A wet air turbine cycle combined heat and power system

Abstract

The present invention discloses a wet air turbine cycle cogeneration system, wherein a bypass exhaust pipeline is arranged between the compressor exhaust port and the combustion chamber, so that a part of the compressed air at the compressor exhaust port can directly enter the combustion chamber without passing through an aftercooler, a humidifier and a regenerator, and regulating valves are respectively arranged on the bypass exhaust pipeline and the main exhaust pipeline to control the flow of the compressed air, thereby realizing flexible control of the heat-electricity ratio of the cogeneration system, and a check valve is arranged at the compressor exhaust port, a check valve is arranged at the inlet of the aftercooler, and a quick shut-off valve is arranged on the cold side outlet air pipeline of the regenerator, so that the safety of the gas turbine under load rejection working conditions can be effectively guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of new thermal cycles of gas turbines, and relates to an air turbine cycle cogeneration system, and specifically to a humid air turbine cycle (HAT) cogeneration system, which can flexibly adjust the heat-electricity ratio of the cogeneration system and effectively ensure the safety of the gas turbine under load rejection conditions. Background Art

[0002] The wet air turbine cycle achieves air humidification through direct countercurrent contact between hot water and compressed air, thereby utilizing the low-temperature heat of the flue gas. At the same time, the high-temperature heat of the turbine exhaust gas is recovered through the regenerator and then enters the combustion chamber. After combustion and heating, it enters the turbine to expand and do work. Finally, the waste heat of the flue gas exhausted from the turbine is absorbed by the low-temperature fluid in the regenerator, evaporator, and economizer, and the turbine flue gas is discharged into the atmosphere. This cycle has the advantages of high efficiency, high specific power, low pollution, lower cost potential, and good variable operating performance. It is one of the important directions for the development of new gas turbine thermal cycles.

[0003] In the HAT cycle, the high-temperature flue gas discharged from the gas turbine is partially preheated by the regenerator to preheat the compressed air, thereby increasing the air temperature entering the combustion chamber and reducing fuel consumption, thereby improving the cycle efficiency. After the turbine exhaust gas is cooled by the regenerator, it enters the evaporator to generate steam, and the flue gas is further cooled, and then enters the economizer to generate hot water. Finally, the cooled flue gas is discharged from the chimney.

[0004] Under pure power generation conditions, the steam and hot water generated by flue gas cooling are used to humidify the compressed air at the outlet of the gas turbine compressor. When the wet air turbine cycle is required to supply hot water or steam to the outside, the waste heat of the gas turbine exhaust needs to be supplied to the outside. The hot water from the economizer can be mixed with the hot water from the aftercooler, and part of it can be diverted to supply hot water to the outside, and the other part can enter the humidifier to heat the wet air, or steam can be supplied to the outside through the evaporator. When the heat load demand of external users changes, it is necessary not only to reasonably control the heat and power ratio of the cogeneration system, but also to try to ensure that the heat of the system is reasonably utilized in a step-by-step manner, which requires the system to have flexible heat and power ratio adjustment performance. In addition, the safety of the system must be considered when the system is in a load shedding condition. Summary of the invention

[0005] (I) Purpose of the invention

[0006] In order to solve the above technical problems, the present invention proposes a wet air turbine cycle cogeneration system, in which a bypass exhaust pipeline is arranged between the compressor exhaust port and the combustion chamber, so that a part of the compressed air at the compressor exhaust port can directly enter the combustion chamber without passing through an aftercooler, a humidifier and a regenerator, and regulating valves are respectively arranged on the bypass and the main line to control the flow rate of the compressed air, thereby realizing flexible control of the heat and power ratio of the cogeneration system, and a check valve is arranged at the compressor exhaust port, a check valve is arranged at the inlet of the aftercooler, and a quick shut-off valve is arranged on the cold side outlet air line of the regenerator, so that the safety of the gas turbine under load rejection conditions can be effectively guaranteed.

