A study on pilot-scale degassing by polypropylene (PP) hollow fiber membrane contactors

To meet the stringent requirement on the minimum dissolved oxygen in the production of ultrapure water, we have studied woven fabric membrane contactor in a pilot scale membrane degassing system in a RO production line to replace conventional packed tower for the removal of dissolved oxygen from water. The objective of this work is to study the degassing performance and its mass transfer coefficient of woven fabric membrane contactor under vacuum condition. The experimental results show that compared to membrane contactor packed with fiber bundles, the one packed with woven fabric can achieve higher degassing performance and larger mass transfer coefficient due to its internal structure design resulting in transverse flow other than parallel flow. Effects of the different water flow, different modules, and different operation mode on mass transfer coefficient and degassing performance have been studied. The results show that the well-designed woven fabric membrane contactor as well as the pilot membrane degassing system can effectively remove dissolved oxygen, show low pressure drop and no effect on RO water quality.