Application of constant volume – variable pressure (time-lag) method to measure oxygen gas diffusion through polypropylene pipes

2016 ◽  
Vol 55 ◽  
pp. 287-296 ◽  
Author(s):  
Suleyman Deveci ◽  
Yalcin Oksuz ◽  
Tamer Birtane ◽  
Mualla Oner
Keyword(s):  
Time Lag ◽  
Gas Diffusion ◽  
Constant Volume ◽  
Variable Pressure ◽  
Pressure Time ◽  
Oxygen Gas

scholarly journals Highly Permeable Matrimid®/PIM-EA(H2)-TB Blend Membrane for Gas Separation

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 46 ◽  
Author(s):  
Elisa Esposito ◽  
Irene Mazzei ◽  
Marcello Monteleone ◽  
Alessio Fuoco ◽  
Mariolino Carta ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
Gas Transport ◽  
Gas Permeability ◽  
Time Lag ◽  
Gas Diffusion ◽  
Gas Permeation ◽  
Spectrometric Analysis ◽  
Competitive Sorption ◽  
Transport Parameters ◽  
Mixed Gas

The effect on the gas transport properties of Matrimid®5218 of blending with the polymer of intrinsic microporosity PIM-EA(H2)-TB was studied by pure and mixed gas permeation measurements. Membranes of the two neat polymers and their 50/50 wt % blend were prepared by solution casting from a dilute solution in dichloromethane. The pure gas permeability and diffusion coefficients of H2, He, O2, N2, CO2 and CH4 were determined by the time lag method in a traditional fixed volume gas permeation setup. Mixed gas permeability measurements with a 35/65 vol % CO2/CH4 mixture and a 15/85 vol % CO2/N2 mixture were performed on a novel variable volume setup with on-line mass spectrometric analysis of the permeate composition, with the unique feature that it is also able to determine the mixed gas diffusion coefficients. It was found that the permeability of Matrimid increased approximately 20-fold with the addition of 50 wt % PIM-EA(H2)-TB. Mixed gas permeation measurements showed a slightly stronger pressure dependence for selectivity of separation of the CO2/CH4 mixture as compared to the CO2/N2 mixture, particularly for both the blended membrane and the pure PIM. The mixed gas selectivity was slightly higher than for pure gases, and although N2 and CH4 diffusion coefficients strongly increase in the presence of CO2, their solubility is dramatically reduced as a result of competitive sorption. A full analysis is provided of the difference between the pure and mixed gas transport parameters of PIM-EA(H2)-TB, Matrimid®5218 and their 50:50 wt % blend, including unique mixed gas diffusion coefficients.

scholarly journals Modeling of oxygen gas diffusion and consumption during the oxic transient in a disposal cell of radioactive waste

2014 ◽  
Vol 41 ◽  
pp. 115-127 ◽  
Author(s):  
Laurent De Windt ◽  
François Marsal ◽  
Jérôme Corvisier ◽  
Delphine Pellegrini
Keyword(s):  
Radioactive Waste ◽  
Gas Diffusion ◽  
Oxygen Gas

Studies into design and operation of microbial fuel cells using oxygen gas diffusion electrodes

2017 ◽  
Vol 91 ◽  
pp. 222-227
Author(s):  
A.-L. Schneider ◽  
H. Schell ◽  
S. Hild ◽  
K.-M. Mangold ◽  
A. Tiehm
Keyword(s):  
Fuel Cells ◽  
Microbial Fuel Cells ◽  
Gas Diffusion ◽  
Gas Diffusion Electrodes ◽  
Oxygen Gas

Modeling Oxygen Gas Diffusion Electrodes for Various Technical Applications

2019 ◽  
Vol 91 (6) ◽  
pp. 720-733 ◽  
Author(s):  
Fabian Kubannek ◽  
Thomas Turek ◽  
Ulrike Krewer
Keyword(s):  
Gas Diffusion ◽  
Gas Diffusion Electrodes ◽  
Oxygen Gas

scholarly journals Effect of Bridgehead Methyl Substituents on the Gas Permeability of Tröger’s-Base Derived Polymers of Intrinsic Microporosity

Membranes ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 62 ◽  
Author(s):  
Richard Malpass-Evans ◽  
Ian Rose ◽  
Alessio Fuoco ◽  
Paola Bernardo ◽  
Gabriele Clarizia ◽  
...  
Keyword(s):  
Gas Permeability ◽  
Time Lag ◽  
Composite Membranes ◽  
Detailed Comparison ◽  
Gas Diffusion ◽  
Size Selectivity ◽  
Surface Areas ◽  
Troger's Base ◽  
Polymers Of Intrinsic Microporosity ◽  
Intrinsic Microporosity

A detailed comparison of the gas permeability of four Polymers of Intrinsic Microporosity containing Tröger’s base (TB-PIMs) is reported. In particular, we present the results of a systematic study of the differences between four related polymers, highlighting the importance of the role of methyl groups positioned at the bridgehead of ethanoanthracene (EA) and triptycene (Trip) components. The PIMs show BET surface areas between 845–1028 m2 g−1 and complete solubility in chloroform, which allowed for the casting of robust films that provided excellent permselectivities for O2/N2, CO2/N2, CO2/CH4 and H2/CH4 gas pairs so that some data surpass the 2008 Robeson upper bounds. Their interesting gas transport properties were mostly ascribed to a combination of high permeability and very strong size-selectivity of the polymers. Time lag measurements and determination of the gas diffusion coefficient of all polymers revealed that physical ageing strongly increased the size-selectivity, making them suitable for the preparation of thin film composite membranes.

Determination of Sorption Rate and Apparent Solid-Side Diffusivity of Pure H2O in Silica Gel Using a Constant Volume/Variable Pressure Apparatus

1991 ◽  
Vol 113 (4) ◽  
pp. 257-263 ◽  
Author(s):  
L. T. Lu ◽  
D. Charoensupaya ◽  
Z. Lavan
Keyword(s):  
Mass Transfer ◽  
Water Vapor ◽  
Moisture Content ◽  
Silica Gel ◽  
Time Variation ◽  
Constant Volume ◽  
Variable Pressure ◽  
Test Unit ◽  
Sorption Rate ◽  
Sorption Data

Silica gel-water vapor is commonly suggested as a working media for solar-powered desiccant cooling systems since the system can be regenerated at relatively low temperatures. In the present study the sorption rates of water vapor by regular density silica gel particles were measured in the pressure range of 1–25 torr using a constant volume/variable pressure apparatus. The sorption rate was determined from recorded time variation of water vapor pressure in a test unit of known volume during the sorption process. The mass transfer film resistance was eliminated by evacuating the system and by introducing pure water vapor into the test unit. The apparent solid-side diffusivity was obtained by matching the analytical solution of the simultaneous heat and mass transfer governing equations to the experimental data. The uptake measurements had been performed for three particle sizes of silica gel (150 μm, 1 mm, and 3 mm). The tests were performed sequentially in small steps over a range of initial silica gel moisture content ranging from near zero up to 0.25 kg H2O per kg dry silica gel. The effect of moisture content and particle size on the sorption rate and apparent diffusivity were determined. The effect of charging on time variation of pressure was evaluated and used for correction on all sorption data.

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