The present research investigates and optimizes the aerodynamic performance of a newly designed compact size three stage mobile gas-solid separator. This separator is designed to collect solid particles with different characteristics at a minimum pressure drop. The minimum particle diameter to be completely collected is 1 mu m at solid loading 20 g/m(3). The first stage of the separator is a settling chamber which is designed to collect coarse particles (particles down to particle diameter 100 mu m). The second stage is a cyclone separator where medium to fine particles (particles down to particle diameter 15 mu m) are to be collected. Particles escaping the cyclone separator are collected in the third stage which is a bag filter. A separator conceptual aerodynamic design is first performed to obtain overall separator dimensions. CFD simulation is used in order to optimize the separator aerodynamic performance and reduce the separator size. The separator is then constructed and experimentally investigated. Comparison between CFD results at design point and measured separator total pressure drop shows good agreement. (C) 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.