A steam turbine starting method

Abstract

The present invention provides a steam turbine starting method, belonging to the technical field of steam turbine starting, and includes the following steps: confirming whether the unit meets the starting conditions, determining the starting mode and unit impulse parameters, and ensuring that the unit operates strictly in accordance with the starting curve and warm-up time; clicking the start button; the steam turbine automatically locks and establishes a safe oil pressure; judging whether to perform the warm-up valve operation; opening the main steam valve; the steam turbine enters the automatic control mode and enters the steam turbine friction check; when the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is greater than the set temperature A, the target speed B and the new acceleration rate B are automatically set, and the speed is increased; when the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is less than the set temperature A, the speed is increased and the warm-up is performed in multiple times; after the steam turbine speed reaches the target speed B, a comprehensive system inspection is performed, and the automatic start is exited. This method controls the heating uniformity and thermal expansion rate of various components of the steam turbine, thereby extending the service life of the steam turbine.

Description

Technical Field

[0001] The invention belongs to the technical field of steam turbine starting, and in particular relates to a steam turbine starting method. Background Art

[0002] Steam turbines have a strict starting curve when they are started, but in reality, manual control is often used to start turbines, which is prone to errors in operation. As a result, thermal stress and metal expansion cannot be strictly heated according to the starting curve when the turbine is started. The metal thermal stress changes sharply, reducing the service life of the turbine. In addition, the staff cannot accurately grasp the operation time, resulting in insufficient warm-up time or too long warm-up time, causing time waste.

[0003] Chinese invention patent CN 106224018 A discloses a complete startup and commissioning method and system for a coal-fired steam turbine. The method includes the following steps: after completing the transmission test of the thermal signals and interlock protection for the complete startup and commissioning of the steam turbine, checking and confirming the system's test operation conditions; commissioning auxiliary equipment and systems; cold startup and commissioning of the turbine's high and low pressure cylinders; recording the relationship between lubricating oil pressure and speed; recording the reverse rotation parameters; conducting a pump switching test on the lubricating oil system and a unit warm-up test under load; performing valve tightness tests and overspeed tests; warm startup of the turbine's high and low pressure cylinders; hot startup of the turbine's high and low pressure cylinders; extremely hot startup of the turbine's high and low pressure cylinders; unit load testing; recording vibration data at each stage of the unit; and a sliding parameter shutdown test. The system includes modules for no-load and low-load commissioning, a module for turbine load commissioning, and a module for 168-hour full-load commissioning. This starting method does not take into account the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing, which will affect the heating and expansion rate of various components of the turbine and reduce the service life of the turbine; this starting method also does not take into account the impact on the operating stability of the entire unit when the turbine speed increases through the critical value. Summary of the Invention

[0004] In view of the problems existing in the above-mentioned prior art, the present invention provides a steam turbine starting method. The technical problem to be solved by the present invention is how to extend the service life of the steam turbine and enable the unit to operate according to the starting curve.

[0005] To solve the above technical problems, the present invention provides a steam turbine starting method, comprising the following steps:

[0006] Step S1: confirm whether the unit has the starting conditions, and then determine the starting method and unit start-up parameters;

[0007] Step S2: Click the start button;

[0008] Step S3: The steam turbine is automatically shut down to establish a safe oil pressure;

[0009] Step S4: judging whether to perform the valve warming operation based on the temperature of the inner wall or outer wall of the high-pressure cylinder regulating stage valve casing; when the temperature of the inner wall or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve warming operation is not performed; when the temperature of the inner wall or outer wall of the high-pressure cylinder regulating stage valve casing is less than the set temperature T1, the turbine valve casing preheating program is automatically started; when the temperature of the inner wall or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve casing preheating program is terminated. The valve warming operation can extend the life of the equipment;

[0010] Step S5: Open the main steam valve;

[0011] Step S6: Using the high and medium pressure cylinders to start together, setting the target speed A1 and the acceleration rate A1, when the turbine speed increases, the turbine cranking device is tripped, and the turbine friction check is performed;

[0012] Step S7: After the turbine friction check is completed, if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is greater than the set temperature T2, the target speed B1 and the new acceleration rate B2 are automatically set, and the speed increase begins; if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is less than the set temperature T2, the speed increase and warm-up are performed in multiple steps;

[0013] Step S8: After the turbine speed reaches the target speed B1 set in step S7, the startup is completed.

