Thermal scheme of the turbine T-25-29

Contents

CONTENTS

INTRODUCTION

1 CHARACTERISTICS OF STEAM TURBINE PLANT

1.1 Basic Technical Data

1.2 M turbine oil supply

1.3 Turbine Control System

1.4 Protective devices and actuation setpoints

1.5 Condensing unit

1.6 Preheater

2 START-UP OF STEAM TURBINE T-25-

2.1 Preparation for turbine start-up

2.2 Heating of superheated steam line and steam box

2.3 Turbine rotor push

2.4 Switching the turbine into the network

2.5 Parameters at which turbine start-up is prohibited

3 TURBINE MAINTENANCE DURING OPERATION

3.1 Maintenance of oil supply system

3.2 Condensing plant maintenance

3.3 Operation of regenerative heaters

3.4 Maintenance of the control system

3.5 Generator and exciter maintenance

4 ACTIONS IN EMERGENCY SITUATIONS

4.1 Turbine emergency shutdown

4.2 Actions in case of deviation from nominal steam parameters

4.3 Actions at vacuum drop in condenser

5 TURBINE SHUTDOWN

6 OCCUPATIONAL SAFETY DURING TURBINE MAINTENANCE

7 THERMAL CALCULATION OF HPC FLOW

CONCLUSION

LIST OF LITERATURE

Introduction

Currently, along with new generation power plants, thermal and electric power plants are used to provide consumers with thermal and electric energy, which were commissioned in the first half of the 20th century.

The cost of electricity and heat at many CHPs, especially those equipped with outdated equipment, is high, and their implementation at high tariffs is difficult. Currently, it is important for working CHPs to ensure competitiveness, which is achieved, inter alia, through the optimization of the operating modes of the CHP equipment.

To date, the developed methods for optimizing the operation and control modes of the CHP equipment do not sufficiently take into account the actual state associated with the obsolescence and moral wear of the main and auxiliary equipment .

The purpose of the diploma project is to define the principles of reliable, economical, safe operation of turbine T2529.

Tasks:

- determine technical characteristics of turbine plant equipment;

- study the methods of turbine unit maintenance;

- consider possible emergency situations with the turbine unit;

- study the rules of labor protection during turbine maintenance.

Proper operation of the turbine plant is possible only if the operating personnel is fully aware of the phenomena occurring in the turbine under various operating conditions, is well aware of the design of the serviced unit and accurately and consciously complies with its maintenance instructions. Each steam turbine has its own individual features. Therefore, in no case should it be assumed that all turbines are the same and that, knowing one turbine, you can go to another without any preliminary preparation, even

of the same type, a car.

Serving the turbine generator, we must not forget that you are dealing with a machine, the cost of which is expressed in millions of rubles and the failure of which can cause huge losses, causing a simple industrial enterprise and stopping the supply of energy to entire areas and even the city.

Therefore, any ill-conceived experiments on the turbine being serviced, such as overloading, changing the nominal parameters of steam or gaps in the flow part, are completely unacceptable.

1 characteristic of steam turbine unit t- 25-29

1.1 Basic Technical Data

Turbine T2529 is a two-cylinder machine.

High-pressure cylinder consists of twenty-one active stages, low-pressure cylinder consists of five active stages.

High pressure cylinder (up to sixteenth stage) - steel; the rest of the high pressure cylinder and the entire low pressure cylinder are cast iron.

Disks are fitted directly on rotor in hot state.

The blades in the first fifteen stages have a T-shaped fit, and in the rest - riveted to the disks.

High pressure cylinder diaphragms - steel with set milled nozzles. The diaphragms of the low pressure cylinder are cast iron with poured blades.

Turbine has throttle steam distribution with two overload bypass valves.

Heating turbine of T-25-29 type:

- turbine capacity 25 MW;

- speed of 3000 rpm;

- superheated steam pressure upstream the stop valve - 2.9 MPa;

- condenser pressure - 0.004 MPa;

- superheated steam temperature - 400 ° С;

- steam flow per turbine - 170 t/h;

- number of cylinders - two;

- high pressure cylinder (HPC) with twenty-one pressure stages;

- low pressure cylinder (LPC) with five pressure stages.

The turbine has three steam bleeds:

- first from the fifteenth stage to the high-pressure heater with

steam pressure of 0.7 MPa and steam flow rate of 15 t/h;

- the second stage from the twenty-first stage, adjustable, for heating and deaerator tanks (DB) with a pressure of 0.12 MPa and a steam flow rate of 100 t/h;

- the third stage from the twenty-fourth stage to low pressure heaters (LPA) with a steam pressure of 0.0025 MPa and a steam flow rate of 5 t/h.

Permissible pressure in the control stage is 2.4 MPa.

Connection of high pressure rotor (HPR) and low pressure rotor (LPR) - flexible spring coupling.

Low pressure rotor and generator rotor (WG) - semi-flexible coupling.

The critical number of HPR revolutions is 4060 rpm.

The critical number of LPR revolutions is 4590 rpm.

Throttle control with two reloading valves.

Rotor run-down time - 21 min.

Time of oil drain to emergency oil tank is 9 min.

The volume of the oil tank is 5.5 m3.

The turbine can operate as a purely condensing turbine. In this case, steam flow to the turbine shall not exceed 125 t/h according to the operating condition of the HPR thrust bearing.

