steam turbine 10 oct .pptx

8/10/2019 steam turbine 10 oct .pptx

1/118

Steam Turbines:

Classification

constructional details

By

Mahendra chikhale

Engineer (M) PHS

Condition Monitoring Cell

Rashtriya Chemicals Fertilizers Ltd

Chembur , Mumbai
http://www.rcfltd.com/


2/118

What is Turbine?


3/118

Fundamentals

Steam turbine is power producing d

Steam turbine is a device which cothermal/heat energy of steam frommechanical energy of rotational tothe output shaft and in turn the pow

Steam turbines are utilized to driveof equipment types of numerous sizspeeds in just about every industry sincluding power generation , pulp, paper , steel, chemical , oil and gas

industries.


4/118

History

De Laval, Parsons and Curtis devethe concept for the steam turbine1880s

Modern steam turbines use essen

same concept but many detailedimprovements have been made iintervening years mainly to improvturbine efficiency.


5/118

Principles of operation

The motive power in a steam turbine is obthe rate of change in momentum of a high

of steam impinging on a curved blade whirotate.

The steam from the boiler is expanded in resulting into a high velocity jet. This jet of

impinges on the moving blades, mounted Here it undergoes a change of direction o

which in turn change in momentum and thforce.


6/118

Simple arrangement of a Turbine


7/118


8/118

Principle ofoperation

Impulseturbine

Reactionturbine

Impulse

reactionturbine


9/118

Impulse principle


10/118

Impulse turbine

In impulse turbine, the drop in psteam takes place only in nozzle

moving blades.

This is obtained by making the bpassage of constant cross-sectio


11/118


12/118


13/118

Reaction principle


14/118

Reaction turbine

The drop in pressure takes place in fixed

well as moving blades.

The pressure drop suffered by steam whthrough the moving blades causes a furthgeneration of kinetic energy within these

giving rise to reaction and add to the propwhich is applied through the rotor to the t

The blade passage cross-sectional area (converging type).


15/118

Reaction stages


16/118

Impulse-Reaction turbine

Utilizes the principle of impulse and rea

There are a number of rows of moving battached to the rotor and an equal numbblades attached to the casing.

The fixed blades are set in a reversed m

compared to the moving blades, and actDue to the row of fixed blades at the en

instead of nozzles, steam is admitted forcircumference and hence there is an all-complete admission.


17/118

Nozzle & bucket Arrangements

For Impulse & Reaction Turbine


18/118

Why compounding/multi staging


19/118

Why compounding/multi-staging

In steam engines, it is difficult to obtain fast rotatioturbines have a great difficulty to run at slower sp

For example: Steam expanding from 10.34 bar to

through diverging nozzle will attain velocity of 1.2Therefore, an impulse type turbine wheel of 12 inc

diameter will rotate in the proximity of 35,000 rpm

This impulse wheel would soar to over 75,000 rpmwould suddenly drop.

The reaction type turbine wheel of the same diamwould actually run in the proximity of 69,000 to 75

These speeds are too high for all practical purpos

Rotational speeds are reduced by velocity comppressure compounding.

It is for this reason that multi staging is almost alw


20/118

Blading/compounding

Pressurecompounded velocitycompounded

pressureveloc

compou


21/118

Pressure compounded impulse

Splitting up of the whole pressure drop fsteam chest pressure to the condenser pa series of smaller pressure drops acrossstages of impulse turbine.

The nozzles are fitted into a diaphragm lcasing. This diaphragm separates one wchamber from another.

All rotors are mounted on the same shafblades are attached on the rotor.


22/118

Pressure compounding


23/118

Velocity compounded impulse t

Velocity drop is arranged in many through many moving rows of blad

of a single row of moving blades.

It consists of a nozzle or a set of n

rows of moving blades attached to

the wheel and rows of fixed blades

to the casing.


