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Sofia, Bulgaria

Chilev C.,UTCM | Lamari F.D.,University of Paris 13
International Journal of Hydrogen Energy | Year: 2016

A brief review of the different methods of hydrogen storage process for application in automobile manufacturing was presented and discussed. The hydrogen storage by adsorption on super activated carbon AX21 at various thermodynamic conditions was investigated. In order to describe the reality of the system, we planned a brief review, a discussion and modeling of the different EOS equations adapted to a hydrogen gas. Different characterization tools for obtaining the physical property of AX21 were used, among them SEM, BET and Helium displacement method at high temperature. The hydrogen storage capacity of AX21 at different temperature and pressure up to 70 MPa was investigated experimentally. In order to describe the experimental hydrogen gas excess adsorption results, the model of Chilev and a modified potential theory were selected. The comparison of the two models describing adsorption isotherms and a critical discussion of their accuracy was given. Based on the models results the absolute amount adsorbed was obtained. The difference between an absolute and an excess amount adsorbed at 77 K and 293 K was discussed. A comparison between the volumetric tank capacity obtained by pure compression and the adsorption process at both temperatures were studied. The method of hydrogen storage and optimal operating conditions were investigated. © 2015 Hydrogen Energy Publications, LLC. Source


Chilev Ch.,UTCM | Lamari F.D.,University of Paris 13 | Ljutzkanov L.,Bulgarian Academy of Science | Simeonov E.,UTCM | Pentchev I.,UTCM
International Journal of Hydrogen Energy | Year: 2012

The possibility of application of new materials for storage of hydrogen in automotive industry is examined Materials are active carbon AC35 in whose structure, particles from various metals: Ni, Ni + La and Ni + MM are implanted. The last mentioned material called "mixed metal MM" contains approximately 51% La, 33% Ce, 12% Nd, 4% Pr. The study of the structure of the activated carbon AC35 is related to the possibility of storing hydrogen by combining physical adsorption on the inner surface of the material and the formation of metal hydrides of these metals and hydrogen to increase the total capacity. Analyses have been conducted to establish the amounts of implanted metal particles in the inner structure of the activated carbon, as well as the change of the very structure with the purpose of determining the dominant mechanism for hydrogen retaining. Temperature profiles have been investigated into the volume of model dynamic reservoir by filling it with hydrogen. A thermodynamic analysis of the impact of thermal effects of adsorption and compression at different temperatures and flows has been made. The possibility of dynamic storage of hydrogen at 77 K and room temperature has been examined. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Source


Chilev C.,UTCM | Darkrim Lamari F.,University of Paris 13 | Kirilova E.,UTCM | Kirilova E.,University of Paris 13 | Pentchev I.,UTCM
Chemical Engineering Research and Design | Year: 2012

The adsorption data of the pure gases methane, ethylene and hydrogen on two types of zeolites and two types of activated carbon materials were measured using a volumetric method at 293. K and at pressure up to 26.8. MPa. Four different approaches were tested for description of the experimental equilibrium data. Based on the experimental data obtained by other authors at very wide range of pressure (0-650. MPa), we propose a new modeling type adsorption isotherm, describing the excess of adsorption of supercritical gases on micro porous adsorbents. The analysis was developed for the description of the phenomena minimum of adsorption isotherms at very high pressure. The concept of inflection point and its thermodynamically treatments were developed. The comparison of the different models describing adsorption isotherms allows a critical discussion of their accuracy. © 2012 The Institution of Chemical Engineers. Source

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