JPS597751B2 - Method for predicting fire-down time of coke oven - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coke oven burn-off time prediction method for predicting the time when carbonization of coal charged in a coke oven carbonization chamber is completed (hereinafter referred to as burn-off time).

In a coke oven, the conventional method for predicting the burnout time is based on the characteristics of the charged coal, such as the amount of charged coal, moisture content, particle size, and volatile content, and the average furnace temperature of the combustion chambers on both sides of the coking chamber from coal loading to the burnout. There is a method of predicting the fire-fall time from
Predicting the firefall time 0 hours in advance involves large errors and is inaccurate, and the above method could not be put to practical use as a method for predicting firefall in the carbonization chamber.

In addition, in another method, the correlation between the generated gas temperature Y at the time of fire-break and the elapsed time X from coal loading to fire-break is calculated using the following formula Y = a There is a method of determining the fire-break time when the measured temperature value of the riser pipe section that discharges generated gas and the elapsed time from coal loading satisfy the correlation equation, but this method is based on the change in the temperature of the generated gas. Since the temperature of the generated gas is constantly measured and actual measured values are used, tar contained in the generated gas adheres to the temperature measuring device, causing the detected temperature to become inaccurate over time.

In addition, the temperature of the generated gas changes depending on the temperature measurement location, air temperature, and climatic conditions such as rainy weather, making it impossible to accurately predict the time of fire.

As described above, the conventional method has problems in that the prediction of the fire-off time is inaccurate, resulting in large variations in coke quality due to combustion energy loss due to excessive carbonization and insufficient carbonization.

This invention proposes a method for predicting the fire-off time of a coke oven, which aims to eliminate the above-mentioned drawbacks.

The present invention will be explained below with reference to the drawings.

As shown in FIG. 1, the inventor inserts a thermocouple 3 into the bent part of the riser pipe 2 of the coke oven 1 and continuously measures the temperature of the generated gas discharged from the carbonization chamber 4. It was found that when the gas temperature reached its maximum value, the coal bed in the carbonization chamber had reached a certain state during the carbonization process.

Note that 5 is a generated gas collection duct.

The total amount of heat required for coal carbonization from the time the above condition is reached to the time of fire-off is uniquely determined once the furnace type (normally, once the furnace type is determined, the amount of charged coal is constant) .

On the other hand, the amount of heat input into the combustion chamber per unit time cannot be measured due to the equipment structure of the coke oven, but the average value of the combustion chamber temperature from the time of coal loading to the maximum temperature of the generated gas is measured per unit time during the same period. Since it is determined by the amount of heat input per unit time, the amount of heat input per unit time can be calculated from the average temperature.

Therefore, it was discovered that if the furnace type is the same, the total amount of heat required until fire-off is uniquely determined, and once the combustion chamber temperature is determined, the time required until fire-off can be determined.

In other words, this invention measures the temperature of the generated gas in a coke oven at regular intervals, determines the time when the generated gas reaches its maximum temperature based on the temperature change, and the temperature of the generated gas reaches its maximum temperature from the time of coal loading and from the combustion start time. The average temperature of the combustion chamber is measured over a period of time, and the fire-off time of the coke oven is predicted using this average temperature through the relational expression shown below.

t: Time from the time of the maximum temperature of the generated gas until it burns out, a1, a2: Coefficient determined by the furnace, Average temperature of the combustion chamber from the time of TF double coaling until the temperature of the generated gas reaches the maximum temperature, CI" The average value of 1/'I' F obtained from past data, the above generated gas temperature rises monotonically until reaching the maximum temperature after exceeding a certain temperature value, and changes slowly near the maximum temperature. After that, there was a monotonous cooling process, which led to the collapse of the flames.

In this way, the temperature of the generated gas undergoes a constant temperature change process, so when determining the maximum temperature of the generated gas, it is easy to find the maximum temperature of the generated gas by successively determining the difference in the temperature of the generated gas at predetermined intervals. The maximum temperature of generated gas can be determined.

Further, when determining the average temperature TF of the combustion chamber, it can be easily determined by dividing the sum of the measured temperatures by the number of measurements.

Note that the time t from the time of the maximum temperature of the generated gas to the end of the fire is t.

If the maximum temperature time of the generated gas is tp, then t=t
It is expressed as c-tp, and as soon as the detection time of the two highest temperatures of the generated gas is known, the fire-off time can be determined from equation 1) of the heat quantity relation.

In the firebreak time prediction method using equation 1) above, the maximum temperature of the generated gas measured at the bend in the riser pipe is not used as an actual measurement value, but is used to determine the time when the generated gas reaches the maximum temperature. Therefore, there is no problem even if tar or the like adheres to the temperature measuring device and the temperature is lower than the true temperature, or if the temperature of the generated gas fluctuates due to the influence of outside air temperature, the position where the thermometer is installed, etc.

Next, prediction of fire-fall time according to the present invention will be explained in detail based on the block diagram of FIG. 2.