[0014] Furthermore, in step S1 , the starting mode is determined according to the cylinder temperature, including cold start, warm start, hot start and extremely hot start.

[0015] Furthermore, in step S1, the starting mode is determined according to the cylinder temperature:

[0016] 1) The metal temperature of the lower inner wall of the high-pressure inner cylinder is less than 150℃, which is considered a cold start;

[0017] 2) The metal temperature of the lower inner wall of the high-pressure inner cylinder is within the range of 150-300℃, which is considered warm start;

[0018] 3) The metal temperature of the lower inner wall of the high-pressure inner cylinder is within the range of 300-400℃, which is considered hot start;

[0019] The metal temperature of the lower inner wall of the high-pressure inner cylinder is greater than 400℃, which is considered an extremely hot start.

[0020] Furthermore, in step S1, it is necessary to determine the unit start-up parameters according to the starting mode.

[0021] Furthermore, the unit start-up parameters in step S1 include main steam pressure, main steam temperature, reheat steam pressure, reheat steam temperature and back pressure.

[0022] Furthermore, in step S6, when the turbine speed is greater than the set speed, the turbine cranking device is tripped and the turbine friction check is started. During the friction check, the turbine needs to maintain the target speed A1; if the turbine speed is greater than the set speed, the turbine cranking device is not tripped and manual shutdown is required.

[0023] Furthermore, the multiple speed increases and warm-up steps in step S7 include:

[0024] First speed increase and warm-up: Set the target speed C1 and speed increase rate C2, and continue to increase the turbine speed to the target speed C1, and then warm up;

[0025] Second speed increase and warm-up: Set the target speed D1 and speed increase rate D2, and continue to increase the speed of the turbine to the target speed D1, and then perform high-speed warm-up;

[0026] The third speed increase: After the high-speed warm-up is completed, the target speed B1 and the speed increase rate E2 are set, and the turbine continues to increase the speed to the target speed E1.

[0027] Furthermore, the following conditions are required for high-speed warm-up:

[0028] a) The metal temperature of the lower inner wall of the medium-pressure exhaust port is greater than 130°C and the machine is kept warm for 60 minutes;

[0029] b) The metal temperature after the regulating stage on the upper inner wall of the high-pressure inner cylinder is greater than 250°C;

[0030] c) The expansion of high and medium pressure cylinders is greater than 7mm;

[0031] d) The expansion difference between high and medium pressure is less than 3.5mm and tends to be stable.

[0032] Furthermore, when the turbine speed exceeds the critical speed, the speed increase rate is increased, and the unit should quickly and smoothly pass through the critical speed of the shafting, which is the target speed D1 or the target speed B1.

[0033] Furthermore, when the speed passes the target speed D1, when the bearing cover vibration exceeds 0.1mm or the shaft vibration exceeds 0.25mm, the machine is immediately shut down. It is strictly forbidden to force it through or reduce the speed to warm it up; stop the top shaft oil pump.

[0034] Furthermore, the starting conditions in step S1 include the following:

[0035] 1. All main protections of the steam turbine have been put into operation.

[0036] 2. The turbine is continuously cranked for more than 2 hours.

[0037] 3. The temperature difference between the upper and lower cylinders of the turbine shall not exceed 25°C.

[0038] 4. The main steam temperature before the main steam valve is overheated by more than 80℃.

[0039] 5. The main steam valve and regulating valve are all closed, and the main steam and regulating valve command feedback are consistent, with a deviation of no more than 0.5%.

[0040] 6. The steam extraction electric valves and steam extraction check valves of each steam extraction section are closed, and the steam extraction electric valves before and after the drain are opened.

[0041] 7. The high and low pressure bypass are operating normally and are automatically put into operation.

[0042] 8. When the EH oil pump is running, the oil pressure of the EH main pipe is greater than 13.5MPa.

[0043] 9. All the drain valves on the turbine side are open.

[0044] 10. The turbine speed determines the cranking status and the speed should not exceed 5rpm.

[0045] 11. There are no conditions prohibiting the start-up of the steam turbine.

[0046] 12. The condenser back pressure is less than 25kPa.

[0047] 13. The metal temperature of the lower inner wall of the high-pressure outer cylinder is greater than 150℃ and less than 300℃, the high-pressure cylinder preheating valve is closed, and the VV valve is opened.

