A compound dynamic steam distribution wide-range coordinated steam turbine system and operation method

Abstract

The application discloses a kind of compound dynamic steam distribution wide-range cooperation steam turbine system and operating method, comprising: boiler and coaxial arrangement and sequentially connected first high-pressure cylinder, second high-pressure cylinder, middle-pressure cylinder, low-pressure cylinder and generator;The boiler is connected with main steam pipeline and reheat steam cold section pipeline;The steam inlet of first high-pressure cylinder and second high-pressure cylinder is communicated with main steam pipeline respectively;The exhaust side of first high-pressure cylinder and second high-pressure cylinder is communicated with reheat steam cold section pipeline respectively;Boiler is connected with middle-pressure cylinder by reheat steam hot section pipeline, and middle-pressure cylinder is connected with low-pressure cylinder by middle-low pressure communication pipe;Second high-pressure cylinder is connected with regenerative system by multiple second high-pressure cylinder steam extraction pipeline;The pipeline that the exhaust side of first high-pressure cylinder is connected with reheat steam cold section pipeline is equipped with the first high-pressure cylinder steam extraction pipeline that is communicated with deaerator.The application has the advantages of full-range fast flexible adjustment, wide-load efficient operation, can reduce operating cost and improve economy.

Description

Technical Field

[0001] This invention belongs to the field of steam turbine power generation, specifically a composite dynamic steam distribution wide-range coordinated steam turbine system and its operation method. Background Technology

[0002] With the increasing generation of renewable energy sources such as wind and solar power, which are characterized by intermittency and instability, while the curtailment of wind and solar power remains high, the power grid is placing increasingly higher demands on the flexible operation and wide-load performance of coal-fired power units. Currently, the low-load economic efficiency of coal-fired power units has decreased significantly. Due to the limitations of the regenerative section of the turbine system, the unit's load change rate is also slow, resulting in high operating costs and low economic returns, making it unable to meet the operational requirements of new coal-fired power units.

[0003] To address the above problems, this invention proposes a composite dynamic steam distribution wide-range coordinated steam turbine system and its operation method, which improves the unit's response speed under changing loads and its economy under wide loads, enabling coal-fired power units to achieve rapid and flexible adjustment across the entire range and efficient operation under wide loads, bringing considerable economic and social benefits to power plants. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a composite dynamic steam distribution wide-range coordinated steam turbine system and its operation method, which features rapid and flexible adjustment across the entire range, high efficiency under wide loads, reduced operating costs, and increased profitability.

[0005] The technical objective of this invention is achieved through the following technical solution:

[0006] A composite dynamic steam distribution wide-range coordinated steam turbine system includes: a boiler and a first high-pressure cylinder, a second high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, and a generator arranged coaxially and connected sequentially; the boiler is connected to a main steam pipeline and a reheat steam cold section pipeline; the steam inlets of the first and second high-pressure cylinders are respectively connected to the main steam pipeline; the exhaust sides of the first and second high-pressure cylinders are respectively connected to the reheat steam cold section pipeline; the boiler is connected to the intermediate-pressure cylinder through the reheat steam hot section pipeline, and the intermediate-pressure cylinder and the low-pressure cylinder are connected by an intermediate-low pressure connecting pipe; the second high-pressure cylinder is connected to a regenerative system through multiple second high-pressure cylinder extraction steam pipelines; the pipeline connecting the exhaust side of the first high-pressure cylinder to the reheat steam cold section pipeline is provided with a first high-pressure cylinder extraction steam pipeline connected to a deaerator.

[0007] Preferably, the main steam pipeline includes a main steam pipeline header connected to the boiler; two main steam pipeline branches are connected in parallel on the side of the main steam pipeline header away from the boiler, and are respectively connected to the steam inlets of the first high-pressure cylinder and the second high-pressure cylinder; each of the two main steam pipeline branches is provided with a steam inlet regulating valve for adjusting the steam flow.

