System and method for supplying vapor to a gas capture system during shutdown

Abstract

This invention provides a system and method for supplying steam to a gas capture system during shutdown. [Solution] The system may include a gas capture system containing separation material, wherein the gas capture system is configured to operate a regeneration process during partial load operation and / or shutdown operation for desorbing undesirable gases from the separation material and regenerating the separation material for an absorption process; a heat recovery steam generator (HRSG) configured to receive exhaust gas and generate steam; and a backup line fluidly coupling 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.

Description

[Technical Field]

[0001] The present application generally relates to systems and methods for steam supply to a gas capture system during controlled shutdown operation of combustion systems, such as combustion-driven power plants. The invention claimed herein relates to the subject-matter set forth in the appended claims. [Background Art]

[0002] Industrial plants, such as combustion-driven power plants, may generate various 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 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 (SO X ), such as sulfur dioxide (SO2). In certain cases, a combustion-driven power plant may include a gas capture system that enables capture of undesirable gases during operation of the combustion-driven power plant. The gas capture system may perform a regeneration operation to remove (e.g., strip, desorb) undesirable gases from separation material (e.g., adsorbent material in an adsorber and / or solvent in a stripper), such as by applying heat to the separation material. Unfortunately, during shutdown operation of a combustion-driven power plant, regeneration of the separation material is generally incomplete due to insufficient heat. As a result, during subsequent start-up operation of the combustion-driven power plant, the previous incomplete regeneration of the separation material leads to reduced gas capture efficiency in the gas capture system. Accordingly, a need exists for improving regeneration during shutdown operation, such as by supplying additional heat to complete regeneration. [Summary of the Invention]

[0003] The invention claimed herein is described in the appended claims. Specific embodiments corresponding to the scope of the originally claimed subject matter are summarized below. These embodiments are not intended to limit the scope of the claimed subject matter, but rather to provide an overview of possible forms of the subject matter. Indeed, the subject matter may encompass a variety of forms, which may be similar to or different from the embodiments described below.

[0004] In one embodiment, the system may include a gas capture system containing separation material, the gas capture system configured to operate a regeneration process during partial load operation and / or shutdown operation for desorbing undesirable gases from the separation material and regenerating the separation material for an absorption process; a heat recovery steam generator (HRSG) configured to receive exhaust gas and generate steam; and a backup line fluid-coupled the gas capture system to the HRSG, the backup line 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 fluid-coupled to or branching off 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 fluid-coupled to or branching off 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 coupled to or branching off 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, and 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.

[0005] In another embodiment, the system may include a plant comprising a gas turbine configured to output exhaust gases, a heat recovery steam generator (HRSG) configured to receive exhaust gases and output steam, and a steam turbine configured to receive steam. The system may also include a carbon capture system configured to capture undesirable gases from the exhaust gases in the separation material, and a controller configured to initiate partial load operation and / or shutdown operation of the plant. The controller may control the gas turbine to reduce to a partial load state and continue outputting exhaust gases, control a first set of valves to at least partially close to reduce or disable the flow of steam to the steam turbine, and control a second set of valves to allow or increase the flow of steam from the HRSG to the carbon capture system via a backup line to perform a regeneration process on the separation material. Similar to the embodiments outlined above, the system may more specifically include a main extraction line that is fluid-coupled to or branched off from the heat recovery steam generator and configured to supply steam from the heat recovery steam generator to the gas capture system. The backup lines are also fluidly coupled to or branch off from the heat recovery steam generator at at least one steam extraction location, and this at least one steam extraction location provides a higher steam pressure than the steam extraction locations where the main extraction lines are coupled to or branch off from the heat recovery steam generator. For example, the main extraction lines may branch off from lines configured to supply steam to a low-pressure steam turbine or a low-pressure steam turbine section, and the backup lines may branch off from lines 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 lines 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 lines 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, the method may include initiating a shutdown or partial load operation of a plant having a gas turbine, a steam turbine, a heat recovery steam generator (HRSG), and a carbon capture system having separation material; controlling the gas turbine to reduce to a partial load state; controlling a first set of valves to at least partially close in order to reduce or disable the flow of steam to the steam turbine; and controlling a second set of valves coupled to a backup line to allow or increase the flow of steam from the HRSG to the carbon capture system in order to carry out a regeneration process on the separation material.

[0007] These and other features, aspects, and advantages of the present invention will be better understood by reading the following embodiments for carrying out the invention with reference to the accompanying drawings, where similar reference numerals throughout the drawings represent similar parts. [Brief explanation of the drawing]

[0008] [Figure 1] This is a block diagram of one embodiment of a combined cycle system having one or more gas capture systems. [Figure 2] Figure 1 is a schematic diagram of one embodiment of the combined cycle system, further showing a gas turbine, a heat recovery steam generator (HRSG), a carbon capture system, and a steam turbine. [Figure 3] Figure 1 is a flowchart illustrating an exemplary method for shutting down the combined cycle system. [Figure 4] Figure 1 is a flowchart illustrating an exemplary method for shutting down the combined cycle system. [Modes for carrying out the invention]

[0009] One or more specific embodiments of the present invention are described below. Not all features of actual implementations are described herein in order to provide a concise description of these embodiments. It should be understood that in developing such actual implementations, as with any engineering or design project, a number of implementation-specific decisions must be made to achieve the developer's specific goals, including compliance with system-related and business-related constraints, which may differ from implementation to implementation. Furthermore, it should be understood that such development efforts, while complex and time-consuming, are still routine design, fabrication, and manufacturing tasks for those skilled in the art who are interested in this disclosure.

