System and method for supplying steam to a gas capture system during shutdowns

Abstract

A system can include a gas capture system (20) including a separation material, wherein the gas capture system is configured to operate a regeneration process to desorb undesired gases from the separation material to regenerate the separation material for an absorption process during a partial load operation and / or a shutdown operation; a heat recovery steam generator (16) configured to receive exhaust gases and generate steam; and a backup line (160) fluidly coupling the gas capture system to the HRSG, wherein the backup line is configured to provide steam from the HRSG (16) to the gas capture system (20) for the regeneration process during the partial load operation and / or the shutdown operation.

Description

Background Technology

[0001] This application relates generally to a system and method for supplying steam to a gas trapping system during controlled shutdown operations of a combustion system, such as a combustion-driven power plant. The invention claimed herein relates to the subject matter set forth in the appended claims.

[0002] Industrial power plants (such as combustion-driven power plants) may produce a variety of gases, including exhaust gases from combustion systems. Combustion systems may include gas turbine engines, reciprocating piston-cylinder engines, furnaces, boilers (e.g., heat recovery steam generators (HRSG)), steam turbines, or other industrial equipment. These exhaust gases may include one or more undesirable gases, such as acid gases and / or greenhouse gases. For example, undesirable gases may include carbon oxides (CO). X Such as carbon dioxide (CO2) and carbon monoxide (CO), nitrogen oxides (NO) X Such as nitrogen dioxide (NO2) and / or sulfur oxides (SO4) X Such as sulfur dioxide (SO2). In some cases, combustion-driven power plants may include a gas capture system that enables the capture of unwanted gases during operation of the combustion-driven power plant. The gas capture system may perform regeneration operations to remove unwanted gases from the separation material (e.g., stripping, desorption) by applying heat to the separation material (e.g., the adsorbent material of the adsorber and / or the solvent of the stripper). Unfortunately, during shutdown operations of a combustion-driven power plant, the regeneration of the separation material is often incomplete due to a lack of heat. Consequently, during subsequent start-up operations of the combustion-driven power plant, the previously incomplete regeneration of the separation material results in a reduced gas capture rate in the gas capture system. Therefore, there is a need to improve regeneration during shutdown operations, such as by providing additional heat to complete the regeneration. Summary of the Invention

[0003] The invention claimed herein is set forth in the appended claims. Certain embodiments corresponding to the scope of the originally claimed subject matter are outlined below. These embodiments are not intended to limit the scope of the claimed subject matter, but are merely intended to provide a brief overview of the possible forms of this subject matter. In practice, this subject matter can encompass a variety of forms that may be similar to or different from the embodiments set forth below.

[0004] In one embodiment, the system may include: a gas capture system comprising a separation material, wherein the gas capture device is configured to operate a regeneration process during partial load operation and / or shutdown operation to desorb unwanted gases from the separation material to regenerate the separation material for use in the absorption process; a heat recovery steam generator (HSRG) configured to receive exhaust gas and generate steam; and a backup line fluidly connected to the gas capture system to the HRSG, wherein the backup line is configured to supply steam from the HRSG to the gas capture system for the regeneration process during partial load operation and / or shutdown operation. More specifically, the system may include a main extraction line fluidly connected to or branching from the heat recovery steam generator and configured to supply steam from the heat recovery steam generator to the gas capture system. The backup line is also fluidly connected at least at a steam extraction location to or branching from a heat recovery steam generator, thereby providing a higher steam pressure than at the steam extraction locations where the main extraction line is connected to or branching from the heat recovery steam generator. For example, the main extraction line may branch from a line configured to supply steam to a low-pressure steam turbine or a low-pressure steam turbine section, while the backup line may branch from a line configured to supply high-pressure steam from the heat recovery steam generator to a high-pressure steam turbine or a high-pressure steam turbine section and / or a line configured to supply steam from the high-pressure steam turbine or a high-pressure steam turbine section to the heat recovery steam generator and / or a line configured to supply steam from the heat recovery steam generator to an intermediate-pressure steam turbine or an intermediate-pressure steam turbine section, or any possible combination thereof.

[0005] In another embodiment, a system may include a power plant comprising a gas turbine configured to output exhaust gas, a heat recovery steam generator (HRSG) configured to receive the exhaust gas and output steam, and a steam turbine configured to receive steam. The system may also include a carbon capture system and a controller configured to capture unwanted gases from the exhaust gas in a separation material, the controller being configured to initiate partial load operation and / or shutdown operation of the power plant. The controller may control the gas turbine to reduce to partial load conditions and continue outputting the exhaust gas, control a first set of valves to at least partially close to reduce or disable the steam flow to the steam turbine, and control a second set of valves to enable or increase the steam flow from the HRSG to the carbon capture system via a backup line for a period of time to perform a regeneration process on the separation material. As in the embodiments outlined above, the system may more specifically include a main extraction line fluidly coupled to or branching from the heat recovery steam generator and configured to supply steam from the heat recovery steam generator to the gas capture system. The backup line is also fluidly connected at least at a steam extraction location to or branching from a heat recovery steam generator, thereby providing a higher steam pressure than at the steam extraction locations where the main extraction line is connected to or branching from the heat recovery steam generator. For example, the main extraction line may branch from a line configured to supply steam to a low-pressure steam turbine or a low-pressure steam turbine section, while the backup line may branch from a line configured to supply high-pressure steam from the heat recovery steam generator to a high-pressure steam turbine or a high-pressure steam turbine section and / or a line configured to supply steam from the high-pressure steam turbine or a high-pressure steam turbine section to the heat recovery steam generator and / or a line configured to supply steam from the heat recovery steam generator to an intermediate-pressure steam turbine or an intermediate-pressure steam turbine section, or any possible combination thereof.

[0006] In yet another embodiment, a method may include: initiating a shutdown or partial load operation of a power plant having a gas turbine, a steam turbine, a heat recovery steam generator (HRSG), and a carbon capture system having separated materials; controlling the gas turbine to reduce to partial load conditions; controlling a first set of valves to at least partially close to reduce or disable steam flow to the steam turbine; and controlling a second set of valves connected to a standby line to enable or increase steam flow from the HRSG to the carbon capture system to perform a regeneration process on the separated materials. Attached Figure Description

[0007] These and other features, aspects, and advantages of the invention will be better understood when the following detailed description is read with reference to the accompanying drawings, in which the same reference numerals denote the same parts throughout the drawings, wherein:

[0008] Figure 1It is a block diagram of one implementation of a combined cycle system having one or more gas capture systems.

