JP4892539B2 - Combined power plant and waste heat recovery boiler - Google Patents

Description

  The present invention relates to a combined power plant and an exhaust heat recovery boiler.

  As one of means for effectively using the thermal energy of the exhaust gas from the gas turbine, there is an exhaust heat recovery boiler (Heat Recovery Steam Generator (hereinafter referred to as HRSG)). For example, HRSG in a combined power plant (combined cycle power plant) that combines gas turbine equipment and steam turbine equipment generates steam to be supplied to the steam turbine equipment from exhaust gas from the gas turbine equipment (Patent Document 1). Etc.).

  By the way, in the gas turbine equipment provided with the HRSG as described above, when the atmospheric temperature becomes high in summer, the exhaust gas temperature at the HRSG outlet (HRSG outlet exhaust gas temperature) decreases, and the exhaust gas temperature discharged from the chimney to the atmosphere. (Smoke protrusion exhaust gas temperature) may decrease. When the exhaust gas temperature at the smoke outlet decreases as described above, the draft force (exhaust force) of the exhaust gas passing through the chimney is weakened.

  Since a predetermined draft force is required, a device for raising the HRSG outlet exhaust gas temperature is required even at high atmospheric temperatures. Conventionally, as a means for avoiding a decrease in the exhaust gas temperature at the HRSG outlet due to an increase in the atmospheric temperature, a method of designing the HRSG under conditions at a high atmospheric temperature has been adopted.

JP 2007-92721 A

  However, in order to avoid a decrease in the HRSG outlet exhaust gas temperature, if the HRSG is designed under conditions at a high atmospheric temperature, the heat recovery at the HRSG is designed when the atmospheric temperature falls, and the HRSG is designed under a condition at a low atmospheric temperature. It will be lower than if you did. Thus, the amount of heat recovered by HRSG decreases, and the thermal efficiency and plant output decrease.

  Although it is conceivable to raise the exhaust gas temperature by heating the exhaust gas from the HRSG separately, in this case, since a heat source is required, the efficiency is reduced, and additional equipment is required, resulting in an increase in cost. .

Further, in order to avoid a decrease in the HRSG outlet exhaust gas temperature (when it is necessary to increase the HRSG outlet exhaust gas temperature), in addition to ensuring a draft of the exhaust gas passing through the chimney, the exhaust gas temperature does not fall below the acid dew point. Or when the vapor in the exhaust gas discharged from the chimney is below the dew point and is prevented from becoming white smoke. Even in these cases, a technique that suppresses a decrease in thermal efficiency and does not require additional equipment such as a heating device is desired.
In addition to the combined power plant, in the exhaust heat recovery boiler that evaporates the heat medium with the exhaust gas from the exhaust heat source, collects the evaporated heat medium in a drum, and supplies the heat medium from the drum to the heat medium utilization facility. A similar problem arises.

  An object of the present invention is to provide a combined power plant and exhaust heat recovery capable of avoiding a decrease in exhaust gas temperature (increasing exhaust gas temperature) without reducing thermal efficiency as much as possible and without providing additional equipment such as a heating device. To provide a boiler.

  In order to achieve the above object, the present invention detects the exhaust gas temperature at the outlet of the exhaust heat recovery boiler in the combined power plant, and supplies the steam from the exhaust heat recovery boiler to the steam turbine when the exhaust gas temperature is lower than the set temperature. The opening degree of the steam control valve or the steam stop valve provided in the steam pipe is reduced. Here, the case where the opening degree of both the steam control valve and the steam stop valve is throttled is included. Further, the steam control valve or the steam stop valve includes a steam combination valve in which the steam control valve and the steam stop valve are integrated.

  In order to achieve the above object, the present invention provides a steam pipe for supplying steam from the exhaust heat recovery boiler to the steam turbine as an operation method for increasing the exhaust gas temperature at the outlet of the exhaust heat recovery boiler of the combined power plant. The opening degree of the obtained steam control valve or steam stop valve is narrowed, and the pressure in the drum of the exhaust heat recovery boiler is adjusted to be high. Here, it is desirable to perform the operation of narrowing the opening of the steam control valve or the steam stop valve when the outlet temperature of the exhaust heat recovery boiler becomes lower than the set temperature.

