Physical properties measurement and performance analysis of membranes for a multi-stage planar membrane dehumidifier

摘要

Bolto et al. [19] reviewed the vapor permeation through membranes. The permeation process employed a polymeric membrane as a semi-permeable barrier between the feed side under high pressure and the permeate side under low pressure. The materials used in the membrane depended upon the types of compounds being separated, so water transport was favored by hydrophilic material. Scovazzo and Scovazzo [13] indicated hydrophilic polymers such as polydimethylsilozane (PDMS), cellulose acetate (CA), Sulfonated polyethersulfone (SPES), polyethylene oxide (PEO-PBT), sulfonated poly (ether ether ketone) and poly (vinyl alcohol) (EDTMPA), were generally selected for industrial gas dehumidification. Xing et al. [15] developed a novel thin flat sheet zeolite membrane for the air dehumidification application. The membrane used in their work was prepared by deposition of an ultra-thin H2O-selective zeolite membrane film on a thin porous metal sheet support. Bui et al. [16] reported the fabrication of composite membranes from stainless steel wire mesh, porous titania and hydrophilic poly (vinyl alcohol) with varied water vapor permeance and selectivity. The vacuum-based membrane dehumidification was studied systematically by Bui et al. [18] via both theoretical and experimental ana- lyses. A composite membrane was prepared by coating a thin layer of polyvinyl alcohol (PVA)/triethylene glycol (TEG) blend on a flat-sheet thin film composite polymeric substrate.