(70c) CO2-Selective Membranes Composed of Cross-Linked Polyethers | AIChE

(70c) CO2-Selective Membranes Composed of Cross-Linked Polyethers


Barillas, K. - Presenter, National Energy Technology Laboratory, University of Pittsburgh
Enick, R. M. - Presenter, University of Pittsburgh
Luebke, D. - Presenter, US DOE/NETL
Morreale, B. D. - Presenter, U.S. Department of Energy, National Energy Technology Laboratory

Membranes could be an integral part of the post-combustion capture of CO2 from the effluent gas stream of coal-fired power plants.  The objective of this work is to design polymeric membranes that have very high CO2 permeability and high selectivity toward CO2 (i.e. very low H2 and N2 permeability).  It is our hypothesis that the favorable thermodynamic interactions that enable certain polymers to dissolve in dense CO2 at extremely high pressure will also allow membranes composed of these polymers to exhibit high CO2 permeability and CO2 selectivity at low pressure.  (These polymeric membranes have recently been assessed for the pre-combustion capture of CO2 from a CO2- and H2-rich shifted gasifier stream).

The crosslinked polymeric membranes used in this study of post-combustion capture of CO2 from a N2-rich stream have been previously assessed and shown promise for the pre-combustion separation of CO2 from a H2-rich shifted fuel gas stream. Candidates include either (a) CO2-philic polymers with linear repeat units such as poly(ethylene glycol) (PEG), polytrimethylene ether glycol (i.e. linear polypropyleneglycol), and polytetramethylene glycol ether (i.e. linear polybutylene glycol), or (b) CO2-philic polymers with branched repeat units such as polypropyleneglycol and polybutylene glycol.  Results of mixed gas permeability and selectivity values for CO2/N2 gas pairs will be discussed, and the performance of membranes with linear and branched repeat units will be contrasted.