DRYING DYNAMICS OF MICROALGAE (Chlorella pyrenoidosa) DISPERSION DROPLETS

Publication date: Available online 11 March 2019Source: Chemical Engineering and Processing - Process IntensificationAuthor(s): Ana Paula Biz, Lúcio Cardozo-Filho, Everton Fernando ZanoeloAbstractSpray drying of microalgae is believed to reduce the high cost of energy, and the low yield of extraction that typically make it prohibitive to produce commercially lipids from microalgae. In this framework, the primary aim of this study was to investigate the drying kinetics of droplets that mimic the ones formed during spray drying of microalgae dispersions. Drying of a set of one hundred, equal in size droplets of distilled water on a hydrophobic surface was investigated under different temperatures and air velocities. The kinetics of mass loss was described by two conservation equations solved by the BDF numerical method, with convective coefficients tuned on the kinetic results by the Simplex method of optimization. Drying experiments with each dispersion droplet containing approximately nine to ten thousand spherical particles of microalgae were also performed. The period of drying governed by convection was again properly described by energy and water mass balances without involving any further adjustable parameter. The water transfer through the microalgae was correctly represented by the analytical solution of the Fick's second law for a sphere with negligible external resistances to mass transfer, and a tuned diffusivity of 1.4 × 10―13 m2 s―1.Graphical abstract

Source: Chemical Engineering and Processing: Process Intensification - March 12, 2019 Category: Chemistry Source Type: research