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.

scholarly journals Моделирование процесса теплоотдачи сверхпроводящих пленок в резистивном состоянии

2021 ◽  
Vol 91 (3) ◽  
pp. 538
Author(s):  
М.А. Васютин ◽  
Н.Д. Кузьмичев ◽  
Д.А. Шилкин
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Thermal Conductivity ◽  
Low Temperatures ◽  
Heat Removal ◽  
Superconducting Films ◽  
Resistive State ◽  
Additional Heat ◽  
Film Substrate ◽  
Main Factor

The analysis of heat transfer in the contact-film-substrate system under conditions when the heat removal from the sample to the substrate is insufficient to ensure that the sample is not overheated. For low temperatures, a method is proposed for increasing the heat removal from thin-film samples by passing a high-density electric current through them. The property of an anomalously high thermal conductivity of copper at temperatures from 5 to 50 K was used as the main factor in enhancing heat removal. The heat equation for the film-substrate system was numerically solved under the condition of additional heat transfer to potential contacts. It has been shown that beryllium bronze contacts can provide efficient heat removal from samples of superconducting films in a resistive state under conditions of strong Joule heat release.

THERMAL CONDUCTIVITY OF COMPOSITE POLYPROPYLENE/CARBON NANOFIBRES

2019 ◽  
Vol 1 (7) ◽  
pp. 72-76
Author(s):  
A. S. Stepashkina ◽  
M. Yu. Egorov ◽  
R. N. Tselms ◽  
T. P. Mishura
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Transfer Process ◽  
Heat Removal ◽  
Heat Transfer Process ◽  
Polymer Composite Material ◽  
Heat Conducting ◽  
Carbon Nanofibres ◽  
Linear Character ◽  
Filler Mass

The polymer composite material based on polypropylene (PP) matrix and vapor grown carbon fibers (VGCF) as filler was received by the melt-technology. Dependences of the thermal conductivity on the filler mass fraction and temperature were experimentally obtained. Such dependences have a nearly linear character. It is shown that the material heat-conducting properties don’t depend on the sample geometry. It is found out that in case the concentration of VGCF is more than 5% the material can be used for heat removal in electrical and electronic devices. To describe the heat transfer process a model was built based on the multichannel conduction problem. It allows describing the heat transfer process in composite materials with sharply differing heat-conducting properties of the components taking into account such material characteristics as density, heat capacity, heat conduction, and heat flow velocity.

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 Analysis of Heat Balance of MH Separator

2020 ◽  
Vol 328 ◽  
pp. 03014
Author(s):  
Lukáš Tóth ◽  
Tomáš Brestovič ◽  
Natália Jasminská ◽  
Marián Lázár
Keyword(s):  
Metal Hydride ◽  
Heat Balance ◽  
Plasma Reactor ◽  
Hydrogen Separation ◽  
Thermal Balance ◽  
Equipment Operation ◽  
Gasification Process ◽  
Heating And Cooling ◽  
Synthetic Gas ◽  
Waste Gasification

The paper deals with the thermal balance of a metal hydride separator, primarily a tank containing a metal hydride alloy subjected to heating and cooling processes caused by absorption and desorption. As during the equipment operation it is necessary to ensure heating and cooling, the amount of the required heat to be supplied and removed must be identified. The article also deals with hydrogen separation from undesired components of synthetic gas which is formed in a plasma reactor during the waste gasification process.

scholarly journals Design and calculation of heat transfer of the passive cooling modules for low-pressure hydrogen vessels

2021 ◽  
Vol 9 (11) ◽  
pp. 212-217
Author(s):  
Marián Lázár ◽  
Filip Duda ◽  
Ľubomíra Kmeťová ◽  
Natália Jasminská ◽  
Šimon Hudák
Keyword(s):  
Heat Transfer ◽  
Metal Hydride ◽  
Hydrogen Absorption ◽  
Energy Intensity ◽  
Hydrogen Gas ◽  
Current Level ◽  
Temperature Management ◽  
Passive Cooling ◽  
Science And Research ◽  
Pressure Hydrogen

This paper deals with the issue of improving the temperature management of a metal hydride tank to reduce the energy intensity of cooling. The problem of absorption and adsorption of hydrogen gas in metals, cooling of metal hydride tanks in the process of hydrogen absorption while protecting the current level of development of science and research for this area is analysed. The work also deals with numerical and experimental verification of a prototype metal hydride tank with passive cooling.

scholarly journals HYDROGEN ABSORPTION/DESORPTION IN A METAL HYDRIDE REACTOR ACCOUNTING FOR VARIED EFFECTIVE THERMAL CONDUCTIVITY

2011 ◽  
Vol 19 (2) ◽  
Author(s):  
Chih-Yuan Wang ◽  
Hwa-Chong Tien ◽  
San-Der Chyou ◽  
Nang-Nong Huang ◽  
Shing-Hoa Wang
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Metal Hydride ◽  
Hydrogen Absorption

scholarly journals Design of internal heat transport intensifier for metal hydride storage tank

2021 ◽  
Vol 9 (11) ◽  
pp. 196-202
Author(s):  
Filip Duda ◽  
Šimon Hudák ◽  
Tomáš Brestovič ◽  
Marián Lázár
Keyword(s):  
Heat Transfer ◽  
Metal Hydride ◽  
Thermal Field ◽  
Internal Heat ◽  
Heat Removal ◽  
Longitudinal Axis ◽  
Equilibrium Temperature ◽  
Equilibrium Pressure ◽  
Ansys Cfx ◽  
Potential Improvement

The present article deals with potential improvement of heat removal from the centre of a metal hydride tank towards the tank’s periphery while using passive heat transfer modules. Passive cooling elements are used in order to improve heat removal from the centre of a tank towards its peripheral parts. This increases the homogeneity of the thermal field in a tank’s cross-section, which is perpendicular to the longitudinal axis. Moreover, the use of such elements improves the kinetics of hydrogen absorption into an alloy, in particular by prolonging the time to an equilibrium temperature of the alloy for a particular equilibrium pressure, which may shorten the time to a tank being 100% filled with hydrogen. The article describes four different designs of internal heat transfer intensifiers, which are aimed at improving the thermal field distribution inside the tank and their theoretical impact on the thermal field, which was examined using Ansys CFX software.

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