[0009] Figure 2 yes Figure 1 A schematic diagram of the implementation scheme of the combined cycle system, which further illustrates the gas turbine, heat recovery steam generator (HRSG), carbon capture system and steam turbine.

[0010] Figure 3 It is used to close Figure 1 A flowchart of an example method for a combined loop system.

[0011] Figure 4 It is used to close Figure 1 A flowchart of an example method for a combined loop system. Detailed Implementation

[0012] One or more specific embodiments of the present invention will now be described. To provide a concise description of these embodiments, not all features of the actual implementation may be described in the specification. It should be understood that, as in any engineering or design project, many implementation-specific decisions must be made in the development of any such implementation to achieve the developer's specific goals, such as complying with system-related and business-related constraints, which may vary from implementation to implementation. Furthermore, it should be understood that such development work may be complex and time-consuming, but remains a routine task of design, fabrication, and manufacturing for those skilled in the art who benefit from this disclosure.

[0013] When describing elements of various embodiments of the invention, the articles “a,” “an,” “the,” and “the” are intended to refer to one or more elements present in the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that additional elements may be present in addition to those listed.

[0014] The disclosed embodiments include systems and methods for improving carbon capture efficiency in combustion systems, such as combustion-driven power plants and / or combined cycle power plants having one or more gas capture systems. The gas capture system is configured to remove unwanted gases (e.g., carbon dioxide (CO2)) from the exhaust gas of the combustion system. In the disclosed embodiments, the combustion system includes a backup line configured to supply heated water and / or steam from a heat recovery steam generator (HRSG) to the gas capture system during shutdown operations of the combustion system. Therefore, the gas capture system can perform regeneration operations during shutdown operations and increase the amount of available separation material for subsequent combustion operations, which can improve carbon capture efficiency during subsequent start-up operations.

[0015] Figure 1This is a block diagram of one embodiment of a combined cycle system 10, which includes a gas turbine system 12, a steam turbine system 14, a heat recovery steam generator (HRSG) 16, a gas treatment system 18 with one or more gas trapping systems 20, and a controller 22 coupled to each of the systems 12, 14, 16, and 18. As described below, one or more gas trapping systems 20 of the gas treatment system 18 are configured to trap unwanted gases (e.g., CO2) from exhaust gas and / or air (e.g., direct air trapping), wherein heat (e.g., steam) is used in desorption mode during normal operation and shutdown operation of the combined cycle system 10. In some embodiments, during shutdown operation, the combined cycle system 10 is configured to supply heat (e.g., steam) to the gas treatment system 18 (e.g., gas trapping system 20) until the separation material (e.g., the adsorbent material of the adsorber and / or the solvent of the stripper) is substantially free of unwanted gases (e.g., CO2) to complete the regeneration of the separation material. For example, during shutdown operations, gas turbine system 12 can initiate a shutdown process to transition from full-load to partial-load conditions, steam turbine system 14 can initiate a shutdown process to close the main valve to stop steam supply to the steam turbine and open the bypass valve to bypass the steam turbine, and steam generated by HRSG 16 is supplied to gas processing system 18 (e.g., gas trapping system 20) to complete the regeneration of the separated material. Upon completion of regeneration, combined cycle system 10 can then continue and complete the shutdown process of gas turbine system 12. In other words, during partial-load conditions of gas turbine system 12, the regeneration of the separated material is achieved using steam from HRSG 16, thereby preparing gas trapping system 20 for subsequent startup operations.

[0016] Before discussing the details of the gas handling system 18, various aspects of the combined cycle system 10 will be discussed in further detail. For the purposes of orientation in the figures, reference may be made to the axial direction or axis 40, the radial direction or axis 42 extending radially away from the axial direction or axis 40, and the circumferential direction or axis 44 extending circumferentially around the axial direction or axis 40. For example, directions or axes 40, 42, and 44 may be referenced to the axis of rotation 36 of the gas turbine system 12.

[0017] The gas turbine system 12 includes an intake 50, a compressor 52 having one or more compressor stages, one or more combustors 54, a turbine 56 having one or more turbine stages, and a load 58 (e.g., a generator) driven by the turbine 56. In some embodiments, the gas turbine system 12 also includes an exhaust gas recirculation (EGR) system 60 configured to recirculate exhaust gas 62 back to the intake 50. Recirculating exhaust gas 62 helps reduce temperature and decrease certain emissions associated with combustion in the combustor 54 (e.g., nitrogen oxides (NOx)). XThe formation of the air supply and / or exhaust gas 62 is as follows: In operation, compressor 52 receives air from intake port 50 (and exhaust gas 62 if EGR system 60 is active), and compresses the air and / or exhaust gas 62 in one or more compressor stages (e.g., rotary compressor blade stages). Combustor 54 then burns fuel from the fuel supply system together with the compressed air and / or exhaust gas, generating hot combustion gases. The hot combustion gases expand and drive one or more turbine stages (e.g., rotary turbine blade stages) in turbine 56, thereby driving the rotation of compressor 52 and load 58 via shaft. Turbine 56 then outputs the hot combustion gases as exhaust gas 62.

