Gas-phase controlled convective drying of solids wetted with multicomponent liquid mixtures
1991 (English)In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 46, no 9, 2235-2252 p.Article in journal (Refereed) Published
The nonisothermal convective drying of an impermeable solid substrate covered with multicomponent solvent mixtures was studied. The aim was to simulate the nonsteady-state evaporation process under the control of the gas side heat and mass transfer. Diffusional resistances in the liquid layer were prevented by choosing conditions providing low evaporation rates. Evaporation fluxes were calculated by assuming either interactive or independent diffusion through the gaseous boundary layer. The interactive effects were accounted for by applying the linearized theory of Toor. Independent fluxes were calculated using the effective diffusivity method. In the experimental part, a Teflon substrate wetted with the binary mixture acetone—methanol, the ternary mixture ethanol—methylethylketone—toluene and the quaternary mixture ethanol—methanol—acetone—chloroform was dried using air flowing parallel to the evaporation surface as drying agent. Good agreement was obtained between experiments and simulations. Calculations show that liquid composition, liquid temperature, gas composition and diffusional interactions have a significant influence on the instantaneous selectivity while the effect of gas temperature and gas velocity is less important. Selectivity can be controlled by using a gas preloaded with an appropriate composition. The model can be applied to the drying, at an initial stage, of coated laminates with a gentle drying regime.
Place, publisher, year, edition, pages
1991. Vol. 46, no 9, 2235-2252 p.
IdentifiersURN: urn:nbn:se:kth:diva-102097DOI: 10.1016/0009-2509(91)85123-FOAI: oai:DiVA.org:kth-102097DiVA: diva2:550816
NR 201408052012-09-082012-09-082012-09-08Bibliographically approved