Experimental and theoretical study of a forward osmosis hollow fiber membrane module with a cross-wound configuration

Recent progress indicates that forward osmosis (FO) membranes have promising and versatile potential water- and energy-related applications. In the context of designing and operating a full-scale FO process, this paper experimentally and theoretically analyzed the performance of a large-scale hollow fiber (HF) FO module. We investigated the effects of operating conditions, such as inlet flow rate, membrane orientation, salt concentration, and salt type, on the module performance of a 5-inch-scale HF module with a cross-wound HF configuration. A simple modified analytical model based on the friction-concentration polarization (FCP) model, in which external concentration polarization and pressure drop were considered, was proposed, and the obtained results agreed with the experimental data under all conditions. This analytical study provides beneficial knowledge not only for predicting module performance but also HF module design parameters, such as recovery ratio, operation conditions, and energy consumption, for full-scale FO processes.