Counter-current spray drying with stream separation: Computational modeling of a noveldryer design
Journal article, 2015

Spray drying has been in use for producing fine powder of pharmaceuticals in order to make the drug respirable and thus accessible to the large absorptive area of the lungs. However, traditional designs for spray dryers have turned out to be inappropriate for processing very fine particles. Therefore, a novel design has been suggested in which the drying agent is separated from the moisture-containing material by using a vapor-permeable membrane (Gerde, 2009). A computational model of the new design has been developed for design and optimization purposes. The model has been shown to satisfactorily reproduce the experimental measurements. A linear correlation has been obtained between the swirl flow rate and the outflow concentrations, predicting a maximum possible flow rate of1 L/min in order to meet the required quality of the product. The performance of the dryer has been shown to be very sensitive to the injection flow rate as well as the effective diffusivity of the membrane. Using ethanol as the solvent,the model predicts a maximum injection of 12 mg/min. Based on the simulation results, a fairly low probability of wall deposition is expected.

Respiratory drug delivery

Swirl-stabilized injection

Computational modelling


Membrane separation

Spray drying


Soheil Soltani

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Chemical Reaction Engineering

Competence Centre for Catalysis (KCK)

Per Gerde

Inhalation Sciences Sweden AB

Fernando Acevedo

Inhalation Sciences Sweden AB

Anders Rasmuson

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Chemical Environmental Science

Chemical Engineering Research and Design

0263-8762 (ISSN) 1744-3563 (eISSN)

Vol. 93 163-173

Areas of Advance



Materials Science

Subject Categories

Chemical Process Engineering

Driving Forces

Innovation and entrepreneurship



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