Membrane Contactors and Catalytic Membrane Reactors in Process Intensification

Abstract

Membrane operations, with their intrinsic characteristics of efficiency and operational simplicity, high selectivity and permeability for the transport of specific components, compatibility between different membrane operations in integrated systems, low energetic requirement, good stability under operating conditions, environment-compatibility, easy control and scale-up, and large operational flexibility, represent an interesting answer for the rationalisation of chemical productions. Many membrane operations are practically based on the same hardware (materials), only differing in their software (methods). The traditional membrane separation operations (reverse osmosis, micro-, ultra-and nanofiltration, electrodialysis, pervaporation etc.), already largely utilised in many different areas, are today completed with new membrane systems such as catalytic membrane reactors and membrane contactors. At present, the possibility to redesign important industrial production cycles by combining various membrane operations available in the separation and conversion units, so realising highly integrated membrane processes, is an attractive opportunity because of the synergic effects that can be reached. Additionally, the design of the integrated membrane production cycle in principle satisfy, the requirements for an advanced process intensification strategy.Membrane crystallizers, membrane emulsifiers, membrane strippers and scrubbers, membrane distillation, membrane extractors, etc., can be realized and integrated in the production line together with other existing membrane operations for advanced molecular separation and chemical transformations, overcoming existing limits of the more traditional membrane processes.

Increasing the Performance of Vacuum Membrane Distillation Using Micro-Structured Hydrophobic Aluminum Hollow Fiber Membranes

“…Membrane separation processes are an emerging technology that feature low energy consumption, especially membrane contactors with porous membranes [4,5]. Therefore, there have been many studies of membrane distillation (MD) processes in the last two decades [6][7][8].…”

“…For membranes with various geometries, hollow fiber membranes have been widely studied because of their potential for low mass transfer resistance and high packing density [4,5,20]. Whether organic polymer or inorganic, ceramic hollow fiber membranes are generally fabricated using phase inversion, which is also a common way to produce the membrane for MD [3].…”

Valorization of artichoke wastewaters by integrated membrane process

“…Both VMD and OD are included within the so-called 147 "membrane contactors family". According to Drioli et al (2006), membrane contactors 148 do not offer any selectivity for a particular species with respect to another but simply act 149 as a barrier between the phases involved. The species are transferred from one phase to 150 the other by only diffusion.…”

Membrane engineering for process intensification: a perspective

“…MD has been investigated for various applications, such as seawater desalination, fruit-juice concentration, VOC removal from aqueous streams, separation of liquid mixtures and treatment of physiological solutions. 7 Microporous membranes also allow gas/liquid membrane contactor (GLMC) operations, promoting an efficient mass transfer through a high interfacial area. Packing material for conventional absorption columns offers a specific surface area in the range of 100-1000 m 2 m −3 ; the surface/volume ratio in membrane hollow fibres is one order of magnitude higher.…”

“…As single units, membrane contactors might also be more efficient than corresponding traditional unit operations, but their combination is expected to generate important synergistic effects and to improve the efficiency of the overall process. 7 Extractive fermentation carried out by membrane contactor technology (such as glucose fermentation to ethanol, with housed yeast cells immobilized on wooden chips and dibutyl phthalate used as an extractant) 8 is a typical case in which the use of membranes avoids energy-intensive and complex technologies. PV is one of the best-developed membrane technologies, having great potential for the intensification of various industrial processes, such as breaking azeotropes 9 and removing volatile organic compounds (VOCs) from liquids.…”