[0018] HRSG 16 recovers waste heat from exhaust gas 62 to generate steam for driving steam turbine system 14. HRSG 16 includes a high-pressure (HP) steam section 70, an intermediate-pressure (IP) steam section 72, and a low-pressure (LP) steam section 74, configured to generate HP steam 76, IP steam 78, and LP steam 80. Steam turbine system 14 may include an HP steam turbine 82 driven by HP steam 76, an IP steam turbine 84 driven by IP steam 78, and an LP steam turbine 86 driven by LP steam 80. In addition to the steam supplied by HRSG 16, HP steam turbine 82 supplies IP steam to IP steam turbine 84, and IP steam turbine 84 supplies LP steam to LP steam turbine 86. LP steam turbine 86 then outputs any remaining steam / water to a condensate line 88 connected to the LP steam section 74 of HRSG 16. The condenser line 88 may include a condenser 90 and a pump 92, the condenser being configured to condense any remaining steam to form condensate, and the pump being configured to pump the condensate back to the LP steam section 74. In operation, the steam turbine system 14 drives a load 94 (e.g., a generator) via a shaft. In some embodiments, the steam turbine system 14 and / or HRSG 16 may supply heated water and / or steam (e.g., HP steam 76, IP steam 78, and / or LP steam 80) to the gas handling system 18 to support desorption modes (e.g., regeneration operations) of one or more gas trapping systems 20. In another example, the gas trapping system 20 may receive heated water and / or steam in temperature ranges of 100°C to 150°C, 110°C to 150°C, 120°C to 150°C, or 130°C to 150°C.

[0019] Following HRSG 16, exhaust gas 62 may flow to EGR system 60 and / or gas treatment system 18. In an illustrated embodiment, exhaust gas 62 flows through one or more gas trapping systems 20, which are configured to trap unwanted gases. Undesired gases may include carbon oxides (CO). X(For example, carbon dioxide (CO2) and carbon monoxide (CO)), nitrogen oxides (NO) X (For example, nitrogen dioxide (NO2)) sulfur oxides (SO4) X (e.g., sulfur dioxide (SO2)) or any combination thereof. In the discussion below, CO2 may be used as an example of an undesirable gas; however, the gas capture system 20 may be designed to capture any of the aforementioned undesirable gases. For example, the gas capture system 20 includes one or more carbon capture systems 100 (e.g., CO2 capture systems). The gas capture system 20 (e.g., carbon capture system 100) may include an adsorbent-based gas capture system, a solvent-based gas capture system, a cryogenic gas capture system, or any combination thereof configured to remove and capture undesirable gases. The carbon capture system 100 may include components 102, 104, 106, and 108 configured to achieve gas capture of undesirable gases (e.g., CO2) from exhaust gas 62, thereby outputting treated gas 110 and captured gas 112 (e.g., CO2). The treated gas 110 may be substantially free of undesirable gases (e.g., CO2) and may be discharged through an exhaust pipe. The captured gas 112 (e.g., CO2) can be compressed by compression system 114 and stored and / or transported by storage and / or pipeline system 116.

[0020] In some embodiments, carbon capture system 100 is an adsorbent-based carbon capture system, and components 102, 104, 106, and / or 108 include multiple adsorbent-based carbon capture units (e.g., adsorbers). For example, an adsorbent-based carbon capture unit may include a temperature-switching adsorption (TSA) unit or adsorber, wherein temperature fluctuations or variations are used to operate sequentially at different temperatures in an adsorption mode, a desorption mode, and a cooling mode. In adsorption mode, the adsorber is configured to adsorb an undesirable gas (e.g., CO2) into the adsorbent material at a first temperature. In desorption mode, the adsorber is configured to desorb the undesirable gas (e.g., CO2) from the adsorbent material, for example, by heating the adsorbent material from the first temperature to a higher second temperature using a heat source (e.g., regeneration of the adsorbent material). The heat source may include heated fluids, such as heated gases and / or liquids (e.g., steam). In the following discussion, the heat source includes steam from steam turbine system 14 and / or HRSG 16 during normal operation and / or shutdown operation of combined cycle power plant 10. Specifically, the combined cycle system 10 continues to supply steam during shutdown operations to complete the regeneration of the adsorbent material, for example, by continuing partial load conditions of the gas turbine system 12 to generate steam in the HRSG 16 to support the regeneration of the adsorbent material of the carbon capture system 100. In cooling mode, the adsorber is cooled in preparation for the next adsorption mode.

[0021] In some embodiments, carbon capture system 100 is a solvent-based carbon capture system, and components 102, 104, 106, and / or 108 include one or more adsorbers, strippers, and associated equipment. For example, the adsorber is configured to adsorb unwanted gases (e.g., CO2) into the solvent, thereby outputting treated gas 110 through an exhaust pipe and CO2-rich solvent to the stripper. The stripper is configured to apply heat to the CO2-rich solvent, thereby stripping unwanted gases (e.g., CO2) from the solvent to produce captured gas 112 and lean CO2 solvent (e.g., solvent regeneration). The stripper may receive heat via a heat source such as heated gas and / or liquid (e.g., steam). The stripper returns the lean CO2 solvent to the adsorber to repeat this cycle. In the following discussion, heat sources include steam from steam turbine system 14 and / or HRSG 16 during normal operation and / or shutdown operation of combined cycle power plant 10. Specifically, the combined cycle system 10 continues to supply steam during shutdown operations to complete solvent regeneration, for example by continuing partial load conditions of the gas turbine system 12 to generate steam in the HRSG 16 to support the regeneration of the solvent in the carbon capture system 100.

[0022] In the illustrated embodiment, controller 22 is configured to control all aspects of combined cycle system 10. Controller 22 includes one or more processors 120, memory 122, instructions 124 stored in memory 122 and executable by processor 120, and communication circuitry 126 configured to communicate with sensors and various equipment of combined cycle system 10. For example, controller 22 is configured to receive sensor feedback from sensors coupled to gas turbine system 12, steam turbine system 14, HRSG 16, and gas handling system 18 (e.g., gas capture system 20), and to control the same equipment based on that sensor feedback, operating mode, user input, computer model, or any combination thereof. Sensors may include temperature sensors, pressure sensors, flow rate sensors, gas composition sensors, or any combination thereof. In some embodiments, the controller 22 is configured to control the operation of the gas capture system 20 (e.g., carbon capture system 100), such as by controlling the operating mode (e.g., adsorption mode, desorption mode, and cooling mode), controlling the heat source for supplying heating fluid (e.g., steam) to the gas capture system 20, controlling the cooling source for supplying cooling fluid to the gas capture system 20, or any combination thereof.