[0007] (II) Technical solution

[0008] A wet air turbine cycle cogeneration system comprises at least a compressor, a combustion chamber, an aftercooler, a humidifier, a regenerator, a combustion chamber turbine, a power turbine, an economizer, a chimney and a generator, wherein the combustion chamber turbine is drivingly connected to the compressor, and the power turbine is drivingly connected to the generator, and is characterized in that:

[0009] The air inlet of the compressor is connected to the atmosphere, and the exhaust port is provided with a main exhaust pipeline and a bypass exhaust pipeline. The exhaust port of the compressor is connected to the air inlet of the combustion chamber through the main exhaust pipeline in sequence through the aftercooler, the humidifier, and the cold side of the regenerator. The exhaust port of the compressor is also directly connected to the air inlet of the combustion chamber through the bypass exhaust pipeline; the high-temperature fuel gas outlet of the combustion chamber is connected to the chimney through a pipeline in sequence through the combustion chamber turbine, the power turbine, the hot side of the regenerator, and the hot side of the economizer;

[0010] The drainage pipeline of the humidifier is divided into two routes, one of which is connected to the water inlet of the humidifier after passing through the aftercooler, and the other is connected to the water inlet of the humidifier after passing through the cold side of the economizer. The cold side of the economizer is also connected to the external heating component through a pipeline to supply hot water or hot steam to the user side;

[0011] At least one first regulating valve is arranged on the bypass exhaust pipeline, and the first regulating valve is used for regulating the air flow of the compressor directly entering the combustion chamber from the bypass exhaust pipeline; at least one second regulating valve is arranged on the main exhaust pipeline and is located in front of the air inlet of the aftercooler, and the second regulating valve is used for regulating the air flow of the compressor from the main exhaust pipeline through the aftercooler, the humidifier, and the regenerator and then entering the combustion chamber; at least one third regulating valve is arranged on the connecting pipeline between the cold side of the economizer and the external hot water supply / hot steam component, and / or the connecting pipeline between the economizer and the humidifier, and the third regulating valve is used for regulating the hot water flow of the cold side of the economizer flowing through the external hot water supply / hot steam component and / or the humidifier.

[0012] In a preferred example of the present invention, at least one first check valve is provided at the exhaust port of the compressor, the inlet of the first check valve is connected to the exhaust port of the compressor, and the outlet is connected to the main exhaust pipeline and the bypass exhaust pipeline, at least one second check valve is provided on the main exhaust pipeline and is located in front of the air inlet of the aftercooler, and at least one quick shut-off valve is provided on the cold side outlet air pipeline of the regenerator. When the system experiences a load shedding condition, the first check valve is used to prevent the compressed air from flowing back to the compressor and causing surge, the second check valve is used to prevent the compressed air from entering the combustion chamber, and the quick shut-off valve is used to prevent the compressed air from entering the combustion chamber and causing overspeed expansion of the combustion chamber turbine and the power turbine.

[0013] In a preferred embodiment of the present invention, at least one drain valve is provided on the humidifier, and the drain valve is used to drain water when the system is in a non-working state or an emergency state to avoid accidents.

[0014] In a preferred embodiment of the present invention, the exhaust port of the chimney is connected to the atmosphere.

[0015] In a preferred example of the present invention, the system adjusts the air ratio of the exhaust gas of the compressor distributed to the regenerator and the combustion chamber through the first regulating valve and the second regulating valve, and adjusts the hot water flow rate distributed from the cold side of the economizer to the external heating component and the humidifier through the third regulating valve.

[0016] In a further preferred example of the present invention, when there is no heat load demand on the user side, the connecting pipe between the cold side of the economizer and the external heating component is closed by the third regulating valve, and the external heating ratio is 0 at this time; when there is a heat load demand on the user side, the opening of the third regulating valve is gradually adjusted to gradually increase the ratio of the external heating component until the external heating ratio is 1, that is, all hot water is supplied to the outside and the supply of hot water to the humidifier is stopped.

[0017] In a further preferred example of the present invention, when the heat load demand on the user side further increases, the opening of the first regulating valve is increased and the opening of the second regulating valve is reduced to reduce the proportion of the compressor's exhaust gas allocated to the aftercooler and the humidifier, thereby further increasing the external heating amount.

