Obtaining data liquid systems

Mass transfer across the liquid-solid interface in mechanically agitated liquids containing suspended solid particles has been the subject of much research, and the data obtained for these systems are probably to some extent applicable to systems containing, in addition, a dispersed gas phase. Liquid-solid mass transfer in such systems has apparently not been studied separately. Recently published studies include papers by Calderbank and Jones (C3), Barker and Treybal (B5), Harriott (H4), and Marangozis and Johnson (M3, M4). Satterfield and Sherwood (S2) have reviewed this subject with specific reference to applications in slurry-reactor analysis and design. 

Weisman and Pei also applied their approach to DNB tests with fluids other than water. Without any revision of the approach derived for water, good predictions were obtained for DNB data from systems using liquid nitrogen, anhydrous ammonia, Refrigerant-113, and Refrigerant-11 (see Sec. 5.3.4.2). 

Figure 4 shows the data for PTFE used as the solid phase with the same liquid/liquid system where an oil-wetting cycle is observed. When wetting cycles for plates of the minerals dolomite and marble were obtained for the hexadecane/water system, hybrid wetting cycles such as those shown in Figure 5 were seen. 

Packed Beds. Data on liquid systems using a steady point source of tracer and measurement of a concentration profile have been obtained by Bernard and Wilhelm (B6), Jacques and Vermeulen (Jl), Latinen (L4), and Prausnitz (P9). Blackwell (B16) used the method of sampling from an annular region with the use of Eq. (62). Hartman et al. (H6) used a bed of ion-exchange resin through which a solution of one kind of ion flowed and another was steadily injected at a point source. After steady state conditions were attained, the flows were stopped and the total amount of injected ion determined. The radial dispersion coefficients can be determined from this information without having to measure detailed concentration profiles. 

Measurements of binary vapor-liquid equilibria can be expressed in terms of activity coefficients, and then correlated by the Wilson or other suitable equation. Data on all possible pairs of components can be combined to represent the vapor-liquid behavior of the complete mixture. For exploratory purposes, several rapid experimental techniques are applicable. For example, differential ebulliometry can obtain data for several systems in one laboratory day, from which infinite dilution activity coefficients can be calculated and then used to evaluate the parameters of correlating equations. Chromatography also is a well-developed rapid technique for vapor-liquid equilibrium measurement of extractive distillation systems. The low-boiling solvent is deposited on an inert carrier to serve as the adsorbent. The mathematics is known from which the relative volatility of a pair of substances can be calculated from the effluent trace of the elutriated stream. Some of the literature of these two techniques is cited by Walas (1985, pp. 216-217). 

The above correlation was obtained from the experimental data in a 14.5 cm diameter flat-bottom tank with four baffles over its entire height and a four-blade impeller with d, = dT/2 and with an off-bottom clearance of d,/3. Oguz and Brehm (1988) also proposed the Yagi-Yoshida correlation for both aqueous and organic liquid systems as... 

Related Calculations. This illustration outlines the procedure for obtaining coefficients of a liquid-phase activity-coefficient model from mutual solubility data of partially miscible systems. Use of such models to calculate activity coefficients and to make phase-equilibrium calculations is discussed in Section 3. This leads to estimates of phase compositions in liquid-liquid systems from limited experimental data. At ordinary temperature and pressure, it is simple to obtain experimentally the composition of two coexisting phases, and the technical literature is rich in experimental results for a large variety of binary and ternary systems near 25°C (77°F) and atmospheric pressure. Example 1.21 shows how to apply the same procedure with vapor-liquid equilibrium data. 

Chilton-Colbum Analogy On occasion one will find that heat-transfer-rate data are available for a system in which mass-transfer-rate data are not readily available. The Chilton-Colburn analogy [90,53] (see Tables 5-17-G and 5-19-T) provides a procedure for developing estimates of the mass-transfer rates based on heat-transfer data. Extrapolation of experimental jM or data obtained with gases to predict liquid systems (and vice versa) should be approached with caution, however. When pressure-drop or friction-factor data are available, one may be able to place an upper bound on the rates of heat and mass transfer of f/2. The Chilton-Colburn analogy can be used for simultaneous heat and mass transfer as long as the concentration and temperature fields are independent [Venkatesan and Fogler, AlChE J. 50,1623 (2004)]. 

