Design and Built Up of Vacuum Membrane Distillation (VMD) Unit

MSc Project By: Gigin Johan Oommen (2186887)

Supervisor: Dr. Xue Jin

Introduction Water covers 72% of the earth's surface, making it the most abundant substance on our planet earth, yet most of this resource is inaccessible or unfit for drinking. The water available for human use is declining rapidly due to global industrialization and gradual rising of environmental pollution. In the hindsight, it is essential to develop water treatment technology which is both sustainable and economical. Membrane distillation (MD) fits perfectly into this category. Objective The objective of this project is to design and build a Vacuum Membrane Distillation (VMD) unit. Membrane Distillation (MD) MD can be defined as a thermal driven separation process where only water vapour can pass through pores of the hydrophobic membranes. It can effectively remove volatile organic compounds from feed solution. Vacuum Membrane Distillation (VMD) The principle of VMD is to apply a low pressure on the permeate side of a hydrophobic micro porous membrane whereas the feed water is heated on the other side of the membrane. Water is vaporized at pore inlet and then diffuses through the membrane. Finally, it is condensed outside the membrane module. The driving force of the process is the trans-membrane difference between the water vapor partial pressure at the membrane wall on the feed side and the vapor partial pressure on the permeate side.

Fig 1: Principle of VMD technique [1], [2]

Fig 2: Schematic diagram of VMD unit.

Fig 3: Experimental rig of VMD unit. Fig 4 Fig 5 Fig 6 Fig 7 Table 1: Membrane characteristics Fig 8 [3] Conclusion Ø There is an increase in distillate flux with increase in feed temperature and flow rate. Ø The distillate flow rate increases with increase in permeate side vacuum pressure. Ø VMD can effectively remove non-volatile and organic matters. Ø MD is energy efficient, economical and sustainable if coupled with renewable sources of energy such as solar power.

References [1] M. A. E.-R. Abu-Zeid, Y. Zhang, H. Dong, L. Zhang, H.-L. Chen, and L. Hou, “A comprehensive review of vacuum membrane distillation technique,” Desalination, vol. 356, pp. 1–14, 2015. [2] J.-P. Mericq, S. Laborie, and C. Cabassud, “Vacuum membrane distillation for an integrated seawater desalination process,” Desalin. Water Treat., vol. 9, no. 1–3, pp. 287–296, 2009. [3] “About Hollow Fiber Membranes - Koch Membrane Systems.” [Online]. Available: http://www.kochmembrane.com/Learning-Center/Configurations/What-are-Hollow-Fiber-Membranes.aspx. [Accessed: 14-Aug-2015]

University of Glasgow, charity number SC004401

MSc Mechanical Engineering