The recently developed thermally rearranged (TR) polymeric membranes displayed superior gas separation properties over conventional polymeric membranes, owing to the presence of micro-pores appropriately tuned in cavities size and distribution, thus offering great advantages in gas separation applications, especially in CO2 capture from post-combustion flue gas streams. In this work, the transport properties (flux, permeance and selectivity) of TR polymeric hollow fiber membranes were evaluated with both single gases (CO2, N-2, O-2) and ternary gas mixture (CO2:N-2: O-2=15:80:5) at different temperatures (25, 50, 75 degrees C) and trans-membrane pressure differences (2-5 bar). The results revealed that the CO2 permeance measured under the mixed-gas condition remained the same as the single gas CO2 permeance, while the permeances of other gases decreased, thus leading to a favored increase in selectivity. The effect of water vapor in a ternary gas mixture was studied for the first time, considering that most of the streams of interest contain large amount of water. The presence of water vapor induced a significant permeance decrease for all the three components and a negligible reduction in selectivity. Globally the membranes showed good performance in the whole range of operating conditions investigated. (C) 2015 Elsevier B.V. All rights reserved.