Double-circulation steam turbine system, adjusting method and thermodynamic system
By designing a dual-cycle steam turbine system, the circulation of steam and condensate is achieved through backup steam and return water pipelines. This solves the problem of steam flow deviation when the high-power, high-parameter steam turbine is running at low load, improves economy and load regulation efficiency, and achieves rapid response and stable operation.
Patent Information
- Application Number
- CN202511601279.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-04
- Publication Date
- 2025-12-16
AI Technical Summary
When a high-power, high-parameter steam turbine operates at low load and below rated power, the steam flow rate deviates from the design conditions, resulting in residual velocity loss and insufficient steam pressure and temperature, which affects economic efficiency. In particular, during peak shaving, large load changes lead to increased coal consumption.
The system employs a dual-cycle steam turbine system, comprising independent first and second cycle units. Steam and condensate are circulated through a standby steam pipeline and a standby return water pipeline. The second cycle unit responds quickly to load changes in hot standby mode, while the first cycle unit undertakes the main load and the second cycle unit starts up quickly when needed.
This improves the operating economy and load regulation efficiency of the steam turbine under different loads, reduces energy consumption, and enhances the load regulation response rate and overall machine operating stability.
Smart Images
Figure CN121139936A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of steam turbine equipment technology, and in particular to a dual-cycle steam turbine system, regulation method and thermal system. Background Technology
[0002] For high-power, high-parameter steam turbines, under low-load operation conditions below rated power, the dimensions, angles, and other parameters of the turbine blades at each stage cannot reach the design operating conditions, resulting in abnormal steam flow deviating from the design conditions. At the same time, there will be significant residual velocity loss and insufficient steam pressure and temperature. Especially during peak shaving, the turbine load changes significantly, leading to a significant decrease in the turbine's economic efficiency and an increase in coal consumption per unit of power generation. Summary of the Invention
[0003] In view of this, the purpose of this application is to provide a dual-cycle steam turbine system, regulation method and thermodynamic system to improve the economic efficiency of the steam turbine during operation under different load demands.
[0004] To achieve the above objectives, this application provides the following technical solution:
[0005] A dual-cycle steam turbine system, comprising:
[0006] The boiler comprises a first section and a second section with independent circulation.
[0007] The first circulation unit and the second circulation unit are symmetrically arranged about the boiler. The first circulation unit is cyclically connected to the first branch, and the second circulation unit is cyclically connected to the second branch.
[0008] A backup steam pipe and a backup return water pipe are connected between the first circulation unit and the second circulation unit. The second circulation unit can receive part of the steam separated from the first circulation unit through the backup steam pipe to be in a hot standby state, and return the condensate to the first circulation unit through the backup return water pipe.
[0009] Preferably, in the above-mentioned dual-cycle steam turbine system, the second cycle unit includes a second high-pressure cylinder and a second intermediate-pressure cylinder, and the standby steam pipeline branches into a first standby pipe and a second standby pipe, the first standby pipe being connected to the second high-pressure cylinder and the second standby pipe being connected to the second intermediate-pressure cylinder.
[0010] Preferably, in the above-mentioned dual-cycle steam turbine system, the second cycle unit further includes a second low-pressure cylinder, and the second intermediate-pressure cylinder and the second low-pressure cylinder are connected by a connecting pipe for steam to pass through.
[0011] Preferably, in the above-mentioned dual-cycle steam turbine system, the second cycle unit includes a second condenser, the second high-pressure cylinder is connected to the second condenser through a vacuum pipe, and the steam outlet of the second low-pressure cylinder is directly connected to the second condenser.
[0012] Preferably, in the above-mentioned dual-cycle steam turbine system, the second condenser is installed on the backup return water pipeline, and the backup return water pipeline is equipped with an auxiliary condensate pump whose driving direction is towards the first circulation unit.
[0013] Preferably, in the above-mentioned dual-cycle steam turbine system, the first cycle unit includes a first high-pressure cylinder and a first intermediate-pressure cylinder, and the first branch is connected to the first high-pressure cylinder through a first steam pipeline; the first high-pressure cylinder and the first intermediate-pressure cylinder are connected through a reheat steam pipeline, and a reheater is provided on the path of the reheat steam pipeline.
