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Table of Contents:

Summary

Depending on the pore size of the carbon membrane, different transport mechanisms may dominate membrane separation processes. Carbon membranes with a selective surface flow mechanism may be applied to separation of heavy hydrocarbons, whereas carbon molecular sieve membranes are particularly useful for the separation of small gas molecules that are alike in size such as H2-C02, C02-CH4, olefin-paraffin, organic solvents etc. (see details in Part 2: Carbon Membrane Applications).

Nomenclature

Symbol Explanation Unit/value

Latin characters

c concentration mol m3

D diffusion coefficient m2 S-1

E activation energy kj mol-1

Symbol Explanation Unit/value

h Planck constant 6.626 x 10~34 J s

/ flux mol nr2 s-1

к Boltzmann constant 1.381 x 10"23 J K"1

/ Membrane thickness m

M Molecular weight g mol4

N Knudsen number

P permeability Barrer (1 Barrer = 0.33 x

10~15 mol m nr2 s_1 Pa-1)

p pressure Bar, or mbar

q flow rate m3 fr1

R molar gas constant 8.314 J K_1mol_1

rp pore radius m

S entropy; solubility J Кmol m-3 bar1

T temperature К

v gas velocity m s'1

x mole composition

у mole composition

Greek characters

Д delta (finite difference) -

П permeation number

Ф pressure ratio

a selectivity

0 stage-cut

X mean free path m

Subscripts

A activation

d diffusion

F feed side

H, L high, low pressure

side

i, j component z, j

К Knudson

P permeate side

p preexponential

  • s sorption
  • 0 usually presents

pre-exponential

References

[1] W.J. Koros, H. Ma, T. Shimidzu, Terminology for membranes and membrane processes (IUPAC Recommendation 1996), J Membr Sci, 120 (1996) 149-159.

[2] M.-B. Hagg, J.A. Lie, A. Lindbrathen, carbon molecular sieve membranes. A promising alternative for selected industrial applications,. A promising alternative for selected industrial applications, Ann NY Acad Sci, 984 (2003) 329-345.

[3] M.B. Rao, S. Sircar, Performance and pore characterization of nanoporous carbon membranes for gas separation, / Membr Sci, 110 (1996) 109-118.

[4] J. Gilron, A. Soffer, Knudsen diffusion in microporous carbon membranes with molecular sieving character, J Membr Sci, 209 (2002) 339-352.

[5] C.J. Geankoplis, Transport Processes and Unit Operations, 3rd ed., Prentice-Hall, Englewood Cliffs, NJ, 1993.

[6] S. Glasstone, K.J. Laidler, H. Eyring, The Theori/ of Rate Processes, 1st ed., McGraw- Hill Book Co., New York, 1941.

[7] C. Nguyen, D.D. Do, К. Haraya, K. Wang, The structural characterization of carbon molecular sieve membrane (CMSM) via gas adsorption, j Membr Sci, 220 (2003) 177-182.

[8] R.W. Baker, Membrane Technology and Applications, 2nd ed., Wiley, Chichester, 2004.

[9] D.R. Paul, J.P. Jampol'skij, Polymeric Gas Separation Membranes, CRC Press, Boca Raton, FL, 1994.

[10] R. Baker, Membrane Technology and Applications, 2nd ed., McGraw-Hill, 2004.

[11 ] M. Mulder, Basic Principles of Membrane Technology, Kluwer Academic Publishers, Dordrecht, the Netherlands, pp. 496-498.

[12] L. Lei, A. Lindbrathen, M. Hillestad, M. Sandru, E.P. Favvas, X. He, Screening cellulose spinning parameters for fabrication of novel carbon hollow fiber membranes for gas separation, Ind Eng Client Res, 58 (2019) 13330-13339.

Part 2

 
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