Laboratory, Pilot Plant and Industrial-Scale Validation of Numerically Optimized Reverse-Flow Gas Cyclones

• Type: Article in International Scientific Journal
• Date: 2004

Authors

Romualdo L. Salcedo (Author) FEUP; Vânia Chibante (Author) FEUP; Isabel Dias Sôro (Author) FEUP

Journal

Title: Filtration

Vol. 4 No. 3

Pages: 220-225

ISSN: 1479-0602

Publisher: Filtration Solutions

Scientific classification

FOS: Engineering and technology > Chemical engineering

Other information

Abstract (EN): This paper addresses the experimental validation of the optimum design of reverse-flow gas-cyclones, obtained through the solution of a numerical non-linear optimization problem, viz. maximizing cyclone collection. The simulation model is based on the predictive properties of a finite diffusivity model, where the particles’ turbulent dispersion coefficient is estimated through an empirical correlation between the radial Peclet and Reynolds numbers. The optimizations were formulated with constraints on pressure drop, saltation velocity and geometrical considerations, such that feasible cyclones could always be obtained. The optimum geometry, named RS_VHE, is different from available highefficiency designs, and represents reverse-flow cyclones with a predicted significantly improved performance. An innovative partial recirculation system within a collector-first arrangement further reduces emissions with only a moderate increase in pressure drop. The generally observed unexpected high collection of submicron particles is attributed to capture by larger particles in the turbulent flow field due to turbulent dispersion, much like what occurs in re-circulating fluidized beds. Results obtained for the RS_VHE cyclones with partial recirculation at laboratory, pilot and industrial scales, for temperatures ranging from 300 to 600 K, gas flow rates from 1 to 104 m3 /h and inlet loads from 15 to 104 mg/m3 , show them to be significantly more performing than equivalent diameter HE cyclones or smaller diameter multi-cyclones. Under certain circumstances, with recirculation the proposed system shows better performance than on-line pulse-jet bag-filters. Overall, the results show that the numerically optimized RS_VHE cyclones, when coupled with a partial recirculation system, open the applicability of these simple devices for fine particle collection which is typical of more expensive devices, such as venturis and on-line pulse-jet bag-filters. KEYWORDS : optimized gas cyclones, recircul

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6