JPS6383196A - Method of estimating and controlling coking time in coke oven - Google Patents

Abstract

PURPOSE:To accurately correct the coking time by measuring the flue temp. in each oven with the lapse of time, calculating the coking time from the time when the flue temp. becomes min., and controlling the amt. of heat supplied to each oven and the flow rate of air supplied thereto so that the coking time can agree with the target time. CONSTITUTION:A thermometer 14 is mounted on a partition brick 13 between a coke oven chamber 11 and a combustion chamber 12 provided in each oven of a coke oven. The flue temp. is measured with the lapse of time with the thermometer 14 to detect the time when the flue temp. becomes min. The coking time is calculated with an arithmatic unit 15 based on the time providing a min. value of flue temp. which is proportional to the coking time. The amt. of heat supplied to each oven and the flow rate of air supplied thereto are corrected by controlling a gas cock 16 and a waist valve 17, respectively, based on the deviation of the calculated coking time from the target coking time so that the actual coking time can agree with the target coking time to attain energy saving and obtain coke having stable and high quality.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for predicting and controlling coke oven fire-off time.

(Prior Art) Conventionally, a thermometer is installed in the combustion chamber or the hairpin section between combustion chambers, and the carbonization status of coal is detected from this temperature. However, although the temperature of the coal changes by 20 to 900 degrees Celsius during carbonization, the temperature measurement point of this thermometer only changes by 10 to 20 degrees Celsius, and although it does not accurately reflect the temperature change in the carbonization chamber. do not have. Furthermore, since the time constant of a coke oven is as long as 4 to 5 hours, it is difficult to quickly detect and control the state of coal carbonization. Furthermore, the temperature measurement point is affected by combustion conditions (gas calories, gas flow rate, air amount) as well as coal carbonization on both sides of the combustion chamber, making it difficult to accurately detect temperature changes.

Therefore, it is difficult to use this temperature change for predictive control of fire-off time.

Therefore, it is possible to install a thermometer in the curved part of the riser pipe to detect the peak temperature at the end of coal carbonization and predict the fire-fall time, but the point showing this peak temperature is 2 to 3 hours before the missing point. , which is shorter than the time constant of a coke oven, which is 4 to 5 hours.
It cannot be used to control the fire fall time.

(Technical Problem to be Solved by the Invention) The present invention accurately detects the coal carbonization status in the kilns on both sides of the coke oven, predicts the fire-off time, and based on this predicted value, supplies heat amount and air amount. Provided is a method for predicting and controlling a coke oven burn-off time, which aims to reduce variations in the burn-off time of individual ovens by adjusting the burn-off time.

(Means for Solving Technical Problems) The present invention provides a thermometer attached to a partition brick between a carbonization chamber and a combustion chamber configured in each individual kiln of a coke oven, and measures the flue temperature over time using this thermometer. Measure the temperature to detect the time when this temperature reaches its minimum value, calculate the fire-off time based on this time, and adjust the supply to each kiln based on the deviation between this calculated fire-off time and the target fire-off time. This is a method for predicting and controlling a coke oven burn-off time, which is characterized by controlling the amount of heat and air flow rate so that the burn-off time becomes a target burn-off time.

(Detailed Description of the Invention) The present invention will be described below with reference to the drawings. FIG. 1 shows a schematic diagram of a coke oven, in which thermometers 14 are installed in partition bricks 13 between a carbonization chamber 11 and a combustion chamber 12, respectively. The location where this thermometer 14 is installed receives changes in the temperature of the coal and the temperature of the combustion chamber equally, and the detection accuracy of the carbonization status of the coal is good.

The temperature detected by this thermometer 14 changes as shown in FIG. 2, for example, from the time the coal is charged until the coal is dropped. That is,
When the coal is initially charged, heat is stored at 900 to 1000℃, but the heat is radiated by charging the coal at room temperature, and after 2 to 3 hours, the temperature is about 5℃.
The temperature drops to 00℃, shows a minimum value, then rises as the temperature of the coal rises, and returns to the original temperature of 900 to 1 when taken out of the coke oven.
Return to 000℃.

Inflection points a and C of the flue temperature detected here.

The time at which the minimum value is reached is determined by the target fire-off time, the setting time, the previous actual fire-off time, and the setting time. In the present invention, the difference between the target time and the actual time to reach the minimum value is calculated by the calculator 15,
Based on this value, the amount of heat supplied from the gas cock 1B and the amount of air from the waste valve 17 are controlled to correct the fire-off time.

A specific calculation method performed within the calculator 15 will be described below.

[Calculation of target time showing minimum value] According to formula (1), the previous actual fire fall time NCTa.

The amount of heat stored in the partition brick is calculated based on the placement time STa. Next, using equation (2), the amount of heat storage in the partition brick obtained here and the target fire-off time N CT os S T
Time T that shows the minimum value based on o.

