Construction of a Vibrating U-tube Densimeter and Density Measurements of 0.3 Mole Fraction Methanol - Water Mixture in the Vicinity of the Critical Point

A high-temperature and high-pressure densimeter with an oscillating U-tube for the measurement of supercritical fluid density was constructed. With the apparatus, we measured the density of 0.3 mole fraction methanol - water mixtures in the vicinity of the critical point (T C =587 K, P C =15.1 MPa) as well as toluene as a reference fluid at high temperatures and high pressures.