Construction and Validation of an Online Subcritical Adsorption-based Device for Assisting CO2 Recycling during a Supercritical Fluid Extraction Process

R. Abel C. Torres, Diego T. Santos, M. Angela A. Meireles*
LASEFI/DEA/FEA School of Food Engineering/UNICAMP University of Campinas, R. Monteiro Lobato, 80; 13083-862, Campinas, SP, Brazil

© 2018 Torres et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the LASEFI/DEA/FEA (School of Food Engineering)/UNICAMP (University of Campinas), CEP 13083-862, Campinas, SP, Brazil; Tel: +55 19 35210100; E-mail:



An efficient process for extracting food ingredients from plant materials should demand the use of a reduced volume of extraction solvent to obtain a final product that is free of solvent and reduces both the processing time and the costs. In some cases, achieving a new efficient process requires the modification, reconfiguration or renewal of elements that are part of a processing unit.


The goal of this work is to describe the development of a modification of a commercial supercritical fluid extraction pilot unit designed to assist CO2 recycling based on subcritical adsorption on an adsorbent material. In addition to the construction and validation of the system, a cost survey was performed to estimate the cost of the homemade device developed to allow effective CO2 recycling.


The developed device was tested using cotton and Celite® as model adsorption materials and annatto seeds (Bixa orellana L.) as a model plant material. A 0.65 L adsorption column was installed with a set of connections and valves that complemented the unit’s recycle system. The validation procedure consisted of defatting annatto seeds.


The proposed online subcritical adsorption-based device was technically validated using cotton as an adsorbent material. The cost survey showed that an estimated total cost of USD 5731.36 would be required to install the developed device in a Supercritical Fluid Extraction (SFE) unit similar to the one coupled here (5 L).


The proposed device was demonstrated to be very promising for application in the pseudocontinuous SFE, recirculating the same amount of CO2 mass exceeding the S/F values by 14 times, when compared to a process without a CO2 recycling system.

Keywords: Bixa orellana L, CO2 recycle, Online coupling, Plant extracts, SFE, Supercritical CO2.