dc.description.abstract | Employing gas separation membranes for natural gas sweetening is a cheaper,
simpler, more energy ecient and an environmentally friendly alternative to
separate CO2 from methane. Signicant advances has been made in membrane
science and technology over the last couple of decades, and especially
novel polymer-based FSC membranes have the potential of commercialization
in the natural gas treatment industry.
In this master's thesis, a selection of nanoparticle reinforced PVAm/PVA
blend FSC membranes have been prepared and tested at high pressure for
natural gas sweetening. An ultra-thin selective layer was prepared from commercial
polyvinyl amine (PVAm) and polyvinyl alcohol (PVA) and incorporated
with either carbon nanotubes or fumed silica, and was cast on the
support materials polysulfone (PSf), polyvinylidene
uoride (PVDF) and cellulose acetate (CA). Permeation tests were carried out at a high pressure
pilot scale membrane permeation rig, and the eect of pressure up to 80 bar
was investigated. The permeate gas composition was analyzed with a gas
chromatograph, and for a total of 11 dierent membranes, the CO2 permeance
and CO2/CH4 selectivity was calculated. Scanning electron microscopy
was employed to analyze the morphology of the membranes.
Several preparational conditions such as nanoller concentration, solution
ltration and selective layer thickness were explored and yielded good results.
One membrane in particular showed both high permeance and selectivity at
high pressures, with a CO2/CH4 selectivity of 26.9 and a CO2 permeance of
0.034 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/PVA
selective layer with an average thickness 0.670 m on a PSf support showed
good permeability and high selectivity for high pressures. | |