In order to understand the asphalt granulation and separation processes in a new technique of solvent deasphalting, this work performs a detailed numerical and experimental study on the hydrodynamics and separation characteristics of low-density particles in a spray granulation tower, the swirl intensity of which can be adjusted by changing the jet direction of four nozzles. The effect of swirl intensity on the fluid behavior and separation performance is investigated. The results show that a jet-driven swirling flow is formed, which depends heavily on the swirl intensity. As swirl increases, the tangential velocity increases and the jet entrainment decreases, which are both beneficial to the tower performance. A multistage variation of separation efficiency is observed in both experiment and simulation. (C) 2011 Elsevier B.V. All rights reserved.