scholarly journals Absorption of Hydrogen in the HBond©9000 Metal Hydride Tank

2018 ◽  
Vol 6 (11) ◽  
pp. 15-20
Author(s):  
Lukas Toth ◽  
Tomas Brestovic ◽  
Natalia Jasminska
Keyword(s):  
Specific Heat ◽  
Present Article ◽  
Metal Hydride ◽  
Hydrogen Absorption ◽  
Release Kinetics ◽  
Hydrogen Desorption ◽  
Intermetallic Alloy ◽  
Gas Pressure ◽  
Hydrogen Release ◽  
Absorption Of Hydrogen

The present article describes the measurements of hydrogen absorbed into an intermetallic alloy. The process of hydrogen absorption into a metal hydride tank is accompanied with generating heat that must be removed during the process. If the tank is not cooled, the gas pressure rapidly increases and even with a small amount of the stored hydrogen the pressure exceeds the permissible value. By contrast, during hydrogen desorption it is required to supply the same amount of specific heat to avoid a significant decrease in pressure which would result in a decrease in hydrogen release kinetics.  

scholarly journals Comparing hydrogen absorption kinetics of the samples of intermetallic compound and metal hydride compact on its basis

2021 ◽  
Vol 2057 (1) ◽  
pp. 012043
Author(s):  
I A Romanov ◽  
V I Borzenko ◽  
A N Kazakov
Keyword(s):  
Intermetallic Compound ◽  
Metal Hydride ◽  
Hydrogen Absorption ◽  
Reaction Rate ◽  
Nickel Foam ◽  
High Confidence ◽  
Compact Sample ◽  
Kinetics Of ◽  
Rate Controlling Step ◽  
Absorption Of Hydrogen

Abstract This work is devoted to an experimental study and comparison of the kinetics of hydrogen absorption by an intermetallic compound LaNi4.4Al0.3Fe0.3 in form of pure intermetallic compound free backfill and a compact based on it obtained by cold pressing with a spiral matrix of nickel-foam. To calculate the kinetic parameters of the hydrogen absorption reaction, the initial rates method is used. The PCT absorption isotherms are measured at temperatures of 313, 333, and 353 K. The experimental data are described with quite high confidence by the chosen model, which assumes that the reaction rate controlling step is the dissociative absorption of hydrogen on the surface of the a-phase. The rate of hydrogen absorption increases with increasing pressure drop and temperature. It is shown that the rate of hydrogen absorption by the sample of pure IMC is significantly less dependent on temperature compared to the compact sample. In addition, the reaction rate at temperatures of 313 and 333 K is higher for the free backfill sample, and at 353 K it is higher for the metal hydride compact. The values of the absorption constant and the activation energy of the hydrogen absorption reaction are determined for both samples.

scholarly journals Crystallization Process, Structure and Hydrogen Absorption and Desorption Properties of MgxNi10 (x = 20.5-26.5) Alloys with Hypereutectic Composition

2021 ◽  
pp. X
Author(s):  
Xiaoping DONG ◽  
Yafang CHEN ◽  
Yurui MA ◽  
Xu LI
Keyword(s):  
Hydrogen Absorption ◽  
Crystallization Process ◽  
Hydrogen Desorption ◽  
Eutectic Structure ◽  
Absorption Capacity ◽  
Crystal Defects ◽  
Hydrogen Release ◽  
Hydrogen Saturation ◽  
Alloy Increase ◽  
Lower Temperature

We have analyzed crystallization process of the MgxNi10 (x = 20.5 – 26.5) alloys using phase diagram of Mg-Ni system. Their structure, atomic arrangement and crystal defects were tested by XRD, SEM and HRTEM, respectively. Hydrogenation and dehydrogenation behaviors were measured by pressure-composition-isotherm measurement. The results show that the crystallization processes of the MgxNi10 (x = 20.5 and 22.5) alloys are unlike those of the MgxNi10 (x = 24.5 and 26.5) alloys, but their room temperature microstructure all contain Mg2Ni and eutectic structure of Mg2Ni + α-Mg. The alloys are composed of Mg2Ni phase and α-Mg phase. The addition of Mg is beneficial to the formation of eutectic structure. The alloys have all good activation property. At a lower temperature, such as 200 and 250 °C, the hydrogen absorption rate and hydrogen saturation ratio are significantly lower than those of the alloy at the higher temperatures, such as 300 and 350 °C. At 350 °C, the hydrogen absorption capacity of the alloy increase and the hydrogen release efficiency of the alloy decreases with the increase of Mg content. The time of 90% of the amount of saturated hydrogen absorption and desorption of the alloys is not more than 10 and 2 minutes, respectively. The hydrogen desorption rate of the Mg22.5Ni10 alloy in the four investigated alloys is relatively large and up to 7.170 wt.%.min-1.

