JP6548989B2 - Combined cycle power plant thermal energy storage - Google Patents

Description

  The present invention relates generally to combined cycle power plants. More particularly, the present invention relates to a system and method for storing thermal energy in a heat recovery steam generator section of a combined cycle power plant during operation of rotating and / or non-combustible gears of a gas turbine.

  One type of combined cycle gas turbine power plant combines at least one gas turbine and at least one steam turbine to generate electrical power. The power plant is configured such that the gas turbine is thermally connected to the steam turbine through a heat recovery system, such as a Heat Recovery Steam Generator (HRSG). Gas turbines generally include a compressor section, a combustion section disposed downstream from the compressor section, and a turbine section downstream from the combustion section. A rotor shaft of the gas turbine is coupled to the generator. The rotor shafts of the steam turbine may be connected to the same generator or to another generator.

  In general, the HRSG includes one or more heat exchangers located downstream from the turbine exhaust duct of the gas turbine. During the combustion operation of the gas turbine, hot combustion exhaust gases exit the exhaust stack from the exhaust duct through the HRSG. Thermal energy from the hot combustion exhaust gases is converted to a working fluid, such as water, via a heat exchanger, and a stream of pressurized steam is supplied to the steam turbine.

  In some instances, the gas turbine may operate primarily during peak or high power demand periods and shut down during non-peak or low demand periods. However, during shutdown or non-combustion operation, the rotor shaft of the gas turbine is kept rotating at any desired minimum rotational speed via the rotating gear connected to the electric motor to protect the gas turbine rotor from bending. Is generally desirable.

  As the rotor rotates through the rotating gear, ambient air is drawn through the compressor section, led into the compressor discharge case of the combustion section, led through the turbine section out of the exhaust duct, and then passed to the HRSG Be done. The air flowing from the compressor during rotary gear operation may slightly increase the thermal energy, but the temperature of the air passing from the compressor into the HRSG may be particularly short after combustion operation of the gas turbine has ceased , May be lower than the temperature of the working fluid staying in the heat exchanger of the HRSG. As a result, thermal energy from the working fluid in the heat exchanger is lost to the lower temperature exhaust air.

  The loss of thermal energy from the working fluid at the HRSG during rotary gear operation can adversely affect overall plant performance. For example, time may be required to bring the working fluid within the HRSG back to the required operating temperature before maximum operation of both gas and steam turbines can be realized. In addition, the large temperature difference between the working fluid within the HRSG and the hot turbine exhaust gases results in the thermal stress on the various parts of the HRSG, especially during the first start-up period, which contributes to the overall HRSG performance. It may affect. Accordingly, systems and methods for preserving heat loss from HRSG working fluid during rotary gear operation of a gas turbine would be beneficial.

  Aspects and advantages of the present invention are detailed in the description that follows, or may become apparent from the description, or may be understood through practice of the present invention.

  One embodiment of the present invention is a combined cycle power plant. The combined cycle power plant includes a main flow path, a heat recovery steam generator having a heat exchanger disposed downstream of the main flow path, and an exhaust flow downstream of the heat recovery steam generator in fluid communication with the main flow path. A gas turbine including a cylinder and a reversible rotating gear coupled to a rotor shaft of the gas turbine. The reversible rotation gear reversely rotates the rotor shaft during the rotary gear reverse rotation operation of the gas turbine to reverse the flow of the combustion exhaust gas and return it from the exhaust stack into the main flow path of the gas turbine through the heat exchanger. Store the thermal energy stored in the heat recovery steam generator.

  Another embodiment of the present disclosure is a method for storing thermal energy of a combined cycle power plant during rotary gear operation. The combined cycle power plant includes a gas turbine having a rotor shaft, a heat recovery steam generator downstream from an exhaust outlet of the gas turbine, and an exhaust stack downstream from the heat recovery steam generator. The method directs the combustion exhaust gases from the gas turbine through the heat recovery steam generator into the exhaust stack during the combustion operation of the gas turbine, in which case the rotor shaft rotates in the normal direction of rotation and stops the combustion section of the gas turbine The step of decelerating and finally stopping the rotor shaft is thereby included. The method further includes the step of reversing the rotor shaft of the gas turbine via the reversible rotating gear, wherein the rotor shaft reversely rotates so that the combustion exhaust gas is recovered from the exhaust stack in the reverse flow direction. And through the main flow path of the gas turbine.

