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a good intro about steam turbines
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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
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