IntroductionIntroductionofof

steam turbine steam turbine

What is steam turbine?What is steam turbine?

Machine converting heat energy in the Machine converting heat energy in the steam into mechanical energy at shaftsteam into mechanical energy at shaft

Rotor coupled to shaft, receives its rotary Rotor coupled to shaft, receives its rotary motion direct from action of high velocity motion direct from action of high velocity steam impinging on blade fitted in grooves steam impinging on blade fitted in grooves around rotor peripheralaround rotor peripheral

2 type of turbine – impulse & reaction 2 type of turbine – impulse & reaction

How is achieved?How is achieved?

Carnot cycle – Sadi CarnotCarnot cycle – Sadi CarnotRankine cycleRankine cycle Improvement to Rankine cycleImprovement to Rankine cycle

Where it is fitted?Where it is fitted?

Power plant – single & COGASPower plant – single & COGASULCCULCCSteamship Steamship

When it is introduced?When it is introduced?

History of steam plant / turbineHistory of steam plant / turbine

WW2 – requirement for compact & WW2 – requirement for compact & powerful enginepowerful engine

Introduction to more efficient & higher Introduction to more efficient & higher power diesel plantpower diesel plant

Boom for LNG transportationBoom for LNG transportation Introduction of dual fuel diesel plantIntroduction of dual fuel diesel plant Introduction of diesel electric plantIntroduction of diesel electric plant

Advantages of steam turbineAdvantages of steam turbine

Direct rotary motion on shaftDirect rotary motion on shaftMore even torque on shaftMore even torque on shaftNo internal frictionNo internal frictionNo internal lubrication requiredNo internal lubrication requiredHigh power / weight ratioHigh power / weight ratioSteam expansion down to condenser Steam expansion down to condenser

pressure – high efficiencypressure – high efficiencyLess space occupy for turbine Less space occupy for turbine

Disadvantages steam turbineDisadvantages steam turbine Large heavy condensing plantLarge heavy condensing plant Special heat resisting metal – inlet of HP Special heat resisting metal – inlet of HP

turbinesturbines Separate astern turbine requiredSeparate astern turbine required Large / heavy reduction gearing – propeller Large / heavy reduction gearing – propeller

efficiency at low speedefficiency at low speed Special LO system & bearings – cope with high Special LO system & bearings – cope with high

RPM & tempRPM & temp Complex plant – proper warming through & Complex plant – proper warming through &

cooling down, prevent distortion of rotors & cooling down, prevent distortion of rotors & casingcasing

Higher fuel consumption??Higher fuel consumption??

Comparison Comparison Steam turbineSteam turbine Reciproc engineReciproc engine

ER spacesER spaces Less Less MoreMore

Weight Weight Lighter Lighter Heavy Heavy

Attendance Attendance Less Less More More

Utilisation of high vacuumUtilisation of high vacuum Better Better Not as good Not as good

High temperatureHigh temperature Permit use of high tempPermit use of high temp Not as good Not as good

High pressureHigh pressure Permit use of high pressPermit use of high press Not as good Not as good

Rubbing partsRubbing parts No rubbing partsNo rubbing parts Rubbing parts Rubbing parts

Reciprocating partsReciprocating parts No (no vibe) No (no vibe) Yes (vibration)Yes (vibration)

Overload capacityOverload capacity Extremely goodExtremely good Not as goodNot as good

Reliability Reliability Very goodVery good Not as reliable Not as reliable

Exhaust steam oil contamination Exhaust steam oil contamination Free Free Not freeNot free

Regulation Regulation Excellent Excellent Not as goodNot as good

Economic Economic For medium & large unit For medium & large unit For small size unitFor small size unit

IntroductionIntroductionofof

steam turbine steam turbine

General arrangementGeneral arrangement

Classification Classification

Method of steam expansion Method of steam expansion Impulse turbineImpulse turbineSimple / single stageSimple / single stageVelocity compoundedVelocity compoundedPressure compoundedPressure compoundedPressure – velocity compoundedPressure – velocity compounded

Reaction turbineReaction turbine

Impulse reaction Impulse reaction

Classification (cont/…)Classification (cont/…)

Direction of steam flowDirection of steam flowWith relation to shaftWith relation to shaftAxial flowAxial flowRadial flowRadial flowTangential flowTangential flow

With respect to sequenceWith respect to sequenceSingle flowSingle flowDouble flowDouble flowCompounded, cross or tandem connectedCompounded, cross or tandem connectedRe-entry / repeated flowRe-entry / repeated flow

Classification (cont/…)Classification (cont/…)

According to drive connection According to drive connection Direct connectedDirect connectedHigh speed machinery – feed pump etcHigh speed machinery – feed pump etc

Geared Geared Propulsion, generator at medium speedPropulsion, generator at medium speed

Electric (indirect)Electric (indirect)Turbine drive generator – fast action Turbine drive generator – fast action

Electric (indirect)Electric (indirect)

Advantages:Advantages:Excellent maneuverability Excellent maneuverability

Elimination of astern turbineElimination of astern turbine

Increased economy at reduced powerIncreased economy at reduced power

Disadvantages Disadvantages If no power, no means for propulsionIf no power, no means for propulsion

According to shipboard use According to shipboard use applicationapplication

High pressure condensingHigh pressure condensingMost efficient, more compact, utilises all energyMost efficient, more compact, utilises all energy

High pressure non condensing High pressure non condensing Small generator, feed pump, exhaust used for other Small generator, feed pump, exhaust used for other purposespurposes

Extraction Extraction Bled steam from turbine to drive other machineryBled steam from turbine to drive other machinery

Exhaust Exhaust Exhaust steam to drive turbineExhaust steam to drive turbine

Re-heatingRe-heatingRecycle exhaust steam for other useful workRecycle exhaust steam for other useful work

SINGLE CYLINDER ROTOR

Single cylinder rotorSingle cylinder rotor

Usually low power – up to 15000kWUsually low power – up to 15000kWAdvantages:Advantages:

Reduced installation costsReduced installation costsReduced maintenance costsReduced maintenance costsMainly due to:Mainly due to:Simpler gland steam systemSimpler gland steam systemSimpler LO systemSimpler LO systemSimpler drain systemSimpler drain systemSimpler turbovisory systemSimpler turbovisory systemSimpler gearingSimpler gearing

Single cylinder rotor (cont/…)Single cylinder rotor (cont/…)

Disadvantages:Disadvantages:Higher fuel consumption – steam rate about Higher fuel consumption – steam rate about 1% higher due to:1% higher due to:Blade speed can’t be chosen for max efficiencyBlade speed can’t be chosen for max efficiencyRotor length require larger shaft diameter – Rotor length require larger shaft diameter –

interstage losses are higherinterstage losses are higher

Single failure can affect allSingle failure can affect all

Astern arrangement may have to be overhungAstern arrangement may have to be overhung

CROSS COMPOUNDCROSS COMPOUND

Multi cylinder turbinesMulti cylinder turbines

Marine installations – use at least 2 Marine installations – use at least 2 cylinderscylinders

Each cylinder consist many stagesEach cylinder consist many stagesCommon – HP & LP cylinderCommon – HP & LP cylinderAdvantages:Advantages:

Shorter turbinesShorter turbines

Smaller shaft length & diameterSmaller shaft length & diameter

Smaller bearings – better lubrication Smaller bearings – better lubrication