SU1350850A2 - Method of controlling melting in three-phase three-electrode carbide furnace - Google Patents

Abstract

The invention relates to electrical engineering. The aim of the invention is to improve the quality of control and reduce the specific energy consumption by improving the accuracy of determining the length of the electrode and correcting the bypass mode. For periodic correction of the bypass mode, the consumption of active energy and amperage squares for each electrode is additionally measured, and the correction value is determined using the extracted formula. 1 il. co. ate about 00 cd N)

Description

1135

The invention relates to methods for controlling ore-thermal furnaces, for example, carbide and the like electric furnace installations, and is an improvement of the invention according to the author. St. No. 993491.

The purpose of the invention is to improve the quality of control and reduce the specific energy consumption by improving the accuracy of determining the length of the electrode and correcting the bypass mode.

The drawing shows the block diagram of the device that implements the proposed method of regulation.

The device consists of carbide. furnace 1 (control object), self-burning electrodes 2, current transformers 3, which are current sensors of the electrode, furnace transformer 4 with a switch of 5 voltage levels (PSN), which is a voltage sensor of the regulator 6, actuators 7 of the electrode or system reboot

ka, block 8 distance

electrode - under, blocks 9 comparing the actual and specified distance electrode - under, amplifier 10 and control devices 11, which drive the control signal to the regulators 6, integrators 12, block 3, comparing the position of the electrode - under the central and outer electrodes of the error amplifiers 14, connected to the regulator 6 and the loading system of the bins 15 through the device 11, and the unit 16 for determining the working length of the electrode, the output of which is connected through the regulator 6 to the electrode bypass system, the repair temperature measuring unit 17 calcium carbide, CaC determining unit 18 quality.

Additionally, the memory blocks 19, the active energy consumption meters 20, and the ampere square hours 21, the computing device 22, in which the equation

Wq; Tr

ь, п кк, (1)

de K

L0, 2 (i-p

about

(2)

constant coefficient; d, is the diameter of the electrode;

P - indicator

inertia;

P - averaged specific electric

to W

five

0

five

tric resistance of the interelectrode space, OM M;

coefficient depending on the average displacement. calcium carbide for the period of integration;

consumption of active energy of the i-th phase, MWh;

the value of the rms current of the i-ro electrode, kA; integration time (shift, day, period, etc.). In block 23, the comparison is the average value of the electrode - under distance, defined by the formula

but;

 T „H.

K 1 |

(3)

five

0

ilK -

where RD, - active phase power, MW; electrode current, kA; the coefficient determined by the formula (2),

is compared with the value of h ,,, is the actual, obtained in block 22 according to equation (1).

The output of the comparator unit 23 through the amplifier 10 is connected to the regulator 6, to which the signal for correction of the bypass amount is supplied.

In the period of operation between the by-pass, the electric mode controller 6 maintains a given active mobility on the electrodes by controlling the current value of the electrode. This happens in a known way. Two possible

The most common method of regulation is in power and current. If the regulation is carried out by current (Ig const) or by power (P const), then most often perturbation of the disturbance occurs due to the displacement of the electrode. The signal from the current sensor 3 is fed to the controller 6. The signal from the PSN 5 of the furnace transformer 4 also arrives here.

The optimum voltage on the electrode. In the controller, these signals are compared with the set ones. In case of deviation, a signal is given to the actuator 7 to switch the steps. Or to bypass the electrode, if the given power cannot be maintained by switching the voltage levels,

. In computational unit 8, the implementation of the equation

h if

The value of KD is compared in block 9 comparison with a predetermined value, which should be in the range of 0.7-0.9 d, g. In case of deviation from the specified range, the error signal is amplified by the amplifier 10 and fed to the control device 11, which outputs signals to the controller 6 and the batching system 15 to change the coke-lime ratio or stop the lime supply from the bunker 1

Simultaneously with the end of the determination of the distance of the electrode — in block 8, signals appear at the output of the latter, entering the integrator 12, where the value averages over a certain period of time, after which this signal enters the input of the control device 11.

To clarify the actual length of the electrode, periodically or at the request of the technologist determine the distance of the electrode - under the formula (1). Let the correction be carried out for the shift (the basic unit of work evaluation), and possibly for any other time.

Determine the consumption of active electricity by the formula

W K.,. ,

where K is the constant transformation ratio of the measuring transformer-meters; uNg, is the difference between the readings of active energy counters for the period in question.

We determine the rms currents in the electrodes from the readings of the counters of amperquadratic hours by the formula

i, .K ,, K. ,, (6)

5 where K.

ten

Oi

15

 .

& N.