[0010] When describing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” indicate that one or more of the elements exist. The terms “comprising,” “including,” and “having” are intended to be comprehensive and indicate that additional elements other than those listed may exist.

[0011] The disclosed embodiments include systems and methods for improving the carbon capture rate of a combustion system, such as a combustion-driven power plant and / or a combined-cycle power plant, having one or more gas capture systems. The gas capture systems are configured to remove undesirable gases (e.g., carbon dioxide (CO2)) from the exhaust gases 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 a shutdown operation of the combustion system. Thus, the gas capture system may perform a regeneration operation during the shutdown operation, increasing the amount of separation material available for subsequent combustion operations, which may improve the carbon capture rate during subsequent start-up operations.

[0012] Figure 1 is a block diagram of one embodiment of a combined cycle system 10 having a gas turbine system 12, a steam turbine system 14, a heat recovery steam generator (HRSG) 16, a gas treatment system 18 having one or more gas capture systems 20, and a controller 22 coupled to each of systems 12, 14, 16, and 18. As described below, one or more gas capture systems 20 of the gas treatment system 18 are configured to capture undesirable gases (e.g., CO2) from exhaust gas and / or air (e.g., direct air capture), and heat (e.g., steam) is used for desorption modes during both normal operation and shutdown operation of the combined cycle system 10. In a particular embodiment, 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 capture system 20) until the separation material (e.g., adsorbent material in the adsorber and / or solvent in the stripper) substantially no longer contains undesirable gases (e.g., CO2) in order to complete the regeneration of the separation material. For example, during a shutdown operation, the gas turbine system 12 may initiate a shutdown procedure to transition from a full load state to a partial load state, and the steam turbine system 14 may initiate a shutdown procedure to close the main valve to stop the supply of steam to the steam turbine and open the bypass valve to bypass the steam turbine, and the steam generated by the HRSG 16 is supplied to the gas processing system 18 (e.g., the gas capture system 20) to complete the regeneration of the separation material. Once regeneration is complete, the combined cycle system 10 may continue and complete the shutdown procedure of the gas turbine system 12. In other words, while the gas turbine system 12 is in a partial load state, the steam from the HRSG 16 is used to achieve the regeneration of the separation material, thereby preparing the gas capture system 20 for the subsequent start-up operation.

[0013] Before describing the details of the gas processing system 18, various embodiments of the combined cycle system 10 will be described in more detail. For the purpose of orientation in the drawings, the axial or axis 40, the radial or axis 42 extending radially away from the axial or axis 40, and the circumferential or axis 44 extending circumferentially around the axial or axis 40 may be referenced. The directions or axes 40, 42, and 44 may be, for example, based on the rotation axis 36 of the gas turbine system 12.

[0014] The gas turbine system 12 includes an intake port 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 certain embodiments, the gas turbine system 12 further includes an exhaust gas recirculation (EGR) system 60 configured to recirculate exhaust gas 62 to the intake port 50. The recirculated exhaust gas 62 is free from certain emissions associated with combustion in the combustors 54 (e.g., nitrogen oxides (NOx)). X This helps to reduce the temperature and formation of the )). During operation, the compressor 52 receives air (and exhaust gas 62 if the EGR system 60 is operating) from the intake port 50 and compresses the air and / or exhaust gas 62 in one or more compressor stages (e.g., stages of the rotary compressor blades). The combustor 54 then burns the fuel from the fuel supply system with the compressed air and / or exhaust gas to generate hot combustion gases. The hot combustion gases expand to drive one or more turbine stages (e.g., stages of the rotary turbine blades) in the turbine 56, thereby driving the rotation of the compressor 52 and load 58 via the shaft. The turbine 56 then outputs the hot combustion gases as exhaust gas 62.

[0015] The HRSG16 recovers waste heat from exhaust gas 62 to generate steam for driving the steam turbine system 14. The HRSG16 includes an HP steam section 70, an IP steam section 72, and an LP steam section 74 configured to generate high-pressure (HP) steam 76, medium-pressure (IP) steam 78, and low-pressure (LP) steam 80. The 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 the HRSG16, the HP steam turbine 82 supplies IP steam to the IP steam turbine 84, and the IP steam turbine 84 supplies LP steam to the LP steam turbine 86. The LP steam turbine 86 then outputs the remaining steam / water to a condensate line 88 connected to the LP steam section 74 of the HRSG16. The condensation line 88 may include a condenser 90 configured to condense the remaining steam to form a condensate, and a pump 92 configured to pump the condensate back to the LP steam section 74. During operation, the steam turbine system 14 drives a load 94 (e.g., a generator) via a shaft. In certain 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 processing system 18 to support the desorption modes (e.g., regeneration operation) of one or more gas capture systems 20. In another example, the gas capture system 20 may receive heated water and / or steam in a temperature range of 100-150 degrees Celsius, 110-150 degrees Celsius, 120-150 degrees Celsius, or 130-150 degrees Celsius.

