JPS62232484A - Method for controlling coke level in cooling tower - Google Patents

Abstract

PURPOSE:To control the coke level within a suitable range in a cooling tower in a low-cost, high-precision, highly reliable manner, by calculating a coke storage amt. according to a weight method and by correcting the result of calculation result with the result of measurement of the coke level within the cooling tower obtd. with a microwave level meter. CONSTITUTION:The coke amt., Yi, in the tower is obtd. in terms of wt. by calculating with an operating device 19 according to equation I by inputting as a cut-out signal 12b the amt. of extracted coke calculated by multiplying a constant predetermined on the basis of the size of discharge aperture 5 by the number of extractions and by inputting as an insertion signal 14 the amt. of fed coke calculated from the difference between wind-up and wind-down with a load cell 11 of the winding machine. This Yi is converted to operation level, yi, according to equation II. On the other hand, the signal of a microwave level meter 15 is input as correct signal X (t) only when a signal 16 showing that the meter 15 is ON. The input signal is instructed to a level indicator 17, and a correction parameter is calculated with an operating device 20. Using this parameter, the above-mentioned operation level, yi, is corrected.

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.

A bucket of red hot coke extruded from a coke oven)
A hoisting machine 9a equipped with a load cell 11 inserted into the winding machine 8a
(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 a fan 4 to cool the red-hot coke 10, and the gas itself is heated and sent through the flue 2 to a boiler (not shown). 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 the gate 12a is opened at the appropriate time.
By opening the conveyor 6a, 6 through the discharge port 5.
(b) and sent to the next process, such as a blast furnace, as extinguishing coke.

Level management of the red hot coke lO 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 has been managed by gamma ray upper and lower limit level switches 13a and 13b.

When the red hot coke lO crosses the lower limit, the γ-ray lower limit level switch 13b turns off and on (the γm-h limit switch 13a remains on), and when it exceeds the upper limit, the γ-ray upper limit level switch 13a turns on→off (the γ-ray lower limit level switch 13.b remains off). red hot coke 1
The charging amount and discharge amount are adjusted so that the coke level is between the upper and lower limits. It becomes something big. In order to improve this, there is a mass balance method that measures the charging weight using a load cell 11 installed in the charging vehicle (
Patent application Sho 6O-206948).

The mass balance calculation is performed using the following formula.

Yo: Initial value (ton) Wj: Amount of coke charged at the jth time (measured with load cell 11) ('ton) M: Number of cuttings from the initial time Q: Amount of one cutting (ton) (discharge port 5 (a constant value determined by the size of the coke) N: Number of charging up to the number of i-th cutting i: i = M1N Yj = Remaining amount of coke after M-th cutting and N-th charging (ton) Above Since there is no means to measure the cutting amount Q in the invented method,
Since it is a fixed value and therefore errors accumulate, fixed point correction is performed using the signals from the gamma ray upper and lower limit level switches 13a and 13b shown above.

That is, when each signal is input, YO in equation (1) is adjusted so that Yi at that time becomes the corresponding amount (fixed amount corresponding to the upper limit or lower limit). Actually, for example, γ
When the line lower limit level switch 13b is activated, M and N may be set to O, and the initial value yo may be set to an amount corresponding to the upper limit. (ΣWj=M·Q-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 γ-ray level switch.

In Fig. '9, □ shows time on the horizontal axis and coke level on the vertical axis. It has been found that this method also has the following problems.

・(1) As shown at lower limit correction point A in Figure 9, at the lower limit ・
The correction point jumps significantly from point a to point b, and...
The accuracy is poor unless the measurement accuracy reaches the correction point.

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

(3) Because gamma rays (radiation) are used to measure coke levels, management efforts to ensure safety are large.

The present invention solves these problems by combining a single microwave level meter and the mass balance calculation of equation (1). (C) provides a highly accurate and (d) highly reliable level management method.

[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.

(2) Since the gravimetric method always causes cumulative errors, a microwave level meter installed separately in the cooling tower is used to correct the calculated value in (2) above.

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 this case, the coke inventory in the cooling tower is controlled to within a certain level. There is a need.