  The invention also includes a method for storing thermal energy of a combined cycle power plant. The combined cycle power plant includes a gas turbine having a rotor shaft, a heat recovery steam generator downstream from an exhaust outlet of the gas turbine, and an exhaust stack downstream from the heat recovery steam generator. The method includes the step of directing the combustion exhaust gases from the gas turbine through the heat recovery steam generator into the stack during the combustion operation of the gas turbine, in which case the rotor shaft rotates in the normal direction of rotation. In addition, the method includes the step of stopping the combustion section of the gas turbine, thus making it possible to decelerate the rotor shaft to a speed sufficient to engage a reversible rotating gear for rotating the rotor shaft. The method also includes the step of reversing the rotor shaft through the reversible rotating gear, wherein the rotor shaft reversely rotates to pass the combustion exhaust gas from the stack in the reverse flow direction through the heat recovery steam generator and It pulls back through the main flow path of the gas turbine. The method further comprises the steps of measuring the temperature of the combustion exhaust gas as it exits the inlet section of the gas turbine, and comparing the measured combustion exhaust gas temperature to a predetermined maximum compressor inlet temperature, wherein the measured temperature is The rotary gear continues reverse rotation of the rotor shaft below the predetermined maximum compressor inlet temperature, and the rotation gear stops reverse rotation of the rotor shaft when the temperature exceeds the predetermined maximum compressor inlet temperature, and normal rotation of the rotor shaft Including resuming steps.

  Those skilled in the art will better understand the features and aspects of such embodiments, and others, upon review of the specification.

  The complete and effective disclosure of the present invention, including the best mode for those skilled in the art, is more specifically described in the remaining part of the specification, including the reference to the attached drawings.

FIG. 1 is a functional block diagram of an exemplary gas turbine that may incorporate various embodiments of the present invention. FIG. 2 is a functional block diagram of an exemplary gas turbine as shown in FIG. 1 according to various embodiments of the present invention. FIG. 3 is a block diagram representing a method for storing thermal energy of a combined cycle power plant as shown in FIG. 2 according to one embodiment of the present invention. FIG. 3 is a block diagram representing a method for storing thermal energy of a combined cycle power plant as shown in FIG. 2 according to one embodiment of the present invention.

  Reference will now be made in detail to the present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description refers to features in the drawings using number and letter designations. Similar or similar designations in the drawings and specification are used to refer to like or similar parts of the invention. As used herein, the terms "first", "second" and "third" are used interchangeably to distinguish one part from another Also, these terms are not intended to indicate the location or importance of the individual components. The terms "upstream" and "downstream" refer to the relative direction to fluid flow in the flow path. For example, "upstream" refers to the direction from which fluid flows, and "downstream" refers to the direction into which fluid flows.

  Each example is provided by way of explanation of the invention, but not as a limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For example, features illustrated and described as part of one embodiment may be used on another embodiment to yield yet another embodiment. Thus, the present invention is intended to cover such modifications and variations as fall within the scope of the appended claims and their equivalents. An exemplary embodiment of the present invention is, by way of example, a combined cycle power generation with a single gas turbine, a single steam turbine, and a single heat recovery steam generator, in particular a single heat exchanger. Although generally described in the context of the present invention, as one of ordinary skill in the art will readily appreciate, embodiments of the present invention include any combination cycle having multiple gas turbines, steam turbines, and / or multiple HRSG units. It may be applied to a power plant.

  Referring now to the drawings, like numerals indicate like elements throughout the figures and FIG. 1 provides a functional block diagram of a typical combined cycle power plant 10 that may incorporate various embodiments of the present invention. As shown in FIG. 1, power plant 10 generally includes a gas turbine 12. Gas turbine 12 generally includes an inlet section 14 which may include a series of filters, cooling coils, moisture separators, and / or devices (not shown) for purifying and conditioning air 16 entering gas turbine 12. Including. A compressor section 18 including a compressor 20 is disposed downstream from the inlet section 14. Disposed downstream from the compressor 20 is a combustion section 22 including a plurality of combustors 24 disposed annularly around an outer case 26 such as a compressor discharge case. In particular embodiments, the outer case 26 defines a high pressure plenum 28 therein.

