JPS62111105A - Mixture volume control device - Google Patents

Abstract

PURPOSE:To enable the safe operation of a turbine by installing a device for restraining the supply of a mixture to a turbine and a bypass device for restraining such a volume to the system of a feed water preheater,and providing a bypass device for a boiler with a feed water preheater. CONSTITUTION:Through the compression of a permissible mixture volume signal detected on a signal changeover device 28 with a control signal from a feed water temperature control device 18, the opening of a feed water temperature control valve 19 is limited and mixture volume is restrained. The bypass device 31 of a system for a feed water preheater 5 is operated for restraining the mixture volume. Furthermore, when feed water temperature gives a rise, the bypass device 35 of a boiler 10 with a feed water preheater is actuated to open wide said device 35 and restrain the heat recovery of the last feed water preheater 6. In this way, the safe operation of a turbine can be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hot air amount control device, and is used in a waste heat recovery power generation plant having an air mixture system.

BACKGROUND OF THE INVENTION A system example of a conventional waste heat recovery power generation plant will be explained with reference to FIG.

In FIG. 4, condensate condensed in a condenser 1 is sent to a hot air rasher 3 by a condensate pump 2, where it is mixed with hot water. Thereafter, the feed water is sent by the feed water pump 4 to the feed water preheater 5 and the boiler attached feed water preheater 6 through the feed water distribution valves 7 and 8, where it is heated by the waste heat source, the temperature is adjusted by the temperature difference controller 9, and the temperature is adjusted by the temperature difference controller 9. Water supply control valves 12 and 13 to No. 10 and No. 2 boiler 11
supplied through.

Here, the No. 1 boiler 1O is an example of a boiler having a feed water preheater 6, and the No. 2 boiler 11 is an example of a boiler consisting of only an evaporator section.

Since each boiler is a waste heat recovery type boiler, ~1
It is heated by a waste heat source and generates steam.

These steams are collected in the main steam pipe 14 and passed through the control valve 15.
Air is sent to the turbine 16 through the air, where it does work, enters the condenser 1, and returns to condensate.

When the waste heat recovered as feed water in the feed water preheaters 5 and 6 is obtained in an amount larger than the amount of water required for the boilers 10 and 11, the temperature control valve is activated by the feed water temperature controller 18 provided in the main water supply pipe 17. 19 is opened to introduce hot water into the air mixture flasher 3.

In the mixture flasher 3, hot water is flashed, and the generated steam is mixed into the intermediate stage of the turbine 16 through the mixture stop valve 20, thereby improving the recovery rate of waste heat.

The hot water relief valve 21 is activated when the turbine is started or when the air mixture is stopped.
Excess hot water is released to condenser l.

Problems to be Solved by the Invention In the conventional system, when the turbine 16 shifts to independent speed control operation or when the load becomes low, air-fuel mixture operation becomes impossible, so the air-fuel mixture stop valve 2o and The feed water temperature control valve 19 is closed to stop the air mixture. Then, the hot water relief valve 21 opens to treat the hot water that was being supplied to the air-fuel mixture flasher 3, and the hot water is dumped into the condenser 1. As a result, the condensate system such as the condenser 1 and the condensate pump 2 suddenly has to process a large amount of condensate. For this reason, an excessively large amount of equipment for hot water dumping, which is not normally used, must be installed, resulting in waste. In particular, in a low-temperature waste heat recovery type plant, the amount of hot water dumped may be excessive, resulting in constraints on the plant configuration.

Due to the structure of the turbine, it is not possible to increase the amount of air mixture arbitrarily, so it is necessary to adjust the amount of air mixture according to the turbine load, but there has been no suitable method in the past.

Means for Solving the Problems According to the present invention, a program is set for the allowable air mixture amount according to the turbine operation method and the turbine load, and the amount of hot water (that is, the amount of air mixture steam) to the air mixture 7 rashers is monitored and controlled. A device is installed to suppress excessive amounts of air mixture.

