Rapid thermal state starting system and method for thermal power generating unit

Abstract

The invention relates to a rapid thermal state starting system and method for a thermal power generating unit. The rapid thermal state starting system of the thermal power generating unit comprises a shaft seal steam system, an interlayer steam inlet header, a steam main pipe and an auxiliary steam header, the steam main pipe is used for being communicated with a boiler of the thermal power generating unit, and the steam main pipe is connected with the shaft seal steam system through a first steam supply pipeline so as to supply steam to the shaft seal steam system; the steam header is connected with the interlayer steam inlet header through a second steam supply pipeline so as to supply steam to the interlayer steam inlet header, the auxiliary steam header is connected with the shaft seal steam system through a third steam supply pipeline so as to supply steam to the shaft seal steam system, and the auxiliary steam header is connected with the interlayer steam inlet header through a fourth steam supply pipeline so as to supply steam to the interlayer steam inlet header. According to the rapid thermal state starting system of the thermal power generating unit, the time from cold state starting to grid connection of the thermal power generating unit is remarkably shortened, the heat efficiency of the starting process is improved, and the starting energy consumption and the operation cost are reduced.

Description

Technical Field

[0001] The present invention relates to the field of thermoelectric technology, and in particular to a rapid hot start system and method for a thermal power unit. Background Art

[0002] With the growth of energy demand and the improvement of environmental protection requirements, thermal power units, as an important source of electricity supply, are particularly important for efficient and energy-saving operation. However, there are many technical bottlenecks and economic problems in the cold start process of thermal power units, which makes the start process time-consuming and energy loss large, which directly affects the stable operation and economic benefits of the power system. In related technologies, thermal power units usually need to be started twice, and the time from ignition to grid-connected start is about 15 hours. After the first start, the unit trips due to large shaft vibration, and the warm-up time must be extended, which makes the entire start process take at least 21 hours, and the energy consumption and fuel costs increase significantly. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, an embodiment of the present invention proposes a rapid hot start system for a thermal power unit, which significantly shortens the time from cold start to grid connection of the thermal power unit, improves the thermal efficiency of the startup process, and reduces startup energy consumption and operating costs.

[0005] An embodiment of the present invention provides a method for rapid hot start of a thermal power unit.

[0006] According to an embodiment of the present invention, a rapid hot start system for a thermal power unit includes a shaft sealing steam system, an interlayer steam inlet header, a steam main pipe and an auxiliary steam header, wherein the steam main pipe is used to connect to the boiler of the thermal power unit, the steam main pipe is connected to the shaft sealing steam system through a first steam supply pipeline to supply steam to the shaft sealing steam system, a first valve group is provided on the first steam supply pipeline, the steam main pipe is connected to the interlayer steam inlet header through a second steam supply pipeline to supply steam to the interlayer steam inlet header, a second valve group is provided on the second steam supply pipeline, the auxiliary steam header is connected to the shaft sealing steam system through a third steam supply pipeline to supply steam to the shaft sealing steam system, a third valve group is provided on the third steam supply pipeline, the auxiliary steam header is connected to the interlayer steam inlet header through a fourth steam supply pipeline to supply steam to the interlayer steam inlet header, and a fourth valve group is provided on the fourth steam supply pipeline.

[0007] The thermal power unit rapid hot start system of the embodiment of the present invention realizes two-stage preheating by introducing an auxiliary steam header and an interlayer steam inlet header, so that the temperature inside and outside the cylinder reaches the hot start requirement before the start-up, thereby achieving a successful start-up of the unit and shortening the start-up time, and also improving the thermal energy utilization rate during the start-up process, ensuring that the cylinder metal temperature quickly approaches the hot start standard, avoiding the machine tripping and additional warm-up time caused by insufficient initial temperature, thereby reducing external energy loss during the start-up period, and further improving thermal efficiency and energy conversion efficiency. Through the thermal power unit rapid hot start system and method of the embodiment of the present invention, the start-up process of the thermal power unit is smoother, the operating cost is reduced, and the efficient operation and energy saving and consumption reduction of the overall system are achieved.

[0008] In some embodiments, the first valve group includes a first electric door and an adjustment door, and the first electric door is located upstream of the adjustment door.

[0009] In some embodiments, the first valve group further includes a first manual door, and the first manual door is located downstream of the adjustment door.

[0010] In some embodiments, the second valve group includes a second electric door and a second manual door, and the second electric door is located upstream of the second manual door.

