High recovery reverse osmosis using a recycle loop

✍ Scribed by Cal C. Herrmann

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 820 KB
• Volume: 91
• Category: Article
• ISSN: 0011-9164
• DOI: 10.1016/0011-9164(93)80065-u

✦ Synopsis

A single-pump configuration with feedback has been found useful in reaching high brine osmotic pressures in continuous-flow operation. Enhanced brine concentration, and enhanced product/feed water recovery fraction, can be obtained by recycle of a second-stage permeate of intermediate quality.

For spaceflight recycling of hygiene water this permits lower pressurevessel ratings, or higher water recovery, or both. With feed of 1,000 ppM concentration, recoveries of 95-97% are achieved at a pressure of 1.65 MPa. With feed of seawater concentration, recoveries of 50% to 70% have been achieved using a single pump at 5.5 MPa.

Membrane performance parameters have been obtained for high water recovery operation in the pressure range up to 1.4 MPascals (200 psig) for system modeling. Simple equations can be fitted to these measurements, from which RO system performance can be predicted, or simulated as part of a model of system performance.