Turbine operation for exhaust to atmosphere is prohibited.

With a load of 15 to 20 MW and a sampling steam flow rate of 0.12 MPa from 40 to 70 t/h, the turbine has the highest efficiency (efficiency).

Turbine T2529 is a reserve for water heating for chemical water treatment, for which the circulation water scheme is changed and the turbine is allowed to operate at a deteriorated vacuum with an increase in the temperature of the LPC exhaust pipe to 60 ° С.

Permissible temperature of LPC exhaust nozzle is 55 ° С.

1.2 Turbine oil supply

The turbine has four electrically driven oil pumps: two main oil pumps (GMN1, GMN-2), a backup oil pump (RMN) and an emergency oil pump (AMN).

Pumps are controlled from a panel installed at the turbine driver's workplace.

The oil pumps GMN1, GMN-2 and RMN are supplied with electric power via two inputs of 380 V. In case of power loss by one input, the second input is automatically switched on. Automatic actuation of input occurs both from GMN1 to GMN2 and from GMN2 to GMN1. AMN is powered by 220 V DC.

During turbine operation oil supply is performed by one MMN with oil supply for adjustment and for lubrication of bearings with pressure for adjustment - 0.57 MPa, for lubrication - 0.05 MPa.

During start-up operations, the RMN operates until the protections are tested, then the MMN is turned on.

During operation, MMN1 - MMN2 is on emergency reserve (ALT) and vice versa, during operation, MMN2 - MMN1 is on ALT.

The standby pump starts when the oil pressure in the control system drops to 0.52 MPa, when the pressure in the control system is 0.54 MPa, the following message appears on the control panel screen: "P oil for control is low" and warning sound and light signals are turned on.

Oil pressure for adjustment is measured by three pressure sensors. Automatic actuation of the pump occurs when the oil pressure drops on at least two sensors (protection principle two of three).

RMN is in emergency reserve and is switched on at pressure in lubrication system - 0.04 MPa. At that, "Oil pressure on lubrication is low" message appears on the control panel screen and sound and light signals are turned on. AMN is located on ALT and is switched on at pressure in lubrication system 0.025MPa,

at that turbine is disconnected (but in safe mode for turbine bearings). "Emergency stop" message appears on the control panel screen and sound and light signals are turned on. Oil pressure in lubrication system is measured by three pressure sensors. Automatic switching on and off of the turbine occurs when the oil pressure drops on at least two sensors (protection principle two out of three).

Oil coolers are used to remove heat from the oil.

Type of oil coolers M21 LMZ (B-G) and MB2030 (A).

Oil temperature after oil coolers must be within the limits of not less than 35 С and not more than 45 ° С.

When disconnecting oil coolers for cleaning, it must be taken into account that they are connected in parallel through oil. On the turbine, oil coolers can be disconnected from both the water and oil sides.

Cooling water pressure in oil coolers shall be lower than oil pressure and shall not exceed 0.11 MPa.

During turbine operation the gate valves at oil cooler oil inlet and outlet shall be sealed in open position.

1.3 Turbine Control System

In January 2010, automatic control was reconstructed - the following were dismantled: a control unit, a mechanical automatic safety controller, a speed regulator, a low-pressure servomotor, and non-used oil pipelines.

The design of the throttle valve servomotor remained in the factory version.

Speed controller - electronic.

Power controller - electronic.

Six rotor speed sensors are installed in the front bearing unit.

Shut-off spool unit is installed in place of control unit, which includes:

- throttle valve shut-off spool controls the throttle valve;

- electrohydraulic converter (EHP), controls isolation spool;

- membrane separator - additional protection, controls pulsed oil drain;

- adjustment throttle, for setting of throttle valve opening smoothness.

On the front chair there is a protection unit, which includes six solenoid valves. Low-pressure electric servomotor (LPES) is installed in place of the removed low-pressure servomotor.

The automatic control system provides remote and automatic control of the turbine in all operating modes and its protection in emergency situations and allows to maintain:

- control of rotation speed with preset non-uniformity;

- specified speed with accuracy ± 1 rpm;

- assigned power with accuracy ± 0.5 MW;

- set pressure in heating extraction ± 0.005 MPa.

The Block of Protection (BP) consists of six solenoid valves (SKl11, SKl12, SKl21, SKl22, SKl31, SKl32). Protection unit is used for generation of hydraulic signal for closing of stop valve at reception of signal from protection of electric part of control system.

- 32 are in operating position SKl11 energized and are closed. At reception of protection signal from ECS solenoid valves are de-energized and open oil drain from oil switch of automatic stop valve (ASK). ASK closes.

1.4 Protective devices and actuation setpoints

The turbine has the following protections:

- electronic safety machine;

- axial shift relay - 1 mm;

- safety valve at heating extraction 0.12MPa;

- check valves at all steam bleeds;

- protection against HPH condensate overflow - 700 mm;

- automatic actuation of AMN at decrease of oil pressure for bearings lubrication below 0.025MPa;

- protection against vacuum reduction in the condenser - 400 mm Hg. article;

- protection against temperature drop of superheated steam - 340 ° С;

- protection against a no-charge regime;

- protection against internal damages of the generator.

1.5 Condensing unit

Turbine T2529 is provided with a surface condenser with separation water chambers. Type of capacitor 25 K-8.

