Overview
ISO 3977-4:2002 - "Gas turbines - Procurement - Part 4: Fuels and environment" provides procurement guidance for gas turbine projects focusing on fuel quality and environmental performance. It sets out what information purchasers must supply and what packagers (suppliers/OEMs) should define about acceptable fuels, associated fuel-system conditions, and emissions expectations. Fuel specifications are referenced (e.g., ISO 4261) but not reproduced in full.
Key topics and technical requirements
- Purchaser and packager obligations
- Purchaser: identify fuels, site ambient conditions, operating profiles, regulatory constraints; provide detailed fuel composition and variability limits.
- Packager: define acceptable fuel types and quality ranges; specify pressure/temperature, filtration and compatibility with combustion systems.
- Gaseous and liquid fuels
- Guidance applies to fuels supplied as gas at the turbine interface; includes handling of multiple fuels, condensation limits, and fuel conditioning responsibilities.
- Fuel chemical and physical properties
- Required data: full chemical composition, net and gross specific energy (volumetric and mass basis), Wobbe index and its range, contaminants (sulfur, chlorine, particulates), fuel-bound nitrogen (FBN), and higher hydrocarbons relevant to lean-premix combustors.
- Fuel-system parameters
- Supply pressure/temperature limits, dew point and minimum temperatures to avoid condensation, minimum pressures for start/run, filtration/separator needs, allowable liquids and pressure variation tolerances.
- Environmental performance
- Identification and projection of exhaust emissions (NOx, VOC/UHC, CO, SOx) influenced by fuel properties; noise emission considerations and reference to measurement standards.
- Fuel treatment
- Purchaser responsibility to provide conditioned fuel meeting packager and referenced standards (e.g., ISO 4261).
- Reference methods
- Annexes include practical calculation examples (e.g., Wobbe index) and references to emission and noise measurement standards.
Applications and who uses it
ISO 3977-4 is used by:
- Procurement engineers and spec writers preparing gas turbine purchase agreements
- OEMs, packagers and plant designers defining fuel-compatibility and warranty limits
- Power plant operators and project developers (IGCC, refinery gas, landfill gas, pipeline gas, LNG)
- Environmental compliance officers estimating stack emissions and monitoring needs
- Field engineers responsible for fuel conditioning, commissioning and startup
Practical applications include drafting fuel clauses in contracts, assessing multi-fuel operability, designing fuel conditioning systems, and projecting environmental impact and monitoring requirements.
Related standards
- ISO 3977 (Parts 1–9) - overall gas turbine procurement series
- ISO 4261 - gas turbine fuel specifications (referenced)
- ISO 11042-1/-2 - exhaust gas emission measurement and automated monitoring
- ISO 10494, ISO 6190 - sound/noise measurement methods
- ISO 11086 - gas turbine vocabulary
Keywords: ISO 3977-4, gas turbines procurement, fuel quality, environmental performance, Wobbe index, exhaust emissions, gaseous fuels, packager purchaser obligations.
