Experimental studies on the accumulation of individual

The accumulation ratio //min increases with the decrease in bubble size only if n = const (Eq. (10.11)). If the expansion ratio changes simultaneously with dispersity (as is often the case under the conditions of gravitational drainage since the decrease in foam bubble size results in a decrease in the rate of drainage and in the formation of a low expansion ratio foam at the outlet of the foam generator), then a decrease in bubble size leads to a decrease in mm rather than to its increase [23,67]. 

A study of foam separation of sodium butyldiphenylsulphonate in a low expansion ratio foam has shown [46] that the accumulation ratio increases linearly with the increase in the n/2R value, which is in conformity with Eq. (10.8) (Fig. 10.2). An expansion ratio of more than 100 is rarely achieved in standard separation columns and, therefore, under these conditions the accumulation ratio is of the order of several tens or, occasionally, several hundreds. A large number of papers have been dedicated to the study of the possibility to 

The influence of the external dephlegmation on the degree of accumulation is illustrated in Fig. 10.3 [75], With the increase in the part of the foam product taken for dephlegmation, the accumulation ratio increases from about 2 (without dephlegmation) to 4-10 depending on the rate of foaming and the initial surfactant concentration. But even at complete reflux of the whole foam product the accumulation ratio remains not very high. 

Larger values of the accumulation ratio can be reached in dry foams [24,25,47,73,74,76-78]. Kruglyakov and Kuznetsova [47,71] have studied the effect of capillary pressure, foam expansion ratio and dispersity on / mjn. The foam was prepared from NaDoBS and NP20 solutions. The accumulation ratio //m,n increased directly proportional to the expansion ratio (at a = const) and inversely proportional to the parameter a (at n = const) (Fig. 10.4). The maximum degree of accumulation in a NaDoBS solution (0.3 g dm 3 + 0.4 mol dm 3 NaCl) which could be achieved was = 1050 at Ap = 102 kPa. Further increase in 

The accumulation method involving foam drying by creation of a pressure drop in the foam liquid phase is effective for extraction of some proteins from aqueous solutions. The drainage and destruction of foams from aqueous globular protein solutions (BSA, egg albumin, HSA, lysozyme and trypsin) under pressure drop have been studied in [74,76,77]. 

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