[0023] For example, controller 22 can initiate a shutdown operation (e.g., a controlled shutdown operation) of combined cycle system 10. During the shutdown operation, for example, controller 22 can instruct gas turbine system 12 to operate at partial load (e.g., 30%, 40%, 50%, or 60% of full load) and output exhaust gas 62. Controller 22 can instruct steam turbine system 14 to shut down to isolate HRSG 16. Controller 22 can instruct HRSG 16 to generate steam 128 with exhaust gas 62 and instruct a set of valves 130 to open to supply steam 128 to gas capture system 20 (e.g., carbon capture system 100) to support desorption mode or regeneration of separation material (e.g., adsorbent material and / or solvent). Controller 22 can monitor gas capture system 20 to ensure completion of desorption mode. Controller 22 can determine the completion of desorption mode based on the elapsed time, a comparison between the concentration of unwanted gas within the separation material and a concentration range, or both. In response to completion, controller 22 may instruct the group of valves 130 to close, instruct HRSG 16 to stop generating steam 128, instruct the gas turbine system 12 to complete unloading, or any combination thereof. In this way, controller 22 can complete the shutdown operation.

[0024] Figure 2 This is a schematic diagram of a combined cycle system 10, which includes a gas turbine system 12, a steam turbine system 14, an HRSG 16, a gas handling system 18 with one or more carbon capture systems 100, and a controller 22 coupled to each of systems 12, 14, 16, and 18. In some cases, the carbon capture system 100 may be coupled to an auxiliary boiler 157, which provides additional steam to the carbon capture system 100. For example, the steam supply from the HRSG 16 may be less than a threshold steam supply, and the auxiliary boiler 157 may provide additional steam to facilitate the regeneration process of the carbon capture system 100. In some embodiments, the controller 22 is configured to control the steam supply from the HRSG 16 and the auxiliary boiler 157 to the carbon capture system 100 to complete the regeneration process during partial load operation and / or shutdown operation of the combined cycle system 10. Thus, the controller 22 can selectively enable, disable, increase, decrease, or any combination thereof to supply any amount of steam to the carbon capture system 100.

[0025] During combustion operation, the gas turbine system 12 may output exhaust gas 62, and the gas capture system 20 (e.g., carbon capture system 100) may perform adsorption operations to capture unwanted gases (e.g., CO2) from the exhaust gas 62. The exhaust gas 62 may also be supplied to the HRSG 16 for steam generation. The HRSG 16 may provide steam to drive the steam turbine system 14. For example, the HP steam section 70 of the HRSG 16 may supply HP steam 76 to the HP steam turbine 82 via the inlet of the HP steam turbine 82. The HP steam turbine 82 may supply HP return steam 150 via the outlet of the HP steam section 70, which directs the HP return steam 150 back to the HRSG 16. The IP steam section 72 of the HRSG 16 may supply IP steam 78 to the IP steam turbine 84 via the inlet of the IP steam turbine 84. The LP steam section 74 may receive steam from the IP steam turbine 84 and the LP steam section 74 of the HRSG 16 via the inlet of the LP steam turbine 86. The LP steam turbine 86 then outputs any remaining steam / water to a condensate line 88 connected to the LP steam section 74 of the HRSG 16. The condensate line 88 may include a condenser 90 configured to condense any remaining steam to form condensate, and a pump 92 configured to pump the condensate back to the LP steam section 74. In some cases, the steam turbine system 14 may supply heated water and / or steam to the carbon capture system 100 to support the desorption mode of the carbon capture system 100 (e.g., regeneration operation). Although the following discussion focuses on the carbon capture system 100, the illustrated embodiments are applicable to any type of gas capture system 20. As shown, for example, the LP steam turbine 86 may supply steam to the carbon capture system 100 via a main extraction line 152.

[0026] To facilitate the movement of steam between HRSG 16, steam turbine system 14, and carbon capture system 100, controller 22 can adjust the position of one or more valves (e.g., actuator-driven valves) within combined cycle system 10. For example, controller 22 can instruct a first set of valves 154 located between HRSG 16 and steam turbine system 14 to open to supply HP steam 76, IP steam 78, and / or LP steam 80 to steam turbine system 14. In another example, controller 22 can instruct a second set of valves 156 to open to supply LP steam 80 to carbon capture system 100. When the second set of valves 156 is instructed to open to supply LP steam 80 to main extraction line 152, controller 22 can instruct the first set of valves 154 to close. In yet another example, controller 22 can instruct a third valve 158 coupled to LP steam turbine 86 to adjust its position based on the direction of steam. For example, controller 22 may instruct third valve 158 to open in a first direction to supply LP steam 80 or steam from IP steam turbine 84 to LP steam turbine 86, and in a second direction to supply steam from LP steam turbine 86 to carbon capture system 100 via main extraction line 152.

[0027] After a period of time, controller 22 may initiate a controlled shutdown of combined cycle system 10. The controlled shutdown may initiate a load reduction of gas turbine system 12 from a first load condition (e.g., a large or full load condition) to a second load condition (e.g., a small or partial load condition), and may also shut off steam through steam turbines (e.g., HP steam turbine 82, IP steam turbine 84, and LP steam turbine 86) via the closure of the main valve and the opening of the bypass valve. For example, controller 22 may shut down steam turbine system 14 by instructing the closure of the first set of valves 154, the second set of valves 156, and the third valve 158 to isolate steam turbine system 14 from HRSG 16. When the valves reach their minimum positions (e.g., closed positions), steam turbine system 14 may trip and begin to decelerate. In other cases, controller 22 may instruct steam turbine system 14 to decelerate based on the indication of valve closure.

[0028] During a controlled shutdown of the combined cycle system 10, the controller 22 may instruct the gas turbine system 12 to operate at a reduced load (e.g., partial load conditions) for an extended period, thereby enabling the HRSG 16 to generate steam 128 for the regeneration operation of the carbon capture system 100. In other words, instead of immediately shutting down the gas turbine system 12, the gas turbine system 12 continues to operate at a reduced load to continue generating steam in the HRSG 16 to support the regeneration operation. For example, during a controlled shutdown, the controller 22 may instruct the gas turbine system 12 to change from full load conditions (e.g., 100% power output) to partial load conditions (e.g., less than or equal to 30%, 40%, 50%, or 60% power output) to continue delivering exhaust gas 62 to the HRSG 16 to generate steam 128. For example, during regeneration operation, the controller 22 may instruct the gas turbine system 12 to maintain partial load conditions at a constant load and / or a gradually decreasing load, while still enabling the HRSG 16 to generate sufficient steam 128 for the regeneration operation. In another example, controller 22 may instruct gas turbine system 12 to maintain minimum ambient load (MECL) so that HRSG 16 generates steam 128. Steam 128 may be residual steam generated when gas turbine system 12 operates under partial load conditions.

