JPH0468357B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling coke levels in a cooling tower of coke dry extinguishing equipment.

[Conventional technology]

FIG. 8 is a block diagram of coke level management in a cooling tower of a conventional coke dry extinguishing system. First, I will briefly explain the level management process.

Red-hot coke 10 extruded from the coke oven is charged into a bucket 8a and transported to the upper part of the coke dry extinguishing system cooling tower 1 by a hoist 9a equipped with a load cell 11 (8b). The bucket is then lowered onto the tower top 7 (8c), the bottom gate is opened, and the red hot coke 10 is charged into the cooling tower body 1. On the other hand, gas for cooling the red-hot coke 10 is pushed in from the bottom of the tower by the fan 4, cooling the red-hot coke 10, and the gas itself is heated and sent to the boiler (not shown) through the flue 2. It will be done. The gas used to generate steam in the boiler returns to the fan 4 through the return pipe 3 in a cooled state.
circulate.

The red-hot coke 10 is gradually cooled, and by opening the gate 12a at appropriate times, it is led to the conveyors 6a, 6b through the discharge port 5 and sent to the next process, such as a blast furnace, as extinguished coke.

Level control of the red hot coke 10 in the cooling tower body 1 is essential for efficient operation of the equipment and stable and safe operation, such as optimizing the cooling efficiency of the red hot coke 10 and sensible heat recovery by the boiler. Conventionally, this was controlled by upper and lower limit level switches 13a and 13b for gamma rays.

When the red hot coke 10 falls below the lower limit, the γ-ray lower limit level switch 13b changes from off to on (γ-ray upper limit switch 1
3a remains on), and when the upper limit is exceeded, the gamma ray upper limit level switch 13a changes from on to off (the gamma ray lower limit level switch 13b remains off). The charging amount and discharge amount are adjusted so that the amount of red hot coke 10 is within these upper and lower limits, but as it is, it is guaranteed that the coke level will be between the upper and lower limits, but the coke level will not fluctuate. It becomes something very big. A load cell 11 installed on the charging vehicle was invented to improve this.
There is a mass balance method that measures the weight of the charge (Japanese Patent Application No. 60-206948).

The mass balance calculation is performed using the following formula.

Yi=Yo+ _N 〓 ^j=1 Wj−M・Q……(1) Yo: Initial value (ton) Wj: j-th charging coke amount (load cell 1
1) (ton) M: Number of cuttings from the initial point Q: Amount of one cutting (ton) (a constant value determined by the size of the discharge port 5) N: Loading up to the i-th cutting number Number of inputs i: i=M+N Yi=Amount of coke remaining after M-th cutting and N-th charging (tons) In the method of the invention described above, since there is no means to measure the cutting amount Q, it is set as a fixed value, and Since errors accumulate over time, fixed point correction is performed using the signals from the gamma ray upper and lower limit level switches 13a and 13b shown above.

In other words, at the time each signal is input, Yo in equation (1)
Adjust so that Yi at that time becomes the corresponding amount (fixed amount corresponding to the upper or lower limit).
In practice, for example, when the gamma ray lower limit level switch 13b is activated, M and N are set to 0, and the initial value Yo
may be set to an amount corresponding to the upper limit. (〓Wj
=MQ=0) [Problems to be Solved by the Invention] FIG. 9 shows an example of the correction results of the mass balance method in which correction is performed using a conventional gamma ray level switch. In FIG. 9, the horizontal axis shows time and the vertical axis shows coke level. It has been found that this method also has the following problems.

(1) As shown in the lower limit correction point A in FIG. 9, the correction point at the lower limit has a large jump from point a to point b, and the measurement accuracy is poor unless it reaches the correction point.

(2) Discontinuity in the indicated value occurs at the above jump point, causing confusion in operations.

(3) Gamma rays (radiation) are used to measure coke levels, which requires a lot of management effort to ensure safety.

The present invention solves these problems by combining a single microwave level meter and the mass balance calculation of equation (1), thereby (a) making it inexpensive and (b) using only a measuring device that is easy to manage from a safety standpoint. It provides a level control method that is (c) highly accurate and (d) reliable.

[Means for solving problems]

In order to solve the above problems, we decided to calculate using the gravimetric method and improve the accuracy by correcting the calculation results based on the results of measuring the coke level in the cooling tower using a microwave level meter.

