Effects of Operational Variables on the Performance of Venturi Scrubbers with Circular Section L. Meili 1 , M. O. Fernandes 1 , C. H. Ataíde 1 , J. J. R. Damasceno 1 1 Federal University of Uberlândia, School of Chemical Engineering - Processes and Development Laboratory, Av. João Naves de Ávila, 2121, Bloco K, CEP: 38408-100, Uberlândia, Minas Gerais, Brazil Keywords: Venturi Scrubber, Performance, Operational Variables. Abstract: Regulations controlling the emissions of pollutants into the atmosphere are becoming stricter. The Venturi scrubbers have a high collection efficiency to remove very small particles from gaseous streams. The main purpose of this work is to determine the overall collection efficiency of Venturi scrubbers with circular section under different operation conditions. The experimental system consisted of a Venturi scrubber with circular section and liquid injection in the throat. A factorial experimental design was carried out; the overall collection efficiency was the response. Three variables were analyzed: the throat length, the air velocity and the liquid flow. Introduction Regulations controlling the emissions of pollutants into the atmosphere are becoming stricter. In order to comply with these constraints, it is necessary to develop new technologies as well as to improve those already existing. The Venturi scrubber is a wet technique that is used for the removal of gaseous pollutants, and can achieve efficiencies of 97% for particles down to 1μm in diameter [3;2]. As a consequence, these devices have been the subject of numerous studies, particularly in recent years. Venturi scrubbers are robust, simple and can be used with acid and corrosive gases, as well as sticky particles [5]. The particulate collection efficiency of a Venturi scrubber is a complex function of many variables including aerodynamic particle size, liquid-to-gas (L/G) ratio, liquid jet penetration, geometrical configuration of the scrubber, particle and gas velocity, and liquid flow. This work studied the performance of Venturi scrubbers with circular section under different operational conditions. Literature Review The Venturi scrubber consists of a duct with circular or rectangular section with three main parts: a convergent section, a cylindrical section or throat and a divergent section or diffuser, as illustrated in Fig. 1. The gas and particles stream enters the convergent section and, as the area decreases, gas velocity increases. Liquid is introduced either at the throat or at the entrance of the convergent section. The gas, forced to move at extremely high velocities in the small throat section, shears the liquid from its walls, producing an enormous number of very tiny droplets. Particle and gas removal occur in the throat section as the exhaust stream