Use of transverse flow hollow fibers for bubbleless membrane aeration

Abstract

A novel sealed-end transverse flow hollow fiber membrane module was evaluated for aeration of water. In this process the sealed-end fibers were held vertically from the bottom of a channel. Pure oxygen under high pressure was maintained in the fiber. The water to be aerated was pumped over the outside of the fibers. Due to the concentration gradient, oxygen transferred through the air-filled pores and dissolved directly into the water without forming bubbles. Since the primary orientation of the fiber is perpendicular to the liquid flow, a high mass transfer coefficient was achieved at low liquid velocities compared to parallel flow modules. Measured mass transfer coefficients for hollow fibers held at different angles are presented in this paper. In addition, the design equations for transverse-flow aerators are developed. The mass transfer behavior of a small scale transverse-flow bubblesless hollow fiber membrane module was measured experimentally and the results were compared with the theoretical predictions.