Publisher DOI: 10.1016/j.supflu.2018.07.002
Title: Model development for sc-drying kinetics of aerogels: Part 1. Monoliths and single particles
Language: English
Authors: Selmer, Ilka 
Behnecke, Anna Sophia 
Quiño, Jaypee 
Braeuer, Andreas Siegfried 
Gurikov, Pavel 
Smirnova, Irina 
Issue Date: Oct-2018
Source: Journal of Supercritical Fluids (140): 415-430 (2018-10)
Journal or Series Name: The journal of supercritical fluids 
Abstract (english): A mass transport model for the supercritical drying of gels to aerogels in different sizes (monoliths or particles) and shapes (cylinder, sphere) was developed and evaluated. Physico-chemical data for the system CO2/ethanol from literature at relevant process conditions were analyzed for a precise description of relevant physical properties. In situ measurements of the supercritical drying kinetics of gel monoliths using Raman spectroscopy were used to fit the tortuosity factor of the gel network. Apart from the fitted tortuosity factor the presented model is predictive. The model was analyzed in detail for the case of spherical gel particles. Theoretical minimal drying times were found to range in seconds for microparticles. The mass transfer step limiting the overall drying kinetics was analyzed using the dimensionless Biot number. The transition Biot number can be used for rational selection of the drying conditions (pressure, temperature, mass flow) to achieve a fast drying with low CO2 consumption.
URI: http://hdl.handle.net/11420/2413
ISSN: 0896-8446
Institute: Thermische Verfahrenstechnik V-8 
Type: (wissenschaftlicher) Artikel
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