  Furthermore, in order to achieve the above object, the present invention provides a heat medium supply system for supplying a heat medium from a drum to a heat medium utilization facility and a heat medium utilization system provided in the heat medium supply system. Steam amount adjusting means for adjusting the amount of heat medium supplied to the facility, exhaust gas temperature detecting means for detecting the exhaust gas temperature at the outlet of the exhaust heat recovery boiler, and the detected temperature of the exhaust gas temperature detecting means being equal to or higher than the set temperature And a control device for adjusting the pressure in the drum by the steam amount adjusting means so as to be held.

  In the present invention, when it is desired to raise the exhaust gas temperature to a set temperature or higher, the opening of the steam control valve or the steam stop valve is reduced. When the opening of the steam control valve or steam stop valve is reduced, the amount of steam supplied to the steam turbine decreases and the pressure in the drum of the exhaust heat recovery boiler increases, so the amount of steam generated in the drum decreases. Thereby, since the amount of heat exchange in the exhaust heat recovery boiler is reduced, the temperature of the exhaust gas can be increased. Accordingly, in the present invention, for example, exhaust heat recovery without designing an exhaust heat recovery boiler under conditions at a high atmospheric temperature, that is, without reducing thermal efficiency as much as possible, and without providing additional equipment such as a heating device. A decrease in boiler outlet exhaust gas temperature can be avoided (exhaust heat recovery boiler outlet exhaust gas temperature is increased).

  The same effect can be obtained in an exhaust heat recovery boiler that evaporates the heat medium with the exhaust gas from the exhaust heat source, collects the evaporated heat medium in a drum, and supplies the heat medium from the drum to the heat medium utilization facility. It is done.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view of an exhaust heat recovery boiler facility according to a first embodiment of the present invention.

  The exhaust heat recovery boiler (HRSG) 11 evaporates water (heat medium) with the exhaust gas 30 from the gas turbine of the gas turbine equipment. Water vapor (evaporated heat medium) generated by the HRSG 11 flows through the steam pipe (heat medium supply system) 31 and is supplied to the steam utilization facility. The steam pipe 31 is provided with a steam control valve (steam amount adjusting means) 24 for adjusting the amount of steam flowing through. The steam control valve 24 is operated based on a signal from the control device 17 that receives the output of the exhaust gas temperature detector (exhaust gas temperature detection means) 12 that detects the temperature of the exhaust gas 14 at the outlet of the HRSG 11 (HRSG outlet exhaust gas temperature). The By adjusting the throttle amount of the steam control valve 24 based on the signal from the control device 17, the HRSG outlet exhaust gas temperature is maintained at a set temperature or higher.

  The gas turbine equipment is rotationally driven by a compressor that compresses the sucked air, a combustor that mixes the compressed air and fuel from the compressor to generate combustion gas, and the combustion gas from the combustor. Equipped with a gas turbine. The exhaust gas 30 supplied to the HRSG 11 is discharged from this gas turbine.

  The HRSG 11 includes a drum 13 in which water vapor evaporated by the exhaust gas 30 is collected. A circulation line (not shown) housed in the HRSG 11 is connected to the lower part of the drum 13, and water supplied to the drum 13 is heated by the exhaust gas 30 in the process of passing through this circulation line. It is evaporated and collected as water vapor on the top of the drum 13.

  The steam pipe 31 is connected to the upper part of the drum 13 and supplies steam generated by the HRSG 11 to steam using equipment (heat medium using equipment) that uses power generation or a heat source. When the steam control valve 24 provided in the steam pipe 31 is throttled, the amount of steam supplied to the steam utilization facility decreases and the pressure in the drum 13 increases. That is, the steam control valve 24 in the present embodiment also functions as a pressure adjusting means in the drum 13.

  The detected temperature of the exhaust gas 14 is input from the exhaust gas temperature detector 12 to the control device 17. The control device 17 in the present embodiment adjusts the throttle amount of the steam control valve 14 so that the detected temperature is maintained at the set temperature T1 or more set to ensure the draft force (exhaust force) of the exhaust gas 14. is doing. Note that the control device 17 in the present embodiment is configured so that the exhaust gas 14 is not in a state except when the gas turbine is started and stopped (that is, during rated load operation and partial load operation (hereinafter referred to as “normal operation”)). The temperature shall be controlled.

