1).Thanks Mr.Junfeng for your reply. What seems to be interesting is that this process claims to have achieved huge energy savings say 2.1 to 2.5 kWh/cu.mt against the average Specific power consumption of about 3.5kWh/cu.m ,apart from capex savings due to elimination of some units ,foot print reduction and allied operational expenditure. There are plants working based on this process for almost a decade. The recently commissioned one is in Keppel Singapore. When the entire Desalination fraternity is striving for cost optimisation in terms of energy consumption , why this design is nor prevalent despite this fact? 2). Besides, as may be aware ,membrane pretreatment systems likely to be exposed to pressure surges and hence may be fibre breaks releasing small particles. This would cause fouling/damage RO membranes, if not captured by by CF. 3) CF, apart from being protecting guard for RO membrane, is an indicator to assess the pretretment performance by monitoring the SDI upstream& d/s of CF. 4) Added that, sampling ports to conduct SDI testing are installed u/s & d/s of CF before entering RO If Opted for direct coupling, how the above aspects could be managed?
Published by Yuvaraaj Dhandapany
1).Thanks Mr.Junfeng for your reply. What seems to be interesting is that this process claims to have achieved huge energy savings say 2.1 to 2.5 kWh/cu.mt against the average Specific power consumption of about 3.5kWh/cu.m ,apart from capex savings due to elimination of some units ,foot print reduction and allied operational expenditure. There are plants working based on this process for almost a decade. The recently commissioned one is in Keppel Singapore. When the entire Desalination fraternity is striving for cost optimisation in terms of energy consumption , why this design is nor prevalent despite this fact?
2). Besides, as may be aware ,membrane pretreatment systems likely to be exposed to pressure surges and hence may be fibre breaks releasing small particles. This would cause fouling/damage RO membranes, if not captured by by CF.
3) CF, apart from being protecting guard for RO membrane, is an indicator to assess the pretretment performance by monitoring the SDI upstream& d/s of CF.
4) Added that, sampling ports to conduct SDI testing are installed u/s & d/s of CF before entering RO
If Opted for direct coupling, how the above aspects could be managed?
1 Comment
Hi Yuvaraaj, some of my thoughts.
1. by eliminating the intermediate tank, one reduces the need for repumping to the SWRO. However, from my experience, the reduction in power is not expected to be in the values you have described. I would think it is over-stated. The main bulk of power consumed is still in the SWRO system, and that does not change with a direct UF couping.
2. I have offered some reasons why it is not prevalent in my initial post. The other reason I would think is that for large mega desalination tender, the technical specifications are prescribed. A bidder is not allowed to propose a direct UF coupling if this option is not available in the tender specifications. Unless consultants come on board with the idea, it is often not possible (or very difficult) to propose it from the bidder's point of view.
3. Having a direct coupling does not eliminate the need for quality monitoring d/s of the UF filtered water. Turbidity and SDI measurements are still the standards for determining this.
Without direct coupling, there are still reports and observations of UF fibre breakage and contaminant going down-stream, this does not change. It remains to be seen if direct coupling result in more contaminants going downstream - but in my opinion, it certainty demands higher mechanical strength on the UF fibre due to the fluctuating pressures.
Published by Junfeng Kok, Principal Process Engineer at Hyflux