[0029] During shutdown operations, steam generated by HRSG 16 can be supplied to carbon capture system 100 via backup line 160. For example, backup line 160 can be located between HRSG 16 and steam turbine system 14. As shown, the inlet of backup line 160 can be located between HRSG 16 and HP steam turbine 82, and the outlet of backup line 160 can be located along main extraction line 152. Backup line 160 may include another inlet located between HRSG 16 and IP steam turbine 84. To supply steam 128, controller 22 can instruct a fourth set of valves 161 on backup line 160 to open. Therefore, steam 128 output from HRSG 16 (e.g., HP steam 76, IP steam 78) can be captured by backup line 160 and supplied to carbon capture system 100.

[0030] Steam 128 may include hot reheat steam and cold reheat steam. Hot reheat steam may include steam 128 extending from the outlet of IP steam turbine 84 along backup line 160 to carbon capture device 100. Cold reheat steam may include steam supplied from the outlet of HP steam return line 150 along additional backup line 167 to backup line 160 and to carbon capture device 100. Hot reheat steam may have a higher temperature than cold reheat steam.

[0031] The standby line 160 may include a fifth valve 162, which can be opened or closed based on the operation of the combined cycle system 10. For example, the controller 22 may instruct the fifth valve 162 to open during shutdown operations to supply steam along the standby line 160 and to close during combustion operations.

[0032] The backup line 160 may also include a first thermostat 164 configured to regulate or control the temperature of the steam 128. For example, the steam may travel along the backup line 160 in a temperature range of 300 to 500 degrees Celsius. To maintain the temperature of the steam 128 within this range, the first thermostat 164 along the backup line 160 receives water from a temperature-controlled water source 166 to regulate the temperature of the steam 128. For example, the temperature-controlled water source 166 may regulate the temperature of the steam 128 based on a temperature control setpoint, which may be determined based on a regeneration process. If the temperature of the steam 128 is higher than the temperature control setpoint, the temperature-controlled water source 166 may inject water along the backup line 160 into the thermostat 164 to lower the temperature of the steam 128.

[0033] Controller 22 can control the operation of the temperature-controlled water source 166 based on a temperature range. For example, controller 22 can monitor the temperature of steam 128 via one or more temperature sensors and instruct a sixth group of valves 168 to open or close based on a comparison between the temperature and a first temperature range. If the temperature of steam 128 is outside the first temperature range, controller 22 can instruct the sixth group of valves 168 to open to supply water from the temperature-controlled water source 166 to the first thermostat 164 to regulate the temperature of steam 128. If the temperature of steam 128 is within the first temperature range, controller 22 can instruct the sixth group of valves 168 to close or remain closed. If steam 128 exceeds an upper safety threshold (e.g., maximum steam pressure and / or maximum steam temperature), controller 22 can instruct a safety valve 170 along the backup line 160 to open and release steam pressure for safety reasons. Safety valve 170 may include a pressure relief valve.

[0034] The main extraction line 152 may include a second thermostat 174 configured to regulate or control the temperature of steam 128 along the main extraction line 152. For example, steam 128 may travel along the backup line 160 in a temperature range of 200 to 300 degrees Celsius. A controller 22 may monitor the temperature via one or more sensors and compare the temperature of steam 128 along the main extraction line 152 to a second temperature range. If the temperature of steam 128 is outside the second temperature range, the controller 22 may instruct a seventh set of valves 172 to open to inject water into the second thermostat 174 along the main extraction line 152 to regulate the temperature of steam 128. If the temperature of steam 128 is within the second temperature range, the controller 22 may instruct the seventh set of valves to close or remain closed. Steam 128 may be supplied from the main extraction line 152 to the carbon capture system 100 for regeneration operations.

[0035] The carbon capture system 100 can perform a regeneration operation using steam 128. The regeneration operation may include desorbing unwanted gases from the separation material by heating the separation material (e.g., the adsorbent material of an adsorber, the solvent of a stripper). For example, the carbon capture system 100 may use steam 128 to heat the adsorbent material from a first temperature to a higher second temperature to remove unwanted gases from the adsorbent material. In another example, the carbon capture system 100 may apply heat to a CO2-rich solvent to strip unwanted gases from the solvent to provide a CO2-lean solvent. The HRSG 16 may supply steam 128 to the carbon capture system 100 for any suitable period of time during shutdown operations (e.g., when the gas turbine system 12 is operating under partial load conditions and the steam turbine system 14 remains shut down). The controller 22 may monitor the completion of the regeneration operation. For example, the controller 22 may monitor the concentration of unwanted gases within the separation material, the amount of time taken to perform the regeneration operation, etc. In response to determining that the regeneration operation is complete, the controller 22 may continue the shutdown operation until completion. For example, controller 22 may instruct the fourth valve group 161, the fifth valve 162, or both to close to stop the supply of steam 128 to the carbon capture system 100. In another example, controller 22 may instruct the gas turbine system 12 to continue unloading and eventually shut down completely. Thus, controller 22 can complete the shutdown of the combined cycle system 10. By supplying steam 128 during the shutdown operation, the regeneration of the separated material can be completed, allowing the subsequent startup operation to begin carbon capture operations more quickly and efficiently. Therefore, the carbon capture rate of the combined cycle system 10 can be increased during the subsequent startup operation.

[0036] As discussed herein, valves may include any suitable valve for providing heated water and / or steam between the steam turbine system 14, HRSG 16, and carbon capture system 100. For example, valves may include check valves, two-way valves, ball valves, gate valves, butterfly valves, etc. Each valve may be coupled to an actuator (e.g., an electric actuator, pneumatic actuator, and / or hydraulic actuator) that controls the position of the valve. For example, the actuator may adjust the valve position between an open and closed position based on an instruction from controller 22.

