Turbine Operating Procedures
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Operating Procedures for Gas-Pressurized Steam Turbine Compressor Units Chapter 1: Content and Scope of Application 1. Subject Matter and Scope of Application These standards specify the responsibilities related to the gas-pressurizing compressors in a 600,000-ton methanol production facility, as well as the process flow, operating procedures, methods for dealing with abnormal situations, and safety requirements. Chapter 2: Job Responsibilities and Scope 1. Job Responsibilities The operators must be thoroughly familiar with the structure of all equipment, the layout of pipelines, the process flow, control parameters, and control methods in the plant area. They should also have a good understanding of the safety systems, and be able to carry out startup, shutdown operations, as well as handle accidents independently ； During normal production, it is necessary to operate accurately, keep proper records, inspect the equipment on site and carry out regular maintenance, as well as address various operational incidents promptly to ensure the proper functioning of the production facilities. 2. Scope of duties: The scope of responsibility for the gas compression turbine compressor unit includes maintaining and operating equipment such as turbines, compressors, lubrication oil pumps, condensate water pumps, dry gas seals, inter-stage coolers, water coolers, and condensers. It also involves managing the use and maintenance of fire-fighting equipment and gas masks in this area, as well as ensuring that there are no leaks or other issues in this unit. Chapter 3: Process Flow 1. Water gas from the gas holder → enters the first-stage inlet separator → compressed by the first-stage compressor → cooled in the first-stage gas cooler → proceeds to the second-stage inlet separator → compressed by the second-stage compressor → cooled in the second-stage gas cooler → goes to the third-stage inlet separator → compressed by the third-stage compressor → cooled in the final gas cooler → proceeds to the final separator → TSA (Temperature-Dependent Adsorption). 2. Process objective: Increase the pressure of the water gas coming from the gas holder, which is 3 KPa, to 0.548 MPa, and then send it to TSA. Chapter 3: Operating Procedures 1. Working Principle of the Compressor Unit A centrifugal compressor is a type of rotary impeller machine that relies on the high-speed rotation of the impeller to subject the gas to centrifugal force, thereby imparting pressure energy on it. The process gas enters the inlet volute of each stage of the compressor, flows through the inlet guide vanes, which direct the gas at an appropriate angle toward the next stage of the impeller. Due to centrifugal force, the gas is ejected from the edge of the impeller at high speed into the channel formed by the inlet guide vanes and a set of partitions; subsequently, the gas passes through a swirler and an annular channel to reach the next stage of the impeller. As the annular channels through the partition expand, the gas flow velocity slows down, thereby converting some of the kinetic energy into pressure energy. Through such repeated compression at various stages, a certain outlet pressure is achieved to meet the requirements of the process users. 2. Introduction to the compressor’s main structure: This 3MCL1206 model compressor features a single cylinder with three stages and six compression steps; its nominal diameter is 1200 mm. The casing is of horizontal split type. The compressor mainly consists of a stator (housing, diaphragm, balance disk seals), a rotor (shaft, impeller, sleeve, coupling, balance disk), as well as support bearings, thrust bearings, and shaft end seals. This machine features a centrifugal structure and was independently designed and manufactured by Shenyang Blower Group – Shenyang Turbo Machinery Co., Ltd. 3. The unit model is 3MCL1206; the compressor consists of three sections, each with 6 stages (a total of 6 impellers). The casing is of the horizontally split welded type, and the shaft end sealing is achieved using dry gas seals provided by Dalian Huayang Co., Ltd. The control system for these dry gas seals is also supplied by Dalian Huayang Co., Ltd. The prime mover is a turbine produced by Hangzhou Zhongneng Turbine Power Co., Ltd. A diaphragm coupling is used to connect the lightweight unit to the compressor. The entire unit is supplied with lubricating oil by the lubricating oil station. The compressor and turbine are mounted on a common base. 4. Technical Parameters of Centrifugal CompressorName | Number of Digits | Value | Remarks
Model: 3MCL120; Number of Units: 2; Model 2H2200 – Water-gas compression compressor
Rotation direction: Clockwise when viewed from the turbine side toward the compressor
Equipment tag number: J621A/B01
Stage number: 6
Rated power: 10,528 KW
Rated flow rate: 2,138.4 Nm3/min
Inlet temperature: 40°C
Rated rotational speed: 4,485 r/min
Inlet pressure: 0.101 MPa
Maximum continuous rotational speed: 4,709 r/min
Working medium: Water-gas
Outlet pressure: 0.548 MPa
Tripping rotational speed: 5,180 r/min
First-order critical rotational speed: 1,899 r/min
Chapter 4: Startup with Dry Gas Sealing
1. Dry gas sealing process
1.1 Main sealing gas process: 0.6 MPa nitrogen gas, filtered through filter F1 (or F2) with a filtration precision of 1 u, and then reduced to 0.3 MPa by a self-acting pressure regulator PCV1. This gas is divided into four streams; two of these streams serve as the main sealing gas and pass through FT-621404 and FT621405 respectively to reach the main sealing chambers on the high-pressure and low-pressure sides. When the compressor is running, the pumping action of the spiral grooves engraved on the end face of the rotating ring opens the sealing end face, while also serving to lubricate and cool it. The normal consumption of nitrogen for the main seal at one end is approximately 1 Nm3/h. 1.2 Buffer gas flow: The nitrogen gas filtered by filter F1 (or 2) is used as buffer gas; two of these streams pass through orifice plate assemblies SO3 and SO4 to have their pressure reduced and flow rate controlled, before entering the pre-seal chambers at the high-pressure and low-pressure ends respectively. The nitrogen entering the pre-seal chamber is primarily intended to prevent contamination of the seal faces by the process gas inside the machine. The sonic orifices SO3 and SO4 keep the nitrogen consumption at around 10 Nm³/h. 1.3 Isolation gas flow: Nitrogen at 0.6 MPa is filtered through filter F3 (or F4) and then divided into two streams to serve as isolation gas. After being reduced in pressure and throttled by orifice plates SO1 and SO2, it enters the rear sealing chambers on the high-pressure side and low-pressure side respectively. The isolation gas that enters the rear sealing chamber mixes, in part, with the main sealing gas that leaks outward after passing through the inner labyrinth, and then is vented to the outside; the other part passes through the outer labyrinth and is vented via the bearing ventilation ports. This gas is intended primarily to prevent lubricant from contaminating the sealing surfaces. The sonic orifice plates SO1 and SO2 control the nitrogen consumption; with the seal at one end, the nitrogen consumption is around 40 Nm3/h. 2 Preparations before commissioning: After the installation of the dry gas seal system and the connection pipelines to the unit is completed, they should be stripped of acid residues and cleaned using steam. After the pipeline is reset and before the seal body is installed, the pipeline should be thoroughly purged with filtered clean gas to prevent solid impurities such as welding slag from entering the seal chamber. The cleanliness level of the main seal gas pipeline should be 1u; a clean white cloth can be used at the outlet to check for any visible dirt, and it is considered acceptable if no such dirt is present within five minutes. After purging, close all valves and stay in standby mode. Install pressure instruments and transmitters at the site (open the pressure tapping valve). Note: During normal operation, the post-isolation gas must not be interrupted. After the compressor stops, the post-isolation gas must be shut off after the supply of lubricating oil has ceased. 