Asymptotic analysis of performance of membrane modules for gas separations

Conference · Sun Jan 01 00:00:00 EST 1989

OSTI ID:5730826

Basaran, O A; Harris, M T

The nonlinear equations that govern the variation of molar flow rates and mole fractions in membrane modules for separating binary gas mixtures are solved analytically by asymptotic analysis in {alpha}, the selectivity of the fast gas with respect to the slow gas. The results are explicit analytical expressions that show the effect of process parameters and idealized flow patterns (cross-flow, CF, co-current-flow, CO, and counter-current-flow, CC) on system performance. When the selectivity is low, a regular perturbation analysis shows that the CC module is the most efficient, followed by CF and CO modules, except when p{sub r}, the permeate to feed pressure ratio, is zero in which case the performance of all three is the same. When the selectivity is large, the nature of the problem changes whether the mole fraction of the fast gas on the feed side at the entrance to the module, {chi}{sub in}, is less than or greater than p{sub r}. When {chi}{sub in} > p{sub r}, a singular perturbation analysis of the equations shows that performance is independent of the type of idealized flow pattern in the module. However, when {chi}{sub in} {le} p{sub r}, a regular perturbation analysis shows that the CC module is the most efficient, followed by CF and CO modules. The results presented enable one to gain a quantitative understanding of membrane-based separations without resorting to extensive numerical calculations. 13 refs., 5 figs.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5730826
• Report Number(s): CONF-891013-1; ON: DE90000699
• Resource Relation: Conference: 6. symposium on separation science and technology for energy applications, Knoxville, TN (USA), 22-27 Oct 1989
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
GASES
SEPARATION PROCESSES
MEMBRANES
PERFORMANCE
ASYMPTOTIC SOLUTIONS
FLOW RATE
MIXTURES
PERMEABILITY
DISPERSIONS
FLUIDS
400105* - Separation Procedures
990230 - Mathematics & Mathematical Models- (1987-1989)