As a specific technical measure, a bucket load cell is installed on the cooling tower hoisting machine to calculate the charging amount of the cooling tower, and the discharge amount is calculated by multiplying the number of cuttings by a fixed cutting amount determined by the size of the discharge port. and calculate the amount of coke in stock.

Since the gravimetric method always produces cumulative errors, a microwave level meter installed separately in the cooling tower is used to correct the above calculated values.

In coke dry extinguishing equipment, coke extruded from a coke oven is put into a cooling tower, and the coke cooled by circulating gas is extracted from a cutting valve.
In that case, it is necessary to control the amount of coke stock in the cooling tower within a certain level.

In order to control the coke level in the cooling tower within an appropriate range, the present invention calculates the amount of coke thrown in by hoisting up the coke amount using the load cell of the hoist and using the difference in unwinding, and the amount of coke taken out from the outlet. By multiplying a fixed value determined by the size of the number of withdrawals by the number of withdrawals, and calculating the coke inventory amount by the difference between the two, the coke inventory amount is corrected by the measurement results of a microwave level meter installed separately in the cooling tower. To quantitatively and accurately measure coke inventory.

[Effect]

The present invention uses load cells, microwave level meters, etc. to calculate and manage coke inventory in cooling towers, stabilizes and improves coke operation rate, and increases coke sensible heat recovery efficiency in coke dry extinguishing equipment. , the danger of coke overflow can be prevented.

FIG. 1 shows a block diagram of an apparatus that preferably implements the present invention, and FIG. 3 shows an explanatory diagram 1 of the correction calculation of the present invention. The signal from the microwave level meter 15 is taken in as a correct signal X(t) only when the signal 16 indicating that the device is operating normally is ON, and is indicated to the level indicator 17. (Reference level Yo to be described later)
The level indicator 17 is provided with lower limit timing signals 17a and 17b (the levels at that time are Lh and Ll, respectively) in addition to providing the timing for the mass balance correction calculation described later.

On the other hand, by the load cell 11 of the hoisting machine, the charging signal 14 at the tower top 7, and the cutting signal 12b from the tower bottom,
The amount of coke in the column is calculated by the calculation device 19 using equation (1). The cutting amount setting device 18 is a manual setting device that gives the cutting amount Q (ton) of one time according to the equation (1). Yi calculated by equation (1) is weight, which is changed to calculated rubel by the following equation. FIG. 4 shows an approximate explanatory diagram of the remaining amount of coke and the coke level.

Yi = (Yi - C ₁ ) / C ₂ + yo ... (2) yi: Coke level when remaining amount Yi (ton) C ₁ : Constant (coke amount (ton) when at reference level Yo) C ₂ : Constant (Cooling tower cross-sectional area x coke specific gravity) yo: Coke standard level The level yi obtained here is Q in equation (1),
Since there are many terms that may include errors such as C ₁ and C _2, correction is performed as needed using the method described later using the microwave level meter signal X(t). 20 in the explanatory diagram of the correction calculation in Fig. 3,
21 is a correction parameter calculation device and a mass balance calculation value correction device. Further, y to i are level signals based on corrected mass balance, and 22 is an indicator thereof.

FIG. 5 shows an explanatory diagram of the timing of correction.

First, let me explain the movement of coke level. Tower top 7
Charging from the bottom of the column increases the coke level, and cutting from the bottom of the column lowers the coke level, but because the frequency of cutting is greater than the frequency of charging, the level transition usually takes a sawtooth shape. Furthermore, since there is a time when charging is stopped (q in Fig. 5), such as during meal breaks, the shape becomes even more undulating.

As shown in the enlarged part of Fig. 5, the lower limit correction point is cut at the time of cutting out, and as shown in the detailed explanatory diagram at the time of lower limit correction in Fig. 6a, the i(k)th cutout is performed. shall be. Let the mass balance calculation level value at the completion of the i(k)th cutting be y _ik , and the indicated value of the microwave level meter be X _k . However, k indicates the kth correction.

As shown in the explanatory diagram of the correction calculation in FIG. 7, in the case of lower limit correction, the microwave level meter indicated value X _k is stored in memory A in the correction parameter calculation device 20, and the balance calculation value level value y _i ( Enter k).

Next, in the case of upper limit correction, the upper limit correction point is exceeded at the time of charging, as in the case of FIG. 6b. Assuming that the mass balance calculation level value immediately after charging is y _i (k), and the indicated value of the microwave level meter is X _k , the memory C in Fig. 7 is
Put X _k into memory D and y _i (k).