  A turbine section 30 including high and / or low pressure turbines 32 is disposed downstream from the combustion section 22. In one embodiment, gas turbine 32 includes an exhaust section 34 including an exhaust duct or diffuser 36 disposed downstream from the outlet of turbine 32. In particular embodiments, the inlet section 14, the compressor 20, the outer case 26 of the combustion section 22, the turbine 32, and the exhaust duct 36 define a main flow path 38 through the gas turbine 12.

  A rotor shaft 40 extends along an axial center line of the gas turbine 12. The rotor shaft 40 may be a single shaft or may include multiple shafts coupled together to form a single shaft through the gas turbine 12. The compressor 20 generally comprises a plurality of rows or stages of compressor blades 42, where each row of compressor blades 42 is connected to the rotor shaft 40 via a compressor rotor disk 44. Further, the turbine 32 generally includes a plurality of rows or stages of turbine blades 46, where each row of turbine blades is coupled to the rotor shaft 40 via a turbine rotor disk 48. The compressor blades 42 and the turbine blades 46 are generally mounted and angled such that the normal rotation of the rotor shaft 40 in the normal direction of rotation 50 causes the air 16 to be drawn into the compressor 20 through the inlet section 14 And / or formed. Although illustrated counterclockwise, the normal direction of rotation 50 may be either clockwise or counterclockwise depending on the configuration of the compressor blade 42 and the turbine blade 46.

  The combined cycle power plant 10 also includes a heat recovery steam generator 52 disposed downstream from at least one of the turbine 32 and the exhaust duct 36. The heat recovery steam generator 52 generally includes at least one heat exchanger 54 in fluid communication with the main flow path 38 of the gas turbine 12. The heat exchanger 52 is fluidly coupled to one or more steam turbines 56 that may be connected to a generator 58 for generating electrical power.

  During the combustion operation of the gas turbine 12 in which the rotor shaft 40 rotates in the normal direction of rotation 50, the rotating compressor blades 42 cause the air 16 to pass through the inlet section 14 into the compressor 20 where it enters the main flow path 38 As it travels along, it is gradually compressed, whereby compressed air 60 is supplied to the combustion zone 22. At least a portion of the compressed air 60 is directed into various combustors 24 where it is mixed with fuel to provide a combustible fuel-air mixture. The fuel-air mixture in each combustor 24 burns to provide high temperature, high pressure, high velocity combustion gases 62. The combustion gases 62 are then directed into the turbine 32 where kinetic energy is transferred from the combustion gases 62 through the turbine rotor blades 48, which causes the rotor shaft 40 to rotate.

  Combustion gases 64 exit turbine 32 and pass through exhaust duct 36 as combustion exhaust gases 64. The combustion exhaust gas 64 flows through and / or across the heat exchanger 54 of the heat recovery steam generator 52, where a portion of the remaining thermal energy from the combustion exhaust gas 64 is through the heat exchanger 54. It is converted to a working fluid 66 such as water. In general, the transferred thermal energy is sufficient to convert the working fluid 66 into steam 68. The steam 68 is then directed to the steam turbine 56. The combustion exhaust gas 64 is then directed through the stack or exhaust duct 70 and is generally released to the atmosphere. Even after the combustion exhaust gas 64 flows across the heat exchanger 54 of the heat recovery steam generator 52, it retains a significant amount of thermal energy. Furthermore, when the unit is at rest and in rotary gear operation, heat transfer may be from the working fluid of the heat recovery steam generator to the air flow induced by the rotary gear operation of the gas turbine compressor. .