Calculate.

Q = 1 / (N CT a + S Ta)
x (al +a2 STa+a3 (STa)2
)...(1) T+ -1/ (NCTo +STO)X (bo +
1/NCTO-1+b2 NCTO-2>...(2) t)o -Q/ (NCTO+s"ro)x (Co
+c1NCTo-2+1/NCTo-3) al, al,
a3, bl, b2, Co5C! , C2: Prediction of constant fire-off time and NCT prediction (control amount for setting NCTo) If Ta is the actual value of the time showing the minimum value, the predicted value of the fire-off time is expressed by equation (3).

NCT-NCTO+1/NCT.

X (dl + d2 ΔT + d3 Δ72)...(3) ΔT
-Tl-Ta, d1, d2, d3' constant and N
In order to match the CT prediction with NCTo, it is necessary to adjust the supplied heat amount and air amount by the deviation, (4), (5)
Based on the correction amount of the supplied heat determined by the equation (6) and (7), the opening adjustment amount of the gas hook and waist valve is calculated using equations (6) and (7).

Determination of supply heat amount correction amount Δq.

Δq t = K s X N CT o/ (N C
T o -T > )Xq (T'1-Ta)
...(4) ΔQ""K2 3ΔQ to ΔQt-
1 at t-1, K2, Ks, constant, Δqt, Δqt-1:
Calculated adjustment amount gas cock for this and previous deviations,
Determination of waist valve opening correction amount ΔWc1ΔWa.

4Δq/q to ΔWc- (6) ΔW
a = K5 We ・” (7
) The standard supply heat amount of each kiln, , , Ks is a constant.

FIG. 3 shows an example of the control method of the present invention.

If the time at which the minimum value Ta of the measured flue temperature appears is later than the time at which the minimum value T1 of the target flue temperature appears, the opening degree of the gas cock is increased to increase the gas amount when the minimum value of the flue temperature is detected. do. At the same time, the opening of the waist valve is increased to increase the amount of air. In this way, the fire fall time is corrected and controlled to the target time.

FIG. 4 shows the relationship between the variation in minimum values and the variation in fire-off time. From this figure, the deviation of the time to reach the minimum value ΔT−
It can be seen that the fire-off time becomes faster in proportion to T, -"ra.

(Effects of the Invention) According to the present invention, since the fire-off time is controlled based on the time to reach the minimum value which is proportional to the fire-off time, the fire-off time can be accurately corrected to greatly reduce the variation in the fire-off time. This resulted in energy savings of approximately 20 to 30 Kcal/kg-coal, and the coke quality was stabilized and improved.

[Brief explanation of the drawing]

Figure 1 is a schematic cross-sectional view of the main parts of a coke oven, Figure 2 is a diagram showing changes in flue temperature over time measured with a thermometer, and Figure 3 is a diagram showing changes in flue temperature over time as measured by a thermometer.
The figure shows an example of the control method of the present invention, and FIG. 4 is an explanatory diagram showing the correlation between the deviation in the time when the flue temperature reaches the minimum value and the deviation in the fire-off time. 11... Carbonization chamber, 12... Combustion chamber, 13... Partition brick, 14... Thermometer, 15... Arithmetic unit, 1G
...Gas cock, 17...West valve. Applicant's agent: Patent attorney Takehiko Suzue - deviation ANCT = NCTa - NCT. Figure 4 Procedural Amendment 61, 11.12 Showa Year, Month, Date Commissioner of the Patent Office Black 1) Mr. Akio, 1. Display of the case Japanese Patent Application No. 61-227986 2, Title of the invention: Predictive control method for coke oven fire-down time 3, Person making the amendment Relationship to the case Patent applicant (412) Nippon Kokan Co., Ltd. 4, Agent Tokyo UBE Building 7, 3-7-2 Kasumigaseki, Chiyoda-ku,
Contents of amendment (1) In box 5, line 7 of the specification, rX (a +a ST, a+a (STa)2
) Jl 2 3 rX (a +a STa+a3 (STa)
) Jl2. (2) On page 6, lines 12 and 13, it is stated that “2
Δq-to 3 Δqt-1K1, K2, K3, constant,
Δqt, Δqt-t: J means 3 to Δq-・K2ΔQ-2 to Δqt-1K1%
, K3, constant, Δq 1Δq:”t ,,L
-, t.

Claims (1)

[Claims] A thermometer is attached to the partition brick between the carbonization chamber and combustion chamber in each individual kiln of a coke oven, and this thermometer measures the flue temperature over time to detect the time when this temperature reaches its minimum value. Then, the fire-off time is calculated based on this time, and the amount of heat supplied to each kiln and the air flow rate are controlled based on the deviation between the calculated fire-off time and the target fire-off time, thereby reducing the fire-off time. A method for predicting and controlling a coke oven burn-off time to achieve a target burn-off time.