When air mixture suppression is activated, the set temperature of the hot water release control is temporarily changed to limit excessive hot water dumping.

In addition, monitor the water supply temperature, and if the water temperature rises too much,
A bypass adjustment device that temporarily bypasses the waste heat source of the waste heat boiler is activated to temporarily suppress heat recovery from the low-temperature heat source.

The allowable air-fuel mixture amount during turbine independent speed control operation or normal turbine operation is calculated according to the turbine load, and the allowable air-air air amount is set in a program according to the turbine operating method. On the other hand, the amount of air-fuel mixture vapor is estimated from the amount of hot water at the inlet of the air-fuel mixture flasher, and is compared and monitored with the allowable amount of air-air mixture. If the amount of hot water (that is, the actual amount of air-fuel mixture and steam) becomes excessive, the opening degree of the hot water control valve is controlled. This prevents the turbine from containing more steam than the allowable amount of steam, so the safety of the turbine can be ensured.

When the suppression of the amount of air mixture is activated, the amount of hot water released increases, so the set value of the feed water temperature control is temporarily increased to minimize the opening of the hot water release valve. This eliminates the waste of discharging the recovered waste heat to the condenser and prevents an excessive load on the condensate system.

Even with the above, there is still a risk that the supply water temperature may rise excessively due to an imbalance between the amount of waste heat heating and the amount of recovered heat, so monitor the water supply temperature, and if the temperature of the water supply rises excessively, install a bypass device for the waste heat source. Open it to reduce the amount of waste heat recovered and balance it. At this time, first, the low-temperature waste heat source of the feed water preheater whose main purpose is to generate hot water is bypassed, and if necessary, the waste heat source of the feed water preheater attached to the boiler is bypassed.

This allows the turbine to generate the necessary power, while
Only the mixed steam that must be suppressed for turbine operation can be suppressed, and the amount of hot water released to the condenser can be minimized. This naturally prevents an excessive load on the condensate system, making it unnecessary to install excessive equipment.

Embodiment FIG. 1 shows an example of a waste heat recovery power generation plant to which a device according to the present invention is applied.
is the condensate pump, 3 is the air mixture 7 lacquer, 4 is the water supply pump,
5 is a feed water preheater, 6 is a feed water preheater attached to the die 2, 7 and 8 are feed water distribution valves, 9 is a temperature difference controller, 10 is a boiler with a feed water preheater, 11 is a point 2, 12 and 13 are feed water control valves , 14 is a main steam pipe, 15 is a control valve, 16 is a turbine, 1
7' is a main water supply pipe, 18 is a feed water temperature controller, 19 is a feed water temperature control valve, 20 is an air mixture stop valve, 21 is a hot water relief valve, 22 is a main steam pressure controller, 23 is a generator, 24 is a Generator output meter, 25 is a program setting device for normal operation, 26 is a program setting device for independent speed control operation, 27 is an independent operation detector, 28
is a signal switch, 29 is a low signal selector, 30 is a signal switch, 31 is a feed water preheater bypass device, 32 is a temperature setting device, 33 is a temperature detector, 34 is an override relay, 35
indicate bypass devices, respectively.

The condensate condensed in the condenser 1 is sent to an air-fuel mixture flasher 3 by a condensate pump 2, where it is mixed with hot water.

Thereafter, the feedwater pump 4 sends the feedwater to a feedwater preheater 5 and a boiler attached feedwater preheater 6 through feedwater distribution valves 7 and 8, where it is heated by a waste heat source and heated by a temperature difference controller 9.
The temperature of the water is adjusted by , and the water is supplied to No. 1 boiler 10 and No. 2 boiler 11 through feed water control valves 12 and 13 .

The No. 1 boiler 10 is an example of a boiler having a feed water preheater 6, and the No. 2 boiler 11 is an example of a boiler consisting of only an evaporation section.

