JP4895835B2 - Steam recovery equipment - Google Patents

Description

The present invention is effectively vapor recovery set Bei relates to heat recovery steam return used to heat the feed water to the boiler in power plants.

  In power generation facilities such as a thermal power plant, generated high-temperature and high-pressure steam is supplied to a turbine, and the turbine is driven by this steam to generate power. The steam after driving the turbine is condensed by the condenser to be condensed water, and the condensed water condensed by the condenser is deaerated by the deaerator. After that, the condensate deaerated by the deaerator is heated by steam and heated to be supplied to the boiler.

  The feed water sent to the boiler is heated by high-pressure heat exchange means by high-temperature and high-pressure steam extracted from a high-pressure turbine. Further, the return of the steam used for heating the feed water is directly put into the tank of the deaerator by the steam pressure of the turbine bleed air, and the heat energy of the steam is recovered in the tank. On the other hand, the condensate condensed in the condenser is indirectly heated by the indirect heat exchange means by the low-temperature and low-pressure steam extracted from the low-pressure turbine. When the pressure of the steam extracted from the turbine decreases when the power generation facility is started, the return of steam used for heating the feed water is sent to an indirect heat exchange means for heating the condensate.

  The power generation equipment generally has a building structure (see, for example, Patent Document 1), and high-pressure heat exchange means for heating the feed water deaerated by the deaerator and condensate condensed by the condenser. The deaerator is installed at a high position with respect to the indirect heat exchange means for heating. Although the deaerator is installed at a high position, when the pressure of the steam extracted from the turbine is sufficiently high, the pressure of the turbine extraction is high and pushes the return of the steam. The return of steam is pumped to the deaerator. On the other hand, when the pressure of the steam extracted from the turbine decreases, such as when power generation equipment is started, the pressure of the extracted air is low and the pressure of the steam of the high-pressure heat exchange means decreases. The force to push the steam back into the vessel is weakened. Therefore, the return of steam is caused to flow from the high pressure heat exchange means to the indirect heat exchange means installed at the same height.

  The temperature of the steam used for heating the feed water by the high-pressure heat exchange means for heating the feed water deaerated by the deaerator is, for example, a high temperature exceeding 120 ° C, whereas the condensed water condensed by the condenser is used. The temperature of the steam of the indirect heat exchange means for heating water is, for example, about 100 ° C. Therefore, high-temperature steam exceeding 120 ° C., for example, is pumped to the deaerator tank that maintains a temperature close to 120 ° C. by the high-pressure heat exchanging means. Return heat energy is recovered.

  However, when the pressure of the turbine bleed, such as in a low load operation, is reduced, the return of high-temperature steam exceeding 120 ° C., for example, is sent to the indirect heat exchange means having only 100 ° C., for example. For this reason, the loss of heat energy of the steam becomes large. In this way, when the pressure of the turbine bleed air drops and does not reach a sufficient steam pressure to pump from the high pressure heat exchange means to the deaerator, the return of the hot steam used to heat the feedwater is similarly Since it is sent to the low-temperature indirect heat exchange means rather than the deaerator that maintains the high temperature, there is a problem that the thermal energy of the steam is not sufficiently recovered.

JP-A-9-236209

The present invention has been made in view of the above situation, and when the pressure of steam extracted in a low-load operation of the power generation facility is reduced, the heat energy of returning steam used for heating the feed water is effectively recovered. , and to provide a vapor recovery equipment which can improve the efficiency of power generation equipment

In order to achieve the above object, a first aspect of the present invention includes a turbine driven by steam from a boiler, a condenser for condensing steam that has finished work in the turbine, and a condenser condensed by the condenser. A deaerator that degasses the water to supply water, a condensate supply pump that pumps the condensate condensed in the condenser to the deaerator, and a boiler that supplies the water degassed by the deaerator This is a power generation facility equipped with a feed water pump for pumping and high pressure heat exchange means for heating the feed water pumped to the boiler with high pressure steam, and degass the return of steam as the heat medium of the high pressure heat exchange means A drain path to be sent to the vessel, a pressure feed pump that applies pressure to supply steam to the deaerator when the pressure of the steam flowing through the drain path is reduced, an adjustment valve that opens and closes the drain path, and an adjustment valve If the amount of steam in the high-pressure heat exchange means exceeds the specified amount on the condition that the In the vapor recovery system, characterized in that a control means for driving the pressure pump to.

