Experimental and modeling study on fouling of hollow-fiber membranes by fine dust aerosol particles

This work aimed to study the pressure drop evolution of hollow-fiber membranes (HFMs) during aerosol loading. We tested two types of polypropylene HFMs varying in inner fiber diameter with an ASHRAE A2 test dust. Data was recorded including pressure drop, flowrate/permeate velocity and accumulated mass of particles until reaching the final pressure drop. The results showed a slow pressure drop increase even when loaded with extremely high (units of g/m(3)) dust concentrations. The membranes were easily cleanable simply by shaking, with a minimal residual pressure drop. The particle loading profile (pressure drop/dust load curve) was dependent on the inner diameter of hollow fibers and permeate velocity. The loading profile of a new HFM was independent of dust concentration. However, when a regenerated membrane was used, the dependence on the dust concentration was obvious. The same was true for the fouling rate, which was higher for the regenerated membrane. Theoretical and empirical models for dust cake pressure drop were in a strong disagreement with experiment data. In practical applications, they will be rather limited to a very specific low volume, or short-term high volume filtrations due to the higher pressure drops caused by the hollow-fiber geometry.