The condensation device of the turbine generator is designed to install and maintain a certain vacuum pressure at the outlet branch pipe of the turbine, as well as to convert exhaust steam in the turbine into condensate.

The cooling surface of the condenser is 1830 m2.

The length of the tubes is 6080 mm with a diameter of 22/24 mm.

Pipe boards are attached to condenser housing on studs. Four partitions are installed in the condenser housing to support the tubes between the tube boards. Brass tubes are fixed in both boards by flaring.

Each half of the capacitor is two-way.

Cooling water is supplied and removed from each half separately, which allows cleaning any half with the turbine in operation. The turbine load during the cleaning of one half of the condenser shall be reduced accordingly.

The condensing plant includes two circulation pumps, two condensate pumps, two groups of main steam ejectors with coolers of spent steam of ejectors, and a safety valve.

1.6 Preheater

The high-pressure heater (HPH) is designed to heat the feedwater in an amount equal to the total steam flow rate of the turbine to 150 ° C, HPH type - PV-150-2.

The maximum amount of feed water passed through the HPH is 260 t/h.

The HPH is equipped with an automatic device that bypasses and disconnects it from the water side when the steam part is overfilled with condensate in case of pipe rupture.

Low pressure heaters.

Low pressure surface heater (LPA) type PN75. Water in the IPA is heated by steam from the third (unregulated) extraction after the twenty-fourth stage of the turbine.

The heating surface of the IPA is 75 m2 and consists of U-shaped brass tubes. Tubes are secured in tube board by flaring.

The heater has four sequentially connected strokes.

Gland heater (SP) type PN75.

Condensate heating in SP is performed by steam coming from turbine labyrinth seals

The heater has four sequentially connected strokes.

Steam turbine start-up t-25-29

2.1 Preparation for turbine start-up

The order to start the turbine is given directly by the station shift supervisor, and the chief engineer of the station to start the turbine from overhaul or medium repair.

Turbine start-up, which is in reserve, is carried out under the supervision of the shop shift supervisor or senior driver.

Turbine start-up from overhaul or medium repair is carried out under the supervision of the shop manager or his deputy.

The maintenance personnel, having received the order to start the turbine, must check the completion of the repair work of all equipment and the cleanliness of the workplace, after which he begins to check and assemble the diagrams.

During turbine start-up it is necessary to record the readings of parameters, at deviation of which turbine start-up is prohibited, refer to [10] (steam temperature and pressure, oil temperature and pressure, rotor axial position, vacuum).

The following diagrams must be assembled before starting the turbine:

- assemble the main condensate diagram;

- assemble the diagram of the system of regenerative heaters, extractions, drains, suction;

- assemble superheated steam line diagram;

- check closing of shut-off valves of steam pipelines, start-up bypasses, stop and control valves;

- steam valves for main ejectors must be closed, for utility and start-up ejectors - open;

- all drains from the steam line must be opened to the funnel;

- collect the circulation water circuit;

- assemble the oil circuit;

- check opening of gate valves at oil inlet and outlet at oil coolers, GMN1, MMN-2, RMN, AMN. Check oil level in the oil tank;

- assemble the control circuit.

Get confirmation from the on-duty locksmith of the automation and control shop, and the electrical shop that the electrical part of the protection, automation and alarm elements is checked immediately before start-up, instrumentation (instrumentation) is turned on. Measure clearances by thermal expansion indicators.

2.2 Heating of superheated steam line and steam box

Start RMN, set operating oil pressure on bearings, check oil drain from all bearings.

Open the bypasses from both superheated steam pipelines and heat them through drains to the funnel and household, start-up ejectors without pressure for fifteen minutes. After fifteen minutes, start the pressure rise at a rate of 0.1 MPa per minute. At 0.4 MPa pressure open the drains from the steam line to the tank, close the drain expander to the funnel, close the pressure rise time to the full thirty-five minutes. When warming up, do not allow hydraulic impacts, look at the condition of flange connections.

Upon completion of warm-up, turn on GMN1 on the closed pressure gate valve, gradually open the gate valve completely.

Check ALT of RMN1, 2, RMN power supply input.

Check for voltage in the guaranteed power cabinet. Three 380V, two 220V indicators must be ON. The 220V DC indicator will only light up when the voltage of the two 220V AC inputs disappears.

Check the presence of voltage on the low pressure electric servomotor (ESP).

Check ALT of oil pumps.

Wrench of mode selector switch of operating MMN1 in "operation" position. Set GMN2 AR wrench to "Standby" position, RMN AR and AMN wrenches to "Off" position. Disconnect MMN1 control key, at oil pressure decrease in the control system to 0.52 MPa - MMN2 is activated. Then set the RMN1 and AMN PR wrench to "OFF" position, set the RMN PR wrench to "Standby" position. Disconnect MMN2 control wrench, when oil pressure for bearings lubrication is up to 0.04MPa, RMN is actuated. To put the PR GMN1.2, RMN keys in position "Is disconnected", the PR AMN key - in the provision "Work". Disconnect RMN, at oil pressure for bearings lubrication up to 0.025 MPa AMN is actuated .

Set GMN1, wrench of GMN1 PR to "Operation" position. RMN2 and RMN PR switches are in "Reserve" position. AMN is in "Operation" position.

In this position on the ALT will be GMN2, RMN, AMN.

