scholarly journals Analysis of Heat Transfer in Metal Hydride Based Hydrogen Separation

10.2172/14082 ◽  
1999 ◽  
Author(s):  
W.H. Jr. Fleming
Keyword(s):  
Heat Transfer ◽  
Metal Hydride ◽  
Hydrogen Separation

scholarly journals Analysis of the Heat Balance of a Metal Hydride Separator Used for the Separation of Hydrogen from Syngas

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 251
Author(s):  
Tomáš Brestovič ◽  
Marián Lázár ◽  
Natália Jasminská ◽  
Jozef Živčák ◽  
Lukáš Tóth ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Metal Hydride ◽  
Heat Balance ◽  
Alloy Powder ◽  
Hydrogen Absorption ◽  
Heat Removal ◽  
Hydrogen Separation ◽  
Thermal Recovery ◽  
Field Homogeneity

The present article discusses the potential for hydrogen separation using a metal hydride separator, which facilitates the generation of hydrogen contained in syngas following the thermal recovery of wastes. The article provides a detailed description of the separator heat balance using analytical calculations and optimised calculations, and by applying numerical methods. The proposed concept of a separator intended for hydrogen separation from syngas offers a solution to a problem associated with the use of metal hydride alloy powders; in particular, their low thermal conductivity. In order to eliminate big temperature differences in the alloy, a heat transfer intensifier was implemented in the metal hydride alloy volume; the intensifier was made of metal and exhibited high thermal conductivity. For the purpose of comparing the thermal fields, the first stage comprised the creation of a numerical simulation of hydrogen absorption without the use of an intensifier. Subsequently, three different geometries were created for an intensifier intended to remove heat from the metal hydride alloy powder towards the separator cover, and the effects of these three geometries were analysed. The implementation of heat transfer intensifiers into the metal hydride alloy powder improved the heat removal by as much as 43.9% and increased the thermal field homogeneity by 77%. A result of the heat removal optimisation was an increase in the hydrogen absorption kinetics and the efficiency of the separator operation.

Heat Transfer in High-Pressure Metal Hydride Systems

2009 ◽  
Vol 16 (2) ◽  
pp. 189-203 ◽  
Author(s):  
Kyle C. Smith ◽  
Yuan Zheng ◽  
Timothy S. Fisher ◽  
Timothee L. Pourpoint ◽  
Issam Mudawar
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Metal Hydride

scholarly journals The Impact of Active and Passive Thermal Management on the Energy Storage Efficiency of Metal Hydride Pairs Based Heat Storage

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3006
Author(s):  
Serge Nyallang Nyamsi ◽  
Ivan Tolj
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Management ◽  
Metal Hydride ◽  
Heat Storage ◽  
Energy Storage Density ◽  
Storage Efficiency ◽  
Transfer Enhancement ◽  
Storage Density ◽  
Energy Storage Efficiency

Two-tank metal hydride pairs have gained tremendous interest in thermal energy storage systems for concentrating solar power plants or industrial waste heat recovery. Generally, the system’s performance depends on selecting and matching the metal hydride pairs and the thermal management adopted. In this study, the 2D mathematical modeling used to investigate the heat storage system’s performance under different thermal management techniques, including active and passive heat transfer techniques, is analyzed and discussed in detail. The change in the energy storage density, the specific power output, and the energy storage efficiency is studied under different heat transfer measures applied to the two tanks. The results showed that there is a trade-off between the energy storage density and the energy storage efficiency. The adoption of active heat transfer enhancement (convective heat transfer enhancement) leads to a high energy storage density of 670 MJ m−3 (close to the maximum theoretical value of 755.3 MJ m−3). In contrast, the energy storage efficiency decreases dramatically due to the increase in the pumping power. On the other hand, passive heat transfer techniques using the bed’s thermal conductivity enhancers provide a balance between the energy storage density (578 MJ m−3) and the energy efficiency (74%). The utilization of phase change material as an internal heat recovery medium leads to a further reduction in the heat storage performance indicators (142 MJ m−3 and 49%). Nevertheless, such a system combining thermochemical and latent heat storage, if properly optimized, can be promising for thermal energy storage applications.

scholarly journals Tank Design for On-Board Hydrogen Storage in Metal Hydrides

2008 ◽  
Author(s):  
Karelle Couturier ◽  
Farida Joppich ◽  
Antje Wo¨rner ◽  
Rainer Tamme
Keyword(s):  
Heat Transfer ◽  
Metal Hydride ◽  
Storage Tank ◽  
Internal Heat ◽  
Transfer Model ◽  
Cooling Fluid ◽  
Internal Heat Exchanger ◽  
Tank Design ◽  
Technical Solutions ◽  
Charging Dynamics

The aim of this work is to reduce the refueling time of a metal hydride storage tank by improving its design, taking in account the total volumetric and mass capacity of the tank. A heat and mass transfer model is proposed and solved to obtain the charging curve for 1 kg hydrogen in a LaNi5 reference storage tank. Compared to gas transport and reaction kinetics, heat transfer is found to limit the hydrogen charging dynamics of the storage tank. To improve the refueling time, it is found to be necessary to increase first of all the heat transfer inside the metal hydride bed, and subsequently the heat transfer from the metal hydride bed to the cooling fluid. Technical solutions such as the implementation of aluminum foam and/or internal heat exchanger tubes are investigated. By combining both solutions, the refueling time can be reduced from 400 minutes (reference tank) to 15 minutes. The tank volume still meets the DOE targets, but its mass remains a problem. Therefore, new materials with improved gravimetric capacity have to be developed. With this work it is now possible to improve the tank design for newly developed storage materials and to evaluate their potential for technical applications.

scholarly journals Heat and mass transfer in a metal hydride reactor: combining experiments and mathematical modelling

2021 ◽  
Vol 2057 (1) ◽  
pp. 012122
Author(s):  
D O Dunikov ◽  
V I Borzenko ◽  
D V Blinov ◽  
A N Kazakov ◽  
I A Romanov ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Mass Flow ◽  
Metal Hydride ◽  
Porous Metal ◽  
Control Device ◽  
Variable Permeability ◽  
Flow Control Device ◽  
Porous Domain

Abstract Heat transfer in porous metal hydride (MH) beds determines efficiency of MH devices. We present a COMSOL Multiphysics numerical model and experimental investigation of heat and mass transfer in a MH reactor filled with 4.69 kg of AB5 type alloy (Mm0.8La0.2Ni4.1Fe0.8Al0.1). To achieve an agreement between the model and experiments it is necessary to include a flow control device (inlet valve or flow regulator) into the model. We propose a simplified and easy-to-calculate boundary condition based on a porous domain with variable permeability at reactor inlet. The permeability of the domain is connected with hydrogen mass flow by a PID controller. Thus, boundary conditions for the inlet pressure and mass flow are coupled and heat transfer inside the reactor could be calculated without additional assumptions applied to heat and mass transfer in the MH bed.

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