Steam turbine thermodynamic system based on state reconstruction, design method and operation method

Abstract

The invention provides a steam turbine thermodynamic system based on state reconstruction, a design method and an operation method.The thermodynamic system comprises at least one first acting cylinder body and at least one second acting cylinder body, and one first acting cylinder body and one corresponding second acting cylinder body form a reconstruction cylinder set; the reconstruction cylinder group is configured to control one acting cylinder body to be coupled into the thermal acting shaft system and the other acting cylinder body to be decoupled from the thermal acting shaft system based on a load working condition factor; by monitoring and controlling the load working condition factors, the acting cylinder body more suitable for the current load working condition is coupled into the thermal acting shaft system to play a better thermal effect, and the acting cylinder body not suitable for the current load working condition is decoupled from the thermal acting shaft system to realize more flexible load management and thermal efficiency optimization.

Description

Technical Field

[0001] The present invention belongs to the technical field of steam turbine power generation, and in particular relates to a steam turbine thermal system based on state reconstruction, a design method and an operation method. Background Art

[0002] Traditional steam turbine thermal systems are widely used in power generation and industrial production around the world. Their main advantages are large-scale energy conversion and long-term stable operation. However, with the changing demand of the energy market and the continuous integration of renewable energy, steam turbine systems are facing more and more challenges, especially in terms of load regulation performance, safety performance and energy efficiency.

[0003] In traditional systems, steam turbines are often designed to operate most efficiently under conditions close to full load. When the system operates under low load conditions, the unit operating parameters seriously deviate from the design conditions, resulting in a significant drop in the thermal system cycle efficiency, a significant drop in the operating efficiency of the steam turbine, and a significant drop in the safety and reliability of key components; at the same time, other key equipment involved in the thermal system, such as boilers, also face a significant drop in safety, reliability, and pollutant emission control.

[0004] In addition, when traditional steam turbines respond to load changes under low-load conditions, they cannot be adjusted deeply due to a significant decrease in safety and reliability, and are difficult to adjust effectively due to a significant deviation from the rated operating conditions of the thermal system and steam distribution system, which poses a challenge to the stability and reliability of the power grid. Most of the existing peak-shaving and frequency-regulating technical solutions rely on mechanical regulation and control system adjustments, which have inherent physical limitations and are difficult to efficiently respond to the urgent need for rapid regulation of the power grid. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a turbine thermal system, design method and operation method based on state reconstruction, which are mainly used to solve the problems of low thermal efficiency, poor safety and reliability, slow response efficiency, large adjustment restrictions, etc. of traditional thermal systems in the prior art when facing low load or variable load conditions.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a steam turbine thermal system based on state reconstruction, comprising at least one first working cylinder and at least one second working cylinder, wherein one of the first working cylinders and a corresponding one of the second working cylinders form a reconstructed cylinder group, and the reconstructed cylinder group is configured to control one of the working cylinders to couple into a thermal working shaft system based on a load condition factor, while the other working cylinder is decoupled from the thermal working shaft system.

[0008] In some embodiments, the number of the reconstructed cylinder groups is greater than 1, and different reconstructed cylinder groups correspond to different load condition factor control judgment reference values.

[0009] In some embodiments, the number of the reconstructed cylinder groups is greater than 1, and the load condition factor control judgment reference values ​​corresponding to different reconstructed cylinder groups are the same.

[0010] In some embodiments, the first working cylinder block and the second working cylinder block in the same reconfiguration cylinder group are arranged coaxially or eccentrically.

[0011] In some embodiments, the first working cylinder block and / or the second working cylinder block in the same reconfiguration cylinder group are connected to the ends of their corresponding thermal working shaft systems through a clutch.

[0012] In some embodiments, the first working cylinder and the second working cylinder in the same reconfiguration cylinder group have different pressure levels, and the flow characteristics of one working cylinder are equivalent to the flow characteristics of the corresponding pressure level of the front or rear area of ​​the other working cylinder.

[0013] In some embodiments, a medium-pressure cylinder is also included, the first working cylinder body is a first low-pressure cylinder, the second working cylinder body is a second low-pressure cylinder, the steam inlet end of the first low-pressure cylinder is connected to the steam exhaust end of the medium-pressure cylinder through a first valve, and the steam inlet end of the second low-pressure cylinder is connected to the steam exhaust end of the medium-pressure cylinder through a second valve, and the first valve and the second valve can be selectively opened and closed.

[0014] In some embodiments, the pressure level of the second low-pressure cylinder is less than that of the first low-pressure cylinder, and the flow characteristics of the second low-pressure cylinder are equivalent to the flow characteristics of the corresponding pressure level of the front area of ​​the first low-pressure cylinder.

[0015] In some embodiments, the first low-pressure cylinder and the second low-pressure cylinder are arranged coaxially or eccentrically.

[0016] In some embodiments, the first low-pressure cylinder and / or the second low-pressure cylinder is connected to the end of its corresponding thermal power shaft system through a low-pressure stage clutch.

[0017] In some embodiments, the intermediate pressure cylinder and the first low pressure cylinder are coaxially arranged, the first low pressure cylinder is connected to the end of the first thermal power shaft system through a low pressure stage clutch, and the second low pressure cylinder is arranged in the second thermal power shaft system.

[0018] In some embodiments, the intermediate pressure cylinder and the second low pressure cylinder are coaxially arranged, the second low pressure cylinder is connected to the end of the first thermal power shaft system through a low pressure stage clutch, and the first low pressure cylinder is arranged in the second thermal power shaft system.

[0019] In some embodiments, a reheater is also included, the first working cylinder is a first high-pressure cylinder, the second working cylinder is a second high-pressure cylinder, the steam inlet end of the first high-pressure cylinder is connected to the main steam through a third valve, the exhaust steam of the first high-pressure cylinder is connected to the reheater through a fourth valve, the steam inlet end of the second high-pressure cylinder is connected to the main steam through a fifth valve, and the exhaust steam end of the second high-pressure cylinder is connected to the reheater through a sixth valve, and the third valve, the fourth valve, the fifth valve and the sixth valve can be selectively opened and closed.