  FIG. 2 provides a schematic side view of an exemplary combined cycle power plant 10, as shown in FIG. 1, in accordance with various embodiments of the present invention. In various embodiments, as shown in FIGS. 1 and 2, a generator / motor 72 is coupled to the rotor shaft 40 via a rotating gear 76. In a specific embodiment, the rotating gear 76 and / or the motor 72 are reversible. In other words, the rotary gear 76 and / or the motor 72 rotate the rotor shaft 40 either in the normal direction of rotation 50 (FIG. 1) or in the reverse direction of rotation 76 (FIG. 2) opposite or opposite to the normal direction of rotation 50 Configured to

  In one embodiment, as shown in FIG. 2, the gas turbine 12 includes one or more bleed ports 78 in fluid communication with the blower or air pump 80 and the main flow passage 38. The bleed ports 78 may be disposed at various points along the gas turbine 12. For example, in one embodiment, a bleed port 82 is disposed along the inlet section 14 and is in fluid communication with a portion of the main flow path 38 defined in the inlet section 14. In one embodiment, a bleed port 84 is disposed along the compressor 20 of the compressor section 18 and is in fluid communication with a portion of the main flow path 38 defined within the compressor 20. In one embodiment, a bleed port 86 is disposed along the outer case 26 of the combustion section 22 and is in fluid communication with a portion of the main flow passage 38 defined in the outer case 26 and / or the high pressure plenum 28. . In one embodiment, a bleed port 88 is disposed along the turbine 32 of the turbine section 30 and is in fluid communication with a portion of the main flow path 38 defined within the turbine 32. In one embodiment, a bleed port 90 is disposed along the exhaust duct 36 of the exhaust section 34 and is in fluid communication with a portion of the main flow path 38 defined within the exhaust duct 36.

  The combined cycle power plant 10 includes any or all of the bleed ports 78 as shown in FIG. The bleed vent 78 is not limited to any particular arrangement along a particular section or part of the gas turbine 12 unless specifically stated in the claims.

  The blower 80 is any blower motor suitable for drawing air 16 and / or combustion exhaust gas 64 back from the main flow path 38 in the corresponding section or part of the gas turbine 12 during rotary gear reverse rotation operation of the gas turbine 12 It may include a pump or device. In certain embodiments, the blower 80 is in fluid communication with the exhaust stack 70, thus providing a flow path between the main flow passage 38 and the exhaust stack 70.

  In a particular embodiment, the stack 70 includes at least one moveable hatch 92. In the closed or at least partially closed position, the hatch 92 seals or at least partially seals the stack 70 from the atmosphere. In the open state, as seen in dashed line, the hatch 92 vents the combustion exhaust gas 64 to the atmosphere. In one embodiment, the hatch 92 is at least partially closed to retain at least a portion of the combustion exhaust gas 64 within the exhaust stack 70.

  Conventionally, when the gas turbine 12 is stopped or operating in a non-combustible state, the rotary gear 76 is engaged to keep the rotor shaft 40 rotating, thereby allowing the rotor shaft 40 to bend. And / or improve the rise time required to bring the combined cycle power plant 10 back into operation. However, as the rotating gear 76 turns the rotor shaft 40 in the normal rotational direction 50, ambient air 16 is drawn into the compressor 20 through the inlet 14 where it is along the main flow path 38 and the outer case 26 of the combustion zone 22. , Through the turbine 32, through the exhaust duct 36, and over the heat exchanger 54 of the heat recovery steam generator 52. The air 16 flowing across the heat exchanger 54 is at a relatively lower temperature than the working fluid 66 stored in the heat exchanger 54. As a result, thermal energy is lost to the lower temperature air 16, thus potentially reducing the overall efficiency of the heat recovery steam generator 52 and / or the combined cycle power plant 10.

  As described herein and illustrated in FIGS. 1 and 2, various embodiments of the combined cycle power plant may be integrated into the heat recovery steam generator 52, particularly during rotary gear operation of the gas turbine 12. A method 100 is provided for storing the thermal energy stored in the working fluid 64 stored in the heat exchanger 54 or in the heat exchanger of the heat recovery steam generator 52. For example, in step 102, as shown in FIG. 3 and as illustrated in FIG. 1, the method 100 generates heat recovery steam from the combustion exhaust gas 64 from the gas turbine 12 during the combustion operation of the gas turbine 12. Leading through the vessel 52 into the exhaust stack 70, in which case the rotor shaft 40 rotates in the normal direction of rotation 50 (FIG. 1). As shown in FIG. 3, at step 104, the method 100 includes shutting off the combustion zone 22 of the gas turbine 12. Stopping the combustion zone 22 may include reducing or stopping the fuel supply to the combustor 24. Method 100 further slows down and / or temporarily stops rotor shaft 40 so that rotating gear 76 and / or motor 72 may be engaged after stopping combustion section 22 of gas turbine 12. May be included.

