Binary separation factor

The gap between the ideal and actual binary separation factors greatly depends on the membrane and gas properties as well as the operating conditions. Through an example of He-C02 separation. Fain and Roettger (1993) have demonstrated how significantly... 

The binary separation factor aNa/H is a useful parameter that describes the ion-exchange equilibria because it is dimensionless ... 

Feedwater composition and binary separation factor (acu/ion) for the resin... 

The equivalent concentration of each ion and the binary separation factors for each pair are provided in Tables 3-5. Please note that ... 

In Chapter 8 the equilibrium factor for a single adsorbed species was defined by analogy with the relative volatility. This definition is easily extended to a binary or multicomponent system. For competitive sorption the binary separation factor is defined by... 

The equilibrium factor measures the affinity of the adsorbent for a particular component relative to the same component in the fluid phase whereas the binary separation factor measures the relative preference of the adsorbent for two different competing adsorbates. If the equilibrium obeys the multicomponent Langmuir model ... 

Note-, is the binary separation factor defined by XJjlXjYj. A is the more strongly adsorbed component, B is the less strongly adsorbed component, and C is the desorbent. 

Consider a system made up of three components 1, 2, 3. If two binary separation factors are known, for example, 2 and ttj 3, is it possible to calculate the third ... 

Relative volatility is the volatility separation factor in a vapor-liquid system, i.e., the volatility of one component divided by the volatility of the other. It is the tendency for one component in a liquid mixture to separate upon distillation from the other. The term is expressed as fhe ratio of vapor pressure of the more volatile to the less volatile in the liquid mixture, and therefore g is always equal to 1.0 or greater, g means the relationship of the more volatile or low boiler to the less volatile or high boiler at a constant specific temperature. The greater the value of a, the easier will be the desired separation. Relative volatility can be calculated between any two components in a mixture, binary or multicomponent. One of the substances is chosen as the reference to which the other component is compared. 

Another measure of the preference of an ion exchanger for one other ionic species is the separation factor a. This is defined in a similar way to relative volatility in vapour-liquid binary systems, and is independent of the valencies of the ions. 

Pauls (83) examined the effect of the composition of binary solvent mixtures upon the selectivity and resolution of olive oil TG components. Separation factors (a values) and resolution were calculated for the linoleyldiolein (LOO)-linoleyl-palmitylolein (LPO) and triolein (OOO)-palmityldiolein (POO) pairs in olive oil. Five strong solvents (isopropanol, dichloromethane, chloroform, tetrahydrofuran, and acetone) as well as two weak solvents (methanol and acetonitrile) were employed. 

The separation efficiency for a given membrane with a particular binary gas mixture will be dependent mainly upon three factors gas composition, the pressure ratio between feed and permeate gas, and the sepration factor for the two components. A higher separation factor gives a more selective membrane, resulting in a greater separation efficiency. This parameter is a function of the membrane material and is determined by the individual gas permeation rates. 

Table 8 shows the results for the separation of monosubstituted benzenes using DCA as the host. In the binary systems containing benzene, benzene was excluded from the DCA crystal, with the resulting separation factors less than unity. This makes a complete contrast to the previous results with CA. Two guests, toluene and ethylbenzene, were preferentially included in the DCA crystal. The order of preferential inclusion in DCA can be described as follows ... 

Langmuir isotherm or model Simple mathematical representation of a favorable (type I) isotherm defined by Eq. (2) for a single component and Eq. (4) for a binary mixture. The separation factor for a Langmuir system is independent of concentration. This makes the expression particularly useful for modeling adsorption column dynamics in multicomponent systems. 

A pressure-dependent separation factor a for two substances present in a binary mixture can be defined ... 

For a binary solution in equilibrium with its vapor in accordance with Raoult s law, show that the vapor/liquid separation factor is given by the ratio of pure component vapor pressures. 

In conclusion, the four-zone SMB process scheme is generally the best choice and must be investigated first for binary separations. In several instances, however, alternative schemes offer a better technical solution. The three-zone SMB should be considered when the eluent consumption is not a limiting factor. The five-zone SMB is interesting for multicomponent separation or when an extreme purity of one of the two effluents is wished with a maximum unit throughput. 

When use of the ion-exchange separation method developed in this study was considered it was determined from the separation factor calculated from the stability constants 4] of their complexes with EDTA that a column ratio greater than 40 would be needed to separate them. Experiments showed that a column ratio nearly 10 times larger would be needed to affect their separation with CIEC. Theoretically based studies [7-9] led to success in separation Eu and Gd by the use of HPIEC and a binary displacer. This technique has made the separation of Gd and Eu simple and useful enough to warrant its use as an industrial process. 

The lower the temperature, the greater were j3 13 and J3 12. j3 13 was greater than j3 12 at all the temperatures studied. In this case, the separation factor a in the binary system CO/ CO is defined by Equation 3. 

Isotope separation by means of gas-phase adsorption is quite a new area of study. In the screening test for selective adsorption of CO on zeolite samples from the binary system CO/ CO, it was found that Na-LSX (Si02/Al203 ratio 2.0) adsorbed CO selectively at low temperatures, and fliat its CO separation factor reached 1.1 at 213 K. Compared with cryogenic separation, this separation factor is extremely high. 

From Eqs. (7-1) and (7-2), it follows that the separation factor is purely based on the compositions of the entering and exit streams regardless of their flows. Another measure of the separation efficiency of a membrane process is the extent of separation proposed by Rony [1968]. In the context of applying this index of separation efficiency between two comfionents, it is assumed that there is no difficulty in separating the third component Thus the segregation fractions, fiy, are obtained from the molar flow rates of the permeate and retentate streams on the basis of only two components. The extent of separation is defined as the absolute value of a determinant of a binary separation matrix consisting of the segregation fractions as follows ... 

On the other hand, actual binary mixture tests using porous alumina and glass membranes show separation factor values for helium recovery from oxygen that are lower than what Knudsen diffusion provides, as indicated in Table 7.15. Only Koresh and Soffer [1983a 1983b] show an ideal separation factor of 20 to 40 with a low permeability of 1.2x10 barrers when molecular sieve membranes with a reported pore diameter of 0.3 to 0.5 nm are used. 

Dimethylnaphthalene concentrate contains significant amounts of 2,6-dimethylnaphthalene bound in a binary eutectic with 2,7-dimethylnaphthalene. This eutectic cannot be broken by distillation or solvent crystallization. A practical method for separating this eutectic mixture of 2,7-dimethylnaphthalene and 2,6-dimethylnaphthalene has been achieved. Selective adsorption of 2,7-dimethylnaphthalene from a dimethylnaphthalene concentrate is obtained with sodium type Y molecular sieves. 2,6-Dimethylnaphthalene then can be crystallized from the unadsorbed raffinate fraction. Separation factors of 6 to 8 are obtained, indicating the high selectivity of these particular molecular sieves for this adsorption. Previous work in this area achieved a separation factor of 2.7. A continuous method has been developed for adsorption and desorption of 2,7-dimethylnaphthalene. Toluene has been selected as the optimum desorbent. This process makes 2,7-dimethylnaphthalene potentially available. 

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