[0020] In some embodiments, the pressure level of the second high-pressure cylinder is greater than that of the first high-pressure cylinder, and the flow characteristics of the first high-pressure cylinder are comparable to the flow characteristics of the corresponding pressure level of the rear area of ​​the second high-pressure cylinder.

[0021] In some embodiments, the first high-pressure cylinder and the second high-pressure cylinder are arranged coaxially or eccentrically.

[0022] In some embodiments, the first high-pressure cylinder and / or the second high-pressure cylinder are connected to the end of the corresponding thermal power shaft system through a high-pressure stage clutch.

[0023] In a second aspect, the present invention provides a design method for a steam turbine thermal system applied to at least some of the above embodiments, wherein the design pressure of the condenser is P under 100% rated load condition. n , the rated steam inlet pressure of the first low-pressure cylinder is P L1 , the rated steam inlet flow rate of the first low-pressure cylinder is m L1 , determine the load condition factor control judgment reference value of state reconstruction as load rate L x1 ;

[0024] With load rate L x1 The working condition is the rated load condition of the second low-pressure cylinder. The rated steam inlet mass flow rate m of the second low-pressure cylinder is determined by verification. L2 and rated steam inlet pressure P L2 ;

[0025] According to the inlet steam mass flow rate m L2 , Rated steam inlet pressure P L2 and condenser pressure P n , check and design the flow structure of the second low-pressure cylinder.

[0026] In a third aspect, the present invention provides a design method for a steam turbine thermal system applied to at least some of the above embodiments, wherein, under a 100% rated load condition, the rated main steam flow of the first high-pressure cylinder is m1, the rated main steam pressure of the first high-pressure cylinder is P1, and the rated exhaust pressure of the first high-pressure cylinder is P b , determine the load condition factor control judgment reference value of state reconstruction as load rate L x2 ;

[0027] With load rate L x2 The working condition is the rated load condition of the second high-pressure cylinder. The rated main steam flow m2 of the second high-pressure cylinder is checked and determined. The rated exhaust steam pressure P of the second high-pressure cylinder is checked and determined. b2 ;

[0028] According to the rated main steam flow m2, the rated steam inlet pressure P1 and the rated exhaust pressure P b2 , check and design the flow structure of the second high-pressure cylinder.

[0029] In a fourth aspect, the present invention provides an operating method of a steam turbine thermal system applied to at least some of the above embodiments,

[0030] Select a group of reconstructed cylinder groups, set the load condition factor control judgment reference value corresponding to the reconstructed cylinder group as L0, and the transition zone load fluctuation range ΔL0, set the high load condition as (L0+ΔL0, A0%], the low load condition as [B0%, L0-ΔL0], the upper transition zone load condition as (L0, L0+ΔL0], and the lower transition zone load condition as (L0-ΔL0, L0];

[0031] Determine the load condition interval in which the current load condition factor is located;

[0032] If the working condition is high load, the first working cylinder in the reconstructed cylinder group is coupled into the thermal working shaft system, and the second working cylinder is decoupled from the thermal working shaft system;

[0033] If it is in a low-load condition, the second working cylinder in the reconstructed cylinder group is coupled into the thermal working shaft system, and the first working cylinder is decoupled from the thermal working shaft system.

[0034] Under the load condition in the upper transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in the steady state condition, it is executed in accordance with the high load condition;

[0035] Under the load condition in the lower transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in a steady-state condition, it is executed in accordance with the low-load condition.

[0036] In a fifth aspect, the present invention provides an operating method of a steam turbine thermal system applied to at least some of the above embodiments,

[0037] For the low-pressure reconstructed cylinder group, the corresponding load condition factor control judgment reference value is set to L1, and the load fluctuation range in the transition zone is ΔL1;

[0038] The high load condition is set to (L1+ΔL1, A1%], the low load condition is set to [B1%, L1-ΔL1], the upper transition zone load condition is set to (L1, L1+ΔL1], and the lower transition zone load condition is set to (L1-ΔL1, L1];

[0039] Determine the load condition interval in which the current load condition factor is located;

[0040] If it is under high load condition, open the first valve and close the second valve, so that the steam passes through the intermediate pressure cylinder and the first low pressure cylinder in sequence;

[0041] If it is under low load condition, open the second valve and close the first valve, so that the steam passes through the medium pressure cylinder and then enters the second low pressure cylinder;

[0042] Under the load condition in the upper transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in the steady state condition, it is executed in accordance with the high load condition;

[0043] Under the load condition in the lower transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in a steady-state condition, it is executed in accordance with the low-load condition.

[0044] In a sixth aspect, the present invention provides an operation method of a steam turbine thermal system applied to at least some of the above embodiments,

[0045] For the high-pressure reconstructed cylinder group, the corresponding load condition factor control judgment reference value is set to L2, and the load fluctuation range of the transition zone is ΔL2;

[0046] The high load condition is set to (L2+ΔL2, A2%], the low load condition is set to [B2%, L2-ΔL2]; the upper transition zone load condition is set to (L2, L2+ΔL2], and the lower transition zone load condition is set to (L2-ΔL2, L2];

[0047] Determine the load condition interval in which the current load condition factor is located;

[0048] If it is under high load condition, open the third valve and the fourth valve, close the fifth valve and the sixth valve, so that the main steam directly enters the first high-pressure cylinder and then is discharged into the reheater;

[0049] If it is under low load condition, open the fifth and sixth valves, close the third and fourth valves, so that the main steam directly enters the second high-pressure cylinder and then is discharged into the reheater;

[0050] Under the load condition in the upper transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in the steady state condition, it is executed in accordance with the high load condition;

[0051] Under the load condition in the lower transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in a steady-state condition, it is executed in accordance with the low-load condition.

