Experiments and Simulation of Transport and Separation of Gas Mixtures in Carbon Molecular Sieve Membranes

Abstract

We report here the results of our recent studies describing the preparation of carbon molecular sieve membranes, their separation and transport characteristics with gas mixtures, and their molecular simulation. Poly(furfuryl alcohol) (PFFA) was used as the polymeric precursor for the preparation of the carbon films. The membranes were tested using single gases H2, CO2, CO, CH4, and Ar, as well as binary mixtures of CO2/CH4 and a four-gas mixture consisting of CO2/CO/H2/CH4. Separation factors for CO2/CH4 in the range of 34−37 were obtained for the binary and the four-gas mixtures. The membrane permeance decreased slowly during continuous testing with the four-gas mixture. This decline in performance was found, however, to be reversible. The initial membrane permeance was recovered by heating the membrane in an inert atmosphere of Ar. Modeling of the membrane's transport characteristics was carried out using a nonequilibrium molecular dynamics simulation. The modeling results agree qualitatively with the experimental data.

First principles-based multiparadigm, multiscale strategy for simulating complex materials processes with applications to amorphous SiC films

“…Hence, one must utilize atomistic modeling and simulation to study the transport processes that take place in the pore space of such materials. We have been fabricating various types of nanoporous materials for use as membranes, such as carbon molecular-sieve membranes, 44 nanotube-polymer composites, 27 and SiC nanoporous membranes. 3 Thus, having established the accuracy of ReaxFF for simulating the pyrolysis of HPCS and the atomistic model of amorphous SiC film, we now turn our attention to the properties of the amorphous SiC film that is produced by the pyrolysis process, after the system is cooled back to room temperature.…”

Effect of carbonization atmosphere on the structure changes of PAN carbon membranes

“…Carbon membranes are novel porous inorganic membranes, which are usually prepared by carbonization of various polymeric materials in vacuum or an inert gas atmosphere. A few studies have shown that the separation performance of carbon membranes is strongly influenced by the choice of precursor materials and carbonization conditions [1][2][3][4][5]. At present, a variety of polymeric precursors, such as polyimide and derivatives [6][7][8][9][10][11], polyacrylonitrile (PAN) [12][13][14], phenol formaldehyde [15][16][17][18][19], polyvinylidene chloride-acrylate terpolymer [20] and poly (furfuryl alcohol) (PFA) [21][22][23][24][25][26], have been used to prepare carbon membranes and demonstrated better separation performance.…”

Structural characterization of polyetherimide‐based carbon molecular sieve membranes

“…In the last few years Ž . several groups, including ours Sedigh et al, 1998Sedigh et al, , 1999 , have studied the transport and separation characteristics of different types of supported or unsupported CMSMs for several Ž gaseous mixtures for a brief review of the results of these . studies see, for example, Sedigh et al, 1999 .…”