Generalized correlation of latent heats of vaporization of coal-liquid model compounds between their freezing points and critical points

Abstract

Based on Pitzer's thresparameter corresponding states principle (1 955), we have developed a correlation of the latent heat of vaporization of aromatic coal liquid model compounds. Temperature ranges from the freezing point to the critical point. An expansion of the form L = L *(o) + o ' L is used for dimensionless latent heat of vaporization. This model utilizes a nonanalytic functional form based on results derived from renormalization group the0 of the critical point. A simple expression for the latent heat of vaporization, L = coal liquid compounds. Benzene, the basic constituent of the functional groups of the multi-ring coal liquid compounds, is used as the reference compound in the present correlation. This model works very well at both low and high reduced temperatures approaching the critical point (0.02 < E = (T, -T ) / T , < 0.69). About 16 compounds, including single, two, and threering compounds, have been tested and the percent root-mean-square deviations in latent heat of vaporization reported and estimated through our model are 0.42 to 5.27 % . Tables of the coefficients of L *(o) and L *(1) are presented. The contributing terms of the latent heat of vaporization function are also presented in a table for small increments of E. of fluids in the vicin ~~~0 7 3 3 3 + D E0.8333 + D 2 2083 + El€ + i -E3t3 is cast in a corresponding states principle correlation for 2

Prediction of heat capacities and heats of vaporization of organic liquids by group contribution methods

“…In addition, Table 5 brings the calculated values of heat capacities for some substances distributed in all classes of compounds considered in this work at 350 ± 0.5 K. Table 6 gives the average relative deviations between experimental and the predicted values of heats of vaporization of fatty acids, esters, alcohols and triacylglycerols obtained through Eq. (14) and the models suggested by Tu and Liu [35], Carruth and Kobayashi [32], Sivaraman et al [33], Morgan and Kobayashi [34]. It can be noted that Eq.…”

“…However, most of the ARD (221 values) are between 0% and 5% for all classes of compounds, and only thirteen values are higher than 10%. In contrast, none of the models tested [32][33][34][35] can reproduce the collection of experimental values shown in Table 3 with ARD lower than 10%. In fact, Carruth and Kobayashi [32] model gives the poorest predictions with ARD ≤ 5% only for 19 values (using Fedors [14], and Joback and Reid [30]) while Morgan and Kobayashi [34] model gives better predictions with ARD ≤ 5% for 94 values (using Marrero and Gani [29]).…”

“…The predictive capability of one group contribution method proposed by Tu and Liu [35] and of three expressions based on the corresponding-states method, i.e., Carruth and Kobayashi [32], Sivaraman et al [33], and Morgan and Kobayashi [34] has been tested against the collection of experimental values shown in Table 3. Tu and Liu method [35] requires only T c as input, while the other three methods need also the acentric factor.…”

“…For the whole database (264 experimental points), the proposed model overestimated 122 points or 46.2% (53 of fatty acids, 12 of alcohols, 54 of esters and 3 of triacylglycerols) and underestimated 142 points or 53.8% (67 of fatty acids, 25 of alcohols, 44 of esters and 6 of triacylglycerols). It should be noted that the performances of the four models tested [32][33][34][35], besides Eq. (14), were influenced by the methods selected for the prediction of T c and ω.…”

“…Following the work of Cachadiña and Mulero [31], the predictive capabilities of three empirical correlations based on the corresponding-states method, i.e., the expressions of Carruth and chain length 5-26 18 8-21 5-22 21-57 47-57 6-50 6-57 Temperature range ( • C) 25-250 25-150 25-93 25-126 40-180 35-180 25-200 25-250 FA = fatty acids and TAG = triacylglycerols. Kobayashi [32], Sivaraman et al [33] and Morgan and Kobayashi [34], and a group contribution method [35], have been compared through a collection of experimental data from the literature [3,[25][26][27][36][37][38][39][40][41][42]. Also, an extension of the vapor pressure model of Ceriani and Meirelles [2] was established for fatty compounds by using the Clausius-Clapeyron equation [30], which gives a relation between these two properties.…”