Use of HPLC chromatography, fluidised bed simulation and supercritic eluant chromatography for the industrial purification of fats

The fractionation of fatty compounds is a complex problem because of the mu ltiplicity of product families with different structures and the similarity of the structures inside each family. So it is necessary to find a method with a large field of application and a high efficiency to separate close c ompounds. Chromatography matches these constraints. Indeed, a lot of statio nary phases and eluents are available with different properties increasing the range of molecules to be separated. Technologic progresses have been ac hieved in the field of columns efficiency allowing to reach higher producti vities. Moreover, new processes have been developed, mainly Simulated Movin g Bed (SMB), a continuous chromatographic process. This process shows very interesting results reducing eluent consumption and enhancing productivitie s and purities compared to classical elution processes, mainly for difficul t separations. Different mobile phases can be used answering different cons traints in terms of price, toxicity, solubility.... The most often used is the liquid one because of its versatility and its easy use, but supercritic al one appear to be an interesting alternative because of the specific prop erties of these solvents (low viscosity, high diffusion coefficients, modul ation of the eluent strength with pressure and temperature). All the chroma tographic processes (batch or continuous) can be extrapolated at the indust rial scale either with a liquid or a supercritical eluent. A specific techn ical study must be lead for each case, associated with a technico-economic study to determine what is the best solution for this specific problem. Som e examples are presented to compare the technologies and show the results a nd the costs which can be reached.