[0016] After HRSG16, the exhaust gas 62 may flow into the EGR system 60 and / or the gas treatment system 18. In the illustrated embodiment, the exhaust gas 62 flows through one or more gas capture systems 20 configured to capture undesirable gases. Undesirable gases include carbon oxides (CO2). X (For example, carbon dioxide (CO2) and carbon monoxide (CO), nitrogen oxides (NO)X (For example, nitrogen dioxide (NO2), sulfur oxides (SO2)) X This may include (e.g., sulfur dioxide (SO2)), or any combination thereof. In the following description, CO2 may be used as an example of an undesirable gas, but 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., a CO2 capture system). The gas capture system 20 (e.g., a 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 the undesirable gas. The carbon capture system 100 may include components 102, 104, 106, and 108 configured to enable gas capture of undesirable gases (e.g., CO2) from the exhaust gas 62, thereby outputting a treated gas 110 and a captured gas 112 (e.g., CO2). The treated gas 110 may not substantially contain the undesirable gases (e.g., CO2) and may be discharged through the exhaust stack. The captured gas 112 (e.g., CO2) can be compressed by a compression system 114 and stored and / or transported by a storage and / or pipeline system 116.

[0017] In certain embodiments, the carbon capture system 100 is an adsorbent-based carbon capture system, and components 102, 104, 106, and / or 108 include a plurality of adsorbent-based carbon capture units (e.g., adsorbers). For example, the adsorbent-based carbon capture units may include temperature swing adsorption (TSA) units or adsorbers, and temperature swings or changes are used to sequentially operate in adsorption mode, desorption mode, and cooling mode at various temperatures. In adsorption mode, the adsorber is configured to adsorb an undesirable gas (e.g., CO2) onto an 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 by heating the adsorbent material from a first temperature to a higher second temperature using a heat source (e.g., regeneration of the adsorbent material). The heat source may include heated gases and / or heated fluids such as liquids (e.g., steam). In the following description, the heat source includes steam from the steam turbine system 14 and / or HRSG 16 during normal operation and / or shutdown operation of the combined cycle plant 10. In particular, the combined cycle system 10 continues to supply steam to complete the regeneration of adsorbent material during shutdown operation, for example by maintaining a partial load state of the gas turbine system 12 to generate steam in the HRSG 16 to support the regeneration of adsorbent material in the carbon capture system 100. In cooling mode, the adsorber is cooled in preparation for the next adsorption mode.

[0018] In certain embodiments, the carbon capture system 100 is a solvent-based carbon capture system, and components 102, 104, 106, and / or 108 include one or more absorbers, strippers, and associated equipment. For example, an absorber is configured to absorb an undesirable gas (e.g., CO2) into a solvent, thereby outputting the treated gas 110 through an exhaust stack and outputting the CO2-rich solvent to a stripper. A stripper is configured to heat the CO2-rich solvent, thereby stripping the undesirable gas (e.g., CO2) from the solvent to produce a captured gas 112 and a CO2-dilute solvent (e.g., solvent regeneration). The stripper may accept heat via a heat source such as a heated gas and / or liquid (e.g., vapor). The stripper returns the CO2-dilute solvent to the absorber to repeat the cycle. In the following description, the heat source includes steam from the steam turbine system 14 and / or HRSG 16 during normal operation and / or shutdown operation of the combined cycle plant 10. In particular, the combined cycle system 10 continues to supply steam to complete solvent regeneration during shutdown operation, for example by maintaining a partial load state 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.

[0019] In the illustrated embodiment, the controller 22 is configured to control all aspects of the combined cycle system 10. The controller 22 includes one or more processors 120, a memory 122, instructions 124 stored in the memory 122 and executable by the processors 120, and a communication circuit 126 configured to communicate with sensors and various devices of the combined cycle system 10. For example, the controller 22 receives sensor feedback from sensors coupled to the gas turbine system 12, steam turbine system 14, HRSG 16, and gas processing system 18 (e.g., gas capture system 20), and is configured to control the same devices based on sensor feedback, operating mode, user input, computer model, or any combination thereof. The sensors may include temperature sensors, pressure sensors, flow sensors, gas composition sensors, or any combination thereof. In certain embodiments, the controller 22 is configured to control the operation of the gas capture system 20 (e.g., carbon capture system 100) by controlling the operating modes (e.g., adsorption mode, desorption mode, and cooling mode), controlling the heat source for supplying heated fluid (e.g., steam) to the gas capture system 20, controlling the cooling source for supplying cooled fluid to the gas capture system 20, or any combination thereof.

[0020] For example, the controller 22 may initiate a shutdown operation of the combined cycle system 10 (e.g., a controlled shutdown operation). During the shutdown operation, for example, the controller 22 may instruct the gas turbine system 12 to operate at partial load (e.g., 30, 40, 50, or 60% of full load) and output exhaust gas 62. The controller 22 may instruct the steam turbine system 14 to shut down in order to isolate the HRSG 16. The controller 22 may instruct the HRSG 16 to generate steam 128 in the exhaust gas 62 to support a desorption or regeneration mode of the separation material (e.g., adsorbent material and / or solvent), and may instruct the valve set 130 to open to supply the steam 128 to the gas capture system 20 (e.g., a carbon capture system 100). The controller 22 may monitor the gas capture system 20 for the completion of the desorption mode. The controller 22 may determine the completion of the desorption mode based on the passage of time, a comparison between the concentration of undesirable gas in the separation material and a concentration range, or both. In response to completion, the controller 22 may instruct the valve set 130 to close in order for the HRSG 16 to stop generating steam 128, the gas turbine system 12 to complete load reduction, or any combination thereof. Thus, the controller 22 may complete the shutdown operation.