In the first aspect, when the pressure of the supplied steam is reduced, the steam is sent from the high-pressure heat exchange means to the deaerator by the pump, so that the heat of the steam used for heating the feed water is effectively used. It can be recovered.
Furthermore, when the pressure of the steam to be fed is lowered, the steam can be pumped from the high pressure heat exchanging means to the deaerator by driving the pressure pump while adjusting the amount of steam with the regulating valve.

  According to a second aspect of the present invention, in the steam recovery facility according to the first aspect, the power generation facility is provided with indirect heat exchange means for heating the condensate fed to the deaerator with low-pressure steam. The steam recovery facility is characterized by comprising a drain pipe branched from the drain path for sending a return of steam, which is used as a heat medium of the high-pressure heat exchange means, to the indirect heat exchange means as a heat medium.

  In the second aspect, when the pressure of the supplied steam is reduced, such as when the power generation facility is started, the return of the steam can be caused to flow from the high-pressure heat exchange means to the indirect heat exchange means.

According to a third aspect of the present invention, in the steam recovery facility according to the first or second aspect, the deaerator of the power generation facility is installed at a position higher than the high pressure heat exchange means, and the high pressure heat exchange of the power generation facility is performed. The steam recovery facility is characterized in that steam extracted from the turbine is sent as a heat medium.

In the third aspect, when the operating load of the power generation facility is high and the pressure of the steam extracted from the turbine is high, the steam is sent from the high-pressure heat exchange means to the deaerator installed at a high position by the steam pressure. It is done.

According to a fourth aspect of the present invention, a turbine driven by steam from a boiler, a condenser that condenses steam that has finished work in the turbine, and degassed condensate condensed in the condenser. A deaerator that supplies water, a condensate supply pump that pumps condensate condensed in the condenser to the deaerator, and condensate that is pumped to the deaerator are added by steam extracted from the low-pressure turbine. Indirect heat exchange means for heating, feed water pump that pumps feed water deaerated by the deaerator, and feed water that is installed at a lower position than the deaerator and pumped to the boiler is extracted from the high-pressure turbine Power generation equipment comprising high-pressure heat exchange means for heating by the heated steam and an extraction passage for sending steam extracted from the high-pressure side turbine to the high-pressure heat exchange means, and steam used as a heat medium for the high-pressure heat exchange means Drain path that pumps return of air to deaerator by bleed pressure A drain pipe that branches off from the drain path and is used as a heat medium for the high-pressure heat exchange means, and a drain pipe that sends the return to the indirect heat exchange means as a heat medium; When the amount of steam in the high-pressure heat exchanging means exceeds the specified amount, provided that the pump for applying pressure to feed the deaerator, the regulating valve for opening and closing the drain path, and the regulating valve are open And a control means for driving the pressure feed pump.

In the fourth aspect, when the operating load of the power generation facility is low and the pressure of the steam to be fed is lowered, the pump is driven, and the amount of steam is adjusted by the regulating valve and installed at a high position from the high pressure heat exchange means The recovered steam can be fed to the deaerator.

  According to the steam recovery facility and the steam recovery method of the present invention, when the pressure of steam extracted in a low load operation of the power generation facility decreases, the return of steam recovered by the high-pressure heat exchange means is returned to the deaerator. Since it can be pumped, it is possible to effectively recover the heat energy of returning steam used for heating the feed water and improve the efficiency of the power generation equipment.

  FIG. 1 shows a schematic system of a power generation facility provided with a steam recovery facility according to an embodiment of the present invention.

  As shown in the figure, the power generation facility includes a boiler 1 in which fuel f is burned at a high temperature, and the boiler 1 is connected to a turbine through a steam flow path. In the turbine, a high-pressure turbine 2 on a high-pressure side and a low-pressure turbine 3 on a low-pressure side are connected in series. A steam flow path connecting the boiler 1 and the turbine is connected to each of the high-pressure turbine 2 and the low-pressure turbine 3. A generator 4 for generating power is provided on the same axis of the high-pressure turbine 2 and the low-pressure turbine 3 connected in series.