Further, check of turbine protection against steam-free mode and from stop valve landing is performed, for which it is necessary to check closing of stop valve. Press "Cocking" button, at that solenoid valves close, the oil switch of the stop valve goes to the operating position. Open the stop valve by 25%. Open throttle and reloading valves by "Open ISS" button. Warn the shift supervisor of the station (NSS) about the check of protection against no-charge mode. Any of the protections turn off the turbine, find out from the NSS whether the protection against non-steam mode worked.

Press "Cocking" button, check opening of control valves, open stop valve by 25%. Press "Emergency stop" button, check the stop and control valves fit.

To warm up the steam box, open the stop valve, the control valves must be closed, start warming up the steam box through the drain to the funnel by opening the starting bypass. Heat the steam box at a steam pressure of 0.05 MPa for fifteen minutes.

After heating, close the start-up bypass, drain from the steam box, stop valve.

Start the vacuum rise in the condenser .

For that start one circulation pump (CP), start one condensate pump (CP), release air from steam coolers of main ejectors.

Actuation of circulation pump.

Open the water on the pump gland seals from the utility water line. Open the valve on the air suction line from the circulation pump housing. Check presence of oil in pump and engine bearings. Put into operation the economic ejector for water suction into the pump housing. When vacuum is reached at the suction nozzle of the pump 200210 mm, start the CP motor. Check operation of bearings, rotation of lubricating rings. Check the water pressure by pressure gauge on the pressure nozzle of CP and check the ampere load of the engine. Close the air suction valve from the CP housing and open the water to the gland seals from the pump, and close the domestic water. Open the pressure gate valve at pump outlet. Supply water to control valves of oil coolers and air coolers by opening the gate valve from CP. Check pump and engine operation (vibration, axial run, noise).

Start-up of condensing pump (CP).

Check presence of oil in bearings. Switch on the CP motor. Check water pressure, vibration, noise, axial run, bearing operation.

Close the drains from the extraction steam lines to the gate valves, from U-shaped pipes, transfer the blowdown of the high pressure cylinder to the IPA.

Enable start-up and one group of main ejectors.

Warm steam line for steam supply to seals and supply steam to seals.

Get permission to push the rotor from NSS.

2.3 Turbine rotor push

After warming up the steam box and raising the vacuum, check the closing of the stop valve. Press "Cocking" button to make sure that the oil switch of the stop valve is set to the operating position. The rotary flap opens when the "Cocking" button is pressed. Open the stop valve.

Open throttle and reloading valves, protection wrench and "EGSR turbine shutdown" strap button to set to "Operation" position. Quickly open the start bypass to push the turbine rotor.

As soon as the rotor starts to rotate, close the bypass, check the oil drain from the bearings, listen to the turbine, detect the axial shift before and after the push. After checking the turbine condition open the start-up bypass. Heat the turbine at low rpm - 300-400 rpm.

The rotor is pushed at vacuum in the condenser not less than 300 mm Hg. Art., and steam pressure behind the stop valve should not exceed 0.4 MPa at push. Turn on vacuum protection. For the best heating of the turbine, keep the vacuum in the range of 650 mm Hg. After the push, close the drainage from the U-pipes. During turbine heating monitor oil temperature on bearings and when temperature reaches 40 ° С give water to oil coolers, releasing air through air vents. Perform regular measurements by indicators of thermal movements up to complete heating of the turbine. If the measurements are not symmetrical or different from the previous ones, stop the speed increase. After warming up at low speed, start the speed rise. When vibration occurs, reduce the number of revolutions until vibration disappears, hold for 30 minutes and increase the revolutions again.

During the RPM rise, adjust the oil temperature for bearing lubrication. As rotor speed increases, throttle and reloading valves will be closed and opened by "Open KFOR" button. When rotor RPM 2850 rpm is reached, open fully the starting bypass. Press "Open KFOR" button to increase RPM to 3000 RPM.

2.4 Switching the turbine into the network

Switch on the generator to the network, open the RCP, close the start-up bypass. After the generator is connected to the network, take the load of 1-2 MW, slowly open the main steam valves (GPP), close the launch bypass. Check turbine generator for vibration. Open the water for generator cooling. Permissible cold air temperature 2040 ° С, the difference between cold and hot air shall not exceed 2530 ° С. Generator temperature is adjusted by common drain gate valve from radiators. Gradually load the turbine no more than 1 MW per minute. When the load is reached - 7 MW or more, you can set the power controller (PM) to the "Automatic" position. To unload the turbine below 7 MW, the PM must be set to the "Remote" position. The low pressure electric servomotor (ESP) acting on the rotary shutter can operate in both automatic and remote modes. When operating in automatic mode, the steam pressure in the extraction steam line is set. During LPC operation in automatic mode there is a ban on closing of the rotary flap below 20 ° to prevent closing of LPC bypass pipes. When the load reaches - 15 MW, turn on the adjustable selection of 0.12 MPa and HPH.

When the turbine load is increased, monitor the temperature of the thrust bearing blocks.

2.5 Parameters at which turbine start-up is prohibited

In case of failure of at least one of the protections that cut off steam to the turbine.