[0014] Preferably, in the above-mentioned dual-cycle steam turbine system, the first cycle unit further includes a first low-pressure cylinder, the first intermediate-pressure cylinder and the first low-pressure cylinder are connected through a low-pressure steam pipeline, and the first low-pressure cylinder is connected to the first section through a condensing pipeline equipped with a first condenser; the spare return water pipeline is connected to the first condenser or the condensing pipeline.
[0015] Preferably, in the above-mentioned dual-cycle steam turbine system, the expansion reference points of the rotor component and the stator component of the dual-cycle steam turbine system are set on the line of symmetry between the first high-pressure cylinder and the second high-pressure cylinder. The rotor component expands towards both ends with respect to the expansion reference point, and both the first high-pressure cylinder and the second high-pressure cylinder expand in a direction away from the expansion reference point.
[0016] Preferably, in the above-mentioned dual-cycle steam turbine system, the first high-pressure cylinder and the first intermediate-pressure cylinder are either a combined cylinder module or two independently configured modules.
[0017] A regulation method for regulating a dual-cycle steam turbine system as described in any of the preceding claims, the regulation method comprising:
[0018] High load regulation: When the operating load demand of the dual-cycle steam turbine system is 50% or above, the first section and the first circulation unit are regulated to operate at full power under rated steam parameters, and the second section and the second circulation unit are started synchronously and operated at a power not greater than that under rated steam parameters;
[0019] Low load adjustment: When the operating load demand of the dual-cycle steam turbine system is below 50%, the first section and the first cycle unit are adjusted to operate at the power required by the whole machine's operating load, while the second section and the second cycle unit are in the hot standby state.
[0020] Preferably, in the above-mentioned regulation method, when the dual-cycle steam turbine system is in high-load regulation operation state, the second cycle unit operates in constant pressure throttling mode or sliding pressure regulation mode.
[0021] A thermal system comprising a dual-cycle steam turbine system as described in any of the preceding claims.
[0022] As can be seen from the above technical solution, the dual-cycle steam turbine system provided in this disclosure mainly includes a boiler, a first circulation unit, and a second circulation unit. The boiler includes a first section and a second section with independent circulation, which can operate independently to provide superheated steam. The first circulation unit and the second circulation unit are independent circulation systems. The first circulation unit is cyclically connected to the first section, and the second circulation unit is cyclically connected to the second section. The load of the dual-cycle steam turbine system is borne by the first circulation unit and the second circulation unit in cooperation. When the operating load of the dual-cycle steam turbine system exceeds the design load of either the first circulation unit or the second circulation unit, the corresponding circulation unit can achieve its rated load. The first and second circulation units operate independently, while the total load is regulated through another circulation unit, resulting in good economic efficiency. Simultaneously, a backup steam pipeline and a backup return water pipeline connect the first and second circulation units. The second circulation unit can receive a portion of the steam diverted from the first circulation unit via the backup steam pipeline to maintain a hot standby state, and return condensate to the first circulation unit via the backup return water pipeline. When the operating load of the dual-cycle turbine system is low, the first circulation unit can meet the load demand. Simultaneously, the backup steam pipeline keeps the second circulation unit in a hot standby state when it stops operating, enabling rapid start-up and regulation of the second circulation unit during load regulation, thus improving the efficiency of the load regulation process of the dual-cycle turbine system. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a schematic diagram of a dual-cycle steam turbine system provided in an embodiment of the present disclosure;
[0025] Figure 2 for Figure 1 Schematic diagram of the surrounding structure of the boiler;
[0026] Figure 3This is a schematic diagram of the structure of the first division and the first circulation unit provided in an embodiment of the present disclosure;
[0027] Figure 4 This is a schematic diagram of the structure of the second division and the second circulation unit provided in an embodiment of the present disclosure.
