2NH- GT SHOW

COMPRESSOR & GAS TURBINE WORKSHOP GAS TURBINES - Slide 1

GAS TURBINES & Centrifugal Compressor

Prepared & Presented by

Nauman Hannani

November 2012


Nauman Hannani

I completed my MS in Mechanical Engineering with Specialization in Energy from Chalmers Tekniska Högskola Gothenburg Sweden in 1990. I am working with Gas Turbine from last 25 years & got experience both in PG and O&G in Europe & Asia Pacific. I worked as GT Power Plant operation engineer, after sales manager, GT & combined cycle performance engineer, GT application engineer, fuel & emission engineer, marketing head and sales head. My current position is GM in Rolls-Royce India. Prior to that I was Regional Sales Manager (Oil & Gas), based in Rolls-Royce Singapore since 2001. I was in a similar positions with ABB and ALSTOM in Malaysia since 1997. Prior to 1997, I worked in ABB STAL AB (Finspǻng) Sweden (Now Siemens) 8 years.

Sir Frank Whittle first gas turbine,1930/7 Owned by Rolls-Royce


Agenda ➨  Gas Turbine ➨  Principles ➨  Construction ➨  Types & Applications

➨  Centrifugal Compressor ➨  Compressors Overview ➨  Performance Curves ➨  Applications

• 

COMPRESSOR & GAS TURBINE WORKSHOP GAS TURBINES - Slide 4 main menu

Early Gas Turbine

Click on image to play

Leonardo da Vinci ingeniously used the hot gases from the fire for driving the spit, thereby cooking the meat evenly. Fire provide the energy & conical shape of the chimney made the gases accelerate through the turbine.


Simplified Gas Turbine Comparison with Piston Engine

PIS

TO

N E

NG

INE

GA

S T

UR

BIN

E


Theory : Brayton Cycle Using Ideal Gases

2

4

3

1


Simplified Equations : Power

Power Output = Turbine power output - Compressor power absorbed

⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡−⎟⎟

⎠

⎞⎜⎜⎝

⎛

−−

⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡−⎟⎟

⎠

⎞⎜⎜⎝

⎛

−=

−−

1PPmRT

1kk1

PPmRT

1kkPower

k1k

1

21

k1k

4

34

( )141

2 TT1TTmR

1kkPower −⎟⎟

⎠

⎞⎜⎜⎝

⎛−

−=

4

3k1k

4

3k1k

1

2

1

2

TT

PP

PP

TTSince =⎟⎟

⎠

⎞⎜⎜⎝

⎛=⎟⎟

⎠

⎞⎜⎜⎝

⎛=

−−

⎟⎟⎠

⎞⎜⎜⎝

⎛−⎟⎟

⎠

⎞⎜⎜⎝

⎛−

−= 1

2

13

1

2

1

11 TTTT1

TT

TVP

1kkPower 111 mRTVPSince =

⎟⎟⎠

⎞⎜⎜⎝

⎛−⎟⎟

⎠

⎞⎜⎜⎝

⎛−

−= 1

TT1

TTVP

1kkPower

2

3

1

211

1

31

TTPPower ∝

2

4

3

1


Simplified Equations : Efficiency

InputHeatOutputPowerEfficiency =

⎟⎟⎠

⎞⎜⎜⎝

⎛−⎟⎟

⎠

⎞⎜⎜⎝

⎛−

−= 1

2

13

1

2 TTTT1

TTmR

1kkPower

1

2

1

2

PP

TTEfficiency ∝∝

( )23p TTmCInputHeat −=

( )

( )23p

232

1

1

2

TTmC

TTTT1

TTmR

1kk

Efficiency−

−⎟⎟⎠

⎞⎜⎜⎝

⎛−

−=

⎟⎟⎠

⎞⎜⎜⎝

⎛−

−=

2

1

p TT1

CR

1kkEfficiency

⎟⎟⎠

⎞⎜⎜⎝

⎛−∝

2

11TTEfficiency

2

4

3

1


Pressure & temperature Variation across a Gas Turbine

Highest Pressure : Compressor Discharge Pressure govern the Efficiency of the Gas Turbine Highest Temperature : Turbine Inlet Temperature (TIT) govern the Output of the Gas Turbine

1

31

TTPPower ∝

1

2

1

2

PP

TTEfficiency ∝∝


Actual Working Cycle of Gas Turbine & Impact of Installation

1

8

6 4

2

9


Gas Turbine Performance Ambient Condition Impact

1

2

1

2

PP

TTEfficiency ∝∝

1

31

TTPPower ∝

Ö Power increase with increase in TIT Ö Power decreases with elevation Ö  Power increases with Ambient Temp. Ö Power decreases with Inlet losses Ö Efficiency increases with increase in TIT Ö  Efficiency decreases with Ambient Temp.

