Fluid flow and mass transfer in an industrial-scale hollow fiber membrane contactor scaled up with small elements

Abstract

Current gas/liquid membrane contactors are classified into tubular hollow fiber contactors and tube-shell cross flow hollow fiber contactors. They are usually built with a closed and integrated structure, which reduces the maintainability of the contactor and makes the scaling-up of the contactor inconvenient. In this paper, a novel gas/liquid hollow fiber membrane contactor is proposed. It is consisted of many changeable and standard small contactors (elements), in which the fibers are randomly packed. These randomly packed small elements are then serially and orderly arranged to form the scaled up contactor for industrial applications. A two-dimensional predictive model is proposed to study the performance of the contactor, which is validated by air humidification experiments. The effects of inter-elements and intra-element flow maldistributions are investigated. Correlations are proposed to estimate the performance of the contactor from the parameters of the elements. It is found that for the contactors built with elements of high packing densities (0.5), the inter-elements effect is dominant for flow maldistribution, but for contactors built with elements of low packing densities (0.35), the collaborative effect of inter-elements and intra-element is dominant. It could maximally decrease the average air side Sherwood numbers by about 83%, with a pressure drop reduction of about 50%. The scaled up contactor has a comparable performance to the small elements when the elements are optimized, which shows the good scalability of this novel contactor.