Permeation studies, with hollow-fiber modules

The experimental procedure for permeation studies with hollow fiber modules was Identical to that described by Bhave and Slrkar (12) for flat Celgard films except that the flat film test cell was replaced by the hollow fiber module (see Figure 1 in reference (12)). 

Immobilized Liquid Membranes. A pilot plant study of the recovery of ethylene and propylene from a polypropylene reactor off-gas stream was presented by Hughes et al. (23). Aqueous solutions of Ag Ion were Immobilized In the pore structure of commercial reverse osmosis hollow fiber modules. The pilot plant operated at feed pressures of 414-827 kPa, feed flow rates of 1.42-4.25 m /h at STP, and sweep flow rates of 3.79 10" - 0.114 m /h hexane. Permeate streams with propylene concentrations In excess of 98 mole % were observed in pilot plant operation with modules containing 22.3 to 37.2 m membrane area. 

The membrane model in the implemented ACM module was first validated with the experimental results of Pan (1986). In the experiments, the effect of varying stage cut (that is, the fraction of feed that permeates through the membrane) on mole fraction of H2 in the permeate was studied using asymmetric hollow fiber membranes in co- and counter-current configurations. Parameters of the membrane module can be found in Table lO.A.l stage cut varies from 0.34 to 0.55 in the counter-current configuration and from 0.35 to 0.6 in the... 

The developed membrane model/ACM module was also validated against the results of Davis (2002). In his study, a mathematical model of a hollow-fiber membrane was developed in Aspen HYSYS for air separation. Parameters used in the simulation of this separation are given in Table 10.A.2. As can be seen in Table 10.A.3, the ACM model predictions are very close to the simulation results of Davis (2002), with a maximum difference of 0.41% in permeate O2 concentration. 

Microporous polypropylene hollow fibers with an ultra-thin plasma-polymerized silicone skin on the outer surface, in both pilot-plant and laboratory studies, allow a VOC removal higher than 95% [33]. Composite membranes with a POMS separation layer, in flat and spiral wound modules, effectively remove toluene vapor from air by applying vacuum at the permeate side [34]. 

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