TY - JOUR
T1 - Separation of p-xylene from multicomponent vapor mixtures using tubular MFI zeolite mmbranes
AU - Gu, Xuehong
AU - Dong, Junhang
AU - Nenoff, Tina M.
AU - Ozokwelu, Dickson E.
PY - 2006/9/1
Y1 - 2006/9/1
N2 - MFI zeolite membranes have been synthesized on tubular α-alumina substrates to investigate the separation of p-xylene (PX) from m-xylene (MX) and o-xylene (OX) in binary, ternary, and simulated multicomponent mixtures in wide ranges of feed pressure and operating temperature. The results demonstrate that separation of PX from MX and OX through the MFI membranes relies primarily on shape-selectivity when the xylene sorption level in the zeolite is sufficiently low. For an eight-component mixture containing hydrogen, methane, benzene, toluene, ethylbenzene, PX, MX, and OX, a PX/(MX + OX) selectivity of 7.71 with a PX flux of 6.8 × 10-6 mol/(m2 s) was obtained at 250 °C and atmospheric feed pressure. The addition of a small quantity of nonane to the multicomponent mixture caused drastic decreases in the fluxes of aromatic components and the PX separation factor because of the preferential adsorption of nonane in the zeolite channels. The nanoscale intercrystalline pores also caused serious decline in the PX separation factor. A new method of online membrane modification by carbonization of 1,3,5-triisopropylbenzene in the feed stream was found to be effective for reducing the intercrystalline pores and improving the PX separation.
AB - MFI zeolite membranes have been synthesized on tubular α-alumina substrates to investigate the separation of p-xylene (PX) from m-xylene (MX) and o-xylene (OX) in binary, ternary, and simulated multicomponent mixtures in wide ranges of feed pressure and operating temperature. The results demonstrate that separation of PX from MX and OX through the MFI membranes relies primarily on shape-selectivity when the xylene sorption level in the zeolite is sufficiently low. For an eight-component mixture containing hydrogen, methane, benzene, toluene, ethylbenzene, PX, MX, and OX, a PX/(MX + OX) selectivity of 7.71 with a PX flux of 6.8 × 10-6 mol/(m2 s) was obtained at 250 °C and atmospheric feed pressure. The addition of a small quantity of nonane to the multicomponent mixture caused drastic decreases in the fluxes of aromatic components and the PX separation factor because of the preferential adsorption of nonane in the zeolite channels. The nanoscale intercrystalline pores also caused serious decline in the PX separation factor. A new method of online membrane modification by carbonization of 1,3,5-triisopropylbenzene in the feed stream was found to be effective for reducing the intercrystalline pores and improving the PX separation.
KW - MFI
KW - Membrane modification
KW - Separation
KW - Xylene
KW - Zeolite membrane
UR - http://www.scopus.com/inward/record.url?scp=33745700044&partnerID=8YFLogxK
U2 - 10.1016/j.memsci.2006.02.020
DO - 10.1016/j.memsci.2006.02.020
M3 - 文章
AN - SCOPUS:33745700044
SN - 0376-7388
VL - 280
SP - 624
EP - 633
JO - Journal of Membrane Science
JF - Journal of Membrane Science
IS - 1-2
ER -