[0028] in:
[0029] 10 - Boiler; 110 - First Division; 120 - Second Division;
[0030] 20 - First circulation unit; 210 - First high-pressure cylinder; 220 - First intermediate-pressure cylinder; 230 - First low-pressure cylinder; 240 - Reheat steam pipeline; 250 - Low-pressure steam pipeline; 260 - First condenser; 270 - Condensation pipeline; 2710 - Low-pressure heater; 2720 - Deaerator; 2730 - High-pressure heater;
[0031] 30 - Second circulation unit; 310 - Second high-pressure cylinder; 320 - Second intermediate-pressure cylinder; 330 - Second low-pressure cylinder; 340 - Connecting pipe; 350 - Second condenser; 360 - Vacuum extraction pipe;
[0032] 40 - Backup steam pipe; 410 - First backup pipe; 420 - Second backup pipe;
[0033] 50 - Backup return water pipe; 510 - Auxiliary condensate pump;
[0034] 60 - Expansion reference point. Detailed Implementation
[0035] The core of this application is to disclose a dual-cycle steam turbine system, regulation method, and thermodynamic system to improve the economic efficiency of the steam turbine during operation under different load demands.
[0036] To enable those skilled in the art to better understand the present application, embodiments of the present application will be described below with reference to the accompanying drawings. Furthermore, the embodiments shown below do not limit the scope of the invention as described in the claims. Additionally, the complete contents of the structures represented in the following embodiments are not limited to those necessary for the solution of the invention described in the claims.
[0037] like Figures 1-4As shown, this embodiment of the present disclosure provides a dual-cycle steam turbine system, which mainly includes a boiler 10, a first circulation unit 20, and a second circulation unit 30. The boiler 10 includes a first section 110 and a second section 120 with independent circulation. Here, independent circulation means that the first section 110 and the second section 120 of the boiler 10 can operate independently and have their operating parameters adjusted so that the first section 110 and the second section 120 can provide steam with different parameters. For this dual-cycle steam turbine system, its design full-load state is that the first section 110 and the second section 120 of the boiler 10 are simultaneously at their maximum operating load.
[0038] The first circulation unit 20 and the second circulation unit 30 are independently configured circulation systems with their own cylinders. Specifically, the first circulation unit 20 is cyclically connected to the first section 110, and the superheated steam provided by the first section 110 performs work through the first circulation unit 20. The second circulation unit 30 is cyclically connected to the second section 120, and the superheated steam provided by the second section 120 performs work through the second circulation unit 30. That is, for the dual-cycle steam turbine system, it has two independent circulation units, and the design load of the dual-cycle steam turbine system is the sum of the loads of the two circulation units.
[0039] It should be noted that in some embodiments, the first circulation unit 20 and the second circulation unit 30 are symmetrically arranged about the boiler 10, so that the structure of the dual-cycle steam turbine system is more regular. Preferably, the maximum operating load of the first section 110 and the second section 120 is the same, and the operating power of the first circulation unit 20 and the second circulation unit 30 is the same, so that the two independent cycles of the dual-cycle steam turbine system can have the same working effect. The load of the dual-cycle steam turbine system is borne by the first circulation unit 20 and the second circulation unit 30 respectively, each bearing 50%.
[0040] Based on the above structure, when the dual-cycle turbine system is operating at maximum load, both the first section 110 and the second section 120 can operate at maximum load, and the first cycle unit 20 and the second cycle unit 30 can operate at maximum power. When the operating load of the dual-cycle turbine system is 50% or higher, but has not reached the maximum operating load requirement, the dual-cycle turbine system can maintain one of the first cycle unit 20 and the second cycle unit 30 at maximum operating power to achieve 50% operating load requirement of the dual-cycle turbine system, thereby meeting the rated operating parameters and improving the operating economy of that cycle unit. The other cycle unit is adjusted according to the total load requirement to operate below the rated operating parameters.
[0041] When the operating load of the dual-cycle steam turbine system is below 50%, the load demand can be met by a single cycle unit. Taking the first cycle unit 20 as an example, when the operating load of the dual-cycle steam turbine system is below 50%, the first cycle unit 20 remains in operation, while the second cycle unit 30 and the second section 120 are in a hot standby state. Specifically, a standby steam pipe 40 and a standby return water pipe 50 are connected between the first cycle unit 20 and the second cycle unit 30. During the independent operation of the first cycle unit 20, the superheated steam provided by the first section 110 can partially reach the second cycle unit 30 through the standby steam pipe 40. The superheated steam passes through the cylinder of the second cycle unit 30, thus putting it in a hot standby state. At the same time, the steam passing through the second cycle unit 30 condenses and flows back to the first cycle unit 20 through the standby return water pipe 50 to participate in the circulation of the first cycle unit 20 and then flows back to the first section 110 of the boiler 10.