•  Power decreases •  Efficiency decreases

Ambient Temperature

Increases

Altitude Increases

•  Power decreases •  Efficiency slightly decreases

Relative Humidity Increases

•  Power slightly increases •  Efficiency slightly decreases


Gas Turbine Performance Installation Impact

1

2

1

2

PP

TTEfficiency ∝∝

1

31

TTPPower ∝

Ö Power increase with increase in TIT Ö Power decreases with elevation Ö  Power increases with Ambient Temp. Ö Power decreases with Inlet losses Ö Efficiency increases with increase in TIT Ö  Efficiency decreases with Ambient Temp.

•  Power decreases •  Efficiency decreases

Exh. losses Increases

Inlet Losses Increases

•  Power decreases •  Efficiency slightly decreases




• 


Gas Turbine Pressure & Temperature air Profile


Gas Turbine on Skid with Auxiliaries & Control

GG LO Module

Fuel Module 1x100%

Hyd Start Module

Dual Certified Electrical Module

Turbine Module

Gas Turbine Control GG LO Module

Fuel Module 1x100%

Hyd Start Module

Dual Certified Electrical Module

Turbine Module

Gas Turbine Control

33 FT


Gas Turbine Package Air Intake Exhaust Stack Ventilation

Driven Equipment (Compressor)

Driven Equipment (Auxiliaries)

Gear Box

Auxiliaries

Gas Generator & Power Turbine Control


•  Compressor & Compressor turbine coupled together and free power turbine drives the DE hence suitable for both MD and PG applications

•  Gas Generator Shaft speed varies (= compressor mass flow varies)

•  Part Load control by optimization of TIT and GG speed (= Good Part Load Efficiency)

•  Light shafts & requires no barring & no interlock

•  Easy to maintain

Gas Turbine Shaft Arrangement

FUEL

CT C B DE PT

Two Shafts

FUEL

C B CT+PT

Single Shaft

DE

•  Compressor, turbine & Driven equip. (DE) coupled to the same shaft

•  Mainly used for power generation •  Shaft speed constant for Power

Generation ( = compressor mass flow constant)

•  Part Load control by TIT (= Poor Part Load Efficiency )

•  Shaft is heavy & requires barring •  Difficult to maintain


Combustor – Types of burner


Influence of temperature on CO and NOx emissions

Combustion temperature K

NOx ppm High temperature promote Unnatural production of NOx.

CO ppm Insufficient air to fuel & local cooling of the flame promotes CO emission.

1400 1500 1600 1700 1800 1900 2000

120

100

80

60

40

20

0

30

25

20

15

10

5

0

NOx CO

Emission Is A Major Concern In Gas Turbine Industry

Effect of Water / Steam Injection

DLE Burner Low flame temp. & good air/fuel mixing due to stage combustion


Dry Low Emissions First Generation DLE System

Combustion Module

Parallel

Staged

\ Pre-Mix Part Load Full Load

Part Load Full Load

Series

Staged

\ Pre-Mix

25% split Cone 50% Split - Full Load

EV & AEV burners

A

B

CAFT LOOKING

FORWARD

A

C

B

Primary 2nd

Air/Fuel Mix




• 


Types of Gas Turbine Cycle

GT with INTERCOOLING

COMBUSTOR

HIGH PRESSURE COMPRESSOR POWER TURBINE

INTERCOOLER

LOW PRESSURE COMPRESSOR

INLET AIR

FUEL

HOT GAS

COOLANT

EXHAUST GAS

GT with REGENERATION

COMBUSTOR

POWER TURBINE COMPRESSOR

FUEL

INLET AIR

COMPRESSED AIR

REHEATED AIR

HOT GAS

EXHAUST GAS

GT with REHEATER

COMPRESSOR TURBINE ONE TURBINE TWO

COMBUSTOR REHEATER

FUEL MORE FUEL

INLET AIR COMPRESSED

AIR

HOT GAS

EXHAUST GAS

Simple Gas Turbine COMBUSTOR

COMPRESSOR

POWER TURBINE

FUEL INLET AIR

Standard Solar Mercury

50

R-R WR-21

Alstom GT24/26


Types of Industrial Gas Turbines • Heavy Weight

• Light Weight

• Aero-derivatives


New bleed duct

Modified casings

Low emission combustion system

Modified power turbine

Industrial Trent

Aero Trent

New compressor

Common IP and HP systems

Fan

Derivation from Aero to Industrial Aircraft Engine Lineage The Industrial Trent Gas Turbine Component


