Applications of Helical Versus Straight Hollow Fiber Membranes: A Review
Engineering and Technology Journal
A comprehensive comparison was performed between helical and straight hollow fibers. Applications of helical hollow fibers membrane were studied. The use of helical fibers minimizes fouling and concentration polarization. Helical configuration promotes turbulence. The production of straight and helical hollow fibers plays an important role in developing hollow fiber membrane technology that encompasses a broad range of designs. During the last two decades, scientific studies devoted to
... aight hollow fibers were more abundant than those focused on helical fibers. Several major applications considering side-by-side testing of these two geometries are discussed in this review. For membrane extraction, desalination, and membrane contactor processes, it is observed that permeability rates are 10%-400 % higher for helical fibers compared to straight fibers. This outcome is justified by the presence of Dean-vortices-induced flow turbulences inherent to the geometry of helical membranes. These conditions give rise to an uptake of mass and heat transfer coefficients and a reduction of temperature and concentration polarization phenomena. Aside from enhanced flow properties, helical hollow fiber bundles tend to be more robust by design, thus exhibiting better resiliency over long service operations than straight bundles. One persistent shortcoming of the helical fibers seems to be an increase in pressure drop. However, this does not always translate into a higher energy consumptioni.e., versus straight bundles. Given the performance advantage, product robustness, and adaptiveness to a broad range of applications, the adoption of helical hollow fiber technology deserves growing support from the membrane community in academic and industrial settings.