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چکیده
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The goal of this work was to check the ability of the PC-SAFT equation to capture the thermodynamic properties of several pure substances such as amines. To meet this goal high pressure and temperature density data of three pure amines involving diethylamine, dibutylamine and tributylamine were measured at pressures approximately up to 40 MPa and temperatures up to 473 K that have not been reported in the literature. Highly precise densitometer DMA HP was used for density measurements. The measurements at 25 K intervals and along nineteen isobars were done. Densities of the studied samples at atmospheric pressure were compared to those measured with DMA HP densitometer and they are in good agreement. As it was expected, as temperature increases, a pure compound density decreases almost linearly at investigated temperature and pressure ranges. Contrarily, density increases with increasing pressure. The similar result obtained for the amines. Experimental values of densities then were correlated by the Tammann–Tait equation and the PC-SAFT equation of state (Perturbed Chain-Statistical Associating Fluid Theory) [1]. In general it is found in this project that the parameter estimation is very important for the performance of PC-SAFT EoS, and that emphasis should be put on that area as well as on improving the theory. The SAFT EoS was developed around 25 years ago [2], and a large number of papers on the subject have been published since, but many issues still remain unsolved. An important practical problem is how to obtain consistent and optimal parameters. Different parameter sets give similar pure component liquid density results. The performance of the theory depends significantly on the parameter estimation, and this is important to consider if different theories (or association schemes) are compared [3]. The comparisons show that while the improved theory does improve the predictive performance of the model, the choice of association scheme
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