The following calculations are performed for both the upper and lower limits after the above processing.

a _k =C-A/D-B ……(3) b _k =A-a _k・B ……(4) a^ _k =α・a _k +(1−α)a^ _k-1 …… (5) b^ _k = α・b _k + (1-α) b^ _k-1 ...(6) Here, a _k and b _k are parameters for correction, A, B,
C and D are the contents of the memory shown in Figure 7, α is a _k ,
b is a smoothing constant to avoid sudden changes in _k .

a^ _k and b^ _k are smooth values of a _K and b _K.

The a^ _k and b^ _k obtained by the above calculations are given to the level value computation value correction device 21 based on the mass balance computation, and a correction computation according to the following equation is performed.

y ~ = a^ _k・y _i + b^ _k ...(7) y _i is the raw data of the balance calculation, y ~ _i is the data after correction, and this is displayed on the calculation correction value indicator 22, and the microwave Used as a backup in case the level meter breaks down.

To simply monitor coke levels, it is sufficient to replace conventional technology with a microwave level meter, but with only a single device, if it were to fail, inventory control would be completely absent and operations would be interrupted. becomes impossible. The load cell of the hoist is an essential signal for the operation of the hoist, and is a device attached to the coke dry extinguishing equipment. This signal is used for backup for inventory management.

〔Example〕

FIG. 2 shows a measurement example using the microwave level meter of the present invention and a level value obtained by mass balance calculation according to the present invention. In Figure 2, the horizontal axis shows time and the vertical axis shows coke inventory.

〔Effect of the invention〕 The effects of the present invention are as follows.

(1) There is no need to set up a gamma ray level meter, which is a radiation meter that poses many problems in terms of safety management, increasing the safety of the equipment.

(2) Level control can be performed using the microwave level meter signal, which is a continuous measurement value of the actual level, and the accuracy of the control can be improved.

(3) By backing up the microwave level meter using a signal from a measuring device that does not require any new investment, the reliability of level control can be improved at low cost.

(4) The accuracy of the calculated balance value can be improved by constantly correcting the calculated balance value using the microwave level meter, which is an actual measured value.

Based on these results, it is possible to constantly manage the coke level in the cooling tower of the coke dry extinguishing equipment with high accuracy and reliability, and to obtain appropriate coke extinguishing and heat recovery.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a device that preferably implements the present invention, FIG. 2 is a graph of an example of measurement by the microwave level meter of the present invention, FIG. 3 is an explanatory diagram of the correction calculation of the present invention, and FIG. Fig. 5 is an explanatory diagram of the approximate amount of coke remaining and coke level of the present invention, Fig. 5 is an explanatory diagram of the coke level transition and correction timing of the present invention, and Fig. 6 is a detailed explanatory diagram of the correction time of the present invention. 7 is an explanatory diagram of the correction calculation of the present invention, FIG. 8 is a block diagram of a conventional device configuration example, and FIG. 9 is a graph of a conventional correction example. 1... Cooling tower main body of coke dry extinguishing equipment, 2
... Flue, 3... Return pipe, 4... Fan, 5...
...Discharge port, 6a, 6b...Conveyor, 7...Tower top, 8a, b, c...Bucket, 9a, 9b...
Hoist, 10... Red-hot coke, 11... Load cell, 12a... Gate, 12b... Cutting signal,
13a...γ-ray upper limit level switch, 13b...
γ-ray lower limit level switch, 14...Charging signal, 1
5...Microwave level meter, 16...Microwave level meter normal signal, 17...Microwave level indicator, 17a...Upper limit timing signal, 17b...
...lower limit timing signal, 18...cutting amount setting device,
19... Mass balance calculation device, 20... Correction parameter calculation device, 21... Mass balance calculation value correction device, 22... Mass balance calculation correction value indicator.

Claims (1)

[Claims] 1. Measure the weight of the coke hoisting bucket of the coke dry fire extinguishing system, calculate the amount of coke charged into the cooling tower from the difference in weight between the actual car and the empty car, and extract the amount of coke discharged from the cooling tower to a fixed value determined by the size of the discharge port. The amount of coke stock in the coke cooling tower is calculated from the difference between the amount of charged coke and the amount of coke withdrawn, and the calculated value is used as a microwave level meter that measures the coke level in the cooling tower. 1. A method for controlling coke level in a cooling tower of a coke dry extinguishing system, characterized in that the coke level in the cooling tower is controlled within an appropriate range by performing correction calculations based on measured values.