Each boiler is heated by a waste heat source (not shown) and generates steam. These steams are collected in the main steam pipe 14,
Air is sent to the turbine 16 through the control valve 15, where it does work, enters the condenser 1, and returns to condensate. When the waste heat recovered as feed water in the feed water preheaters 5 and 6 is obtained in an amount larger than the amount of water required for the boilers 10 and 11, the temperature control valve is activated by the feed water temperature controller 18 provided in the main water supply pipe 17. 19 is opened and hot water mixture 7 is introduced into the lash 3. In the air-fuel mixture flasher 3, hot water is flushed,
The generated steam is mixed into the intermediate stage of the turbine 16 through the mixture stop valve 2o. This particularly aims to recover low-temperature waste heat and contributes to improving the heat recovery rate.

The hot water release valve 21 releases excess hot water to the condenser 1 when the turbine is started or when the air mixture is stopped.

In such a waste heat recovery plant, in order to effectively utilize the heat recovered by the feed water preheater 5.6 and the boilers 10, 11, the main steam pressure controller 22 usually installed in the main steam pipe 14
Accordingly, the control valve 15 is controlled to effectively introduce the generated steam amount to the turbine 16.

So-called front pressure control operation is being performed.

When the turbine 16 shifts to independent speed control operation due to some circumstances, the amount of air-fuel mixture is limited due to the need to ensure the speed control function of the turbine 16. Furthermore, in order to ensure safe operation of the turbine 16, the amount of air mixture depends on the turbine load, and the amount of air mixture cannot be increased blindly.

Therefore, the load on the turbine 16 is measured as the output of the generator 23 by the generator output meter 24, and the allowable air mixture amount is calculated and set by the program setting devices 25 and 26 in accordance with this turbine output. The setter 25 sets the allowable air mixture amount during normal operation, and the setter 26 sets the allowable air mixture amount during independent speed control operation. An example of the log system settings is shown in FIG. An individual operation detector 27 detects whether the turbine 16 and the generator 23 are operating in parallel or individually, and the signal switch 28 is activated to select the setting device 26 or 27. The selected allowable air mixture amount signal and the control signal from the feed water temperature controller 18 are monitored by the low signal selector 291C, and when a temperature signal exceeding the allowable air mixture amount signal is transmitted, the allowable air mixture amount signal is immediately detected. The air amount signal is selected, the opening degree of the feed water temperature control valve 19 is limited, and the amount of hot water (that is, the amount of air mixture) is suppressed.

Suppressing only the air mixture amount will cause a rise in the feed water temperature, so when the independent operation detector 27 detects the independent speed control operation, the signal switch 30 is also operated at the same time, and the bypass device 31 is set to the allowable air mixture amount signal. Open to the appropriate opening degree to suppress the amount of waste heat recovery. At this time, it is important to first operate the bypass device 31 of the feed water preheater 5 system, whose main purpose is to generate hot water, to suppress the amount of air mixture. Furthermore, the recovered waste heat passes through the hot water relief valve 21 to the condenser 1.
In order to prevent the water from being released to the boiler, the temperature setter 32 of the feed water temperature controller 18 is activated at the same time as the signal switch 3o is switched, and the set temperature is increased to the upper limit temperature allowed by the boiler 11 and 12. let If the feed water temperature rises even after operating these, the temperature detector 33Fc detects an excessive rise in the feed water temperature, and after confirming that the island operation detector 27 detects the island control operation, The override relay 34 is activated to drive the bypass device 35 of the boiler 10 with a feed water preheater, and the bypass device 35 is fully opened.
Heat recovery in the last feed water preheater 6 is suppressed.

Thereby, the amount of air mixture can be suppressed according to the operating system and load of the turbine 16 and the generator 23, and the release of hot water to the condenser 1 can be suppressed to a minimum. Therefore, safe operation of the turbine 16 can be ensured, and there is no need to increase the installed capacity of the condensate system.

The bypass devices 31 and 35 will be specifically explained with reference to FIGS. 3A to 3C, taking as an example the case where the waste heat source is waste gas.