[0048] Furthermore, the main protection includes the following:

[0049] 1) Low lubricating oil pressure protection;

[0050] 2) EH oil low pressure protection;

[0051] 3) Large axial displacement protection;

[0052] 4) Shaft vibration protection;

[0053] 5) Steam turbine overspeed protection;

[0054] 6) DEH power failure protection;

[0055] 7) DEH trips and requests protection;

[0056] 8) High and low pressure cylinder expansion differential protection;

[0057] 9) High pressure cylinder exhaust temperature protection;

[0058] 10) Support high temperature protection;

[0059] 11) Thrust bearing high temperature protection;

[0060] 12) Condenser back pressure high trip protection.

[0061] A steam turbine starting method of the present invention automatically performs the original manual rush-start operation according to steps, reduces the operation workload of operating personnel, prevents the occurrence of erroneous operations, and improves safety; determines the starting mode according to the cylinder temperature, and then determines the unit rush-start parameters according to the starting mode so that the unit is operated strictly according to the starting curve and warm-up time, avoiding the intermediate process caused by lax time control due to human operation, resulting in insufficient warm-up time, or time waste caused by untimely operation of the operator, thereby realizing standardized operation and intelligent control; strictly controls the change rate of cylinder stress during the steam turbine rush-start process, controls the heating uniformity and thermal expansion rate of various components of the steam turbine, thereby extending the service life of the steam turbine; strictly controls the starting time of each stage of the steam turbine startup, and shortens the unit startup time. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 The present invention is a flow chart of a steam turbine starting method. DETAILED DESCRIPTION

[0063] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0064] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0065] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0066] In the present invention, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; they may refer to direct connection or indirect connection through an intermediate medium; they may refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0067] In order to better understand the purpose, structure and function of the present invention, a steam turbine starting method of the present invention is further described in detail below with reference to the accompanying drawings.

[0068] Example 1:

[0069] like Figure 1 As shown, the present invention provides a steam turbine starting method, comprising the following steps:

[0070] Step S1: confirm whether the unit has the starting conditions, and then determine the starting method and unit start-up parameters;

[0071] Step S2: Click the start button;

[0072] Step S3: The steam turbine is automatically shut down to establish a safe oil pressure;

[0073] Step S4: Determine whether to perform the valve warming operation based on the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve warming operation is not performed; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing is less than the set temperature T1, the turbine valve casing preheating program is automatically started; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve casing preheating program is ended.

[0074] Step S5: Open the main steam valve;

[0075] Step S6: Using the high and medium pressure cylinders to start together, setting the target speed A1 and the acceleration rate A1, when the turbine speed increases, the turbine cranking device is tripped, and the turbine friction check is performed;

[0076] Step S7: After the turbine friction check is completed, if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is greater than the set temperature T2, the target speed B1 and the new acceleration rate B2 are automatically set, and the speed increase begins; if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is less than the set temperature T2, the speed increase and warm-up are performed in multiple steps;

[0077] Step S8: After the turbine speed reaches the target speed B1 set in step S7, the startup is completed.

[0078] Example 2:

[0079] like Figure 1 As shown, the present invention provides a steam turbine starting method, comprising the following steps:

[0080] Step S1: confirm whether the unit has the starting conditions, and then determine the starting method and unit start-up parameters;

[0081] Step S2: Click the DEH operation screen start button;

[0082] Step S3: The steam turbine is automatically shut down to establish a safe oil pressure;

[0083] Step S4: judging whether to perform the valve warming operation based on the temperature of the inner wall or outer wall of the high-pressure cylinder regulating stage valve casing; when the temperature of the inner wall or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve warming operation is not performed; when the temperature of the inner wall or outer wall of the high-pressure cylinder regulating stage valve casing is less than the set temperature T1, the turbine valve casing preheating program is automatically started; when the temperature of the inner wall or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve casing preheating program is terminated;

[0084] Step S5: Open the main steam valve;

[0085] Step S6: The steam turbine enters the automatic control mode, adopts the joint start of high and medium pressure cylinders, sets the target speed A1 and the acceleration rate A1, and when the turbine speed increases, the turbine cranking device trips and the turbine friction check is performed;

[0086] Step S7: After the turbine friction check is completed, if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is greater than the set temperature T2, the target speed B1 and the new acceleration rate B2 are automatically set, and the speed increase begins; if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is less than the set temperature T2, the speed increase and warm-up are performed in multiple steps;

[0087] Step S8: After the turbine speed reaches the target speed B1 set in step S7, the startup is completed.

