Membranes for Flue Gas Treatment: Transport behavior of water and gas in hydrophilic polymer membranes

Fossil fuel fired power plants produce electricity and in addition to that large volume flows of flue gas, which mainly contain N2, O2, and CO2, but also large quantities of water vapor. To prevent condensation of the water vapor present in this flue gas stream, water needs to be removed before emission to the atmosphere. Commercial dehydration processes such as the use of a condenser or a desiccant system have several disadvantages and membrane technology is an attractive, energy efficient alternative for dehydration of gas streams. The work presented in this thesis focuses on the characterization of the molecular gas and water vapor transport properties of two different types of polymeric membranes. The fundamental understanding of water vapor and gas transport phenomena through these materials is particularly interesting since both materials are different in their chemistry and physical state: - PEBAX® is a block copolymer which shows molecular transport through the soft polyethylene oxide based rubbery phase. - S-PEEK (sulfonated poly ether ether ketone) shows molecular transport through an amorphous glassy phase with ionic groups present which will preferentially be hydrated over the apolar matrix. The two polymeric systems vary strongly in relation to polymer/vapor interactions, relaxation phenomena, and separation performance of the membranes.