24/118

Pressure Velocity Compounding


25/118

Pressure-Velocity Compounding


26/118

No ofstages

Singlestage

Multistage


27/118

Single stage turbine


28/118

multi stage turbine


29/118


30/118

Exhaustconditions

Back

pressure Type

Extraction

type

Condensin

Type

B k P St T bi


31/118

Steam exits the turbine at a higher pressure that the at

Back Pressure Steam Turbin

Figure: Back pressure steam turbine

Advantages:

-Simple config

-Low capital co

-Low need of c

-High total effi

Disadvantage

-Larger steam-Electrical load

be matched

Fuel

BoilerTurbine

Process

HP Steam

Condensate

LP

Steam


32/118

Steam obtained by from an intermedia

Remaining steam is

Relatively high cap

lower total efficienc

Control of electrica

independent of the

Extraction Condensing Steam Turbin

Boiler Turbine

Process

HP Steam

LP Steam

Condensate

Condenser

Fuel

Figure: Extraction condensing steam turbine


33/118

All steam is exhaust

very high capital cos

total efficiency

Control of electrical

independent of therm

Extraction Condensing Steam Turbin

Boiler Turbine

HP Steam

Condensate

Condenser

Fuel

Figure: condensing steam turbine


34/118

Si l li d t bi


35/118

Single cylinder turbine

multi cylinder turbine


36/118

multi cylinder turbine


37/118

Flow of

steam

Single flow Compoundflow


38/118

Bi flow turbine


39/118

Bi flow turbine


40/118

Arrangementof cylinders

Tandemarrangement

Crossarrangement

In tandem compound arrangement the rotor

of the cylinder make one common shaft thatgenerator. The rotors may be coupled togeth

Cross compound machines avoid long shaftsenable fewer LP turbines if LP turbine shafts ardifferent speeds.

Two cylinder Tandem arrangement


41/118

Cylinder 2Cylinder 1

Steam IN

Steam OUT

Two cylinder Tandem arrangement

Steam IN Cross cylinder arrangement


42/118

Cylinder 2

Generator 2

Generato

Steam IN

Steam OUT

y g

Cylinder 4Cylinder 3

Cylinder 1


43/118

Why multi-cylinder arrangement

The limit of a single-cylinder turbine is aMW.

Multi-cylinder designs are used in large

e.g. one high pressure (HP) turbine, on

intermediate pressure (IP) turbine and

pressure (LP) turbines.

The IP and LP turbines are usually doub

Schematic Diagram


44/118

g

Turbine components


45/118

Turbine components

Turbine balding : Stationary blades , Mblades

RotorTurning Gear/Barring gear

Casing

Steam Valves

Journal bearing

Thrust bearing


46/118

Turbine rotor


47/118

Turbine rotor

Types of rotors


48/118

Types of rotors

Disc type rotors Drum type r

Types of Rotor


49/118

Types of Rotor

St T bi bl di


50/118

Steam Turbine blading

Rows of stationary balding and Rows of Rotating baldin

Stationary balding- nozzles , vanes , partitions and stati

balding (Diaphragms) Rotating balding buckets , blades and rotating blading

Turbine balding different shapes either impulse bladireaction blading.