  Here, the set temperature T1 means that even when the atmospheric temperature rises, when the exhaust gas 14 is released into the atmosphere through the chimney, the diffusion of the air pollutants such as nitrogen oxides is not hindered. Indicates the temperature at which the draft force is secured. That is, if the temperature of the exhaust gas 14 is maintained at the set value T1 or more, even if the atmospheric temperature rises, the temperature difference necessary for generating the draft force is determined between the smoke outlet exhaust gas temperature and the atmospheric temperature. Can be secured.

  In the gas turbine equipment configured as described above, when the atmospheric temperature increases during normal operation, the temperature of the exhaust gas 14 decreases. At this time, when the control device 17 detects that the temperature of the exhaust gas 14 has reached less than the set temperature T <b> 1 from the detected temperature input from the temperature detector 12, an operation signal for narrowing the opening degree is sent to the steam control valve 24. Output. When the opening degree of the steam control valve 24 is throttled by the control device 17 in this way, the amount of water vapor supplied to the steam utilization facility decreases and the pressure in the drum 13 increases, so that the amount of water vapor generated in the drum 13 is reduced. Decrease. Thereby, since the amount of heat exchange in the HRSG 11 decreases, the temperature of the exhaust gas 14 can be raised. And the control apparatus 17 throttles the steam control valve 24 until the temperature of the exhaust gas 14 reaches the set temperature T1 or more while referring to the detected temperature of the temperature detector 12, and holds the temperature of the exhaust gas 14 at T1 or more. . Thereby, even if atmospheric temperature rises, the temperature of the exhaust gas 14 can be raised.

  In the above, a pressure detector (pressure detection means) for detecting the pressure in the drum 13 may be provided separately, and the temperature of the exhaust gas 14 may be adjusted while actually monitoring the pressure in the drum 13. Thus, if the temperature of the exhaust gas 14 is adjusted while monitoring the pressure in the drum 13, the temperature control accuracy of the exhaust gas 14 can be improved.

  Next, the effects of the present embodiment will be described while referring to the problems in the prior art.

  Generally, the higher the temperature when passing through the chimney, the higher the draft smoke of the exhaust gas, and the higher the diffusing power of air pollutants such as nitrogen oxides when released into the atmosphere. However, when the atmospheric temperature is high, such as in summer, the temperature difference (ΔT) between the exhaust gas temperature and the atmospheric temperature becomes small, so that the draft force tends to weaken and the diffusing power of air pollutants tends to weaken.

  Conventionally, in order to ensure the drafting power of exhaust gas at high atmospheric temperature, (1) HRSG is designed under conditions at high atmospheric temperature, or (2) exhaust gas from HRSG has been The company is trying to secure draft power by increasing the exhaust gas temperature at high atmospheric temperature by providing a separate heating device. However, although the exhaust gas temperature control is not necessary in the measure of (1) above, heat recovery in HRSG is insufficient when HRSG is designed under conditions of low atmospheric temperature when the atmospheric temperature decreases. The thermal efficiency may be reduced, and in the measure (2) above, there is a risk that the energy efficiency may be lowered to secure the energy used by the heating device, and additional equipment is required, resulting in cost. Leading up.

  On the other hand, the gas turbine equipment of the present embodiment includes a control device 17 that throttles the steam control valve 24 so that the temperature of the exhaust gas 14 is maintained at the set value temperature T1 or higher. If the steam control valve 24 is throttled in this way, the temperature of the exhaust gas 14 can be increased even at a high atmospheric temperature, so that the draft force of the exhaust gas 14 can be maintained at a certain level or more. Therefore, according to the present embodiment, since the temperature of the exhaust gas 14 is maintained at a certain value or higher even when the atmospheric temperature rises, the draft force of the exhaust gas 14 can be ensured without reducing the thermal efficiency as much as possible. In addition, the present embodiment does not require a special device such as a heating device for the exhaust gas 14 in the HRSG 11, so that not only the energy efficiency does not decrease, but the cost required for remodeling the gas turbine equipment is low. That is also a merit.

