CHARACTERIZING THE HYDROGEN TRANSPORT PROPERTIES OF RUBBERY POLYMERS BY GRAVIMETRIC ANALYSIS

2021 ◽  
Author(s):  
Jae Kap Jung ◽  
In Gyoo Kim ◽  
Sang Koo Jeon ◽  
Ki Soo Chung
Keyword(s):  
Transport Properties ◽  
High Pressures ◽  
Hydrogen Gas ◽  
Ex Situ ◽  
Total Charge ◽  
Hydrogen Energy ◽  
Gravimetric Analysis ◽  
Butadiene Rubber ◽  
Sample Shape ◽  
Rubbery Polymers

ABSTRACT We develop an ex situ technique to quantitatively analyze the transport properties of hydrogen gas dissolved under high pressure in rubbery polymers, such as cylindrical and spherical samples of nitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), and fluoroelastomer (FKM), which are potential sealing materials for hydrogen energy infrastructures. The technique consists of real-time gravimetric measurements during the desorption of hydrogen gas from samples using an electronic balance and a self-developed analysis program to determine the total charge (CH0), diffusivity (D), solubility (S) and permeability (P) of hydrogen. Dual absorption behavior is found for all three rubbers as the charging pressure increases. CH0 follows Henry's law at low pressures of up to ∼25 MPa, whereas the Langmuir model applies at high pressures. No significant pressure, size, or shape dependences are observed for D and P. The measured P values are consistent with those from the literature within the combined uncertainty evaluated. The effect of a carbon black filler mixed into rubber is discussed with respect to S and D. This method can be applicable as a standard test for the transport properties versus the pressure of various polymers irrespective of sample shape.

Metal Hydride Reactor Design Optimization for Hydrogen Energy Storage

2016 ◽  
Vol 708 ◽  
pp. 85-93 ◽  
Author(s):  
Vamsi Krishna Kukkapalli ◽  
Sun Woo Kim
Keyword(s):  
Heat Transfer ◽  
Metal Hydride ◽  
Hydrogen Absorption ◽  
High Pressures ◽  
Hydrogen Generation ◽  
Renewable Energy Sources ◽  
Hydrogen Gas ◽  
Attractive Alternative ◽  
Hydrogen Energy ◽  
Metal Hydride Alloys

As hydrogen generation technologies using renewable energy sources are being developed, considerable attention is paid to storage and transportation of hydrogen gas. Metal hydride alloys are considered as promising materials because they are viewed as an attractive alternative to conventional hydrogen storage cylinders and mechanical hydrogen compressors. Compared to storing in a classic gas cylinder, which requires compression of hydrogen at high pressures, metal hydride alloys can store the same amount of hydrogen at nearly room pressure. However, this hydrogen absorption necessitates an effective way to reject the heat released from the exothermic hydriding reaction. In this paper, fin structures are employed to enhance the heat transfer of metal hydride alloys in a cylindrical reactor. Numerical simulations are performed based on a multiple-physics modeling to analyze the transient heat transfer during the hydrogen absorption process. The objective is to minimize the time elapsed for the process and to reduce the hotspot temperature by determining the number and shape of rectangular fins while the total volume of fins used are fixed. The simulation results show that the more fins are applied the better heat transfer is achieved and that there exists an optimal length of the fins.

scholarly journals Impedance spectroscopy for in situ and real-time observations of the effects of hydrogen on nitrile butadiene rubber polymer under high pressure

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jae Kap Jung ◽  
Sang Koo Jeon ◽  
Kyu-Tae Kim ◽  
Chang Hoon Lee ◽  
Un Bong Baek ◽  
...  
Keyword(s):  
High Pressure ◽  
Impedance Spectroscopy ◽  
Real Time ◽  
High Pressures ◽  
Hydrogen Gas ◽  
Physicochemical Interaction ◽  
Butadiene Rubber ◽  
Current Conservation ◽  
Nitrile Butadiene Rubber

Abstract Nondestructive impedance spectroscopy (IS) was developed and demonstrated to detect the effects of hydrogen on nitrile butadiene rubber exposed to hydrogen gas (H2) at high pressures up to 10 MPa. IS was applied to obtain an in situ and real-time quantification of H2 penetration into and its desorption out of rubber under high pressure. The diffusion coefficients of H2 were also obtained from the time evolution of the capacitance, which were compared with those obtained by thermal desorption gas analysis. The in situ measurements of the capacitance and the dissipation factor under various pressures during cyclic stepwise pressurization and decompression demonstrated the diffusion behaviour of H2, the phase of the rubber under high pressure, the transport properties of H2 gas, and the physicochemical interaction between H2 and the rubber. These phenomena were supported by a COMSOL simulation based on the electric current conservation equation and scanning electron microscopy (SEM) observations.

scholarly journals Slow Strain Rate Testing of Ti-6Al-4V Alloy in Hydrogen Gas at High Pressures and High Temperatures

2017 ◽  
Vol 58 (6) ◽  
pp. 886-891 ◽  
Author(s):  
Kenichi Koide ◽  
Toshirou Anraku ◽  
Akihiro Iwase ◽  
Hiroyuki Inoue
Keyword(s):  
Strain Rate ◽  
High Temperatures ◽  
High Pressures ◽  
Hydrogen Gas ◽  
Slow Strain Rate ◽  
Slow Strain Rate Testing ◽  
Rate Testing