[0021] Figure 2 is a schematic diagram of a combined cycle system 10 comprising a gas turbine system 12, a steam turbine system 14, an HRSG 16, a gas processing system 18 including one or more carbon capture systems 100, and a controller 22 coupled to each of the systems 12, 14, 16, and 18. In certain examples, the carbon capture system 100 may be coupled to an auxiliary boiler 157 that supplies 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 supply additional steam to facilitate the regeneration process of the carbon capture system 100. In certain embodiments, the controller 22 is configured to control steam supply from the HRSG 16 and the auxiliary boiler 157 to the carbon capture system 100 so as to complete the regeneration process during partial load operation and / or shutdown operation of the combined cycle system 10. Accordingly, the controller 22 may selectively enable, disable, increase the flow of, decrease the flow of, or any combination thereof, any number of steam supplies to the carbon capture system 100.

[0022] During combustion operation, the gas turbine system 12 may be outputting exhaust gas 62, and the gas capture system 20 (e.g., carbon capture system 100) may be performing adsorption operations to enable gas capture of undesirable 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 supply 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 leads 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 the remaining steam / water to a condensate line 88 coupled to the LP steam section 74 of the HRSG 16. The condensate line 88 may include a condenser 90 configured to condense the remaining steam to form a condensate, and a pump 92 configured to pump the condensate back to the LP steam section 74. In certain embodiments, the steam turbine system 14 may supply heated water and / or steam to the carbon capture system 100 to support the desorption mode (e.g., regeneration operation) of the carbon capture system 100. The following description focuses on the carbon capture system 100, but the illustrated embodiments are applicable to any type of gas capture system 20. As illustrated, for example, the LP steam turbine 86 may supply steam to the carbon capture system 100 via the main extraction line 152.

[0023] To facilitate the movement of steam between the HRSG16, the steam turbine system 14, and the carbon capture system 100, the controller 22 may adjust the position of one or more valves (e.g., actuator-driven valves) in the combined cycle system 10. For example, the controller 22 may instruct a first valve set 154 located between the HRSG16 and the steam turbine system 14 to open to supply HP steam 76, IP steam 78, and / or LP steam 80 to the steam turbine system 14. In another example, the controller 22 may instruct a second valve set 156 to open to supply LP steam 80 to the carbon capture system 100. When the controller 22 instructs the second valve set 156 to open to supply LP steam 80 to the main extraction line 152, it may instruct the first valve set 154 to close. In yet another example, the controller 22 may instruct a third valve 158 coupled to the LP steam turbine 86 to adjust its position based on the direction of the steam. For example, the controller 22 may instruct a third valve 158 to open in a first direction to supply steam from the LP steam 80 or IP steam turbine 84 to the LP steam turbine 86, and to open in a second direction to supply steam from the LP steam turbine 86 to the carbon capture system 100 via the main extraction line 152.

[0024] After a certain period of time, the controller 22 may initiate a controlled shutdown of the combined cycle system 10. The controlled shutdown may initiate load reduction of the gas turbine system 12 from a first load condition (e.g., a higher load condition or a full load condition) to a second load condition (e.g., a lower load condition or a partial load condition), and may initiate shutdown of steam flow through steam turbines (e.g., HP steam turbine 82, IP steam turbine 84, and LP steam turbine 86) by closing the main valve and opening the bypass valve. For example, the controller 22 may isolate the steam turbine system 14 from the HRSG 16 to shut down the steam turbine system 14 by instructing closing of the first valve set 154, the second valve set 156, and the third valve 158. When the valves reach a minimum position (e.g., a closed position), the steam turbine system 14 may be tripped and begin to decelerate. In other examples, the controller 22 may instruct the steam turbine system 14 to decelerate based on an instruction to the valves to close.

[0025] During a controlled shutdown of the combined cycle system 10, the controller 22 may instruct the gas turbine system 12 to operate for an extended period at a reduced load (e.g., partial load), thereby generating steam 128 in the HRSG 16 for the regeneration operation of the carbon capture system 100. In other words, instead of immediately continuing the shutdown of 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 a full load state (e.g., 100% power output) to a partial load state (e.g., 30% or less, 40% or less, 50% or less, or 60% or less power output) in order to continue supplying exhaust gas 62 to the HRSG 16 to generate steam 128. For example, during regeneration, the controller 22 may instruct the gas turbine system 12 to maintain a partial load state at a constant load and / or a gradually decreasing load, while still allowing the HRSG 16 to generate enough steam 128 for regeneration. In yet another example, the controller 22 may instruct the gas turbine system 12 to maintain a minimum environmental load (MECL) to allow the HRSG 16 to generate steam 128. The steam 128 may be residual steam generated while the gas turbine system 12 was operating at a partial load state.

[0026] During shutdown, steam generated by the HRSG16 can be supplied to the carbon capture system 100 via a backup line 160. For example, the backup line 160 may be located between the HRSG16 and the steam turbine system 14. As shown in the figure, the inlet of the backup line 160 may be located between the HRSG16 and the HP steam turbine 82, and the outlet of the backup line 160 may be located along the main extraction line 152. The backup line 160 may include another inlet located between the HRSG16 and the IP steam turbine 84. To supply steam 128, the controller 22 may instruct a fourth set of valves 161 on the backup line 160 to open. Thus, the steam 128 output by the HRSG16 (e.g., HP steam 76, IP steam 78) can be captured by the backup line 160 and supplied to the carbon capture system 100.

[0027] Steam 128 may include high-temperature reheat steam and low-temperature reheat steam. High-temperature reheat steam may include steam 128 that traverses the backup line 160 from the outlet of the IP steam turbine 84 to the carbon capture system 100. Low-temperature reheat steam may include steam supplied from the outlet of the HP return steam 150 along an additional backup line 167 to the backup line 160 and the carbon capture system 100. The temperature of the high-temperature reheat steam may be higher than that of the low-temperature reheat steam.

