This paper describes the design and testing of a trommel screen system for the separation of undersized particulates. The trommel screen system consisted of a cylindrical separation device that rotated to perform size separation. A series of experiments were carried out at room temperature to demonstrate the screening efficiency of this method under different operating conditions. The dynamic model and velocity analysis of undersized particulates in the trommel body are also discussed. The experimental results show that the screening efficiency could be enhanced by using a mass flow rate of 360 cm/s, a dust concentration of 10,000 ppmw, an inclination angle of the trommel body of 50 and a rotational speed of the trommel body of 43 rpm. Moreover, the results also indicate that this type of method could be useful for dust particulate separation in a moving granular bed filter system. The main focus of the current study is the development of a trommel screen system for a moving granular bed filter that could be applied in a high-temperature environment. (C) 2010 Elsevier B.V. All rights reserved.