P-v-t relationship/saturated vapor pressure of dimethyl ether (dme) as an alternative for liquefied petroleum gas and determination of 8 constants in the benedict-webb-rubin (bwr) equation of state

Abstract

The P-V-T relationship was measured for ethane for 3 isotherms, propane for 10 isotherms, and dimethyl ether (DME) for 10 isotherms using a constant volume method in the temperature range from 350.00 to 450.00 K, and pressure up to 8.341 MPa. Saturated vapor pressure was also measured for propane, butane, and DME by a static method in the temperature range from 238.31 to 402.70 K, and pressure from 57.06 to 5015.5 kPa. The P-V-T relationship of DME showed similar trends to the light hydrocarbons, and the pressure dependence of the compressibility factor was apparently shifted by 20 K for that of propane. The 8 constants in the Benedict-Webb-Rubin (BWR) equation of state were determined for DME. Applying corresponding state theory, 5 constants were evaluated from only the reduced BWR constants for propane and butane. The other 3 constants were determined from the experimental data of the compressibility factor for DME at 402.00 K. The averaged absolute deviation in the compressibility factor was 0.33 % over the whole range of experiments. The saturated vapor pressure deviation was 1.42 % except for the temperature range lower than 293 K.