Liquid phase pressure

P(p = average density, lb/ft , two phase tj) = effective average (two-phase)/liquid phase pressure drop ratio corresponding to effective average vaporization x... 

N. S. Isaacs, Liquid Phase Pressure Chemistry, Wiley, New York, 1981. 

The liquid phase pressure drop consists of three parts, unlike that for gas, which consisted of only two parts. The liquid-phase pressure drop is due to the viscous and turbulent modes of friction across the sparger and... 

For this model, the liquid-phase Reynolds number required in equation (10) above and also to compute the liquid-phase pressure drop in the Martinelli parameter was defined in terms of the annular flow area occupied by the liquid phase as follows ... 

Since the liquid phase does not enter the pores, a stable gas-liquid phase interface can be created and maintained (as illustrated in Figure 2.3) as long as the liquid phase pressure is higher than the gas phase pressure and the phase pressure differential AP is between 0 and APq- The pores remain air filled at this condition. The liquid and the gas phases could be flowing at different flow rates on either side of the membrane wall, but the phase interface remains stable aU along the membrane. Thus, by proper control of pressures, the two immiscible phases come in constant contact without a need to disperse one into the other. This allows mass transfer or mass exchange between phases [4—5], such as gas absorption or gas stripping (desorption). 

The excess Gibbs energy of the ternary mixture was expressed through the Wilson [38], NRTL [39] and Zielkiewicz [32] expressions. Because of the agreement between the latter two expressions, detailed results are presented only for the more simple NRTL expression. The parameters in the NRTL equation were found by htting x-P (the composition of liquid phase-pressure) experimental data [32]. The derivatives (9 i/9xi) c2 ( IX2/dx2)xi and (diX2/dxi)x2 in the ternary mixture were found by the analytical differentiation of the NRTL equation. The excess molar volume (V ) in the binary mixtures (i-j) was expressed via the Redlich-Kister equation... 

Selection of the ideal support for a liquid membrane requires careful consideration of the characteristics of the particular separation such as gas or liquid phase, pressure, temperature, and chemical nature of the phases in contact with the membrane. However, a few generalizations can be made. The ideal support should be thin (< 100 pm), have a high porosity (> 50%), have a mean pore size of less than 0.1 pm, have a narrow pore size distribution, and be available in geometries that will produce permeators with a high surface area /volume ratio. 

The chloromethanes are reacted with HF to form the chlorofluoromethanes and HC1. The reaction takes place in the gas phase at 150°C on fixed bed catalysts containing AlF3, CrF3, or CrOF. Halogen exchange also can take place in the liquid phase. Pressures of 2—5 bar and temperatures about 100°C are used [162]. 

Pressure of liquid phase = pressure of vapor phase... 

Table 2.1 Correction factor, for two-phase flow based on the liquid phase pressure drop.

In case of total vapor pressure experiments, usually the compositions of the liquid phase, pressure and temperature are given only. Sometimes compositions of the vapor phase are provided additionally. 

The equilibrium constant is strongly temperature dependent (for reactions in the liquid phase pressure dependency is neglectible). The rate equation for the ester formation is... 

Curvature effect. For a curved interface, the gas and liquid phase pressures are related by the well-known Young-Laplace equation derived in Chapter 2,... 

A two-phase flash problem can be stated as follows. Given the number of moles of feed, the mole fraction of components in the feed i = 1,..., c (i.e., Zj = 1), and pressure and temperature, find the number of the moles in the gas and liquid phases, V, and L, respectively, and the mole fractions of the gas and liquid phases, and jCj, respectively. We assume that the interface between the gas and liquid phases is flat, which implies that the gas and liquid phase pressures are the same. Figure 4.1 shows a sketch for the process. The application of this type of calculation is shown in Fig. 4.2, where a gas phase from the gas cap of a hydrocarbon reservoir at pressure and temperature is flashed at a lower pressure P and a lower temperature T. Similarly, the oil phase from the oil column at temperature and pressure can be flashed at a lower pressure Patid a lower temperature T(see Fig. 4.2). 

Direct compression of liquid phase Pressure No No gas phase present... 

Example 5.15 Effect of Microporous Layer Often, to enhance water transport, a special highly hydrophobic coating between the DM and catalyst layer will be used, called the microporous layer (MPL). This layer has an average pore size somewhere between that of the catalyst layer and the macro-DM. Consider a bilayered DM coated with an MPL. In equilibrium, there will be a liquid saturation jump at the interface between the MPL and the DM, because of the discontinuity in pore sizes. That is, in order to have a liquid phase pressure balance at the MPL-DM interface, as required for equilibrium, the saturation in the MPL will be lower, since the pore size is lower, increasing the capillary pressure. Assume... 

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