Emulsion breaking composition

APPENDIX A Full Scale Treatment of Aluminum Forming Wastewater by Emulsion Breaking and Oil-Water Separation Removal Data Sampling Three 24-Hour or One 72-Hour Composite ... 

Table I. Composition of Two Commercial Emulsion-Breaking Products...

Effect of Continuous Phase Composition. With increasing concentration of Shellsol T in the continuous phase and therefore decreasing bulk phase viscosity (as shown in Figure 13), the emulsion breaking efficiency increases (Figure 14). As expected, the mutual approach of the water droplets will be facilitated in lower viscous continuous phases. 

Figure 14. Effect of continuous phase composition on emulsion breaking efficiency.

A new development is the use of emulsions as fuels for vehicles. The following studies have been selected from the numerous patent sources on this topic. The possibility of making stable water-diesel emulsions containing 10% of water and 0.75% of an emulsifier whose composition is not specified is shown in [248]. When the water content increases, the emulsions break. 

An alkoxylated fatty oil is used in a nonionic composition [1821]. The alkoxylated fatty oil has low solubility in the main emulsion phase. The process is used for breaking emulsions used in wellbore drilling fluids and in oil recovery. 

In general, the tensile strength of the composites based on concentrated emulsions is higher than that based on bulk polymerization the elongation at the break point and the toughness are, however, a little lower. 

Figure 3.2. The mixture of skimmed milk and an apple pectin solution breaks down into the two liquid phases that on mixing form a water-in-water WIW) emulsion where droplets of concentrated casein solution are dispersed in the continuous phase containing pectin and milk whey proteins. This emulsion settled into two hquid layers differing in composition.

The binodal branches do not coincide with the phase diagram axes. This means that the biopolymers are limitedly cosoluble. For instance, on mixing a protein solution A and a polysaccharide solution B a mixture of composition C can be obtained. This mixed solution spontaneously breaks down into two liquid phases, phase D and phase E. Phase D is rich in protein and E is rich in polysaccharide. These two liquid phases form a water-in-water (WIW) emulsion. Hie phase volume ratio is estimated by the inverse lever rule. The phase D/phase E volume ratio equals the ratio of the tieline segments EC/CD. Point F represents the phase separation threshold, that is, the minimal critical concentration of biopolymers required for phase separation to occur. 

In another interesting development, Yei et al. [124] prepared POSS-polystyrene/clay nanocomposites using an emulsion polymerization technique. The emulsion polymerization for both the virgin polystyrene and the nano composite started with stirring a suspension of clay in deionized water for 4h at room temperature. A solution of surfactant ammonium salt of cetylpyridinium chloride or POSS was added and the mixture was stirred for another 4 h. Potassium hydroxide and sodium dodecyl sulphate were added into the solution and the temperature was then raised to 50 °C. Styrene monomer and potassium persulfate were later on added slowly to the flask. Polymerization was performed at 50 °C for 8 h. After cooling, 2.5% aqueous aluminium sulphate was added to the polymerized emulsion, followed by dilute hydrochloric acid, with stirring. Finally, acetone was added to break down the emulsion completely. The polymer was washed several times with methanol and distilled water and then dried overnight in a vacuum oven at 80 °C. The obtained nanocomposite was reported to be exfoliated at up to a 3 wt % content of pristine clay relative to the amount of polystyrene. 

Yiiksel et al. [23,24] describe the use of organic demulsifiers (ternary and quaternary polyamines) to enhance the breaking of oily emulsions. This method is particularly suitable when the composition of the oily waste water is fairly constant but it entails extra costs and maintenance. Ceramic membranes perform much better than polymer membranes because the latter get blocked by the polyamines. 

Emulsion stability is determined by the strength of the interfacial film and the way the adsorbed molecules in it are packed. If the adsorbed molecules in the film are closely packed, and it has some strength and viscoelasticity, it is difficult for the emulsified liquid droplets to break the film. In other words, coalescence is difficult. The emulsion is therefore stable. The molecular structure and the properties of the emulsifiers in the film affect the film s properties. The molecules in the film are more closely packed if the emulsifier has straight chains rather than branched chains. The film strength is increased if mixed emulsifiers are used rather than a single one. The reasons are that (1) the molecules in the film are closely packed, (2) mixed liquid crystals are formed between droplets, and (3) molecular complexes are formed in the interface by emnlsifier compositions. For example, an oil-soluble surfactant mixed with a water-solnble snrfactant works very well to stabilize emulsions (Kang, 2001). 

Rh complexes of composition [Rh(nbd)(33)2]+X containing the phosphonium phosphines 33 (PHOPHOS II, III, VI, X) have been shown to be very active catalysts for the biphasic hydrogenation of n-hexene and maleic acid in water [103, 110]. A definite chain length effect was observed, the system where n = 6 being the most active. The biphasic systems containing longer chain ligands are not well behaved as catalysts since they are prone to formation of stable emulsions which are quite difficult to break. 

Figures 9.43 and 9.44 also illustrate one of the major problems of emulsion membrane systems, i.e., degradation of the emulsion on prolonged contact with the feed solution and high-speed mixing of the product and feed solutions. Prolonged stirring of the emulsion with the feed solution causes the copper concentration in the feed solution to rise as some of the emulsion droplets break. Careful tailoring of the stirring rate and surfactant composition is required in order to minimize premature breaking of the emulsion.

They must bring mechanical energy, shear forces, to break the oil aroma phase into small regular drops (initial coarse emulsion), then to decrease more or less the dispersed drop size (fine emulsion) to improve the stability of emulsion, directly linked to the diameter of dispersed drops. Different techniques such as ultrasound treatment, mixers (agitator. Ultra Turrax), homogenizers (with pressure), and membrane (Microfluidizer ) are used in relation with the desired final emulsion size, the composition of the emulsion, the volumes to produce (100 mL or 10 L), and with an energy consumption linked to energy density concept (Schubert et al., 2009). 

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