(200e) Crosslinkable Polyimide Asymmetric Hollow Fiber Membranes for Aggressive Natural Gas Feed Streams
Membranes provide energy efficient and environmentally friendly separations compared to conventional separations (e.g. distillation). Membranes have been widely used in various applications such as natural gas separations, fuel cells and bioseparations. The current challenges of membrane technology are to provide high selective separations with high throughput. Asymmetric hollow fiber membranes provide high throughput by increasing the active surface area to volume ratio and by decreasing the thickness of the actual separating layer. An asymmetric hollow fiber membrane consists of a thin separating layer, called the skin layer, supported on a porous substructure. This substructure provides the mechanical strength of the fiber. A defect free skin layer is required to provide the selective separations and a macrovoid free substructure is required for high pressure separations.
In natural gas purification, it is desired to remove CO2 from methane using highly permselective hollow fiber membranes. At high pressures and in the presence of highly sorbing feed streams, plasticization occurs. This causes the membrane to lose its separation ability, thereby losing the valuable methane product. Suppressing this plasticization can be achieved by a crosslinking post-treatment in the membrane formation process. In this work, a class of crosslinkable polymers is being developed for hollow fiber spinning and characterization with aggressive feed conditions.