  The low-pressure turbine 3 is provided with a condenser 5 that condenses steam to be condensed. A condenser pump 6 is provided on the outlet side of the condenser 5 provided in the low-pressure turbine 3, and the condenser 5 and the low-pressure feed water heaters 7 </ b> A to 7 </ b> C (indirect heat exchange means) Are connected to the low-pressure feed water heaters 7A and 7B. The low-pressure feed water heaters 7A to 7C are configured by low-pressure feed water heaters 7A and 7B connected in parallel and a low-pressure feed water heater 7C that heats the condensate heated by the low-pressure feed water heaters 7A and 7B.

  A condensate booster pump 10 is provided on the outlet side of the low-pressure feed water heater 7C. The low pressure feed water heater 7C and the deaerator 11 positioned above the low pressure feed water heater 7C are connected by a condensate flow passage. Condensate is pumped from the low pressure feed water heater 7 </ b> C to the high deaerator 11 by the condensate booster pump 10. In the deaerator 11, the condensate sent from the condenser 5 is deaerated and supplied as water. On the outlet side of the deaerator 11, a feed water boost pump 12 is provided, and the deaerator 11 and a high-pressure feed water heater 13 </ b> A located below the deaerator 11 are connected by a feed water flow passage. Feed water is pumped from the deaerator 11 at a high place to the high pressure feed water heater 13A by the feed water booster pump 12. The high-pressure feed water heater 13A is installed at the lowermost stage of the high-pressure feed water heater 13 (high-pressure heat exchange means) consisting of multiple stages (for example, four stages) in the vertical direction. In the high-pressure feed water heater 13, a high-pressure feed water heater 13B, a high-pressure feed water heater 13C, and an uppermost high-pressure feed water heater 13D are connected by a feed water flow path in order from the lowermost high-pressure feed water heater 13A. . The high-pressure feed water heater 13D installed at the uppermost stage of the multi-stage high-pressure feed water heater 13 and the boiler 1 are connected by a feed water flow passage.

  As described above, steam is generated from the boiler 1, steam that has worked in the turbine is converted into condensate by the condenser 5, the condensate is heated by the low-pressure feed water heaters 7 </ b> A to 7 </ b> C, and is recovered by the deaerator 11. A solid line indicates a process in which the water is deaerated and then heated by the high-pressure feed water heater 13 and supplied to the boiler 1.

  Generally, in a power generation facility, each device is arranged in a multi-storey building structure. The deaerator 11 is installed on the upper floor of the building, and the low-pressure feed water heaters 7A to 7C on the upstream side of the deaerator 11 and the high-pressure feed water heater 13 on the downstream side of the deaerator 11 are located on the lower floor of the building. Is installed.

  The low-pressure feed water heater 7C and the low-pressure turbine 3 are connected by a first extraction passage 21, and the low-pressure feed water heater 7C and the low-pressure feed water heaters 7A and 7B are connected by a passage for turbine extraction.

  For this reason, the steam extracted from the low-pressure turbine 3 is introduced from the low-pressure feed water heater 7C to the low-pressure feed water heaters 7A and 7B. In the low pressure feed water heaters 7A to 7C, steam introduced into the low pressure feed water heaters 7A to 7C heats the feed water to a desired temperature as a heat medium.

  The uppermost high pressure feed water heater 13 </ b> D of the high pressure feed water heater 13 and the high pressure turbine 2 are connected by a second extraction path 22. In the multi-stage high-pressure feed water heater 13, the high-pressure feed water heater 13 </ b> C, the high-pressure feed water heater 13 </ b> B, and the bottom-stage high-pressure feed water heater 13 </ b> A are arranged from the second extraction path 22 in order from the top high-pressure feed water heater 13 </ b> D. They are connected by an extended turbine bleed passage.

  For this reason, the steam extracted from the high-pressure turbine 2 is introduced from the high-pressure feed water heater 13D to the high-pressure feed water heater 13C, the high-pressure feed water heater 13B, and the high-pressure feed water heater 13A. In the high-pressure feed water heater 13, the steam introduced into the high-pressure feed water heater 13 serves as a heat medium to heat the feed water to a desired temperature, thereby further raising the temperature of the feed water.