3 Dry gas seal startup: Before air is introduced into the machine, opening valves V1, V2 (or V3, V4), V5, V6, V9, V10, V14, and V15 activates the main seal gas, while opening valves V12 and V13 activates the buffer gas. At this time, the pressure gauge PG-621406 indicates that the pressure of the nitrogen supply after passing through the filter F1 (or F2) and being reduced by the self-acting pressure regulator is approximately 0.3 MPa. PG-621408 and PG-621409 show that the nitrogen pressure after passing through the orifice plate assemblies SO3 and SO4 is about 0.1 MPa; PG-621410 and PG-621411 indicate a value of around 0.3 MPa. The flow meters FT-621404 and FT-621405 show almost zero readings. 4 Alarms and handling measures for dry gas seals: 4.1 Alarm and interlock for the pressure difference between the main seal gas and the buffer gas at the high-pressure side: PDT-621402 is used to measure the pressure difference between these two gases; the normal value for this difference is ≥0.2 MPa. An alarm is triggered when the difference drops to 0.1 MPa, and an emergency shutdown is initiated when it falls to 0.05 MPa. 4.2 Seal gas filter clogging alarm: PDT621401 is used to detect whether the nitrogen (main seal gas and isolation gas) filter F1 (or F2) is clogged; an alarm is triggered when the differential pressure reaches ≥40 KPa, at which point the filter element needs to be replaced. 4.3 Main seal gas flow rate alarm: FT-621404 and FT-621405 are used to measure the flow rate of the main seal gas. The normal flow rate for this gas should be ≤ 1 Nm3/h; an alarm is triggered when the flow rate reaches 2.5 Nm3/h. If the pressure difference between the main seal gas and the buffer gas remains normal in such cases, operations can continue, as there are many reasons for high leakage rates, such as end face deformation, minor scratches, or excessive shaft displacement that leads to poor tracking between the rotating and stationary rings. Even if the leakage rate is a bit high in these situations, the seal still functions properly. Of course, while it continues to operate, the following tasks must be carried out: verify whether the alarm values are accurate, check for leaks in the pipelines, and ensure that the float of the flow meter is not stuck ； If the alarm value is indeed true, prepare to shut down the equipment for inspection and replace parts, as staying in an elevated alarm state for an extended period indicates that the seal is not functioning properly and could deteriorate at any time. 4.4 Alarm for low pressure of nitrogen gas after filtration: PT-621403 is used to measure the pressure of the nitrogen gas after filtration; an alarm is triggered when this pressure falls below 0.4 MPa. If such an alarm occurs before the system is started, the oil pump shall not be activated. During normal operation, if an alarm is issued, it is necessary to check whether the nitrogen gas pressure is within the normal range. 4.5 Precautions: 10 minutes before putting the lubricating oil into use, post-isolation gas must be supplied first; this supply must not be interrupted during normal operation ； After the compressor stops, the post-isolation gas must not be shut off until at least 10 minutes after the lubricating oil supply has ceased and there is no more oil flowing in the oil return line ； The isolation valves before and after the flow meter must be opened slowly to prevent the float from getting stuck due to the impact of pressurized airflow ； The shut-off valves before and after the filter must be opened slowly to prevent the filter element from being damaged by pressurized airflow ； The filter should be inspected daily; when the pointer indicates the red area, it is necessary to switch to the backup filter and replace the element of the clogged filter so that it can be used as a backup ； Maximum operating time of the filter element: 1 year ； Residual gas in the filter is harmful to the body; exercise caution when replacing it. Chapter 5: Startup of the Oil System
1. Start the oil pump at the oil station. Adjust the oil temperature using the oil station heater or oil cooler. A Pt100 temperature sensor is installed on the outlet pipe of the lubricating oil cooler to monitor the lubricating oil temperature. The temperature sensor sends the temperature signal to the control room for display and monitoring. An audible and visual alarm is triggered when the temperature exceeds the set value. A temperature of ≥35°C is considered normal; an alarm is issued when the temperature reaches ≥55°C. The lubricating oil tank level alarm circuit uses a level switch to send signals to the control room; when the level is below the set alarm level, an audible and visual alarm is triggered, with an alarm triggered at a set value of ≤833 (measured from the upper surface of the flange). A primary oil pressure control circuit is provided at the outlet of the lubricating oil pump, utilizing pressure regulation before the valve. The function of this primary oil pressure is to supply a stable oil pressure to the turbine control oil system, with a set value of 1.1 MPa. The secondary oil pressure control circuit features a main pipe oil pressure control circuit installed on the outlet main pipe of the oil station; it uses pressure control after the valve to regulate the oil pressure in the lubricating oil main pipe, thereby ensuring an appropriate supply pressure for the machine units, with a set value of 0.3 MPa. The function of the lubricating oil filter differential pressure alarm circuit is to monitor the operation of the oil filter. When the differential pressure across the oil filter exceeds the normal value, the differential pressure transmitter sends the measured value to the control room display for monitoring; when this value exceeds the set threshold, an audible and visual alarm is triggered, with an alarm being issued when the differential pressure is ≥0.15 MPa. Adjust the main oil pressure in the inlet main pipe to 0.8∽1.2 MPa (the normal lubricating oil pressure is 0.245 MPa) as well as the oil pressures in each supply branch pipe, via the oil stations and control valves; check the sight glasses at the outlets of each return pipe to ensure that oil is flowing. The standby oil pump and auxiliary oil pump are interlocked in the on position. 2. Start the cooling system; open the inlet and outlet valves as well as the air valves of each gas cooler, condenser, and subcooler. Close the air valves once water begins to flow from them. The medium temperature is adjusted at runtime based on the pressure and flow rate of the process gas. Chapter 6 Startup of the steam turbine compressor unit
