Separation of submicron particles in packed columns optimization and scale-up of the process

Abstract

Particle enlargement by heterogeneous condensation and - based on it - separation of submicron particles in packed columns of technical scale are investigated. The activation of submicron particles and droplet growth by heterogeneous condensation is briefly described. Calculations of the droplet growth are performed and compared with experimental results. The enlargement and the separation of submicron particles by cascading packed columns trickled with water which is alternately colder or warmer than the gas is experimentally studied in a technical scale pilot plant consisting of three packed columns with a diameter of 300 mm. Droplet size distributions are measured by means of an optical particle sizer at the outlet of the columns. In order to optimize the separation process, the influence of different parameters on the separation of the submicron particles is investigated. These are the gas and the water temperature, the gas and the water flow rate, and the particle concentration. Moreover, the supersaturation of the air stream in the column is calculated by means of a rate-based nonequilibrium process model as a function of different parameters. © WILEY-VCH Verlag GmbH, 1999.