  Moreover, the return temperature of the steam in the high-pressure feed water heater 13 </ b> A connected to the high-pressure turbine 2 through the second extraction path 22 is a high temperature exceeding 120 ° C., for example. Similarly, the temperature in the deaerator 11 for degassing the condensate is maintained at a high temperature close to 120 ° C., for example. On the other hand, the temperature of the steam in the low-pressure feed water heater 7 </ b> C connected to the low-pressure turbine 3 through the first extraction path 21 is, for example, about 100 ° C.

  The high pressure feed water heater 13 </ b> A and the deaerator 11 positioned above the high pressure feed water heater 13 </ b> A are connected by a first drain path 18. A first drain path 18 connecting the high-pressure feed water heater 13 </ b> A and the deaerator 11 is provided with a check valve 23 and a first adjustment valve 14 in order. A second drain path 19 is branched from between the check valve 23 and the first adjustment valve 14 on the first drain path 18. The second drain path 19 is provided with a pressurizing pump 17 (pressure feeding pump) and a second regulating valve 15 in this order. The second drain passage 19 is arranged so as to merge from the rear side of the second regulating valve 15 to the rear side of the first regulating valve 14 of the first drain passage 18. The pressurizing pump 17 in the second drain path 19 is for pumping steam from the high pressure feed water heater 13 </ b> A to the deaerator 11 at a high place.

  As described above, the extraction path of the turbine extraction used as the heat medium in the steam recovery facility according to the embodiment of the present invention and the flow path for recovering the heat of returning steam are indicated by dotted lines.

  A high-pressure feed water heater 13 </ b> A on the lower floor of the building and a deaerator 11 on the upper floor of the building are connected by a second drain path 19 including a first drain path 18 and a pressurizing pump 17. For this reason, during high load operation where the pressure of the turbine bleed air is high, the steam of the high pressure feed water heater 13 is pushed up, so the first regulating valve 14 passes from the high pressure feed water heater 13A on the lower floor via the first drain path 18. While the amount of steam is adjusted, the return of steam is directly put into the tank of the deaerator 11 on the upper floor. On the other hand, when the turbine bleed air pressure is low and the load is low, the pressurization pump 17 is driven and the steam of the high-pressure feed water heater 13 is pushed up, so that the second drain path 19 passes from the high-pressure feed water heater 13A on the lower floor. Then, while the amount of steam is adjusted by the second regulating valve 15, the return of steam is put directly into the tank of the deaerator 11 on the upper floor.

  Further, the high pressure feed water heater 13 </ b> A on the lower floor of the building and the low pressure feed water heater 7 </ b> C on the lower floor of the building are connected by a drain pipe 20. The drain pipe 20 is branched from the second regulating valve 15 of the second drain path 19 and connects the high pressure feed water heater 13A and the low pressure feed water heater 7C. The drain pipe 20 is provided with a third adjustment valve 16.

  During normal operation, the third adjustment valve 16 on the drain pipe 20 is always closed. At the time of low load operation such as start-up, the third regulating valve 16 may be opened to return the steam from the high pressure feed water heater 13A to the low pressure feed water heater 7C.

  During high-load operation, the high-pressure feed water heater 13 has a large extraction pressure of the steam to be sent and the steam is pushed up by the deaerator 11 on the upper floor, so that the steam is unlikely to stay in the high-pressure feed water heater 13. However, at the time of low load operation, since the extraction pressure of the steam to be sent is small and the steam cannot be pushed up by the deaerator 11 on the upper floor, the steam stays in the high-pressure feed water heater 13.

  During the low load operation, the high pressure feed water heater 13 has a multi-stage structure in the vertical direction, so that steam begins to stay in the lowermost high pressure feed water heater 13A. As the operating load further decreases, steam stays from the lower stage to the upper stage of the high-pressure feed water heater 13.

  Thus, the amount of steam staying in the high-pressure feed water heater 13 becomes a trigger for the operation load switching control. Therefore, the steam recovery facility is provided with control means 24 for controlling the start / stop of the pressurizing pump 17 according to the operating load and the opening / closing of the first adjustment valve 14 and the second adjustment valve 15. The control means 24 is configured to send a command based on an input value from a detector (not shown) that detects the amount of accumulated steam. That is, the control means 24 reads the input value from the detector that detects the amount of steam staying in the high-pressure feed water heater 13, and the amount of staying steam increases and the input steam amount exceeds a certain rated value. In addition, the pressure pump 17 is driven, the first adjustment valve 14 is closed, and a command for adjusting the opening of the second adjustment valve 15 according to the amount of steam is sent. On the other hand, when the steam does not stay and the input steam amount is less than the rated value, the control unit 24 stops the pressurizing pump 17 and closes the second regulating valve 15 so that the second control valve 15 is closed. 1 Sends a command to adjust the opening of the adjusting valve 14.

