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Membrane Water Treatment Volume 3, Number 4, October 2012, pages 253-266 DOI: https://doi.org/10.12989/mwt.2012.3.4.253 |
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Hybrid salts precipitation-nanofiltration pretreatment of MSF and RO seawater desalination feed |
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Aiman Eid Al-Rawajfeh
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| Abstract | ||
| In this work, the effect of hybrid salts precipitation-nanofiltration (SP-NF) process on the scale deposits in thermal and membrane desalination processes has been studied. The analysis was carried out to study the scale formation from the Arabian Gulf seawater in MSF and RO reference processes by changing the percentage of pretreatment from 0 to 100%. Four different SP-NF configurations were suggested. A targeted Top Brine Temperature (TBT) of 130oC may be achieved if 30% portion is pretreated by SP and/or NF processes. As a rule of thumb, each 1% pretreatment portion increases the reference TBT of 115oC by 0.6oC. For both MSF and RO, parallel pretreatment of certain percentage of the feed by SP and the rest by NF, showed the lowest scale values. The case showed the best values for sulfate scale prevention and the highest values of increasing the monovalent ions relative to the divalent scale forming ions. Sulfate scale is significant in MSF process while carbonate scale is significant in RO. Salt precipitation was suggested because it is less costly than nanofiltration, but nanofiltration was used here because it is efficient in sulfate ions removal. | ||
| Key Words | ||
| pretreatment; desalination; salt precipitation; nanofiltration; scale deposition | ||
| Address | ||
| Aiman Eid Al-Rawajfeh : Tafila Technical University (TTU), Department of Chemical Engineering, P.O. Box 179, 66110 Tafila, Jordan Jordan Atomic Energy Commission (JAEC), Shafa Badran, Amman, Jordan | ||