[0088] Example 3:

[0089] like Figure 1 As shown, the present invention provides a steam turbine starting method, comprising the following steps:

[0090] Step S1: confirm whether the unit has the starting conditions, and then determine the starting method and unit start-up parameters;

[0091] Step S2: Click the start button;

[0092] Step S3: The steam turbine is automatically shut down to establish a safe oil pressure;

[0093] Step S4: Determine whether to perform the valve warming operation based on the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve warming operation is not performed; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing is less than the set temperature T1, the turbine valve casing preheating program is automatically started; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve casing preheating program is ended.

[0094] Step S5: Open the main steam valve;

[0095] Step S6: Using the high and medium pressure cylinders to start together, setting the target speed A1 and the acceleration rate A1, when the turbine speed increases, the turbine cranking device is tripped, and the turbine friction check is performed;

[0096] Step S7: After the turbine friction check is completed, if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is greater than the set temperature T2, the target speed B1 and the new acceleration rate B2 are automatically set, and the speed increase begins; if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is less than the set temperature T2, the speed increase and warm-up are performed in multiple steps;

[0097] Step S8: After the turbine speed reaches the target speed B1 set in step S7, the startup is completed and the automatic startup is exited; the AC lubricating oil pump is manually stopped.

[0098] This embodiment differs from the first embodiment in that:

[0099] The starting conditions in step S1 include the following:

[0100] 1. All main protections of the steam turbine have been put into operation.

[0101] 2. The turbine is continuously cranked for more than 2 hours.

[0102] 3. The temperature difference between the upper and lower cylinders of the turbine shall not exceed 25°C.

[0103] 4. The main steam temperature before the main steam valve is overheated by more than 80℃.

[0104] 5. The main steam valve and regulating valve are all closed, and the main steam and regulating valve command feedback are consistent, with a deviation of no more than 0.5%.

[0105] 6. The steam extraction electric valves and steam extraction check valves of each steam extraction section are closed, and the steam extraction electric valves before and after the drain are opened.

[0106] 7. The high and low pressure bypass are operating normally and are automatically put into operation.

[0107] 8. When the EH oil pump is running, the oil pressure of the EH main pipe is greater than 13.5MPa.

[0108] 9. All the drain valves on the turbine side are open.

[0109] 10. The turbine speed determines the cranking status and the speed should not exceed 5rpm.

[0110] 11. There are no conditions prohibiting the start-up of the steam turbine.

[0111] 12. The condenser back pressure is less than 25kPa.

[0112] 13. The metal temperature of the lower inner wall of the high-pressure outer cylinder is greater than 150℃ and less than 300℃, the high-pressure cylinder preheating valve is closed, and the VV valve is opened.

[0113] The main protection includes the following:

[0114] 1) Low lubricating oil pressure protection;

[0115] 2) EH oil low pressure protection;

[0116] 3) Large axial displacement protection;

[0117] 4) Shaft vibration protection;

[0118] 5) Steam turbine overspeed protection;

[0119] 6) DEH power failure protection;

[0120] 7) DEH trips and requests protection;

[0121] 8) High and low pressure cylinder expansion differential protection;

[0122] 9) High pressure cylinder exhaust temperature protection;

[0123] 10) Support high temperature protection;

[0124] 11) Thrust bearing high temperature protection;

[0125] 12) Condenser back pressure high trip protection.

[0126] Example 4:

[0127] like Figure 1 As shown, the present invention provides a steam turbine starting method, comprising the following steps:

[0128] Step S1: confirm whether the unit has the starting conditions, and then determine the starting method and unit start-up parameters;

[0129] Step S2: Click the start button;

[0130] Step S3: The steam turbine is automatically shut down to establish a safe oil pressure;

[0131] Step S4: Determine whether to perform the valve warming operation based on the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve warming operation is not performed; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing is less than the set temperature T1, the turbine valve casing preheating program is automatically started; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve casing preheating program is ended.