COMPARISON ON TYPES OF GAS TURBINE

TYPICAL DATA HEAVY WEIGHT LIGHT WEIGHT AERO

PRESSURE RATIO

EFFICIENCY

TURBINE INLET TEMP. (TIT)

POWER / WEIGHT RATIO

POWER / SIZE RATIO

TIME BETWEEN OVERHAULS

ENGINE REMOVAL

Low (~10)

Low (~29%)

Low (~950oC)

0.25 MW/ton

0.6 MW/m2

~48000 hrs

No

Medium (~14)

Medium (~33%)

Medium (~1100oC)

0.45 MW/ton

0.7 MW/m2

~25000- 40000 hrs Yes

High (~20)

High (~37%)

High (~1200oC)

0.6 MW/ton

0.8 MW/m2

~25000 hrs Yes

BEARING / LUBRICATION Journal / Mineral

Tilting Pad / Mineral

Ball Bearing / Synthetic

DOWN TIME LONG Short Short


POWER, MW

EFFICIENCY, %

COMPRESSOR STAGES

PRESSURE RATIO

TURBINE INLET TEMP.,TIT

FRAME 5C

28.3

29.4

16

8.9

963

FRAME 5D/ E

980

32.6/ 32

30.3/ 36

17/ 11

10.8/ 17

SGT600

1182

24.7

34.2

10

13.6

SGT700

1260

29

36

11

18

UPRATING OF GE FRAME5 UPRATING OF GT10

Demand of more Power & Efficiency from given size driving industry to go for Aero Technology, Examples…..

Types


Applications

Pow

er G

ener

atio

n O

il &

Gas

main menu

Mar

ine

Aer

ospa

ce


Driving Pipeline Compressors Driving Pumps

Driving Barrel Compressors Driving Electrical Generators

Gas Turbine Applications in Oil & Gas


Simple cycle, Co-generation, Combined Cycle An Aero Engine Power Generating Gas Turbine

Performance at Malaysian conditions

14% Losses

Waste Heat Recovery Unit

53% Heat

33% Electric Power 100% FUEL

GT

33% 100% FUEL

15%

Waste Heat Recovery Unit

16%

Steam Turbine

7oC

36%

67%

33%

100% FUEL Mostly used in O&G application

Maximum Electrical Efficiency

Lowest Electrical & Thermal Efficiency

Mostly used in Utilities & IPP

Maximum Thermal Efficiency

Mostly used in industrial application where both power

and steam is required

Simple Cycle Co-generation

Combined Cycle


Aircraft Engine Lineage The Industrial Trent Gas Turbine Combined Cycle application


Utility PG ü  Location are often urban ü  Site is often safe area ü  Site Overhaul / maintenance is usual ü  Limited outage is acceptable ü  Full load operation ü  Cogen & Combined cycle applications ü  Fuel cost is critical ü  Emissions levels are stringent ü  Redundant units are rare

Oil & Gas ü  Location are often remote or offshore ü  Hazardous environment ü  Site O&M is not usual ü  High demand on reliability & avail. ü  Part load Operation ü  Cogen & CC application are rare ü  Fuel cost is often not critical ü  Emissions becoming a concern ü  Redundant units are common





• 


Compressor • A Compressor is a device that transfers energy to a gaseous fluid to

Ø  overcome the effects of system resistance so the required flow can be supplied to meet process requirements

Ø  raise the pressure of the fluid by at least 5.0 psig (34.5 kPag)

• Devices that develop less than 5 psig are classified as fans or blowers.


