(583h) Benedict-Webb-Rubin Equation of State for an Alternative Fuel, Dimethyl Ether, and Estimation of Thermophysical Properties

The industrial production of dimethyl ether (DME) is about 10,000 ton/year in Japan, and the DME has been mainly used as an aerosol propellant. Recently, DME can be directly synthesized from water gas, carbon monoxide and hydrogen, by use of a new type catalyst dispersed in some fluids. So, a large amount of DME will be supplied in the future of Japan. Considering the molecular structure and the molecular weight, the physical properties of DME will be similar to those of propane or butane. Then, the pure DME and the mixture with liquefied petroleum gas (LPG) are expected to be an alternative energy for industrial, domestic and diesel fuels. However, comparing with propane and butane, there are few available data about DME. The research group, mainly organized by The High Pressure Gas Safety Institute and Liquified Petroleum Gas Center of Japan, intensively investigate the thermophysical properties of DME. This study is one of activities of the project. Therefore, P-V-T relationship was measured for DME by use of a constant volume method in the temperature range from 350.00 to 450.00 K. The eight constants, in Benedict-Webb-Rubin (BWR) equation of state, were optimized for DME by applying Joffe's corresponding state theory. The BWR equation well predict not only for experimental compressibility factor but saturated vapor pressure of DME. Using the BWR eq., other thermophysical properties, like latent heat, heat capacity, speed of sound and so on, were calculated and the diagram were drawn in the wide range of temperature and pressure.