In case of defects of the control and steam distribution system, which during load shedding can lead to turbine separation from fresh and selected steam. In case of failure of one of the oil pumps or their automatic actuation. If oil quality does not meet the standards or its temperature drops below the norm. In case of deviation from steam quality standards by chemical composition. If the thermal and mechanical state of the turbines deviates from the permissible values.

3 turbine maintenance during operation

During turbine operation the duties of maintenance personnel include:

- control over the main parameters of the turbine plant, the operation of the control system, as well as individual units and mechanisms;

- check and testing of protection, alarm and automatic switching on of the reserve according to the established schedule;

- testing of standby equipment;

- periodic recording of devices readings in the daily list;

- logging: watchdog, operational switching, as well as fixation of equipment defects;

- monitoring of compliance with safety regulations and fire safety regulations.

During operation of the turbine, the following parameters must be monitored: pressure and temperature of sharp steam, temperature of oil, blocks and inserts in thrust and support bearings, vibration of the turbine unit, oil pressure in the lubrication system of the turbine unit, oil level in the tank, exhaust nozzle temperature, steam pressure in the control stage of the HPC.

3.1 Maintenance of oil supply system

When operating the oil supply systems of the turbine plant, the following shall be ensured: reliability of the units operation in all modes, fire safety, maintenance of normal oil quality and temperature, prevention of oil leaks and its ingress into cooling water.

All switches in the turbine oil system related to the shutdown

equipment at the operating turbine shall be produced under the direct supervision of the shop shift supervisor (NSC) or the senior engineer of the shop (SSC).

The decrease of the oil level in the turbine tank is most often due to the non-density of the oil cooler tubes. To determine the defective oil cooler, it is necessary: close one of the oil cooler gate valves by oil, monitoring the oil pressure and temperature, close the gate valves supplying cooling water to the oil cooler, after ten minutes collect water from the vent, into glassware. If there is oil on the surface of the water, then oil leaks into the cooling water.

If it is necessary to disconnect the oil coolers at the operating turbine for cleaning and determination of pipe loopholes, it is necessary to disconnect not more than one oil cooler after warning the turbine driver who monitors the oil pressure. Start oil cooler by oil at operating turbine in presence of NSC or SMTs. Warn the turbine driver, carefully open the inlet gate valve, pressurize the oil cooler, check its density (after cleaning). Put the oil cooler into operation by opening the gate valves supplying cooling water, and then open the gate valves supplying oil.

Oil temperature shall be monitored during turbine operation. It is very important that the oil temperature is not too high, since the higher the temperature, the faster the oil is oxidized. Maximum permissible temperature of oil coming out of oil coolers and coming to bearings 45 ° С. At the bearing outlet the oil shall be not more than 65 ° C. The temperature of the oil leaving the oil coolers should not be below 35 ° C, since at a lower temperature the viscosity of the oil increases, which disrupts the normal formation of the oil wedge in the bearings and leads to turbine vibration. During operation, check the absence of water in the turbine oil tank at least once a shift by checking through the drain device of the oil tank. During turbine bypass it is necessary to check presence of oil through transparent windows installed in bearing drain oil pipes.

3.2 Condensing plant maintenance

To monitor the operation of the condensing plant, the following values are periodically measured: resolution in the condenser, barometric pressure, water temperature at the inlet and outlet of the condenser,

steam temperature at condenser inlet, condensate temperature at condenser outlet, steam pressure upstream steam jet ejector nozzles, cooling water pressure before and after condenser, condensate salt content, oxygen content in condensate.

During operation of the condensing plant, the following shall be ensured: cleanliness of heating surfaces with observance of normal temperature head and their cleaning, check of vacuum system density and elimination of loopholes.

The penetration of air into the vacuum system of the turbine plant degrades the condenser, causing a number of undesirable events. First of all, air, entering the steam volume of the condenser, significantly degrades the heat transfer coefficient from the condensing steam to the wall of the condensing tubes, thereby reducing the total heat transfer coefficient in the condenser. Significant air suction can cause overloading of air removal devices and deterioration of vacuum for this reason. Another reason for the heat loss in the turbine plant due to the suction of air into the vacuum part is the subcooling of the condensate during condensation of steam from the steam-air mixture. Under these conditions, the deaeration capacity of the capacitor drops sharply and the condensate is strongly saturated with oxygen. The amount of air entering the vacuum system shall not exceed 5 kg/h.

To check the density of the vacuum system, it is necessary: close the suction gate valve on the main ejectors, detect the time of vacuum drop along the vacuum meter, open the suction gate valve .

Vacuum drop shall not exceed 5 mm Hg/min.

Check of condenser water density by condensate salt content and elimination of loopholes. Condensate salt content shall be not more than 5 mceq/l.

Hydraulic compression is performed to ensure hydraulic density of the condenser. Hydraulic pressure testing is performed at the shut-down turbine by filling the steam space of the condenser with chemically purified water. Tubes and tube boards are previously dried with compressed air. The appearance of droplets and leaks occurs at places of cooling water suction.

Check of oxygen content in condensate after condensate pumps (not more than 20 MHeq/l).

The main ejector groups must alternate each week. Check of condensate pumps interlock is checked once a month.

3.3 Operation of regenerative heaters

During operation of the regeneration system, the following must be ensured: observance of the normal temperature head of the heaters, reliability of the heaters in all modes of operation of the turbine plant.

