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

#### **Figure 8.**

*Aging-induced permeance drop of penetrants in polyimide (6FDA-BPDA-DDBT) membrane aged for 18 months [49].*

#### **Figure 9.**

*Comparison of (a) C4H10 permeance and (b) C4H10/CH4 selectivity of POMS/AC MMMs in multi-component gas mixture (2 vol% C4H10) and C4H10-CH4 binary mixtures (1, 2 or 5 vol% C4H10) at 20°C [57].*

under simulated typical field gas streams. Results shows that C4H10 vol% had significant influence on membrane separation performances due to the C4H10 induced swelling of PDMS based rubbery siloxane membranes. Similarly, Mushardt et al*.* [57] reported the permeation properties of poly(octylmethylsiloxane) (POMS)/ active carbon (AC) mixed matrix membranes (MMMs) under binary and multicomponent gas mixtures (**Figure 9**). The best separation performance was achieved under multicomponent gas mixture at highest average fugacity of C4H10 caused by increasing feed pressure and high concentration of C4H10 in feed gas mixture. These outcomes carry the message that membrane separation performance is strongly related to feed gas compositions and testing conditions. Thus, to fully exploit the use of membranes for actual C3+ hydrocarbons separation and removal, not only higherflux and cost-effective new membranes are needed, but also it is worthy to pay more attention to the influence of gas compositions and testing conditions.
