JPH03146786A - Controller for steam flow rate in occurrence of web break in papermaking machine in boiler equipment - Google Patents

Abstract

PURPOSE:To enable stable operation of a steam boiler even if web break occurs in a papermaking machine by regulating a control valve for bypassing part of steam in a feed pipe to a specific opening degree. CONSTITUTION:When a changeover device 18 is changed over on a web break signal (VC) of a papermaking machine, steam flow rate sensed with a flow rate sensor 17 in the moment as the standard steam flow rate (QM) is held in a memory 19. The deviation (DELTAQO) of the subsequent steam flow rate (QO) from the flow rate (QM) is multiplied by a prescribed ratio (K) to provide a command (KO) of opening degree determination. A command (VS1) of the opening degree corresponding to the command (KO) is outputted from a function producer 24 to a control valve 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a steam flow rate control device when a paper breakage occurs in a paper manufacturing machine in a boiler facility.

[Prior Art] In paper making machines, steam generated in a steam boiler is sprayed onto the front and back surfaces of paper during the papermaking stage in order to adjust the quality of the paper.

Therefore, in a paper machine, when a paper break occurs, the valve installed in the steam system of the paper machine where the paper break occurs is closed,
This is to prevent unnecessary consumption of steam.

However, when a valve is closed, there is no steam consumption in that system, so unless the steam flow rate generated by the steam boiler is reduced, the speed of the steam turbine will increase and the amount of power generated by the generator will increase significantly. Therefore, if paper breaks occur in the papermaking machine, it is necessary to reduce the amount of steam generated in the steam boiler.

[Problem to be solved by the invention] However, if the amount of steam generation is suddenly reduced, it will cause a large disturbance to the steam boiler, and in extreme cases, it may even become impossible to operate the boiler. However, no special measures were taken to prevent such situations, and it was left up to the operators to decide how to operate the machine, so if a paper break occurred in the paper machine, it would be necessary to There was a problem that it could make driving difficult.

The present invention has been made in view of the above-mentioned circumstances, and has an object to enable stable operation of a steam boiler even when paper breaks occur in a paper manufacturing machine.

[Means for Solving the Problems] The present invention provides a steam boiler l and each steam turbine 2 that is driven by the steam from the steam boiler l to drive a generator 3.
, a condenser 11 for condensing the steam exhausted from the steam turbine 2, and a cutoff valve 14-1.14-2.14-3 for at least part of the steam extracted from the steam turbine 2.
．． 14-4 to paper machines M1, M2. M3. In a boiler facility equipped with an air supply pipe 12 that supplies air to the air supply pipe 12 and a bypass pipe 15 that can bypass at least a part of the steam in the air supply pipe 12 to the condenser 11 via a control valve 16, a flow rate detector 17 that detects the steam flow rate QO of the paper-making machine; a switching device 18 that is switched by the paper-making machine paper-out signal vc and causes the memory 19 to self-hold the steam flow mQO at the moment when a paper-out occurs as a reference steam flow rate QM; a subtracter 20 for calculating the deviation JQO between the steam flow rate QO after the occurrence of a paper break from the flow rate detector 17 and the steam flow rate QM from the memory I9; a multiplier 22 that multiplies the deviation ΔQO by a predetermined ratio K; Opening degree determination command KO obtained in 22
The control valve 16 is equipped with a function generator 24 that provides an opening command VSI corresponding to the control valve 16 to the control valve 16.

