Testing and Optimization of Nano Particles Reinforced PVAm/PVA Blend FSC Membranes for High Pressure Natural Gas Sweetening
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Employing gas separation membranes for natural gas sweetening is a cheaper,simpler, more energy ecient and an environmentally friendly alternative toseparate CO2 from methane. Signicant advances has been made in membranescience and technology over the last couple of decades, and especiallynovel polymer-based FSC membranes have the potential of commercializationin the natural gas treatment industry. In this master's thesis, a selection of nanoparticle reinforced PVAm/PVAblend FSC membranes have been prepared and tested at high pressure fornatural gas sweetening. An ultra-thin selective layer was prepared from commercialpolyvinyl amine (PVAm) and polyvinyl alcohol (PVA) and incorporatedwith either carbon nanotubes or fumed silica, and was cast on thesupport materials polysulfone (PSf), polyvinylidene uoride (PVDF) and cellulose acetate (CA). Permeation tests were carried out at a high pressurepilot scale membrane permeation rig, and the eect of pressure up to 80 barwas investigated. The permeate gas composition was analyzed with a gaschromatograph, and for a total of 11 dierent membranes, the CO2 permeanceand CO2/CH4 selectivity was calculated. Scanning electron microscopywas employed to analyze the morphology of the membranes. Several preparational conditions such as nanoller concentration, solutionltration and selective layer thickness were explored and yielded good results.One membrane in particular showed both high permeance and selectivity athigh pressures, with a CO2/CH4 selectivity of 26.9 and a CO2 permeance of0.034 m3(STP)/m2.h.bar at 60 bar and 30C, with a feed gas ow rate of 0.120 m3/h. The mechanical strength from the nanocomposite PVAm/PVAselective layer with an average thickness 0.670 m on a PSf support showedgood permeability and high selectivity for high pressures.