Membrane contactor is a technology that intensifies conventional absorption column. However, liquid-to-gas ratios (L/G) of membrane contactor in existing reports are much higher compared to CO₂ absorption column, which results in higher solvent circulation rate and higher consumption in heating energy. This makes the technology less attractive for deep CO₂ removal. Direct reduction of liquid flow rate was not effective in lowering down L/G. Experimental results showed that 50% reduction in liquid flow rate could reduce L/G by 25%, but the reduction in CO₂ flux (33%) was higher due to decrease in liquid phase mass transfer coefficient which was dependent on liquid velocity. An alternative method to reduce L/G through membrane module length increase was proven, where L/G was reduced 70% with only 16% flux reduction. The flux reduction was only observed when L/G dropped below 0.80 L/mol and it was due to depletion of unreacted amine for CO₂ absorption. The lowest L/G value obtained in this study was 36% lower than the conventional absorption column in liquefied natural gas (LNG) process, showing that membrane contactor technology is not only energy-viable and more compact for deep CO₂ removal, but it also offers energy saving advantage.

膜接触器是一种增强传统吸收塔的技术。然而，现有报道中的膜接触器的液气比（L / G）比CO ₂吸收塔高得多，这导致更高的溶剂循环速率和更高的热能消耗。这使得该技术对深层CO ₂去除的吸引力降低。直接降低液体流速对降低L / G无效。实验结果表明，液体流速降低50％可使L / G降低25％，但CO ₂降低由于液相传质系数的降低，通量（33％）较高，而液相传质系数取决于液相速度。通过膜组件长度增加来减少L / G的另一种方法已被证明，其中L / G减少了70％，而通量减少仅16％。仅当L / G降至0.80 L / mol以下时才观察到通量降低，这是由于未反应的胺被CO ₂吸收所消耗。这项研究中获得的最低L / G值比液化天然气（LNG）工艺中的常规吸收塔低36％，这表明膜接触器技术不仅具有能源可行性，而且对于深层CO _2的去除更紧凑，但它的应用还具有节能优势。