  In the above description, the method of adjusting the pressure of the drum 13 so that the temperature of the exhaust gas 14 is maintained at the set temperature T1 or higher has been described. However, from the viewpoint of improving the thermal efficiency in the HRSG 11, the set temperature T1 is The target temperature of the exhaust gas 14 is set, and the pressure of the drum 13 is preferably adjusted so that the temperature of the exhaust gas 14 approaches the target temperature. In this way, since the temperature rise of the exhaust gas 14 can be suppressed to a necessary minimum, a decrease in thermal efficiency in the HRSG 11 can be suppressed. In this case, it is preferable to adjust the throttle amount of the steam control valve 24 using the temperature difference between the temperature detected by the temperature detector 12 and the set temperature T1.

  In the above description, the gas turbine facility is used as an exhaust heat source. However, the present invention can also be applied to a case where exhaust gas is introduced into the HRSG 11 using a diesel engine as an exhaust heat source.

  Further, in the above description, as an example of increasing the exhaust gas temperature, the case of ensuring the draft force of the exhaust gas has been described as an example. However, the present invention can be similarly applied to the case of increasing the exhaust gas temperature. For example, when the exhaust gas temperature is lowered to be below the acid dew point, depending on the fuel used, vapor containing sulfuric acid may be liquefied and attached on the heat transfer tube in the vicinity of the HRSG outlet, causing corrosion of the HRSG heat transfer tube. For this reason, the set temperature T1 is set to a temperature at which the exhaust gas temperature does not fall below the acid dew point, and the exhaust gas temperature is kept above the set temperature. Further, for example, when the exhaust gas temperature becomes low, the vapor in the exhaust gas discharged from the chimney may become the dew point or lower and white smoke may be generated. Depending on the plant, there may be restrictions on the emission of white smoke due to environmental regulations. For this reason, the set temperature T1 is set to a temperature higher than the dew point of the steam, and the exhaust gas temperature is kept above the set temperature.

  Thus, the present invention is widely applicable when it is necessary to avoid a decrease in exhaust gas temperature during normal operation (increase the exhaust gas temperature).

  FIG. 2 is a schematic view of the vicinity of the HRSG in the combined power plant according to the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same part as the previous figure, and description is abbreviate | omitted (the following figure is also the same).

  In the present embodiment, the steam generated by the HRSG 11 is supplied to the steam turbine of the steam turbine equipment via the steam pipe 31A, thereby constituting a combined power plant combining the gas turbine equipment and the steam turbine equipment. It is different from that of the first embodiment.

  The combined power plant shown in FIG. 2 includes a steam pipe 31A for supplying steam to steam turbine equipment (not shown), and a steam control valve 16 for adjusting the amount of steam supplied to the steam turbine in the steam turbine equipment. And a steam stop valve 15 for stopping the supply of water vapor to the steam turbine equipment. The steam control valve 16 and the steam stop valve 15 are provided in the steam pipe 31 </ b> A, and the steam control valve 16 is disposed on the downstream side of the steam stop valve 15. The steam supplied to the steam turbine equipment via the steam pipe 31A is supplied to the steam turbine and rotationally drives the steam turbine.

  In the present embodiment configured as described above, the steam control valve 16 is used as means for increasing the pressure in the drum 13. If the steam control valve 16 is throttled based on the temperature of the exhaust gas 14, the temperature of the exhaust gas 14 can be increased as in the first embodiment. Therefore, also in the present embodiment, the draft force of the exhaust gas 14 can be ensured without reducing the thermal efficiency as much as possible. Further, as in the first embodiment, the present invention can be widely applied when it is necessary to avoid a decrease in exhaust gas temperature during normal operation (increase the exhaust gas temperature), in addition to ensuring draft power.

  Also, from the viewpoint of the operation method of this combined power plant, when it is necessary to increase the exhaust gas temperature at the outlet of the exhaust heat recovery boiler, as an operation method to increase the exhaust gas temperature, the opening of the steam control valve is reduced, It can be said that this is an operation method in which the pressure in the drum of the exhaust heat recovery boiler is adjusted high. Here, the operation of reducing the opening of the steam control valve is performed when the outlet temperature of the exhaust heat recovery boiler becomes lower than the set temperature, so that it is not necessary to operate the steam control valve in a complicated manner. Since the steam control valve is not throttled unnecessarily, a decrease in efficiency is also suppressed.

  FIG. 3 is a schematic view of the vicinity of the HRSG in the combined power plant according to the third embodiment of the present invention.

