caa a22 4500 463163141 CHVBK 20180406164753.0 cr unu---uuuuu 170326e20070101xx s 000 0 eng 10.1007/s11242-006-9015-1 doi (NATIONALLICENCE)springer-10.1007/s11242-006-9015-1 Modeling of vacuum desorption of multicomponent moisture in freeze drying [Elektronische Daten] [J. Nastaj, B. Ambrożek] A mathematical model of multicomponent vacuum desorption, which occurs in the vacuum freeze drying process has been developed. Drying with conductive heating and constant contact surface temperature was considered. Pressure drop in the layer of the material to be dried was taken into account in the model formulation and process simulation. Equilibrium moisture content for pure water, toluene, and m-xylene and their two- and three-component mixtures on zeolite DAY 20F were described by means of the multitemperature extended Langmuir isotherm equation. Model equations were solved by the numerical method of lines. Moisture content and temperature distributions within the drying material were predicted from the model as a function of drying time. Springer Science+Business Media B.V., 2006 Vacuum desorption nationallicence Freeze drying nationallicence Multicomponent moisture nationallicence Zeolite DAY F20 nationallicence a e : Effective thermal diffusivity, m2/s nationallicence a i : Constant of multitemperature Langmuir isotherm of component i, K nationallicence b i : Constant of multitemperature Langmuir isotherm of component i, Pa−1 nationallicence c a i : Specific heat of component i in adsorbed phase, J/(kg K) nationallicence c pg i : Specific heat of component i in gas (vapor) phase, J/(mol K) nationallicence c i : Constant of multitemperature Langmuir isotherm of component i, K nationallicence c s : Specific heat of adsorbent, J/(kg K) nationallicence C : Molar gas density, mol/m3 nationallicence C i 0 : Initial molar concentration of component i in the gaseous phase, mol/m3 nationallicence C i * : Dimensionless molar concentration of component i in the gas phase nationallicence d p : Particle diameter, m nationallicence D eff i : Effective diffusion coefficient of component i, m2/s nationallicence D K i : Knudsen diffusion coefficient of component i, m2/s nationallicence D S i : Surface diffusion coefficient of component i, m2/s nationallicence Δ H i : Heat of adsorption of component i, J/mol nationallicence J z : Mass flux density, mol/(m2 s) nationallicence k e : Effective thermal conductivity of adsorbent bed, W/(mK) nationallicence k D : Permeability of porous media (m2) nationallicence k E : Parameter describing the inertial effect in Ergun's equation (m) nationallicence K i : Kinetic coefficient of component i, 1/s nationallicence L : Dried layer thickness, m nationallicence M i : Molecular weight of component i, kg/mol nationallicence N : Number of sections of drying material layer nationallicence p i : Partial pressure of component i, Pa nationallicence Δ P : Reference pressure variation for normalization, Pa nationallicence P : Total pressure, Pa nationallicence X avg i : Average moisture content of component i (dry basis), kg i/kg nationallicence X i : Moisture content of component i (dry basis), kg i/kg nationallicence X i * : Equilibrium moisture content of component i (dry basis), kg i/kg nationallicence y i : Mole fraction of component i in the gas phase, mol i/mol nationallicence t : Time, s nationallicence Δ T : Reference temperature variation for normalization, K nationallicence T : Temperature, K nationallicence T i : Initial temperature of drying layer, K nationallicence T0 : Contact surface temperature, K nationallicence y i : Mole fraction of component i, mol i/mol nationallicence z : Axial coordinate, m nationallicence Z : Dimensionless axial coordinate nationallicence Greek symbols nationallicence ε : Bed void fraction nationallicence ε p : Particle porosity nationallicence μ : Viscosity of gas mixture, Pa s nationallicence ω : Normalized pressure nationallicence θ : Normalized temperature nationallicence Ω i : Dimensionless concentration of component i in solid phase nationallicence ρ p : Particle density of adsorbent, kg/m3 nationallicence ρ b : Bulk density of adsorbent, kg/m3 nationallicence τ : Dimensionless time nationallicence Acronyms nationallicence VC : Vacuum chamber nationallicence LDF : Linear driving force nationallicence Nastaj J. Department of Chemical Engineering and Environmental Protection Processes, Szczecin University of Technology, Al. Piastów 42, 71-065, Szczecin, Poland aut Ambrożek B. Department of Chemical Engineering and Environmental Protection Processes, Szczecin University of Technology, Al. Piastów 42, 71-065, Szczecin, Poland aut Transport in Porous Media Kluwer Academic Publishers 66/1-2(2007-01-01), 201-218 0169-3913 66:1-2<201 2007 66 11242 https://doi.org/10.1007/s11242-006-9015-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11242-006-9015-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Nastaj J. Department of Chemical Engineering and Environmental Protection Processes, Szczecin University of Technology, Al. Piastów 42, 71-065, Szczecin, Poland aut NATIONALLICENCE 700 1- Ambrożek B. Department of Chemical Engineering and Environmental Protection Processes, Szczecin University of Technology, Al. Piastów 42, 71-065, Szczecin, Poland aut NATIONALLICENCE 773 0- Transport in Porous Media Kluwer Academic Publishers 66/1-2(2007-01-01), 201-218 0169-3913 66:1-2<201 2007 66 11242 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer