New Experimental Data and Modeling of Glymes: Toward the Development of a Predictive Model for Polyethers

abstract

The design and optimization of industrial processes relies on the availability of robust and accurate models and equations of state (EoSs). Considering the further advancement of the use of soft-SAFT (one version of statistical associating fluid theory) EoS, toward its implementation in industrial processes, a methodology to determine the molecular model and transferable molecular parameters of glymes is discussed herein. In addition to the commonly used vapor pressure and saturated liquid densities, the description of the temperature and pressure effect is improved by including one additional densitypressure and one isothermal compressibility isotherm (both at 323 K) for the molecular parameter optimization. For the guiding of the selection and optimization of the soft-SAFT EoS molecular model and parameters, new high-pressure density data (p?T) and derived properties, such as isothermal compressibility and isobaric thermal expansion, of eight glymes (glycol ethers) have been determined in wide ranges of temperatures (283363 K) and pressures (0.195 MPa). The selected molecular model (considering that only the hydroxyl end groups are able to establish associative interactions) and its parameters provide an excellent description of the experimental data, being able to predict the characteristic crossover point observed for the isobaric thermal expansivities. The robustness and enhanced physical meaning of the molecular model and molecular parameters allow the use of correlations with the molecular weight. The transferability of the proposed molecular parameters is further used to predict the liquid densities for PEGDME250 (a blend of di alkyl ethers similar to the Selexol solvent).

keywords

EQUATION-OF-STATE; ASSOCIATING FLUID THEORY; SOFT-SAFT EQUATION; DIRECTIONAL ATTRACTIVE FORCES; THERMODYNAMIC DERIVATIVE PROPERTIES; PHASE-EQUILIBRIA CALCULATIONS; MOLECULAR-BASED EQUATIONS; VAPOR-LIQUID-EQUILIBRIA; GLYCOL DIMETHYL ETHERS; LENNARD-JONES CHAINS

subject category

Engineering

authors

Navarro, P; Crespo, EA; Costa, JML; Llovell, F; Garcia, J; Rodriguez, F; Carvalho, PJ; Vega, LF; Coutinho, JAP

Groups

G4 - Renewable Materials and Circular Economy

Projects

CICECO - Aveiro Institute of Materials (UID/CTM/50011/2013)

Projeto de Investigação Exploratória: Pedro Carvalho (IF/00758/2015)

acknowledgements

This work was supported by Partex Oil and Gas and developed in the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-014.5-FEDER-007679 (FCT ref UID/CTM/50011/2013), financed by national funds through the FCT/MEC and cofinanced by FEDER under the PT2020 Partnership Agreement. P.J.C. also acknowledges FCT for a contract under the Investigador FCT 2015, contract IF/00758/2015. Additional support from the Comunidad de Madrid government (project S2013/MAE-2800), the Catalan government (project 2014SGR-1582), and the Spanish government (projects CTQ2014-53987 and CTQ2014-53655-R) is also acknowledged. P.N. also thanks the Spanish government for his FPI and mobility grants (BES-2012-052312 and EEBB-I-1610597).