[0008] Preferably, the reheat steam cold section pipeline includes a reheat steam cold section pipeline main pipe connected to the boiler; the reheat steam cold section pipeline main pipe is connected in parallel to a first reheat steam cold section pipeline branch and a second reheat steam cold section pipeline branch on the side away from the boiler; one end of the first reheat steam cold section pipeline branch is connected to the reheat steam cold section pipeline main pipe, and the other end is connected to the first high-pressure cylinder exhaust port on the exhaust side of the first high-pressure cylinder; one end of the second reheat steam cold section pipeline branch is connected to the reheat steam cold section pipeline main pipe, and the other end is connected to the second high-pressure cylinder exhaust port.

[0009] Preferably, the first reheat steam cold section pipeline branch is provided with a first high-pressure cylinder extraction pipeline and a first exhaust regulating valve; the steam inlet of the first high-pressure cylinder extraction pipeline is connected to the first reheat steam cold section pipeline branch between the first high-pressure cylinder exhaust port and the first exhaust regulating valve, and its exhaust end is connected to the deaerator;

[0010] A second exhaust regulating valve is installed on the extraction steam pipeline of the first high-pressure cylinder.

[0011] Preferably, the second high-pressure cylinder extraction steam pipeline includes a first high-pressure cylinder extraction steam pipeline, a second high-pressure cylinder extraction steam pipeline, and a third high-pressure cylinder extraction steam pipeline, which are respectively connected to the first extraction steam port, the second extraction steam port, and the exhaust steam port of the second high-pressure cylinder; the first high-pressure cylinder extraction steam pipeline, the second high-pressure cylinder extraction steam pipeline, and the third high-pressure cylinder extraction steam pipeline are respectively connected to the regenerative system; one end of the branch of the second reheat steam cold section pipeline is connected to the main pipe of the reheat steam cold section pipeline, and the other end is connected to the third high-pressure cylinder extraction steam pipeline of the second high-pressure cylinder.

[0012] Preferably, the design steam inlet flow rate of the first high-pressure cylinder is 25% to 50% of the rated main steam flow rate of the unit; and the design steam inlet flow rate of the second high-pressure cylinder is 50% to 75% of the rated main steam flow rate of the unit.

[0013] Preferably, the steam inlet regulating valve includes a first high-pressure cylinder steam inlet regulating valve and a second high-pressure cylinder steam inlet regulating valve; the first high-pressure cylinder steam inlet regulating valve is located on the first main steam pipeline branch from the main steam pipeline header to the first high-pressure cylinder; the second high-pressure cylinder steam inlet regulating valve is located on the second main steam pipeline branch from the main steam pipeline header to the second high-pressure cylinder.

[0014] An operation method for the aforementioned composite dynamic steam distribution wide-range coordinated steam turbine system.

[0015] When the unit load is higher than the load switching point:

[0016] The unit operates under sliding pressure, with main steam entering the first high-pressure cylinder and the second high-pressure cylinder respectively. The steam inlet regulating valve of the second high-pressure cylinder remains fully open, with no valve throttling loss. The opening of the steam inlet regulating valve of the first high-pressure cylinder decreases as the unit load decreases.

[0017] When the unit load decreases towards the load switching point:

[0018] The second high-pressure cylinder inlet steam regulating valve remains fully open, while the opening of the first high-pressure cylinder inlet steam regulating valve gradually decreases to reduce the main steam flow into the first high-pressure cylinder. At this time, the first exhaust steam regulating valve remains open, and the second exhaust steam regulating valve remains closed.

[0019] When the unit load drops to the load switching point:

[0020] The opening of the steam inlet regulating valve of the first high-pressure cylinder is reduced to the minimum design opening. Only a certain amount of cooling steam is introduced into the first high-pressure cylinder, keeping it in a hot standby state to prevent the unit from overheating during idling. At this time, the first exhaust regulating valve is closed and the second exhaust regulating valve is opened, switching the exhaust steam from the reheat steam cold section pipeline to the deaerator. Compared with exhausting steam to the condenser, the back pressure is higher and the required steam flow is smaller, resulting in less impact on the unit's economy. The steam inlet regulating valve of the second high-pressure cylinder remains fully open.