[0132] Step S5: Open the main steam valve;

[0133] Step S6: Using the high and medium pressure cylinders to start together, setting the target speed A1 and the acceleration rate A1, when the turbine speed increases, the turbine cranking device is tripped, and the turbine friction check is performed;

[0134] Step S7: After the turbine friction check is completed, if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is greater than the set temperature T2, the target speed B1 and the new acceleration rate B2 are automatically set, and the speed increase begins; if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is less than the set temperature T2, the speed increase and warm-up are performed in multiple steps;

[0135] Step S8: After the turbine speed reaches the target speed B1 set in step S7, the startup is completed.

[0136] This embodiment differs from the first embodiment in that:

[0137] In step S1, the starting mode is determined according to the cylinder temperature:

[0138] 1) The metal temperature of the lower inner wall of the high-pressure inner cylinder is less than 150℃, which is considered a cold start;

[0139] 2) The metal temperature of the lower inner wall of the high-pressure inner cylinder is within the range of 150-300℃, which is considered warm start;

[0140] 3) The metal temperature of the lower inner wall of the high-pressure inner cylinder is within the range of 300-400℃, which is considered hot start;

[0141] 4) The metal temperature of the lower inner wall of the high-pressure inner cylinder is greater than 400℃, which is an extremely hot start.

[0142] In step S2, the unit start-up parameters are determined according to the starting mode:

[0143] During cold start, the unit run parameters are: main steam pressure 3.45MPa; main steam temperature: 320℃; reheat steam pressure: 0.686MPa; reheat steam temperature: 237℃; back pressure: 25KPa;

[0144] During warm start, the unit run parameters are: main steam pressure 7.84MPa; main steam temperature: 410℃; reheat steam pressure: 0.686MPa; reheat steam temperature: 327℃; back pressure: 25KPa;

[0145] During hot start, the unit run parameters are: main steam pressure 9.81; main steam temperature: 510℃; reheat steam pressure: 0.686MPa; reheat steam temperature: 487℃; back pressure: 25KPa;

[0146] During the extremely hot start-up, the unit start-up parameters are: main steam pressure 11.76MPa; main steam temperature: 510℃; reheat steam pressure: 0.686MPa; reheat steam temperature: 487℃; back pressure: 25KPa.

[0147] The set temperature T1 in step S4 is 150°C.

[0148] Example 5:

[0149] like Figure 1 As shown, the present invention provides a steam turbine starting method, comprising the following steps:

[0150] Step S1: confirm whether the unit has the starting conditions, and then determine the starting method and unit start-up parameters;

[0151] Step S2: Click the start button;

[0152] Step S3: The steam turbine is automatically shut down to establish a safe oil pressure;

[0153] Step S4: Determine whether to perform the valve warming operation based on the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve warming operation is not performed; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing is less than the set temperature T1, the turbine valve casing preheating program is automatically started; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve casing preheating program is ended.

[0154] Step S5: Open the main steam valve;

[0155] Step S6: Using the high and medium pressure cylinders to start together, setting the target speed A1 and the acceleration rate A1, when the turbine speed increases, the turbine cranking device is tripped, and the turbine friction check is performed;

[0156] Step S7: After the turbine friction check is completed, if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is greater than the set temperature T2, the target speed B1 and the new acceleration rate B2 are automatically set, and the speed increase begins; if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is less than the set temperature T2, the speed increase and warm-up are performed in multiple steps;

[0157] Step S8: After the turbine speed reaches the target speed B1 set in step S7, the startup is completed.

[0158] This embodiment differs from the first embodiment in that:

[0159] In step S6, the turbine control enters the automatic control mode, single valve control, sets the target speed A1 to 490rpm / min, the acceleration rate A2 to 100rpm / min, and when the turbine speed is greater than the set speed, the turbine cranking device is tripped, the cranking is in place signal is taken, and the turbine friction check is started. During the friction check, the turbine needs to maintain the target speed A1 for one minute; when the turbine speed is greater than the set speed, the turbine cranking device is not tripped, and manual shutdown is required; the set speed is 50rpm / min.

