Abstract
A novel design of an air injection zigzag system was developed to enhance the tubular membrane distillation module's performance for desalination of water, unlike the basic design that works without an air injection system. Designed in a zigzag mode, the membrane distillation module is set to yield a high turbulence flow. Operating parameter effects, for example, the feed temperature (40 degrees C, 50 degrees C, 60 degrees C, and 70 degrees C), feed concentration (1, 3, and 5 g/L), and airflow rate (30-90 L/h), on process performance were investigated. The system proved its capability to enhance the heat and mass transfer coefficients. The basic and developed modules' performances were compared in terms of permeate flux (J(m)) and thermal efficiency (eta). The Reynolds number increased threefold, which consequently, increased the mass transfer coefficient by 25% and the heat transfer coefficient twofold compared to the basic module at airflow rate of 90 L/h. Moreover, the thermal efficiency and permeate flux were higher than the basic module's by roughly 1.4 and 1.5-fold, respectively, for a 5 g/L feed concentration.