Effects of hydrogen on the microstructure and microchemistry of Ti3Al – Nb intermetallics at high temperatures and high pressures

1996 ◽  
Vol 11 (9) ◽  
pp. 2186-2197 ◽  
Author(s):  
H. Z. Xiao ◽  
I. M. Robertson ◽  
H. K. Birnbaum
Keyword(s):  
Solid Solution ◽  
High Temperatures ◽  
High Pressures ◽  
Chemical Potential ◽  
Substitutional Solid Solution ◽  
Hydrogen Gas ◽  
Solid Solution Phase ◽  
Face Centered Cubic ◽  
Fine Grained ◽  
Surrounding Matrix

The microstructural and microchemical changes produced in a Ti–25Al–10Nb–3V–1Mo alloy (at. %) by charging at high temperatures in high pressures of hydrogen gas have been studied using transmission electron microscopy (TEM) and x-ray methods. Hydrides incorporating all of the substitutional solutes that formed during charging have a face-centered cubic (fcc) structure and exhibit either a plate or fine-grained morphology. With increasing hydrogen content, the size of the hydrides decreases and their microchemistry changes as they approach the stable binary hydride, TiH2. Rejection of substitutional solute elements from the hydride produces changes in the microchemistry, and consequently in the crystal structure, of the surrounding matrix. In alloys containing 50 at. % H, this solute redistribution results in the formation of an orthohombic substitutional solid solution phase containing increased levels of Nb. The driving force of this redistribution of solutes is the reduction in the chemical potential of the system as the amount of the most stable hydride, TiH2, forms. The hydrides reverted to a solid solution on annealing in vacuum at 1073 K, and the original microchemistry of the alloy was restored. Reversion from the hydride structure to the original α2 ordered DO19 structure proceeds via a disordered HCP phase.

Development of an in situ synchrotron X-ray total scattering setup under pressurized hydrogen gas

2018 ◽  
Vol 51 (3) ◽  
pp. 796-801 ◽  
Author(s):  
Kouji Sakaki ◽  
Hyunjeong Kim ◽  
Akihiko Machida ◽  
Tetsu Watanuki ◽  
Yoshinori Katayama ◽  
...  
Keyword(s):  
Pair Distribution Function ◽  
Hydrogen Gas ◽  
Ex Situ ◽  
Sample Holder ◽  
Hydrogen Storage Materials ◽  
X Ray Diffraction ◽  
Total Scattering ◽  
X Ray ◽  
Diffraction Patterns

This article describes the development of an in situ gas-loading sample holder for synchrotron X-ray total scattering experiments, particularly for hydrogen storage materials, designed to collect diffraction and pair distribution function (PDF) data under pressurized hydrogen gas. A polyimide capillary with a diameter and thickness of 1.4 and 0.06 mm, respectively, connected with commercially available Swagelok fittings was used as an in situ sample holder. Leakage tests confirmed that this sample holder allows 3 MPa of hydrogen gas pressure and 393 K to be achieved without leakage. Using the developed in situ sample holder, significant background and Bragg peaks from the sample holder were not observed in the X-ray diffraction patterns and their signal-to-noise ratios were sufficiently good. The PDF patterns showed sharp peaks in the r range up to 100 Å. The results of Rietveld and PDF refinements of Ni are consistent with those obtained using a polyimide capillary (1.0 mm diameter and 0.04 mm thickness) that has been used for ex situ experiments. In addition, in situ synchrotron X-ray total scattering experiments under pressurized hydrogen gas up to 1 MPa were successfully demonstrated for LaNi4.6Cu.

The Effect of Microstructure on the Hydrogen-Assisted Fatigue of Pipeline Steels

2013 ◽  
Author(s):  
Andrew J. Slifka ◽  
Elizabeth S. Drexler ◽  
Douglas G. Stalheim ◽  
Robert L. Amaro ◽  
Damian S. Lauria ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
High Pressures ◽  
Load Ratio ◽  
Fatigue Tests ◽  
Hydrogen Gas ◽  
The Other ◽  
Stress Intensity Factor Range ◽  
Pipeline Steels

Tests on the fatigue crack growth rate were conducted on four pipeline steels, two of grade API 5L-X52 and two API 5L-X70. One X52 material was manufactured in the mid-1960s and the other was manufactured in 2011. The two X70 materials had a similar vintage and chemistry, but the microstructure differs. The fatigue tests were performed in 5.5 and 34 MPa pressurized hydrogen gas, at 1 Hz and (load ratio) R = 0.5. At high pressures of hydrogen and high values of the stress intensity factor range (ΔK) there is no difference in the fatigue crack growth rates (da/dN), regardless of strength or microstructure. At low values of ΔK, however, significant differences in the da/dN are observed. The older X52 material has a ferrite-pearlite microstructure; whereas, the modern X52 has a mixture of polygonal and acicular ferrites. The X70 materials are both predominantly polygonal ferrite, but one has small amounts (∼5%) of upper bainite, and the other has small amounts of pearlite (<2%) and acicular ferrite (∼5%). We discuss the fatigue test results with respect to the different microstructures, with particular emphasis on the low ΔK regime.

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