[0160] Example 6:

[0161] like Figure 1As shown, the present invention provides a steam turbine starting method, comprising the following steps:

[0162] Step S1: confirm whether the unit has the starting conditions, and then determine the starting method and unit start-up parameters;

[0163] Step S2: Click the start button;

[0164] Step S3: The steam turbine is automatically shut down to establish a safe oil pressure (delay 30 seconds, proceed to the next step);

[0165] Step S4: Determine whether to perform the valve warming operation based on the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve housing; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve housing is greater than the set temperature T1, the valve warming operation is not performed; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve housing is less than the set temperature T1, the turbine valve housing preheating program is automatically started; when the temperature of the inner or outer wall of the high-pressure cylinder regulating stage valve housing is greater than the set temperature T1, the valve housing preheating program is terminated (delay 10 seconds, and proceed to the next step);

[0166] Step S5: Open the main steam valve (delay 30S, proceed to the next step);

[0167] Step S6: Using the high and medium pressure cylinders to start together, setting the target speed A1 and the acceleration rate A1, when the turbine speed increases, the turbine cranking device is tripped, and the turbine friction check is performed;

[0168] Step S7: After the turbine friction check is completed, if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is greater than the set temperature T2, the target speed B1 and the new acceleration rate B2 are automatically set, and the speed increase begins; if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is less than the set temperature T2, the speed increase and warm-up are performed in multiple steps;

[0169] Step S8: After the turbine speed reaches the target speed B1 set in step S7, the startup is completed.

[0170] This embodiment differs from the first embodiment in that:

[0171] In step S7, if the metal temperature after the adjustment stage on the upper inner wall of the high-pressure inner cylinder is greater than 250°C, the target speed is set to 3000 rpm / min, the acceleration rate is set to 150 rpm / min, and the speed is increased. If the metal temperature after the adjustment stage on the upper inner wall of the high-pressure inner cylinder is less than 250°C, the speed is increased and the engine is warmed up in multiple steps.

[0172] First speed increase and warm-up: Set the target speed C1 and the speed increase rate C2, and continue to increase the turbine speed to the target speed C1 and warm up for 30 minutes; the target speed C1 is 1200 rpm / min, and the speed increase rate C2 is 100 rpm / min;

[0173] Second speed increase and warm-up: Set the target speed D1 and the speed increase rate D2, and the turbine will continue to speed up to the target speed D1 and perform high-speed warm-up for 60 minutes; the target speed D1 is 2200 rpm / min, and the speed increase rate D2 is 100 rpm / min; when the critical speed is exceeded, the speed increase rate automatically changes to 250-300 rpm;

[0174] The unit should pass through the critical speed of the shaft system quickly and smoothly. When passing through the critical speed, if the bearing cover vibration exceeds 0.1mm or the shaft vibration exceeds 0.25mm, the unit should be shut down immediately. It is strictly forbidden to force it through or slow down to warm up, and the top shaft oil pump should be stopped.

[0175] The third speed increase: After the high-speed warm-up is completed, the target speed B1 and the speed increase rate E2 are set, and the turbine continues to increase the speed to the target speed E; the target speed B1 is 3000rpm / min, and the speed increase rate E2 is 100rpm / min; when the critical speed is exceeded, the speed increase rate is automatically adjusted to 300rpm / min to quickly pass the critical speed.

[0176] Among them, the conditions for high-speed warm-up are as follows:

[0177] a) The metal temperature of the lower inner wall of the medium-pressure exhaust port should be greater than 130°C and the machine should be kept warm for 60 minutes;

[0178] b) The metal temperature after the regulating stage on the upper inner wall of the high-pressure inner cylinder is greater than 250°C;

[0179] c) The expansion of high and medium pressure cylinders is greater than 7mm;

[0180] d) The expansion difference between high and medium pressure is less than 3.5mm and tends to be stable.

[0181] A steam turbine starting method of the present invention automatically performs the original manual starting operation according to steps, reduces the operation workload of operating personnel, prevents the occurrence of erroneous operations, and improves safety; enables the unit to be operated strictly according to the starting curve and warm-up time, avoids lax time control caused by personnel operation in the intermediate process, resulting in insufficient warm-up time, or time waste caused by untimely operation of operators, thereby realizing standardized operation and intelligent control; strictly controls the change rate of cylinder stress in the steam turbine starting process, controls the heating uniformity and thermal expansion rate of various components of the steam turbine, thereby extending the service life of the steam turbine; strictly controls the starting time of each stage of the steam turbine starting, and shortens the starting time of the unit.

