Overview
ISO 9114:1997 - Crude petroleum - Determination of water content by hydride reaction (field method) specifies a portable, volumetric field procedure for measuring free water in crude petroleum in the range 0.05 % (V/V) to 2 % (V/V). It is designed for situations where laboratory methods are impractical. The method is based on a hydride reaction (calcium hydride with water) that releases hydrogen gas; the gas volume is measured in a gas burette and converted to percent water.
Key topics and requirements
- Principle: Calcium hydride (CaH2) reacts with water to form calcium hydroxide and hydrogen. The hydrogen evolved is proportional to water present and is measured volumetrically.
- Applicable range: 0.05 % to 2.0 % by volume (V/V). Not intended as a primary custody-transfer method unless parties agree.
- Reagents & materials (examples stated):
- Calcium hydride capsules (0.6–0.7 g)
- Light aromatic-free mineral oil (balancing liquid)
- Wetting agent (e.g., sodium dioctyl sulfosuccinate), kerosene, acetone, heptane, water-free silicone grease
- Apparatus: Portable reaction flask (100 ml with specific graduations), two‑position PTFE/tap assembly, gas burette graduated 0–1.0 % H2 (0.01 % units), adjustable reservoir filled with balancing oil and hydrocarbon‑impervious tubing. Design emphasizes gas-tightness and portability.
- Sampling & sample handling: Requires representative sampling and homogenization per ISO 3170 / ISO 3171 and the standard’s Annex A. Homogenization and careful transfer are essential because water and sediment separate easily.
- Procedure highlights: Homogenize sample, transfer specified aliquot, add wetting agent, purge volatiles, introduce CaH2 capsule into the sealed flask, agitate until hydrogen evolution ceases, read burette (V).
- Calculations: Conversion factors depend on sample volume (example: 40 ml → % water = V/2; 20 ml → % = V; 10 ml → % = 2V). For weighed portions and non‑standard temperature/pressure conditions, the standard gives correction formulas.
- Precision: The document provides statistical repeatability and reproducibility expressions (functions of the average result X) for estimating expected method variability.
- Test report: Must reference ISO 9114, product ID, result, any deviations, and test date.
Applications and who uses it
- Field water-content checks on crude oil tanks, barges, pipelines and loading operations when rapid on-site data are needed.
- Used by sampling technicians, tank inspectors, pipeline operators, refinery receiving terminals, and mobile laboratories for operational control, quality assurance, and condition assessment.
- Useful for troubleshooting, receipt checks, or where lab access is delayed - but not normally for custody transfer without agreement.
Related standards
Keywords: ISO 9114:1997, crude petroleum water content, hydride reaction, field method, calcium hydride, gas burette, portable water analysis, petroleum sampling, ISO 3170, ISO 3171.
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