Application of supercritical fluid processes

Abstract

The present work deals with the storage of Hydrogen where promising ways are based on the solubility of organic or inorganic compounds in supercritical fluids, inducing specific interactions to retain this non polluting energy vector.Consequently the modeling of the solubility of polar organic compounds like Ortho Hydroxy benzoic acid (o-HBA), and Para Hydroxy benzoic acid (p-HBA), Dichloro diphenyl Trichloro ethane (DDT) and 2,4-Dichloro phenoxyacetic acid (usually referred to by its abbreviation, (2,4-D) as well as their mixtures, in supercritical fluids such as carbon dioxide, is presented.For the two binary systems i.e. o-HBA-CO2, DDT-CO2 the model combining the cubic Redlich Kwong (RK) equation of state (EOS) with the van der Walls (VW) mixing rule (MR) at constant temperature of 313 K and a pressure range of 120–220bar, showed quite good results compared to the experimental values. However the model Redlich–Kwong–Soave (RKS)–Wong–Sandler (WS) provided a better correlation.Similarly the model RK-WS gave better results for the solubility of o-HBA in CO2 and for the mixture o-HBA–2,4-D in CO2.The obtained solubilities of p-HBA in supercritical carbon dioxide were found to be higher than that of o-HBA. This can be explained by the differences in the intermolecular interactions which are relatively weak for the case of o-HBA.The results obtained from the combinations Patel–Teja (PT)-VW and PT-WS showed important deviations compared to the experimental values and this for all the considered systems.