Abstract
We have developed a new vibrating tube densimeter by employing the laser doppler technique without using any permanent magnets that cannot avoid the weakening of the magnetic flux density at higher temperatures. Vibration stimulus was applied to the tube with a function generator via a piezoelectric actuator. A He-Ne laser vibrometer is used to detect the vibrating frequency of the tube, and FFT (Fast Fourier Transform) analyzer provides vibration frequency. This setup allowed for us to measure densities with a fairly good accuracy even at high temperatures and high pressures.With the developed equipment, we have conducted the density measurement of methanol-water mixture at 673 K and 40 MPa with an accuracy of 0.009 g/cm3. The density data was analyzed to clarify the features of PVT behavior of this mixture and the solution structure of this mixture was discussed via molecular dynamics simulation results.