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 with the load cell of the hoist and using the difference in unwinding, and on the other hand, calculates the amount of coke taken out by using the load cell of the hoist. The coke inventory amount is calculated by multiplying the fixed value determined by the number of withdrawals by the number of withdrawals, and the amount of coke inventory calculated from the difference between the two is corrected by the measurement results of a microwave level meter installed separately in the cooling tower.The amount of coke inventory can be determined quantitatively. Measure accurately.

[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 a device that preferably implements the present invention.
FIG. 3 shows an explanatory diagram (1) of the correction calculation of the present invention. The signal of the microwave level meter 15 is a correct signal x(
t) and is indicated to the level indicator 17. (
A lower limit timing signal 17a (the level at that time is Lh and Ll, respectively) is used to supply the level indicator 17 with the timing of the mass balance correction calculation (described later). Have 17b.

On the other hand, the load cell 11 of the hoisting machine, the charging signal 14 at the tower top 7
, the amount of coke in the tower is calculated by the calculation device 19 using equation (1) based on the cutting signal 12b from the bottom of the tower. The cutting amount setting device 1B calculates the cutting amount Q (t on) of one time using the formula (1).
It is a manual setting device that gives Yi calculated by equation (1)
is the weight, which is changed to the calculation level using the following equation. Figure 84 shows an approximate explanatory diagram of the remaining amount of coke and the coke level.

yr=(Yt Cz)/C2+yo-・”(2)y
L: Coke level when remaining amount Y4 (ton) C1: Constant (coke amount (ton) when at reference level Vo) C2: Constant (cooling tower cross-sectional area x coke specific gravity) yo: Coke reference level obtained here Since the level y[ has many terms that may include errors, such as Q in equation (1), Cm in equation (2), and c2, correction is performed as appropriate using the method described later using the microwave level meter signal X(t). Reference numerals 20 and 21 in the explanatory diagram of the correction calculation in FIG. 3 are a correction parameter calculation device and a mass balance calculation value correction device. Also.

VL is a level signal based on corrected mass balance, and 22 is its indicator.

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

First, let me explain the movement of coke level. Charging from the top 7 of the column raises 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. Become. In addition, the time when charging is stopped (q in Figure 5)
), the shape becomes even larger and 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 it is This is the second cutting. It is assumed that the mass balance calculation level value at the completion of i (k) times of L1 cutting is Vtk, and the microwave level meter indicated value is xk. However, k indicates the second 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 xk is stored in memory A in the correction parameter calculation device 20, and the balance calculation value level value yr(k) is stored in memory B. Put in.

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. 6(b). Assuming that the mass balance calculation level value immediately after charging is yt(k), and the indicated value of the microwave level meter is xk, xk is stored in memory C in FIG.
Insert y t (ic) into .

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

bk=A−ak *B・”−(4) Here, ak and tlk are parameters for correction, A, B, C,
D is the content of the memory shown in FIG. 7, and α is a smoothing constant to avoid sudden changes in ak and bk.

The level value obtained by the calculation is applied to the calculation value correction device 21 to perform correction calculation according to the following equation.

yi:ak0yi+bk...Dan...(7)
yt is the raw data of the balance calculation, and Vt is the data after correction, which is displayed on the calculation correction value indicator 22 and used as a backup in case of a failure of the microwave level meter.

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 to back up 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 1. The vertical axis shows the amount of 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 management can be performed continuously using the signal from the microwave level meter, which is a measured value of the actual level, and the accuracy of the management 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 management can be improved at low cost.

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

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 plot 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. 4 is a rough explanatory diagram of the remaining coke amount and coke level of the present invention, No. 5
The figure is an explanatory diagram of the transition of coke level and the timing of correction according to the present invention, and Fig. 6 is a diagram illustrating the details of the correction according to 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. l... Cooling tower main body 2 of coke dry extinguishing equipment... Flue 3... Return piping 4... Fan 5... Discharge ports 6a, 6b... Conveyor 7... Tower top 8a, b, c...Buckets 9a, 9b...Hoisting machine 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 15...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

Claims (1)

[Claims] 1. Measure the weight of the coke hoisting bucket of the coke dry 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. 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 correcting the measured value.