title: A Small-Volume Apparatus for the Measurement of Phase Equilibria.
abstract: An apparatus has been designed and constructed for the measurement of vapor-liquid equilibrium properties. The main components of the apparatus consist of an equilibrium cell and a vapor circulation pump. The cell and all of the system valves are housed inside a temperature controlled, insulated aluminum block. The temperature range of the apparatus is 260 K to 380 K to pressures of 6 MPa. The uncertainty of the temperature measurement is 0.03 K, and the uncertainty in the pressure measurement is 9.8 × 10(-4) MPa. An automated data acquisition system is used to measure temperature and pressure at equilibrium. The apparatus has been performance tested by measuring the vapor pressures of propane, butane, and a standard mixture of propane + butane.
authors.affiliation: National Institute of Standards and Technology, Boulder, CO 80305-3328.
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Outcalt
authors.affiliation: National Institute of Standards and Technology, Boulder, CO 80305-3328.
authors.forename: Byung-Chul
authors.initials: BC
authors.lastname: Lee
keywords: butane; phase equilibria; propane; propane + butane; vapor pressure