(587c) Development of New Siloxane Terpolymers for Enhanced C3+ Hydrocarbon Recovery from Natural Gas | AIChE

(587c) Development of New Siloxane Terpolymers for Enhanced C3+ Hydrocarbon Recovery from Natural Gas

Authors 

Yang, J. - Presenter, Aramco Services Company
Harrigan, D. J., Aramco Services Company: Aramco Research Center
Vaidya, M., Saudi Aramco
Duval, S., Saudi Aramco
Hamad, F., Saudi Aramco
Natural gas plays a significant role in the global energy mix. Although raw natural gas consists primarily of CH4, it can contain significant amounts of other gas components, including acid gases (CO2 & H2S), N2, He, and C3+ hydrocarbons. These C3+ hydrocarbons are valuable chemical feedstocks and can be used as a liquid fuel for power generation and seawater desalination. Commercially available rubbery siloxane membranes are utilized in industry for the rejection of N2 and for the concentration of C3+ hydrocarbons in the membrane permeate stream. However, current state-of-the-art PDMS membranes with (Me2SiO)n backbones show lower C3+/CH4 selectivities under industrially relevant feed streams and testing conditions. In this work, modified crosslinked siloxane terpolymer (VinylMeSiO)p(Me2SiO)m(OctMeSiO)n membranes (Ter-PDMS) were fabricated and evaluated for separations of C3+ hydrocarbons from natural gas. Results show that modified crosslinked siloxane Ter-PDMS membranes showed enhanced C3+ separation performance compared to conventional PDMS membrane under simulated typical field gas testing conditions (i.e. feed pressures up to 850 psi for multicomponent gas mixture consisting C1-C5 hydrocarbons, CO2, N2, and BTEX). At 800 psi, Ter-PDMS membranes exhibited C4/CH4 mixed gas selectivity and C4H10 permeability of 17.2 and 15100 Barrers, respectively. These results emphasize the observations that membrane separation performance is strongly related to the testing conditions and feed compositions, highlighting the importance of exploring and designing better modified rubbery siloxane membrane materials for the actual industrial process.