A summary of metathesis reactions in ionic liquids is presented in Table 7.1. From the data available it appears that these reactions can easily be performed in neat ionic liquids and increased reaction rates are sometimes observed relative to molecular solvents. Co-solvents are used in some cases, mainly to obtain a biphasic system and thereby facilitate product isolation. So far, only imidazolium-type solvents have been employed with variations in the alkyl substitution pattern and the nature of the anion. Apart from the common perfluorinated anions, chloroaluminates have also been used,... 

Tpo obtain vapor-liquid equilibrium data for binary systems, it is now well established that under certain circumstances it can be more accurate and less time consuming to measure the boiling point, the total pressure, and the liquid composition and then use the Gibbs-Duhem relationship to predict vapor composition (I) rather than to measure it. The disadvantage is that there is no way of checking the thermodynamic consistency of the experimental data. 

Fig. 62. Correlation of the Flory-Huggins Interaction Parameter, /, for polystyrene-liquid systems at 25 °C with the relative swelling power (C) of the corresponding liquid at 23 °C as a function of the volume fraction (v) of the polymer in the system. The /-data at v = 1.0, 0.8, 0.6, 0.4, 0.2, and 0.0 are represented respectively by the symbols star, circle, square, triangle pointing upward, triangle pointing downward, and narrow oval. The /-data determined experimentally are represented by the filled symbols, whereas those obtained by interpolation or by extrapolation as noted in Fig. 61 are represented by the corresponding empty symbols...

The adsorption ratios, A = a/ observed thus far for atactic and isotactic systems indicate that self-association can occur in two ways either by expulsion of already-adsorbed molecules (i.e. in the cases that A is <1) or by addition of more adsorbed molecules (i.e. in the cases that A is > 1). Why this is so is not understood. It is curious to note, however, that the solvent in those P-L systems with A > 1 is in every case a cyclic aliphatic liquid, the ring structure of which contains no more than one atom that is not carbon (Nos. 1, 2, 14, and 15 Table 20), whereas none of the solvents in a P-L system with A < 1 is in this category. Because the number of a reported thus far are relatively few (Table 20), owing to the time-consuming procedure and the high technical skill required to obtain data via the protocol described by Guenet, it is not yet possible to adjudicate with certainty whether or not this cyclic vs acyclic differentiation is a real phenomenon or just a fortuitous observation. It does suggest the possibility, however, that the mode of adsorption in the case of cyclic aliphatic molecules may be qualitatively different from that for acyclic molecules. 

An early study on the pressure drop for cocurrent upflow through a packed bed was reported by Turpin and Huntington.37 They obtained data with the use of an air-water system and 5.1-, I0.2-, and 15.3-cm-diameter columns packed with tubular alumina particles of 0.76 and 0.82 cm in diameter. Gas flow rates extending from about 7.8 through 2,298 g cm 2 h-1 and liquid flow rates having a range of 2.347 through 19,560 g cm-2 h-1 were used. The data were correlated by an... 

It should be noted that although the above relation correlates the backmixing coefficient to the fluid properties, no experimental data on systems other than air or nitrogen and water have been reported in the literature. Kato et al.54 obtained data in 6.6-, 12.2-, and 21.4-cm-i.d. columns with particle sizes ranging from 63 through 177 pm and solid concentrations up to 0.2 g solid per cm- of slurry. They correlated the longitudinal dispersion coefficient of the liquid in the slurry by the following dimensionless relation ... 

E. L. Mackor et al., Trans. Faraday Soc. 54, 66, 186 (1958), have measured for both substituted and condensed aromatics in liquid HF-BFa mixtures by using phase partition to obtain data. II0 in HF-NaBF4 at 0°C is about —8.6, so the system is surprisingly acidic. Their pKj values range from 6.3 for toluene to —1.4 for hexamethyl-benzene and —6.4 for 9,10-dimethyl anthracene. I his last is evidently a reasonably strong base in HF. 

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