T „20

25

- transformation ratio of current transformer;

- transformation ratio of the main furnace transformer;

-constant power meter amperkvadrat hours i-rc electrode (for meters of type F-440 Kz; 1, -. for other meters is determined individually);

-difference of the meter readings of amper-squares during T J time of the furnace operation for the period under consideration, defined as the difference between the calendar time and the stopping time of the furnace

(Tr

   )

The determination of the growth electrode is under the electrode for each electrode in accordance with formula (1). The value of K is determined by the formula

TO,

iQiOjQiati-I, (7)

100

where Q

wholesale

five

hfakt

0

q, the optimum value of the liter of calcium carbide for a particular furnace, kg / l; the average liter of calcium carbide over the time between corrections,, -kg / l; slope angle of direct dependence of Kj value on liter of calcium carbide.

The straight slope depends on the specific 45 furnace, i.e. from its rated power, design, etc., as well as the value of Q. In addition, the quality of calcium carbide (liter) is determined by empirical formulas depending on the temperature of the calcium carbide to be drained, so at T 1690-1900 ° C it looks like:

50

ggQ (0,291Т - 201,5) + 0,9 (8)

at T 1640-1760 0

Q (0.446T - 470) (0.97-0.95) (9)

513508506

moreover, K 0.97 for the beginning of the range, by author. St. No. 993491, about t of l and h aa K 0.95 to the end of the range at T

1950-2200 ° C

Q. 0.313T - 344.1,

(ten)

From block 22, where equation (1) is implemented, a signal proportional to the actual distance of the electrode beneath enters the comparison unit 23, where it is compared with a signal proportional to the average distance of the electrode beneath coming from the memory block.

In case ifD 0, through the amplifier .14 the error signal enters the regulator through the determination unit 16, the length of the electrode, since g actually shows an error in the determination.

Calcium carbide quality signal is formed in blocks. 17 and 18, in which block 17 measures the temperature of the calcium carbide to be drained, and in block 18 one of the following equations is implemented. It is compared with the specified product quality (275–310 L / kg). In case of deviation from the specified range, the control device 11 of the second (central) phase receives a signal to change the electric mode or charge.

If the adjustment is made for a longer period, for example, a day or more, the displacement of calcium carbide can be taken as actual, and according to empirical formulas (8-10).

 The proposed method for controlling a carbide furnace allows improving the quality of control by more accurately determining the working length of the electrode, the distance of the electrode, under the moment of the transfer, by changing the electrical mode and the dosage of the charge.

The optimal energy technology mode provides a reduction in the specific energy consumption and increases the yield of high-quality calcium carbide, so now the first-grade product yield on carbide furnaces is 5-9%, and the average specific energy consumption is 2700-3000 KW / H. Invention Formula

The method of regulation by melting three-phase three-electrode carbide ne

So, in order to improve the quality of control and reduce the specific energy consumption by increasing the accuracy of determining the length of the electrode and correcting the bypass mode, the consumption of active energy and ampere quadrature hours for each electrode are measured, the actual distance is determined periodically according to the formula

15

n KI

We

where k

di

- constant coefficient g 1 determined by

. on the main auth. d., is the diameter of the electrode; - indicator of inertia;

P is the averaged resistivity of the interelectrode space;

K, 1 + tgCf- - coefficient,

dependent on

100

W

iMt is the average calcium carbonate liter over the integration period;

consumption of active energy of the i-th phase, MWh;

the value of amperquadrat hours i-ro electrode, kA. h;

0

pr-t

-R

- T

etc

integration time, defined as the difference between the calendar time and the time of the furnace, h

g compares it with the average, the distance between the electrode and the value determined during the integration period and, in case of deviation, corrects the bypass mode.

Claims (1)

Claim A method for controlling a fused three-phase three-electrode carbide furnace according to ed. St. No. 993491, due to the fact that, in order to improve the quality of control and reduce the specific energy consumption by increasing the accuracy of determining the electrode length and correcting the bypass mode, the consumption of active energy and ampere-square hours for each electrode is measured, periodically determined actual electrode distance - under the formula - a constant coefficient determined by the main auth. d ₉ is the diameter of the electrode; [B - an indicator of inertia; p is the average resistivity of the interelectrode space; K, = 1 + tgCf-Q- ^ffl2J ~ Q- coefficient, depending on the average value of the calcium carbide displacement over the integration period; W is the consumption of active ^α 1 energy of the ith phase, MW · h; I ² dt is the magnitude of the ampere-square hours of the i-ro electrode, kA ² , h; ^T in ^{= t} cal ^{- T} CR is the integration time, defined as the difference between the calendar time and the downtime of the furnace, h, compare it with the average, the electrode-under distance value determined during the integration period and, in case of deviation, adjust the bypass mode . /