membrane distillation

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membrane distillation

[′mem‚brān ‚dis·tə′lā·shən]
(chemical engineering)
A separation method that uses a nonwetting, microporous membrane, with a liquid feed phase on one side and a condensing permeate phase on the other. Also known as membrane evaporation; thermopervaporation; transmembrane distillation.

Membrane distillation

A separation method in which a nonwetting, microporous membrane is used with a liquid feed phase on one side of the membrane and a condensing, permeate phase on the other side. Separation by membrane distillation is based on the relative volatility of various components in the feed solution. The driving force for transport is the partial pressure difference across the membrane. Separation occurs when vapor from components of higher volatility passes through the membrane pores by a convective or diffusive mechanism. See Convection (heat)

Membrane distillation shares some characteristics with another membrane-based separation known as pervaporation, but there also are some vital differences. Both methods involve direct contact of the membrane with a liquid feed and evaporation of the permeating components. However, while membrane distillation uses porous membranes, pervaporation uses nonporous membranes.

Membrane distillation systems can be classified broadly into two categories: direct-contact distillation and gas-gap distillation. These terms refer to the permeate or condensing side of the membrane; in both cases the feed is in direct contact with the membrane. In direct-contact membrane distillation, both sides of the membrane contact a liquid phase; the liquid on the permeate side is used as the condensing medium for the vapors leaving the hot feed solution. In gas-gap membrane distillation, the condensed permeate is not in direct contact with the membrane.

Potential advantages of membrane distillation over traditional evaporation processes include operation at ambient pressures and lower temperatures as well as ease of process scale-up. See Membrane separations

References in periodicals archive ?
This is the first paper in which VMD system is discussed in a series of our publications on the CFD simulation based on finite element analysis for membrane distillation [17, 18].
Unfortunately the current membrane distillation method is too expensive for use in countries and municipalities that need potable water," said Mitra.
For modelling water vapor transfer through membranes in various systems, which are mostly working under atmospheric pressure conditions, except vacuum membrane distillation systems, the term [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] in equation (2), expressing the resistance due to air inside the membrane pores, is significant.
According to the methods for creating low pressure at permeate side, various MD process including directcontact membrane distillation (DCMD) (3), air-gap membrane distillation (AGMD) (4), sweeping-gas membrane distillation (SGMD) (5), and vacuum membrane distillation (VMD) (6) are considered.
The paper on membrane distillation as a new technique for treating produced water from oil industry has been accepted for publication in the international journal 'Desalination' and will be appearing on Jan.
Keppel's membrane distillation technology for seawater desalination - 2010
Greenbelt Resources was selected to participate via public bid process for its three years of experience with membrane distillation technology as well as for the reputation of Diversified technology innovator Floyd Butterfield.
Other research include brine treatment technologies like eutectic freeze crystallisation, membrane distillation, and heavy metal recovery coupled with hydrogen production from acid mine drainage via microbial electrolysis.
The objective of this research project is to optimize the technology of membrane distillation for the treatment of reverse osmosis brines.
Kshitij Nilkanth, programme manager, environmental technologies practice, Frost & Sullivan, tells Utilities Middle East: "In recent years, the market has seen a slew of new concepts, including forward osmosis, membrane distillation, tri-hybrid applications using nano-filtration and low temperature distillation.
Membrane Distillation (MD) process has various applications, such as desalination, wastewater treatment and in the food industry.
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