Gas permeation test

FIGURE 23.10 Permeated volume versus time for gas permeation test. 

FIGURE 23.11 Schematic of high-pressure gas permeation testing system. 

The transport properties of the membrane were measured by using a membrane permeation unit as described in our previous papers.32 42 Two gas mixtures were used as the feed gas for the gas permeation tests one consisting of 20% C02, 40% H2, and 40% N2, and the other consisting of 1% CO, 17% C02, 45% H2, and 37% N2 (both on dry basis). The second composition was used to simulate the composition of the synthesis gas from autothermal reforming (ATR) of gasoline with air. Argon was used as the sweep gas for the ease of gas chromatography analysis. Unless otherwise stated, the feed pressure was maintained at about 2.0 atm, while the permeate pressure was set at approximately 1.0 atm. 

Fig. 12.11 SEM image of PdAu membrane GTC-31 after several hundred hours of pure and mixed gas permeation testing...

A scanning electron microscope image of the surface of membrane GTC-30 after several hundred hours of pure and mixed gas permeation testing is shown in Fig. 12.16. The EDAX spectrum and tabulated composition data for this membrane is shown in Fig. 12.17. The composition of GTC-30 is 94mass% Pd and 6mass% Cu. 

Volumetric steady-state gas permeation tests at elevated temperatures are typically used to characterize the performance of paUadium membranes. Electrochemical methods are also effective, even at high temperatures [90, 166]. Permeation through palladium depends on a solution-diffusion mechanism, including the steps of chemisorption and dissociation into atoms, absorption into the metal, diffusion through the metal lattice, transfer from the bulk metal to the opposite side, and recombination into molecules for desorption [167, 168]. Difiusion of molecular hydrogen through boundary layers adjacent to the surface is also necessary. 

Vu et al. [122] incorporated CMS materials into polymers to form MMM films for selective gas separations. The CMS, formed by pyrolysis of a PI precursor and exhibiting an intrinsic CO2/CH4 selectivity of 200, was dispersed into a polymer matrix. Pure-gas permeation tests of such MMMs revealed the CO2/CH4 selectivity was enhanced by as much as 40%-45% relative to that of the pure polymer. The effective permeabilities of fast-gas penetrants (e.g., O2 and CO2) through these MMMs are also improved relative to the intrinsic permeabilities of the unmodified polymer matrices. For a CO2/H2 gas mixture, the CO2 will be the fastest permeating component, and H2 will be retained on the feed side to avoid repressurization, in which case the polymer matrix dictates the minimum membrane performance. Properly selected molecular sieves can only improve membrane performance in the absence of defects. The polymer matrix must be chosen so that comparable permeation occurs in the two phases (to avoid starving the sieves) and so the permeating molecules are directed toward (not around) the dispersed sieve particulates. 

Figure 15.11 A schematic diagram for gas permeation test setup.

The measurement of the LEP and the gas permeation test were carried out for the prepared surface-modified PS membranes. The gas permeation test was performed prior to the measnrement of LEP . Figure 6.3 shows a schematic diagram of the testing setup (Qtaishat et al. 2009a). The effective area of the membrane was 9.6 cm. First, the eqnipment was made ready for the gas permeation test by filling the pressure vessel with nitrogen at a pressure of 5 bars. Then, the stainless steel membrane holder inlet valve was opened and the inlet nitrogen pressure was... 

Swelling or sorption test of liquids and vapours through the rubber is obtained by the standard method of ASTM D 814 and ISO 6179 2010 as a general method for various types of rubber. Other standard methods to test liquid and water vapour transmission rate are displayed in Table 27.1. Gas permeation test is obtained by the standard method of ASTM D 1434-82 and ISO 2782 as a general method, especially for oxygen gas mostly using ASTM D 3985 as a protocol for measurement. Table 27.2 exhibits the standard methods of gas permeability test. 

Ferric nitrate may possibly react with carbon matrix releasing CO The release of gas should make the ion-nitrate containing membranes more open and permeable than the membranes without addition of ferric nitrate. In the gas permeation test, single gas permeation was measured at 30°C and 2 bar using the constant pressure system. The order of testing was always N2, H, CH, O2, CO2 and SFg and finally N2 again. 

Table 47 Results of gas permeation tests° of the membranes hydrolyzed for 6, 14 and 74 days...

Before the gas permeation test is carried out, the PAN hollow fiber membranes are potted at both ends to form abimdle consisting of 5-10 fibers. One end of the fiber bundle is sealed into a stainless steel tube of 5/8 in. outer diameter, while the other end is potted in an aluminium cap. Loctite E-30CL epoxy adhesive is used as a potting resin. This bimdle is then inserted in a suitable module as shown in Fig. 5.4. All... 

Gas permeation tests have been carried out for many carbon membranes. However, there is very limited data for the liquid permeation tests, especially for the application of carbon membranes for ultrafiltration (UF) or microfiltration (MF). Some studies [1,2] demonstrated that carbon UF membranes could be made by adding non-carbonizing polymers such as poly(ethylene glycol) (PEG) to the precursor solution. Encouraged by the findings of [3] and [4], Shah and co-woikers successfully made nanoporous carbon UF membranes suitable for bioprocessing applications [5]. 

Some of the experimental results from the single gas permeation test using the membrane fabricated are given in Table 7.1. 

MMM was also fabricated by priming the CMS particles in a small quantity of Ultem 1000 and then the primed particles were dispersed into the Matrimid 5218 solution. The use of Ultem 1000 for the priming polymer and Matrimid 5218 for the polymer matrix was possible since these two polymers are miscible i.e., the DSC measurement gives only a single value of for the mixture of these two polymers. As well, the MMM also exhibits only one T intermediate between those of Ultem 1000 and Matrimid 5218. The performance data of this MMM from the single gas permeation test is shown in Table 8.17. 

SWNT loading 5 wt% of polymer Gas permeation test at 10 psig and 25°C... 

The notations are same as that for Eqn (8.9). The series and parallel model values determine the band in which aU the experimental results for gas permeation tests could be represented. 

The effects of the PEI amount in the casting solution on the permeate flux and on the membrane characteristics were investigated. For each PEI concentration, it was found that the LEP , of the SMM-modified membrane, was higher than that of the unmodified membrane, while the pore sizes were smaller and decreased as the concentration of PEI in the casting solution was increased. The pore sizes of the SMM-modified PEI membranes determined from the gas permeation test were 12-23 nm, lower than the pore sizes of the membranes shown in Table 12.1. However, their DCMD permeabilities were found to be of the same order of magnitude to those of the commercial PTFE membranes (TF200 and... 

Gas Permeation Test Gas permeation test has been used by various groups (Deshmuck and Li, 1998 Wang et al., 1999 Khayet and Matsuura, 2001) to determine both the mean pore size (dp) and the effective porosity (e /Lp), defined as the ratio of... 

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