Reference Correlation of the Viscosity of para-Xylene from the Triple Point to 673 K and up to 110 MPa

Abstract

A new correlation for the viscosity of para-xylene (p-xylene) is presented. The correlation is based upon a body of experimental data that has been critically assessed for internal consistency and for agreement with theory. It is applicable in the temperature range from the triple point to 673 K at pressures up to 110 MPa. The overall uncertainty of the proposed correlation, estimated as the combined expanded uncertainty with a coverage factor of 2, varies from 0.5% for the viscosity of the dilute gas to 5% for the highest temperatures and pressures of interest. Tables of the viscosity generated by the relevant equations, at selected temperatures and pressures and along the saturation line, are provided.

Reference Correlation of the Viscosity of meta-Xylene from 273 to 673 K and up to 200 MPa

“…Similar qualitative behavior was observed for p-xylene. 17 However at 298 K the Mamedov et al 34,35 data are consistent with other data, see Figure 3, and at 423 K and 473 K, see Figure 6, the agreement with Caudwell et al 71 17 toluene, 18 and nheptane, 96 indicates the deviations on average of better than 0.5 % when compared with the most recent reference correlations for these fluids. The inclusion of their data set increased the high temperature limit from 353 K to 408 K and allowed further comparison with Mamedov data.…”

“…14 Recently the work has been extended to cyclic and aromatic hydrocarbons. [15][16][17][18] The present study is a continuation of this effort. The aim of this work is to critically assess the data available in the literature, and provide a correlation for the viscosity of meta-xylene that is valid over a wide range of temperature and pressure, covering the vapor, liquid, and supercritical fluid states.…”

“…The resulting data set, exhibits classical features of the η(T,ρ) representation: (i) viscosity increases steeply at temperatures and densities near the solidification line and (ii) there are no data along subcritical isotherms at densities that lie within the two-phase region. As discussed previously 8,15,17 this makes the choice of the functional form to fit the data rather difficult. As a result, a number of existing viscosity correlations exhibit non-monotonic behavior in the two-phase region.…”

“…94 The enhancement is significant only in a relative narrow window in temperature and density round the critical point. 2,7 Based on the previous studies, 3,5,6,[8][9][10][11][12][13][15][16][17][18] the viscosity critical enhancement of m-xylene is taken as zero. The total lack of industrial applications of m-xylene near its critical temperature and the existence of an only single experimental viscosity datum 39 further supports this choice.…”

“…17 We choose the function ( r , r ) to consist of terms of the general form ( + / r ) r , where D i , E i , k i and n i are the adjustable coefficients. The choice was purely empirical, as we observed that such a function exhibits a monotonic increase within the two-phase region.…”