[0052] Compared with the prior art, the present invention has at least the following beneficial effects:

[0053] 1. By introducing the concept of state reconstruction, the steam turbine thermal system can dynamically adjust its structure according to the changes in load conditions to fully optimize the operating parameters of the thermal system, thereby greatly improving the safety and reliability, operating thermal efficiency, load response characteristics and operating economy of the thermal system under different load conditions; compared with the traditional steam turbine thermal system, the present invention can ensure the safe and reliable operation of the unit within a larger load range, maintain a higher thermal efficiency, reduce energy loss, and reduce fuel consumption, and has a significant energy-saving effect;

[0054] 2. The design of the reconstructed cylinder group can flexibly control the coupling and decoupling of the working cylinder, realize the rapid reconstruction of the thermal system state, and greatly improve the system's adaptability and response speed to load changes; compared with the conventional steam turbine regulation method, the present invention can adjust the system structure under lower load conditions to make the unit operate in a new optimal operating range, thereby greatly improving the comprehensive regulation performance of the unit;

[0055] 3. The design methods for different types of reconstructed cylinder groups are proposed, which provide comprehensive design guidance for realizing state-reconstructed steam turbine thermal systems. By reasonably matching the structural parameters and operating parameters of the reconstructed cylinder groups, the operating conditions of the thermal system can be reconstructed under different load conditions, maximizing the efficiency advantages of each working cylinder and improving the overall performance of the system. The design method provided by the present invention is universal and targeted, and can be widely used in the optimization design of various steam turbine thermal systems.

[0056] 4. The corresponding operation method is given, and the working state of the reconstructed cylinder group can be adjusted in real time according to the changes in the load condition factors to ensure that the system always operates under the optimal working conditions; compared with the traditional operation control strategy, the present invention can accurately judge the load characteristics, automatically select the best system configuration and operating parameters, avoid human operation errors, and improve the intelligent level and reliability of operation; at the same time, the present invention can also be combined with the existing monitoring and fault diagnosis system to realize real-time supervision and safety protection of the state reconstruction process;

[0057] 5. The present invention has good versatility and scalability. It is not only suitable for the design of new steam turbine units, but also for the transformation and upgrading of existing steam turbine units. By reconstructing the state of the existing steam turbine thermal system, its operating flexibility and economy can be significantly improved, the life of the unit can be extended, and the life cycle cost can be reduced. The present invention provides new technical means and implementation paths for energy-saving transformation and green development in the power industry, and has certain applicability to new units or existing units with sufficient site space.

[0058] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The present invention is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0060] Figure 1 The present invention is a schematic structural diagram of a steam turbine thermal system based on state reconstruction in an embodiment. DETAILED DESCRIPTION

[0061] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0063] In the description of the present invention, when it is described that a specific device is located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device. When it is described that a specific device is connected to other devices, the specific device may be directly connected to the other devices without an intermediate device, or may not be directly connected to the other devices but have an intermediate device.

[0064] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0065] Embodiment 1:

[0066] Combination Figure 1 This embodiment 1 provides a steam turbine thermal system based on state reconstruction, including at least one first working cylinder and at least one second working cylinder, a first working cylinder and a corresponding second working cylinder form a reconstructed cylinder group, and the reconstructed cylinder group is configured to control one of the working cylinders to couple into the thermal working shaft system based on a load condition factor, while the other working cylinder is decoupled from the thermal working shaft system.

[0067] Specifically, when the load condition factor is higher than a certain reference value, the first working cylinder is controlled to be coupled into the thermal working axis system, and the second working cylinder is decoupled; when the load condition factor is lower than the reference value, the second working cylinder is controlled to be coupled into the thermal working axis system, and the first working cylinder is decoupled. In this way, the structure and operating parameters of the thermal system can be dynamically adjusted according to changes in load demand, and a high operating efficiency can be always maintained.

[0068] As an implementation mode, the number of reconstructed cylinder groups is greater than 1, and the reconstructed cylinder groups are divided according to the pressure operating range into high-pressure reconstructed cylinder groups and low-pressure reconstructed cylinder groups, and the load condition factor control judgment reference values ​​corresponding to different reconstructed cylinder groups are different; preferably, the load condition factor control judgment reference value is a pressure value or a load rate.

[0069] As another embodiment, the number of reconstructed cylinder groups is greater than 1, and the reconstructed cylinder groups are divided according to the pressure operating range into high-pressure reconstructed cylinder groups and low-pressure reconstructed cylinder groups, and the load condition factor control judgment reference values ​​corresponding to different reconstructed cylinder groups are the same; preferably, the load condition factor control judgment reference value is a pressure value or a load rate.

[0070] As an implementation method, the first working cylinder body and the second working cylinder body in the same reconstructed cylinder group are coaxially arranged, that is, the same reconstructed cylinder group uses a common thermal working shaft system. The working cylinder body that is put into operation is connected to the end of this thermal working shaft system through the corresponding clutch, while the working cylinder body that does not need to be put into operation controls the corresponding clutch to decouple from the end of this thermal working shaft system.

[0071] The benefits of coaxial arrangement are:

[0072] 1. Space and cost efficiency: The coaxial arrangement can reduce the required space because the two working cylinders share a working shaft system, reducing the need for additional shaft systems. This arrangement helps to simplify the structure, thereby also helping to reduce manufacturing and maintenance costs.

[0073] 2. Simplified structure: Compared with the design of multiple shaft systems, sharing a thermal work shaft system can simplify the mechanical design and construction, reduce the complexity of the system, and help improve the reliability of the system and reduce the failure rate.

[0074] 3. Maintenance convenience: Due to the coaxial arrangement of the working cylinder and the shaft system, maintenance work (such as inspection, replacement of parts, etc.) will be more centralized and simple, reducing the maintenance difficulty and cost in long-term operation.

[0075] As another embodiment, the first working cylinder body and the second working cylinder body in the same reconstructed cylinder group are arranged in a different axis. That is, the two working cylinder bodies in the same reconstructed cylinder group are respectively connected to two thermal working shaft systems, and the coupling and decoupling relationship between the working cylinder body and the corresponding thermal working shaft system is controlled based on the load condition factor.

[0076] The advantages of different axis arrangement are:

[0077] 1. Vibration and thermal stress management: Separated shafting can better control vibration and transmitted thermal stress, thereby reducing mechanical fatigue and extending equipment life.

[0078] 2. Scalability and modularity: The different axis arrangement provides more flexibility when the system needs to be upgraded or expanded in the future. New working cylinders and shaft systems can be added independently according to the additional energy requirements without having to make major modifications to the existing system.

[0079] 3. Flexibility of operation and maintenance: The different shaft arrangement allows each working cylinder to be maintained and repaired independently without affecting the operation of the other shaft system. This greatly reduces the possible operation interruption time during maintenance and improves production efficiency.

[0080] In the above two embodiments, the first working cylinder and / or the second working cylinder in the same reconstructed cylinder group are connected to the end of the corresponding thermal working shaft system through a clutch. The clutch allows the working cylinder to be quickly coupled or decoupled from the thermal working shaft system, which has extremely high flexibility and response speed. The clutch connection makes the switching of the working cylinder more rapid and flexible. When the load demand changes, the working cylinder suitable for the current load can be quickly selected through the clutch without complicated operations, thereby improving the system's response speed and ability to adapt to changes. Such a design allows the system to quickly adjust the operating state according to changes in load conditions and improve the response speed to load changes. The clutch can effectively control mechanical stress during the connection and disconnection process, reduce wear and impact that may be caused by direct mechanical connection, extend the service life of the equipment, and reduce maintenance costs; it also enhances modularity and scalability, and can add new working cylinders or upgrade the system without affecting existing operations.

[0081] In this embodiment, a similar pressure stage enthalpy drop design scheme is adopted under rated operating conditions, the pressure stages of the first working cylinder and the second working cylinder in the same reconstructed cylinder group are different, and the flow characteristics of one working cylinder are equivalent to the flow characteristics of the corresponding pressure stage of the front or rear area of ​​the other working cylinder.

[0082] Working cylinders with different pressure levels can flexibly respond to different operating pressure and temperature conditions, allowing the system to work effectively within a wide range of operating conditions. For example, when the grid load is low, working cylinders with low pressure levels can be used to reduce steam loss and improve thermal efficiency; and when the load demand is high, the working cylinders with high pressure levels can be switched to provide higher power output.

[0083] Matching the flow characteristics of one working cylinder with the pressure level of another working cylinder helps to more effectively distribute and utilize steam between the two working cylinders. The flow characteristics of the working cylinders affect the flow rate and pressure drop of the steam. If the flow characteristics of the two working cylinders can be matched, it can ensure that the pressure and temperature losses of the steam during the transmission process are minimized. This fine matching means that the steam can convert more of its thermal energy into mechanical energy during the expansion process, thereby improving the efficiency of the entire system. By precisely controlling the use of steam, the system can achieve higher thermal efficiency and reduce energy waste.

[0084] When power demand changes, the system needs to be able to respond quickly to these changes to maintain operating efficiency. By ensuring that the flow characteristics between the working cylinders match, the operating state of each cylinder can be adjusted more flexibly to adapt to changes in load. This design enables the system to transition quickly and stably when switching loads, improving the system's adaptability and dynamic performance to load fluctuations.

[0085] It should be noted that in some possible embodiments, similar pressure stage enthalpy drop design schemes are not adopted, and the pressure stages of the first working cylinder and the second working cylinder in the same reconstructed cylinder group can be designed arbitrarily, including the same and different situations.

[0086] Working principle description:

[0087] Under high load conditions, the load condition factor is higher than the reference value. At this time, the first working cylinder is controlled to couple into the thermal working shaft system, and the second working cylinder is decoupled. The steam mainly expands and works in the first working cylinder, and the system operates at a larger flow rate to meet high load requirements.

[0088] Under low load conditions, the load condition factor is lower than the reference value. At this time, the second working cylinder is controlled to couple into the thermal working shaft system, and the first working cylinder is decoupled. The steam mainly expands and works in the second working cylinder, and the system operates at a smaller flow rate to adapt to low load requirements.

[0089] During the load condition conversion process, the first working cylinder and the second working cylinder can be quickly switched through the action of the clutch to ensure the smooth operation of the system.

[0090] Embodiment 2:

[0091] Combination Figure 1 , this embodiment 2 provides a steam turbine thermal system based on state reconstruction. On the basis of embodiment 1, it is further limited to also include an intermediate pressure cylinder 1, the first working cylinder body is the first low pressure cylinder 2, the second working cylinder body is the second low pressure cylinder 4, the first low pressure cylinder 2 and the second low pressure cylinder 4 form a low pressure reconstruction cylinder group, the steam inlet end of the first low pressure cylinder 2 is connected to the exhaust end of the intermediate pressure cylinder 1 through the first valve 3, and the steam inlet end of the second low pressure cylinder 4 is connected to the exhaust end of the intermediate pressure cylinder 1 through the second valve 5. The first valve 3 and the second valve 5 can be selectively opened and closed to control the steam flow to the first low pressure cylinder 2 or the second low pressure cylinder 4.

[0092] In this embodiment, a similar pressure stage enthalpy drop design is adopted under rated working conditions, the pressure stage of the second low-pressure cylinder 4 is less than that of the first low-pressure cylinder 2, and the flow characteristics of the second low-pressure cylinder 4 are equivalent to the flow characteristics of the corresponding pressure stage of the front area of ​​the first low-pressure cylinder 2. In this way, the work capacity of the entire area of ​​the second low-pressure cylinder 4 can be fully utilized under low-load conditions, thereby improving steam utilization.

[0093] In terms of arrangement, the first low-pressure cylinder 2 and the second low-pressure cylinder 4 are arranged coaxially or eccentrically. At the same time, the first low-pressure cylinder 2 and / or the second low-pressure cylinder 4 are connected to the end of the corresponding thermal power shaft system through the low-pressure stage clutch 7.

[0094] As an implementation mode, the intermediate pressure cylinder 1 and the first low pressure cylinder 2 are coaxially arranged, the first low pressure cylinder 2 is connected to the end of the first thermal working shaft system through the low pressure stage clutch 7, the second low pressure cylinder 4 is arranged in the second thermal working shaft system, and the second low pressure cylinder 4 is off-axis arranged.

[0095] As an implementation mode, the intermediate pressure cylinder 1 and the second low pressure cylinder 4 are coaxially arranged, the second low pressure cylinder 4 is connected to the end of the first thermal working shaft system through the low pressure stage clutch 7, the first low pressure cylinder 2 is arranged in the second thermal working shaft system, and the first low pressure cylinder 2 is off-axis arranged.

[0096] Working principle:

[0097] Under high load conditions, the first valve 3 is opened and the second valve 5 is closed. After the steam is discharged from the intermediate pressure cylinder 1, it mainly enters the first low pressure cylinder 2 to perform work, and the system operates at a relatively large flow rate.

[0098] Under low load conditions, the second valve 5 is opened and the first valve 3 is closed. After the steam is discharged from the intermediate pressure cylinder 1, it mainly enters the second low pressure cylinder 4 to perform work, and the system operates at a relatively small flow rate.

[0099] Through the switching of valves and the action of the clutch, the state of the low-pressure cylinder can be reconstructed to adapt to different load requirements.

[0100] Embodiment 3:

[0101] Combination Figure 1 , this embodiment 3 provides a steam turbine thermal system based on state reconstruction. On the basis of embodiment 1, it is further limited to also include a boiler 8 and a reheater 13. The boiler 8 is used to generate main steam. The reheater 13 is arranged in the boiler 8 and is used to reheat the steam. Specifically, the first working cylinder body is the first high-pressure cylinder 9, and the second working cylinder body is the second high-pressure cylinder 10. The first high-pressure cylinder 9 and the second high-pressure cylinder 10 form a high-pressure reconstruction cylinder group. The steam inlet end of the first high-pressure cylinder 9 is connected to the main steam through the third valve 11, and the exhaust steam of the first high-pressure cylinder 9 is connected to the reheater 13 through the fourth valve 12. The steam inlet end of the second high-pressure cylinder 10 is connected to the main steam through the fifth valve 14, and the exhaust end of the second high-pressure cylinder 10 is connected to the reheater 13 through the sixth valve 15. The third valve 11, the fourth valve 12, the fifth valve 14 and the sixth valve 15 can be selectively turned on and off to control the main steam to flow to the first high-pressure cylinder 9 or the second high-pressure cylinder 10, and the exhaust steam of the high-pressure cylinder flows to the reheater 13.

[0102] In this embodiment, a similar pressure stage enthalpy drop design is adopted under rated working conditions, the pressure stage of the second high-pressure cylinder 10 is greater than that of the first high-pressure cylinder 9, and the flow characteristics of the first high-pressure cylinder 9 are equivalent to the flow characteristics of the corresponding pressure stage of the rear area of ​​the second high-pressure cylinder 10. In this way, the work capacity of the entire area of ​​the second high-pressure cylinder 10 can be fully utilized under high-load conditions, thereby improving the main steam utilization rate.

[0103] In terms of arrangement, the first high-pressure cylinder 9 and the second high-pressure cylinder 10 are arranged coaxially or eccentrically. At the same time, the first high-pressure cylinder 9 and / or the second high-pressure cylinder 10 are connected to the end of the corresponding thermal power shaft system through the high-pressure stage clutch 16.

[0104] Working principle:

[0105] Under high load conditions, the third valve 11 and the fourth valve 12 are opened, and the fifth valve 14 and the sixth valve 15 are closed. The main steam mainly enters the first high-pressure cylinder 9 to perform work, and the exhaust steam enters the reheater 13 for reheating.

[0106] Under low load conditions, the fifth valve 14 and the sixth valve 15 are opened, and the third valve 11 and the fourth valve 12 are closed. The main steam mainly enters the second high-pressure cylinder 10 to perform work, and the exhaust steam enters the reheater 13 for reheating.

[0107] Through the switching of valves and the action of the clutch, the state of the high-pressure cylinder can be reconstructed to adapt to different load requirements while ensuring the stability of the reheat steam parameters.

[0108] Embodiment 4:

[0109] This embodiment 4 provides a design method for the steam turbine thermal system in embodiment 2. Under rated conditions, a similar pressure stage enthalpy drop design scheme is adopted. Under 100% rated load conditions, the design pressure of the condenser 6 is set to P n , the rated steam inlet pressure of the first low-pressure cylinder 2 is P L1 , the rated steam flow rate of the first low-pressure cylinder 2 is m L1 , determine the load condition factor control judgment reference value of state reconstruction as load rate L x1 ;

[0110] With load rate L x1 The working condition is the rated load condition of the second low-pressure cylinder 4, and the rated steam inlet mass flow rate m of the second low-pressure cylinder 4 is verified and determined. L2 and rated steam inlet pressure P L2 ;

[0111] According to the inlet steam mass flow rate m L2 , Rated steam inlet pressure P L2 and condenser 6 pressure P n , check and design the flow structure of the second low-pressure cylinder 4.

[0112] By setting a rated load condition for the second low-pressure cylinder 4 based on the actual operating data of the first low-pressure cylinder 2, the performance requirements of the steam turbine at different operating points can be more accurately matched. This method allows the second low-pressure cylinder 4 to operate in its optimal operating area, maximizing thermal efficiency and output power while reducing energy waste. Specifically, by adjusting the inlet steam mass flow rate and pressure, the second low-pressure cylinder 4 can maintain the best steam expansion efficiency under different loads.