[0042] It should be noted that, in the above embodiments, the energy for the hot standby state of the second circulation unit 30 can be provided by the first section 110 and the first circulation unit 20, which are in operation. This not only reduces the energy consumption currently maintained in the hot standby state, but also allows the first section 110 to operate at a higher load, that is, to operate closer to 50% of the total load of the boiler 10, and closer to the rated load of the first section 110, thereby improving the operating economy of the first section 110. The second circulation unit 30 in the hot standby state can perform load regulation in the dual-cycle turbine system, and can achieve hot start when needed, while enabling the dual-cycle turbine system to adapt to frequently changing load operation requirements during the peak shaving phase.
[0043] The dual-cycle steam turbine system provided in the above embodiments can meet the full-load operation of a single cycle unit when the load demand is above 50%, thereby improving its operating economy. When the load demand is below 50%, it can not only achieve the hot standby state of the cycle unit in the shutdown state through internal energy, thereby improving its subsequent start-up speed, but also enable the cycle unit in the operating state to operate closer to the rated load, thereby improving the operating economy and load regulation response rate of the dual-cycle steam turbine system.
[0044] Furthermore, in the dual-cycle steam turbine system provided in this embodiment, the second cycle unit 30 includes a second high-pressure cylinder 310 and a second intermediate-pressure cylinder 320. The second high-pressure cylinder 310 and the second intermediate-pressure cylinder 320 are used to realize the staged utilization of energy during operation to improve cycle efficiency, while controlling the exhaust steam humidity to ensure the safety of the final stage.
[0045] Correspondingly, the backup steam pipe 40, used to supply superheated steam to the second circulation unit 30 when it is in hot standby mode, is branched into a first backup pipe 410 and a second backup pipe 420. The first backup pipe 410 connects to the second high-pressure cylinder 310, while the second backup pipe 420 connects to the second intermediate-pressure cylinder 320. It should be noted that, unlike in the operating state where the second intermediate-pressure cylinder 320 receives reheated steam from the second high-pressure cylinder 310, the superheated steam supply is less in the hot standby state to avoid insufficient steam supply to the first circulation unit 20, which could affect the operating load demand of the dual-cycle turbine system. Therefore, the backup steam pipe 40 adopts a more refined steam supply structure, independently supplying steam to the second high-pressure cylinder 310 and the second intermediate-pressure cylinder 320 to maintain their temperatures and keep them in a stable hot standby state. It should also be noted that regulating valves are installed on the first backup pipe 410 and the second backup pipe 420 to adjust the intake flow rate and meet independent steam supply requirements.
[0046] Based on the above embodiments, the second circulation unit 30 also includes a second low-pressure cylinder 330. It should be noted that the second intermediate-pressure cylinder 320 and the second low-pressure cylinder 330 are connected by a connecting pipe 340. The connecting pipe 340 is the pipe through which steam discharged from the second intermediate-pressure cylinder 320 reaches the second low-pressure cylinder 330 during normal operation of the second circulation unit 30. Considering the complexity of the structure and the hot standby steam pressure requirements in the second intermediate-pressure cylinder 320 and the second low-pressure cylinder 330, in this embodiment, the second low-pressure cylinder 330 is not provided with a separate hot standby pipe. Instead, the superheated steam received by the second intermediate-pressure cylinder 320 through the second standby pipe 420 reaches the second low-pressure cylinder 330 through the connecting pipe 340 after passing through the second intermediate-pressure cylinder 320, so as to maintain the hot standby state of the second low-pressure cylinder 330 and improve the superheated steam utilization efficiency.
