Nonfoaming processes

Again, any type of technique can be used for generating gas bubbles in a nonfoaming adsorptive bubble separation system. The most effective bubble generation techniques for a nonfoaming system are dissolved air flotation and electrolytic flotation. The following are the process descriptions of selected nonfoaming processes. 

One of the most important adsorptive bubble separation processes is nonfoaming flotation. The process is termed flotation because the species being separated from the bulk media are mainly or partially insoluble particulates, such as sludges or agglomerates. It is a nonfoaming process system in which no production of foam is involved. 3.2.3.I. Nonfoaming Precipitate Flotation... 

Pressure drop due to hydrostatic head can be calculated from hquid holdup B.]. For nonfoaming dilute aqueous solutions, R] can be estimated from f i = 1/[1 + 2.5(V/E)(pi/pJ ]. Liquid holdup, which represents the ratio of liqmd-only velocity to actual hquid velocity, also appears to be the principal determinant of the convective coefficient in the boiling zone (Dengler, Sc.D. thesis, MIT, 1952). In other words, the convective coefficient is that calciilated from Eq. (5-50) by using the liquid-only velocity divided by in the Reynolds number. Nucleate boiling augments conveclive heat transfer, primarily when AT s are high and the convective coefficient is low [Chen, Ind Eng. Chem. Process Des. Dev., 5, 322 (1966)]. 

According to the collection procedure for the enriched gas-liquid and/or gas-solid interfaces, adsorptive bubble separation processes or techniques can also be divided into two large categories (a) foam separation, which involves the production of foam in the process, and (b) nonfoaming adsorptive bubble separation, which involves no production of foam. Foam separation can be further subdivide into foam fractionation and flotation. Nonfoaming adsorptive bubble separation, however, can be further subdivided into bubble fractionation, solvent sublation, and noirfoaming flotation. Lemlich (84) and Wang (1,75) provided the definitions of these technical terms in their books. 

If powdered activated carbons (or other adsorbents) are added to water or wastewater for removing soluble pollutants, the spent carbons are then flocculated and floated by a dissolved air flotation cell (or by an electroflotation cell), in which no foam is produced, the process system is termed nonfoaming adsorption flotation (83). 

In the batch adsorptive bubble separation processes, a feed solution was introduced to a bubble separation column (or chamber) containing an aqueous solution of surface-active materials. Surface-active solutes or complexes that are hydrophobic and readily attachable to the air bubbles are carried up to the surface of the water by the bubbles. The enriched material at the top (whether collapsed foam from a foam separation column or overflow liquid from a nonfoaming bubble separation column) and the clarified drain solution at the bottom are withdrawn from the system. The overall material balance for the process is as follows ... 

This chapter is focused on the production of nanoporous polymers by foaming processes because of the advantages of this route that will be explained later nevertheless, nonfoaming techniques are also briefly described. 

Uses Scouring agent for desizing, bleaching processes Features Nonfoaming rec. for high turbulence equip. 

Uses Nonfoaming wetting agent, dispersant for cleaning prods, and processes ... 

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