The bypass device 31 of the feed water preheater 5 is as shown in FIG. 3a,
It has a bypass duct 311 and a bypass damper 312 provided therein, and a ventilator 51 is installed downstream of the water supply preheater 5.
It is preferable that the bypass damper 312 is opened and the inlet damper 52 is closed when the feed water temperature rises excessively.

3b and 3c show examples of the bypass device 35 for the boiler 10 with a feed water preheater, in which the boiler 10 is bypassed by a bypass duct 351 and a bypass damper 352 installed therein; The figure shows an example in which only the boiler attached water preheater 6 is bypassed by a bypass duct 353 and a bypass damper 354. When the supply water temperature rises excessively, the bypass damper 352
Open the ventilator artificial damper 101 or close the bypass duct 35 of the boiler attached water supply preheater 6.
It is desirable to open the bypass damper 354 provided at 3.

In addition to the effects of the invention, according to the present invention, the following effects can be achieved.

(al) By monitoring, comparing, and suppressing the allowable air mixture amount and feed water temperature control signal according to the turbine operation method and turbine load, the amount of steam flowing into the turbine can be suppressed to below the allowable limit of the turbine. , safe operation of the turbine can be ensured.

(bl) At the same time, by changing the set temperature of the feed water temperature controller to the boiler's upper limit temperature and by activating the bypass device of the feed water preheater first, the release of hot water to the condenser can be minimized. Since it can be suppressed, there is no need to release waste heat that has been recovered to the condenser.

(By installing a temperature detector on the C1 water supply pipe and activating the bypass device of the feed water preheater attached to the boiler when the feed water temperature rises excessively, it is possible to suppress the recovery of waste heat. It is possible to prevent wasteful release.

(d) By following the above steps, in the unlikely event that the amount of air mixture in the turbine is limited, only the air mixture can be restricted without securing main steam to the turbine, and hot water to the condenser can be restricted. Since sudden discharge does not occur, there is no need to increase the installed capacity of the condensate system to accommodate hot water discharge.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a waste heat recovery power generation plant showing an example in which the control device according to the present invention is applied; FIG. 2 is a diagram showing an example of program setting of allowable air mixture amount according to turbine operation method and turbine load; 3a, 3b, and 3c are diagrams showing examples of a bypass device when the waste heat source is waste gas, and FIG. 4 is a system diagram of a conventional waste heat recovery power generation plant. 1. Condenser, 2. Condensate pump, 3. Air mixture 7 lacquer, 4. Water supply pump, 5. Water supply preheater, 6. Water supply preheater attached to boiler, 7, 8. Water supply. Distribution valve, 9. Temperature difference controller, 10. Boiler with feed water preheater, 11. Boiler, 12, 13. Fist water supply control valve, 14. Main steam pipe, 1
5. Adjustment valve, 16. Fist turbine, 17. Main water supply 'I
, 18. Φ Feed water temperature controller, 19.. Feed water temperature control valve, 20.. Air mixture stop valve, 21.. Hot water relief valve, 22.. Main steam pressure controller, 23.. Generator, 24. - Generator output meter, 25.. Program setting device for normal operation, 26.. Program setting device for independent speed control operation, 27.. Independent operation detector, 28.. Signal switching device, 29.. Low signal selector. , 30
...Signal switching device, 31..Bypass device for water supply preheater,
32...Temperature setting device, 33...Temperature detector, 34...Override relay, 35...Bypass device. (1 other person)

Claims (1)

[Claims] A program setting device that calculates and sets an allowable air mixture amount signal according to the turbine operation method and turbine load, and compares the allowable air mixture amount signal with the feed water temperature control signal to reduce the amount of steam to the turbine below the allowable limit. a bypass device installed in the feed water preheater to suppress the amount of heat recovery in the event of an excessive rise in the feed water temperature; and a bypass device installed in the feed water preheater attached to the boiler to suppress the amount of heat recovery in the event of a further increase in the feed water temperature. An air-fuel mixture control device comprising a bypass device for suppressing the amount of air.