Adsorption break point, estimation

The time required from the start of feeding to the break point can be estimated with the assumption of the constant pattern stated above. Thus, substitution of Equation 11.10 into Equation 11.6 gives the following equation for the rate of adsorption ... 

As shown in Figure 11.10, the operations in AFC are regarded as highly specific adsorption and desorption steps. Thus, the overall performance is much affected by the break point, an estimation of which can be made as described in Section 11.5.2. 

When the height of the adsorbent bed is 50 cm, under the same operating conditions given in Example 11.2, estimate the break point (C =0.1 C g) and the length of the adsorption zone z. ... 

In the downstream processing of bioprocesses, fixed-bed adsorbers are used extensively both for the recovery of a target and for the removal of contaminants. Moreover, their performance can be estimated from the breakthrough curve, as stated in Chapter 11. The break time tg is given by Equation 11.13, and the extent of the adsorption capacity of the fixed bed utilized at the break point and loss of adsorbate can be calculated from the break time and the adsorption equilibrium. Affinity chromatography, as weii as some ion-exchange chromatography, are operated as specific adsorption and desorption steps, and the overall performance is affected by the column capacity available at the break point and the total operation time. 

The packed density of the bed, the void fraction of the particle bed, and the density of the feed solution are 386 kgm-3, 0.5 and 1000 kgm-3, respectively. The averaged overall volumetric coefficient of mass transfer KLa is 9.2 h-1, and a constant pattern of the adsorption zone can be assumed in this case. Estimate the break point at which the concentration of A in the effluent becomes 0.1 CA0. 

Adsorption of some organic solvent vapours onto HSZ were studied. Binary adsorption equilibriums except azeotropic mixture-HSZ systems could be correlated by Markham-Benton equation for the whole concentration range, and the break times could be estimated well by using the Extended-MTZ-Method. For azeotropic mixture-HSZ systems, the equilibriums and the break times could be correlated and estimated only for a part of the all concentration range. Then, two azeotropic points appeared in the adsorption equilibriums for IPA-TCE -Y-type system. For this binary systems adsorption equilibrium data could be expressed by proposed equation, similar to liquid-vapour azeotropic equilibrium equation. Breakthrough curve could be simulated using the Stop Go method in the whole range for azeotropic mixture systems as well as for zeotropic systems. 

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