature that appears in the final stage of the carbonization, and the completion of the carbonization is after a further time has elapsed from the reference time t ₀ . The time t ₁ is a time for setting the time from the reference time t ₀ to the completion of dry distillation.

The time-series transition of the generated gas temperature changes depending on the generated gas temperature in the middle stage of carbonization. Particularly, the temperature drop gradient after the inflection point of the temperature change correlates with the temperature of the evolved gas in the middle stage of carbonization. That is, the higher the temperature of the generated gas in the middle of the dry distillation, the larger the gradient of the temperature drop after the inflection point of the temperature change. Therefore, it is preferable to change the predetermined temperature difference Tcr, which is an index of the temperature difference, according to the temperature of the generated gas in the middle of the dry distillation.

Therefore, in the present invention, the gas temperature measured during the period from the time t ₃ to the time t ₄ within a predetermined period (for example, 20% or more and 70% or less of the estimated carbonization time) of the estimated carbonization time. Is defined as an average gas temperature Tav, and this average gas temperature Tav is used as a representative value of the generated gas temperature in the middle of the dry distillation. That is, in the present invention, it is preferable to set the predetermined temperature difference Tcr, which is an index of the temperature difference, with reference to the average gas temperature Tav. This is based on the fact that the generated gas temperature changes little and the generated gas temperature is stable within a predetermined period of the assumed dry distillation time, as shown in FIG.

Specifically, it is preferable to obtain the predetermined temperature difference Tcr using the following equation (1).

Tcr = a x Tav + b... (1)
However, in the equation (1), Tav is the average gas temperature, a and b are constants determined by the structure of each coke oven, a is in the range of 0.0005 to 0.05, and b is -5 to -5. A range of 5 is good.

By setting the predetermined temperature difference Tcr which is an index of the temperature difference with the average gas temperature Tav as a reference, it is possible to accurately determine the completion of carbonization even if the average gas temperature Tav changes.

As explained above, according to the present invention, when the coal 8 is carbonized in the chamber furnace type coke oven 1 having the plurality of carbonization chambers 2 to produce coke, the peak of the gas temperature generated in the final stage of carbonization is determined. Since the completion of dry distillation is determined by using the temperature gradient when the temperature of the evolved gas falls without using it, the dry distillation in the aged chamber furnace type coke oven 1 in which the peak of the evolved gas temperature does not appear at the end of the dry distillation Even if there is, it is possible to accurately determine the completion of carbonization.

Using the room furnace type coke oven shown in FIG. 1, coal carbonization operation was carried out. The coal used is a coal type of pulverized coal of a normal blend prepared by blending such that the reflectance is 1.1 and the MF (Giesler fluidity) is 2.3.

The coal species was subjected to carbonization, and the completion of carbonization was determined by the method of the embodiment of the present invention. Specifically, the average gas temperature Tav is calculated by setting the time t ₃ to 10 hours after the coal charging and the time t ₄ to 12 hours after the coal charging, and the coefficient a of the equation (1) is 0.0056, (1) setting a predetermined temperature difference Tcr coefficients b as -0.4873 of formula 5 minutes for a predetermined time interval t _it, as 3 times the predetermined number N, to determine the dry distillation completion time.

Whether the completion of carbonization is good or bad is judged by a skilled person called "Himi" who ignites the generated gas discharged from the top cover and visually judges the color of the ignited flame. Only the carbonization chamber that was determined to have completed the carbonization before 20 hours had elapsed after the charging of coal to the comparison target, and the carbonization completion time (time t ₂ ) determined by the determination method according to the present invention was 20 hours. The case where it became the above was judged to be defective.

FIG. 3 shows a monthly transition of the determination failure before and after applying the present invention. Prior to the application of the present invention, it is a method of determining the completion of carbonization when the temperature of the generated gas measured in the curved pipe reaches a predetermined value set according to the amount of coal charged.

As shown in FIG. 3, it was confirmed that by applying the present invention, the determination failure was 1/3 or less of that in the conventional case, and coke having desired characteristics could be produced without wastefully extending the dry distillation time.

1-chamber furnace coke oven 2 carbonization chamber 3 rising pipe 4 curved pipe 5 collecting pipe 6 top cover 7 thermocouple insertion pipe 8 coal 9 generated gas 10 thermocouple 11 temperature measuring device 12 carbonization completion determination device

Claims (2)

In a carbonization chamber of a coke oven having a plurality of carbonization chambers, the temperature of the gas generated during the carbonization reaction of coal in each of the carbonization chambers is measured at predetermined time intervals t _it ,
The average value of the gas temperature measured during the period from time t ₃ to time t ₄ within the period of 20% or more and 70% or less of the assumed dry distillation time is defined as the average gas temperature Tav, and the previous gas temperature is determined. The measured value and the measured value of the gas temperature at this time are compared, and the measured value of the gas temperature at this time is lower than the measured value of the previous gas temperature by a predetermined temperature difference Tcr which is set based on the average gas temperature Tav. The first time point is the reference time t ₀ ,
With the reference time t ₀ as the start time, the temperature difference between the immediately preceding gas temperature measurement value and the current gas temperature measurement value is continuously calculated, and the temperature difference becomes the predetermined temperature difference Tcr or more. In this case, the time until the predetermined number of times N is reached is time t ₁ .
Wherein characterized in that the reference time t ₀ by adding the time t ₁ to time t ₂ required to determine that carbonization completion time, carbonization completion determining method in a coke oven. The dry distillation completion determination method in a coke oven according to claim 1, wherein the predetermined temperature difference Tcr is obtained using the following equation (1) with the average gas temperature Tav as a reference.
Tcr = a x Tav + b... (1)
However, in the equation (1), a and b are constants determined by the structure of each coke oven.

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