An advanced anti-scalant, consisting of a polyacrylate and hydroxyethylidene diphosphonate (HEDP), was tested against the conventional H2SO4 and sodium hexa-meta-phosphate (SHMP) inhibitors in a pilot plant which had parallel RO units. The two units were fitted with identical brackish hollow fine fibre (HFF) permeators arranged in a two-stage mode which received the same brackish feed water, and were operated at the same feed pressure (27.6 bar/400 psig) and product water recovery (70 %). Unit 1 was treated with 9 ppm of as-received advanced anti-scalant, and unit 2 was treated with 6 ppm of SHMP and about 130 ppm of 98 % H2SO4. The pilot plant trial lasted for 3,000 h. The techno-economic evaluation of the two scale control treatments was carried out in terms of pumping energy, the anti-scalants consumed, and the quality and total output of the product water produced in 3,000 h. The pumping energy and scale control treatment costs (as Dollar/m3 of water produced) were same for the two treatments; but in terms of salt rejection, product TDS and output, performance of the advanced anti-scalant was inferior; after 3,000 h the salt rejection of unit 1 (which operated on the advanced anti-scalant) was about 81 % vs. 94 % for unit 2 (H2SO4 + SHMP). Similarly, in 3,000 h unit 1 produced 20 % less water of unacceptable quality (620 ppm) whereas unit 2 produced more water of excellent quality (180 ppm), providing a clear testimony to the superior performance of the conventional H2SO4 + SHMP treatment over the advanced anti-scalant.
Pilot plant evaluation of advances vs. conventional scale inhibitors for RO desalination
Bewertung eines verbesserten Kesselsteinverhütungsmittels im Vergleich zu herkömmlichen Mitteln in einer Pilotanlage einer RO Entsalzung
Desalination ; 103 , 3 ; 189-198
1995
10 Seiten, 3 Bilder, 6 Tabellen, 13 Quellen
Article (Journal)
English
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