[Function] When the switch 18 is switched by the paper machine paper out signal Vc, the steam flow rate Q detected by the flow rate detector 17 at that moment
O is self-maintained in the memory 19 as a reference vapor flow mQM, and the subsequent vapor flow ff1 from the flow rate detector 17 is
The deviation ΔQO between the QO and the steam flow rate QM from the memory 19 is determined by a subtracter 20, and the multiplier 22 multiplies the deviation ΔQO determined by the subtracter 20 by a predetermined ratio K to determine the opening degree determination command KO. An opening command VSI corresponding to the opening determination command KO is output from the function generator 24 and applied to the control valve 16, and the control valve 16 is adjusted to a predetermined opening. For this reason, a part of the vaporized sludge in the air supply pipe 12 is bypassed to the condenser 11 through the bypass pipe 15 and the control valve 16. Therefore, the paper machines M1, M2. M
3. Any shutoff valve 14-1.14-2.14- of M4
Even if 3.14-4 is closed, the load adjustment of the steam boiler 1 can be performed slowly, and stable operation of the steam boiler 1 is possible.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention, in which 1 is a steam boiler, 2 is a steam turbine, 3 is a generator driven by the steam turbine 2, and 4 is a supply of steam S generated in the steam boiler 1 to the steam turbine 2. 5 is a control valve provided on the steam turbine 2 intake side of the steam pipe 4; 6 is a control valve that controls the flow rate of steam introduced from the extraction side 2a to the exhaust side 2b of the steam turbine 2; 7 is a steam pipe; A bleed pipe 8 is connected to the bleed port 2C of the turbine 2, a bypass pipe 8 is connected to connect the steam pipe 4 and the bleed pipe 7 and is equipped with a control valve 9 in the middle part, and lO is a υ" of the steam turbine 2. An exhaust pipe connected to the air port 2d, 11 a condenser installed in the exhaust pipe IO to condense the steam exhausted from the steam turbine 2 and return it to water, and 12 a condenser that is sent from the extraction pipe 7. Air supply pipe that sends steam, 13-1.13
-2°13-3, 13-4 branches from the air supply pipe 12, and each paper making machine M1, M2. M3. The air supply pipe that supplies steam to M4, 14-1.14-2.14-3.14-4 is the cutoff valve provided in the air supply pipes 13-1.13-2, 13-3 and 13-4, and 15 is the It is a bypass pipe connected to the air supply pipe 12 at one end and the condenser 11 at the other end, and equipped with a control valve 16 in the middle.

17 is a flow rate detector connected to the downstream side of the bypass pipe 15 connection part of the air supply pipe 12 in the steam flow direction; 18 is a paper making machine M1, M2 . M3. When a paper break occurs in any of M4, the switch is made by the paper machine paper break signal Vc, and the steam flow rate QO detected by the flow rate detector 17 when receiving the paper machine paper break signal Vc is set as the reference steam flow rate QM in the memory 19. 20 calculates the deviation ΔQO between the steam flow rate QM from the memory 19 and the steam flow rate QO sent from the flow rate detector 17 without passing through the switch 18 and the memory 19. It is a subtractor.

22 is a multiplier that multiplies the deviation JQO from the subtracter 20 by the ratio K set by the ratio setter 23 to obtain the opening determination command KO; 24 is the opening corresponding to the opening determination command Ko from the multiplier 22; A function generator outputs the command '/Sl and supplies it to the control valve 16 via the automatic manual switch 25. A function generator 26 is a subtractor for calculating the deviation ΔQO from the subtracter 20 and the deviation AQI between the opening determination command KO from the multiplier 22. 27 is the subtractor 26
This is a control device that processes the deviation AQ■ from the control valves 5 and 6 and provides an opening command VS2VSa to the control valves 5 and 6.

Note that 28 is another mechanical system in which the extracted steam is consumed.

Steam S generated in the steam boiler 1 is introduced from the steam pipe 4 to the oil side 2a of the steam turbine 2 to drive the steam turbine 2, and the steam turbine 2 drives the generator 3. Part of the steam introduced into the bleed side 2a of the steam turbine 2 is extracted into the bleed pipe 7, and the remaining steam is introduced into the exhaust side 2b of the steam turbine 2 through the control valve 6. The water then drives the steam turbine 2 and is discharged to the exhaust pipe lO, is condensed in the condenser 11, returns to water, and is returned to the steam boiler lO.
Water is supplied to

On the other hand, the extracted steam is transferred from the air supply pipe 12 to the air supply pipe 13-
1.13-2.13-3.1: (-4 to paper machine M
l.