A generated gas temperature measuring device 6 is provided at the bend of the riser pipe above each carbonization chamber of the coke oven, and continuously measures the temperature of the generated gas from the carbonization chamber.

The temperature value measured by the generated gas temperature measuring device 6 is:
The generated gas temperature is transmitted to the maximum temperature calculation device 7, and within the device 7, the generated gas temperature measurement device 6
Calculate the maximum temperature by comparing the values received from ), and the time when (current value) - (previous value)≦0 is reached is set as the time of maximum temperature and transmitted to the average temperature calculation device 9.

On the other hand, a combustion chamber temperature measuring device 8 for continuously measuring the atmospheric temperature of the combustion chamber is installed in the upper part of the combustion chamber, and the temperature signal measured by the combustion chamber temperature measuring device 8 is sent to an average temperature calculating device 9. Sent.

In the average temperature calculation device 9, temperature measurement is performed every fixed time, for example, 2 times, based on the temperature measurement signal from the combustion chamber temperature measurement device 8 from the coal loading time.
At the same time as adding temperature values sequentially every minute, the addition frequency is also calculated, and when the signal from the maximum temperature calculation device 7 is received, the added temperature value is divided by the addition frequency, and from the coal loading time. The average temperature TF in the combustion chamber until the generated gas temperature reaches the maximum temperature is calculated and transmitted to the calculation device 11.

In the arithmetic device 11, a formula for calculating the fire-off time is stored in advance, and the TF value from the average temperature calculation device 9 and the values of a1, a2, and c1, which have been actually measured and determined in advance, are set. The value of t, that is, the time until the fire break is calculated from the values of a1, a2, and C1 from the setting device 10, and the calculated fire break time is displayed on the display device 12, and at the same time, a As the time passes, the timer will also display the time until the end of the fire.

The method of the present invention was applied to a coke oven in actual operation (furnace length: 16,500 mm).
mm, oven width: 4507111 mm, oven height: 7125 mm), we measured the gas temperature of the coke oven, the combustion chamber temperature, and the actual time of fire (coal temperature was measured at 950 mm).
The measurement experiment (the time when the temperature reached ℃ was defined as the fire-off time) was repeated, and the elapsed time t from the time of the maximum temperature of the generated gas to the time of actual fire-off and the time from coal loading to the time of the maximum temperature of the generated gas on both sides of the carbonization chamber were repeated. After determining the average temperature TF of the combustion chamber and determining the average value C1 of 1/TF, a linear regression equation between t and (1/TF-C1) was obtained.

Then, the generated gas temperature and combustion chamber temperature of the coke oven are measured, and the combustion chamber temperature average value TF on both sides of the coking chamber from coal loading to the maximum generated gas temperature time is determined, and predetermined a1, a
2. Using the value of C1, the fire fall time calculation formula t-a1+a2
After calculating the time t until the fire falls from (1/lrF-C1), the fire fall time tcO value obtained from tc = t + ip (tp...the time of maximum temperature of the generated gas) and the actual fire fall time. The time t.

0 (determined by measuring coal temperature) t c − t o
o is shown in Figure 3.

From this result, the predicted firefall time can be calculated as follows:
It turned out that the 90th class would arrive within ±20 minutes.

As described above, according to the method of the present invention, it is possible to predict the fire-off time with high accuracy several hours before the fire-off time, and various adjustments of the coke oven can be made in advance with respect to the fire-off time, thereby improving the quality of coke. It has the effect of preventing deterioration and loss of carbonization heat source fuel energy.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of the upper part of the coke oven showing the measurement position of the generated gas temperature, Fig. 2 is a blank diagram for implementing the present invention, and Fig. 3 is the predicted value of the fire-off time of the present invention. It is a chart showing errors with actual values. 1... Coke oven, 2... Rising pipe, 3
...Thermocouple, 4...Carbonization chamber, 5...
... Generated gas collection duct, 6... Generated gas temperature measuring device, 7... Maximum temperature calculation device, 8...
... Combustion chamber temperature measurement device, 9 ... Average temperature calculation device, 10 ... Setting device, 11 ... Calculation device, 12 ... Display device.

Claims (1)

[Claims] 1. Continuously measuring the temperature of the generated gas generated in a coke oven and the temperature of the combustion chamber, and calculating the time to reach the maximum temperature of the generated gas while continuously comparing the temperature values of the generated gas, The average value TF of the combustion chamber temperature at the maximum generated gas temperature time is calculated from the addition value of the combustion chamber temperature every predetermined time and the addition frequency during the time until the maximum temperature is reached, and the average value TF of the combustion chamber temperature at the time of the maximum temperature of the generated gas is calculated. A method for predicting fire-off time of a coke oven, characterized by predicting fire-off time. t=al+a2(1/1F-Cl) t2 Time from the maximum temperature of the generated gas to the end of the fire. TF: Average temperature of the combustion chambers on both sides of the carbonization chamber from the time of coal loading until the generated gas temperature reaches its maximum. a1, a2: Constants determined by the furnace type, and are determined in advance through experiments using the same type of furnace. C1: Average value of actual value 1/TF during experiment.