Separation of Multicomponent Mixtures

Either a more strongly or a more weakly sorbed component may be recovered from mixtures in the separating column with flow reversal at one-end if the column is long enough. The recovery and purification of mix- 

Let us consider first the likely ways to solve the protdem dealing with recovery of B ion firom a three-ion mixture, in which the order of sorb-ability is C B A [23]. 

Preliminary Separation from More Strongly Sorbed Component Mixtures and Subsequent Resolution of Pure Product 

The first step of the above process involves the firontal mixture separation in countercurrent column I on ion-exchange resin where auxiliary D ions are sorbed more weakly than the ions to be separated. 

If the column is sufficiently long, the concentration distribution presented by the scheme in Fig. 6a will be reached in the prescribed time interval. The less strongly sorbed C component is concentrated below the auxiliary ion zone. Somewhat lower than the C zone are the C and B zones. Contained in the zone near the entry of the original solution are the three ions. 

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The sequencing of distillation columns and other types of equipment for the separation of multicomponent mixtures has received much attention in recent years. Although one separator of complex design can sometimes be devised to produce more than two produc ts, more... 

An alternative method, particularly useful for the separation of multicomponent mixtures of hydrocarbons, is to use the simple relation yA = KxA. K values have been measured for a wide range of hydrocarbons at various pressures, and some values are shown in Figure 11.39. 

Several authors have recently reported on the use of Newton-Raphson procedures as applied to the solution of the equation describing a complex fractionator for the separation of multicomponent mixtures. However, it appears that the flexibility to handle various types of electrolyte problems, or to handle... 

We should add that while resolution and peak capacity are excellent criteria of merit for the separation of multicomponent mixtures into discrete zones, other criteria exist, some very general, for judging the efficacy of separation and purification in any separative operation (see Section 1.4). Various terms such as impurity ratio and purity index abound. Rony has developed a criterion termed the extent of separation [22]. Stewart, as well as de Clerk and Cloete, have shown that entropy can be formulated as a very general measure of separation power, as we might expect from the discussion of Section 1.6 [23,24]. An excellent discussion of separation indices, with an emphasis on non-Gaussian zones (below), is found in Dose and Guiochon [25]. 

Separation of multicomponent mixtures, as in selective agglomeration of the combustible matter in coal. 

Separation of Multicomponent Mixtures of Fatty Acid Ethyl Esters from Fishoil by Countercurrent SFE... 

The selectivity of liquid crystals, combined with the high efficiency of capillary columns, makes possible the separation of multicomponent mixtures, including critical pairs of isomers. This is illustrated by the separation of alkylbenzenes up to Cc (Figure 4), alkylbenze-to C 6). 

Figure 3,4) or a better separation of multicomponent mixtures (see Figure 5,6) results from the use of liquid crystalline stationary phases. 

The isolation and concentration of petroleum products can be performed in several ways. The most efficient method is passive adsorption. In this method, the sample along with a tube filled with Tenax TA adsorbent is placed in a thermostated (60-70 °C) tightly closed container, such as a glass jar, for over 10 h. Under these conditions, a balance between compounds present in the headspace of the sample and the sample adsorbed on the polymer adsorbent is established. Adsorbed compounds are subjected to thermodesorbtion then, the desorbed compounds together with the carrier gas are injected onto a GC column, where they are separated and then identified. This approach has enabled easy detection and identification of trace amounts of petroleum products. Headspace analysis with passive adsorption on Tenax TA is normally used for separation and concentration of analytes. Gas chromatography coupled with an autothermal desorber and a mass spectrometer (ATD-GC-MS) is the best technique for separation of multicomponent mixtures... 

McCormick, J. E. and Roche, E. C. (1979) Continuous distillation separation of multicomponent mixtures, in Handbook of Separation Processes for Chemical Engineers, Schweitzer, P. A. (ed.) (McGraw-Hill). 

Important for practical implemetation of zeolitic membranes is the acquisition of permeation data of single components and mixtures and the interpretation of these data in the form of macroscopic models. These models describe the permeation flux of components as a function of partial pressure, composition and temperature. Once good models exist separation units can be designed for the separation of multicomponent mixtures. 

In summary, one can see that separation selectivity for gas and vapor molecules depends on the category of pores (mesopores, supermicropores, and ultramicropores) and on the related transport mechanisms. Either size effect or preferential adsorption effect (irrespective of molecular dimension) is involved in selective separation of multicomponent mixtures. The membrane separation selectivity for two gases is usually expressed either as the ratio between the two pure gas permeation fluxes (ideal selectivity) or between each gas permeation flux measured from the mixture of the two gases (real selectivity). More detailed information on gas and vapor transport in porous ceramic membranes can be found in Ref. [24]. 

Ortiz L, Galan B., San Roman F., and Ibanez R., Kinetics of the separation of multicomponent mixtures by non-dispersive solvent extraction. AIChE J. 47(4), 895-904, 2001. 

Like Helfferich and Klein [9], Rhee et al. [10] studied the separation of multicomponent mixtures by displacement chromatography using the restrictive assumption of the validity of the Langmuir isotherm model and the ideal model. They used a different approach, based on the method of characteristics, and studied the interactions between concentration shocks and centered simple waves [15]. This approach is more directly suited to adsorption chromatography than the... 

This method needs to be extended to the binary case, in order to be useful for practical applications and to allow the determination of the parameters of competitive isotherms and of mass transfer kinetics in the investigation of the separation of multicomponent mixtures. 

In this chapter, the fundamental principles and relationships involved in making multicomponent distillation calculations are developed from first principles. To enhance the visualization of the application of the fundamental principles to this separation process, a variety of special cases are considered which include the determination of bubble-point and dew-point temperatures, single-stage flash separations, multiple-stage separation of binary mixtures, and multiple-stage separation of multicomponent mixtures at the operating conditions of total reflux. 

For the case where the total flow rates Vj and Lj vary throughout each section of the column, these flow rates may be determined by solving the enthalpy balances simultaneously with the above set of equations. For binary mixtures, the desired solution may be found by use of either graphical methods (Refs. 10, 13) or the numerical methods proposed in subsequent chapters for the solution of problems involving the separation of multicomponent mixtures. 

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