1. On-site verification of startup conditions: pressures and temperatures at various points of the lubricating oil system ； Dry gas seal balance line pressure difference, high and low pressure cylinder dry gas seal exhaust flow rate ； The anti-surge valve is fully open. Once the above conditions are met, stop the turnkey machine on-site; in the control room, press the “Reset” button. All valves of the compressor unit will open automatically. Then, open the quick-closing valve on-site – the conditions for startup are now fulfilled. 2. Contact the control room to start the turbine, perform low-speed warm-up at 1000 r/min, and increase the speed in accordance with the temperature rise curve (see details in turbine startup procedures). Chapter 7: Methods for Handling Abnormal Phenomena – Causes of Faults and Ways to Resolve Them. Vibration or noise in the compressor: Misalignment (failure to align properly). Remove the coupling and let the drive unit operate alone; if the drive unit does not vibrate, the fault may be caused by misalignment. Refer to the relevant sections of the manual to check for misalignment. Check the compressor rotor for imbalance to determine if it is caused by debris; rebalance it if necessary. Inspect the bearings for wear caused by dirty oil, and replace them if necessary. Deflections caused by the stress transmitted from the gas pipelines to the casing (misalignment); fix the pipelines properly to prevent excessive stress on the casing. The pipes should have sufficient elasticity to meet the requirements of thermal expansion. Coupling imbalance: Remove the coupling and check for imbalance. Whether the operating conditions of the surging compressor are outside the surge zone. The foundations of machines located near the compressor should be separated from one another to increase the flexibility of the connecting pipelines. Support bearing failure: Improper lubricating oil – Ensure that the oil used meets the specified requirements. Regularly check whether there is water or dirt in the oil. Check for deviations and adjust as necessary. If the bearing clearance exceeds the specified value, make adjustments where required. Re-align the compressor or coupling if it is unbalanced. In the event of a thrust bearing failure resulting in excessive axial force, ensure that the coupling remains clean; during installation, make sure that the driving machine does not exert too much force on the compressor. Use lubricating oil that meets the specified requirements. Regularly check the oil for water or contaminants. Recheck and realign for deviations and vibrations caused by oil seal ring failures. Check the oil dirt filter; replace the dirty element and check whether the pipes are clean. If the oil seal gap does not conform to the specified values, check the gap and adjust it if necessary. If the oil pressure is insufficient, check the reference air pressure to ensure it is at or above the minimum value. Chapter 8 Inspection Checklist: Inspection Items, Inspection Periods, and Inspection Purposes – During operation, during shutdown; Interval: Half a year, one year, one year or more. 1. Centrifugal compressor: 1. Support and thrust bearings × Inspection for wear and overheating, as well as inspection of the rotor’s axial displacement. 2. Seal ring × Inspection for wear and overheating. 3. Inlet guide vane control servo motor × Replace gaskets. 4. Rotor × Check for scale and corrosion after 3 years. 5. After 3 years, inspect the baffles for scale buildup and signs of corrosion. ×Check of gas labyrinth seal condition × Replace gasket. 6. Housing, end flanges × Check for scale and corrosion after 3 years. ×Inspection of the gas labyrinth seal condition × Descaling of the conduit on the end flange × Inspection. II. Compressor coupling: Inspection items, inspection periods – During operation, during shutdown; intervals: half a year, one year, more than one year. Diaphragm coupling: × Check for any defects such as loose nuts or cracks; × Check for any cracks on the outer surface. For details, refer to the manufacturer’s instructions for installation, use, and maintenance of diaphragm couplings. III. Lubricating oil system: 1. Properties of the oil × Physical–chemical property inspection. 2. Main oil tank × Check the condition of the paint on its walls ； Inspect the bottom of the fuel tank; it should be cleaned every time oil is drained. 3. Pump × Inspection of coupling condition × Cleaning of inlet filter × Energy check of pump × After 3 years, inspect the internal components of the pump. 4. Filter × When the filter pressure drop exceeds the specified value, the filter element must be replaced. × The filter element should be replaced annually, regardless of which component fails first. ×× Is the operation of the oil circuit switching valve smooth? 5. Oil cooler × Is the operation of the oil circuit switching valve smooth? × Inspection for scaling and corrosion on the water side. 6. Safety valve × Set properly. 7. Control valve × Leakage sealing is required when necessary. Perform appropriate operational inspections; after 3 years, inspect the wear of internal components. IV. Pneumatic system 1. Safety valve × Set. 2. Control valve × Leakage sealing when necessary × Appropriate operational checks × After 3 years, inspection of internal component wear. V. Instruments 1. Indicators for pressure, temperature, etc. × × Adjust as needed 2. Transmitters, regulators × Adjust as needed 3. Pressure switches × × Check the alarms; temperature switches × × Check the operation of auxiliary equipment; level switches × × Check the operation of the shutdown mechanism 4. Shutdown control buttons × × Check their operation. Note: When the machine is operating normally, the checks marked with “×” can be carried out at more appropriate times, based on the operator’s experience. Operating Procedures for Turbines – Chapter 1: Technical Parameters
I. Technical Parameters of the Turbine
| Parameter | Unit | Value | Remarks |
|-----------|------|-------|---------|
| Model | – | GN32/01, 2H2200 | Gas-pressurized turbine unit |
| Rotation direction | – | Clockwise when viewed from the turbine toward the syngas compressor | |
| Number of stages | – | – | |
| Rated power | KW | 12,107 | |
| Pressure before the main steam valve | MPa | 8.4, 8.1–8.7 | |
| Main steam temperature | °C | 525, 515–530 | |
| Main steam flow rate | t/h | 36 | |
| Rated main steam flow rate | t/h | 45, 36–45 | |
| Turbine speed (rated) | r/min | 4,485, 3,364–4,709 | |
| First-order critical speed | r/min | 1,425 | |
| Second-order critical speed | r/min | 2,810 | |
| Maximum allowable shaft displacement | mm | ±1.0 | |
| Maximum allowable shaft vibration | – | – | |
| Circulating water temperature | °C | 25 | |
II. Parameters Related to the Oil System
| Parameter | Unit | Value | Remarks |