[0037] Figure 3 It is used to make Figure 1 and Figure 2 A flowchart illustrating an implementation of the shutdown process 200 for the combined cycle system 10. In the illustrated implementation, process 200 may be partially or completely handled by... Figure 1 and Figure 2 The process 200 is controlled by controller 22. Process 200 includes initiating a controlled shutdown of power plant 10, which includes a gas turbine system 12, a steam turbine system 14, a heat recovery steam generator (HRSG) 16, and a carbon capture system 100 (box 202). Process 200 also controls valves to direct steam from HRSG 16 to carbon capture system 100 for regeneration during the controlled shutdown (box 204). For example, controller 22 may instruct a first set of valves 154, a second set of valves 156, and a third valve 158 to close to isolate steam turbine system 14 from HRSG 16. Controller 22 may also instruct a fourth set of valves 161 and a fifth valve 162 to open to supply steam 128 to carbon capture system 100. Then, after regeneration of carbon capture system 100 is complete, process 200 completes the controlled shutdown of power plant 10 (box 206). For example, controller 22 may instruct the fourth set of valves 161 and the fifth valve 162 to close to stop supplying steam 128 to the carbon capture system 100, instruct the gas turbine system 12 to continue unloading and shut down completely, or both. Thus, controller 22 can complete the controlled shutdown of the combined cycle system 10 after the separated material in the carbon capture system 100 has been fully regenerated.

[0038] Figure 4 It is used to close Figure 1 and Figure 2 A flowchart of an embodiment of process 240 of the combined cycle system 10. In the illustrated embodiment, process 240 may be partially or completely... Figure 1 and Figure 2The process 240 is controlled by controller 22. Process 240 includes initiating a controlled shutdown of the power plant 10, which includes a gas turbine system 12, a steam turbine system 14, a heat recovery steam generator (HRSG) 16, and a carbon capture system 100 (box 242). Process 240 also controls the gas turbine system 12 to be reduced to partial load conditions (box 244). In some cases, the gas turbine system 12 may operate at full load. In other cases, the gas turbine system 12 may operate at partial load conditions less than full load conditions, such as less than or equal to 30%, 40%, 50%, or 60% of full load conditions. Process 240 then controls the valves of the steam turbine system 14 to close to initiate a shutdown of the steam turbine system 14 (box 246). For example, controller 22 may instruct a first set of valves 154 to close to isolate the steam turbine system 14 from the HRSG 16. Process 240 may also shut down the steam turbine system 14 after closing the valves (box 248). Process 240 controls a valve to direct steam from HRSG 16 to supply steam to carbon capture system 100 (box 250). For example, controller 22 may instruct a valve to open to direct steam 128 from HRSG 16 to carbon capture system 100 via backup line 160. Process 240 also controls carbon capture system 100 to regenerate using steam 128 from HRSG 16 (box 252). For example, controller 22 may instruct carbon capture system 100 to operate in desorption mode using steam 128 (e.g., perform a regeneration operation). Process 240 may monitor the completion of regeneration of carbon capture system 100 (box 254). For example, controller 22 may determine completion based on the elapsed time, the concentration of unwanted gases within the separated material, or both. Process 240 then controls a valve to stop (e.g., close) the flow of steam 128 from HRSG 16 to carbon capture system 100 during regeneration competition (box 256). For example, controller 22 can instruct the valve to close to stop the flow of steam from HRSG 16 to carbon capture system 100. Process 240 can also control the gas turbine system 12 to continue unloading to complete a controlled shutdown of the power plant (box 258).

[0039] The technical effect of the disclosed embodiments is to provide steam during shutdown processes to improve gas capture by adsorbent-based gas capture (e.g., carbon capture of CO2) systems or solvent-based gas capture systems. During shutdown processes, for example, the gas turbine may operate under load (e.g., partial load) and output exhaust gas, allowing the HRSG to continue outputting steam. Steam can be supplied to the gas capture system via a standby line for regeneration processes. For example, steam can strip unwanted gases (e.g., CO2) from a CO2-rich solvent and increase the total CO2 captured at the gas capture system before a complete shutdown. In another example, steam can desorb unwanted gases (e.g., CO2) from the adsorbent material, thereby regenerating the adsorbent material. Providing steam to the gas capture system can increase the amount of lean CO2 solvent and / or lean CO2 adsorbent material available for carbon capture during subsequent startup operations. Therefore, due to the leaner solvent and / or the increased amount of available adsorbent material, the disclosed embodiments can provide an increased CO2 capture rate during the next startup process.

[0040] As illustrated below, the subject matter described in the detailed description above may be defined by one or more clauses.

[0041] A system comprising: a gas capture system including a separation material, wherein the gas capture device is configured to operate a regeneration process during partial load operation and / or shutdown operation to desorb unwanted gases from the separation material to deplete the separation material for the absorption process; a heat recovery steam generator (HSRG) configured to receive waste gas and generate steam; and a backup line fluidly connecting the gas capture system to the HRSG, wherein the backup line is configured to supply the steam from the HRSG to the gas capture system for the regeneration process during the partial load operation and / or the shutdown operation.

[0042] A system as described in or in combination with the foregoing clauses and / or any of the appended claims, wherein the system includes a main extraction line fluidly connected to or branching from the heat recovery steam generator and configured to supply steam from the heat recovery steam generator to the gas capture system, and wherein a backup line is also fluidly connected to or branching from the heat recovery steam generator at at least one steam extraction location, the at least one steam extraction location providing a higher steam pressure than the steam extraction locations where the main extraction line is connected to or branching from the heat recovery steam generator. For example, the main extraction line may branch off from a line configured to supply steam to a low-pressure steam turbine or a low-pressure steam turbine section, while the backup line may branch off from a line configured to supply high-pressure steam from a heat recovery steam generator to a high-pressure steam turbine or a high-pressure steam turbine section and / or a line configured to supply steam from a high-pressure steam turbine or a high-pressure steam turbine section to a heat recovery steam generator and / or a line configured to supply steam from a heat recovery steam generator to an intermediate-pressure steam turbine or an intermediate-pressure steam turbine section, or any possible combination thereof.