[0021] When the unit load is lower than the load switching point:

[0022] The unit starts sliding pressure operation from the rated main steam pressure. A small amount of steam is introduced into the first high-pressure cylinder to maintain the hot standby state. The first exhaust steam regulating valve is kept closed, and the second exhaust steam regulating valve is kept open. The exhaust steam from the first high-pressure cylinder is sent to the deaerator. The steam inlet regulating valve of the second high-pressure cylinder is kept fully open, and the second high-pressure cylinder operates in sliding pressure mode.

[0023] Preferably, the load switching point is less than or equal to the upper limit of the design load ratio of the second high-pressure cylinder.

[0024] Preferably, the flow distribution ratio of the first high-pressure cylinder and the second high-pressure cylinder depends on the expected operating load distribution ratio of the unit and is determined based on the optimal weighted heat consumption benefit.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. The composite dynamic steam distribution wide-range coordinated steam turbine system of the present invention replaces the traditional single high-pressure cylinder with a double high-pressure cylinder arranged coaxially in parallel with steam of a certain flow ratio. Compared with the two high-pressure cylinders arranged on separate shafts, this layout does not require the addition of a motor, thus reducing investment costs. At the same time, the second high-pressure cylinder is equipped with a partial regeneration system, while the first high-pressure cylinder is not equipped with a regeneration system. This layout improves the system load adjustment flexibility and low-load operating cycle efficiency.

[0027] When the unit load decreases to the switching point, the exhaust steam from the first high-pressure cylinder switches to the deaerator, and cooling steam is introduced to maintain hot standby status. When load demand increases, the first high-pressure cylinder can be quickly put into operation, significantly improving the unit's response speed to load changes and meeting the rapid adjustment requirements of the power system. The first high-pressure cylinder does not have a regenerator, allowing it to quickly switch to hot standby after the load drops to the switching point, further enhancing operational flexibility.

[0028] When the unit load is below the load switching point, except for a small amount of steam to maintain the hot standby of the first high-pressure cylinder, all the main steam flows into the second high-pressure cylinder. The second high-pressure cylinder operates under sliding pressure, and its pressure is higher than that of the conventional unit under the same load during "constant-sliding-constant" operation. Moreover, the second high-pressure cylinder is always in the condition of fully open high-efficiency valves, which reduces valve throttling losses and effectively improves the economy of the unit under low load. The lower the load, the higher the economic benefits of this system.

[0029] This invention can maintain efficient operation under different load conditions, meet the power system's requirements for flexibility and economy, realize rapid and flexible adjustment across the entire range and efficient operation under wide load, and effectively reduce operating costs and improve economy.

[0030] 2. The operating method of the composite dynamic steam distribution wide-range coordinated steam turbine system of the present invention can flexibly adjust the unit load between the load switching point and the load distribution point, which can meet the requirements of rapid load change and wide-load high efficiency of the new generation of coal-fired power units, realize the rapid and flexible adjustment of the coal-fired power unit across the entire range and the high-efficiency operation under wide load, and bring considerable economic and social benefits to power plants in the spot market and ancillary service market. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the present invention;

[0032] Figure reference numerals: 1—boiler; 11—reheat steam hot section piping;

[0033] 2—First high-pressure cylinder; 21—First high-pressure cylinder inlet steam regulating valve; 22—First exhaust steam regulating valve; 23—First high-pressure cylinder extraction steam pipeline; 24—Second exhaust steam regulating valve;

[0034] 3—Second high-pressure cylinder; 31—Second high-pressure cylinder inlet steam regulating valve; 32—Second high-pressure cylinder third extraction steam pipeline; 33—Second high-pressure cylinder second extraction steam pipeline; 34—Second high-pressure cylinder first extraction steam pipeline;

[0035] 4—Intermediate pressure cylinder;

[0036] 5—Low-pressure cylinder;

[0037] 6—Generator;

[0038] 71—Main steam pipeline; 72—First main steam pipeline branch; 73—Second main steam pipeline branch;

[0039] 81—Main pipe of reheat steam cold section; 82—Branch of first reheat steam cold section; 83—Branch of second reheat steam cold section;

[0040] 9—Medium and low voltage connecting pipe. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0043] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. Example 1

[0044] like Figure 1 As shown, a composite dynamic steam distribution wide-range coordinated steam turbine system includes: a boiler 1 and a first high-pressure cylinder 2, a second high-pressure cylinder 3, an intermediate-pressure cylinder 4, a low-pressure cylinder 5, and a generator 6 arranged coaxially and connected in sequence; the boiler 1 is connected to a main steam pipeline and a reheat steam cold section pipeline; the steam inlets of the first high-pressure cylinder 2 and the second high-pressure cylinder 3 are respectively connected to the main steam pipeline; the exhaust sides of the first high-pressure cylinder 2 and the second high-pressure cylinder 3 are respectively connected to the reheat steam cold section pipeline; the boiler 1 is connected to the intermediate-pressure cylinder 4 through the reheat steam hot section pipeline 11, and the intermediate-pressure cylinder 4 and the low-pressure cylinder 5 are connected by an intermediate-low pressure connecting pipe 9; the second high-pressure cylinder 3 is connected to the regenerative system through multiple second high-pressure cylinder extraction steam pipelines; the first high-pressure cylinder extraction steam pipeline 23, which connects to the deaerator, is provided on the pipeline connecting the exhaust side of the first high-pressure cylinder 2 to the reheat steam cold section pipeline.

[0045] In practical use, the traditional single high-pressure cylinder is replaced with a double high-pressure cylinder arranged coaxially in parallel with steam of a certain flow ratio. Compared with the two high-pressure cylinders arranged on separate shafts, this layout eliminates the need for an additional motor, reducing investment costs. At the same time, the second high-pressure cylinder 3 is equipped with a partial regeneration system, while the first high-pressure cylinder 2 is not. This layout improves the system load adjustment flexibility and low-load operating efficiency, allowing the second high-pressure cylinder 3 to always operate at rated load, while the first high-pressure cylinder 2 can flexibly adjust to partial load operation, thus optimizing overall performance.

[0046] When the unit load decreases to the switching point, the exhaust steam from the first high-pressure cylinder 2 is switched to the deaerator, and cooling steam is introduced to maintain a hot standby state. When load demand increases, the first high-pressure cylinder 2 can be quickly put into operation, significantly improving the unit's response speed to load changes and meeting the rapid adjustment requirements of the power system. The first high-pressure cylinder 2 does not have a regenerator, which allows it to quickly switch to hot standby after the load drops to the switching point, further enhancing operational flexibility.

[0047] When the unit load is below the load switching point, all main steam flows into the second high-pressure cylinder 3, except for a small amount of steam used to maintain the hot standby of the first high-pressure cylinder 2. The second high-pressure cylinder 3 operates under sliding pressure, with a pressure higher than that of a conventional unit operating under "stationary-sliding-stationary" conditions. Furthermore, the second high-pressure cylinder is always in a fully open, high-efficiency valve operation condition, reducing valve throttling losses and effectively improving the economic efficiency of the unit under low load. The lower the load, the higher the economic benefits of this system. This system can maintain efficient operation under different load conditions, meeting the power system's requirements for flexibility and economy. It achieves rapid and flexible regulation across the entire range and efficient operation under wide loads, reducing operating costs and improving economic efficiency.

[0048] like Figure 1 As shown, boiler 1 is connected to the steam inlets of the first high-pressure cylinder 2 and the second high-pressure cylinder 3 via a main steam pipeline. In a specific implementation, the main steam pipeline includes a main steam pipeline header 71 connected to boiler 1; two main steam pipeline branches are connected in parallel on the side of the main steam pipeline header 71 away from boiler 1, and are respectively connected to the steam inlets of the first high-pressure cylinder 2 and the second high-pressure cylinder 3; each of the two main steam pipeline branches is equipped with a steam inlet regulating valve for adjusting the steam flow rate.

[0049] The steam inlet regulating valve includes a first high-pressure cylinder steam inlet regulating valve 21 and a second high-pressure cylinder steam inlet regulating valve 31. The first high-pressure cylinder steam inlet regulating valve 21 is installed on the first main steam pipeline branch 72 from the main steam pipeline header 71 to the first high-pressure cylinder 2. The second high-pressure cylinder steam inlet regulating valve 31 is installed on the second main steam pipeline branch 73 from the main steam pipeline header 71 to the second high-pressure cylinder 3.