|-----------|------|-------|---------|
| Oil pressure at the inlet of the oil pump in the oil station | MPa | Atmospheric pressure; highest liquid level indicated | |
| Oil pressure at the outlet of the oil pump in the oil station | MPa | 0.25 | |
| Oil filling volume for the oil tank | m³ | 12.1 | |
| Oil cooling water volume | m³/h | 70 | |
| Nominal volume of the oil tank | m³ | 13 | |
| Lubricating oil temperature | °C | 45–65 | |
| Oil flow rate at the inlet of the oil pump in the oil station | m³/h | 37.524 | |
| Highest oil level | m | 1.884 | |
| Lowest oil level | m | 1.332 | |
| Oil output volume | m³/h | 74.01 | |
| Oil output pressure | MPa | 1.2 | |
II. Technical Parameters of the Control System
Chapter 2: Preparation for Starting the GN32/01 Unit
Section 1: Preparations Before Starting
1. Preparations for starting: The turbine is a power device that operates at high speeds under high temperatures and pressures. It is a complex whole composed of many parts and components. Therefore, proper operating procedures for startup, operation, and shutdown must be established. In addition, based on the characteristics of this steam turbine, certain requirements that must be adhered to are proposed. The detailed steps and methods shall be strictly followed in accordance with the operating procedures for steam turbine units. 1.1 Before startup, thorough and rigorous inspection must be carried out: check that the steam-water system, oil system, and drain system are functioning normally ； Check that all instrument measurement points are correct and functioning properly ； Check that all components are intact, and that the moving parts operate smoothly without any sticking. All fastening screws are tightened. Operate the barring gear and listen carefully to ensure there is no friction or abnormal noises ； Check that the condensing system is in a normal state ； Check that the speed control system is in the correct position, and that the emergency shutdown throttle is in the disengaged position. 1.2 Inspection of the main oil system: Before starting the turbine, it is necessary to circulate oil in the oil system first; when performing this oil circulation, the filter elements of the oil filter must be removed and replaced with temporary filters ； The oil inspection standards must comply with the domestic N46 turbine oil standards ； Its quality shall not be lower than the Class B requirements specified in standard GB11120-2011 ； The oil circulation must pass inspection by a laboratory technician before it can be put into use ； The cold oil coolers are operating properly; one is in use while the other is on standby. 1.3 Inspection of the main steam system: All components and parts operate smoothly, the connections are tight, the insulation is in good condition, and the drain systems function properly, meeting the requirements of the production process. 1.4 Inspect the circulating water system by opening the inlet and outlet doors of the cooling water for the cold oil cooler. 1.5 Inspection of the condensate water system: The inlet and outlet valves of the condensate pump, as well as the air valve and seal water valve, should be open; the check valve should be airtight, and the interlock tests should proceed normally. Close the outlet drain valve. 1.6 Upon receiving the command to start the turbine, all necessary preparations must be made, the equipment and systems in charge of should be thoroughly inspected, and contact should be established with the relevant departments: The electrical staff are responsible for measuring the insulation of each motor and ensuring that the power supply is available ； Thermal engineering: Connect all instruments and signal power supplies, and check that the audible and visual signals are normal ； Open the primary and secondary valves of all pressure gauges fully, and place thermometers at each bearing ； Chemical technician: Prepare demineralized water and monitor the level changes in the flasher ； Boiler room: Prepare for supplying high-pressure steam externally ； Section 2: Heating the Pipes and Removing Water Vapor 1.1 Heating the pipes and removing water vapor: Slightly open the isolation valve to maintain the pressure inside the pipes at around 0.25 MPa, then heat the pipes at a rate of 5–10°C per minute ； The temperature of the inner wall of the tube reaches 130–140°C, and the pressure inside the tube is increased at a rate of 0.25 MPa/min until it reaches the specified value. At the beginning of pipe warming, the drain valve should be kept wide open to allow condensate to be discharged promptly; as the temperature of the pipe walls and the pressure inside the pipe increase, the drain valve should be gradually closed to prevent large amounts of steam from escaping. Be careful when warming the pipes! It is essential to strictly prevent steam from leaking into the cylinder and causing deformation of the rotor ； The temperature of each part of the pipeline must not be lower than the saturation temperature at the corresponding pressure. 1.2 Prepare all turbine startup tools, record books, vibration meters, and fire-fighting equipment ； Fill out the turbine startup operation ticket ； Section 3: Starting of Auxiliary Equipment 1 Starting 1.1 Start the jacking oil pump and activate the turning gear; maintain the turning operation and listen for any signs of friction ； 1.2 Start the lubricating oil pump to remove air from the oil pipelines and various components under low pressure ； Install the turning gear. 1.3 Start the circulation system; be careful to open the outlet disc valve slowly while filling the air cooler with water, and once it is fully filled, gradually open the outlet disc valve completely. Open the steam valve of the startup vacuum pump, then open the air valve of the same pump; adjust the opening degree of the steam valve to maintain a vacuum level in the condenser above 30 KPa ； When the vacuum (absolute value) of the turbine air cooler reaches 0.04 MPa, start the main exhaust pump and stop the startup exhaust pump ； 1.4 Before starting up, a heat source should be provided to the air cooler through a temperature-reducing pressure regulator. When the ambient temperature is below 2°C, all columns that can be isolated by the air cooler must be isolated, in order to ensure its proper operation and prevent freezing blockages. Supplement the air cooler with softened water to maintain a high level in the hot water well, thereby providing an adequate water supply for the steam ejector. 