Forward osmosis for seawater desalination Membrane development and process engineering

摘要

Although industrial osmotic processes are often referred to as ‘novel’, the possibility for osmotic power generation has been suggested as early as the 1970s. Today forward osmosis is attracting significant interest and this interest has resulted in intensive research. Forward osmosis has been suggested as viable separation process, with numerous potential applications – from osmotic drug delivery and concentration of liquid foods to water purification and re-use in space. Particularly interesting is the possibility of seawater desalination by forward osmosis, as the process is claimed to require little or no pre-treatment of the feed water, due to minor membrane fouling. This alone is a significant advantage over reverse osmosis. udWithin the oil and gas sector, research conducted in the last couple of years shows that low salinity waterflooding can result in enhanced oil recovery, and therefore the industry is searching for new possibilities for off-shore based production of low salinity water. Due to the fact that forward osmosis operates at atmospheric pressure and requires no pressure vessels, the process can be utilized for seawater desalination where low overall equipment weight is required – off-shore oil platforms for example. udThis thesis is focused on the development of membranes for water desalination by forward osmosis, and estimation of the requirements (approximate membrane area and volume) for seawater desalination by a two-stage membrane based forward osmosis – nanofiltration process.