Apparatus For Accurate Determinations Of Vapor-Liquid Equilibrium Properties And Gas Pvt Properties

A precision apparatus for the experimental determination of vapour-liquid equilibrium properties and PVT properties of gas mixtures has been constructed and thoroughly tested. The apparatus used in the phase equilibrium determinations is of the vapour recirculation type, and that used in the PVT measurements is a Burnett apparatus. The experiments may be performed in the temperature range −180 to +25°C, the temperature being controlled to the nearest ±0.01°C. The temperature can be measured to the nearest 0.01 K using a high precision ac bridge and a calibrated resistance thermometer. The pressure range is from 3 to 350 atm (1 atm = 101.3 kN m −2 ) on the vapour recirculation apparatus and up to 700 atm on the Burnett apparatus; the pressure is determined with a dead weight piston gauge, which has an accuracy of 0.01% of the reading or 0.005 lb in −2 , whichever is the greatest. The composition of the gas and liquid phases is determined using a carefully calibrated gas chromotograph. Both the gas and the liquid samples are injected directly into the carrier gas of the gas chromatograph.