Synthesis by High-Energy Ball Milling of MgH2-TiFe Composites for Hydrogen Storage

2017 ◽  
Vol 899 ◽  
pp. 13-18 ◽  
Author(s):  
Ricardo Mendes Leal Neto ◽  
Rafael de Araújo Silva ◽  
Ricardo Floriano ◽  
Graziele Cristina Seco Coutinho ◽  
Railson Bolsoni Falcão ◽  
...  
Keyword(s):  
Ball Milling ◽  
Hydrogen Absorption ◽  
Hydrogen Desorption ◽  
High Energy ◽  
Control Agent ◽  
High Energy Ball Milling ◽  
Absorption Kinetics ◽  
Particle Size Reduction ◽  
Milled Sample ◽  
Energy Ball

The aim of this work is to investigate the influence of some processes variables on the microstructure and hydrogen absorption kinetics of MgH2 - X wt.% TiFe composites. Samples were synthesized by high-energy ball milling in a planetary (X = 40, 50, 60) and shaker mill (X = 40) under high-purity argon atmosphere. Commercial MgH2 instead of Mg powder was used in order to reduce adherence on the vial and balls. TiFe powder was previously produced by ball milling a mixture of TiH2 and Fe powders followed by a reaction synthesis at 600oC. Milled composites samples were characterized by XRD and SEM analysis. Milling time was preliminary investigated (X = 40) in the planetary ball mill (6 to 36h). TiFe particle size reduction was shown to be difficult since they are surrounded by MgH2 matrix. Strong particle reduction was obtained by using a shaker mill only for 2 hours and adding cyclohexane as process control agent. No reaction between MgH2 and TiFe compound was observed in any milled sample. Hydrogen absorption kinetics measurements of the as-milled samples were conducted on an Sieverts' type apparatus at room temperature after hydrogen desorption at 350oC under vacuum. The best hydrogen kinetics (3 wt% at the first hour) was attained by the planetary milled sample (36 h). Higher hydrogen capacity was observed for the sample milled in the shaker mill (4.0 wt.%), but only after 13h.

Kinetics of Hydrogen Absorption, Desorption And Permeation of Metals

CORROSION ◽  
1958 ◽  
Vol 14 (12) ◽  
pp. 34-38 ◽  
Author(s):  
T. G. OWE BERG
Keyword(s):  
Experimental Data ◽  
Reaction Mechanisms ◽  
Hydrogen Absorption ◽  
Hydrogen Gas ◽  
Acid Solutions ◽  
Dilute Acid ◽  
Energy Diffusion ◽  
Dissolved Hydrogen ◽  
Kinetics Of ◽  
Absorption Of Hydrogen

Abstract The reaction mechanisms for the absorption of hydrogen by metals from moist hydrogen gas and dilute acid solutions, for the desorption from metals of dissolved hydrogen in the presence of water and for hydrogen solubility and permeation under those conditions are discussed. Their kinetics are also given. Formulae are derived for rates and equilibria. These are compared with experimental data. The migration of H atoms in the metal is concluded to be associated with zero or nearly zero activation energy. Diffusion is rapid enough to maintain almost uniform distribution of H atoms in the metal during absorption and desorption under ordinary conditions. 3.8.4

Numerical analysis of the effects of particle radius and porosity on hydrogen absorption performances in metal hydride tank

2019 ◽  
Vol 250 ◽  
pp. 1065-1072 ◽  
Author(s):  
Xi Lin ◽  
Qi Zhu ◽  
Haiyan Leng ◽  
Hongguang Yang ◽  
Tao Lyu ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Metal Hydride ◽  
Hydrogen Absorption ◽  
Particle Radius

scholarly journals Bonding States of Hydrogen in Plasma-Deposited Hydrocarbon Films

2020 ◽  
Vol 6 (1) ◽  
pp. 3 ◽  
Author(s):  
Wolfgang Jacob ◽  
Thomas Dürbeck ◽  
Thomas Schwarz-Selinger ◽  
Udo von Toussaint
Keyword(s):  
Hydrogen Content ◽  
Release Kinetics ◽  
Binding Energies ◽  
Hydrogen Release ◽  
Linear Temperature ◽  
Exponential Factor ◽  
Temperature Ramp ◽  
Temperature Ramps ◽  
Diffusive Effects ◽  
Temperature Programmed

We applied temperature-programmed desorption (TPD) spectroscopy to study the bonding of hydrogen in amorphous hydrogenated carbon (a–C:H) films. Typical hard plasma-deposited a–C:H films with an initial hydrogen content (H/(H+C)) of about 30% were used as samples. About 85% of the initial hydrogen content is released in the form of H2, the rest in the form of hydrocarbons. Using a temperature ramp of 15 K/min, release of hydrogen starts at about 600 K with a first peak at about 875 K and a broad shoulder around 1050 K. The peak positions depend on the temperature ramp. This fact was exploited to determine the pre-exponential factor for an analytic analysis of the release spectra. This analysis revealed a pre-exponential factor of ν = 1 × 10 16 1/s, which deviates significantly from the frequently assumed prefactor 1 × 10 13 1/s. This higher prefactor leads to a shift in the determined binding energies by about +0.5 eV. Standard TPD measurements with linear temperature ramps up to 1275 K were complemented by so-called “ramp and hold” experiments with linear ramps up to certain intermediate temperatures and holding the samples for different times at these temperatures. Such experiments provide valuable additional data for investigation of the thermal behavior of the investigated films. Our experiments prove that the width of the hydrogen release spectrum is determined by a distribution of binding energies rather than release kinetics or diffusive effects. This binding energy distribution has a peak at about 3.1 eV and a shoulder at higher energies extending from about 3.6 to 3.9 eV.

Thermofluidynamic modelling of hydrogen absorption in metal hydride beds by using multiphysics software

2020 ◽  
Vol 45 (60) ◽  
pp. 34956-34971
Author(s):  
Fawzi Elhamshri ◽  
Muhammet Kayfeci ◽  
Ulaş Matik ◽  
Salaheldin Alous
Keyword(s):  
Metal Hydride ◽  
Hydrogen Absorption
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