Types of Compressors & Selection Criteria

Ø  Positive Displacement Compressors Ø  Piston compressor

(Reciprocating) Ø  Screw compressor Ø  Vane compressor Ø  Lobe compressor

Ø  Dynamic Compressors Ø  Centrifugal compressor Ø  Axial compressor D

isch

arge

pre

ssur

e, p

sia

Inlet flow acfm

10 1

10 5

10 4

10 3

10 2

10 10 5 10 4 10 3 10 2 10 6

Reciprocating

Centrifugal

Axial


Characteristic Curves for Reciprocating, Axial and Centrifugal Compressors


Comparison of Reciprocating, Centrifugal and Axial Compressors

Type Advantages Disadvantages

Centrifugal- Wide operating range- Low maintenance- High reliability

- Unstable at low flow- Moderate efficiency

Axial

- High efficiency- High speed capability- Higher flow for a

given size

- Low pressure ratio per stage- Narrow flow range- Fragile and expensive blading

Positivedisplacement

- Pressure ratiocapability not affectedby gas properties

- Good efficiencies atlow specific speed

- Limited capacity- High weight to capacity ratio- Higher maintenance

requirements- Introduces vibrations into the

system- Bigger foundation

requirements




• 


Compressor Map

More Speed Yields More Head and Flow

Less Flow Gives More Head

Distinct Areas of High Efficiency

Surge & Choke


Compressor Performance Envelope

Head

Flow

Choke Region

Normal Operation

Minimum Speed

Surge Region

The area of desired compressor operation is bounded on the left by the surge line, on the right by the choke line, on the top by the maximum speed line, and on the bottom by the minimum speed line.

Operation of the machine in this region will allow the machine to meet the process requirements with safe and reliable performance.


Typical Performance Curve

109%

100%

85%

60%

70%

80%

100%

110%

120%

60% 70% 80% 90% 100% 110% 120% 130% 140% FLOW (% of design point value)

HEA

D (%

of d

esig

n po

int v

alue

)

90%

☛  Head Rise to Surge

☛  Head fall to Stonewall

☛  Surge Flow

☛  Stonewall Flow

☛  Speed Range

9%

15%

70%

130%

70 - 105% Constant Speed Curve


Fan Laws Flow α Speed

2

1

2

1

NN

QQ

=

2

2

1

2

1

NN

HH

⎥⎦

⎤⎢⎣

⎡=

3

2

1

2

1

NN

PWRPWR

⎥⎦

⎤⎢⎣

⎡=

Head α Speed2

Power α Speed3

% Head

% Flow

25

100 75 50 25

100

75

50 100%

125 110

125 105

105%

70%

70

49


Typical Compressor Map




• 


Multi-Stage Horizontally Split

Horizontally Split Compressors:

Multi-Stage / Multi-Section Compression

•  Low Pressure / High Flow Applications

•  Up to 6300 kPag (900 psig) Maximum Working Pressure

•  Cast Steel and Forged Steel Casings

•  Wet or Dry Gas Seal System

•  Down Nozzle Arrangement is Maintenance Friendly

due to Top Half Casing Removal


Vertically Split Barrel Type Compressors:

Multi-Stage / Multi-Section Compression

•  Variable Flow Range Capability

•  High Pressure Ratio / Head Applications

•  Up to 72,500 kPag (10,500 psig) Maximum Working Pressure


•  Wet or Dry Gas Seal Systems

•  Less Maintenance Friendly for Inspection of Internals

Multi-Stage Vertically Split - Barrel Type


Multi-Stage Centrifugal Impeller Arrangements

• High Head/Pressure Ratio • Thrust via Aerodynamic Compensation - Center

Seal Need to be carefully design • Reduced Recirculation • Reduces Bearing Span for Better Rotor Dynamic

Stability •  Inter-cooling Between Sections

• Conventional

• Medium Head/Pressure Ratio

• Thrust Limitations - Balance Piston

• Higher Recirculation Losses

Straight Through / Front-to-Back Back to Back


Gas Transmission Booster Compressors:

Single-Stage and Multi-Stage Compression

•  Primarily used for natural gas transmission service

•  Very high aerodynamic efficiencies

•  Moderate-to-high volume flows & low-to-moderate heads


•  Dry Gas Seal Systems

Gas Transmission Booster Compressors


Axial Inlet Single-Stage Compressor

Conventional Single-Stage and Multi-Stage Compressor

Gas Transmission Booster Compressors Configuration


Centrifugal Gas Transmission Boosters

Conventional: • Horizontally opposed nozzles/side inlet • Between bearings (and overhung) rotor designs • Wide pressure ratio/head flexibility - up to five stages • High aerodynamic efficiencies - 88% polytropic • Fixed casing design per frame size • Fixed pressure ratings up to 17,240 kPag (2500 psig)

Axial Inlet: • Highest aerodynamic efficiencies - Near 90% isentropic • Limited to single-stage designs (1.45:1 Pressure Ratio) • Overhung rotor design (single dry gas seal design) • Pressures up to 12,410 kPag (1800 psig) • Fixed casing design per frame size


• Upstream Sector

– Gas Injection – Gas Lift – Gas Boosting / Export

• Gas Transmission

–  Gas Pipeline Compression

–  Gas Storage / Withdrawal Compression

Typical Natural Gas Compression Application


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