Impulse balding are U shaped

Reaction blading aerofile shape

Impulse turbine utilized in high pressure section

Reaction blading utilized in the lower pressure section


51/118

Steam Turbine balding


52/118

Regardless of balding type blade tips may have integral shrouds which ablades

Blade root Attachment


53/118

f l d h


54/118

Types of Blade root Attachment

Dovetail root


55/118

Dovetail root

Internal tree root


56/118

Internal T root


57/118

Bulbous root


58/118

Bulbous root

Straddle tree root


59/118


60/118

Shrouding


61/118

Types of shrouding


62/118

shrouding

Rivettedshroud

IntegralShroud

Lash

Integral shroud


63/118

Riveted shroud


64/118

Riveted types


65/118

Lashing type shrouding


66/118


67/118

rivetedlashinIntegral


68/118

Turning Gear


69/118

Turbine Sealing


70/118

Interstate sealingShaft sealing

interstate sealing


71/118

g


72/118

shaft sealing


73/118


74/118

Turbine seal types


75/118

Carbon rings

Labyrinth seal

Stuffing box

principle


76/118

Simple Labyrinth seal


77/118

Labyrinth seal


78/118

Carbon Seal rings


79/118

Stuffing box


80/118

Turbine casing


81/118

Double casing Single casin

principle


82/118

Journal bearing types
http://en.wikipedia.org/wiki/File:Plainbearing.jpg


83/118

Lobe bearings
http://en.wikipedia.org/wiki/File:Plainbearing.jpg


84/118

Tilting pads journal bearing


85/118

Thrust bearing


86/118

Babbitt

faced collar bearingsTilting pads

Tapered land bearing

Rolling contact (roller or ball) bearing


87/118

A fluid film thrust bearing


88/118


89/118

T

BS

Antifriction Thrust bearing


90/118

The Babbitt face of a tapered land thrust bearing has

fixed pads divided by radial slots. The leading edge o

sector is tapered, allowing an oil wedge to build up and


91/118

secto s tape ed, a o g a o edge to bu d up a d

thrust between the collar and pad

Balancing Drum To contract axial thrust steam is admitted to a dummy( balance )

piston chamber at the low pressure end of the rotor.


92/118

Balancing Drum arrangement


93/118

governor

Control valveStop valve


94/118

turbineGovernor

Speed sensor

Steam IN

Steam OUT

Set point

Power supply

Turbine Valves


95/118

The stop valve

The Control valve

Steam stop valve


96/118

Important to any turbine is the ability to start and stop the ma

normal (controlled) and emergency conditions. For steam tuable to shut off the steam supply quickly & reliably is required

This is normally accomplished by either main steam (MS) stopand throttle (T&T) valves which are usually installed in the inlesteam turbine or on the turbine shell.

Ventilator valvefunction of ventilator valve is to prevent the turbinoverheating during a turbine trip or shutdown.


97/118

ventilator valve

Stop valve

turbine G

conde

turbine

Emergency blow-down valve

Emergency blow-down valve is used to prevent oveduring load rejection.


98/118

turbine

Emergency blow-down valve

Stop valve

conde

turbine

g j

Drain valves


99/118

Turbine drain valves is used to remove moisture


100/118

Trouble shooting of steam


101/118

Corrosion/Erosion


102/118

Broken blades


103/118


104/118

summery

looseness

L li


105/118

Loose coupling

Excessive clearanceof bearings

Loose coupling joint

summery

operation Salt deposition


106/118

Salt deposition

Steam quality

Improper inter-stage sealing

Broken nozzles

Over-speeding due to governorproblem

Salt deposition


107/118

summery

Bearing Lack of lubrication


108/118

gfailure

Lack of lubrication

Poor oil grade

Dirt Contaminated oil

Moisture contamination

Residual magnetism

Design flaws

Bearing failure due tooverheating


109/118

Contaminated oil erosion


110/118


111/118


112/118

Shaft Grounding Locations


113/118

Oil whirl and oil whip


114/118

Oil whirl


115/118

Probe sensing areas


116/118

Probe surfacing area should be properly demagnetized

Combined total electrical & mechanical run out does not expercent of the maximum allowable peak to peak value or

Which ever is greater

For radial vibration probe 0.25 mils

For axila position probes- 0.5 mil

Why steam quality is important?


117/118

Steam Purity Why ?

Impurities can cause damage to turbicomponents by - corrosion, stress corrocorrosion fatigue, erosion-corrosion.

Deposition can cause thermodynamlosses, lower efficiency, upsetting of pdistributions, clogging of seals andclearances


118/118

steam turbine 10 oct .pptx

Documents

Transcript of steam turbine 10 oct .pptx