Effect of Sparger

Handa A, Emery AN Spier RE (1987) Detrimental effects of sparger aeration on suspended mammalian cell cultures and their prevention. Proceedings of the 4th European Congress on Biotechnology 3 601-604. 

FIGURE 11.19 Relation between gas hold-up and superficial gas velocity for different regimes of operation (a) effect of sparger resistance, (b) effect of total pressure and coalescing nature of the gas-liquid system. 

Little effect of sparger type was observed, but the influence of the column diameter was very pronounced the 42-in. column data were an order of magnitude higher than those of the 16-in. column. A draft tube increased the axial mixing at least two to threefold, while a horizontal disc and donut baffles reduced it by a factor of 3. 

Veera, U.R, and Joshi, J.B. (1999), Measurement of gas hold-up profiles by gamma ray tomography Effect of sparger design and height of dispersion in bubble columns, Chemical Engineering Research Design, 77(4) 303-317. 

No significant effect of sectionahzation/liquid physical properties found. No effect of sparger design in the heterogeneous regime. Increasing liquid velocity decreases and hence k a... 

Thorat BN, Shevade AV, Bhilegaonkar KN, Aglave AV, Parasuveera U, Thakre SS, Pandit AB, Sawant SB, Joshi JB. (1998) Effect of sparger design and height to diameter ratio on fractional gas hold-np in bnbble colnmns. Chem. Eng. Res. Des., 76(A) 823-833. 

In contrast to this, the enzyme resin is stressed less by gas sparging than by stirring (see Fig. 18 and 20). The same activity losses were observed first with 1 to 8 times greater specific adiabatic compression power Pj/ V than the maximum power density necessary for stirring. As in the case of the smooth disc, the effects of power input are only weak. The type of gas sparger and therefore the gas exit velocity are of no recognisable importance. The behaviour of the enzyme resin particles is thus completely different from that of the clay min-eral/polymer floes and the oil/water/surfactant droplet system, which are particularly intensively stressed by gas sparging. 

Region without agitation effect. At a very low impeller rotational speed, up to a certain minimum impeller rotational speed, the transfer rate does not improve with stirring. In this region, the mass transfer rate depends on the gas load and type of sparger but is independent of the impeller rotation speed. 

Fig. 37. Effect of hole size of the sparger on critical superficial gas velocity.

---