Control biofouling through membrane flux balance by interstage boosting
Haytham Abdelfatah
Fluid Equipment Development Co. – FEDCO, Monroe, MI 48162, USA
https://doi.org/10.5004/po2024120
ABSTRACT
The main problem in increasing recovery systems is membrane flux as you need to increase the pressure to get product from last element but in reality, all this extra pressure provided to the 1st element which increase the flux and recovery for this element because this element works on feed water and does not need all this pressure. At the same time the rear elements work with high TDS water (high osmotic pressure) but with lower pressure compared with front elements. Seawater desalination membrane manufacturing design guidelines indeed recommended element recovery of around 8% and an element flux lower than 24 LMH (L/m2/h). These guidelines are designed to optimize the performance and longevity of the desalination membranes. Regarding biofouling, which is a significant challenge in membrane processes, research has shown a tight relationship between element concentration polarization and biofouling. Element polarization can exacerbate biofouling by creating conditions that favor the growth of biofilms on the membrane surface. This, in turn, can lead to a phenomenon known as biofilm-enhanced concentration polarization (BECP), which can degrade water quality and reduce membrane lifetime. To mitigate biofouling, it is recommended to keep the element polarization below 13%. This helps in maintaining the quality of the permeates and the efficiency of the membrane process. By controlling element polarization, it is possible to reduce the risk of biofouling and extend the operational life of the desalination membranes. In paper we will compare the single stage design, each element boost pressure, 3-stage design and 2-stage design to see the best technical result and balance between technical result and capital cost so we can get the optimum design.
Keywords: Driven pressure; Flux balance; Interstage boost; 2 stages; Biofouling and membrane lifetime