  The combined power plant shown in this figure includes a control device 17A that outputs an operation signal to the steam control valve 16 and the steam stop valve 15. If the opening degree of the steam stop valve 15 is configured to be adjustable by the control device 17A as described above, not only the steam control valve 16 but also the steam stop valve 15 can be used to increase the pressure in the drum 13. When the pressure in the drum 13 is increased using the steam control valve 16 and the steam stop valve 15 in this way, the pressure increase value of the drum 13 can be increased compared to the second embodiment. It becomes possible to cope with a large increase in atmospheric temperature that could not be dealt with in the previous embodiment.

  Further, in the second embodiment and the third embodiment, the present invention is also applicable to a steam combination valve in which a steam control valve and a steam stop valve are integrated in one body.

  FIG. 4 is a schematic view of the vicinity of the HRSG in the combined power plant according to the fourth embodiment of the present invention.

  The combined power plant shown in this figure includes a reheat triple pressure HRSG 11A including three drums 20 (a low pressure drum 20a, an intermediate pressure drum 20b, and a high pressure drum 20c). The low-pressure drum 20a is provided on the most downstream side in the flow direction of the exhaust gas 30 among the three drums 20a, 20b, and 20c, and a steam pipe 31B is connected to the low-pressure drum 20a. The steam pipe 31B is connected to the steam turbine equipment 23 including a plurality of steam turbines (low pressure turbine 23a, intermediate pressure turbine 23b, high pressure turbine 23c) via the low pressure steam stop valve 21 and the low pressure steam control valve 22. Steam is supplied to the lowest pressure turbine (low pressure turbine 23a) among the plurality of steam turbines.

  If the combined power plant is configured in this way, the temperature of the exhaust gas 14 can be raised only by reducing the heat exchange amount in the low pressure drum 20a, so that the heat exchange amount in the intermediate pressure drum 20b and the high pressure drum 20c is kept constant. can do. Accordingly, it is possible to minimize a decrease in heat exchange efficiency in the HRSG 11A.

  In the present embodiment, only the case where the opening of the steam control valve 22 is reduced has been described. However, when the steam control valve 22 alone is not sufficient, the steam stop valve 21 is provided as in the third embodiment. Needless to say, you can squeeze it. Although the case where there are three drums 20 has been described here, the present invention can also be applied to the case where there are two or four or more drums.

  FIG. 5 is a schematic view of the vicinity of the HRSG in the gas turbine equipment according to the fifth embodiment of the present invention. The present embodiment is different from the first embodiment in that the set temperature T1 of the exhaust gas 14 is calculated based on the atmospheric temperature and the gas turbine load.

  The gas turbine equipment shown in this figure includes a control device 17B. An air temperature detection signal 18 and an air turbine load signal 19 from an air temperature detector (atmosphere temperature detecting means) (not shown) for detecting the air temperature are input to the control device 17B. The control device 17B acquires the set temperature T1 of the exhaust gas 14 based on the temperature detection signal 18 and the gas turbine load signal 19 input in this way. Specifically, the control device 17B in the present embodiment stores a plurality of set temperature tables in which a set temperature T1 is determined for an arbitrary gas turbine load in a storage unit (ROM or the like). The set temperature T1 is obtained using a table. Here, a case where the gas turbine facility is operated at a rated load will be described as an example.

FIG. 6 shows an example of a set temperature table in which the set temperature T1 during rated load operation is defined.
In this figure, the horizontal axis indicates the atmospheric temperature (x), and the vertical axis indicates the HRSG outlet exhaust gas temperature (T (x)). The temperature (T (x)) of the exhaust gas 14 decreases as the atmospheric temperature (x) increases as shown in the figure. Further, in FIG. 6, a set temperature T <b> 1 at the rated load operation for ensuring the draft force of the exhaust gas is set. In the present embodiment, T1 is, for example, 95 ° C. when the atmospheric temperature (x) is, for example, 25 ° C. or higher.

  In the present embodiment, the control device 17B determines the operating status of the gas turbine equipment based on the gas turbine load signal 19, and selects a set temperature table corresponding to the operating status. Here, since the gas turbine equipment is operated at the rated load, the table of FIG. 6 corresponding to the rated load operation is selected from a plurality of set temperature tables. Since the selected table has a set temperature T1 of the exhaust gas 14 as shown in FIG. 6, the control device 17B adjusts the throttle amount of the steam control valve 24 based on this set temperature T1. .

