Simulation of a supercritical carbon dioxide extraction plant with three extraction vessels (original) (raw)
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Dynamic model of a supercritical fluid extraction plant
AIChE Journal, 2007
A dynamic model of a supercritical fluid extraction (SFE) process was developed and applied to the fractionation of the binary mixture squalene/methyl oleate by supercritical carbon dioxide. The model combines a mathematical model for each main piece of equipment of the SFE process, namely, the countercurrent packed extraction column, the separation column for oil recovery and solvent regeneration, the heat exchanger for heating fresh CO 2 , and the make-up of solvent in the process plant. Experimental tests were performed in a pilot-plant SFE apparatus where perturbations on prespecified operating parameters were induced and their effect on main process variables determined. A good agreement was obtained between experimental and predicted results. In addition, the dynamic model of the packed extraction column was applied to other SFE case studies where sufficient experimental data is available. The dynamic model was found to correctly predict the outlet streams composition profiles of all the case studies.
Numerical Simulation of Supercritical Extraction Processes
Chemical Product and Process Modeling, 2009
A mathematical model with two different methods to represent the mass transfer in the biomass matrix, (series and parallel) is proposed to simulate a supercritical extraction unit. The model is solved using the method of lines and finite differences with flow correction. Using experimental extraction curves, both models were fitted fairly well, with equivalent accuracy. Two operating regimes were detected in the selected experimental conditions: equilibrium and mass transfer controlled. The last one is more difficult to simulate, requiring specific mass transfer parameters for series and parallel alternatives, for its accurate representation.
2018
In supercritical CO2 extraction process , there are two essential steps: the extraction step in the extractor where the SC-CO2 allows the solvent or extract removal from product structure and the separation step which consists of the separation of CO2-solvents or CO2-extract in a cascade of cyclone separators downstream the extractor. Cyclone separators are separation devices that use the centrifugal and gravity forces to remove liquid phase from flue gases. Two supercritical extraction processes are studied here: organogels supercritical drying for aerogels production and supercritical extraction of polar compounds from natural products. Concerning the first process, the organogel is prepared by an aminoacid-type organogelator with aromatic solvents such as tetralin or toluene. The experimental results showed a good solvent recovery rate in the case of tetralin, exceeding 90% but an unsatisfactory separation for toluene with a yield below 65%. In order to understand the experimenta...
Sensitivity analysis and operative conditions of a supercritical fluid extractor
The Journal of Supercritical Fluids, 2007
In this paper, a typical analysis of the effect of model uncertainties on predictions is extended to a supercritical extraction process for an extractor feed by vegetable seeds and utilizing supercritical CO 2 as solvent. The sensitivity analysis reveals that two parameters are particularly important for the extraction process modeling: the particle diameter and the internal mass transfer coefficient. Therefore, a deeper analysis of the sensitivity of these two parameters has been performed: the sensitivity depends on the length of the process. In the supercritical extraction process, two successive phases can be considered: the former is controlled by the solubility of the oil in the supercritical solvent, and it is therefore almost completely insensitive; the second phase, on the contrary, is mainly controlled by internal transport phenomena and it is very sensitive to the above mentioned parameters. The effect of changing some operative conditions is also investigated, underlining how the solvent flow rate and the seed milling affect the extraction process. From these results, an extraction procedure is proposed that would reduce the solvent consumption without resorting to the connection in series of several extractors.
2015
Supercritical fluid extraction (SFE) of vegetable oils is an alternative method to organic solvent (namely hexane) and mechanical extraction. To exploit the SFE technology at industrial scale, the process has to be optimized. An effective way to perform optimization is to resort to models that are capable to describe and simulate the SFE process. Plenty of models are available in the literature concerning the SFE of vegetable oils. Modeling the process in a semi-continuous extraction column (the bed of matrix to be extracted is stationary, the supercritical fluid moves continuously through it) requires an equipment model, the column model, and a particle model accounting for mass transfer mechanisms. Column models are quite established. Thus, to achieve a satisfactory description of the process, having a very effective particle model seems the key-point. In this work the SFE kinetics of seed oil (namely: grape seed oil) was modeled using different particle models: the broken and int...