[0018] The wet air turbine cycle cogeneration system of the present invention flexibly adjusts the external heat supply by adjusting the proportion of external heat supply and the proportion of air entering the regenerator. When the HAT cycle is purely generating electricity, the proportion of external heat supply is 0; when the user has a heat load demand, the proportion of external heat supply is gradually increased until the proportion of external heat supply is 1, that is, all hot water is supplied to the outside for heat; when the user needs external steam supply, the water in the economizer is supplied to the outside through the evaporator for steam supply, and when the user needs a further increase in heat load, the external heat supply can be increased by reducing the proportion of compressor outlet air entering the aftercooler and humidifier.

[0019] The above system realizes a wide range of heat-to-electricity ratio regulation, but the system may have two problems when the gas turbine, especially the gas turbine with power turbine, is unloaded: one is the turbine overspeed under load shedding conditions, especially the gas turbine with power turbine; the other is the surge of the compressor. It poses a huge threat to the safe operation of the unit. The reason for the above problems is that the air side volume of the aftercooler, humidifier, and regenerator is large, and a large amount of compressed air is stored in this volume. Under the condition of gas turbine load shedding, although the fuel of the gas turbine has been cut off, this part of compressed air may still enter the power turbine. Under the condition of load shedding, the power turbine has no load, which may cause overspeed. At the same time, because the turbine of the core engine of the gas turbine cannot maintain the compressor working condition, the compressor will surge.

[0020] The wet air turbine cycle cogeneration system of the present invention further proposes a method for ensuring the safety of the gas turbine under load shedding in view of the characteristics of the system. A check valve is set at the compressor outlet, a check valve is set at the aftercooler inlet, and a quick shut-off valve is set on the air pipeline at the cold side outlet of the regenerator. When the system encounters a load shedding condition, the compressor outlet check valve prevents the compressed air from flowing back to the compressor and causing surge, the aftercooler inlet check valve prevents the compressed air from entering the combustion chamber through the bypass, and the shut-off valve on the regenerator outlet air pipeline is quickly shut off to prevent the compressed air from entering the combustion chamber and the turbine and causing the power turbine to overspeed, thereby ensuring the safety of the gas turbine under load shedding conditions.

[0021] In a preferred example of the present invention, when the system encounters a load shedding condition, the first check valve is used to prevent compressed air from flowing back into the compressor and causing surge, and the second check valve is used to prevent compressed air from entering the combustion chamber. The air intake line of the combustion chamber is quickly shut off by the quick shut-off valve to prevent compressed air from entering the combustion chamber and causing overspeed expansion of the combustion chamber turbine and the power turbine, thereby ensuring the safety of the system under load shedding conditions.

[0022] (III) Technical Effect

[0023] Compared with the prior art, the wet air turbine cycle cogeneration system of the present invention has the following beneficial effects:

[0024] (1) The wet air turbine cycle cogeneration system of the present invention adds a bypass exhaust pipeline between the compressor outlet and the combustion chamber, so that a portion of the compressed air discharged from the compressor can directly enter the combustion chamber.

[0025] (2) The wet air turbine cycle cogeneration system of the present invention provides regulating valves on the bypass between the compressor outlet and the combustion chamber and on the main road before the aftercooler inlet, respectively, for regulating the air flow directly entering the combustion chamber from the bypass and the air flow flowing from the main road through the aftercooler, the humidifier and the regenerator and then entering the combustion chamber, thereby maximizing the heat-to-electricity ratio regulation capability of the cogeneration system.

[0026] (3) The wet air turbine cycle cogeneration system of the present invention, by arranging a check valve at the compressor outlet, a check valve at the aftercooler inlet, and a quick shut-off valve on the cold side outlet air pipeline of the regenerator located before the combustion chamber air inlet, can prevent the compressed air from flowing back to the compressor and causing the compressor to surge, and prevent the compressed air from entering the combustion chamber and the turbine and causing the turbine to overspeed when the system experiences a load shedding condition, thereby improving the safety performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the wet air turbine cycle cogeneration system of the present invention.

[0028] Figure 2 It is a schematic diagram of air circulation in the present invention.

[0029] Figure 3 Schematic diagram of water circulation in the present invention.