[0047] Furthermore, the second circulation unit 30 includes a second condenser 350. Under normal operating conditions, the second condenser 350 receives steam output from each cylinder and condenses it back to the second section 120 of the boiler 10 for recycling. When the second circulation unit 30 is in hot standby mode, the loop between the second condenser 350 and the second section 120 is closed by a regulating valve, and the second high-pressure cylinder 310 is connected to the second condenser 350 via a vacuum pipe 360. The connecting pipe 340 between the second high-pressure cylinder 310 and the second condenser 350 is in the same position. The sample is equipped with a regulating valve. The superheated steam supplied by the first backup pipe 410 passes through the second high-pressure cylinder 310 to maintain the hot standby state of the second high-pressure cylinder 310 before reaching the second condenser 350 to achieve condensation. The superheated steam supplied by the other branch, namely the second backup pipe 420, will flow out from the steam outlet of the second low-pressure cylinder 330. Therefore, the steam outlet of the second low-pressure cylinder 330 is also connected to the second condenser 350, so that the superheated steam supplied by the first circulation unit 20 can reach the position of the second condenser 350 after acting on the cylinder in the second circulation unit 30 to achieve condensation and reflux.
[0048] It should be noted that, since the steam flowing out of the second high-pressure cylinder 310 will be further utilized after passing through the reheat structure when the second circulation unit 30 is in operation, the above embodiment provides an independent vacuum pipe 360 for the second high-pressure cylinder 310 to realize the connection between the hot standby steam and the second condenser 350.
[0049] It should be further explained that in some embodiments, the second condenser 350 is directly installed on the backup return water pipe 50 so that the condensate can directly reach the backup return water pipe 50. At the same time, the backup return water pipe 50 is equipped with an auxiliary condensate pump 510 with the drive direction facing the first circulation unit 20. After the condensate reaches the first circulation unit 20, it can smoothly circulate to the first section 110 position in the operating state, thereby realizing the steam return circulation of the first circulation unit 20.
[0050] Corresponding to the second circulation unit 30, in the dual-cycle steam turbine system provided in this embodiment, the first circulation unit 20 includes a first high-pressure cylinder 210 and a first intermediate-pressure cylinder 220. The first branch 110 is connected to the first high-pressure cylinder 210 through a first steam pipe to provide superheated steam to the first high-pressure cylinder 210. The first high-pressure cylinder 210 and the first intermediate-pressure cylinder 220 are connected through a reheat steam pipe 240. It should be noted that a reheater is provided on the path of the reheat steam pipe 240 to reheat the steam flowing out of the first high-pressure cylinder 210. The first intermediate-pressure cylinder 220 can accept the reheated high-temperature intermediate-pressure steam and continue to expand and do work. Through the two-stage expansion of high pressure, reheat, and intermediate pressure, the exhaust steam humidity of the single-stage steam turbine is not too high, and the average heat absorption temperature is increased, thereby improving the overall thermal efficiency of the machine. It should also be noted that the reheater on the reheat steam pipeline 240 can be set up independently, and it can also achieve steam reheating through the first section 110.
[0051] Furthermore, based on the above embodiments, the first circulation unit 20 also includes a first low-pressure cylinder 230, a first medium-pressure cylinder 220 and a first low-pressure cylinder 230 connected by a low-pressure steam pipe 250, and the steam flowing out of the first medium-pressure cylinder 220 continues to do work in the first low-pressure cylinder 230 to improve the overall operating efficiency of the machine.
[0052] Correspondingly, the first low-pressure cylinder 230 is connected to the first section 110 through the condensation pipe 270 provided with the first condenser 260, while the spare return water pipe 50 provided with the second circulation unit 30 is connected to the position of the first condenser 260 or the position of the condensation pipe 270, so as to return to the first section 110 along with the condensate in the first circulation unit 20 to achieve circulation.
[0053] It should be noted that the first circulation unit 20 can drive the condensate by setting a pump structure in the condensate pipe 270. At the same time, a low-pressure heater 2710, a deaerator 2720 and a high-pressure heater 2730 are also set in the condensate pipe 270 to process the condensate in stages before returning it to the first section 110 to complete the circulation.