[0011] In some embodiments, the third valve group includes a third electric door and a check valve, and the third electric door is located upstream of the check valve.

[0012] In some embodiments, the fourth valve group includes a fourth electric door and a third manual door, and the fourth electric door is located upstream of the third manual door.

[0013] The method for rapid hot start of a thermal power unit according to an embodiment of the present invention adopts the rapid hot start system for a thermal power unit, and comprises the following steps:

[0014] S1, before starting the thermal power unit, first open the third valve group, the fourth valve group and the auxiliary steam header, the auxiliary steam header supplies steam for preheating to the shaft seal steam system through the third steam supply pipeline, and the auxiliary steam header supplies steam for preheating to the interlayer steam inlet header through the fourth steam supply pipeline;

[0015] S2, the thermal power unit is started, the first valve group and the second valve group are opened, the steam main pipe supplies steam to the shaft seal steam system through the first steam supply pipeline, and the steam main pipe supplies steam to the interlayer steam inlet header through the second steam supply pipeline;

[0016] S3, after the thermal power unit reaches the required speed and temperature, it is connected to the grid for power generation, and the first valve group, the second valve group, the third valve group and the fourth valve group are closed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a rapid hot start system for a thermal power unit according to an embodiment of the present invention.

[0018] Reference numerals:

[0019] 1. Shaft seal steam system; 2. Interlayer steam inlet manifold; 3. Auxiliary steam manifold; 4. Steam main pipe; 5. First steam supply pipeline; 6. Second steam supply pipeline; 7. Third steam supply pipeline; 8. Fourth steam supply pipeline; 9. First valve group; 901. First manual door; 902. Adjustment door; 903. First electric door; 10. Second valve group; 1001. Second electric door; 1002. Second manual door; 11. Third valve group; 1101. Third electric door; 1102. Check valve; 12. Fourth valve group; 1201. Fourth electric door; 1202. Third manual door. DETAILED DESCRIPTION

[0020] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0021] Please refer to the attached Figure 1 , a system and method for rapid hot start of a thermal power unit according to an embodiment of the present invention are described in detail.

[0022] The thermal power unit rapid hot start system of the embodiment of the present invention comprises a shaft seal steam system 1, an interlayer steam inlet header 2, a steam main pipe 4 and an auxiliary steam header 3. The steam main pipe 4 is used to connect the boiler of the thermal power unit, the steam main pipe 4 is connected to the shaft seal steam system 1 through a first steam supply pipeline 5 to supply steam to the shaft seal steam system 1, the first steam supply pipeline 5 is provided with a first valve group 9, the steam main pipe 4 is connected to the interlayer steam inlet header 2 through a second steam supply pipeline 6 to supply steam to the interlayer steam inlet header 2, the second steam supply pipeline 6 is provided with a second valve group 10, the auxiliary steam header 3 is connected to the shaft seal steam system 1 through a third steam supply pipeline 7 to supply steam to the shaft seal steam system 1, the third steam supply pipeline 7 is provided with a third valve group 11, the auxiliary steam header 3 is connected to the interlayer steam inlet header 2 through a fourth steam supply pipeline 8 to supply steam to the interlayer steam inlet header 2, and the fourth steam supply pipeline 8 is provided with a fourth valve group 12.

[0023] The shaft seal steam system 1 is connected to the shaft ends of the high-pressure cylinder, medium-pressure cylinder and low-pressure cylinder of the steam turbine of the thermal power unit to provide sealing steam thereto. The interlayer steam inlet header 2 is connected to the interlayer of the steam turbine cylinder of the thermal power unit to provide heating steam thereto.

[0024] In the thermal power unit rapid hot start system of the embodiment of the present invention, the steam main pipe 4 is connected to the boiler. After the thermal power unit is ignited and started, the steam generated by the boiler flows through the steam main pipe 4. In other words, the steam source connected to the steam main pipe 4 is the main steam. The auxiliary steam header 3 is the auxiliary steam system in the thermal power unit.

[0025] The method for rapid hot start of a thermal power unit according to an embodiment of the present invention adopts the system for rapid hot start of a thermal power unit according to an embodiment of the present invention, and comprises the following steps:

[0026] S1, before starting the thermal power unit, first open the third valve group 11, the fourth valve group 12 and the auxiliary steam header 3, the auxiliary steam header 3 supplies steam for preheating to the shaft seal steam system 1 through the third steam supply pipeline 7, and the auxiliary steam header 3 supplies steam for preheating to the interlayer steam inlet header 2 through the fourth steam supply pipeline 8.

[0027] S2, the thermal power unit is started, the first valve group 9 and the second valve group 10 are opened, the steam main pipe 4 supplies steam to the shaft seal steam system 1 through the first steam supply pipeline 5, and the steam main pipe 4 supplies steam to the interlayer steam inlet header 2 through the second steam supply pipeline 6.

[0028] S3, after the thermal power unit reaches the required speed and temperature, it is connected to the grid for power generation, and the first valve group 9, the second valve group 10, the third valve group 11 and the fourth valve group 12 are closed.

[0029] The rapid hot start system of a thermal power unit in an embodiment of the present invention connects an auxiliary steam source to the system by providing an auxiliary steam header 3. Before the thermal power unit is started, steam is supplied to the interlayer steam inlet header 2 and the shaft seal steam system 1 through the auxiliary steam header 3, and the interlayer steam inlet header 2 and the shaft seal steam system 1 are preliminarily preheated. At the same time, the interlayer steam inlet header 2 is transformed into a cylinder preheating device, so as to achieve early preheating and insulation of the cylinder of the steam turbine and its shaft seal system, so that the temperature of the cylinder and its shaft seal system reaches the hot start level in advance, and the cold start of the thermal power unit is transformed into a hot start, thereby shortening the start-up time of the thermal power unit. After the thermal power unit is started, the interlayer steam inlet header 2 and the shaft seal steam system 1 are preheated and insulated again, so as to achieve secondary heating and insulation of the cylinder of the steam turbine and its shaft seal system.

[0030] The thermal power unit rapid hot start system and method of the embodiment of the present invention realizes two-stage preheating by introducing the auxiliary steam header 3 and the interlayer steam inlet header 2, so that the temperature inside and outside the cylinder reaches the hot start requirement before the start-up, thereby achieving a successful start-up of the unit and shortening the start-up time, and also improving the thermal energy utilization rate during the start-up process, ensuring that the cylinder metal temperature quickly approaches the hot start standard, avoiding the machine tripping and additional warm-up time caused by insufficient initial temperature, thereby reducing the external energy loss during the start-up period, and further improving the thermal efficiency and energy conversion efficiency. Through the thermal power unit rapid hot start system and method of the embodiment of the present invention, the start-up process of the thermal power unit is smoother, the operating cost is reduced, and the efficient operation and energy saving and consumption reduction of the overall system are achieved.

[0031] Therefore, the system and method for rapid hot start of a thermal power unit according to the embodiment of the present invention significantly shortens the time from cold start to grid connection of the thermal power unit, improves the thermal efficiency of the start-up process, and reduces start-up energy consumption and operating costs.

[0032] Further, the first valve group 9 includes a first electric door 903 and an adjustment door 902, and the first electric door 903 is located upstream of the adjustment door 902. The first electric door 903 is located at one end of the first steam supply pipeline 5 adjacent to the steam main pipe 4. When the first valve group 9 is opened, the first steam supply pipeline 5 is in a flow state. According to the actual needs of the shaft seal steam system 1, the steam flow rate can be adjusted by adjusting the door 902 to adjust and control the pressure and flow rate of the steam output from the steam main pipe 4 to the shaft seal steam system 1.

[0033] The first valve group 9 further includes a first manual door 901, which is located downstream of the adjustment door 902. The first manual door 901 is located at one end of the first steam supply pipeline 5 adjacent to the shaft seal steam system 1.

[0034] When the first valve group 9 is opened, the first electric door 903, the adjustment door 902 and the first manual door 901 are opened, and the first steam supply pipeline 5 is circulated. When the first valve group 9 is closed, the first electric door 903 is closed. If the first electric door 903 fails to close, the first manual door 901 is closed. The thermal power unit rapid hot start system of the embodiment of the present invention ensures the disconnection state of the first steam supply pipeline 5 through the setting of the first manual door 901, thereby improving the use safety and controllability of the first steam supply pipeline 5.

[0035] Further, the second valve group 10 includes a second electric door 1001 and a second manual door 1002, wherein the second electric door 1001 is located upstream of the second manual door 1002. The second electric door 1001 is located at one end of the second steam supply pipeline 6 adjacent to the steam main pipe 4, and the second manual door 1002 is located at one end of the second steam supply pipeline 6 adjacent to the interlayer steam inlet header 2.

[0036] When the second valve group 10 is opened, the second electric door 1001 and the second manual door 1002 are opened, and the second steam supply pipeline 6 is circulated. When the second valve group 10 is closed, the second electric door 1001 is closed. If the second electric door 1001 fails to close, the second manual door 1002 is closed. The thermal power unit rapid hot start system of the embodiment of the present invention ensures the disconnection state of the second steam supply pipeline 6 through the provision of the second manual door 1002, thereby improving the use safety and controllability of the second steam supply pipeline 6.

[0037] Further, the third valve group 11 includes a third electric door 1101 and a check valve 1102, wherein the third electric door 1101 is located upstream of the check valve 1102. The third electric door 1101 is located at one end of the fourth steam supply pipeline 7 adjacent to the auxiliary steam header 3, and the check valve 1102 is located at one end of the fourth steam supply pipeline 7 adjacent to the shaft seal steam system 1.

[0038] When the third valve group 11 is opened, the third electric door 1101 and the check valve 1102 are opened, and the third steam supply pipeline 7 is circulated. When the third valve group 11 is closed, the third electric door 1101 and the check valve 1102 are closed. The check valve 1102 can prevent the steam from flowing to the auxiliary steam header 3.

[0039] Further, the fourth valve group 12 includes a fourth electric door 1201 and a third manual door 1202, wherein the fourth electric door 1201 is located upstream of the third manual door 1202. The fourth electric door 1201 is located at one end of the fourth steam supply pipeline 8 adjacent to the auxiliary steam header 3, and the third manual door 1202 is located at one end of the fourth steam supply pipeline 8 adjacent to the interlayer steam inlet header 2.

[0040] When the fourth valve group 12 is opened, the fourth electric door 1201 and the third manual door 1202 are opened, and the fourth steam supply pipeline 8 is circulated. When the fourth valve group 12 is closed, the fourth electric door 1201 is closed. If the fourth electric door 1201 fails to close, the fourth manual door 1202 is closed. The thermal power unit rapid hot start system of the embodiment of the present invention ensures the disconnection state of the fourth steam supply pipeline 8 through the setting of the fourth manual door 1202, thereby improving the use safety and controllability of the fourth steam supply pipeline 8.

[0041] When the thermal power unit rapid hot start system of the embodiment of the present invention is used, first check all related equipment, including the steam main pipe 4, the shaft seal steam system 1, the interlayer steam inlet manifold 2, the auxiliary steam manifold 3, etc., to ensure that they are in good working condition. Confirm that all valve groups (the first valve group 9, the second valve group 10, the third valve group 11, and the fourth valve group 12) are in the correct initial position. Before starting the thermal power unit, open the third valve group 11 (the third electric door 1101 and the check valve 1102) to introduce auxiliary steam from the auxiliary steam manifold 3 to the shaft seal steam system 1. Open the fourth valve group 12 (the fourth electric door 1201 and the third manual door 1202), and introduce auxiliary steam into the interlayer steam inlet manifold 2 through the fourth steam supply pipeline 8 for preheating. Then, the unit is started, and the first valve group 9 (first manual door 901, adjustment door 902, first electric door 903) and the second valve group 10 (second electric door 1001 and second manual door 1002) are operated to open, and steam is supplied from the steam main pipe 4 to the shaft seal steam system 1 and the interlayer steam inlet header 2. As needed, the steam flow rate is adjusted by adjusting the adjustment door 902 to control the output from the steam main pipe 4 to the shaft seal steam system 1.

[0042] Before the thermal power unit is ignited, auxiliary steam is inputted into the interlayer steam inlet header 2 through the auxiliary steam header 3, and the inner cylinder and the high-pressure cylinder interlayer are preheated in advance by using the auxiliary steam. During the charging process, main steam is inputted into the interlayer steam inlet header 2 through the steam main pipe 4 to heat the high-pressure cylinder interlayer, increase the temperature inside and outside the cylinder, and ensure that the cylinder metal temperature reaches the hot start level before the charging. The cylinder metal temperature is monitored by the automatic control system of the thermal power unit to ensure that the startup parameters meet the hot start requirements and are adjusted according to actual conditions. Through the application of the thermal power unit rapid hot start system of the embodiment of the present invention, it is ensured that the thermal power unit continues to maintain a high temperature after the first successful charging, avoiding repeated preheating process. Once the thermal power unit reaches the required speed and temperature, it is connected to the grid for power generation and starts normal operation, and then the first valve group 9, the second valve group 10, the third valve group 11 and the fourth valve group 12 are closed.

[0043] Through the rapid hot start system of the thermal power unit of the embodiment of the present invention, the startup operation process of the thermal power unit is optimized, and the startup time (from ignition to grid connection) can be shortened by 6 hours, thereby reducing the startup energy consumption and fuel costs by about 121,000 yuan, and saving 42,000 yuan in factory electricity costs. In addition, early grid connection can increase the electricity sales revenue by 225,000 yuan, which can bring a total profit of 388,000 yuan. At the same time, the time from the turbine to reaching a fixed speed can be shortened by 2 hours, and the profit can be increased by 128,000 yuan accordingly. In addition, through the rapid hot start system of the thermal power unit of the embodiment of the present invention, when the turbine and the boiler meet the startup conditions at the same time, the problem of insufficient cylinder preheating time is avoided, ensuring the achievement of the preheating effect.

[0044] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0045] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0046] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0048] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0049] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A rapid hot start system for a thermal power unit, characterized in that: The invention comprises a shaft seal steam system (1), a sandwich steam inlet header (2), a steam main pipe (4) and an auxiliary steam header (3); the steam main pipe (4) is used to connect to the boiler of a thermal power unit; the steam main pipe (4) is connected to the shaft seal steam system (1) through a first steam supply pipeline (5) to supply steam to the shaft seal steam system (1); the first steam supply pipeline (5) is provided with a first valve group (9); the steam main pipe (4) is connected to the sandwich steam inlet header (2) through a second steam supply pipeline (6) to supply steam to the sandwich steam inlet header ( 2) steam supply, the second steam supply pipeline (6) is provided with a second valve group (10), the auxiliary steam manifold (3) is connected to the shaft seal steam system (1) through a third steam supply pipeline (7) to supply steam to the shaft seal steam system (1), the third steam supply pipeline (7) is provided with a third valve group (11), the auxiliary steam manifold (3) is connected to the interlayer steam inlet manifold (2) through a fourth steam supply pipeline (8) to supply steam to the interlayer steam inlet manifold (2), and the fourth steam supply pipeline (8) is provided with a fourth valve group (12).

2. The rapid hot start system of a thermal power unit according to claim 1, characterized in that: The first valve group (9) comprises a first electric door (903) and an adjustment door (902), wherein the first electric door (903) is located upstream of the adjustment door (902).

3. The rapid hot start system of a thermal power unit according to claim 2, characterized in that: The first valve group (9) further comprises a first manual door (901), wherein the first manual door (901) is located downstream of the adjustment door (902).

4. The rapid hot start system of a thermal power unit according to claim 1, characterized in that: The second valve group (10) comprises a second electric door (1001) and a second manual door (1002), wherein the second electric door (1001) is located upstream of the second manual door (1002).

5. The rapid hot start system of a thermal power unit according to claim 1, characterized in that: The third valve group (11) comprises a third electric door (1101) and a check valve (1102), and the third electric door (1101) is located upstream of the check valve (1102).

6. The rapid hot start system of a thermal power unit according to claim 1, characterized in that: The fourth valve group (12) comprises a fourth electric door (1201) and a third manual door (1202), and the fourth electric door (1201) is located upstream of the third manual door (1202).

7. A method for rapid hot start of a thermal power unit, characterized in that: The rapid hot start system of a thermal power unit according to any one of claims 1 to 6 comprises the following steps: S1, before starting the thermal power unit, the third valve group (11), the fourth valve group (12) and the auxiliary steam header (3) are first opened, the auxiliary steam header (3) supplies steam for preheating to the shaft seal steam system (1) through the third steam supply pipeline (7), and the auxiliary steam header (3) supplies steam for preheating to the interlayer steam inlet header (2) through the fourth steam supply pipeline (8); S2, the thermal power unit is started, the first valve group (9) and the second valve group (10) are opened, the steam main pipe (4) supplies steam to the shaft seal steam system (1) through the first steam supply pipeline (5), and the steam main pipe (4) supplies steam to the interlayer steam inlet header (2) through the second steam supply pipeline (6); S3, after the thermal power unit reaches the required speed and temperature, it is connected to the grid for power generation, and the first valve group (9), the second valve group (10), the third valve group (11) and the fourth valve group (12) are closed.

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