1.5 Startup: (Manual startup) When the machine is stopped, the start valve is in a position that connects the oil circuit to the return path, and thus no starting oil can be established. At startup, rotate the start valve (1839) clockwise to establish start oil pressure. Once the starting oil is established, rotate the handwheel of the shut-off valve (1830) counterclockwise to establish the quick-shut oil. After the quick-shut oil is established, slowly rotate the start valve (1839) counterclockwise to connect the start oil to the return oil and send it to the tank. The speed control system is allowed to impulse the turbine only after the quick-shut valve is fully open. 1.6 Low-speed Warm-up ； After the pipe warming and drainage are completed, close the drainage valve, start the turbine, and gradually carry out low-speed warming by maintaining a speed of 200 r/min for no less than 30 minutes. As the speed approaches the critical speed, accelerate steadily to pass through the critical region; once the speed reaches the lower limit set for control, the acceleration process ends and the turbine enters the controlled operation range. At this point, the set speed can be adjusted to the rated value as needed. Monitor to ensure that the temperature difference between the upper and lower cylinders is no more than 50°C (according to relevant data), keep an eye on the thermal expansion values, and ensure that the axial displacement remains within 0.6 mm. After checking the above system equipment and confirming they are functioning properly, preparations for the next stage are carried out. Section 4: Ramping Up Operation 1.1 The following conditions must be met prior to ramping up operation: 1.1.1 The temperature of the lubricating oil should be no lower than 35°C, and the oil pressure in the main lubricating oil pipeline should be around 0.25 MPa ； The oil pressure at the inlets of each bearing of the turbine is 0.1~0.12 MPa, while the oil pressure for the other bearings is 0.15 MPa. 1.1.2 The main steam pressure is 8.3 MPa, the main steam temperature is above 525°C, the vacuum level is -0.06 MPa, with a minimum value of not less than -0.053 MPa. 1.2 Inform personnel in relevant positions that the turbine is to be started up. 1.2.1 The operator opens the steam inlet valve of the turbine and informs the on-site operators to close their bypass valves ； At startup, rotate the start valve (1839) clockwise to establish start oil pressure. Once the starting oil is established, rotate the handwheel of the shut-off valve (1830) counterclockwise to establish the quick-shut oil. After the quick-shut oil is established, slowly rotate the start valve (1839) counterclockwise to connect the start oil to the return oil and send it to the tank. The speed control system is allowed to impulse the turbine only after the quick-shut valve is fully open. 1.2.2 Inform the on-site operators to reset the emergency safety device, check and confirm that the emergency shutdown indicator shows “normal”, then click the “Latch” button on the speed control screen to establish the safety oil pressure. 1.2.3 The operator clicks “Enter Speed Setting” under mode selection; for a cold start, enter a warm-up speed of 800 rpm, with an increase rate set at 5 r/min ； In the case of a hot start, enter a warm-up speed of 1125 rpm and set the acceleration rate to 10 r/min. Click Confirm, then click “Proceed”; the turbine’s control valves will open automatically, and the turbine will start up with a surge ； 1.2.4 Listen for any abnormal noises inside, check the oil temperature of the bearings and the temperature of the bearing shells, as well as ensure that the expansion and axial displacement of the unit are within normal limits ； 1.2.5 Once everything is normal, start increasing the speed ； 1.2.6 Acceleration procedure: Refer to the startup time schedule – Cold-start time schedule. Time for reaching startup speed: Accelerate to 800 r/min in 3 minutes; maintain 800 r/min for >60 minutes. Then accelerate evenly to 1125 r/min in 1 minute, and further accelerate evenly to 2200 r/min (rapidly passing through the critical point) in 0.5 minutes. Adjust the speed to 2510 r/min in 0.5 minutes, then accelerate evenly to 3110 r/min (rapidly passing through the critical point) in 0.5 minutes. Finally, accelerate evenly to 3384 r/min (within the speed adjustment range of 3884–4709) in 0.5 minutes. Total time: >66 minutes. 1.3 Precautions during the startup process: 1.3.1 During acceleration, inform the on-site inspectors to check whether there are any abnormal noises in the turbine’s vibration. If such noises are detected, the acceleration process must be stopped immediately; the cause must be identified, and normal operation restored before resuming acceleration ； 1.3.2 During the speed-up process, notify the on-site inspection personnel to monitor changes in the turbine exhaust pressure and oil pressure; if any abnormalities are detected, the speed-up should be stopped immediately, and it can resume only after the issues are resolved ； 1.3.3 During the acceleration process below 1125 r/min, the vibration of the unit must not exceed 0.03 mm; if this value is exceeded, the speed should be reduced until the vibration ceases. The unit should then operate at this reduced speed for 30 minutes before attempting to increase the speed again. If the vibration still persists, the speed must be reduced further to 800 r/min and the unit operated at that speed for 60 minutes before trying to increase the speed once more. If the vibration remains uncontrolled, the unit must be shut down for inspection (the vibration level must not exceed 0.1 mm when passing through the critical speed) ； 1.3.4 Always monitor cylinder expansion to prevent abnormalities in the slider system ； 1.3.5 Adjust the condensate recirculation in a timely manner to maintain the water level in the air coolers; when the condensate quality is unsatisfactory, it is discharged into the drain, and once its quality becomes satisfactory, it is recycled back into the system ； Cooling water is introduced when the oil temperature in the oil cooler exceeds 40°C. 1.3.6 When the speed reaches 3384 r/min, the speed-up process is completed; the on-site inspection personnel are notified to conduct a thorough check of the turbine to ensure there are no abnormalities ； Section 5 Principles of Hot Start 1.1 Whenever the downtime is within 12 hours, restarting the unit is considered a hot start; in all other cases, it is considered a cold start. 1.2 For hot starts, the following points shall be observed: 1.2.1 The steam temperature should be 50–100°C higher than the cylinder temperature, with a superheat of 50°C ； 1.2.2 The rotor should be in a state of continuous barring 4 hours before startup ； 1.2.3 During continuous barring operation, steam should be supplied to the shaft seal first, and then a vacuum should be created ； 1.2.4 The pipes must be thoroughly warmed up and drained of water before startup ； 1.2.5 The preparatory work before startup is carried out in the same manner as normal startup ； 1.2.6 During hot start-up, bearing vibration must be closely monitored; if the vibration increases significantly, the machine should be stopped immediately. After identifying the cause, a decision can then be made as to whether to attempt to restart it. 1.3 Time allocation for hot start-up of the steam turbine
Time allocation for hot start-up:
Time required to reach starting speed: It takes 2 minutes to accelerate from standstill to 1125 r/min.
Maintain a speed of 1125 r/min for 5 minutes for inspection purposes.
It takes 0.5 minutes to uniformly accelerate to 2200 r/min (the critical point between 3400 and 4700 r/min is quickly passed).
Maintain a speed of 2200 r/min for 2 minutes for further inspection.
It takes 0.5 minutes to uniformly accelerate to 2510 r/min.
It takes 0.5 minutes to uniformly accelerate to 3110 r/min (the critical point between 2510 and 3110 r/min is quickly passed).
It takes 0.5 minutes to uniformly accelerate to 3384 r/min.
Total time required: 11 minutes.