  As shown in FIG. 3 and illustrated in FIG. 2, in step 106, the method reversely rotates the rotor shaft 40 (in reverse rotation direction 76) via the rotating gear 74 and / or the motor 72, in this case When the rotor shaft 40 reversely rotates, the combustion exhaust gas 64 is pulled back through the heat recovery steam generator 52 and at least partially through the main flow passage 38 in the reverse flow direction from the exhaust stack. For example, combustion exhaust gas 64 may enter exhaust duct 36, flow through turbine 32, combustion section 22, and compressor 20, then flow toward and / or out of inlet section 14. Because the combustion exhaust gas 64 is hotter than the air 16 from the atmosphere, the heat transfer coefficient between the combustion exhaust gas 64 and the working fluid 64 stored in the heat exchanger 54 is reduced, thus the system generates heat recovery steam The thermal energy stored in the vessel 52 can be stored, and the overall efficiency of the combined cycle power plant 10 can be improved.

  In certain embodiments, the method 100 may further include measuring the temperature of the combustion exhaust gas 64 in the section of the gas turbine 12. The temperature may be measured by one or more thermocouples or any other suitable sensor or sensors (not shown). The temperature may be taken at any one or more locations. For example, the temperature may be measured at one or more of an exhaust stack 70, a heat recovery steam generator 52, an exhaust duct 36, a turbine 32, a combustion section 22, a compressor 18, and / or an inlet section 14. .

  In one embodiment, the method 100 also causes the rotor shaft to measure when the measured temperature within the section of the gas turbine 12 including but not limited to the heat recovery steam generator 52 and / or the exhaust stack 70 exceeds a predetermined limit. It may include stopping the reverse rotation of 40 and resuming the normal rotation of the rotor shaft 40. For example, various components found in the inlet section 14, such as an air filter, may have a maximum temperature limit, for example, in the range of 150 to 250 degrees Fahrenheit which may be well below the temperature of the combustion exhaust gas 64.

  In certain embodiments, the method 100 directs at least a portion of the combustion exhaust gas 64 back from the main flow path 38 via various fluid conduits into the exhaust stack 70 during rotary gear reverse rotation operation of the gas turbine 12. Including. As a result, the latent heat energy remaining in the recirculated combustion exhaust gas 64 can be used to reduce the heat transfer coefficient between the combustion exhaust gas 64 and the working fluid 66 in the heat exchanger 54, and thus The system can store the thermal energy stored in the heat recovery steam generator 52 to improve the overall efficiency of the combined cycle power plant 10.

  In certain embodiments, the method 100 may also include activating the blower 80 during rotary gear reverse rotation operation, where the blower 80 is fluidly coupled to one or more of the bleed ports 78. (FIG. 2), and in this case, one or more bleed ports 78 are in fluid communication with the main flow path 38. This can reduce the volume of the combustion exhaust gas 64 being directed towards the inlet section 14 so that the system can maintain an acceptable temperature at the inlet section 14 while recirculating combustion. The latent heat energy remaining in the exhaust gas 64 can be used to further preserve the thermal energy stored in the heat recovery steam generator 52 to improve the overall efficiency of the combined cycle power plant 10.

  In one embodiment, the method 100 may further include at least partially sealing the stack 70 from the atmosphere via the hatch 92 during the rotary gear reverse rotation operation of the gas turbine (FIG. 2), The system can store the thermal energy stored in the heat recovery steam generator 52 and improve the overall efficiency of the combined cycle power plant 10.