[0028] The backup line 160 may include a fifth valve 162 that 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 a shutdown operation to supply steam along the backup line 160 and to close during a combustion operation.

[0029] The backup line 160 may also include a first desuperheater 164 configured to desuperheat or control the temperature of the steam 128. For example, 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 the temperature range, the first desuperheater 164 along the backup line 160 receives water from a desuperheating water source 166 to adjust the temperature of the steam 128. For example, the desuperheating water source 166 may adjust the temperature of the steam 128 based on a temperature control setpoint which may be determined based on the regeneration process. The desuperheating water source 166 may inject water into the desuperheater 164 along the backup line 160 to lower the temperature of the steam 128 if the temperature of the steam 128 is higher than the temperature control setpoint.

[0030] The controller 22 may control the operation of the desuperheating water source 166 based on a temperature range. For example, the controller 22 may monitor the temperature of steam 128 via one or more temperature sensors and instruct a sixth set of valves 168 to open or close based on a comparison of that temperature with a first temperature range. If the temperature of steam 128 is outside the first temperature range, the controller 22 may instruct the sixth set of valves 168 to open to supply water from the desuperheating water source 166 to the first desuperheater 164 to adjust the temperature of steam 128. If the temperature of steam 128 is within the first temperature range, the controller 22 may instruct the sixth set of valves 168 to close or remain closed. If the steam 128 exceeds an upper safety threshold (e.g., maximum steam pressure and / or maximum steam temperature), the controller 22 may instruct a safety valve 170 along the backup line 160 to open for safety reasons and release the steam pressure. The safety valve 170 may include a pressure relief valve.

[0031] The main extraction line 152 may include a second desuperheater 174 configured to desuperheat 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 200–300 degrees Celsius. The 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 valve set 172 to open to inject water into the second desuperheater 174 along the main extraction line 152 to adjust the temperature of steam 128. If the temperature of steam 128 is within the second temperature range, the controller 22 may instruct the seventh valve set to close or remain closed. From the main extraction line 152, steam 128 may be supplied to the carbon capture system 100 for regeneration operation.

[0032] The carbon capture system 100 may perform a regeneration operation using steam 128. The regeneration operation may involve desorbing undesirable gases from the separation material (e.g., adsorbent material in an adsorber, solvent in a stripper) by heating the separation material. 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 in order to remove undesirable gases from the adsorbent material. In another example, the carbon capture system 100 may heat a CO2-rich solvent to strip undesirable gases from the solvent and provide a CO2-dilute solvent. The HRSG 16 may supply steam 128 to the carbon capture system 100 for any appropriate period during a shutdown operation, for example, while the gas turbine system 12 is operating at partial load and the steam turbine system 14 remains shut down. The controller 22 may monitor the regeneration operation for completion. For example, the controller 22 may monitor the concentration of undesirable gases in the separation material, the amount of time spent performing the regeneration operation, etc. In response to deciding to complete the regeneration operation, the controller 22 may continue the shutdown operation until it is complete. For example, the controller 22 may instruct the fourth valve set 161, the fifth valve 162, or both, to close in order to stop the supply of steam 128 to the carbon capture system 100. In another example, the controller 22 may instruct the gas turbine system 12 to continue load reduction and eventually shut down completely. Thus, the controller 22 may complete the shutdown of the combined cycle system 10. By supplying steam 128 during the shutdown operation, the regeneration of the separated material may be completed, allowing the subsequent start operation to begin the carbon capture operation more quickly and efficiently. Thus, the carbon capture rate of the combined cycle system 10 may increase during the subsequent start operation.

[0033] As described herein, the valves may include any suitable valves for supplying heated water and / or steam between the steam turbine system 14 and the HRSG 16 and the carbon capture system 100. For example, the valves may include check valves, bidirectional valves, ball valves, gate valves, butterfly valves, and the like. Each valve may be coupled to an actuator (e.g., an electric actuator, a pneumatic actuator, and / or a hydraulic actuator) that controls the position of the valve. For example, the actuator may adjust the position of the valve between an open position and a closed position based on instructions from the controller 22.

[0034] Figure 3 is a flowchart of one embodiment of a process 200 for shutting down the combined cycle system 10 of Figures 1 and 2. In the illustrated embodiment, the process 200 can be partially or entirely controlled by the controller 22 of Figures 1 and 2. The process 200 includes initiating a controlled shutdown of the plant 10, which has a gas turbine system 12, a steam turbine system 14, a heat recovery steam generator (HRSG) 16, and a carbon capture system 100 (block 202). The process 200 also controls valves during the controlled shutdown to direct steam from the HRSG 16 to the carbon capture system 100 for regeneration (block 204). For example, the controller 22 may instruct a first valve set 154, a second valve set 156, and a third valve 158 to close the steam turbine system 14 to isolate it from the HRSG 16. The controller 22 may also instruct the fourth valve set 161 and the fifth valve 162 to open to supply steam 128 to the carbon capture system 100. The process 200 then completes the controlled shutdown of the plant 10 after the regeneration of the carbon capture system 100 is complete (block 206). For example, the controller 22 may instruct the fourth valve set 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 load reduction and completely shut down, or both. Thus, the controller 22 may complete the controlled shutdown of the combined cycle system 10 after the complete regeneration of the separated material in the carbon capture system 100.

