Modelling of Temperature Effects on the Performance of Reverse Osmosis Membranes

Mehdizadeh, H.; Dickson, James M.

doi:10.1080/00986449108910865

Cited by 5 publications

(2 citation statements)

References 20 publications

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“…The effects of de-gassing the feed water on the permeate rate for CA membranes (see Figure 6) show a transient increase in permeate flow rate, of 1.5%. However, over the first few months of operation, the permeate output of membranes consistently drop [17,18]. This is usually attributed entirely to compaction, however it could very likely be due in part to cavitation.…”

Section: Discussionmentioning

confidence: 99%

The effects of feed water temperature and dissolved gases on permeate flow rate and permeate conductivity in a pilot scale reverse osmosis desalination unit

Francis

Pashley

2011

Desalination and Water Treatment

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Feed water temperature is an important parameter in determining the optimum conditions for an efficient sea water reverse osmosis (SWRO) process. Increased feed water temperatures are known to increase the permeate flux rate in commercial SWRO systems. There are several factors which link feed water temperature to the operational efficiency of the fundamental membrane desalination process. In this study we have obtained precise data on these effects using two different types of RO membranes in a small scale pilot unit with feeds of sea water, brackish water and pure water. The mechanisms involved have been examined in this work. Pre-heating the feed water to enhance RO efficiency may also lead to greater cavitation within the RO membrane. Cavitation is the formation of cavities in solution upon sudden pressure release, such as across a Reverse Osmosis membrane. These cavities have the potential to hinder permeate flow by blocking sections of the polymer matrix in the skin layer of the membrane. Previously, the effects of de-gassing on the permeate rate in a small scale pilot SWRO system was reported. It was identified that the presence of dissolved atmospheric gases in sea water leads to a potential for cavitation within the porous membranes used in high pressure RO processes. It was also established that the almost complete removal of the initial dissolved atmospheric gases prevented this cavitation. This work has been extended here to include more hydrophobic membranes, which are more likely to produce cavitation. In addition, there is new evidence to support the view that de-gassing the feed water can remove/reduce vapour cavities in the membrane for improved flow, which is maintained even when the feed water is re-gassed. An initial study of a novel method using 2 dissolved Helium as a 'carrier gas' in the feed water, to assist membrane transport, is also reported.

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Section: Discussionmentioning

confidence: 99%

The effects of feed water temperature and dissolved gases on permeate flow rate and permeate conductivity in a pilot scale reverse osmosis desalination unit

Francis

Pashley

2011

Desalination and Water Treatment

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“…During winter seasons, the preheated seawater leaving the heat reject section of the MSF distiller or the nal condenser of the MED plant can be used as feedwater for RO plant. Increase of seawater feed temperature by one degree centigrade will increase the water production of SWRO by approximately 2-3% [47]. The optimal hybrid plant setup will change from case to case because of the large variation in the power demand between summer and winter, with the winter power demand sometimes being only 30% of the summer demand, while water demand remains stable throughout the year.…”

Section: Appendix A22 Membrane Distillationmentioning

confidence: 99%

Primary energy and exergy of desalination technologies in a power-water cogeneration scheme

Altmann¹,

Robert²,

Bouma

et al. 2019

Applied Energy

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The primary energy consumption of a spectrum of desalination systems is assessed using operating information and technical bids for real plants congured with coproduction of electricity. The energy eciency of desalination plants is often rated on a stand-alone basis using metrics such as specic energy consumption, gained output ratio, and second law eciency, which can lead to inconsistent conclusions because the heat and electrical work inputs to the plant have very dierent exergies and costs, which must be taken into account. When both the heat and work inputs are drawn from a common primary energy source, such as the fuel provided to electricity-water coproduction systems, these inputs can be compared and combined if they are traced back to primary energy use. In the present study, we compare 48 dierent congurations of electricity production and desalination on the basis of primary energy use, including cases with pretreatment and hybridized systems, using performance gures from real and quoted desalination systems operating in the GCC region. The results show that, while reverse osmosis is still the most energy ecient desalination technology, the gap between work and thermally driven desalination technologies is reduced when considered on the basis of primary energy. The results also show that pretreatment with nanoltration or hybridization of multiple desalination systems can help to reduce energy requirements. Additionally, the specic type of power plant in the coproduction scheme and its operating parameters can have a signicant impact on the performance of desalination technologies relative to one other.

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Performance of commercial seawater membranes

Wilf

Klinko

1994

Desalination

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Modelling of Temperature Effects on the Performance of Reverse Osmosis Membranes

Cited by 5 publications

References 20 publications

The effects of feed water temperature and dissolved gases on permeate flow rate and permeate conductivity in a pilot scale reverse osmosis desalination unit

The effects of feed water temperature and dissolved gases on permeate flow rate and permeate conductivity in a pilot scale reverse osmosis desalination unit

Primary energy and exergy of desalination technologies in a power-water cogeneration scheme

Performance of commercial seawater membranes

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