Supercritical Fluid Extraction: A Global Perspective of the Fundamental Concepts of this Eco-Friendly Extraction Technique

Abstract

Supercritical fluid extraction (SFE) is a green technology that has been applied on a commercial scale for more than three decades. SFE is a high-pressure extraction method in which a mixture of solutes is separated from a solid matrix by bringing the mixture into contact with a fluid in the supercritical state. A supercritical fluid has very particular and unique characteristics, which enable its use as an efficient extraction solvent. Carbon dioxide (CO2) is the most commonly used supercritical fluid and has applications in food, cosmetic, pharmaceutical, and correlated industries. Many research works have already demonstrated that SFE is a technically feasible process that may also be commercially competitive in terms of economic viability. Although SFE is commercially carried out in several countries, it is nonetheless still considered as an emerging technology. This emerging status remains associated with SFE technology because the conventional low-pressure extraction methods remain the most frequently used extraction techniques, in particular due to the comparatively low cost of investment that is required for installing a low-pressure industrial plant. The physical phenomena that occur during SFE have already been extensively investigated, and there is consensus that SFE is a complex phenomenon that involves multicomponent systems. However, various simplifications can be performed to describe SFE for the purpose of process design. Presently, one of the major challenges for researchers in this area is the proposition of practical procedures (experimental and/or calculation methods) in order to simplify the determination of some process parameters which are required for the studies of economic feasibility. This chapter presents the fundamental concepts of SFE and gives special attention to the information that must be available to conduct preliminary