[0030] Description of reference numerals:

[0031] Compressor 1, combustion chamber 2, bypass exhaust pipeline 3, main exhaust pipeline 4, aftercooler 5, humidifier 6, regenerator 7, combustion chamber turbine 8, power turbine 9, first regulating valve 10, second regulating valve 11, first check valve 12, second check valve 13, quick shut-off valve 14, economizer 15, chimney 16, vent valve 17, generator 18. DETAILED DESCRIPTION

[0032] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, so that the advantages and features of the present invention can be more easily understood by those skilled in the art. It should be noted that the following is only a preferred embodiment of the present invention, but the content of the present invention is not limited to the following embodiments. In fact, various modifications and changes can be made in the present invention without departing from the scope or spirit of the present invention, which will be apparent to those skilled in the art. For example, the features shown or described as a part of an embodiment can be used together with another embodiment to produce another embodiment. Therefore, it is intended that the present invention includes such modifications and changes within the scope of the appended claims and their equivalents.

[0033] For a wet air turbine cycle combined heat and power system, in addition to requiring the system to supply external power, it is also required to supply external hot water. Figures 1 to 3 As shown, the wet air turbine cycle cogeneration system of the present invention comprises at least a compressor 1, a combustion chamber 2, an aftercooler 5, a humidifier 6, a reheater 7, a combustion chamber turbine 8, a power turbine 9, an economizer 15, a chimney 16 and a generator 18. The combustion chamber turbine 8 is driven and connected to the compressor 1, the power turbine 9 is driven and connected to the generator 18, and the exhaust port of the chimney 16 is connected to the atmosphere. Among them, the air inlet of the compressor 1 is connected to the atmosphere, and the exhaust port is provided with a main exhaust pipeline 4 and a bypass exhaust pipeline 3. The exhaust port of the compressor 1 is connected to the air inlet of the combustion chamber 2 through the main exhaust pipeline 4, through the aftercooler 5, the humidifier 6, and the cold side of the regenerator 7, and the exhaust port of the compressor 1 is also directly connected to the air inlet of the combustion chamber 2 through the bypass exhaust pipeline 3; the high-temperature fuel gas outlet of the combustion chamber 2 is connected to the chimney 16 through the pipeline, through the combustion chamber turbine 8, the power turbine 9, the hot side of the regenerator 7, and the hot side of the economizer 15 in sequence; the drainage pipeline of the humidifier 6 is divided into two routes, one of which is connected to the water inlet of the humidifier 6 after passing through the aftercooler 5, and the other is connected to the water inlet of the humidifier 6 after passing through the cold side of the economizer 15. The cold side of the economizer 15 is also connected to the external heating component through a pipeline (not shown in the figure) for heating the user side.

[0034] At least one first regulating valve 10 is arranged on the bypass exhaust pipeline 3, and the first regulating valve 10 is used to regulate the air flow of the compressor 1 directly entering the combustion chamber 2 from the bypass exhaust pipeline 3; at least one second regulating valve 11 is arranged on the main exhaust pipeline 4 and is located in front of the air inlet of the aftercooler 5, and the second regulating valve 11 is used to regulate the air flow of the compressor 1 from the main exhaust pipeline 4 through the aftercooler 5, the humidifier 6, and the reheater 7 and then enter the combustion chamber 2; at least one third regulating valve is arranged on the connecting pipeline between the cold side of the economizer 15 and the external heating component, and / or the connecting pipeline between the economizer 15 and the humidifier 6, and the third regulating valve is used to regulate the hot water flow of the cold side of the economizer 15 through the external heating component and / or the humidifier 6.

