Construction of and experiments with an osmo-power pilot plant. Final report, 1 October 1977-30 September 1978

Technical Report · Tue Feb 20 04:00:00 EST 1979

OSTI ID:5386024

Jellinek, H H.G.; Masuda, H

Various membranes, including homemade asymmetric cellulose acetate membranes were characterized as to their water flux, salt flux, salt rejection and ultimate osmotic pressure reached for 3.5% w/v NaCl solution/fresh water systems. A small osmotic apparatus, equipped with conductance cells and stirrers has been used for obtaining fluxes and salt-rejection data. An Osmonics membrane (asymmetric cellulose acetate membrane) spiral desalination module was built into an osmo-power pilot plant. However, most of the osmotic pressure was lost. It was concluded that desalination membrane arrangements are not suitable for osmo-power production as all are very tightly wound or have very small tube diameters. The theory for osmo-power production on hydrodynamic ground for ideal membranes (i.e., membranes whose only characteristic is semipermeability) and real membranes has been developed. An osmo-power pilot plant has been constructed and successfully operated. It consists of a number of subunits having 26 membranes in parallel (total membrane area 0.16 m/sup 2/). The fresh water/3.5% w/v NaCl saline solution system produced an osmotic pressure of 290 p.s.i. with Osmonics SEPA PS97 membranes (with dye). The water flow rate was 12g ft/sup -2/s/sup -1/, the salt flux 0.79 x 10/sup -8/ mole cm/sup -2/s/sup -1/ and the salt rejection 97%. The power output of the pilot plant amounts (with addition of 5 ppM basic dye) to 1.85 watts/m/sup 2/ of membrane area. It is shown that the higher power-output of the pilot plant is due to concentration polarization of real membranes which produces an effective osmotic pressure for water permeation several times larger than that of the bulk solution. A cost estimate yields 6.5 cents/kWh.

• Research Organization: Clarkson Coll. of Tech., Potsdam, NY (USA). Dept. of Chemistry
• DOE Contract Number: AS05-77ET20335
• OSTI ID: 5386024
• Report Number(s): ORO-5440-2
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140800* -- Solar Energy-- Ocean Energy Systems
ACETATES
CARBOXYLIC ACID SALTS
COST
DIFFUSION
FLOW RATE
FUNCTIONAL MODELS
MEMBRANES
OSMOSIS
PERMEABILITY
PILOT PLANTS
POLARIZATION
RESEARCH PROGRAMS
SALINITY GRADIENT POWER PLANTS