[0043] The system as described in any of the foregoing clauses and / or any of the appended claims, or in combination with any of the foregoing clauses and / or any of the appended claims, includes a gas turbine system configured to output the exhaust gas during the partial load operation and / or the shutdown operation.

[0044] The system, as described in any of the foregoing clauses and / or any of the appended claims, or in combination with any of the foregoing clauses and / or any of the appended claims, comprises: a thermostat connected to the backup pipeline, wherein the thermostat is configured to control the temperature of the steam along the backup pipeline; a pressure reducing valve for controlling the pressure of the steam used in the regeneration process; and a safety valve connected to the backup pipeline, wherein the safety valve is configured to release the steam when the steam pressure exceeds a pressure threshold.

[0045] The system, as described in any of the foregoing clauses and / or any of the appended claims, or in combination with any of the foregoing clauses and / or any of the appended claims, includes a temperature-controlled water source configured to inject water into the thermostat along the backup pipeline based on the temperature of the steam being greater than a temperature control setpoint for the regeneration process.

[0046] The system as described in any of the foregoing clauses and / or any of the appended claims, or in combination with any of the foregoing clauses and / or any of the appended claims, wherein the backup line is configured to supply the steam to the main extraction line fluidly connected to the gas capture system.

[0047] The system as described in any of the foregoing clauses and / or any of the appended claims, or in combination with any of the foregoing clauses and / or any of the appended claims, wherein the main extraction line includes a thermostat configured to control the temperature of the steam along the main extraction line.

[0048] The system, as described in any of the foregoing clauses and / or any of the appended claims, or in combination with any of the foregoing clauses and / or any of the appended claims, includes a temperature-controlled water source configured to inject water into the thermostat along the main extraction line based on the temperature of the steam being greater than a temperature control setpoint for the regeneration process.

[0049] A system as described in any of the foregoing clauses and / or any of the appended claims, or in combination with any of the foregoing clauses and / or any of the appended claims, the system comprising a steam turbine fluidly coupled to the HRSG via a set of valves, and a controller communicatively coupled to the set of valves, wherein the controller is configured to control each of the set of valves to at least partially close based on receiving an instruction to initiate the partial load operation and / or the shutdown operation.

[0050] The system as described in any of the foregoing clauses and / or any of the appended claims, or in combination with any of the foregoing clauses and / or any of the appended claims, wherein the controller is configured to monitor the regeneration process of the gas trapping system and the steam from the HRSG, and to begin supplying steam from an additional steam supply source to support the regeneration process of the gas trapping system based on the fact that the amount of steam from the HRSG is less than a threshold steam supply.

[0051] The system as described in any of the foregoing provisions and / or any of the appended claims, or in combination with any of the foregoing provisions and / or any of the appended claims, wherein the additional steam supply source includes an auxiliary boiler.

[0052] A system may include a power plant comprising a gas turbine configured to output exhaust gas, a heat recovery steam generator (HRSG) configured to receive the exhaust gas and output steam, and a steam turbine configured to receive the steam. The system may also include a carbon capture system and a controller configured to capture unwanted gases from the exhaust gas in a separation material, the controller being configured to initiate partial load operation and / or shutdown operation of the power plant. The controller may control the gas turbine to reduce to partial load conditions and continue outputting the exhaust gas, control a first set of valves to at least partially close to reduce or disable the steam flow to the steam turbine, and control a second set of valves to enable or increase the steam flow from the HRSG to the carbon capture system via a backup line for a period of time to perform a regeneration process on the separation material. More specifically, the system may include a main extraction line fluidly connected to or branching from the heat recovery steam generator and configured to supply steam from the heat recovery steam generator to the gas capture system. The backup line is also fluidly connected at least at a steam extraction location to or branching from a heat recovery steam generator, thereby providing a higher steam pressure than at the steam extraction locations where the main extraction line is connected to or branching from the heat recovery steam generator. For example, the main extraction line may branch from a line configured to supply steam to a low-pressure steam turbine or a low-pressure steam turbine section, while the backup line may branch from a line configured to supply high-pressure steam from the heat recovery steam generator to a high-pressure steam turbine or a high-pressure steam turbine section and / or a line configured to supply steam from the high-pressure steam turbine or a high-pressure steam turbine section to the heat recovery steam generator and / or a line configured to supply steam from the heat recovery steam generator to an intermediate-pressure steam turbine or an intermediate-pressure steam turbine section, or any possible combination thereof.

[0053] A system as described in any of the foregoing clauses and / or any of the appended claims, or in combination with any of the foregoing clauses and / or any of the appended claims, wherein the controller is configured to control the carbon capture system to perform the regeneration process using the steam from the HRSG.

[0054] The system as described in any of the foregoing clauses and / or any of the appended claims, or in combination with any of the foregoing clauses and / or any of the appended claims, wherein the controller is configured to control the second set of valves to close to stop the steam from the HRSG to the carbon capture system based on the completion of the regeneration process or based on a change from the HRSG to an additional steam supply source for completing the regeneration process.

[0055] A system as described in any of the foregoing clauses and / or any of the appended claims, or in combination with any of the foregoing clauses and / or any of the appended claims, wherein the controller is configured to control an additional steam supply source to begin supplying steam to support the regeneration process of the carbon capture system based on the steam supply from the HRSG being less than a threshold steam supply.

[0056] The system comprises temperature-regulating water configured to be injected into a thermostat along the backup pipeline based on the temperature of the steam along the backup pipeline being greater than a temperature control setpoint for the regeneration process.

[0057] The system as described in any of the foregoing clauses and / or any of the appended claims, or in combination of any of the foregoing clauses and / or any of the appended claims, wherein the controller is configured to control the second set of valves to direct the steam from the high-pressure (HP) steam section of the HRSG, the medium-pressure (IP) steam section of the HRSG, or a combination thereof to the carbon capture system during the regeneration process.

[0058] The system as described in any of the foregoing clauses and / or any of the appended claims, or in combination with any of the foregoing clauses and / or any of the appended claims, wherein the separating material comprises an adsorbent material or a solvent.

