An apparatus for the automated measurement of compressed liquid densities over the temperature range of 270 K to 470 K and pressures to 50 MPa is described. The heart of the apparatus is a commercial vibrating tube densimeter. In order to minimize the uncertainty in our measurements, several physical and procedural improvements have been implemented beyond that of the commercial instrument operated in a stand-alone mode. The apparatus was designed, and software has been written so that the operation and data acquisition are fully automated. The densimeter was calibrated with measurements of vacuum, propane, and toluene over the temperature and pressure range of the apparatus. Performance measurements on dimethyl ether are reported from 270 K to 470 K to pressures of 46 MPa with an uncertainty of 0.64 to 0.81 kg/m3.
Citation: Industrial and Engineering Chemistry Research
Pub Type: Journals
densimeter calibration, density, dimethyl ether, vibrating tube densimeter