Tiny membranes could transform how natural gas is processed
Researchers have developed ultra-thin membranes that can remove CO2 and nitrogen from natural gas using a fraction of the equipment currently required. The breakthrough could lower costs for gas producers and help meet pipeline quality standards more efficiently, with potential applications across the $4 trillion global gas infrastructure.
Originaltitel: Natural gas upgrading by high-performance ultra-thin CHA membranes
Ultra-tunna CHA-zeolitiska membran möjliggör effektiv rening av rågas till ledningskvalitet med minimal membranyta. Vid 30 bar tryck och 25 °C uppnår dessa membran en CO2-flux på 1,2 mol/m²·s med selektiviteter på 68–190 för CO2-separation från metan och tunga kolväten. För kvävesortering är 35 °C optimalt, med selektiviteter mellan 5 och 15. En processimulering visar att endast 11,3 m² membranyta krävs för att uppgradera 1000 Nm³/h gas till ledningsstandard. För gasinfrastruktur- och gasbearbetningsföretag är detta relevant eftersom membranseparation kan ersätta energikrävande konventionell uppgradering. Liten membranarea minskar investeringskostnader och platsbehov. Luleå tekniska universitet demonstrerar tekniken, men kommersiell tillgänglighet och skalbarhet återstår att valideras. Företag bör följa utvecklingen för potentiell implementering i mitten av 2020-talet.
<p>Ultra-thin (450 nm) CHA zeolite membranes were assessed for upgrading a synthetic natural gas mixture with a composition representative of the natural gas after a Joule Thomson process. At a feed pressure of 30 bar(a), the membranes provided high fluxes and excellent selectivity for CO2/CxHy, CO2/N2, and N2/CxHy separations. The most favourable conditions for CO2 removal were observed near 25 °C, yielding a CO2 flux of 1.2 (mol/m2·s) and a permeance of 13 × 10−7 (mol/m2·s·Pa) (3900 GPU). At this temperature, selectivities for CO2/CH4, CO2/C2H6, and CO2/C3H8 were 68, 101, and 190, respectively. For N2 separation, the optimal temperature was ∼35 °C, where a N2 flux of 2.5 × 10−3 (mol/m2·s) and a permeance of 1 × 10−7 (mol/m2·s·Pa) (300 GPU) were achieved, along with selectivities of 5 (N2/CH4), 9 (N2/C2H6), and 15 (N2/C3H8). A process simulation based on these separation properties indicated that only 11.3 m2 of membrane area is required to upgrade 1000 Nm3/h of natural gas to pipeline quality at 30 bar(a). These results demonstrate the strong promise of ultra-thin CHA membranes for efficient natural gas upgrading.</p>