M2. M3. It is supplied to M4 and used for paper production,
Alternatively, it is sent to another mechanical system 28 and consumed.

The steam flow rate QO in the air supply pipe 12 is detected by a flow rate detector 17, passes through a switch 18 and a memory 19, and is given to a subtracter 20. , the deviation ΔQO is zero, so no signal is output from the subtracter 20. Therefore, the multiplier 22 does not output the opening determination command Ko, and the function generator 24 does not output the opening command VSI. Therefore, the control valve I6 is closed, and steam does not bypass from the air supply pipe 12 to the condenser 11.

Furthermore, since both the deviation ΔQO and the opening determination command KO are zero, the deviation AQ■ is not output from the subtractor 2B, and therefore the control valves 5 and 6 are controlled by the central controller and the controller 27 (not shown). Opening command given via vs 2 s V
In S3, the output shaft of the steam turbine 2 reaches a predetermined rotation speed, and control is performed so that the electric power generated by the generator 3 becomes a predetermined electric power.

Paper making machines M1, M2. M3. When a paper break occurs in any of the M4s, the paper that was being fed continuously runs out of paper in the paper machine where the paper break occurred, and the light emitted from the phototube emitter is received by the light receiver, which causes the paper machine to break the paper. The signal Vc is applied to the switch 18, and the switch 18 switches. When the switch 18 is switched, the steam flow rate QO at that moment is self-maintained and stored in the memory 19.
The reference steam flow ffiQM is stored as the reference steam flow ffiQM, and the steam flow EtQM is supplied from the memory 19 to the subtractor 20.

On the other hand, the paper-making machine paper-out signal Vc indicates the paper-making machines M1, M2, . M3. M4 shutoff valve 14-1.14-
2.14-3.14-4 and the corresponding isolation valve 1
4-1.14-2.14-3.14-4 are blocked.

Therefore, the flow rate of steam extracted from the extraction side 2a of the steam turbine 2 to the bleed pipe 7 decreases, and the flow rate QO of steam in the air supply pipe 12 also decreases.

The steam flow rate QO detected by the flow rate detector 17 after the switching device 18 is switched is not given to the switching device 18 side because the switching device 18 is switched, but is given only to the subtractor 20. 20, the deviation ΔQO between the reference steam flow rate QM and the detected steam flow ff1QO is ΔQO=Q
The deviation ΔQO is obtained by M-QO and is output from the subtracter 20 and given to the multiplier 22 and the subtracter 26.

Since the multiplier 22 has the ratio K set in advance by the ratio setter 23, the multiplier 22 receives the opening determination command K.
O is determined by -ΔQO to K□-, and the opening degree determination command KO is given to the function generator 24 and the subtractor 26.

For example, the ratio may be determined experimentally in advance during a test run, so that even if paper runs out, the power generated by the generator 3 is within a predetermined range and the boiler load change is at a speed that can be followed by the steam boiler l. Find it empirically.

In the function generator 24, an opening command VS+ of a magnitude corresponding to the opening determination command KO is determined by a function F (x),
The opening degree command VSI is outputted from the function generator 24 and given to the control valve 16 via the automatic/manual switching device 25, so that the control valve 16 is opened to a predetermined opening degree. For this reason, the air supply pipe 12
A part of the steam flows from the bypass pipe 15 through the control valve 16 to the condenser 11, condenses and returns to water, is exhausted from the exhaust side 2b of the steam turbine 2, and is condensed in the condenser 11. Return to the steam boiler l together with the water. The function F (X) is
If the opening determination command KO is large, the opening command VSI will be large, and if the opening determination command KO is small, the opening command VSI will be
It is a linear function such that the value becomes small, and this is also determined experimentally and empirically in advance during a trial run.

