Gas Turbine: Introduction and Brief Technical

Evaluation Guidelines

hamdi@hammer-engineers.com

Agenda

• A. Introduction to Gas Turbine• B. Technical Bid Evaluation Guidelines

A. Introduction to Gas Turbine

1. Gas Turbine Components and Parts2. Gas Turbine Applications

Component and Parts

Gas Turbine Component (Ground-based engine)

Gas Turbine Component (Turbojet engine)

LP compressor rotor

LP compressor case

High speed gear box

IP compressor

Intermediate case

HP systems

IP turbine LP turbine

Gas Turbine ComponentCompressor:• draws air into the engine• pressure it and deliver to combustion chamberCombustion Chamber:• receives air from compressor• mixing with fuel sprayed from nozzle• burn the mixture to generate maximum possible heat energy (initiate by igniter

plugs, isolated after start-up and remains continuous until the fuel supply is shut off)

• designed to provide mixing, burning, dilution and cooling; by the time the combustion mixture leaves the combustion system and enters the turbine, it is at a mixed average temperature

Turbine:• Turbines are generally easier to design and operate than compressors, since the

hot air flow is expanding rather than being compressed.

Gas Turbine Component (cont.)Inside the Package:• Fuel System• Bearing Lube Oil: Tank, Filters, Pump• Fire and Gas Detection System• Starter / helper driver: Pneumatic, Hydraulic, Variable Speed• Seal gas / oil

Outside the Package:• Enclosure and Fire Protection System• Inlet System: Air filter, Silencer• Exhaust System: Silencer, Stack, Lube Oil Cooler, Motor Control Center, Switchgear• Fire and Gas Detection System• Starter / helper driver: Pneumatic, Hydraulic, Variable Speed• Seal gas / oil

Human Machine Interface:• Machinery monitoring and protection• Driven Load Regulation• Communications (SCADA) interface

Gas Turbine Component (cont.)

• Sensing and Control Instrumentation:- Temperature sensors- Pressure sensors- Flow sensor / surge control- Position sensor- Velocity probes

Brayton Cycle:• (1 - 2) Air is compressed isentropically• (2 – 3) Combustion at constant pressure

• (3 – 4) Expansion at turbine isentropically

Theory of Operation

Application: As Generator

Application: As Mechanical Drive

B. Evaluation Guidelines• Decide the best sizing use guidance / handbook or

based on similarity in past project• Decide shaft arrangement single or twin shaft• Decide the best type Aeroderivative or Heavy Duty• Evaluate Efficiency, performance and loss update →

process calculation

Evaluation Guidelines (cont.)

• Evaluate Hazardous Class review inside and outside →enclosure

• Materials gas composition and site condition→• Monitoring System discuss with operation team (or →

operation requirement)• API review study exception and deviation →

maintaining performances compliance

• Decide the best sizing from various manufacturer see Gas Turbine World Handbook magazine

Consideration: - price per kW- Efficiency LHV

Review Manufacturer population in typical industries:Solar Turbine → Booster ApplicationGE → LNG and Petrochemical

Saturn 20: 1.2 MW GE Frame 3: 15140 HPCentaur 40: 3.5 MW GE Frame 5: 26400 HPCentaur 50: 4.6 MW GE Frame 6: 50700 HPTaurus 60: 5.8 MW Taurus 70: 7.7 MW Mars 90: 9.9 MWMars 100: 11.2 MWTitan 130: 15.3 MW

Evaluation Guidelines (cont.)

• Decide the best shaft Single or Twin Shaft→– Single Shaft: used for power generation– Twin Shaft:

for mech. drive: allows variable speed operationfor power generation: transient response inferior to single shaft unit

Twin Shaft Power Turbine PTC test:→ →– Smaller cranking requirement– Air compressor runs at most efficient speed

Evaluation Guidelines (cont.)

• Decide the best type Aeroderivative vs Heavy Duty→

Evaluation Guidelines (cont.)

Evaluation Guidelines (cont.)Heavy Duty vs Aeroderivative

• Heavy Duty / Industrial Type:- Heavy Casing- Massive stiff shafting with journal bearing- Requires pre-post lube- Cheap but excessive lube- Less frequent maintenance

Evaluation Guidelines (cont.)Heavy Duty vs Aeroderivative

• Aero derivative:- Light Casing- Rotor shafting: 2 or more shaft- Each with its own bearing- Expensive but less lube (aero type)- Higher efficiency but very rapid decrease after washing- Quick overhaul

Evaluation Guidelines (cont.)

• Evaluate Efficiency:Efficiency 30% means:70% of rotational energy produced is required to drive air

compressor in order to maintain sufficient air flow for combustion

Evaluation Guidelines (cont.)

• Evaluate Performance and Loss- Site Rated correction:for Indonesia: 82% of ISO Rated, mostly due hotter Temp

T up, rho up, mass flow down: power downfor Indonesia: 60% RH- Fuel Type- In the case of Dual fuel:

– Liquid hotter and less efficiency than gas– Engine efficiency liquid 1.3% lower

Evaluation Guidelines (cont.)

• Evaluate Performance and Loss- Heat Rate:Amount of heat energy to produce output- Inlet Loss:P drops through inlet filters- Exhaust Loss:P drops through stack, silencer, WHR (be aware that this

will create backpressure)

• Evaluate Lube System - Sleeve & Thrust Bearing typical heavy duty → →

mineral based oil common lube→- Anti friction type ball and/or roller bearing typical →

aero derivative synthetic oil need scavenging → →system

Evaluation Guidelines (cont.)

• Hazardous Class Certificate: - If possible use OEM standard: IEC (Eropa) or NEC

(USA)- Use equivalence of IEC-NEC• Material for ducting, silencer and venting:- Gas composition- SS or CS or CS with internal SS

Evaluation Guidelines (cont.)

• Monitoring System: - System 1 (GE) or Turbotronic (Solar)Be aware of Duplication (by function) and Interface

problem

Evaluation Guidelines (cont.)

• API review:- Convenient purchasing document force OEM to →

supply similar equipment - Limit misunderstanding - Exception are allowed- API 616 (1998) is not for aero derivative, except stated

by client- Alternative design: deviations and reasons

Evaluation Guidelines (cont.)

• API review:- Site rated power don’t forget to ask OEM guarantee →

point- API mechanical test run→- PTC closed loop test→PTC 10 Comp + PTC 22 GT (usually type 2)- Review API 617 as well speed variation control for →

GTCP

Evaluation Guidelines (cont.)

• Scope for Split Arrangement (by EPC or Mfr):- Anti Surge Valve- Lifting Kit- Fuel Valve SS or Aluminum→- Water Wash Cart- Water Mist or CO2 Suppression- Platform- Exhaust Stack- FAT / SAT

Evaluation Guidelines (cont.)

• Technical Bid Evaluation:- List up company (or owner) spec and API requirement- List up deviations for approval discuss with Mfr!!→- List up deviations to API be realistic!!→- Complete Item Check List- Performance Comparison- Guarantee Comparison

Evaluation Guidelines (cont.)

• (Typical) Utility Review:- Electrical System 3 ph, 1 ph→- Compressor Dry Seal System P, flow rate, External→- Start System Direct Drive→- Natural Gas Fuel System P, flow rate, T→- Lube Oil Cooler

Evaluation Guidelines

References

• Manufacturer's Publications• Gas Turbine World Handbook Publications• Internet (public domain) information• Author's experience working as EPC company / Owner

company / Consulting company 's engineer

hamdi@hammer-engineers.com