Investigation of thermodynamic behavior on rapid expansion of Supercritical solution

فاقد چكيده فارسي

Rapid expansion of supercritical solutions, which can be obtained by using a throttling device, occurs in a very short time (less than 1μs). It leads to appreciable supersaturation and uniform conditions within the expanding fluid. The information about the thermodynamic behavior of supercritical solutions is one of the fundamentals for modeling processes, such as the formation of small particles by RESS process. RESS allows the production of particles less than 1 mm and RESS experiments show that particle size depends on solvent, solute and pre-expansion conditions. However, an understanding of the underlying physical phenomena of the relationship between the process conditions and the mechanism of particle formation during RESS is still at an early stage. Because of that, there is a need to model the RESS process to get a better understanding of the influencing parameters. The calculations show a steep increase at the beginning of the free jet reaching maximum theoretical supersaturation of 105. In the this study, the influence of the solubility of benzoic acid in supercritical carbon dioxide and trifluoromethane on attainable supersaturation rates under typical RESS operation conditions is investigated.