In the subtracter 26, the deviation ΔQO from the subtracter 20 and the deviation AQ+ of the opening degree determination command KO from the multiplier 22 are equal to AQ+
−ΔQO−Ko, and the deviation AQ+ is given to the control device 27. Then, the control device 27 outputs the deviation AQ! Based on the command from the central processing unit, a predetermined function command VS21VS3 is given to the control valve 5.6, the rotation speed of the output shaft of the steam turbine 2 falls within a predetermined range, and the electric power generated by the generator 3 increases. Control is performed to keep it within a predetermined range.

As mentioned above, paper making machines M1, M2 . If a paper break occurs in either M3 or M4, part of the steam supplied to the paper making machine can be bypassed to the condenser 11, so the load on the steam boiler I can be gradually changed. Therefore, the steam boiler I can be operated stably.

In the embodiment of the present invention, when a paper break occurs, the opening degrees of the control valve 5 of the steam pipe 4 and the control valve 6 of the steam turbine 2 in addition to the control valve 16 of the bypass pipe 15 are adjusted. As described above, if there is no problem even if the amount of fluctuation in the electric power generated by the generator 3 is large, the control valve 5.
6 may be controlled, paper making machines M1, M2 . M
It goes without saying that any number of 3°M4 units can be applied, and that various other changes can be made without departing from the gist of the present invention.

[Effects of the Invention] In the steam flow rate control device when paper breakage occurs in a paper making machine in a boiler equipment of the present invention, the steam flow rate control device when paper breakage occurs in a paper making machine Ml.

M2. M3. If any paper breaks on M4,
Since a part of the steam supplied to the paper making machine can be bypassed to the condenser 11, it is possible to gradually change the load on the steam boiler 1, and therefore the steam boiler 1 can be operated stably. This can produce excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an embodiment of the present invention. In the figure, l is a steam boiler, 2 is a steam turbine, 3 is a generator,
4 is a steam pipe, 5.6 is a control valve, 7 is a bleed pipe, 10 is an exhaust pipe, 11 is a condenser, 12.13-1, 13-2゜13
-3.13-4 is air supply pipe, 14-1.14-2.14-
3.14-4 is a shutoff valve, 15 is a bypass pipe, 16 is a control valve, 17 is a flow rate detector, 18 is a switch, 19 is a memory, 20 is a subtracter, 22 is a multiplier, 23 is a ratio setter, 2
4 is a function generator, M1, M2 . M3. M4 is a paper making machine,
QO, QM are steam flow rates, JQO, AQI are deviations, K is ratio, KO is opening determination command, Vc is paper machine paper out signal,
VS+, VS2, and VS3 indicate opening commands.

Claims (1)

[Claims] 1) A steam boiler 1, each steam turbine 2 that is driven by the steam from the steam boiler 1 to drive the generator 3, a condenser 11 that condenses the steam exhausted from the steam turbine 2, and the steam At least a portion of the steam extracted from the turbine 2 is supplied to the cutoff valves 14-1, 14-2, 14-3, 14.
- an air supply pipe 12 supplying the paper making machines M1, M2, M3, M4 via a bypass through which at least a part of the steam in said air supply pipe 12 can be bypassed via a control valve 16 to said condenser 11; In the boiler equipment equipped with the pipe 15, the air supply pipe 1
a flow rate detector 17 that detects the steam flow rate Q_O in the paper machine 2, and a switching device 18 that is switched by the paper machine paper breakage signal V_C and self-holds the steam flow rate Q_O at the moment when paper breakage occurs in the memory 19 as the reference steam flow rate Q_M. , a subtractor 20 for calculating the deviation ΔQ_O between the steam flow rate Q_O after the occurrence of paper breakage from the flow rate detector 17 and the steam flow rate Q_M from the memory 19; a multiplier 22 that multiplies the deviation ΔQ_O by a predetermined ratio K; Steam flow rate when a paper-making machine runs out of paper in a boiler facility characterized by comprising a function generator 24 that provides the control valve 16 with an opening command V_S_1 corresponding to the opening determination command K_O obtained by a multiplier 22 Control device.