[0035] Figure 4 is a flowchart of one embodiment of process 240 for shutting down the combined cycle system 10 of Figures 1 and 2. In the illustrated embodiment, process 240 can be partially or entirely controlled by the controller 22 of Figures 1 and 2. Process 240 includes initiating a controlled shutdown of the plant 10 having a gas turbine system 12, a steam turbine system 14, a heat recovery steam generator (HRSG) 16, and a carbon capture system 100 (block 242). Process 240 also controls the gas turbine system 12 to reduce it to a partial load state (block 244). In certain examples, the gas turbine system 12 may be operating at full load. In other examples, the gas turbine system 12 may be operating at a partial load state lower than full load, such as 30%, 40%, 50%, or 60% of full load. Process 240 then controls the valves of the steam turbine system 14 to close in order to initiate the shutdown of the steam turbine system 14 (block 246). For example, the controller 22 may instruct the first set of valves 154 to close the steam turbine system 14 to isolate it from the HRSG 16. Process 240 may also shut down the steam turbine system 14 after the valves have been closed (block 248). Process 240 may control the valves to direct steam from the HRSG 16 to supply steam to the carbon capture system 100 (block 250). For example, the controller 22 may instruct the valves to open to direct steam 128 from the HRSG 16 to the carbon capture system 100 via the backup line 160. Process 240 may also control the carbon capture system 100 to regenerate using the steam 128 from the HRSG 16 (block 252). For example, the controller 22 may instruct the carbon capture system 100 to operate in desorption mode using the steam 128 (e.g., perform a regeneration operation). Process 240 may monitor the carbon capture system 100 for the completion of regeneration (block 254). For example, the controller 22 may decide to complete the process based on the passage of a certain period of time, the concentration of an undesirable gas in the separation material, or both.Next, process 240 may control a valve to stop (e.g., close) the steam 128 from HRSG16 to the carbon capture system 100 when regeneration is complete (block 256). For example, controller 22 may instruct the valve to close in order to stop the steam from HRSG16 from being directed to the carbon capture system 100. Process 240 may also control the gas turbine system 12 to continue load reduction to complete the controlled shutdown of the plant (block 258).

[0036] The technical effect of the disclosed embodiments is to improve gas capture by adsorbent-based gas capture (e.g., carbon capture of CO2) systems or solvent-based gas capture systems by supplying steam during the shutdown process. During the shutdown process, for example, a gas turbine may operate at load (e.g., partial load) and output exhaust gas, thereby allowing the HRSG to continue outputting steam. Steam may be supplied to the gas capture system via a backup line for a regeneration process. For example, steam may strip unwanted gases (e.g., CO2) from a CO2-rich solvent, increasing the total CO2 captured in the gas capture system before a complete shutdown. In another example, steam may desorb unwanted gases (e.g., CO2) from an adsorbent material, thereby regenerating the adsorbent material. By supplying steam to the gas capture system, the amount of dilute CO2 solvent and / or dilute CO2 adsorbent material for carbon capture during subsequent startup operations may be increased. Thus, the disclosed embodiments may provide an increased CO2 capture rate during the next startup process by increasing the amount of dilute solvent and / or available adsorbent material.

[0037] The subject matter described in detail above may be defined by one or more of the following clauses.

[0038] A gas capture system including a separation material, wherein the gas capture system is configured to operate a regeneration process during partial load operation and / or shutdown operation to desorb undesirable gases from the separation material and lean the separation material for an absorption process; a heat recovery steam generator (HRSG) configured to receive exhaust gas and generate steam; and a backup line fluidly coupling 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.

[0039] A system as described in or related to the preceding clause and / or any appended claim, comprising a main extraction line, which is fluidly coupled to or branches off from a heat recovery steam generator and configured to supply steam from the heat recovery steam generator to a gas capture system, and a backup line, which is also fluidly coupled to or branches off from the heat recovery steam generator at at least one steam extraction location, and which provides a higher steam pressure than the steam extraction locations where the main extraction line is coupled to or branches off 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, and the backup line may branch off 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.

[0040] A system described in or relating to any preceding clause and / or any appendix, including a gas turbine system configured to output exhaust gases during partial load operation and / or shutdown operation.

[0041] A system as described in or related to any preceding clause and / or any appendix, comprising: a desuperheater coupled to a backup line, the desuperheater configured to control the temperature of steam along the backup line; a pressure reducing valve for controlling the pressure of steam for a regeneration process; and a safety valve coupled to a backup line, the safety valve configured to release steam when the steam pressure exceeds a pressure threshold.

[0042] A system as described in or related to any preceding clause and / or any appendix claim, including a desuperheating water source configured to inject water into a desuperheater along a backup line based on the steam temperature being higher than a temperature control setpoint for the regeneration process.

[0043] A system described in or relating to any preceding clause and / or any appendix, wherein the backup line is configured to supply vapor to the main extraction line, which is fluid-coupled to the gas capture system.

[0044] A system as described in or related to any preceding clause and / or any appendix, wherein the main extraction line comprises a desuperheater configured to control the temperature of the steam along the main extraction line.

[0045] A system as described in or related to any preceding clause and / or any appended claim, including a desuperheating water source configured to inject water into a desuperheater along the main extraction line based on the steam temperature being higher than a temperature control setpoint for the regeneration process.

[0046] A system as described in or related to any preceding clause and / or any appendix, comprising a steam turbine fluidly coupled to an HRSG via a valve set, and a controller communicably coupled to the valve set, wherein the controller is configured to control each valve of the valve set to at least partially close based on receiving instructions to initiate partial load operation and / or shutdown operation.

[0047] A system as described in or related to any preceding clause and / or any appendix, wherein the controller is configured to monitor the regeneration process of the gas capture system and the steam from the HRSG, and to initiate the supply of steam from an additional steam source to support the regeneration process of the gas capture system based on the amount of steam from the HRSG being less than a threshold steam supply.