In operating conditions, the most important parameters of the heater is the heating of water and its underheating to the saturation temperature of the heating steam. Deviation of these values from the calculated values indicates abnormal operation of the heaters. At the same time, it should be noted that the calculated values of water heating in the heaters and its underheating to the saturation temperature will occur only at the nominal load of the turbine. With reduced loads, the pressure in the samples will fall and the heating of water in the heaters will decrease.

During operation of regenerative heaters, it is necessary to monitor the condensate level and the serviceable operation of level regulators. Operation is not allowed in the absence of condensate, as well as at too high level in the heater housing.

The duties of the maintenance personnel include systematic testing: signalling when the level in the HPH increases, the operation of check extraction valves, the operation of level regulators in heaters, the operation of protective devices against overflow of the HPH steam space.

Pitot-static tube overflow protections are tested at least once every three months.

3.4 Maintenance of the control system

Stop and control valves shall be run for full stroke - before start-up, for part of stroke - daily during turbine operation.

Check of the density of the station and control valves shall be carried out: after installation of the turbine, before testing the safety machine for acceleration, before and after overhaul, at least once a year.

Density of check valves of controlled takeoffs and actuation of safety valves of these takeoffs shall be checked: before the turbine is tested for load relief, at least once a year.

Check-off valves of all selections are checked: before each start-up and at turbine shutdown, once a month during normal turbine operation.

Check of stop valve closing time and removal of control characteristics at standing turbine and idling are performed: after turbine installation, before and after overhaul or repair of main control and steam distribution units.

In order to avoid non-closing of the turbine stop valve and failure of protection against closing of the stop valve and from non-steam mode:

- set the procedure of stop and control valves cooldown

check of cleanliness of the stop valve oil switch rod (if necessary, clean the rods) once a day at night with recording in the operating list;

- perform scheduled shutdown of turbines by one of process protections at load of 11.5 MW with check of generator shutdown by protection from non-steam mode. Record the activated scoreboard and fallen blinkers in the operational log;

- before each turbine start-up, during protection check, check protection against steam-free mode, actuation of "stop valve closed" annunciator;

The turbine load shedding test at the maximum steam flow rate is performed: when the turbine is accepted after installation, after reconstruction, which changes the dynamic characteristics of the turbine or the static and dynamic control characteristics.

3.5 Maintenance of turbine generator and exciter

During generator and exciter maintenance, personnel shall be assigned:

monitoring the heating of all bearings of the generator and exciter, monitoring the operation of air coolers of the generator and exciter and controlling the temperature of cooling air, monitoring of the temperature of copper and steel of the generator stator, monitoring of the vibration state of the bearings, periodic listening to the generator and exciter, external control over the operation of the brushes on the contact rings and the exciter collector without any work on them, monitoring by the pressure gauge of the presence of fire water pressure to extinguish the fire in the generator, keeping bench insulation protruding gaskets clean and observing the same; to prevent metal objects from closing them, to ensure that there are no outsiders at the generator and exciter.

Cold air temperature shall not be lower than 20 ° C to avoid

funeral services for air coolers. Upper limit of cold temperature

air - 55 ° С. Hot air temperature is not normalized. The difference between hot air temperature and cooling water outlet shall not exceed 10 ° С. An increase in this difference indicates contamination of the air cooler tubes. The reason for the increase in the temperature of cold air, in addition to the contamination of the tubes, may be the air cooler sections (check the vents), the failure of the cooling water valves, and the decrease in water pressure due to contamination of the water filter. The temperature difference, on both sides of the generator, of cold air must be no more than two degrees. A sharp and frequent change in air temperature adversely affects the electrical insulation of the stator windings.

In the event of a sharp change in the generator temperature (more than 2 ° С per hour), the turbine driver immediately informs the shift supervisor of the electric workshop.

Actions in emergency situations

The duty personnel shall be guided by the following instructions on the sequence of actions to eliminate the accident:

- on the basis of the readings of instruments and on the basis of external signs, make a general idea of ​ ​ what happened;

- immediately take measures to eliminate the danger to people and equipment, up to disconnecting the latter, if such danger exists, otherwise take measures to restore normal operation of the equipment;

- Take measures to determine the nature and location of damage to the site affected by the accident. In most cases, the speed of detection of equipment malfunction depends on the speed of accident elimination;

- after all the undamaged equipment has been operated and the location and nature of the damage has been determined, start repairing the damaged equipment, for this purpose, if necessary, the shift supervisor must call the repair personnel;

- Each stage of the accident liquidation should be notified to the immediate supervisor, if possible immediately, without waiting for his interview. Quick and accurate information is the right way to eliminate an accident.

During the liquidation of the accident, you should act quickly accurately, but without any haste. Hasty and rash action very often deepens the accident, instead of eliminating it. If you receive an order during the accident, you need to repeat it, if it is not clear - ask again. Upon execution, immediately inform the person who issued the order.

4.1 Turbine emergency shutdown

If immediate emergency shutdown of the turbine is required, perform the following operations:

- stop steam inlet to the turbine, for that knock out the safety circuit breaker;

- check closing of stop valve and valves regulating steam supply to the turbine, absence of electrical load;

- give a signal to the main control board "Attention, accident!";

- give steam to the turbine seal;

- check RPM by tachometer and rotor axial position;

- mark turbine rotor rundown time;

- if it is necessary to stop the rotor as quickly as possible, the turbine stops with vacuum failure.

