Low-temperature flashing basis of Westinghouse process
Flash evaporator
Water vapor
Power out
Fresh water by-product
Turbine generator
Water Surface vapor * condenser
η
Warm Out water in
ΓΤ
.Air (ncïf\cïCi
*
• Compressor " ( power
Cold Out water in
EVANS
GLYCOL DIMERCAPTOACETATE HS—(CH2C02CH2)2—SH
gle-stage turbine. The hull for the plant serves to provide necessary buoyancy and is simultaneously a pressure vessel for the plant. According to the Westinghouse developers, the reason that opencycle processes have not been more vigorously pursued is the difficulty in designing an acceptable turbine. Ex tremely low operating pressures re quire very large or multiple turbines, which have been prohibitively ex pensive. However, a breakthrough in turbine design was achieved by adapting lightweight, glass-fiber, honeycomb materials originally de veloped for helicopter rotors. The turbine for the conceptual in stallation proposed would be about 100 feet in diameter, with blades 40 feet long. Rotary speed would be 200 rpm and the total turbine efficiency would be more than 80%. One problem that does present
major difficulties is purging the high-volume system of noncondensable gases. This would have to be done with axial compressors, consti tuting a significant power drain. In summing up the progress made so far, the Westinghouse developers note that although the technology necessary for commercial develop ment is far from fully developed, it requires no breakthroughs for landbased prototypes. For a seagoing prototype, there are still uncertainties related to operations afloat. However, some very general, preliminary cost estimates have been made for the state of Hawaii, which is considered most suitable for OTEC plants. The integrated average costs of power generation over the expected 30-year life span of comparable OTEC and oil-fired power plants are 3.53 cents per kwh and 5.33 cents per kwh, re spectively. D
I I HC CH
II II
+
HS(CH 2 C0 2 CH 2 ) 2 SH
HC CH
Ι
Ι
Ψ
I
I
HC—S—(CH 2 C0 2 CH 2 ) 2 —S—CH HC I
CH I
HC—C—CI CI—C—CH+HS(CH 2 C0 2 CH 2 ) 2 SH 0 X 0 I II • II I HC—C—S—(CH 2 C0 2 CH 2 ) 2 —S—C—CH I I
η X — C — X + n HS—M—SH X X X X I • | | —S—M—S—C —S—M—S—C—S—M—S—C I I I X X X
Vibration precipitates fibers from polymer solutions L Brian Keller, a researcher at Hughes Aircraft Co., Culver City, Calif., inspects polymer fibers produced by a vibrating coil suspended in solution. In the pro cess of developing this technique, Keller and his colleagues have produced what is believed to be the first "self-rein forcing" fibrous composite. Although the technique grew out of efforts to increase the strength of encapsulating resin for high-voltage electronic devices, whose tiny interstices tend to block entry of conventional reinforcing fibers, com pany spokesmen say it holds wide promise for the production of filters, high-strength composites, medical im plants, and reinforced elastomers. The in-situ fiber networks are formed when isotactic polymer solutions are vibrated at sonic frequencies in the 20- to 20,000-Hz range, while slowly being cooled. The individual fibers can be as thin as several hundred angstroms. Those fibers long enough to test have
Cross-Linking agent and specialty monomer by addition across unsaturation — by reaction with aldehyde, ketone and acid chloride groups.
Samples available on request.
tensile strengths of about 100,000 psi, versus about 400 psi for the bulk poly mer. The self-reinforcing composite was created by first precipitating a polypro pylene network from a solution of liquid styrene, then curing the solvent to solid polystyrene.
EVANS
cHemencs
Organic Chemicals Division, W* ft. Grace & Co. 90 Tokeneke Road, Darien, CT. 06820 Cable: EVANSCHEM/TWX 710-457-3356
Sept. 3, 1979 C&EN
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