Chapter 3: Operation and Maintenance
Section 1: Normal operating control parameters
| Parameter | Value Range | Unit | Remarks |
|-----------|-------------|------|---------|
| Rated power | 12,107 kW | kW | |
| Steam turbine speed | 4485 r/min | r/min | |
| Main steam pressure | 8.4 MPa | MPa | Range: 8.1–8.7 MPa |
| Main steam temperature | 525 °C | °C | Range: 515–530 °C |
| Main steam flow rate | 36 t/h | t/h | Range: 34.81–44.56 t/h |
| Exhaust steam pressure | 0.02 MPa | MPa | |
| Governor oil flow rate | 150 L/min | L/min | Instantaneous value; average value: 470 L/min |
| Lubricating oil temperature | 45–65 °C | °C | |
| Lubricating oil flow rate | 320 L/min | L/min | |
| Maximum temperature of thrust bearing pads | 100 °C | °C | |
| Maximum temperature of bearing return oil | 75 °C | °C | |
| Bearing vibration level | < 0.05 mm | mm | |
| Oil level in the tank | Two-thirds full | | |
| Axial displacement | > -0.7 | | | ； ＜+1.3mm; air cooler vacuum: -0.06 MPa; supercooling degree of condensate water: ＜2℃. Section 2: Maintenance and Inspection During Operation 1.1 The duty personnel must monitor the systems carefully, conduct timely comparative analyses based on the operation status of the unit and changes in the instruments, so as to ensure that the equipment under their responsibility operates under safe and economical conditions. 1.2 In accordance with the routine inspection system, comprehensive inspections of the equipment and systems under supervision are carried out on a regular basis, including checks on sound, vibration, temperature, pressure, oil flow, the temperature of each bearing, oil level in the tank, as well as the tightness of the steam, water, and oil systems. Measures must be taken to prevent fires, and the water seal in the vacuum system must not run out of water. 1.3 Take readings on time; if there is a discrepancy between the instrument readings and the normal values, the cause should be identified immediately and necessary actions taken. 1.4 When the load of the unit changes, the following points should be noted: ensure that there are no issues with the control system; if such issues occur, adjust the electrical load back to its original operating condition, identify the cause, and take appropriate measures ； Check the changes in key instruments such as axial displacement, thrust bearing temperature, main steam parameters, vacuum, condensate pressure, and flow rate ； Listen to the sounds inside the turbine and check the unit’s vibration ； Pay attention to the oil temperature in the cold oil cooler; it should be adjusted promptly if it exceeds the allowable range, as large fluctuations in oil temperature must be avoided ； 1.5 During operation, analyze the conditions of steam and water as well as oil quality in accordance with chemical supervision requirements, and address any issues identified promptly. 1.6 Maintain the optimal vacuum level in the air cooler; properly start/stop and adjust the circulating water volume. Regularly analyze the operating indicators of air coolers to maintain their economical operation. Make sure to check the standby status of each backup pump; it should meet the requirements prior to startup. The regular switching and testing of equipment are carried out as stipulated. 1.7 Any equipment defects detected during operation should be reported to the shift supervisor promptly, and a record of the equipment defects should be filled out. 1.8 Ensure civilized production by thoroughly cleaning the equipment and floors under one’s responsibility once per shift. Chapter 4: Shutdown of the Turbine Section 1: Preparations before Shutdown 1.1 Upon receiving the order from the shift supervisor to shut down the turbine, the operator first fills out the operation ticket, and then carries out the preparatory work for shutdown under the unified supervision of the shift supervisor. 1.2 Test the oil pump and turning motor ； 1.3 Contact personnel in various positions at the site. During load reduction, pay attention to making timely adjustments ； Use condensate recirculation to maintain the level of the air cooler, as well as the current and pressure of the condensate pump, and adjust the oil temperature of the oil cooler in a timely manner. Before 1.4, the instantaneous fluctuation amplitude of the cylinder wall temperature shall not exceed 20°C, and the overall amplitude shall not exceed 50°C. 1.5 Pay attention to the expansion of the cylinder and the vibration of the unit. 1.6 Pay attention to the operation of the speed control system; it should not have any setting obstacles or sticking issues. Section 2: Shutdown 1.1 Notify the control room and boiler room to make preparations for shutdown. 1.2 Shutdown can only be carried out by gradually reducing the load, with the load reduction rate not exceeding 100 KW/min. 1.3 Manually operate the emergency cut-off throttle to close the quick-shut valve. 1.4 Record the coasting time – when the rotational speed reaches 0 and the vacuum level also reaches 0, record that coasting time. 1.5 Close the isolation valve on the main steam pipe. Open the drain valves for the cylinder and main steam pipe, etc., reduce the speed to 0 at 1.6, and immediately start the barring gear. 1.7 Stop the condensate pump and close the recirculation valve. 1.8 Open the main steam pipeline drain, as well as the main steam valve drain and the vessel drain. 1.9 Stop the operation of the air cooler when the temperature of the 1.9 exhaust cylinders is below 50°C. After 2.0 stops cranking, all oil pumps can then be shut down. 2.1 Shutdown: (Manual shutdown) Turn the shut-off valve clockwise to reduce the quick-closing oil pressure; under the action of spring force, it will close rapidly. Section 3: Use of the barring gear
1.1 The interlock protection for the barring gear must be activated during operation. 1.2 Perform continuous or intermittent turning of the shaft after shutdown. 1.3 Intermittent cranking: The rotor is turned 15 degrees every 15 seconds. 1.4 Stop the turning gear once the temperatures of the upper and lower cylinder walls drop below 50°C. 1. Cranking: Maintain the bearing oil supply pressure at no less than the specified value. 1.6 Eight hours after the turning gear stops, the oil pump ceases to operate, and the range hood is also turned off. Chapter 5: Startup and Shutdown of Auxiliary Equipment
Section 1: Technical Parameters of Auxiliary Equipment
I. Condensate Pumps
Model: ESH25-315 (two units)
Flow rate (m³/h): 5
Medium: Steam, condensate
Head (m): 30
Rotation speed (r/min): 1475
Bearings: BB2
Motor model: YB3-132S-4WF1 (two units)
Motor voltage (V): 380
Motor power (kW): 5.5 kW
Rotation speed (r/min): 1440
II. Drain Pumps
Model: ESH50-315 (two units)
Flow rate (m³/h): 45.73
Medium: Steam, condensate
Head (m): 100
Rotation speed (r/min): 2950
Bearings: BB3
Motor model: YB3-200L2-2WF1 (two units)
Motor voltage (V): 380
Motor power (kW): 37 kW
Rotation speed (r/min): 2958
Bearings: 6312
III. Oil Station Pumps
Model: NSNH1300-46 (two units)
Flow rate (m³/h): 1234
Shaft power (kW): 37 kW
Rotation speed (r/min): 1450
Motor model: YB225S－4－B3 (two units)
Motor voltage (V): 380
Motor power (kW): 37 kW
Motor rotation speed (r/min): 1472
Motor current (A): 69.9
Frequency (Hz): 50
Model: NSNH/C440-54
Flow rate (L/min): 560
Shaft power (kW): 7.5
Rotation speed (r/min): 1450
Motor model: YB132M－4－B3
Motor voltage (V): 380
Motor power (kW): 7.5
Motor rotation speed (r/min): 1450
Motor current (A): 15.48
Frequency (Hz): 50
IV. Oil Coolers
Model: …
Oil pressure (MPa): 1.6
Cooling area (m²): 76 (two units)
Water pressure (MPa): 0.9
Oil temperature (°C): 60
Water temperature (°C): 50
V. Air Coolers
Model: N-560-6
Net weight (kg): 6283
Cooling area (m³): …
Shell-side pressure (MPa): 0.5
Cooling water temperature (°C): 110
