The possible application of membranes for CO2 separation in the treatment of non-valuable streams (e.g.,
flue gasofapowerplantorcementindustry)orvaluablestreams(e.g.,biogas)hasbeenanalyzed.Some
selection criteriausefulinthechoiceofmembranegasseparationforCO2 capturearediscussedto
evaluatetheadvantagespotentiallyofferedbymembranesystems.Membraneselectivityrangingfrom
30–50 (valuesofcommercialmembranes)to100–500(valuesofmostpromisinglaboratorymembranes)
and differentfeed/permeatepressureratioswereconsideredforthevariouscases.Thecompositionand
recoveryofcarbondioxideinthemembrane-treatedstreamwerethetargetparameterstakeninto
account asguidelinesintheevaluationoftheseparationtechnologyperformance.General “maps” of CO2
permeate concentrationversusCO2 recoveryhavebeendevelopedbymeansofasimpletoolthattakes
into accounttheinfluence ofthemostimportantparametersaffectingthemembranesystem
performance (thatis,membraneselectivityandpermeationdrivingforce).Theanalysesindicatedthat
the separationdependsonvariousinterrelatedfactors:themembranematerial(selectivityand flux), the
operating conditions(pressureratio),andthe final requirements(CO2 recoveryandcomposition).Also,
the operationallimitandthepotentialitiesofthemembranegasseparationtechnologywereanalyzed
under theseconditions.The “maps” proposed andutilizedforCO2 separation arevalidandcanbe
utilized forothergasseparationsinwhichthemembraneshowsselectivitiessimilartothosetakeninto
account here.