Iranian Journal of Chemical Engineering (IJChE)

Abstract ine"> Chabazite zeolite membranes were synthesized for their potential application in dehydration of natural gas. The membranes were prepared using secondary growth method on porous ·-alumina substrates. Hydrothermal treatment was applied for the synthesis of chabazite seeds. The membranes were synthesized at four temperatures of 100, 120, 140, and 160°C; and duration of 20 h. Separation performance of assynthesized membranes was evaluated through permeation ofwater vapor and methane as single gas. Moreover, the structure and morphology ofas-synthesized chabazite zeolite membranes as well as seeds were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and dynamic light scattering (DLS). The results revealed that the optimum temperature for the synthesis ofchabazite membranes is 140°C while at lower and higher temperatures, lower separation performances were observed. At the optimum synthesis temperature, an ideal selectivity of 23 was obtained for water vapor/methane, while a thin and integrated chabazite zeolite layer of about 5 m in thickness was synthesized over the surface ofalumina substrate.

Abstract Using Co-Mo/MgO catalyst, single walled carbon nanotubes with a diameter of 2nm and a length of 10 μm were produced by chemical vapor deposition process and characterized by XRD, FTIR and SEM. Synthesized single-walled carbon nanotubes were dissolved in water to make a 1w% solution and stabilized by adding sodium dodecyl sulfate surfactant. The synthesized stabilized nanofluid was used in the gaseous hydrate formation at a temperature of 4˚C and pressure of 1000 psig. The results were compared with a water/surfactant control solution and it was found that carbon
nanotubes have reduced the duration of dissolution process by 58.9% and duration of the induction process by 75.5%. In addition, the amount of gas entrapment and stability of the gas in the hydrate were increased by 13.6% and 18.2%,  respectively.