Supercritical fluid processing

Other. Numerous other supercritical fluid processes and techniques have been and are continuing to be developed. The novel spray appHcation UNICARB uses supercritical CO2 to replace volatile diluents in coating formulations, thereby reducing the volatile organic compound emissions by up to 80% (128). Rapid expansion of CO2 iu the spray can also improve the quaUty of coatings, thus performance benefits are obtained in a process developed for environmental advantages. 

Y. Ikushima, N. Saito, K. Hatakeda and S. Ito, in Supercritical Fluid Processing of Food Biomaterials... 

Rapid solidification and devitrification of amorphous metals and metallic glasses Combustion-flame chemical vapor condensation processes (Kear) Induction-heating chemical vapor condensation processes DC and RF magnetron sputtering, inclusive of the method of thermalization Laser ablation methods Supercritical fluid processing... 

Solid-fluid equilibria are important for supercritical fluid processing design (Bush and Eckert, 1998). 

In a supercritical fluid process, advantages in process performance must exceed the penalties from the requirement for elevated pressures. It is pmdent to undertake a formal hazard analysis of the SCF process to identify unknown and potentially dangerous design conditions (see Hazard analysis and risk assessment). 

Identification of certain key areas in which supercritical fluid processing could be technically, as well as economically, superior to traditional separation processes. 

The so-called subcooled liquid approach was also suggested in the literature in order to overcome the difficulties connected with the pure component properties of the solid compound. This approach is commonly used for the calculation of the liquid-solid equilibria, and for solubility calculation of solids in supercritical fluids was already suggested [2] and subsequently extensively applied to different supercritical fluid processes [63]. The solubility y>2 is then expressed as ... 

Brennecke, J. F. Eckert, C. A. Phase Equilibria for Supercritical Fluid Process Design. AIChEJ. 1989, 35, 1409-1427. 

Rizvi, S.S.H., Bhaskar, A.R. 1995. Supercritical fluid processing of milk fat Fractionation, scale-up, and economics. Food Technol. 49, 90-100. 

A new supercritical fluid process has been developed for the continuous extraction of liquids. The most useful solvent employed in the recently patented process is supercritical or near-critical carbon dioxide(l). At the heart of the process are porous membranes. Their porosity combined with a near-critical fluid s high diffusivity create a dynamic non-dispersive contact between solvent and feed liquid. The technique is dubbed porocritical fluid extraction and will be commercialized as the Porocrit Process. 

Research with Modular Laboratory and Pilot Equipment in the Field of Supercritical Fluid Processing... 

Since the products and the process steps to which a supercritical fluid process could be successfully applicable are widespread, the demand for high pressure pilot units to check the feasibility arose first of all in the field of Supercritical Fluid Extraction (SFE). 

Ribeiro Dos Santos, I., Richard, J., Pech, B., Thies, C., and Benoit, J. P. (2002), Microencapsulation of protein particles within hpids using a novel supercritical fluid process, Int. J. Pharm., 242, 69-78. 

The use of supercritical fluid processing technology has also been widely used for its application in controlled microparticle formation. Conventional small molecules and proteins for inhalation have been generated and formulated as powders for inhalation. [183-186],... 

The mixed-crystal system formed by indomethacin and saccharin (l,2-benzisothiazol-3(2H)-one-l,1-dioxide) has been used to evaluate the feasibility of using supercritical fluids as media for the design and preparation of new cocrystals [44]. In this work, the relative merits of supercritical fluid processes (i.e., cocrystallization with a supercritical solvent, supercritical fluid as anti-solvent, and the atomization and anti-solvent technique) were evaluated, as well as the influence of processing parameters on product formation and particle properties of the yields. It was reported that while the anti-solvent and atomization procedures yielded pure cocrystal products, only partial to no cocrystal formation took place when using the crystallization process. 

In addition to the process benefits, there are cost and environmental benefits associated with the supercritical process. The supercritical fluid process has low operating energy costs when compared to other alternative solvent processes and the cost of the carbon dioxide used to supply the system is orders of magnitude less than the purchase costs of chlorofluorocarbons, especially with the added taxes imposed by the federal government. In addition, carbon dioxide is a more environmentally friendly material and does not have the disposal costs associated with other alternatives. 

The initial equipment costs and operating costs for the more conventional processes are higher than for supercritical carbon dioxide. The higher equipment costs are due to the additional parts needed for environmental treatments (i.e., scrubbers, vapor incinerators, etc.) The consumables costs are lower for the supercritical fluid processes due to the closed-loop recycle design of the supercritical fluid system, elimination of water for rinsing and the reduced electricity costs associated with not having to dry the parts. 

For the two cases we studied, supercritical fluid cleaning processes resulted in a lower cost of ownership. This cannot be generalized to all processes, but it does indicate that the overall operational costs of supercritical fluid processes can be competitive with other cleaning processes. 

K. Nakamura, in S. S. H. Rizvi, ed.. Supercritical Fluid Processing of Food and Biomaterials, Blackie Academic Professional, London, 1994, p. 54. 

Sarrade S, Guizard C, and Rios GM. New applications of supercritical fluids and supercritical fluids processes in separation. Sep. Purif. Technol. 2003 32(l-3) 57-63. 

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