Mass transfer in a ‘droplets column’ in presence of solid particles

This work studies the mass transfer efficiency of a new process: the ‘droplets column’. The special feature of this apparatus is the use of high gas throughputs (up to 14 m/s) comparable to smoke from a household waste incinerator. The advantage, as the results show, is the ability to carry out acid gas scrubbing and dust removal simultaneously at a low energy cost. An hydrodynamic study has already been carry out on the droplets column. It begins by measuring pressure drops and liquid hold-ups with three different methods for given operating points. The tendency of the curve remains identical, i.e. a decrease in hold-ups versus liquid flow rate and gas velocity. Considering the errors made on the different methods, the manometric method is more accurate than the other. Therefore, this method can be validated. The study is followed by the liquid residence time determination. All these different results enable to modelize the liquid flow in the column by comparison with well-known models. In this way, the droplets column is assimilated to a sequence of four continuous flow tank reactors. The results concerning hydrodynamic study have been published in N. Muller, B. Benadda, M. Otterbein, Chem. Eng. Tech. 7 (1997) 469–74.