  During high load operation where the turbine bleed pressure is high, the steam is pushed up to the deaerator 11 on the upper floor by the high pressure of the bleed steam, so that the steam does not stay in the high-pressure feed water heater 13 and the detected steam amount is Below the rated value. The control means 24 reads that the amount of steam detected by the detector is below the rated value. Then, a command for stopping the pressurizing pump 17 and closing the second adjustment valve 15 is sent from the control means 24, and the first adjustment valve 14 of the first drain path 18 is sent according to the amount of steam from the detector. A command is sent to adjust the opening.

  For this reason, during high load operation, the first regulating valve 14 of the first drain path 18 is opened by the control means 24, the pressurizing pump 17 of the second drain path 19 is stopped, and the second regulating valve 15 is closed. As a result, the steam pressure of the turbine extraction steam is increased and the steam is lifted, so that the steam is sent from the high-pressure feed water heater 13 </ b> A to the tank of the deaerator 11 through the first drain path 18. Further, while the amount of steam is adjusted by the first regulating valve 14 of the first drain path 18 by the control means 24, high-temperature steam is transferred from the high-pressure feed water heater 13A on the lower floor to the tank of the deaerator 11 on the upper floor. Directly pumped.

  During low-load operation where the pressure of the turbine bleed air is low, the pressure of the bleed steam is small and the steam cannot be pushed up by the deaerator 11 on the upper floor, so that the steam stays in the high-pressure feed water heater 13 and the amount of staying steam increases. To do. When the amount of staying steam continues to increase, the amount of steam in the high-pressure feed water heater 13 shows a value greater than the rated value. The control means 24 reads that the amount of steam detected by the detector is larger than the rated value. Then, a command is sent from the control means 24 to drive the pressure pump 17 of the second drain path 19 and to close the first adjustment valve 14 of the first drain path 18. Furthermore, a command is sent to adjust the opening of the second regulating valve 15 in the second drain path 19 in accordance with the amount of steam from the detector.

  For this reason, at the time of low load operation, the pressurizing pump 17 of the second drain path 19 is driven by the control means 24, the second regulating valve 15 is opened, and the first regulating valve 14 of the first drain path 18 is closed. As a result, since the steam is lifted by the pressurizing pump 17, the steam is sent from the high-pressure feed water heater 13 </ b> A to the tank of the deaerator 11 through the second drain path 19. High-temperature steam is pumped from the lower-floor high-pressure feed water heater 13 </ b> A to the tank of the upper-stage deaerator 11 while the amount of steam is adjusted by the second regulating valve 15 of the second drain path 19 by the control means 24. .

  As described above, not only during high load operation but also during low load operation, the pressurizing pump 17 is driven and the steam at 120 ° C. of the high-pressure feed water heater 13A is, for example, at the low-pressure feed heater 7C having only 100 ° C. Since the heat of the high-temperature steam is directly recovered in the tank of the high-temperature deaerator 11 by being directly pumped to the tank of the deaerator 11 that also maintains a temperature close to 120 ° C. Heat energy can be used effectively.

  Thus, when the pressure of the steam extracted from the high pressure turbine 2 is reduced during the low load operation of the power generation equipment, that is, when the amount of steam staying in the high pressure feed water heater 13 exceeds a certain rated value. The pressure pump 17 of the second drain path 19 is driven by the command of the control means 24 and the flow rate is adjusted by the second regulating valve 15, while the high-pressure feed water heater 13 </ b> A on the lower floor is connected to the deaerator 11 on the upper floor. Hot steam can flow directly into the tank. For this reason, heat recovery of high-temperature steam can be performed efficiently, and the thermal efficiency of the power generation facility can be improved.

