Permeation data gases

TPX has a high selectivity for hydrogen gas permeation. Data of selected polymers are shown in Table 4.5. 

As a general rule, membrane material changes affect the diffusion coefficient of a permeant much more than the sorption coefficient. For example, Figure 2.18 shows some typical gas permeation data taken from a paper of Tanaka et al. [23], The diffusion and sorption coefficients of four gases in a family of 18 related polyimides are plotted against each other. Both sorption and diffusion coefficients... 

Figure 7.8 C3H6/C3Hg experimental upper bound based on pure gas permeation data over the range 1-4 atm feed pressure.

Equations 19.33 and 19.34 can be employed over a range of pressure using gas permeation data obtained in a different reference pressure. 

Typical single gas permeation data for relatively thick MFI membranes are given in Fig. 9.23 [71]. At 673 K all the gases show a linear dependence on the (feed) pressure (Henry behaviour) as is the case at 300 K for the noble gases and for CH4, whereas butane and ethane exhibit saturation at low and higher... 

Fig. 9.30. Separation and permeation behaviour of a mixture of 0.31 kPa paraxylene ( ) and 0.26 kPa o-xylene (A) as a function of temperature. Single gas permeation data are also given 0.62 kPa px (A) and 0.52 kPa ox (V). The total pressure was 100 kPa, the balance being He. After Vroon et al.

Comparison with the Gas Permeation Data Since both t 3 and I3 represent quantities related to free space in polymers, they should be correlated with the gas permeation characteristics. We have been systematically comparing PALS data and... 

For thin-film composite MIP membranes, according to gas permeation data defect ( pinhole ) free, a higher performance than for the thick free-standing films from similar polymers was observed (seeTable 1) fluxes of up to 18 nmol/cm h at real... 

Membrane-based gas separations have attracted intense interest because of their far less energy consumptive and continuous simple process. MOFs, as newly developed porous materials, are attractive in manbrane separation however, there are only a few reports that include gas permeation data available to date. 

In Fig. 8.57, Ultem 1000 showed 2-5 °C increase from the pure Ultem 1000 by the loading of CMS. In contrast all Matrimid 5218 loaded membranes show an increase in of ca. 15 °C. What caused this difference is currently not clear. Table 8.16 summarizes the pure gas permeation data of the mixed matrix membranes. 

The data for MMM is intermediate between the two component polymers. Effect of CMS is found in the enhanced selectivity. Mixed permeation was examined at the pressures up to 900 psia and with a gas mixture 10% COJ90% CH, using a Ultem 1000-CMS MMM (35 vol% CMS). The data are summarized in Fig. 8.60. Pure gas permeation data are also included in Fig. 8.60. Both CO2 permeability and COj/CH permselectivity are greater for MMM than for pure Ultem 1000. Both decrease gradually as the feed pressure is increased. 

The gas permeation data of the PEK series of polymers are summarized in Table I, and those for the PES series are recorded in Table II. 

Farhangi S, Shariaty-Niassar M, Soltanieh M. A new resistance model for the interpretation of gas permeation data of composite and asymmetric membrane. J Chem Pet Eng 2012 46(2) 73-86. 

Pure gas permeation data of membranes prepared using these additives were obtained from a constant pressure permeation system for CO2, CH4, O2 and N2. In order to know the effect of the structure of the nonsolvents, nonlinear regression analysis was attempted. Each additive was split into structural components groups. Several linear polynomial first and second order equations as well as nonlinear polynomial equations were attempted to derive an empirical correlation between the number of structural components and gas permeation data. A second order polynomial equation was derived to predict the pure CO2/CH4 permeance ratio from the structural components of the nonsolvents. From the structural studies the authors concluded that nonsolvent additives that possess a long straight hydrocarbon chain such as 2-ethyl-l-hexanol, 1-octanol and 2-decanol showed the highest pure gas permeance ratio. 

Table 23. Single gas permeation data of SPPOBr (20% brominated with an I. E. C. value of 1.8 meq./g of dry polymer) coated TFC hollow fiber membrane modules (small modules)...

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