*Polymer-Based Membranes for C3+ Hydrocarbon Removal from Natural Gas DOI: http://dx.doi.org/10.5772/intechopen.103903*

Results show that Pebax® 1074 and 1657 containing low of polyether segment (50– 60 wt%) retained the highest CO2/CH4 selectivity (*α* = 16–19) but lower C3+/CH4 selectivities (C3H8/CH4 = 4.7–5.2; C4H10/CH4 = 11–12). Surprisingly Pebax® 2533 containing higher polyether segment (80 wt%) exhibited higher C3H8/CH4 selectivity of 6.7 and C4H10/CH4 selectivity of 17.6), which are greater than the C3H8/ CH4 selectivity of 5.3 and C4H10/CH4 selectivity of 10.5 for commercially available PDMS membrane under the same testing conditions (800 psi, 25°C) [25]. However, Pebax® 2533 membrane shows 93% and 91% decrease in C3H8 and C4H10 permeabilities, respectively, compared with that of PDMS.