  Next, the control device 17B acquires the current atmospheric temperature (x1) based on the temperature detection signal 18, and determines whether the atmospheric temperature (x1) is a temperature at which the set temperature T1 is determined. judge. Here, for example, since the set temperature T1 is determined when the temperature is 25 ° C. or higher, it is determined whether or not x1 is 25 ° C. or higher. If x1 is 25 ° C. or higher, the control device 17B adjusts the throttle amount of the steam control valve 24 so that the temperature of the exhaust gas 14 is maintained at, for example, 95 ° C. or higher as in the first embodiment. To do. Thereby, also in this Embodiment, even if atmospheric temperature rises, the draft force of the waste gas 14 is securable.

  According to the present embodiment configured as described above, the temperature of the exhaust gas 14 can be adjusted based on the set temperature T1 according to the gas turbine load, so that it is compared with the case of the first embodiment. Efficiency can be improved. In addition, since it is possible to determine whether to perform exhaust gas temperature control based on the atmospheric temperature, it is possible to clarify the range in which temperature control is performed.

  In the above description, the case where the temperature of the exhaust gas 14 is controlled to be, for example, uniformly 95 ° C. or more when the atmospheric temperature is 25 ° C. or more, for example, but the set temperature T1 corresponding to the atmospheric temperature is set individually. The temperature may be controlled using a setting table. When the set temperature is set in accordance with the atmospheric temperature in this way, the temperature control can be performed based on the optimum exhaust gas temperature for the atmospheric temperature at the time of control, so that the heat exchange efficiency in the HRSG 11 can be further improved.

  FIG. 7 is a schematic view of the vicinity of the HRSG in the combined power plant according to the sixth embodiment of the present invention. The combined power plant shown in this figure has the same control device 17B as that of the fifth embodiment, and corresponds to the control device 17B applied to the second embodiment. That is, the control device 17B acquires the set temperature of the exhaust gas 14 based on the gas turbine load signal 19 and adjusts the steam control valve 16 based on the temperature detection signal 18 to adjust the temperature of the exhaust gas 14. By using the control device 17B in this way, temperature control according to the gas turbine load becomes possible, so that the efficiency can be improved compared to the case of the second embodiment.

  FIG. 8 is a schematic view of the vicinity of the HRSG in the combined power plant according to the seventh embodiment of the present invention. The combined power plant shown in this figure corresponds to a control device 17B applied to the fourth embodiment. In this embodiment having the reheat triple pressure type HRSG 11A as described above, if the control device 17B is applied, the temperature control corresponding to the gas turbine load is performed as in the fifth and sixth embodiments. Can do.

  Here, the case where the control device 17B is applied to the third embodiment has not been described. However, if the control device 17B is applied, the temperature according to the gas turbine load is similar to the above-described embodiment. Needless to say, control becomes possible.

  By the way, in each of the above-described embodiments, the control for improving the temperature of the exhaust gas 14 when the atmospheric temperature rises has been described. However, the present invention is also applied when the temperature of the exhaust gas 14 is limited when the atmospheric temperature is low. It may be applied. As a specific example in this case, for example, there is a case where the temperature of the exhaust gas 14 is controlled to 98 ° C. or more at an atmospheric temperature of 0 ° C.

  In each of the above embodiments, the control for improving the temperature of the exhaust gas 14 when the predetermined atmospheric temperature is reached has been described. However, when the amount of exhaust gas discharged to the atmosphere is large and the environmental load exceeds a certain value. That is, when the gas turbine load exceeds a certain value, the temperature control of the exhaust gas 14 may be performed to improve the diffusing power of air pollutants.

  Further, the temperature control of the exhaust gas 14 may be performed only when the temperature difference (ΔT) between the HRSG outlet exhaust gas temperature and the atmospheric temperature falls below a certain value, and the draft force of the exhaust gas 14 may be improved.

  In the above description, the case where the heat medium heated by HRSG is water has been described. However, other heat medium may be used.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic of the waste heat recovery boiler equipment which is the 1st Embodiment of this invention. Schematic of HRSG vicinity in the combined power plant which is the 2nd Embodiment of this invention. Schematic of HRSG vicinity in the combined power plant which is the 3rd Embodiment of this invention. Schematic of HRSG vicinity in the combined power plant which is the 4th Embodiment of this invention. Schematic of HRSG vicinity in the gas turbine equipment which is the 5th Embodiment of this invention. The figure which shows the preset temperature table in which preset temperature T1 at the time of rated load driving | operation is defined in the 5th Embodiment of this invention. Schematic of HRSG vicinity in the combined power plant which is the 6th Embodiment of this invention. Schematic of HRSG vicinity in the combined power plant which is the 7th Embodiment of this invention.