  FIG. 4 provides a flow diagram of a method 200 for storing thermal energy of combined cycle power plant 10, according to one embodiment of the present invention. The method 200 includes, at step 202, directing the combustion exhaust gas 64 from the gas turbine 12 through the heat recovery steam generator 52 and into the exhaust stack 70 during the combustion operation of the gas turbine 12. The method 200 includes stopping the combustion zone 22 of the gas turbine 12 at step 204. The method 200 includes, at step 206, reversing the rotor shaft 40 via the reversible rotation gear 74 and / or the motor 72, wherein the rotation of the rotor shaft 40 causes the combustion exhaust gas 64 to enter the exhaust stack 70. From the heat recovery steam generator 52 and back through the main flow path 38 of the gas turbine 12 in the reverse flow direction. The method 200 includes measuring the temperature of the combustion exhaust gas 64 as it exits the inlet section 14 of the gas turbine 12 at step 208. The method 200 at step 210 compares the measured temperature of the combustion exhaust gas 64 to a predetermined maximum compressor inlet temperature, and if the measured temperature is below the predetermined maximum compressor inlet temperature, the rotating gear 74 The rotor gear 40 and / or the motor 72 stops the reverse rotation of the rotor shaft 40 and resumes the normal rotation of the rotor shaft 40 when the rotor shaft 40 continues to reversely rotate and the temperature exceeds the predetermined maximum compressor inlet temperature. including.

  This written description uses examples to disclose the invention, including the best mode, and also includes making and using any apparatus or system and performing any incorporated method. Allowing those skilled in the art to practice the present invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other instances are within the scope of the claims, if they contain structural elements that do not differ from the wording of the claims, or if they contain equivalent structural elements that do not differ substantially from the wording of the claims. Do.

DESCRIPTION OF SYMBOLS 10 combined cycle power plant 12 gas turbine 14 inlet area 16 air 18 compressor area 20 compressor 22 combustion area 24 combustor 26 outer case 28 high pressure plenum 30 turbine area 32 turbine 34 exhaust area 36 exhaust duct, diffuser 38 main flow path 40 rotor Shaft 42 compressor blade 44 compressor rotor disk 46 turbine blade 48 turbine rotor disk 50 normal rotation direction 52 heat recovery steam generator 54 heat exchanger 56 steam turbine 58 generator 60 compressed air 62 combustion gas 64 combustion exhaust gas 66 working fluid 68 steam 70 exhaust cylinder, exhaust duct 72 generator / motor 74 rotating gear 76 reverse rotation direction 78, 82, 84, 86, 88, 90 extraction port 80 blower or air pump 92 movable hatch

Claims (19)

