Review of some common commercial and noncommercial lab-scale spray dryers and preliminary tests for a prototype new spray dryer

ABSTRACT

This paper has briefly introduced the problem of wall deposition in the spray drying process and some factors related to wall deposition. A short review of some commercial and noncommercial spray dryers has also been discussed. Based on the review, a spray drying system featured with a flexible chamber design has been proposed. Results of preliminary nonspraying and water spraying tests have been briefly discussed. The results have indicated that the equipment has been operated with an acceptable evaporative performance (with an evaporative intensity of around 30 kg/h · m³). Spraying tests using 10 and 8.8 wt% salt solutions, as well as 8.8 wt% skim milk powder solution, have achieved a recovery rate of around 70%, with small amounts of wall deposition observed in the drying chamber (around 7% of the total dried solids) and the cyclone. The experimental results have shown that the proposed system had a reasonable evaporative capacity in comparison with models of similar sizes, and that the system appears to have some potential for lowering the deposition rates.

KEYWORDS:

• Chamber design
• computational fluid dynamics
• spray drying

Acknowledgments

Scholarship support from the Australian Research Council Industrial Transformation Training Centre for the Australian Food Processing Industry in the 21st Century and Lang Technologies P/L is gratefully acknowledged for this work.