[0054] Furthermore, in the dual-cycle steam turbine system provided in this embodiment, the expansion reference point 60 of the rotor component and stator component of the dual-cycle steam turbine system is set on the line of symmetry between the first high-pressure cylinder 210 and the second high-pressure cylinder 310, that is, the distance between the first high-pressure cylinder 210 and the second high-pressure cylinder 310 and the expansion reference point 60 is equal, and the rotor component expands towards both ends with respect to the expansion reference point 60, while the first high-pressure cylinder 210 and the second high-pressure cylinder 310 expand in the direction away from the expansion reference point 60, so that the expansion displacement on both sides of the dual-cycle steam turbine system is uniform during operation, improving the uniformity of axial expansion difference during steam turbine operation, and thus improving the operational stability of the dual-cycle steam turbine system.
[0055] Furthermore, it should be noted that in the first circulation unit 20, the first high-pressure cylinder 210 and the first intermediate-pressure cylinder 220 can be configured as a combined cylinder module to save space; or they can be configured as two independent modules to have a more precise and independent adjustment structure. The appropriate structural setting can be selected according to the actual operating conditions.
[0056] Furthermore, this disclosure also provides an adjustment method for adjusting the dual-cycle steam turbine system provided in any of the above embodiments. Specifically, the adjustment method can adjust the operating state of the dual-cycle steam turbine system under different load demands.
[0057] Specifically, the regulation method has high-load regulation and low-load regulation modes. When the operating load demand of the dual-cycle steam turbine system is 50% or above, it is in high-load regulation mode. At this time, the first section 110 and the first circulation unit 20 are regulated to operate at full power under rated steam parameters, so as to maintain their optimal operating state and improve the operating economy of the first section 110 and the first circulation unit 20.
[0058] Meanwhile, the second section 120 and the second circulation unit 30 are simultaneously in the start-up state, and their operation supplements the operating load difference between the dual-cycle steam turbine system and the 50% operating load, so that the dual-cycle steam turbine system meets the load demand. By maintaining the optimal operating state of the first circulation unit 20, it improves the overall economy of the dual-cycle steam turbine system.
[0059] When the operating load demand of the dual-cycle steam turbine system is below 50%, it is in a low-load regulation mode. At this time, the first regulating section 110 and the first circulation unit 20 of the dual-cycle steam turbine system are in the starting state to meet the overall load demand through the first regulating section 110 and the first circulation unit 20. It should be noted that, unlike the single-cycle system, since the maximum steam flow rate of the first regulating section 110 and the first circulation unit 20 is only half of the maximum load parameter of the dual-cycle steam turbine system, it has higher operating efficiency. For example, if the load demand of the dual-cycle steam turbine system is 40%, the single-cycle system can only operate at 40% of the maximum load operating parameter. However, in this embodiment, when the first regulating section 110 and the first circulation unit 20 meet the 40% load demand of the whole machine, their operating parameters are 80% of the maximum load operating parameters, which can improve their own operating efficiency and the cycle efficiency of the steam turbine.
[0060] Meanwhile, in low-load regulation mode, the second section 120 and the second circulation unit 30 are in hot standby mode, so that when the load demand of the dual-cycle steam turbine system is above 50%, the second section 120 and the second circulation unit 30 can be hot-started to improve the load response rate of the dual-cycle steam turbine system.
[0061] Furthermore, it should be noted that in the above-mentioned regulation method, under high-load regulation operation, the first circulation unit 20 of the dual-cycle steam turbine system operates at maximum load, without the need for adjustment of operating parameters. The load demand of the dual-cycle steam turbine system is met by the state changes of the second circulation unit 30. The regulation of the second circulation unit 30 can be achieved using either a constant-pressure throttling mode or a sliding-pressure regulation mode. In the constant-pressure throttling mode, the pressure and temperature of the main steam remain constant, while the steam flow into the turbine is controlled by changing the opening of the regulating valve, thus achieving load regulation. This mode has a relatively fast response speed. In the sliding-pressure regulation mode, the regulating valve remains fully open or at a fixed opening, and the main steam pressure is adjusted by the boiler 10 to change the steam flow and enthalpy drop, thereby achieving load regulation. This mode has smaller throttling losses but a slower response speed. In actual operation, the appropriate regulation mode can be selected based on the response speed and throttling loss requirements.
[0062] Furthermore, this disclosure also provides a thermal system including the dual-cycle steam turbine system provided in any of the above embodiments. It should be noted that since the dual-cycle steam turbine system has the technical effects provided in any of the above embodiments, the thermal system also has the technical effects provided in any of the above embodiments, and will not be repeated here.
