Abstract
The performance of a tapered bubble column that generates higher fractional gas hold up with least power consumption than existing systems under similar hydrodynamic conditions is reported in this article for particulate‐laden‐SO~2~ scrubbing. Firstly, quiescent batch studies were carried out to analyze SO~2~ removal at various initial particle concentrations. Results revealed that presence of particles improved the SO~2~ removal efficiency to about 14–27% that was elucidated by the facilitated adsorptive mass transport. The performance of the system was analyzed in subsequent experimentation operating it under continuous mode for particulate‐laden‐SO~2~ scrubbing using water and dilute NaOH. Results indicated that the removal efficiency of SO~2~ was improved to about 25%/(W/m^3^) due to change in the column geometry and to about 16.7%/(W/m^3^) due to presence of particles (fly‐ash) within the range of variables studied. The enhancement of removal of SO~2~ due to presence of particulate matter and that due to alkali scrubbing were quantified and compared. Operating regimes of maximum removal efficiencies (∼100%) of SO~2~ and particulates either alone or in combination were determined from experimental results. Empirical and semi‐empirical correlations were developed for predicting the scrubbing performances of the tapered column in water and dilute NaOH, respectively. Experimental values fitted excellently well with the predicted values. The superiority of the tapered bubble column over a conventional bubble column for scrubbing of particulates and SO~2~ either alone or in combination was described. © 2008 American Institute of Chemical Engineers Environ Prog, 2009