Turbine shall be shut down by protection or personnel with vacuum failure in the following cases:

- at increase of the number of revolutions above the limit of the safety machine actuation setpoint;

- at unacceptable axial shift of turbine rotor;

- at unacceptable decrease of oil pressure in turbine lubrication system below 0.025MPa;

- lowering of oil level in the tank beyond the lower limit level (below the red line);

- increase of oil temperature at drain from any bearing to 75 ° С;

- at sharp deviations of fresh steam temperature from the established upper and lower limit values;

- at audible metal sounds and unusual noise inside the turbine;

- in case of sparks and smoke from bearings and end seals of turbine or generator;

- in case of sudden occurrence of strong vibration of turbine generator bearings at 20 McM from steady state or signs of blade apparatus breakage.

- in case of hydraulic impacts in steam lines or turbine;

- in case of oil ignition at the turbine;

- in case of rupture or detection of cracks of steam lines of fresh steam, extractions, pipelines of main condensate and pit. water, oil pipelines, welded and flange connections, as well as in valves and steam distribution boxes;

- in case of generator shutdown due to internal damage;

- at rupture of protective diaphragm on LPC exhaust;

- at unacceptable reduction of oil pressure in the control system;

- in case of voltage loss on remote and automatic control devices or on all instruments;

- in case of circular fire on contact rings of turbine generator rotor, auxiliary generator or exciter manifold.

If there are doubts about the origin and nature of the abnormal sound appearing in the area of ​ ​ the flow part, the active turbine is subject to emergency shutdown in this case, if the occurrence of abnormal sound is accompanied by increased vibration of the machine. If the impact, abnormal sound or vibration of the turbine is accompanied by a sharp decrease in the temperature of fresh steam, then this indicates a water impact.

4.2 Actions in case of deviation from nominal steam parameters

Nominal parameters of fresh steam measured before the turbine stop valve are 2.9 MPa and 400 ° С. During normal operation, the pressure of fresh steam shall not deviate from its nominal value more than ± 0.05 MPa, and the temperature more than ± 5 ° С. Long-term turbine operation is allowed at steam pressure deviations not more than ± 0.1 MPa and temperature

fresh steam not more than ± 10 ° С.

If the pressure of fresh steam deviates by more than 0.01MPa or the temperature of fresh steam is more than 10 ° С, the personnel must restore the nominal parameters. With further gradual change of parameters of fresh steam, namely: when the pressure of fresh steam drops to 2.5 MPa, when the pressure of fresh steam rises to 3.0 MPa, when the temperature of fresh steam rises to 415 ° C, it is necessary to take the most decisive measures to restore normal parameters.

If the pressure of fresh steam decreases below 2.4 MPa, it is necessary to reduce the turbine load. In all cases of steam pressure decrease give a signal to the main board "Attention - pressure drops!" and inform the head of the KTC shift.

When the fresh steam pressure is higher than 3.0 MPa, it is necessary to immediately switch to manual steam throttling using the main steam valve or stop valve, maintaining the superheated steam pressure after the throttle valve at about 2.8 MPa. When the pressure in the superheated steam line to the shutoff valves is reduced to the normal value, it is necessary to reopen the shutoff valve or shutoff valve completely.

When the temperature of superheated steam before the turbine rises to 425 ° С and its operation at these parameters for 30 minutes or the temperature rises above 425 ° С, it is necessary to perform the following: disconnect the turbine by the "Emergency stop" button, send a signal to the MSH "Warning - emergency!," Open the valves for sealing and recirculation, turn off the controlled steam bleeding.

If after the turbine shutdown, the temperature of fresh steam began to decrease below 425 ° С, then it is necessary to drive the safety automatic, put the turbine to idle, switch the generator into the network, gain a load of 1-2 MW and carry out further load lifting provided that the temperature of superheated steam begins to decrease below 420 ° С.

In case of a sharp decrease in the temperature of fresh steam upstream the turbine by 50 ° С, the turbine is disconnected by the "Emergency stop" button, a signal is given to the main control panel "Warning! - accident!" If there is no water discharge to the turbine and the normal state of the unit, the generator is synchronized and connected to the network, the state of the turbine is checked. If the temperature of superheated steam gradually decreases below 370 ° C, it is necessary to open the purges of U-pipes and steam box. Turbine operation with reduced load at fresh steam temperature 350 ° С is permitted for not more than 30 min.

4.3 Actions at vacuum drop in condenser

When the vacuum in the condenser is reduced, it is necessary to:

- pay attention to operation of labyrinth seals and steam pressure in front of ejectors, if necessary, give steam to LPC rear seal;

- reduce the load on the turbine, if the vacuum continues to decrease, sending a signal to the main control board "Warning - machine in danger - taking control." Reduce the load by LPC temperature, preventing the increase of the latter above 55 ° С;

- if the vacuum on the unloaded turbine falls below 400 mm Hg, disconnect the automatic safety control, send a signal to the main control board "Emergency warning";

- check turbine cylinder temperature at rapid vacuum drop before turbine shutdown.

When reducing the vacuum in the condenser, it is necessary to first pay attention to: the level of condensate in the condenser and the operation of the condensate pump, the indication of the condensate water meter, the operation of circulation pumps.