A gas turbine (12) having a main shaft (38) defined therein and having a rotor shaft (40);
A heat recovery steam generator (52) having a heat exchanger (54) disposed downstream from the main flow passage (38);
An exhaust pipe (70) disposed in fluid communication with the main flow path (38) and disposed downstream from the heat recovery steam generator (52);
And a reversible rotating gear (74) connected to the rotor shaft (40) of the gas turbine (12),
The reversible rotation gear (74) reversely rotates the rotor shaft (40) during the rotary gear reverse rotation operation of the gas turbine (12) to reverse the flow of the combustion exhaust gas (64), and the exhaust cylinder A combined cycle power plant (10), from (70) through the heat exchanger (54) back to the main flow path (38) of the gas turbine (12). The main flow passage (38) is at least partially defined by one or more of an exhaust duct (36), a turbine (32), a compressor discharge case, a compressor (20), and an inlet (14) A combined cycle power plant (10) according to claim 1. The exhaust arrangement (70) according to claim 1, wherein the exhaust arrangement (70) comprises a hatch (92), which at least partially seals the exhaust gas from the gas turbine (12) into the exhaust arrangement (70). Combined cycle power plant (10). The gas turbine (12) includes a bleed port (78, 82, 84, 86, 88, 90) in fluid communication with the main flow path (38), and the bleed port (78, 82, 84, 86, A combined cycle power plant (10) according to any of the preceding claims, wherein 88, 90) are fluidly connected to said stack (70). A combined cycle power plant (10) according to claim 4, wherein the bleed port (82) is located along the inlet section (14) of the gas turbine (12). A combined cycle power plant (10) according to claim 4, wherein the bleed port (84) is located along a compressor (20) of the gas turbine (12). A combined cycle power plant (10) according to claim 4, wherein the bleed port (86) is located along the outer case (26) of the combustion section (22) of the gas turbine (12). A combined cycle power plant (10) according to claim 4, wherein the bleed port (88) is located along a turbine (32) of the gas turbine (12). A combined cycle power plant (10) according to claim 4, wherein the bleed port (90) is located along an exhaust duct (36) of the gas turbine (12). The fuel cell system further comprises a blower (80) fluidly connected to the bleed port (78, 82, 84, 86, 88, 90) and the exhaust pipe (70), the blower (80) comprising the main flow passage (38). A combined cycle power plant (10) according to claim 4, providing fluid communication between the) and the stack (70). A method of storing thermal energy of a combined cycle power plant (10) during operation of a rotating gear (74), said combined cycle power plant (10) comprising a rotor shaft (40), a gas turbine (12), A heat recovery steam generator (52) downstream from an exhaust outlet (36) of the gas turbine (12), and an exhaust stack (70) downstream from the heat recovery steam generator (52);
Directing combustion exhaust gas (64) from the gas turbine (12) through the heat recovery steam generator (52) into the exhaust stack (70) during the combustion operation of the gas turbine (12); Guiding the rotor shaft (40) to rotate normally.
Stopping the combustion section (22) of the gas turbine (12);
Reverse rotating the rotor shaft (40) of the gas turbine (12) through the rotating gear (74), and rotating the rotor shaft (40) in reverse, the combustion exhaust gas (64) And reverse rotation) from the exhaust stack (70) of the gas turbine (12) in the reverse flow direction, pulling it back through the heat recovery steam generator (52) and through the main flow passage (38). . The method of claim 11, further comprising: measuring a temperature of the combustion exhaust gas (64) within the section of the gas turbine (12). And stopping the reverse rotation of the rotor shaft (40) and resuming normal rotation of the rotor shaft (40) when the measured temperature in the section of the gas turbine (12) is higher than a predetermined limit. The method of claim 12 comprising. The method of claim 13, wherein the predetermined temperature limit is within the range of 125 to 250 degrees Fahrenheit at the compressor (20) inlet. The method further includes activating a blower (80) during the rotating gear reverse rotation operation, the blower (80) being fluidly connected to the bleed port (78, 82, 84, 86, 88, 90), A method according to claim 11, wherein a bleed port (78, 82, 84, 86, 88, 90) is in fluid communication with the main flow passage (38). At least a portion of the combustion exhaust gas (64) from the main flow passage (38) through the blower (80) and the bleed port (78, 82, 84, 86, 88, 90) through the exhaust pipe (70) 16. The method of claim 15, further comprising: guiding into. The method according to claim 11, further comprising: at least partially sealing the exhaust stack (70) from the atmosphere during rotary gear reverse rotation operation of the gas turbine (12). During the rotary gear reverse rotation operation of the gas turbine (12), at least a portion of the combustion exhaust gas (64) from the main flow path (38) of the gas turbine (12) into the exhaust stack (70) The method of claim 11, further comprising: directing back. A gas turbine (12) having a rotor shaft (40), a heat recovery steam generator (52) downstream from an exhaust outlet (36) of the gas turbine (12), and a downstream from the heat recovery steam generator (52) A method of storing thermal energy of a combined cycle power plant (10) comprising a stack (70), comprising:
Directing combustion exhaust gas (64) from the gas turbine (12) through the heat recovery steam generator (52) into the exhaust stack (70) during the combustion operation of the gas turbine (12);
Stopping the combustion section (22) of the gas turbine (12);
Reverse rotating the rotor shaft (40) of the gas turbine (12) through the reversible rotation gear (74), the reverse rotation of the rotor shaft (40), the combustion exhaust gas (64) Reverse rotation from the exhaust stack (70) through the heat recovery steam generator (52) and the main flow path (38) of the gas turbine (12) in the reverse flow direction;
Measuring the temperature of the combustion exhaust gas (64) as it exits the inlet section (14) of the gas turbine (12);
Comparing the measured temperature of the combustion exhaust gas (64) with a predetermined maximum compressor inlet temperature, the reverse rotation of the rotor shaft (40) if the measured temperature is below the predetermined maximum compressor inlet temperature And comparing, stopping reverse rotation of said rotor shaft (40) if said temperature exceeds said predetermined maximum compressor inlet temperature.