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Extractive Distillation (extractive + distillation)
Selected AbstractsApplication of CAMD in separating hydrocarbons by extractive distillationAICHE JOURNAL, Issue 12 2005Biaohua Chen Abstract The solvent is the core of extractive distillation, and a suitable solvent plays an important role in the economical design of extractive distillation. Computer-aided molecular design (CAMD) has been applied to rapidly screen the solvents for separating hydrocarbons by extractive distillation. The systems of propane/propylene, n-butane/1-butene, and n-heptane/benzene, respectively, as the representatives of C3, C4, and C6 hydrocarbons were investigated, and the potential solvents were selected by means of CAMD. The designed results were further proven by experiments and process simulation. The mechanism for separating hydrocarbons by extractive distillation is based on the different fluidities of the electron cloud of CC (no double bond), CC (one double bond), and ACH (aromatic carbon ring) bonds and thus different interactions between solvent and hydrocarbon molecules. To improve the separation ability of the main solvent, one strategy is to add some additive that can form hydrogen bonding with the main solvent to make into a mixture. © 2005 American Institute of Chemical Engineers AIChE J, 2005 [source] Heterogeneous batch-extractive distillation of minimum boiling azeotropic mixturesAICHE JOURNAL, Issue 12 2003Ivonne Rodríguez Donis Following previous studies on heterogeneous batch azeotropic distillation, the use of heterogeneous entrainers for the separation of binary azeotropic mixtures by extractive distillation is evaluated. This process is well suited for systems where the entrainer forms a saddle heteregeneous azeotrope with any one of the original components, such systems being unsuitable for nonextractive heterogeneous batch-distillation processes. Process feasibility is assessed from the isovolatility curves and the volatility order diagram. It tells us whether the homogeneous original component or the heteroazeotrope is drawn at the column top and establishes the distillation tasks sequence using a batch-rectifying column. The theoretical insights are validated via rigourous simulation for the separation of the acetonitrile,water mixture with hexylamine or butyl acetate. Finally, the same method is applied for the theoretical analysis of a reported industrial example where water is used for the separation of a binary organic mixture, leading to a complex ternary system with several binary azeotropic points and a homogenous ternary azeotrope. [source] Ionic Liquids for Propene-Propane SeparationCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2010V. Mokrushin Abstract This paper presents an extensive study on the feasibility of ionic liquids (IL) for the extractive distillation of propene-propane mixtures. A new experimental method for express screening of non-volatile entrainers was elaborated. A series of ILs and their mixtures were screened at ambient temperature and low pressures. The screening results show that every tested IL turns a low boiler propene into a high boiler and the alkene-to-alkane separation factor can be as low as 0.28. The solubility and separation efficiency can be tuned by adjusting the chemical structures of the ions forming the IL. It was found that shortening of the alkyl substituents of the imidazolium ions leads to a decrease in capacity and to an increase in the separation factor. Interestingly, ILs containing nitrile functionalities in either the cation or the anion showed, in our experiments, enhanced separation ability combined with still good capacities. From our thermodynamic measurements, [EMIM][[B(CN)4] was proved to be the most promising candidate. Binary mixtures of ILs were also tested and resulted in separation factors and capacities between the values for the individual ILs. For the most promising candidates, also autoclave measurements at elevated temperatures and pressures were carried out. These experiments indicate that the separation ability decreases with growing temperature and loading. In general, our study definitely proves the high potential of ILs to act as entrainers in the extractive distillation of propene-propane mixtures or for the separation of any other low-boiling alkene-alkane mixture. [source] | ||||||||||