Oxygen separation membrane based on facilitated transport using cobalt tetraphenylporphyrin-coated hollow fiber composites

• Oxygen in flue gas causes degradation of absorbent in carbon capture process.
• Oxygen facilitated transport hollow fiber membrane is proposed for oxygen removal.
• Membrane is characterized by microscopy and spectroscopy and gas permeation.
• Coating layer is a thin dense layer with an increasing packing density.
• Oxygen/carbon dioxide selectivity is reversed by current membrane.

The post-combustion flue gas discharged from coal-fired power plants is a major source of carbon dioxide, which contributes to global warming. Oxygen in post-combustion flue gas causes oxidative degradation of the amine-based solvents used in the carbon capture process. In this study, a cobalt tetraphenylporphyrin mediated facilitated transport membrane is considered for flue gas pretreatment. It is possible to exactly characterize the membrane by various microscopic and spectroscopic techniques. The results show that the hollow fiber is evenly coated as a thin dense layer with an increasing packing density. Gas permeation test shows that the oxygen/nitrogen and oxygen/carbon dioxide selectivity values reach 2.8 and 1.5, respectively, with an oxygen permeance of 53 GPU at 0.05 bar. It is expected that, because of the oxygen facilitated transport behavior, the membrane system will be able to remove oxygen from post-combustion flue gas using the current membrane for flue gas pretreatment, retarding the degradation of the absorbent.

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