Measurement of Viscosity and Density of the Mixtures Nitrogen-Carbon Dioxide and Methane-Etane and of the Pure Fluids Carbon Dioxide and Ethane

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The goal of the project is to develop a set of reference data for the viscosity of the pure fluids carbon dioxide and ethane, the binary mixtures carbon dioxide / nitrogen and methane / ethane and for the ternary mixture methane / nitrogen / carbon dioxide. Together with data available from an earlier project, this will result in a reference data set, which enables the validation of existing and the development of new models for gas phase viscosities. In the first phase of the project the apparatuses used to measure density and viscosity were radically revised. The measuring cell of the low density viscosity apparatus (NDVMA) was reconstructed and for both the NDVMA and the combined viscosity/density measuring apparatus (VDMA) new ways to regress results were developed. These measures form a substantially improved basis for the planed measurements. Systematic deviations that occurred in earlier measurements can be avoided this way and the time required for adjusting the apparatuses has substantially been reduced. A set up for gravimetric preparation of commercially not available gas mixtures with well-known composition has been developed. Test measurements with different noble gases prove the operability of the revised apparatus. According to the proposed work schedule, systematic measurements for carbon dioxide at low pressure have been completed in the first phase of the project. The second project phase aims at systematic measurements for ethane, for the two binary mixtures and for the ternary mixture. The foreseen measuring program is ambitious, but it seems realistic taking the improvements of the apparatuses into account. With the new data, a reference data set will be established that covers the temperature range from 253 to 473 K at pressures up to 20 MPa.