[0113] Used load factor L x1 As a design and verification benchmark, the design of the second low-pressure cylinder 4 can adapt to changing load conditions. This adaptability is achieved by ensuring that optimized performance can be maintained under different operating loads, thereby enhancing the turbine's ability to respond to changes in grid demand.

[0114] By ensuring that the second low-pressure cylinder 4 operates efficiently at a load point customized according to actual operating conditions, mechanical damage caused by excessive wear or improper operation can be reduced. The design that adapts to different loads reduces the need for frequent mechanical adjustments and maintenance, thereby extending the service life of the equipment and reducing maintenance costs.

[0115] Embodiment 5:

[0116] This embodiment 5 provides a design method for the steam turbine thermal system in embodiment 3. Under rated conditions, a similar pressure stage enthalpy drop design scheme is adopted. Under 100% rated load conditions, the rated main steam flow of the first high-pressure cylinder 9 is m1, the rated main steam pressure of the first high-pressure cylinder 9 is P1, and the rated exhaust pressure of the first high-pressure cylinder 9 is P b , determine the load condition factor control judgment reference value of state reconstruction as load rate L x2 ;

[0117] With load rate L x2 The working condition is the rated load condition of the second high-pressure cylinder 10. The rated main steam flow m2 of the second high-pressure cylinder 10 is checked and determined. The rated exhaust steam pressure P of the second high-pressure cylinder 10 is checked and determined. b2 ;

[0118] According to the rated main steam flow m2, the rated steam inlet pressure P1 and the rated exhaust pressure P b2 , check and design the flow structure of the second high-pressure cylinder 10.

[0119] By setting a specific load rate L for the second high-pressure cylinder 10 with reference to the first high-pressure cylinder 9 x2 This design method allows the second high-pressure cylinder 10 to be optimized for different operating requirements. This flexibility allows the steam turbine to operate effectively under a variety of operating conditions, especially in power systems with large load changes, to quickly adapt to demand changes and maintain efficient operation.

[0120] By accurately checking the main steam flow m2 and exhaust pressure P of the second high-pressure cylinder 10 b2 , you can ensure that the cylinder's operating parameters are best suited to its design load.

[0121] This design strategy contributes to a more reasonable steam flow and pressure distribution by re-evaluating and setting the steam inlet pressure and exhaust pressure of the second high-pressure cylinder 10 according to actual operating data. This can not only improve the utilization efficiency of steam, but also reduce heat loss and mechanical stress, thereby extending the service life of the equipment.

[0122] Embodiment 6:

[0123] This embodiment 6 provides an operation method for the steam turbine thermal system in the above embodiment 1:

[0124] Select a group of reconstructed cylinder groups, set the load condition factor control judgment reference value corresponding to the reconstructed cylinder group as L0, and the transition zone load fluctuation range ΔL0, set the high load condition as (L0+ΔL0, A0%], the low load condition as [B0%, L0-ΔL0], the upper transition zone load condition as (L0, L0+ΔL0], and the lower transition zone load condition as (L0-ΔL0, L0];

[0125] Determine the load condition interval in which the current load condition factor is located;

[0126] If the working condition is high load, the first working cylinder in the reconstructed cylinder group is coupled into the thermal working shaft system, and the second working cylinder is decoupled from the thermal working shaft system;

[0127] If it is in a low-load condition, the second working cylinder in the reconstructed cylinder group is coupled into the thermal working shaft system, and the first working cylinder is decoupled from the thermal working shaft system.

[0128] Under the load condition in the upper transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in the steady state condition, it is executed in accordance with the high load condition;

[0129] Under the load condition in the lower transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in a steady-state condition, it is executed in accordance with the low-load condition.

[0130] It should be noted that the load condition factor control judgment reference values ​​L0 of different reconfigured cylinder groups may be the same or different, which is not limited in the present embodiment.

[0131] Embodiment 7:

[0132] This embodiment 7 provides an operation method for the steam turbine thermal system in the above embodiment 2:

[0133] For the low-pressure reconstructed cylinder group, the corresponding load condition factor control judgment reference value is set to L1, and the load fluctuation range in the transition zone is ΔL1;

[0134] The high load condition is set to (L1+ΔL1, A1%], the low load condition is set to [B1%, L1-ΔL1], the upper transition zone load condition is set to (L1, L1+ΔL1], and the lower transition zone load condition is set to (L1-ΔL1, L1];

[0135] Determine the load condition interval in which the current load condition factor is located;

[0136] If it is under high load condition, open the first valve 3 and close the second valve 5, so that the steam passes through the intermediate pressure cylinder 1 and the first low pressure cylinder 2 in sequence;

[0137] If it is under low load condition, open the second valve 5 and close the first valve 3, so that the steam passes through the intermediate pressure cylinder 1 and then enters the second low pressure cylinder 4;

[0138] Under the load condition in the upper transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in the steady state condition, it is executed in accordance with the high load condition;

[0139] Under the load condition in the lower transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in a steady-state condition, it is executed in accordance with the low-load condition.

[0140] Embodiment 8:

[0141] This embodiment 8 provides an operation method for the steam turbine thermal system in the above embodiment 3:

[0142] For the high-pressure reconstructed cylinder group, the corresponding load condition factor control judgment reference value is set to L2, and the load fluctuation range of the transition zone is ΔL2;

[0143] The high load condition is set to (L2+ΔL2, A2%], the low load condition is set to [B2%, L2-ΔL2]; the upper transition zone load condition is set to (L2, L2+ΔL2], and the lower transition zone load condition is set to (L2-ΔL2, L2];

[0144] Determine the load condition interval in which the current load condition factor is located;

[0145] If it is under high load condition, open the third valve 11 and the fourth valve 12, close the fifth valve 14 and the sixth valve 15, so that the main steam directly enters the first high-pressure cylinder 9 and then is discharged into the reheater 13;

[0146] If it is under low load condition, open the fifth valve 14 and the sixth valve 15, close the third valve 11 and the fourth valve 12, so that the main steam directly enters the second high-pressure cylinder 10 and then is discharged into the reheater 13;

[0147] Under the load condition in the upper transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in the steady state condition, it is executed in accordance with the high load condition;

[0148] Under the load condition in the lower transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in a steady-state condition, it is executed in accordance with the low-load condition.