[0035] In a preferred embodiment of the present invention, at least one first check valve 12 is provided at the exhaust port of the compressor 1, the inlet of the first check valve 12 is connected to the exhaust port of the compressor 1, and the outlet is connected to the main exhaust pipeline 4 and the bypass exhaust pipeline 3. At least one second check valve 13 located in front of the air inlet of the aftercooler 5 is provided on the main exhaust pipeline 4, and at least one quick shut-off valve 14 is provided on the cold side outlet air pipeline of the regenerator 7. When the system is in a load rejection condition, the first check valve 12 is used to prevent the compressed air from flowing back to the compressor 1 and surging, the second check valve 13 is used to prevent the compressed air from entering the combustion chamber 2, and the quick shut-off valve 14 is used to prevent the compressed air from entering the combustion chamber 2 and causing the combustion chamber turbine 8 and the power turbine 9 to expand overspeed. At least one vent valve 17 is provided on the humidifier 6, and the vent valve 17 is used to drain water when the system is in a non-working state or an emergency state to avoid accidents.

[0036] When the heat load on the user side needs to change, in order to flexibly adjust the heat-electricity ratio in the wet air turbine cycle heat and power cogeneration system, the present invention adds a bypass exhaust pipeline 3 between the compressor 1 outlet and the combustion chamber 2, so that part of the compressed air can directly enter the combustion chamber 2, and the other part of the compressed air enters the aftercooler 5, the humidifier 6 and the regenerator 7 from the main exhaust pipeline 4 in sequence, and then merges with the compressed air in the bypass exhaust pipeline 3 to enter the combustion chamber 2. The heated air enters the combustion chamber turbine 8 and the power turbine 9 respectively to expand and do work. Part of the work provides power for the compressor 1, and part of the work is generated by the generator 18, and finally discharged into the atmosphere through the chimney 16. The hot water from the humidifier 6 is divided into two paths, one entering the aftercooler 5 and the other entering the economizer 15. The water from the aftercooler 5 and the economizer 15 is mixed and enters the humidifier 6 again. A vent valve 17 is set on the humidifier 6. When it is not working or in an emergency, water can be discharged through the vent valve 17 to avoid accidents. A first regulating valve 10 is provided on the bypass 3 between the exhaust port of the compressor 1 and the air inlet of the combustion chamber 2, for regulating the air flow directly entering the combustion chamber 2 from the bypass 3. Meanwhile, a second regulating valve 11 is provided in front of the inlet of the aftercooler 5 on the main path 4, for regulating the air flow flowing from the main path 4 through the aftercooler 5, the humidifier 6 and the regenerator 7 and then entering the combustion chamber 2, thereby maximizing the heat-to-electricity ratio regulation capability in the cogeneration system.

[0037] In addition, in order to cope with the system load shedding condition, a first check valve 12 is provided at the outlet of the compressor 1, a second check valve 13 is provided at the inlet of the aftercooler 5, and a quick shut-off valve 14 is provided on the cold side outlet air pipeline of the regenerator 7 located in front of the air inlet of the combustion chamber 2. When the system has a load shedding condition, the check valve 12 at the outlet of the compressor 1 can prevent the compressed air from flowing back to the compressor 1 and surging, the check valve 13 at the inlet of the aftercooler 5 prevents the compressed air from entering the combustion chamber 2, and the quick shut-off valve 14 on the outlet pipeline of the regenerator 7 prevents the air from entering the combustion chamber turbine 8 and the power turbine 9 and expanding and causing them to overspeed. The present invention realizes the flexible adjustment of the heat and power ratio in the wet air turbine cycle cogeneration system, and improves the safety of the system when the load shedding condition occurs.

[0038] Through the above embodiments, the purpose of the present invention is fully and effectively achieved. Any equivalent or simple changes made according to the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. The technicians in the technical field of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all belong to the protection scope of the present invention.