Explanation of symbols

11 Waste heat recovery boiler (HRSG)
12 exhaust gas temperature detector 13 drum 14 HRSG outlet exhaust gas 15 steam stop valve 16 steam control valve 17 controller 18 atmospheric temperature detection signal 19 gas turbine load signal 20 drum 20a low pressure drum 20b medium pressure drum 20c high pressure drum 22 low pressure steam control valve 21 Low pressure steam stop valve 23 Steam turbine 23a Low pressure turbine 23b Medium pressure turbine 23c High pressure turbine 24 Steam control valve 30 Gas turbine exhaust gas 31 Steam pipe T1 Set temperature

Claims (9)

A combined power plant comprising a gas turbine facility, an exhaust heat recovery boiler, and a steam turbine facility,
Exhaust gas temperature detection means for detecting the exhaust gas temperature at the outlet of the exhaust heat recovery boiler;
When the temperature detected by the exhaust gas temperature detection means is lower than the set temperature, the steam control valve or steam stop valve provided in the steam pipe for supplying steam from the exhaust heat recovery boiler to the steam turbine of the steam turbine equipment is opened. And a control device that outputs an operation signal so as to reduce the degree. The combined power plant according to claim 1,
The combined power plant, wherein the set temperature is set to ensure a draft force in a chimney of exhaust gas discharged from the exhaust heat recovery boiler. The combined power plant according to claim 2,
The combined power plant, wherein the set temperature is set according to a gas turbine load. The combined power plant according to claim 1,
The exhaust heat recovery boiler has a plurality of drums having different steam pressures,
The control device sends an operation signal to restrict the opening degree of the steam control valve or the steam stop valve provided in the steam pipe connected to the drum having the lowest steam pressure among the plurality of drums. A combined power plant characterized by output. A method for operating a combined power plant comprising a gas turbine facility, an exhaust heat recovery boiler, and a steam turbine facility,
As an operation method for increasing the exhaust gas temperature at the outlet of the exhaust heat recovery boiler,
The opening of the steam control valve or steam stop valve provided in the steam pipe for supplying steam from the exhaust heat recovery boiler to the steam turbine of the steam turbine equipment is throttled, and the pressure in the drum of the exhaust heat recovery boiler is adjusted high. A method for operating a combined power plant. An exhaust heat recovery boiler that evaporates a heat medium with exhaust gas from an exhaust heat source, collects the evaporated heat medium in a drum, and supplies the heat medium from the drum to a heat medium utilization facility,
A heat medium supply system for supplying the heat medium from the drum to the heat medium utilization facility;
A steam amount adjusting means provided in the heat medium supply system for adjusting the amount of the heat medium supplied to the heat medium utilization facility;
Exhaust gas temperature detection means for detecting the exhaust gas temperature at the outlet of the exhaust heat recovery boiler;
An exhaust heat recovery boiler, comprising: a control device that adjusts the pressure in the drum by the steam amount adjusting means so that the detected temperature of the exhaust gas temperature detecting means is maintained at a set temperature or higher. In the exhaust heat recovery boiler according to claim 6,
The said control apparatus adjusts the pressure in the said drum by the said steam | vapor amount adjustment means so that the detection temperature of the said waste gas temperature detection means approaches the said preset temperature, The exhaust heat recovery boiler characterized by the above-mentioned. In the exhaust heat recovery boiler according to claim 6,
The heat medium utilization facility is a steam turbine of a steam turbine facility,
The steam quantity adjusting means is a steam control valve or a steam stop valve. In the exhaust heat recovery boiler according to claim 8,
The drum is composed of a plurality of drums having different vapor pressures,
The control device is provided in the heat medium supply system connected to a drum having the lowest steam pressure among the plurality of drums so that the detected temperature of the exhaust gas temperature detecting means is maintained at the set temperature or higher. Further, the exhaust heat recovery boiler is characterized by adjusting the steam amount adjusting means.

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