The Effect of Fluid Flow Rate and Extraction Time in Supercritical Carbon Dioxide
2019
1 Centre of Lipid Engineering and Applied Research (CLEAR), Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia 2 Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia 3 Department of Chemical Engineering, Universiti Teknologi Petronas, 32610 Bandar Sri Iskandar, Perak, Malaysia
To allow an easy individuation of the more suitable working conditions (temperature, pressure, flow rate, etc.) to be adopted to carry out the extraction of food grade oils from different substrates by supercritical CO 2 (Sc-CO 2), a simplified kinetic approach has been introduced. This kinetic model was utilised to describe supercritical fluid extraction (SFE) of oil by Sc-CO 2 not only from seeds (sunflower, soybean and rape) but also from microalgae (Nannochloropsis sp., Schizochytrium sp. and Spirulina (Arthrospira) platensis) characterised by a lipid fraction with a high proportion of polyunsatured fatty acids (C20:5ω-3; C22:6ω-3; C18:3ω-6). Thanks to the high affinity occurring between oil and Sc-CO 2 it was possible to introduce a simplified kinetic model able to describe the time evolution of oil extraction from substrates which deeply differ for biochemical and biophysical characteristics. Moreover the synergistic utilisation of the kinetic model introduced and of the Chrastil's equation, allowed to predict the time evolution of oil extraction as a function of the: substrate used; amount of its fat content; mass of substrate charged inside the extractor; possible pre-treatments carried out on the used substrate; flow rate of Sc-CO 2 ; working conditions adopted (temperature, pressure and then Sc-CO 2 density).
American Journal of Analytical Chemistry, 2012
To allow an easy individuation of the more suitable working conditions (temperature, pressure, flow rate, etc.) to be adopted to carry out the extraction of food grade oils from different substrates by supercritical CO 2 (Sc-CO 2 ), a simplified kinetic approach has been introduced. This kinetic model was utilised to describe supercritical fluid extraction (SFE) of oil by Sc-CO 2 not only from seeds (sunflower, soybean and rape) but also from microalgae (Nannochloropsis sp., Schizochytrium sp. and Spirulina (Arthrospira) platensis) characterised by a lipid fraction with a high proportion of polyunsatured fatty acids (C20:5ω-3; C22:6ω-3; C18:3ω-6). Thanks to the high affinity occurring between oil and ScCO 2 it was possible to introduce a simplified kinetic model able to describe the time evolution of oil extraction from substrates which deeply differ for biochemical and biophysical characteristics. Moreover the synergistic utilisation of the kinetic model introduced and of the Chrastil's equation, allowed to predict the time evolution of oil extraction as a function of the: substrate used; amount of its fat content; mass of substrate charged inside the extractor; possible pretreatments carried out on the used substrate; flow rate of ScCO 2 ; working conditions adopted (temperature, pressure and then ScCO 2 density).
Modelling of a New Supercritical Fluid Extraction Process for Palm Oil Refining
This work describes the modelling of a new supercritical fluid extraction (SFE) process for palm oil refining. The aim is to develop the new, intensified and simpler palm oil refining process that is based on SFE technology that can overcome the limitations of the existing technology for palm oil refining. Two steps approach were used. Firstly, the phase equilibrium behavior of the crude palm oil (CPO)-supercritical CO2 mixture was developed. Secondly, a new flowsheet structure was synthesised to recover high purity palm oil which includes its minor components. The SFE process to recover high nutritional value palm oil was finally simulated using Aspen Plus ® commercial process simulator version 10.2.1 based on the Redlich-Kwong-Aspen (RKA) thermodynamic model. The results obtained were in good agreement with the pilot plant data reported in literature.
The Journal of Supercritical Fluids, 2007
A mathematical model for the fractionation of liquids with supercritical CO 2 in a countercurrent packed column is presented. This model is based on the differential mass and energy balances over the height of the extractor, which are solved numerically. The phase behavior of the multicomponent systems of interest for this process is represented with the Peng-Robinson Equation of State. Volumetric and thermal properties of the fluids are also calculated with the PR-EOS. Transport properties are estimated applying suitable correlations. This model includes the coupled mass and heat transfer in the interface between the two fluid phases. Since the model includes the energy balance, it is possible to study the operation with a gradient of temperature over the height of the extractor. The model has been validated comparing the predictions with experimental data for the fractionation of edible oil mixtures and the separation of fish oil ethyl esters taken from the literature. The correlation between experimental and calculated results is reasonably good, and the model predicts correctly the trends of variation with the different operating and design parameters.