Claims

1. A wet air turbine cycle cogeneration system, comprising at least a compressor, a combustion chamber, an aftercooler, a humidifier, a regenerator, a combustion chamber turbine, a power turbine, an economizer, a chimney and a generator, wherein the combustion chamber turbine is drivingly connected to the compressor, and the power turbine is drivingly connected to the generator, characterized in that: The air inlet of the compressor is connected to the atmosphere, and the exhaust port is provided with a main exhaust pipeline and a bypass exhaust pipeline. The exhaust port of the compressor is connected to the air inlet of the combustion chamber through the main exhaust pipeline in sequence through the aftercooler, the humidifier, and the cold side of the regenerator. The exhaust port of the compressor is also directly connected to the air inlet of the combustion chamber through the bypass exhaust pipeline; the high-temperature fuel gas outlet of the combustion chamber is connected to the chimney through a pipeline in sequence through the combustion chamber turbine, the power turbine, the hot side of the regenerator, and the hot side of the economizer; The drainage pipeline of the humidifier is divided into two routes, one of which is connected to the water inlet of the humidifier after passing through the aftercooler, and the other is connected to the water inlet of the humidifier after passing through the cold side of the economizer. The cold side of the economizer is also connected to the external heating component through a pipeline to provide heat to the user side; At least one first regulating valve is provided on the bypass exhaust pipeline, and the first regulating valve is used to regulate the air flow of the compressor directly entering the combustion chamber from the bypass exhaust pipeline; At least one second regulating valve is arranged on the main exhaust pipeline and is located in front of the air inlet of the aftercooler. The second regulating valve is used to regulate the air flow of the compressor from the main exhaust pipeline through the aftercooler, the humidifier, and the regenerator and then into the combustion chamber; at least one third regulating valve is arranged on the connecting pipeline between the cold side of the economizer and the external heating component, and / or the connecting pipeline between the economizer and the humidifier, and the third regulating valve is used to regulate the hot water flow of the cold side of the economizer through the external heating component and / or the humidifier.

2. The wet air turbine cycle cogeneration system according to claim 1, characterized in that: At least one first check valve is also arranged at the exhaust port of the compressor, the inlet of the first check valve is connected to the exhaust port of the compressor, and the outlet is connected to the main exhaust pipeline and the bypass exhaust pipeline. At least one second check valve is arranged on the main exhaust pipeline and is located in front of the air inlet of the aftercooler. At least one quick shut-off valve is arranged on the cold side outlet air pipeline of the regenerator. When the system experiences a load shedding condition, the first check valve is used to prevent the compressed air from flowing back to the compressor and causing surge, the second check valve is used to prevent the compressed air from entering the combustion chamber, and the quick shut-off valve is used to prevent the compressed air from entering the combustion chamber and causing overspeed expansion of the combustion chamber turbine and the power turbine.

3. The wet air turbine cycle cogeneration system according to claim 1, characterized in that: At least one drain valve is provided on the humidifier, and the drain valve is used to drain water when the system is in a non-working state or an emergency state to avoid accidents.

4. The wet air turbine cycle cogeneration system according to claim 1, characterized in that: The exhaust port of the chimney is communicated with the atmosphere.

5. The wet air turbine cycle cogeneration system according to claim 1, characterized in that: The system adjusts the air ratio of the compressor's exhaust gas distributed to the regenerator and the combustion chamber through the first regulating valve and the second regulating valve, and adjusts the hot water flow distributed from the cold side of the economizer to the external heating component and the humidifier through the third regulating valve.

6. The wet air turbine cycle cogeneration system according to claim 5, characterized in that: When there is no heat load demand on the user side, the connecting pipeline between the cold side of the economizer and the external heating component is closed by the third regulating valve, and the proportion of external heating is 0 at this time; when there is a heat load demand on the user side, the opening of the third regulating valve is gradually adjusted to gradually increase the proportion of external hot water supplied from the cold side of the economizer to the external heating component, until the proportion of external heating is 1, that is, all hot water is supplied to the outside and hot water supply to the humidifier is stopped.

7. The wet air turbine cycle cogeneration system according to claim 6, characterized in that: When the heat load demand on the user side further increases, the opening of the first regulating valve is increased and the opening of the second regulating valve is reduced to reduce the proportion of the compressor's exhaust gas distributed to the aftercooler and the humidifier, so as to further increase the external heating amount.

8. The wet air turbine cycle combined heat and power system according to claim 2, characterized in that: When the system encounters a load shedding condition, the first check valve is used to prevent compressed air from flowing back into the compressor and causing surge, and the second check valve is used to prevent compressed air from entering the combustion chamber. The air intake line of the combustion chamber is quickly shut off by the quick shut-off valve to prevent compressed air from entering the combustion chamber and causing overspeed expansion of the combustion chamber turbine and the power turbine, thereby ensuring the safety of the system under load shedding conditions.

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