Hollow fiber membrane contactor for hydrogen sulfide odor control

Abstract

AbstractHollow fiber membrane modules are extensively used as gas–liquid contactors for acid gas removal from waste gas streams. Hydrogen sulfide is an important indoor and outdoor contaminant, but, given its toxicity, a limited number of experimental results have been reported for this compound. Moreover, chemical absorption has been exclusively investigated. In this study, hydrogen sulfide odor control by absorption in water thanks to a hollow fiber contactor has been studied both experimentally and theoretically. The scrubbing of hydrogen sulfide from air gas mixture is investigated in two porous polypropylene (PP) hollow fiber modules of different contact area and fiber packing fraction. The gas phase is circulated in the lumen of the fiber bore and the liquid phase in the shell in a nonwetted mode, i.e. the membrane pores being filled with gas. The gas phase was run in countercurrent contact with the liquid phase at constant pressure. A laminar parabolic velocity has been employed to describe the convective diffusive mass transport equation which has been solved analytically and numerically. The calculated extents of hydrogen sulfide depletion reasonably compare with the generated experimental results for both membrane modules. Up to 85% of acid gas could be removed at gaseous flowrates of 200 cm3/min for the large module and removals as high as 89% at 10 cm3/min have been observed for the smaller one. The overall mass transfer coefficients calculated from the experimental data, agree satisfactorily with those generated by the mathematical model. The relation of the dimensionless Sherwood number to the Graetz number is in a good agreement with the Levêque semianalytical solution. © 2007 American Institute of Chemical Engineers AIChE J, 54: 122–131, 2008