[0063] The terms "first," "second," "left side," and "right side," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units may not be defined in the listed steps or units, but may include steps or units not listed.
[0064] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A dual-cycle steam turbine system, characterized in that, include: The boiler comprises a first section and a second section with independent circulation; The first circulation unit and the second circulation unit are symmetrically arranged about the boiler. The first circulation unit is cyclically connected to the first branch, and the second circulation unit is cyclically connected to the second branch. A backup steam pipe and a backup return water pipe are connected between the first circulation unit and the second circulation unit. The second circulation unit can receive part of the steam separated from the first circulation unit through the backup steam pipe to be in a hot standby state, and return the condensate to the first circulation unit through the backup return water pipe.
2. The dual-cycle steam turbine system as described in claim 1, characterized in that, The second circulation unit includes a second high-pressure cylinder and a second medium-pressure cylinder. The backup steam pipeline branches into a first backup pipe and a second backup pipe. The first backup pipe is connected to the second high-pressure cylinder, and the second backup pipe is connected to the second medium-pressure cylinder.
3. The dual-cycle steam turbine system as described in claim 2, characterized in that, The second circulation unit also includes a second low-pressure cylinder, and the second medium-pressure cylinder and the second low-pressure cylinder are connected by a connecting pipe through which steam is supplied.
4. The dual-cycle steam turbine system as described in claim 3, characterized in that, The second circulation unit includes a second condenser, the second high-pressure cylinder is connected to the second condenser through a vacuum pipe, and the steam outlet of the second low-pressure cylinder is directly connected to the second condenser.
5. The dual-cycle steam turbine system as described in claim 4, characterized in that, The second condenser is installed on the backup return water pipe, and the backup return water pipe is equipped with an auxiliary condensate pump whose driving direction is toward the first circulation unit.
6. The dual-cycle steam turbine system as described in claim 2, characterized in that, The first circulation unit includes a first high-pressure cylinder and a first medium-pressure cylinder. The first part is connected to the first high-pressure cylinder through a first steam pipe. The first high-pressure cylinder and the first medium-pressure cylinder are connected through a reheat steam pipe, and a reheater is provided along the path of the reheat steam pipe.
7. The dual-cycle steam turbine system as described in claim 6, characterized in that, The first circulation unit further includes a first low-pressure cylinder, the first medium-pressure cylinder and the first low-pressure cylinder are connected by a low-pressure steam pipeline, and the first low-pressure cylinder is connected to the first section by a condensing pipeline equipped with a first condenser; the spare return water pipeline is connected to the first condenser or the condensing pipeline.
8. The dual-cycle steam turbine system as described in claim 6, characterized in that, The expansion reference points of the rotor and stator components of the dual-cycle steam turbine system are set on the line of symmetry between the first high-pressure cylinder and the second high-pressure cylinder. The rotor component expands towards both ends with respect to the expansion reference points, and both the first high-pressure cylinder and the second high-pressure cylinder expand in a direction away from the expansion reference points.
9. The dual-cycle steam turbine system as described in claim 6, characterized in that, The first high-pressure cylinder and the first intermediate-pressure cylinder are either a combined cylinder module or two independently configured modules.
10. An adjustment method, characterized in that, The method for regulating the dual-cycle steam turbine system as described in any one of claims 1-9 includes: High load regulation: When the operating load demand of the dual-cycle steam turbine system is 50% or above, the first section and the first circulation unit are regulated to operate at full power under rated steam parameters, and the second section and the second circulation unit are started synchronously and operated at a power not greater than that under rated steam parameters; Low load adjustment: When the operating load demand of the dual-cycle steam turbine system is below 50%, the first section and the first cycle unit are adjusted to operate at the power required by the whole machine's operating load, while the second section and the second cycle unit are in the hot standby state.
11. The adjustment method as described in claim 10, characterized in that, When the dual-cycle steam turbine system is in high-load regulation operation, the second cycle unit operates in constant pressure throttling mode or sliding pressure regulation mode.
12. A thermal system, characterized in that, Includes the dual-cycle steam turbine system as described in any one of claims 1-9.