[0048] A system described in or related to any preceding clause and / or any appended claim, wherein an additional steam supply source comprises an auxiliary boiler.

[0049] The system may include a plant comprising a gas turbine configured to output exhaust gases, a heat recovery steam generator (HRSG) configured to receive exhaust gases and output steam, and a steam turbine configured to receive steam. The system may also include a carbon capture system configured to capture undesirable gases from the exhaust gases in the separation material, and a controller configured to initiate partial load operation and / or shutdown operation of the plant. The controller may control the gas turbine to reduce to a partial load state and continue outputting exhaust gases, control a first set of valves to at least partially close to reduce or disable the flow of steam to the steam turbine, and control a second set of valves to allow or increase the flow of steam from the HRSG to the carbon capture system via a backup line to perform a regeneration process on the separation material. More specifically, the system may include a main extraction line fluidly coupled to or branching off from the heat recovery steam generator and configured to supply steam from the heat recovery steam generator to the gas capture system. The backup lines are also fluidly coupled to or branch off from the heat recovery steam generator at at least one steam extraction location, providing a higher steam pressure than the steam extraction locations where the main extraction lines are coupled to or branch off from the heat recovery steam generator. For example, the main extraction lines may branch off from lines configured to supply steam to a low-pressure steam turbine or a low-pressure steam turbine section, and the backup lines may branch off from lines 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 lines 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 lines 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.

[0050] A system described in or relating to any preceding clause and / or any appendix, configured such that a controller controls the carbon capture system to perform a regeneration process using steam from the HRSG.

[0051] A system as described in or related to any preceding clause and / or any appendix, wherein the controller is configured to control a second set of valves to close in order to stop steam from the HRSG to the carbon capture system based on the completion of the regeneration process or on a change from the HRSG to an additional steam supply source for the completion of the regeneration process.

[0052] A system as described in or related to any preceding clause and / or any appendix, wherein the controller is configured to control an additional steam source to initiate a steam supply 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.

[0053] A system as described in or related to any preceding clause and / or any appended claim, including a desuperheating water source configured to inject water into a desuperheater along a backup line based on the fact that the temperature of the steam along the backup line is higher than a temperature control setpoint for the regeneration process.

[0054] A system as described in or related to any preceding clause and / or any appendix, wherein the controller is configured to control a second set of valves so that steam from the high-pressure (HP) steam section of the HRSG, the medium-pressure (IP) steam section of the HRSG, or a combination thereof, is directed to the carbon capture system during the regeneration process.

[0055] A system as described in or related to any preceding clause and / or any appended claim, wherein the separation material comprises an adsorbent material or a solvent.

[0056] The method may include initiating a shutdown or partial load operation of a plant having a gas turbine, a steam turbine, a heat recovery steam generator (HRSG), and a carbon capture system having separation material; controlling the gas turbine to reduce to a partial load state; controlling a first set of valves to at least partially close in order to reduce or disable the flow of steam to the steam turbine; and controlling a second set of valves coupled to a backup line to allow or increase the flow of steam from the HRSG to the carbon capture system in order to carry out a regeneration process on the separation material.

[0057] A method described in or relating to any preceding clause and / or any appendix claim, further comprising monitoring a carbon capture system during a regeneration process, controlling a second set of valves to stop directing steam to the carbon capture system based on detection that the carbon capture system has completed a regeneration process, and controlling a gas turbine to continue load reduction to complete a plant shutdown operation.

[0058] A method described in or related to any preceding clause and / or any appendix claim, further comprising controlling the steam supply from an additional steam supply source to support the regeneration process of a carbon capture system, based on the steam supply from the HRSG being less than the threshold steam supply.

[0059] This specification uses examples to disclose the present invention in best mode and to enable any person skilled in the art to carry out the invention, including the fabrication and use of any device or system, and the execution of any method incorporating it. The scope of the invention as claimed herein is defined by the appended claims and may include other examples beyond those provided in the above description that a person skilled in the art might conceive. [Explanation of Symbols]

[0060] 10 Combined cycle systems, combined cycle plants, plants 12. Gas turbine systems, systems, gas turbines 14. Steam turbine systems, systems, steam turbines 16. Heat Recovery Steam Generator, HRSG, System 18 Gas Processing System 20 Gas Capture Systems 22 controllers 36 Rotation axis 40 Axial direction or axis 42 Radial or axial 44 Circumferential direction or axis 50 Intake port 52 Compressor 54 Combustor 56 Turbine 58 load 60 Exhaust gas recirculation (EGR) system, EGR system 62 Exhaust gas 70 HP steam section, high-pressure steam section 72 IP steam section, medium-pressure steam section 74 LP steam section 76. High-pressure (HP) steam, HP steam 78. Medium-pressure (IP) steam, IP steam 80 Low-pressure (LP) steam, LP steam 82 HP steam turbine 84 IP Steam Turbine 86 LP Steam Turbine 88 Condensate Line 90 Condenser 92 pumps 94 load 100 Carbon Capture Systems 102 Components 104 Components 106 Components 108 components 110 Processed gas 112 Captured gas 114 Compression System 116 Storage and / or pipeline systems 120 processors 122 memory 124 Instructions 126 Communication Circuit 128 Steam 130 valve set 150 HP Return Steam 152 Main extraction line 154 First valve set 156 Second valve set 157 Auxiliary boiler 158 The Third Defense 160 backup lines 161 Fourth valve set 162. Fifth valve, pressure reducing valve 164 First desuperheater, desuperheater 166 Detemperature water source 167 Additional backup lines 168 Valve set No. 6 170 Safety valve 172 Valve set No. 7 174 Second desuperheater, desuperheater 200 processes 240 processes

Claims

1. A gas capture system (20) including a separation material, wherein the gas capture system (20) is configured to capture undesirable gases from exhaust gas (62) in the separation material and to operate a regeneration process to desorb the undesirable gases from the separation material and regenerate the separation material for an absorption process, A heat recovery steam generator (16) is configured to receive the exhaust gas (62) and generate steam (128), A backup line (160) fluidly connects the gas capture system (20) to the heat recovery steam generator (16), wherein the backup line (160) is configured to supply steam (128) from the heat recovery steam generator (16) to the gas capture system (20) for the regeneration process during partial load operation and / or shutdown operation. A system equipped with these features.

