Separation of organic azeotropic mixtures by pervaporation
Distillation is a commonly used separation technique in the petroleum refining and chemical processing industries. However, there are a number of potential separations involving azetropic and close-boiling organic mixtures that cannot be separated efficiently by distillation. Pervaporation is a membrane-based process that uses selective permeation through membranes to separate liquid mixtures. Because the separation process is not affected by the relative volatility of the mixture components being separated, pervaporation can be used to separate azetropes and close-boiling mixtures. Our results showed that pervaporation membranes can be used to separate azeotropic mixtures efficiently, a result that is not achievable with simple distillation. The membranes were 5--10 times more permeable to one of the components of the mixture, concentrating it in the permeate stream. For example, the membrane was 10 times more permeable to ethanol than methyl ethyl ketone, producing 60% ethanol permeate from an azeotropic mixture of ethanol and methyl ethyl ketone containing 18% ethanol. For the ethyl acetate/water mixture, the membranes showed a very high selectivity to water (> 300) and the permeate was 50--100 times enriched in water relative to the feed. The membranes had permeate fluxes on the order of 0.1--1 kg/m{sup 2}{center dot}h in the operating range of 55--70{degrees}C. Higher fluxes were obtained by increasing the operating temperature.
- Research Organization:
- Membrane Technology and Research, Inc., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG03-89ER14067
- OSTI ID:
- 5926894
- Report Number(s):
- DOE/ER/14067-T2; ON: DE92005585
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
COPOLYMERS
PERMEABILITY
ORGANIC COMPOUNDS
SEPARATION PROCESSES
POLYAMIDES
AZEOTROPE
ENERGY CONSERVATION
MEMBRANES
PROGRESS REPORT
DOCUMENT TYPES
ORGANIC POLYMERS
POLYMERS
400105* - Separation Procedures
320303 - Energy Conservation
Consumption
& Utilization- Industrial & Agricultural Processes- Equipment & Processes