Fractionation and Winterization:
is a separation process in which a certain quantity of a mixture (gas, solid, liquid, enzymes, suspension, or isotope) is divided during a phase transition, into a number of smaller quantities (fractions) in which the composition varies according to a gradient. Fractions are collected based on differences in a specific property of the individual components. A common trait in fractionations is the need to find an optimum between the amount of fractions collected and the desired purity in each fraction. Fractionation makes it possible to isolate more than two components in a mixture in a single run. This property sets it apart from other separation techniques.
Fractionation is widely employed in many branches of science and technology. Mixtures of liquids and gases are separated by fractional distillation by difference in boiling point. Fractionation of components also takes place in column chromatography by a difference in affinity between stationary phase and the mobile phase. In fractional crystallization and fractional freezing, chemical substances are fractionated based on difference in solubility at a given temperature. In cell fractionation, cell components are separated by difference in mass.
Winterization is anarrow process, it same as that of dewaxing. This process is applied to remove small quantities of solids from oil that would normally cause cloudiness of the oil when kept at refrigeration temp. these substances can be saturated glycerides or waxes. Waxes are esters fo fatty alcohole and fatty acid, which have a very low solubility in oil. There quantity is different in different oils. Generally varies in between 48-2000 ppm. In order to obtain an oil with good cold stability, the wax contain needs to reduced to the level of about 10 ppm.In this process cooling rate & agitation are carefully controlled to promote the formation of nuclei that will serve as the sites for crystal growth