2. The system according to claim 1, wherein the backup line (160) is fluidly coupled to the high-pressure steam section (70) of the heat recovery steam generator (16), the medium-pressure steam section (72) of the heat recovery steam generator (16), or a combination thereof, and is configured to supply steam (128) from the heat recovery steam generator (16) to the gas capture system (20) for the regeneration process from the high-pressure steam section (70) of the heat recovery steam generator (16), the medium-pressure steam section (72) of the heat recovery steam generator (16), or a combination thereof.

3. A desuperheater (164) connected to the backup line (160), wherein the desuperheater (164) is configured to control the temperature of the steam (128) flowing along the backup line (160), A pressure reducing valve (162) for controlling the pressure of the steam (128) supplied from the backup line (160) to the gas capture system (20), A safety valve (170) coupled to the backup line (160), wherein the safety valve (170) is configured to release steam when the steam pressure of the steam (128) supplied from the backup line (160) to the gas capture system (20) exceeds a pressure threshold, and The system according to claim 1, comprising:

4. The system according to claim 1, wherein the backup line (160) is configured to supply the steam (128) to the main extraction line (152) which is fluidly coupled to the gas capture system (20).

5. The system according to claim 4, wherein the main extraction line (152) is equipped with a desuperheater (174) configured to control the temperature of the steam (128) flowing along the main extraction line (152).

6. A gas turbine (12) configured to output the exhaust gas (62), A steam turbine (14) is fluidly coupled to the heat recovery steam generator (16) and configured to receive steam (128) from the heat recovery steam generator (16), The partial load operation and / or shutdown operation of a plant comprising the gas turbine (12), the steam turbine (14), the heat recovery steam generator (16), and the gas capture system (20) Controlling the gas turbine (12) to reduce the load to a partial load state and to continue outputting the exhaust gas (62) (244), To perform a regeneration process on the separated material, at least one of the following is to enable or increase the flow of steam from the heat recovery steam generator (16) to the gas capture system (20) via the backup line (160) for a certain period of time. A controller (22) configured to be started by and The system according to claim 1, further comprising:

7. The system according to claim 6, wherein the controller (22) is configured to reduce or disable the flow of steam from the heat recovery steam generator (16) to the steam turbine (14).

8. The system according to claim 6, wherein the controller (22) is configured to control a first set of valves (154) to be at least partially closed in order to achieve a reduction or neutralization of the flow of steam to the steam turbine (14) (246), and / or to control a second set of valves (156) coupled to the backup line (160) in order to achieve a flow of steam from the heat recovery steam generator (16) to the gas capture system (20) via the backup line (160) (250).

9. The controller (22) Controlling the gas capture system (20) to perform the regeneration process using steam (128) from the heat recovery steam generator (16) (252), Monitoring the regeneration process of the gas capture system (20) over the aforementioned period (254), Based on the completion of the regeneration process, or based on the change from the heat recovery steam generator (16) to an additional steam supply source for the completion of the regeneration process, the flow of steam from the heat recovery steam generator (16) to the gas capture system (20) is stopped (256) The system according to claim 6, configured to perform the following:

10. (242) Initiating a shutdown operation or partial load operation of a plant having a gas turbine (12), a steam turbine (14), a heat recovery steam generator (16), and a gas capture system (20) having separation material, Controlling the gas turbine (12) to reduce the load to a partial load state (244), To perform a regeneration process on the separated material, enable or increase the flow of steam from the heat recovery steam generator (16) to the gas capture system (20) via the backup line (160). Methods that include...

11. The method according to claim 10, comprising reducing or disabling the flow of steam from the heat recovery steam generator (16) to the steam turbine (14).

12. The method according to claim 10, comprising controlling a first set of valves (154) to be at least partially closed (246) in order to achieve a reduction or neutralization of the steam flow to the steam turbine (14), and / or controlling a second set of valves (156) coupled to the backup line (160) (250) in order to achieve a flow of steam from the heat recovery steam generator (16) to the gas capture system (20) via the backup line (160).

13. Monitoring the gas capture system (20) during the regeneration process (254), Based on the detection that the gas capture system (20) has completed the regeneration process, the supply of steam (128) to the gas capture system (20) is stopped (256), Controlling the gas turbine (12) to continue reducing the load in order to complete the shutdown operation of the plant (258) It further includes, The method according to claim 10, wherein stopping the introduction of steam (128) into the gas capture system (20) includes controlling a second valve set.

14. The method according to claim 10, further comprising controlling the steam supply from an additional steam supply source to support the regeneration process of the gas capture system (20) based on the steam supply from the heat recovery steam generator (16) being less than a threshold steam supply.

15. The system according to claim 1, further comprising a controller (22) configured to perform the method described in claim 10.

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