Spray towers are reactors which can be used for gas treatment. Nowadays, the literature available on mass transfer studies
in spray towers is poor: a few scattered data exist. This work allowed us to follow the evolution of the mass transfer parameters (a and kLa) andH2S removal efficiency in a laboratory-scale spray tower. The influences of both liquid and gas velocities were studied. It could be shown that, for a given liquid velocity, the interfacial area as the volumic mass transfer coefficient increase with an increasing superficial gas velocity, but that the superficial liquid velocity has no or little “apparent” influence on these parameters. This result was partly explained by the non-uniform spray nozzle which leads to increasing wall effects. The experimental values of a and kLa were found to vary, respectively, from 4.3 to 12.5m2 m−3 and from 4.4×10−5 to 1.6×10−4 s−1. Lastly, H2S removal efficiency was quantified. Even if the abatement decreased with UG, it was proved that the quantity ofH2S transferred increased. This result showed that the time left for the H2S mass transfer was not sufficient compared to the quantity of gas, and then the quantity of H2S, sparged in the column. Moreover, the efficiency was found to be higher than 99% when the chlorination rate reached 0.5 gCl2 L−1 whereas it ranged between 62 and 98% for lower chlorination rates. In fact, spraying seems to be an efficient process to remove hydrogen sulphide, but when this operation is implemented in a column, particular attention must be paid to the wall effects.