[0149] In Examples 6, 7, and 8, by setting the load fluctuation range ΔL in the transition zone and the corresponding upper transition zone and lower transition zone, the thermal system of the steam turbine can be more accurately adjusted to adapt to variable load conditions.

[0150] As an implementation method, in actual operation, the load state of the steam turbine will change with the change of demand. The system will monitor the current load condition factor in real time and determine the load condition interval (high load, low load, upper transition zone, lower transition zone, etc.) in which it is located. The setting of these intervals is based on the previously defined reference values ​​(L0, L1, L2) and their corresponding transition zone load fluctuation ranges (ΔL0, ΔL1, ΔL2). Therefore, on the basis of Examples 6, 7, and 8, this implementation method sets certain control algorithms and control schemes near the load close to the load condition factor control judgment reference value (such as L0, L1, L2), such as setting the overlap of the reconstructed cylinder group switching and setting the boundary zone load fluctuation range. Specifically:

[0151] Overlap setting of reconfigured cylinder group switching: In order to reduce the impact on system stability during load switching, the switching overlap between different reconfigured cylinder groups is set. This means that when one cylinder group is switched, another cylinder group will be partially involved to smooth the transition and avoid system vibration or instability caused by sudden load changes.

[0152] Setting of load fluctuation range in boundary area: When determining the current load status, the system will adjust the operation according to the set load fluctuation range in the upper and lower transition areas, which helps to maintain the flexibility and response speed of the system during load changes.

[0153] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A steam turbine thermal system based on state reconstruction, characterized in that: The invention comprises at least one first working cylinder and at least one second working cylinder, wherein one of the first working cylinders and a corresponding one of the second working cylinders form a reconstructed cylinder group, and the reconstructed cylinder group is configured to control one of the working cylinders to be coupled into a thermal working shaft system based on a load condition factor, while the other working cylinder is decoupled from the thermal working shaft system.

2. A steam turbine thermal system based on state reconstruction according to claim 1, characterized in that: The number of the reconstructed cylinder groups is greater than 1, and different reconstructed cylinder groups correspond to different load condition factor control judgment reference values.

3. A steam turbine thermal system based on state reconstruction according to claim 1, characterized in that: The number of the reconstructed cylinder groups is greater than 1, and the load condition factor control judgment reference values ​​corresponding to different reconstructed cylinder groups are the same.

4. A steam turbine thermal system based on state reconstruction according to claim 1, characterized in that: The first working cylinder block and the second working cylinder block in the same reconfiguration cylinder group are coaxially arranged or eccentrically arranged.

5. A steam turbine thermal system based on state reconstruction according to any one of claims 1 to 4, characterized in that: The first working cylinder block and / or the second working cylinder block in the same reconfiguration cylinder group are connected to the end of the corresponding thermal working shaft system through a clutch.

6. A steam turbine thermal system based on state reconstruction according to any one of claims 1 to 4, characterized in that: The pressure levels of the first working cylinder and the second working cylinder in the same reconfigured cylinder group are different, and the flow characteristics of one working cylinder are equivalent to the flow characteristics of the corresponding pressure level of the front or rear area of ​​the other working cylinder.

7. A steam turbine thermal system based on state reconstruction according to claim 1, characterized in that: It also includes a medium-pressure cylinder, the first working cylinder body is a first low-pressure cylinder, the second working cylinder body is a second low-pressure cylinder, the steam inlet end of the first low-pressure cylinder is connected to the steam exhaust end of the medium-pressure cylinder through a first valve, and the steam inlet end of the second low-pressure cylinder is connected to the steam exhaust end of the medium-pressure cylinder through a second valve, and the first valve and the second valve can be selectively opened and closed.

8. A steam turbine thermal system based on state reconstruction according to claim 7, characterized in that: The pressure level of the second low-pressure cylinder is less than that of the first low-pressure cylinder, and the flow characteristics of the second low-pressure cylinder are equivalent to the flow characteristics of the corresponding pressure level of the front area of ​​the first low-pressure cylinder.

9. A steam turbine thermal system based on state reconstruction according to claim 8, characterized in that: The first low-pressure cylinder and the second low-pressure cylinder are arranged coaxially or eccentrically.

10. A steam turbine thermal system based on state reconstruction according to claim 9, characterized in that: The first low-pressure cylinder and / or the second low-pressure cylinder are connected to the end of the corresponding thermal power shaft system through a low-pressure stage clutch.

11. A steam turbine thermal system based on state reconstruction according to claim 7 or 8, characterized in that: The intermediate pressure cylinder is coaxially arranged with the first low pressure cylinder. The first low pressure cylinder is connected to the end of the first thermal power shaft system through a low pressure stage clutch. The second low pressure cylinder is arranged in the second thermal power shaft system.

12. A steam turbine thermal system based on state reconstruction according to claim 7 or 8, characterized in that: The medium-pressure cylinder and the second low-pressure cylinder are coaxially arranged. The second low-pressure cylinder is connected to the end of the first thermal power shaft system through a low-pressure stage clutch. The first low-pressure cylinder is arranged in the second thermal power shaft system.