[0182] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A steam turbine starting method, characterized in that: The following steps are involved: Step S1: Confirm whether the unit has the starting conditions, and then determine the starting method and unit start-up parameters; in step S1, the starting method is determined according to the cylinder temperature: 1) The metal temperature of the lower inner wall of the high-pressure inner cylinder is less than 150℃, which is considered a cold start; 2) The metal temperature of the lower inner wall of the high-pressure inner cylinder is within the range of 150-300℃, which is considered warm start; 3) The metal temperature of the lower inner wall of the high-pressure inner cylinder is within the range of 300-400℃, which is considered hot start; The metal temperature of the lower inner wall of the high-pressure inner cylinder is greater than 400℃, which is considered to be an extremely hot start; Step S2: Click the start button; Step S3: The steam turbine is automatically shut down to establish a safe oil pressure; Step S4: judging whether to perform the valve warming operation based on the temperature of the inner wall or outer wall of the high-pressure cylinder regulating stage valve casing; when the temperature of the inner wall or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve warming operation is not performed; when the temperature of the inner wall or outer wall of the high-pressure cylinder regulating stage valve casing is less than the set temperature T1, the turbine valve casing preheating program is automatically started; when the temperature of the inner wall or outer wall of the high-pressure cylinder regulating stage valve casing is greater than the set temperature T1, the valve casing preheating program is terminated; Step S5: Open the main steam valve; Step S6: Using the high and medium pressure cylinders to start together, setting the target speed A1 and the acceleration rate A1, when the turbine speed increases, the turbine cranking device is tripped, and the turbine friction check is performed; Step S7: After the turbine friction check is completed, if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is greater than the set temperature T2, the target speed B1 and the acceleration rate B2 are automatically set, and the speed increase begins; if the metal temperature behind the regulating stage of the upper inner wall of the high-pressure inner cylinder is less than the set temperature T2, the speed increase and warm-up are performed in multiple steps; the multiple speed increases and warm-up in step S7 include: First speed increase and warm-up: Set the target speed C1 and speed increase rate C2, and continue to increase the turbine speed to the target speed C1, and then warm up; Second speed increase and warm-up: Set the target speed D1 and speed increase rate D2, and continue to increase the speed of the turbine to the target speed D1, and then perform high-speed warm-up; The third speed increase: After the high-speed warm-up is completed, the target speed B1 and the speed increase rate E2 are set, and the turbine continues to increase the speed to the target speed E1; Step S8: After the turbine speed reaches the target speed B1 set in step S7, the startup is completed.

2. The steam turbine starting method according to claim 1, characterized in that: In step S1 , the starting mode is determined according to the cylinder temperature, including cold start, warm start, hot start and extremely hot start.

3. The steam turbine starting method according to any one of claims 1 to 2, characterized in that: In step S1, the unit start-up parameters need to be determined according to the starting method.

4. The steam turbine starting method according to claim 3, characterized in that: The unit start-up parameters in step S1 include main steam pressure, main steam temperature, reheat steam pressure, reheat steam temperature and back pressure.

5. The steam turbine starting method according to claim 1, characterized in that: In step S6, when the turbine speed is greater than the set speed, the turbine cranking device is tripped and the turbine friction check is started. During the friction check, the turbine needs to maintain the target speed A1; if the turbine speed is greater than the set speed, the turbine cranking device is not tripped and manual shutdown is required.

6. The steam turbine starting method according to claim 1, characterized in that: The following conditions are required for high-speed warm-up: a) The metal temperature of the lower inner wall of the medium-pressure exhaust port is greater than 130°C and the machine is kept warm for 60 minutes; b) The metal temperature after the regulating stage on the upper inner wall of the high-pressure inner cylinder is greater than 250°C; c) The expansion of high and medium pressure cylinders is greater than 7mm; d) The expansion difference between high and medium pressure is less than 3.5mm and tends to be stable.

7. The steam turbine starting method according to claim 1, characterized in that: When the turbine speed exceeds the critical speed, increase the speed increase rate. The unit should quickly and smoothly pass through the critical speed of the shafting. The critical speed is the target speed D1 or the target speed B1.

8. The steam turbine starting method according to claim 7, characterized in that: When the speed passes the target speed D1, when the bearing cover vibration exceeds 0.1mm or the shaft vibration exceeds 0.25mm, immediately shut down the machine. It is strictly forbidden to force it through or slow down to warm up, and stop the top shaft oil pump.

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