Overview
ISO/TR 11150:2007 is an informative Technical Report from ISO/TC 193 (Natural gas) that explains methods for estimating the hydrocarbon dew point and hydrocarbon content of natural gas. Rather than prescribing a single test method, it describes the measurement principles, sampling challenges, phase‑behaviour concepts (including retrograde condensation, dew line, cricondentherm) and the practical implications of hydrocarbon condensation in pipelines, turbines and gas‑handling equipment. The report is intended to help practitioners interpret and apply existing standards and to understand limitations and uncertainties inherent in dew point determination.
Key Topics
- Definitions and background
- Hydrocarbon dew point, dew line, cricondentherm, and potential hydrocarbon liquid content (PHLC).
- How non‑ideal phase behaviour of hydrocarbon mixtures affects condensation.
- Measurement principles
- Physical methods: direct observation of condensation (cold mirror techniques; historical Deaton & Frost approach).
- Analytical methods: calculation from detailed composition obtained by gas chromatography.
- Gravimetric methods: measurement of potential hydrocarbon liquid (PHLC).
- Sampling requirements
- Guidance from ISO 10715 on representative sampling and precautions for avoiding condensation during sample transfer.
- Uncertainty and interpretation
- Discussion of measurement uncertainty, method dependence, and practical limits of detectability.
- Regulatory and business context
- Examples of specifications (e.g., EASEE‑gas harmonized value: maximum −2 °C hydrocarbon dew point at 1–70 bar) and safety/operational drivers.
Applications
Who uses ISO/TR 11150:2007 and why:
- Gas quality engineers evaluating pipeline and sales‑gas specifications.
- Measurement and sampling specialists designing sampling and monitoring systems to avoid artefacts near dew point.
- Analytical laboratories performing GC composition analysis and dew point calculations.
- Pipeline operators, gas turbine/plant designers and safety regulators who need to manage risks from condensate (clogging, instrument damage, turbine erosion).
Practical uses include method selection, interpreting dew point results, specifying contract limits, and planning mitigation measures (heating, dehydration, condensate traps).
Related Standards
Relevant ISO documents referenced or complementary to ISO/TR 11150:2007:
- ISO 10715 - Natural gas sampling guidelines
- ISO 6327 - Water dew point (cold mirror) techniques (procedure guidance)
- ISO 23874 - Gas chromatographic requirements for hydrocarbon dew point calculation
- ISO 6570 - Determination of potential hydrocarbon liquid content (gravimetric methods)
- ISO 6974, ISO 7504, ISO 14532 - Gas composition and vocabulary standards
ISO/TR 11150:2007 is a practical guide to understanding measurement options, limitations and applications for hydrocarbon dew point and content in natural gas systems.