ABSTRACT
The chemical reactions and separation in supercritical conditions (or fluids) are discussed in this chapter as a basis of process intensification. The principles of supercritical conditions of the solvents and especially of the carbon dioxide, which is considered as green solvent for different applications, are discussed. The benefits and the modeling strategies are also discussed briefly. Some emphasis is made in this chapter on the reactions in supercritical fluids, controlling phase behavior and other characteristics. A resumed explanation of the supercritical fluid reaction and extraction system is presented in figures to be more explicit in the chapter. Based on the experience of the authors, a case study of biomass pretreatment (to reduce recalcitrance of lignocellulose mixture) is presented as innovative proposal recently published in the literature. This case study focuses on the effect of supercritical pretreatment as a green technology (based on an inexpensive solvent as CO2) on the cellulose crystallinity and lignin removal in rice husk where the weak acidic reactions proceed together with products separation to improve the pretreatment of this biomass.