At disconnection of one circulation pump (two CPs were in operation) it is necessary to perform the following:

- give a signal to the GSCH "Attention - the machine is in danger!." Relieve load

on the turbine and maintain it depending on the temperature of the exhaust pipe, which should not be more than 55 ° С, inform the senior engineer of the turbine compartment or the CTC NSC about the incident;

- close the suction of the condenser of the half where CP is disconnected;

- close the pressure gate valve of CP operating in countercurrent mode;

- open the gate valve (jumper) connecting both halves of the capacitor on the pressure part;

- open condenser suction;

- take the maximum load on the turbine generator not exceeding the temperature of the exhaust pipe of the permissible value;

- find out the reason of CP disconnection.

When two circulation pumps are disconnected, the following must be done:

- send the signal to "Attention - machine in danger" MCR;

- remove the load from the turbine so that LPC temperature does not exceed 55 ° С;

- when the vacuum falls below 400 mm Hg, the turbine is disconnected from the network.

When one or both CPs are disconnected by electrical part, press the button or turn the key to disconnect the disconnected CP, in order to avoid self-actuation of the pump during voltage supply. In case of CP disconnection provide oil coolers with water. If it is impossible to supply cooling water to the oil coolers and the oil temperature increase above 65 ° С, the turbine must be stopped.

The condensate pump was shut down. Signs: strong soaring of ejectors, slow vacuum drop.

Perform the following: put the start-up ejector into operation, give a signal to the main control board "Attention - machine in danger," check the switching on of the standby condensate pump.

The condensate pump was switched off, and the standby CP did not turn on.

Perform the following: turn on the standby CP, give the signal

on the "Attention - machine in danger" GSHU, put the start-up ejector into operation,

if the CP has not started to remove the load from the turbine to the minimum value .

If the vacuum is further reduced to 400 mm Hg, the turbine generator is disconnected from the network and stopped.

The necessary qualities of the operational employee should be tireless vigilance and complete self-control, without which at critical moments it is impossible to find a quick and correct method of action.

Turbine shutdown

Disconnect by HPH pair. Switch off the controlled steam extraction 0.12 MPa.

Check AMN ALT. Gradually reduce the electrical load of the turbine at 11.5 MW per minute. When electric load decreases to 2 MW, open the launch bypass. Close GPU. One MMN is in operation. At electric load of 2 MW of one of the protections, disconnect the turbine, the generator must be disconnected by protection from steam-free mode, check closing of the stop, throttle and overload valves, rotor RPM decrease. Close the start-up bypass and stop valve manually. When the number of rotor revolutions decreases, close the water for oil cooling. Press the steam on the main ejectors up to 0.2MPa to gradually reduce the vacuum, to avoid rupture of the safety diaphragm and then close completely. Detect rotor run-down time. Turn off the MMN, turn on the RMN, the oil pump must operate for one hour. Disconnect CP and regenerative heaters. Provide turbine and acute steam line. CPs are switched off as required.

Conclusion

The main purpose of this diploma project is to determine the principles of reliable, economical, safe operation of the steam turbine T2529 after the modernization of the control and oil supply system.

Operation of the steam turbine can be considered properly organized if it meets the following conditions:

- safety for maintenance personnel and for the turbine plant itself;

- reliability, that is, complete absence of accidents, malfunctions and unexpected stops causing the cessation or reduction of heat and electric energy release;

- cost-effectiveness both in terms of specific steam consumption and in terms of maintenance and repair costs.

Security is the main condition and should not be sacrificed in favour of any other requirements under any circumstances.

Steam turbine start-ups and shutdowns are the most important stages of steam turbine plant operation. These operations are associated with significant changes in the mechanical and thermal state of the turbine elements and steam pipelines. Therefore, the operational reliability and durability of the turbine unit significantly depend on the correct conduct of start-up and shutdown modes.

Experience of operation of turbines showed that a significant part of accidents with turbine equipment occurs during start-up due to incorrect heating mode, erroneous actions of personnel, as well as some design flaws of the unit. It should be noted that if a poor-quality start-up or shutdown of the turbine does not lead directly to an accident at the moment, this circumstance will not pass without a trace, but will affect in the future.

The analysis of operating modes proves irrefutably that the occurrence of cracks in turbine housings, valves and in steam pipelines, deflection of rotors and turbine cylinders, warping of horizontal connector flanges, weakening of landing joints, change of structural state of metal, increased wear of bearings, as well as a number of other problems revealed in the initial stage of operation are a direct result of poor-quality launches. It should also be noted that if the turbine is protected from mechanical overloads by various protective devices (safety valves, centrifugal regulators and switches), then the turbine is not protected from unacceptable thermal stresses. In this case, the safety of the turbine depends entirely on the correctness of the chosen maintenance procedure, as well as on the qualification and degree of readiness of the maintenance personnel.

The maintenance personnel of the turbine shop shall have a clear understanding of the physical processes taking place in the individual units and components of the plant and avoid deviations from the instructions developed for this equipment based on the operating experience and recommendations of the manufacturers. Human errors during maintenance of the turbine unit during operation can lead to very serious consequences in the flesh until the equipment is completely destroyed and the entire station is stopped.

The development of the optimal mode of operation of the unit is based on theoretical and experimental studies conducted by research institutes, manufacturers and head adjustment organizations.

теплова схема турбины Т-25-29.dwg