[0059] One method may include: initiating a shutdown or partial load operation of a power plant having a gas turbine, a steam turbine, a heat recovery steam generator (HRSG), and a carbon capture system having separated materials; controlling the gas turbine to reduce to partial load conditions; controlling a first set of valves to close at least partially to reduce or disable steam flow to the steam turbine; and controlling a second set of valves connected to a standby line to enable or increase the steam flow from the HRSG to the carbon capture system to perform a regeneration process on the separated materials.

[0060] The method as described in or in combination with any of the foregoing clauses and / or any of the appended claims, the method further comprising: monitoring the carbon capture system during the regeneration process; controlling the second set of valves to stop directing the steam to the carbon capture system based on the detection that the carbon capture system has completed the regeneration process; and controlling the gas turbine to continue unloading to complete the shutdown operation of the power plant.

[0061] The method as described in or in combination with any of the foregoing clauses and / or any of the appended claims, the method further comprising: controlling the steam supply from an additional steam supply source to support the regeneration process of the carbon capture system based on the steam supply from the HRSG being less than a threshold steam supply.

[0062] This written description uses examples to disclose the invention, including the best mode, and also enables any person skilled in the art to practice the invention, including making and using any device or system and performing any combination of methods. The scope of the invention claimed herein is defined by the appended claims and may include other examples besides those provided in the foregoing description that would occur to a person skilled in the art.

Claims

1. A system comprising: A gas capture system (20) includes a separation material, wherein the gas capture system is configured to capture unwanted gases from exhaust gas in the separation material and to operate a regeneration process to desorb unwanted gases from the separation material, thereby regenerating the separation material for use in an absorption process; A heat recovery steam generator (16) is configured to receive the waste gas and generate steam. and A backup line (160) fluidly connects the gas trapping system (20) to the heat recovery steam generator (16), wherein the backup line is configured to supply steam from the heat recovery steam generator to the gas trapping system for the regeneration process during partial load operation and / or shutdown operation.

2. The system of claim 1, wherein the spare (160) line is fluidly connected to the high-pressure steam section (70) of the heat recovery steam generator, the medium-pressure steam section (72) of the heat recovery steam generator, or a combination thereof, and is configured to supply steam from the heat recovery steam generator to the gas capture system for the regeneration process from the high-pressure steam section of the heat recovery steam generator, the medium-pressure steam section of the heat recovery steam generator, or a combination thereof.

3. The system according to any of the preceding claims, wherein the system comprises: A thermostat (164) is connected to the backup line, wherein the thermostat is configured to control the temperature of the steam flowing along the backup line; Pressure reducing valve (162), the pressure reducing valve being used to control the pressure of the steam supplied from the backup line to the gas capture system; and A safety valve (170) is connected to the backup line, wherein the safety valve is configured to release steam when the steam pressure of the steam supplied from the backup line to the gas trapping system exceeds a pressure threshold.

4. The system according to any of the preceding claims, wherein the backup line is configured to supply the steam to the main extraction line (152) fluidly connected to the gas capture system.

5. The system of claim 4, wherein the main extraction line includes a thermostat (174) configured to control the temperature of the steam flowing along the main extraction line.

6. The system according to any of the preceding claims, wherein the system further comprises: Gas turbine (12), which outputs the exhaust gas; A steam turbine (14), fluidly connected to the heat recovery steam generator (16), and configured to receive steam from the heat recovery steam generator, Controller (22), the controller being configured to initiate the partial load operation and / or shutdown operation of the power plant, including the gas turbine, the steam turbine, the heat recovery steam generator and the gas trapping system, in such a manner as: Control (244) the gas turbine to reduce to partial load conditions and continue to output the exhaust gas; and At least one of the following: for a period of time, activating or increasing the steam flow from the heat recovery steam generator to the gas trapping system via the backup pipeline to perform a regeneration process on the separated material.

7. The system of claim 6, wherein the controller is configured to reduce or disable the steam flow from the heat recovery steam generator to the steam turbine.

8. The system according to any one of claims 6 or 7, wherein the controller is configured to: control (246) at least partially close a first set of valves to reduce or disable the steam flow to the steam turbine, and / or control (250) a second set of valves coupled to the backup line to enable or increase the steam flow from the heat recovery steam generator to the gas trapping system through the backup line.

9. The system according to any one of claims 6 to 8, wherein the controller is configured to: The control (252) gas capture system uses steam from the heat recovery steam generator to perform the regeneration process. During the time period, monitor (254) the regeneration process of the gas capture system, and Based on the completion of the regeneration process or based on the change from the heat recovery steam generator to an additional steam supply source for the completion of the regeneration process, the steam flow from the heat recovery steam generator to the gas capture system is stopped (256).

10. A method, the method comprising: Start-up (242) of a power plant with a gas turbine (12), a steam turbine (14), a heat recovery steam generator (16) and a gas capture system (20) with separation material; Control (244) the gas turbine to reduce to partial load conditions; as well as The steam flow from the heat recovery steam generator to the gas trapping system is activated or increased via a backup pipeline to perform a regeneration process on the separated material.

11. The method of claim 10, wherein the method comprises at least one of: reducing or disabling the steam flow from the heat recovery steam generator to the steam turbine.

12. The method according to any one of claims 10 or 11, the method comprising at least one of: controlling (246) a first set of valves to at least partially close to reduce or disable the steam flow to the steam turbine, and / or controlling (250) a second set of valves connected to the backup line to enable or increase the steam flow through the backup line from the heat recovery steam generator to the gas trapping system.

13. The method according to any one of claims 10 to 12, the method further comprising: The gas capture system (254) is monitored during the regeneration process; Based on the detection that the gas trapping system has completed the regeneration process, the flow of steam into the gas trapping system is stopped (256); and Control (258) the gas turbine to continue unloading to complete the shutdown operation of the power plant. Specifically, stopping the flow of steam into the gas capture system includes controlling a second set of valves.

14. The method according to any one of claims 10 to 13, the method further comprising controlling the steam supply from an additional steam supply source to support the regeneration process of the gas trapping system based on the steam supply from the heat recovery steam generator being less than a threshold steam supply.

15. The system according to any one of claims 1 to 9, the system further comprising a controller (22) configured to perform the method according to any one of claims 10 to 14.

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