Impact of support on the fabrication of poly (ether-b-amide) composite membrane and economic evaluation for natural gas sweetening

The PVDF MF (polyvinylidenefluoride microfiltration) and PSf UF (polysulfone ultrafiltration) membranes with different pore sizes were used as support to fabricate the PEBA (polyether-b-amide) composite membranes using dip-coating method. The PDMS (polydimethylsiloxane) was coated on top of the PVDF MF support in order to modify the support surface due to the large pore size of this support. Atomic force microscopy (AFM) was used to calculate the surface roughness, the support pore-mouth size and its distribution. The morphology of the prepared membranes was characterized by scanning electron microscope (SEM). The effect of support pore size on the formation of PEBA selective layer and membrane performance was investigated. The results showed that the larger pore size leads to increasing in number of coating times and solution concentration to form the defect-free PEBA selective layer. The application of UF support, because of its smaller pore size, produced membrane with thinner selective layer and higher performance. The effect of membrane performance on the gas processing costs was also studied for the both prepared membranes. The membrane system utilizing the PSf UF based membrane was more economical for producing the sweeten natural gas.