13. A steam turbine thermal system based on state reconstruction according to claim 1, characterized in that: It also includes a reheater, the first working cylinder body is a first high-pressure cylinder, the second working cylinder body is a second high-pressure cylinder, the steam inlet end of the first high-pressure cylinder is connected to the main steam through a third valve, the exhaust steam of the first high-pressure cylinder is connected to the reheater through a fourth valve, the steam inlet end of the second high-pressure cylinder is connected to the main steam through a fifth valve, and the exhaust steam end of the second high-pressure cylinder is connected to the reheater through a sixth valve, and the third valve, the fourth valve, the fifth valve and the sixth valve can be selectively opened and closed.

14. A steam turbine thermal system based on state reconstruction according to claim 13, characterized in that: The pressure level of the second high-pressure cylinder is greater than that of the first high-pressure cylinder, and the flow characteristics of the first high-pressure cylinder are equivalent to the flow characteristics of the corresponding pressure level of the rear area of ​​the second high-pressure cylinder.

15. A steam turbine thermal system based on state reconstruction according to claim 14, characterized in that: The first high-pressure cylinder and the second high-pressure cylinder are arranged coaxially or eccentrically.

16. A steam turbine thermal system based on state reconstruction according to claim 15, characterized in that: The first high-pressure cylinder and / or the second high-pressure cylinder are connected to the end of the corresponding thermal power shaft system through a high-pressure stage clutch.

17. A design method for a steam turbine thermal system according to any one of claims 7 to 12, characterized in that: Under the condition of 100% rated load, the design pressure of the condenser is P n , the rated steam inlet pressure of the first low-pressure cylinder is P L1 , the rated steam inlet flow rate of the first low-pressure cylinder is m L1 , determine the load condition factor control judgment reference value of state reconstruction as load rate L x1 ; With load rate L x1 The working condition is the rated load condition of the second low-pressure cylinder. The rated steam inlet mass flow rate m of the second low-pressure cylinder is determined by verification. L2 and rated steam inlet pressure P L2 ; According to the inlet steam mass flow rate m L2 , Rated steam inlet pressure P L2 and condenser pressure P n , check and design the flow structure of the second low-pressure cylinder.

18. A design method for a steam turbine thermal system according to any one of claims 13 to 16, characterized in that: Under the condition of 100% rated load, the rated main steam flow of the first high-pressure cylinder is m1, the rated main steam pressure of the first high-pressure cylinder is P1, and the rated exhaust pressure of the first high-pressure cylinder is P b , determine the load condition factor control judgment reference value of state reconstruction as load rate L x2 ; With load rate L x2 The working condition is the rated load condition of the second high-pressure cylinder. The rated main steam flow m2 of the second high-pressure cylinder is checked and determined. The rated exhaust steam pressure P of the second high-pressure cylinder is checked and determined. b2 ; According to the rated main steam flow m2, the rated steam inlet pressure P1 and the rated exhaust pressure P b2 , check and design the flow structure of the second high-pressure cylinder.

19. An operating method for a steam turbine thermal system according to any one of claims 1 to 6, characterized in that: Select a group of reconstructed cylinder groups, set the load condition factor control judgment reference value corresponding to the reconstructed cylinder group as L0, and the transition zone load fluctuation range ΔL0, set the high load condition as (L0+ΔL0, A0%], the low load condition as [B0%, L0-ΔL0], the upper transition zone load condition as (L0, L0+ΔL0], and the lower transition zone load condition as (L0-ΔL0, L0]; Determine the load condition interval in which the current load condition factor is located; If the working condition is high load, the first working cylinder in the reconstructed cylinder group is coupled into the thermal working shaft system, and the second working cylinder is decoupled from the thermal working shaft system; If it is in a low-load condition, the second working cylinder in the reconstructed cylinder group is coupled into the thermal working shaft system, and the first working cylinder is decoupled from the thermal working shaft system. Under the load condition in the upper transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in the steady state condition, it is executed in accordance with the high load condition; Under the load condition in the lower transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in a steady-state condition, it is executed in accordance with the low-load condition.

20. An operating method for a steam turbine thermal system according to any one of claims 7 to 12, characterized in that: For the low-pressure reconstructed cylinder group, the corresponding load condition factor control judgment reference value is set to L1, and the load fluctuation range in the transition zone is ΔL1; The high load condition is set to (L1+ΔL1, A1%], the low load condition is set to [B1%, L1-ΔL1], the upper transition zone load condition is set to (L1, L1+ΔL1], and the lower transition zone load condition is set to (L1-ΔL1, L1]; Determine the load condition interval in which the current load condition factor is located; If it is under high load condition, open the first valve and close the second valve, so that the steam passes through the intermediate pressure cylinder and the first low pressure cylinder in sequence; If it is under low load condition, open the second valve and close the first valve, so that the steam passes through the medium pressure cylinder and then enters the second low pressure cylinder; Under the load condition in the upper transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in the steady state condition, it is executed in accordance with the high load condition; Under the load condition in the lower transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in a steady-state condition, it is executed in accordance with the low-load condition.

21. An operating method for a steam turbine thermal system according to any one of claims 13 to 16, characterized in that: For the high-pressure reconstructed cylinder group, the corresponding load condition factor control judgment reference value is set to L2, and the load fluctuation range of the transition zone is ΔL2; The high load condition is set to (L2+ΔL2, A2%], the low load condition is set to [B2%, L2-ΔL2]; the upper transition zone load condition is set to (L2, L2+ΔL2], and the lower transition zone load condition is set to (L2-ΔL2, L2]; Determine the load condition interval in which the current load condition factor is located; If it is under high load condition, open the third valve and the fourth valve, close the fifth valve and the sixth valve, so that the main steam directly enters the first high-pressure cylinder and then is discharged into the reheater; If it is under low load condition, open the fifth and sixth valves, close the third and fourth valves, so that the main steam directly enters the second high-pressure cylinder and then is discharged into the reheater; Under the load condition in the upper transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in the steady state condition, it is executed in accordance with the high load condition; Under the load condition in the lower transition zone, if it is in the process of variable load, the unit structure is maintained unchanged; if it is in a steady-state condition, it is executed in accordance with the low-load condition.

Images