[0050] In practical use, the steam supply of each branch of the main steam pipeline and the inlet steam regulating valve can be precisely controlled to meet the different flow matching requirements under different operating loads, making the system more efficient. When the first high-pressure cylinder 2 needs to be switched to hot standby, its steam intake can be reduced by adjusting the inlet steam regulating valve 21, the first exhaust regulating valve is closed, and the second exhaust regulating valve is opened, so that the exhaust of the first high-pressure cylinder is switched to the deaerator, while ensuring the normal operation of the second high-pressure cylinder 3, ensuring the flexibility and stability of the overall unit operation. Compared with the design of a single high-pressure cylinder, this layout does not require complex internal structural modifications, only two branches are connected in parallel on the main steam pipeline header 71 and valves are installed on each branch. This effectively simplifies the system structure and reduces the difficulty of operation and control. Therefore, by optimizing flow distribution, precise regulation, and flexible operation, the adoption of this system structure significantly improves the turbine unit's overall flexible regulation capability and wide-load economy.

[0051] like Figure 1 As shown, the reheat steam cold section pipeline includes a main reheat steam cold section pipeline 81 connected to boiler 1; the side of the main reheat steam cold section pipeline 81 away from boiler 1 is connected in parallel to a first reheat steam cold section pipeline branch 82 and a second reheat steam cold section pipeline branch 83; one end of the first reheat steam cold section pipeline branch 82 is connected to the main reheat steam cold section pipeline 81, and the other end is connected to the exhaust port of the first high-pressure cylinder 2 on the exhaust side; one end of the second reheat steam cold section pipeline branch 83 is connected to the main reheat steam cold section pipeline 81, and the other end is connected to the exhaust port of the second high-pressure cylinder 3. In actual use, the steam discharged from the two high-pressure cylinders is concentrated and transported back to boiler 1 for reheating by connecting the main reheat steam cold section pipeline 81 to the exhaust side of the first high-pressure cylinder 2 and the second high-pressure cylinder 3. By employing parallel first reheat steam cold section pipe branch 82 and second reheat steam cold section pipe branch 83, the exhaust steam of the two high-pressure cylinders can be effectively controlled and managed separately. The exhaust steam flow direction and flow rate can be flexibly adjusted according to different operating conditions, optimizing system operation. Connecting the second reheat steam cold section pipe branch 83 to the extraction steam pipe of the second high-pressure cylinder 3 allows a portion of the exhaust steam from the second high-pressure cylinder 3 to be introduced into the regenerative system, achieving cascaded utilization of thermal energy and improving thermal economy. This design better adapts to the operating requirements under different load conditions, improving the operational flexibility and adaptability of the turbine system, enabling it to maintain efficient thermal energy utilization and stable operation under various conditions.

[0052] In practical implementation, the first reheat steam cold section pipeline branch 82 is equipped with a first high-pressure cylinder extraction steam pipeline 23 and a first exhaust steam regulating valve 22. The steam inlet of the first high-pressure cylinder extraction steam pipeline 23 is connected to the first reheat steam cold section pipeline branch 82 between the exhaust port of the first high-pressure cylinder 2 and the first exhaust steam regulating valve 22, and its exhaust end is connected to the deaerator (not shown in the figure). The first high-pressure cylinder extraction steam pipeline 23 is equipped with a second exhaust steam regulating valve 24. In actual use, by setting the first reheat steam cold section pipeline branch 82, the first high-pressure cylinder extraction steam pipeline 23, the first exhaust steam regulating valve 22, and the second exhaust steam regulating valve 24, the exhaust steam flow direction of the first high-pressure cylinder 2 can be flexibly adjusted according to the changes in unit load. When the unit load decreases, by opening or closing the corresponding exhaust steam regulating valve, the exhaust steam of the first high-pressure cylinder 2 can be switched to the deaerator, allowing the first high-pressure cylinder 2 to quickly enter hot standby mode. When the unit load is below the switching point, the second high-pressure cylinder 3 continues to operate at full capacity and slide pressure, while the first high-pressure cylinder remains in hot standby mode, ensuring stable unit operation and rapid response to load changes. The exhaust steam from the first high-pressure cylinder 2 is switched to the deaerator via the first high-pressure cylinder extraction pipe 23 to heat the water in the deaerator, improving thermal energy utilization efficiency, reducing energy waste, and enhancing system economy. By optimizing load regulation and thermal energy utilization, the unit's operating costs are reduced, improving overall economic efficiency and market competitiveness.