  However, as described above, during the normal operation, the third adjustment valve 16 of the drain pipe 20 is closed, but the third adjustment valve 16 is opened by the control means 24 at the time of startup or the like, and the high-pressure feed water heater 13A. The steam return flows into the low-pressure feed water heater 7C.

  In this embodiment, the high-pressure turbine 2 and the low-pressure turbine 3 are arranged in series. However, the arrangement of the turbine differs depending on the power generation equipment, and is not limited to the above-described embodiment. For example, low-pressure / medium-pressure / high-pressure turbines or the like may be installed as appropriate according to the power generation equipment.

  In addition, when there are a plurality of power generation facilities, the steam recovery facility can be commonly used in a plurality of horizontally deployed power generation facilities, not limited to one power generation facility.

The present invention can be utilized in the industrial fields of vapor recovery equipment for the heat recovery steam in power plants.

1 is a schematic system diagram of a power generation facility including a steam recovery facility according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Boiler 2 High pressure turbine 3 Low pressure turbine 4 Generator 5 Condenser 6 Condensate pump 7A, 7B, 7C Low pressure feed water heater 10 Condensate booster pump 11 Deaerator 12 Feed water booster pump 13A, 13B, 13C, 13D High pressure feed water Heater 14 First adjustment valve 15 Second adjustment valve 16 Third adjustment valve 17 Pressure pump 18 First drain path 19 Second drain path 20 Drain pipe 21 First extraction path 22 Second extraction path 23 Check valve 24 Control means

Claims (4)

A turbine driven by steam from the boiler;
A condenser that condenses the steam that has finished work in the turbine,
A deaerator for degassing the condensate condensed in the condenser to supply water;
A condensate supply pump for pumping the condensate condensed in the condenser to the deaerator,
A feed water pump for pumping the feed water deaerated by the deaerator to the boiler;
A power generation facility comprising high-pressure heat exchange means for heating the feed water pumped to the boiler with high-pressure steam,
A drain path for sending the return of steam, which is a heat medium of the high-pressure heat exchange means, to the deaerator;
A pressure-feeding pump that applies pressure to supply steam to the deaerator when the pressure of the steam flowing through the drain path decreases ;
An adjustment valve that opens and closes the drain path;
Pumping when the amount of steam in the high-pressure heat exchange means exceeds a predetermined amount on condition that the regulating valve is open
A steam recovery facility comprising a control means for driving a pump . The steam recovery facility according to claim 1,
The power generation facility is equipped with indirect heat exchange means for heating the condensate pumped to the deaerator with low-pressure steam,
A steam recovery facility comprising: a drain pipe branched from a drain path for sending a return of steam as a heat medium of the high-pressure heat exchange means to the indirect heat exchange means as a heat medium. In the steam recovery equipment according to claim 1 or 2 ,
The deaerator of the power generation facility is installed higher than the high-pressure heat exchange means,
Steam recovery equipment, characterized in that steam extracted from the turbine is sent as a heat medium to the high-pressure heat exchanger of the power generation equipment. A turbine driven by steam from the boiler;
A condenser that condenses the steam that has finished work in the turbine,
A deaerator for degassing the condensate condensed in the condenser to supply water;
A condensate supply pump for pumping the condensate condensed in the condenser to the deaerator,
Indirect heat exchange means for heating the condensate pumped to the deaerator with steam extracted from the low-pressure turbine;
A feed water pump for pumping the feed water deaerated by the deaerator to the boiler;
High-pressure heat exchange means for heating the feed water that is installed at a position lower than the deaerator and pumped to the boiler by steam extracted from the high-pressure turbine;
A power generation facility comprising a bleed path for sending steam extracted from a high-pressure turbine to a high-pressure heat exchange means,
A drain path for pumping the return of the steam, which is the heat medium of the high-pressure heat exchange means, to the deaerator by the pressure of the extraction air;
A drain pipe that branches off from the drain path and sends the return of steam as a heat medium of the high-pressure heat exchange means to the indirect heat exchange means as a heat medium;
A pressure-feeding pump that applies pressure for supplying steam that has been heat-recovered to the deaerator when the pressure of the bleed air drops; and
An adjustment valve that opens and closes the drain path;
Steam recovery equipment comprising: control means for driving a pressure pump when the amount of steam in the high-pressure heat exchange means exceeds a predetermined amount on condition that the regulating valve is open.

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