Oxygen Separation Using Magnetic Membranes

In spite of its established role in reliably providing high-throughput, high-purity oxygen for gasification, cryogenic distillation-based air separation is costly and energy-intensive to operate. The process accounts for up to 15% of the total gasification plant capital cost, and consumes a major portion of in-plant power use. Other oxygen supply technologies, such as pressure swing adsorption and polymeric membranes, are available but cannot provide oxygen at a high enough purity (>95%) for gasification or are only commercially viable on a small scale.
Since the first cryogenic oxygen production patent issued to Carl Von Linde in 1903, the technology has been refined through engineering configuration and optimized for greatest economic efficiency. However, given the current limitations for further improvements in the efficiency of cryogenic air separation plants the development of technology that would significantly lower its costs is unlikely. Based on the current state of technology, there is great incentive to develop new approaches for oxygen separation.

This invention describes the application of mechanical membranes for the separation of oxygen from air at ambient temperatures. The membranes are composed of multiple pores having magnetic regions that augment a magnetic field on one side of the pore structure while reducing the magnetic field on the opposite side of the pore. The technology enables the large-scale exploitation of the differences in magnetic susceptibilities between a paramagnetic component such as oxygen which is attracted toward the magnetic pore field and diamagnetic components such as nitrogen, which are repelled. This method is anticipated to overcome the limitations of current separation methods allowing for energy efficient separation of highly purified oxygen.