ATAC offers the Hallikainen Vapour Pressure Analyser to measure both True Vapour Pressure and Reid Vapour Pressure
What is Vapour Pressure?
Vapour pressure is one of the most revealing single measurements in the hydrocarbon chain. It quantifies the tendency of a liquid to flash into vapour at a given temperature, and that tendency governs safety, custody transfer, product quality and environmental compliance from the wellhead to the forecourt.
Safety comes first. Crude oil and condensate leaving separators can carry dissolved light ends that expand violently if pressure or temperature conditions change. Knowing true vapour pressure (TVP) allows operators to set stabilisation targets, size relief systems, and confirm that a cargo will not over-pressure a storage tank or vent during loading. Marine terminals routinely cap TVP below roughly 11 psia so that crude remains stable in a ship’s tanks; a mis-measured parcel becomes a demurrage dispute at best and a venting incident at worst.
Vapour Pressure – Safety
Commercially, vapour pressure is a specification with teeth. Gasoline is blended to seasonal Reid Vapour Pressure (RVP) limits: too low and the engine suffers cold-start problems, too high and the fuel vapour-locks and breaches emissions regulation. Butane is among the cheapest blending components available, so refiners want to add every permissible drop — but only measurement tells them where the line sits. A tenth of a psi of unused headroom, multiplied across a refinery’s output, is a significant margin left on the table.
Environmentally, evaporative losses from tanks and loading operations are both a greenhouse gas source and a lost product. Vapour pressure data feeds the emissions models used to calculate those losses and to justify vapour recovery investment.
Vapour Pressure – International Standards – Importance of measuring vapour pressure
Modern practice has moved from the classical ASTM D323 bomb method toward expansion-based analysers such as ASTM D6377 and D5191, which handle live, light-end-rich samples with better repeatability and far smaller sample volumes. Whichever method applies, the principle holds: what is not measured cannot be controlled, and with vapour pressure the consequences of not knowing are measured in dollars, emissions and risk.
For more information about the ATAC Vapour Pressure Analyser, click the link below. Or contact us by emailing sales@atacgroup.com or by phoning +44 (0)1380 818411.
