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- Modelling the kinetics of supercritical CO2 extraction of biomassPublication . R. M. Filipe; Coelho, Jose; Robalo, Maria Paula; Cholakov, Georgi; Stateva, R. P.This work addresses the modelling and simulation of the kinetics of CO2 supercritical extraction of oils from biomass. Experimental and simulation results from different matrices and models are presented. gPROMS Model Builder is used to find solutions to three different models applied to study the extraction of three different volatile oils from aromatic plants (coriander, fennel and savoury), and from a bioresidue, industrial grape seeds. The supercritical extraction experiments performed at different temperature, pressure and flow rate conditions provide the data to the modelling studies and for model parameter estimation. The qualitative and quantitative agreement between the experimental and simulated extraction profiles in terms of yields was good for the cases investigated.
- Influence of co-solvents on the supercritical extraction kinetics of spent coffee grounds: experimental and modelling studiesPublication . Coelho, Jose; Filipe, Rui; Robalo, Maria Paula; Boyadzieva, Stanislava S.; Cholakov, Georgi; Stateva, Roumiana P.Coffee is one of the most widely used beverages. An estimated 3.5 billion cups of coffee are drunk worldwide every day. In EU alone, for the period 2011-2013, 2.5 Mt of coffee were consumed. Taking into consideration that the production of coffee in 2015 was approximately 9 Mt and that from each kg of coffee 0.91 kg of solid waste is produced, the importance of a further valorization of this residue becomes obvious. In recent years, the biorefinery concept has been identified as the most promising route for employment of the full potential of a biomass by maximizing its conversion into high value products. Its main bottleneck, however, is how to extract the energy and non- energy compounds from the biomass without damaging one or more of the components, e.g. those which are heat sensitive. Spent coffee grounds (SCGs) contain large amounts of fatty acids, lignin, cellulose, hemicellulose, etc. and can be exploited as an excellent source of value-added energy and non-energy related products (e.g, antioxidants and other functional additives).
- Supercritical CO2 extraction of feed stocks to generate high added value bio-productsPublication . Coelho, Jose; Boyadjieva, S.; R. M. Filipe; Robalo, Maria Paula; Cholakov, Georgi; Stateva, R. P.The huge amounts of waste generated every year by the industry, in addition to the great loss of valuable materials, pose serious organisational problems, both from an economic and ecological point of view. Many of the residues, however, have the potential to be reused and utilized completely via integrated bio-refining technologies. Extraction techniques which play a very important part in biorefineries should provide swift processing and yield quantitative recovery without degradation, complemented by easy separation of extracts from the solvent. In this work, focussed on two generic biomass examples - grape seeds and spent coffee grounds, we outline the perspectives of introducing mild, efficient and with low environmental impact techniques that apply compressed fluids in biorefineries for obtaining high value-added products with a wide spectrum of applications.