Tube-side pressure (MPa): 0.65
VI. Steam Jet Pumps
Model: C-2620-14588
Steam pressure (MPa): 2.5
Cooling area (m²): 15/7.5
Steam temperature (°C): 300
Steam consumption (kg/h): 150
Steam exhausted amount (kg/h): 20.4
Shell-side set/test pressure (MPa): 0.2/0.4
Tube-side set/test pressure (MPa): 1.2/1.6
Section 2: Condensate Pumps
I. Preparations before startup:
1. Before starting, it is necessary to inspect the pump and motor (including turning the shaft and checking the grounding wires). The condensate system should also be inspected; the inlet and outlet valves, air valves, and seal water valves of the condensate pumps should be open, while the check valves should be tight. The interlocking tests should proceed normally. Close the outlet drain valve. 2. The interlock should be in the stopped position ； 3. Close the condensate pump outlet valve (during trial operation) ； 4. Open the water seal door of the condensate pump ； 5. Open the air valve of the condensate pump (pay attention to changes in the vacuum level of the air cooler when opening it after maintenance) ； 6. Open the inlet valve of the condensate pump ； II. Startup: 1. Close the operation switch of the condensate pump and check that the pump operates under no-load conditions normally ； 2. Check the sound; vibration should be normal ； 3. Open the outlet valve of the condensate pump ； 4. Adjust the recirculation flow based on the air cooler water level to maintain normal pressure and current of the condensate pump ； 5. During the startup of the turbine, close attention should be paid to maintaining the condensate header pressure at a constant level ； 6. The outlet valves of the standby condensate pumps during operation should be fully open, and the number of operating condensate pumps should be adjusted according to the load and condensate flow rate ； 7. Activate the interlock for the condensate pump ； III. Stop: 1. Interlock disconnection of the condensate pump ； 2. Close the condensate pump outlet valve ； 3. The current should drop to zero when the start button of the condensate pump is pressed ； 4. Pay attention to the coasting condition (be careful not to reverse) ； 5. If this pump is to be used as a standby unit, the outlet valve should be opened and the interlock should be set to the active position. IV. After the change of the condensate pump, the chemical staff should be notified promptly to test the oxygen content in the condensate. If this level increases, the cause must be identified and eliminated. When the plant is shut down and the condensate pump stops, close attention should be paid to the water level in the air coolers to prevent them from filling up due to the check valve getting stuck after the condensate pump stops. Section 3: Steam Extractor 1. Activating the steam extractor unit: 1.1 Open the steam valve for starting the steam extractor, then open the air valve for it; adjust the opening degree of the steam valve so that the vacuum level in the condenser remains above 30 KPa ； 1.2 When the vacuum (absolute value) of the turbine air cooler reaches 0.04 MPa, start the main exhaust pump and stop the startup exhaust pump ； Note: When starting the main exhaust pump, start the secondary stage first, then the primary stage ； Open the steam valve first, then the air valve. When stopping or starting the vacuum pump, close the air valve first, then the steam valve. 2. Switching of the main exhaust unit 2.1 When switching the exhaust units, the secondary unit should be switched first, followed by the primary unit ； 2.2 When switching the extractor unit, the steam valve should be opened first, followed by the air valve ； 2.3 During the switching process, pay close attention to the vacuum level of the condenser; if a high vacuum level cannot be maintained after the switch, the original ejector operation mode should be restored. Section 5: Fuel Tank and Fuel Pump I. Preparations before startup 1. Both the fuel pump and the motor must be able to operate properly ； 2. The oil pump interlock is in the off position ； 3. Close the oil pump outlet valve ； 4. Open the oil pump inlet door ； II. Startup: 1. Close the oil pump switch and check that operation under no-load conditions is normal ； 2. Check that the sound and vibration are all normal ； 3. Slowly open the outlet door and check that operation under load should be normal ； 4. Implement interlocks as needed ； III. Stop: 1. The oil pump interlock is set to the off position ； 2. Click the oil pump stop button; the current should drop to zero ； Section 6: Air Coolers I – Starting the air blower: When increasing the pressure and temperature inside the pipe, it should be done gradually step by step to avoid damaging the equipment due to sudden heating shocks ； During normal operation of the 2 air coolers, the fans should be started first, followed by the introduction of the medium into the tube bundle. When shutting down, the supply of medium to the tube bundle should be stopped first, and then the fans should be turned off ； For the operation of 3 easily solidifiable media in winter, the procedure is the opposite of that for 2 ； When starting an air cooler that operates under negative pressure, the vacuum pump should be turned on first; once the specified vacuum level is achieved inside the tubes, the fan should be started, and then the medium relevant to the operation should be introduced into the tubes. To shut down the device, the process should be reversed. When operating in winter, after the vacuum pump has been used to achieve the specified vacuum level, the medium should be introduced into the tubes first, followed by starting the fan, in order to prevent the tubes from freezing up and preventing the device from functioning ； 5. When stopping, use low-pressure steam to purge and remove condensate to prevent freezing and corrosion ； 6 Before starting the machine, the set screws at both ends of the floating tube box should be removed to ensure that the floating tube box can move freely during operation, thereby compensating for the thermal expansion and contraction of the finned tubes. 7 Before starting up, a temperature-reducing pressure regulator should be used to provide a heat source for the air cooler. When the ambient temperature is below 2°C, all columns that can be isolated by the air cooler must be isolated, in order to ensure its proper operation and prevent freezing blockages. Before starting up, a temperature-reducing pressure regulator should be used to provide a heat source for the air cooler. (II) Precautions for operating the fan of the air cooler: 1. The angle of the fan blades should be set according to the data provided in the design; increasing this angle excessively will cause the motor to operate under overload conditions. 2. It is necessary to closely monitor the motor current during operation, especially when a large volume of air is being handled. Section 7: Oil Coolers I. Switching of oil coolers during operation: 1. To start, switch, or stop an oil cooler while it is in operation, an operation ticket must be filled out first, and the operation can only be carried out under the supervision of the shift supervisor. 