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Phase equilibria and process simulation for high-pressure supercritical extraction processes


To improve the understanding of low energy extraction processes which use supercritical carbon dioxide (SCD) or supercritical solvents (SCS).

SCD or SCS extraction methods can be used for recovering or separating organic chemical products from aqueous solutions. The energy savings of these new techniques as compared to distillation can be more than 50%. They have large fields of application (e.g. downstream processing of fermentation broths to extract ethanol, acetone, butanol) and could also be important for the production of fuels such as methanol and ethanol.

The research was divided in three parts: experimental, modelling and process simulation. The experimental part focused on measurements of phase equilibria in synthetic mixtures, containing a supercritical solvent, water and an organic compound (e.g. ethanol, propanol, butanol, acetic acid). Extraction of organic chemicals from a fermentation broth were also be carried out. Experimental data were then correlated using a non predictive model (UDLA, University of Cadiz). A generalized model for the prediction of phase equilibria in mixtures containing a supercritical solvent and polar compounds were also developed by DTH. This model is an extension of the well established UNIFAC group contribution model. DTH integrated the developed models in steady state and dynamic process simulation computer codes (SEPSIM and DYNSIM) for the study of energy efficiency and system control of supercritical extraction processes.

In order to ensure technology transfer from the research laboratory into industry, an industrial consortium was formed. Fifteen companies such as Shell, BP, ICI, IFP, ENI, Linde, DSM participated. These companies advised on the project and provided feedback to improve final results. Pilot plant tests obtained with the mixture water-alcohol showed that energy saving of 20 % can be obtained.

Funding Scheme

CSC - Cost-sharing contracts


Danmarks Tekniske Universitet

2800 Build Lyngby

Participants (1)

Monteluco Di Roio
67040 L'aquila