Study On The Fabrication Technology Of Multilayer Hollow Fiber Gas Separation Membranes

Membrane separation technology has been transformed from the lab-scale to industrialization.Due to the very superior performance and advantages of the membrane technology,it has been rapid developed in the 21st century.Hollow fiber gas separation membrane has played a unique role in different fields,because of the advantages of low energy consumption,small footprint,low investment,and easy installation.Their applications include petroleum,metallurgy,machinery,aerospace,and food preservation,such as separating oxygen from air,recovering hydrogen from synthetic ammonia tail gas,separating hydrogen and carbon monoxide from petroleum cracked mixed gas,and collecting carbon dioxide from flue gas.This research aims to produce a hollow fiber gas separation composite membrane that can be industrialized.Therefore,the focus has been paid to high gas flux with moderated selectivity.First,we selected polyacrylonitrile(PAN)to make hollow fiber substrate by the dry-wet spinning method.Then the surface of the membrane was coated with silicone rubber or Pebax as the selective layer.The effects of the concentration,viscosity,organic solvent,and storage time of the coating solution(silicone rubber,Pebax)on the performance of the composite membranes were analyzed based on SEM,water contact angle,DMA and gas separation performance tests.Moreover,the effect of the CRA additive to inter-layer adherent was studied.The PAN/PDMS hollow fiber composite membrane had a CO2 flux of 3000 GPU,while the CO2/N2 selectivity of the PAN/PDMS/Pebax composite membrane reached 29.The multi-filament coating of hollow fiber membrane was also studied.We designed and built a device that could coat 50 m membrane at one time.The hollow fiber's gas separation property was the same as the one made by small-scale coating technology.