Membrane research subtask, alcohol-fuels program. Annual progress report, FY 1982
A first step toward the evaluation of membranes is to separate ethanol/water mixtures over a range of feed composition, temperature, and pressure. This has been accomplished for an initial set of commercially available membranes using reverse osmosis and pervaporation. Two membrane types (UOP, Inc. RC100 and FilmTec FT30) have performed well. Under reverse osmosis conditions the trends of product fluxes and separation factors are similar for the two types; however, FT30 is somewhat better in both categories. The flux and separation factors decrease rapidly as the wt % ethanol is increased, and water is always selectively permeated. Fluxes remain at an acceptable level over a wide concentration range; however, the separation factor becomes unacceptably low as the effects of osmotic pressure become predominant (15 to 30 wt % ethanol). This report discusses several methods that can overcome the limitations imposed by osmotic pressure. The present results are compared to published work where polyetheramide and particularly polyacrylamide membranes are identified as excellent performers. Pervaporation apparatus was designed, fabricated, installed, and used to test the membrane set. The vacuum system design was conservative to ensure the maintenance of low, down-stream pressures as required for pervaporation. The RC100 and FT30 membranes also performed well during pervaporation. Each membrane was tested over virtually the complete concentration range, and at both ends of the concentration range each membrane passed the least abundant component preferentially. These results contrast to the reverse osmosis results for these membranes where at low ethanol concentrations water is passed preferentially. The difference in behavior under reverse osmosis and pervaporation conditions disagrees with theoretical implications of one presentation using the solution-diffusion model to compare reverse osmosis and pervaporation.
- Research Organization:
- Solar Energy Research Inst., Golden, CO (USA)
- DOE Contract Number:
- AC02-77CH00178
- OSTI ID:
- 6266764
- Report Number(s):
- SERI/PR-255-1776; ON: DE83010324
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ETHANOL
OSMOSIS
SEPARATION PROCESSES
MEMBRANES
PERFORMANCE TESTING
EVAPORATION
POLYMERS
WATER
ALCOHOLS
DIFFUSION
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
TESTING
090222* - Alcohol Fuels- Preparation from Wastes or Biomass- (1976-1989)
140504 - Solar Energy Conversion- Biomass Production & Conversion- (-1989)