caa a22 4500 46316329X CHVBK 20180406164754.0 cr unu---uuuuu 170326e20070101xx s 000 0 eng 10.1007/s11242-006-9016-0 doi (NATIONALLICENCE)springer-10.1007/s11242-006-9016-0 Optimization of Fine Solid Drying in Bubble Fluidized Bed [Elektronische Daten] [Artur Poświata, Zbigniew Szwast] A commonly used method to dry fine solid particles is drying in a fluidized bed. This paper presents the optimization problem of fluidized drying of fine solids. A drying process proceeding in a three-stage cascade of fluidized cross-current dryers was considered. Solid flows from stage to stage, and fresh gas is introduced to each stage of the cascade. The hydrodynamics of bubble fluidized bed and kinetics of heat and mass transfer are taken into account. The bed hydrodynamics is described by a two-phase model. The drying process considered proceeds in the second period of drying. To optimize this problem a generalized version of a discrete algorithm with constant Hamiltonian was used. The optimization procedure is presented in the paper. In optimization calculations, gas parameters (temperature, humidity and flow rate) minimizing total process cost are sought. The results of calculation are presented as graphs. The results obtained and the conclusions drawn are discussed. Springer Science+Business Media B.V., 2006 Fluidized drying nationallicence Drying optimization nationallicence Exergy minimizing nationallicence Hamiltonian nationallicence Optimization algorithm nationallicence A , B : Coefficients in performance index, kJ/(kg K2),kJ/kg nationallicence c g : Gas specific heat , kJ/(kg K) nationallicence G : Gas mass flow rate, kg/s nationallicence h : Solid enthalpy, kJ/kg nationallicence h mf : Bed height in minimum fluidization, m nationallicence i : Gas enthalpy, kJ/kg nationallicence i vb : Moisture enthalpy in bubble phase, kJ/kg nationallicence i vmf : Moisture enthalpy in dense phase, kJ/kg nationallicence K : Drying constant, 1/s nationallicence k b : Mass transfer coefficient between dense and bubble phase, kg/m3 nationallicence S : Solid mass flow rate, kg/s nationallicence S v : Volume solid flow rate, m3/s nationallicence T : Temperature,°C, K nationallicence u g : Gas superficial velocity, m/s nationallicence u mf : Minimum fluidization velocity, m/s nationallicence u p : Velocity of gas in bubble phase, m/s nationallicence W b : Dimensionless resistance coefficients of mass transfer nationallicence X e : Equilibrium moisture content in solid nationallicence X s : Moisture content in solid nationallicence Y : Moisture content in gas nationallicence Z b : Dimensionless resistance coefficients of heat transfer between gas and solid nationallicence Z mf : Dimensionless resistance coefficients of heat transfer between bubble and dense phases nationallicence Greek symbols nationallicence αb : Heat transfer coefficient between dense and bubble phase, kJ/m3K nationallicence αmf : Heat transfer coefficient between solid and gas, kJ/m3K nationallicence κ : Exergy coefficient of investment and gas pumping costs, kJ/kg nationallicence ρ : Density, kg/m3 nationallicence ζ : Ratio of chemical exergy unit price to thermal exergy unit price nationallicence τ : Average solid hold-up, s nationallicence σ : Volume fraction of bubble phase in fluidized bed nationallicence θg : Dimensionless gas flow rate (ratio of gas mass flow rate to solid one) nationallicence σg : Mass fraction of gas flowing through bubble nationallicence ɛmf : Dense phase porosity nationallicence Subscripts nationallicence b : Outlet gas from bubble phase nationallicence g : Inlet drying gas nationallicence k : Outlet drying gas nationallicence mf : Gas in dense phase nationallicence s : Solid nationallicence Superscripts nationallicence n : Stage number nationallicence Poświata Artur Department of Chemical and Process Engineering, Warsaw University of Technology, Warsaw, Poland aut Szwast Zbigniew Department of Chemical and Process Engineering, Warsaw University of Technology, Warsaw, Poland aut Transport in Porous Media Kluwer Academic Publishers 66/1-2(2007-01-01), 219-231 0169-3913 66:1-2<219 2007 66 11242 https://doi.org/10.1007/s11242-006-9016-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11242-006-9016-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Poświata Artur Department of Chemical and Process Engineering, Warsaw University of Technology, Warsaw, Poland aut NATIONALLICENCE 700 1- Szwast Zbigniew Department of Chemical and Process Engineering, Warsaw University of Technology, Warsaw, Poland aut NATIONALLICENCE 773 0- Transport in Porous Media Kluwer Academic Publishers 66/1-2(2007-01-01), 219-231 0169-3913 66:1-2<219 2007 66 11242 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer