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Membranes used for membrane distillation (MD) inhibit passage of liquid water while allowing permeability for free water molecules and thus, for water vapour. [1] These membranes are made of hydrophobic synthetic material (e.g. PTFE, PVDF or PP) and offer pores with a standard diameter between 0.1 and 0.5 μm (3.9 × 10 −6 and 1.97 × 10 −5 ...
Dense membranes are utilized for gas separations (removal of CO 2 from natural gas, separating N 2 from air, organic vapor removal from air or a nitrogen stream) and sometimes in membrane distillation. The later process helps in the separation of azeotropic compositions reducing the costs of distillation processes. Ranges of membrane based ...
Membrane distillation is a type of distillation in which vapors of a mixture to be separated are passed through a membrane, which selectively permeates one component of mixture. Vapor pressure difference is the driving force. It has potential applications in seawater desalination and in removal of organic and inorganic components.
Multi-stage flash distillation (MSF) is a water desalination process that distills sea water by flashing a portion of the water into steam in multiple stages of what are essentially countercurrent heat exchangers. Current MSF facilities may have as many as 30 stages.
The Claude "Bud" Lewis Carlsbad Desalination Plant is a desalination plant in Carlsbad, California. [2] [3] The San Diego County Water Authority (SDCWA), the recipient of the fresh water produced by the plant, calls it "the nation’s largest, most technologically advanced and energy-efficient seawater desalination plant."
Single-phase desalination processes include reverse osmosis and membrane distillation, where membranes filter water from contaminants. [15] [17] As of 2014 reverse osmosis (RO) made up about 52% of indirect methods. [21] [22] Pumps push salt water through RO modules at high pressure. [15] [21] RO systems depend on pressure differences. A ...
Whereas the common PEM fuel cell, also called Low Temperature Proton Exchange Membrane fuel cell (LT-PEM), must usually be operated with hydrogen with high purity of more than 99.9 % the HT-PEM fuel cell is less sensitive to impurities and thus is typically operated with reformate gas with hydrogen concentration of about 50 to 75 %.
Even distillation does not completely purify water, because of contaminants with similar boiling points and droplets of unvapourised liquid carried with the steam. However, 99.9% pure water can be obtained by distillation. Direct contact membrane distillation (DCMD) passes heated seawater along the surface of a hydrophobic polymer membrane ...