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Design of a packed column for ethanol extraction. Equilibrium and kinetics studies
Author(s) -
Ismael R. Costa,
De Carvalho J. M. Rodrigues,
Dias S. M. Martins,
Novais J. Maggiolly
Publication year - 1994
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.270170609
Subject(s) - chemistry , packed bed , mass transfer , thermodynamics , diffusion , chromatography , volume (thermodynamics) , kinetics , solvent , drop (telecommunication) , analytical chemistry (journal) , organic chemistry , telecommunications , physics , quantum mechanics , computer science
Abstract Computer‐aided design of a packed column to remove ethanol from aqueous solution with dibutyl butylphosphonate (DBBP) was accomplished with a programme based on the Pratt method and on the slip velocity equation. Reliable data for successful computation were obtained from literature correlations (drop size, hold‐up and axial mixing coefficients for different types of packing) and from experimental work (equilibria and kinetics). Equilibrium studies on the H 2 O‐ethanol‐dibutyl butylphosphonate system were performed at different temperatures. A decrease in temperature increased the selectivity of the extractant while the distribution coefficient of ethanol, K D ≈ 1.0, remained constant. The behaviour of the system kinetics towards temperature is assessed in order to determine the initial mass transfer flux (892 × 10 −3 kg m −2 s −1 , 30°C) and the activation energy, 22.9 kJ/kmol. The process is governed by the diffusion of the species involved. The influence of the type of packing of the column on its design is analyzed from the inventory volume of the solvent, the total volume of the column and the axial dispersion coefficients under normalised inlet and outlet conditions.