[0053] In practical implementation, the second high-pressure cylinder extraction pipeline of the second high-pressure cylinder 3 includes a first high-pressure cylinder extraction pipeline 34, a second high-pressure cylinder extraction pipeline 33, and a third high-pressure cylinder extraction pipeline 32, which are respectively connected to the first extraction port, the second extraction port, and the exhaust port of the second high-pressure cylinder 3. The third high-pressure cylinder extraction pipeline 32, the second high-pressure cylinder extraction pipeline 33, and the first high-pressure cylinder extraction pipeline 34 are respectively connected to the reheat system. One end of the branch pipeline 83 of the second reheat steam cold section is connected to the main pipeline 81 of the reheat steam cold section, and the other end is connected to the third high-pressure cylinder extraction pipeline 32 of the second high-pressure cylinder 3. In actual use, the reheat system is equipped with a first high-pressure heater, a second high-pressure heater, and a third high-pressure heater corresponding to the third high-pressure cylinder extraction pipeline 32, the second high-pressure cylinder extraction pipeline 33, and the third high-pressure cylinder extraction pipeline 34.

[0054] In specific implementation, the design steam inlet flow rate of the first high-pressure cylinder 2 is 25% to 50% of the rated main steam flow rate of the unit; the design steam inlet flow rate of the second high-pressure cylinder 3 is 50% to 75% of the rated main steam flow rate of the unit. Example 2

[0055] An operation method for a steam turbine system with composite dynamic steam distribution wide-range coordination in Embodiment 1 is as follows:

[0056] When the unit load is higher than the load switching point:

[0057] The unit operates under sliding pressure, with main steam entering the first high-pressure cylinder 2 and the second high-pressure cylinder 3 respectively. The steam inlet regulating valve 31 of the second high-pressure cylinder remains fully open, with no valve throttling loss. The opening of the steam inlet regulating valve 21 of the first high-pressure cylinder decreases as the unit load decreases.

[0058] When the unit load decreases towards the load switching point:

[0059] The second high-pressure cylinder inlet steam regulating valve 31 remains fully open, while the opening of the first high-pressure cylinder inlet steam regulating valve 21 gradually decreases to reduce the main steam flow into the first high-pressure cylinder 2. At this time, the first exhaust steam regulating valve 22 remains open, and the second exhaust steam regulating valve 24 remains closed.

[0060] When the unit load drops to the load switching point:

[0061] The opening of the first high-pressure cylinder inlet steam regulating valve 21 is reduced to the design minimum opening, and only a certain amount of cooling steam is introduced into the first high-pressure cylinder 2, so that the first high-pressure cylinder 2 is in a hot standby state, avoiding overheating of the blower during unit idling; at this time, the first exhaust steam regulating valve 22 is closed and the second exhaust steam regulating valve 24 is opened, so that the exhaust steam of the first high-pressure cylinder 2 is switched from the reheat steam cold section pipeline to the deaerator, so as to introduce a small amount of steam to maintain the hot standby state of the first high-pressure cylinder 2, which has little impact on the unit's economy, and can be quickly put into operation when the unit needs to increase load again; the second high-pressure cylinder inlet steam regulating valve 31 remains fully open; since the first high-pressure cylinder 2 is cut off, the flow area is reduced, the main steam pressure is increased to the rated value, the unit's cycle efficiency is greatly improved, and thus the unit's economy is improved.

[0062] When the unit load is lower than the load switching point:

[0063] The unit starts sliding pressure operation from the rated main steam pressure. A small amount of steam is introduced into the first high-pressure cylinder 2 to maintain the hot standby state. The first exhaust steam regulating valve 22 is kept closed, and the second exhaust steam regulating valve 24 is kept open. The exhaust steam of the first high-pressure cylinder 2 is sent to the deaerator. The second high-pressure cylinder inlet steam regulating valve 31 is kept fully open, and the second high-pressure cylinder 3 operates under sliding pressure. The overall sliding pressure main steam pressure is higher than that of the conventional system at the same load, so the cycle efficiency is also higher. That is, the economic efficiency of the unit is significantly improved compared with the conventional system when operating below the load switching point.

[0064] In actual operation, the load switching point is less than or equal to the upper limit of the design load ratio of the second high-pressure cylinder 3.

[0065] For example, the design steam inlet flow rate of the first high-pressure cylinder 2 is 25% of the rated main steam flow rate of the unit; the design steam inlet flow rate of the second high-pressure cylinder 3 is 75% of the rated main steam flow rate of the unit. Load is usually proportional to steam flow rate. Therefore, the design steam inlet flow rate percentage can be considered as the design load percentage. In this case, the upper limit of the design load percentage of the second high-pressure cylinder is approximately 75% (the second high-pressure cylinder includes some regenerative extraction steam, so the actual percentage is slightly less than 75%).

[0066] In practice, the flow distribution ratio of the first high-pressure cylinder 2 and the second high-pressure cylinder 3 depends on the expected operating load distribution ratio of the unit and is determined based on the optimal weighted heat consumption benefit.

[0067] For example, the design steam inlet flow rate of the first high-pressure cylinder is Q1, and the design steam inlet flow rate of the second high-pressure cylinder is Q2. When the proportion of low-load (50% and below load) operation of the unit is very high, the design of Q1:Q2=5:5 can be adopted. When the proportion of high-load (50%-75% load) operation of the unit is also high, the design of Q1:Q2=7:3 can be adopted.

[0068] The technical solutions provided by the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of the present invention. The descriptions of the embodiments above are only for helping to understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A compound dynamic steam distribution wide-range coordinated steam turbine system, characterized in that, The utility model relates to a kind of steam turbine unit, including: Boiler and coaxially arranged and sequentially connected first high-pressure cylinder, second high-pressure cylinder, medium-pressure cylinder, low-pressure cylinder and generator; The boiler is connected with main steam pipeline and reheat steam cold section pipeline; The steam inlet of the first high-pressure cylinder and the second high-pressure cylinder is communicated with main steam pipeline respectively; The exhaust side of the first high-pressure cylinder and the second high-pressure cylinder is communicated with reheat steam cold section pipeline respectively; The boiler is connected with medium-pressure cylinder by reheat steam hot section pipeline, and the medium-pressure cylinder is connected with low-pressure cylinder by medium-low pressure communication pipe; The second high-pressure cylinder is connected with regenerative system by multiple second high-pressure cylinder steam extraction pipelines; The first high-pressure cylinder exhaust side is equipped with the first high-pressure cylinder steam extraction pipeline communicated with deaerator on the pipeline connected with reheat steam cold section pipeline; The design steam flow of the first high-pressure cylinder is 25%~50% of unit rated main steam flow; The design steam flow of the second high-pressure cylinder is 50%~75% of unit rated main steam flow.

2. The compound dynamic governing wide range coordinated steam turbine system of claim 1, wherein, The main steam pipeline includes main steam pipeline main pipe connected with boiler; Two main steam pipeline branches are connected in parallel on the side of main steam pipeline main pipe away from boiler, and the steam inlet of first high-pressure cylinder and second high-pressure cylinder is connected respectively; Two main steam pipeline branches are respectively equipped with steam inlet regulating valve for adjusting steam flow.

3. The compound dynamic governing wide range coordinated steam turbine system of claim 1, wherein, The reheat steam cold section pipeline includes reheat steam cold section pipeline main pipe connected with boiler; First reheat steam cold section pipeline branch and second reheat steam cold section pipeline branch are connected in parallel on the side of reheat steam cold section pipeline main pipe away from boiler; One end of the first reheat steam cold section pipeline branch is connected with reheat steam cold section pipeline main pipe, and the other end is connected with the exhaust port of first high-pressure cylinder; One end of the second reheat steam cold section pipeline branch is connected with reheat steam cold section pipeline main pipe, and the other end is connected with the exhaust port of second high-pressure cylinder.

4. The compound dynamic governing wide range coordinated steam turbine system of claim 3, wherein, First high-pressure cylinder steam extraction pipeline and first exhaust regulating valve are equipped on the first reheat steam cold section pipeline branch; The steam inlet end of first high-pressure cylinder steam extraction pipeline is connected on the first reheat steam cold section pipeline branch between first high-pressure cylinder exhaust port and first exhaust regulating valve, and the steam outlet end is connected with deaerator; Second exhaust regulating valve is equipped on the first high-pressure cylinder steam extraction pipeline.

5. The compound dynamic governing wide range coordinated steam turbine system, according to claim 3, characterized in that, Second high-pressure cylinder steam extraction pipeline of the second high-pressure cylinder includes second high-pressure cylinder first steam extraction pipeline, second high-pressure cylinder second steam extraction pipeline and second high-pressure cylinder third steam extraction pipeline connected with first steam extraction port, second steam extraction port and exhaust port of second high-pressure cylinder respectively; Second high-pressure cylinder first steam extraction pipeline, second high-pressure cylinder second steam extraction pipeline and second high-pressure cylinder third steam extraction pipeline are connected with regenerative system respectively; The other end of the second reheat steam cold section pipeline branch is connected on the second high-pressure cylinder third steam extraction pipeline.

6. The compound dynamic governing wide range coordinated steam turbine system, according to claim 2, characterized in that, The steam inlet regulating valve includes first high-pressure cylinder steam inlet regulating valve and second high-pressure cylinder steam inlet regulating valve; The first high-pressure cylinder steam inlet regulating valve is arranged on the first main steam pipeline branch from main steam pipeline main pipe to first high-pressure cylinder; The second high-pressure cylinder steam inlet regulating valve is arranged on the second main steam pipeline branch from main steam pipeline main pipe to second high-pressure cylinder.

7. The operation method of the composite dynamic steam distribution wide-range coordinated steam turbine system according to any one of claims 1-6, characterized in that, when the unit load is higher than the load switching point: the unit is operated at sliding pressure, and the main steam enters the first high-pressure cylinder and the second high-pressure cylinder, wherein the second high-pressure cylinder admission regulating valve is kept fully open, and there is no throttling loss of the valve; the opening degree of the first high-pressure cylinder admission regulating valve decreases with the decrease of the unit load; when the unit load decreases to the load switching point: the second high-pressure cylinder admission regulating valve is kept fully open, and the opening degree of the first high-pressure cylinder admission regulating valve gradually decreases to reduce the main steam flow entering the first high-pressure cylinder; at this time, the first exhaust regulating valve is kept open, and the second exhaust regulating valve is kept closed; when the unit load decreases to the load switching point: the opening degree of the first high-pressure cylinder admission regulating valve decreases to the designed minimum opening degree, and only a certain amount of cooling steam is introduced into the first high-pressure cylinder, so that the first high-pressure cylinder is in a hot standby state; at this time, the first exhaust regulating valve is closed, the second exhaust regulating valve is opened, so that the exhaust of the first high-pressure cylinder is switched from the reheated steam cold section pipeline to the deaerator, and the second high-pressure cylinder admission regulating valve is still kept fully open; when the unit load is lower than the load switching point: the unit is operated at sliding pressure starting from the rated main steam pressure, a small amount of steam is introduced into the first high-pressure cylinder to keep the hot standby state, the first exhaust regulating valve is kept closed, the second exhaust regulating valve is kept open, and the exhaust of the first high-pressure cylinder is to the deaerator; the second high-pressure cylinder admission regulating valve is kept fully open, and the second high-pressure cylinder is operated at sliding pressure.

8. The method of operating a compound dynamic governing wide range coordinated steam turbine system of claim 7 wherein: The load switching point load ≤ the upper limit of the designed load proportion of the second high-pressure cylinder.

9. The method of operating a compound dynamic governing wide range coordinated steam turbine system of claim 8 wherein: The flow distribution selection ratio of the first high-pressure cylinder and the second high-pressure cylinder depends on the expected operation load distribution proportion of the unit, and is determined according to the optimal weighted heat consumption benefit.

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