2. The steps for switching the cold oil cooler are as follows: (1) Check that the outlet valve of the standby cold oil cooler is in the open position ； (2) Check that the inlet valve of the standby cold oil cooler is in the closed position ； (3) Check that the throttle at the inlet of the backup cold oil cooler is in the open position ； (4) Check that the throttle at the outlet of the backup cold oil cooler is in the closed position ； (5) Open the cooler to the oil tank vent valve and verify that the standby cooler is indeed filled with oil ； (6) Contact the main operator to carry out the switching of the oil cooler; the main operator should pay close attention to changes in oil pressure and temperature ； (7) Slightly increase the throttle at the outlet of the standby cold oil cooler ； (8) Due to the low oil temperature in the standby cold oil cooler, mixing with this oil results in a decrease in bearing temperature; it is necessary to adjust the inlet valve of the operating cold oil cooler to maintain the oil temperature between 38 and 42℃ ； (9) Slowly open the throttle at the outlet of the newly installed cold oil cooler, and adjust the cooling water based on the oil temperature at the outlet of the cold oil cooler. (10) Confirm that the standby cold oil cooler is fully operational and working properly before shutting down the cold oil cooler that needs to be stopped; slowly close its outlet oil valve and inlet water valve. 3. When introducing a cold oil cooler that has been overhauled into operation, it is necessary to fill the cooler with oil very carefully and slowly, removing all air from the oil side, to prevent any fluctuations in the oil system. 4. If one of the cold oil coolers needs to be shut down during operation, its outlet oil valve and inlet water valve should be closed slowly to maintain the oil temperature between 38~42°C. II. When the oil temperature rises due to high circulating water temperature, the standby cold oil cooler should be activated promptly. Chapter 6 Turbine Testing Items Section 1 Testing Items Before Turbine Startup 1. Low oil pressure protection trip test ； 2. Low vacuum protection trip test ； 3. Axial displacement protection ； 4. Emergency button test (mechanical-electrical interlock) ； 5. Manual emergency safety device test ； 6. Thermal signal testing ； 7. Over-speed protection test ； 8. Quick-break valve shutdown test ； 9. Automatic start-stop test of the condensate pump ； Section 2: Test items after the turbine reaches its rated speed 1. Sealing test of the main steam valve ； 2. Throttling valve tightness test ； 3. Emergency safety device overspeed test ； Section 3: Test Methods for Major Test Items – Automatic Startup of Low-Pressure Oil Pump I. Test Conditions: 1. The oil system has been filtered, and the filter screen at the inlet of the main bearings has been removed ； 2. Check that the oil pump is in standby mode, and the automatic start switch is disabled ； 3. Conduct the test before warming up the main steam pipes ； II. Testing Methods: 1. Start the oil pump to check that the oil pressure is normal; move the automatic switch from the manual position to the automatic position ； 2. Stop the oil pump; it should restart automatically when the lubricating oil pressure drops to 0.19 Mpa ； ； 3. Continue to reduce the oil pressure; when the lubricating oil pressure drops to 0.10 Mpa, close the valve immediately, shut down the speed control valve, and send a signal ； 4. When the lubricating oil pressure drops to 0.08 Mpa, the turning gear should stop functioning ； 5. Restore the oil pressure in the oil system after the test. Section 4: Sealing Test of the Main Steam Valve I. Test Conditions: 1. When the turbine is installed for the first time or after major repairs ； 2. The main steam valve tightness test start button is pressed and in automatic mode ； II. Test method: 1. On the overspeed test screen, click the “Start main steam valve tightness test” button; once this test is initiated, the valve motor will rotate in reverse direction ； 2. With the main steam valve closed and all control valves open, let the turbine run idly, and observe whether the speed drops below 1000 revolutions per minute ； 3. After the test is completed, click the “Main Steam Valve Sealing Test Reset” button to exit the main steam valve sealing test. Section 5: Fuel Injection Test To ensure that the emergency shutdown hammer can quickly move out to shut down the turbine in the event of overspeed, it is necessary to conduct regular tests on the movement of this hammer. This experimental activity involves spraying oil into the flyweight to increase the centrifugal force, causing it to fly out. But the fly hammer should not be braked due to the fuel injection test. Section 6: Over-speed protection testing After the first installation of a turbine or following major repairs, it is necessary to verify the accuracy of the operation of the over-speed protection systems; testing must be conducted for each type of such protection system. 1.1 103% overspeed test: On the overspeed test screen, click the “103% Overspeed” button while in the disconnection mode. When the actual rotational speed exceeds 3490 rpm, the 103% overspeed protection activates, and the target rotational speed is automatically set to 3485 rpm, until the actual speed drops to this target value. 1.2 The 110% overspeed test: On the protection switching screen, set the turbine overspeed protection switch to the on position, then click the “110% Overspeed” button. The target speed value will be automatically set to 3722 rpm. When the actual speed exceeds 3485 rpm, the 103% overspeed protection should not activate; however, when the actual speed exceeds 3727 rpm, a signal is sent to activate the 110% overspeed protection, causing the machine to stop until its speed drops to the target value. 1.3 Mechanical overspeed test: Switch the overspeed protection toggle switch on the cabinet to the right to increase the set value of the overspeed protection component to 3790 rpm. By clicking the “Mechanical Overspeed” button, the speed setting is automatically adjusted to 3793 rpm. When the actual speed exceeds 3490 rpm, the 103% overspeed protection should not activate; when the actual speed exceeds 3722 rpm, the 110% overspeed protection should also not activate. Once the actual speed exceeds 3790 rpm, the emergency shut-off device shall activate, causing the main steam valve and control valves to close, thereby causing the speed to start decreasing. When conducting this test, an operator must be on site to monitor the rotational speed and the operation of the emergency shutdown device. V. Reset: On the overspeed test screen, by clicking the “Reset” button, the ongoing overspeed protection test can be stopped, and the system can be restored to its state before the test began. Section 7 Vacuum Tightness Test I. Test Conditions; 1. Maintain stable unit load ； 2. The load should be no less than 80%. II. Testing method: 1. Keep test records as specified in the table ； 2. Close the steam valve that supplies low and medium pressure steam to the air cooler ； 3. During the 5-minute test, record the vacuum value once per minute; a value not exceeding 4 mmHg per minute on average is considered acceptable ； 4. After the test, open the steam valve from low-pressure steam to the air cooler ； III. Precautions during the test: 1. If the vacuum decreases too rapidly during the test, the test should be stopped to determine the cause ； Chapter 7 Provisions on Special Procedures
1.1 For the maintenance of equipment, safety measures must be implemented in accordance with safety regulations. All doors that are isolated from the operating system must be securely fastened, locked, and marked with a “Do Not Operate” sign to prevent accidental operation, which could lead to steam, water, or oil leaks. 1.2 Regulations regarding the timing of record-keeping during startup and shutdown: 1.2.1 Turbine startup records: (1) Before warming up the main steam pipe ； (2) Before the impulsive rotor ； (3) After warming up at 1125 revolutions per minute is completed ； (4) After warming up at 2200 revolutions per minute is complete ； (5) After warming up at 3110 revolutions per minute is completed ； (6) After the warm-up at 3384 rpm is completed ； (7) After reaching the set speed ； 1.2.2 Turbine shutdown record: Generate a rotor coastdown curve, and record the speed every minute after the brake is applied.