Russian Federation
Decarbonizing Russia: Leapfrogging from Fossil Fuel to Hydrogen
Jan 2022
Publication
We examine a different approach to complete the decarbonization of the Russian economy in a world where climate policy increasingly requires the radical reduction of emissions wherever possible. We propose an energy system that can supply solar and wind-generated electricity to fulfill demand and which accounts for intermittency problems. This is instead of the common approach of planning for expensive carbon capture and storage and a massive increase in energy efficiency and therefore a drastic reduction in energy use per unit of Gross Domestic Product (GDP). Coupled with this massive increase in alternative energy we also propose using excess electricity to generate green hydrogen. Hydrogen technology can function as storage for future electricity needs or for potential fuel use. Importantly green hydrogen can potentially be used as a replacement export for Russia’s current fossil fuel exports. The analysis was carried out using the highly detailed modeling framework the High-Resolution Renewable Energy System for Russia (HIRES-RUS) representative energy system. The modeling showed that there are a number of feasible combinations of wind and solar power generation coupled with green hydrogen production to achieve 100% decarbonization of the Russian economy.
Failure of PEM Water Electrolysis Cells: Case Study Involving Anode Dissolution and Membrane Thinning
Sep 2013
Publication
Polymer electrolyte membrane (PEM) water electrolysis is an efficient and environmental friendly method that can be used for the production of molecular hydrogen of electrolytic grade using zero-carbon power sources such as renewable and nuclear. However market applications are asking for cost reduction and performances improvement. This can be achieved by increasing operating current density and lifetime of operation. Concerning performance safety reliability and durability issues the membrane-electrode assembly (MEA) is the weakest cell component. Most performance losses and most accidents occurring during PEM water electrolysis are usually due to the MEA. The purpose of this communication is to report on some specific degradation mechanisms that have been identified as a potential source of performance loss and membrane failure. An accelerated degradation test has been performed on a MEA by applying galvanostatic pulses. Platinum has been used as electrocatalyst at both anode and cathode in order to accelerate degradation rate by maintaining higher cell voltage and higher anodic potential that otherwise would have occurred if conventional Ir/IrOx catalysts had been used. Experimental evidence of degradation mechanisms have been obtained by post-mortem analysis of the MEA using microscopy and chemical analysis. Details of these degradation processes are presented and discussed.
Hydrogen Self-Ignition In Pressure Relief Devices
Sep 2009
Publication
In future pressure relief devices (PRDs) should be installed on hydrogen vehicles to prevent a hydrogen container burst in the event of a nearby fire. Weakening of the container at elevated temperature could result in such burst. In this case the role of a PRD is to release some or all of the system fluid in the event of an abnormally high pressure. The paper analyzes the possibility of hydrogen self-ignition at PRD operation and ways of its prevention.
Cell Failure Mechanisms in PEM Water Electrolyzers
Sep 2011
Publication
PEM water electrolysis offers an efficient and flexible way to produce “green-hydrogen” from renewable (intermittent) energy sources. Most research papers published in the open literature on the subject are addressing performances issues and to date very few information is available concerning the mechanisms of performance degradation and the associated consequences. Results reported in this communication have been used to analyze the failure mechanisms of PEM water electrolysis cells which can ultimately lead to the destruction of the electrolyzer. A two-step process involving firstly the local perforation of the solid polymer electrolyte followed secondly by the catalytic recombination of hydrogen and oxygen stored in the electrolysis compartments has been evidenced. The conditions leading to the onset of such mechanism are discussed and some preventive measures are proposed to avoid accidents.
Integration of Experimental Facilities: A Joint Effort for Establishing a Common Knowledge Base in Experimental Work on Hydrogen Safety
Sep 2009
Publication
With regard to the goals of the European HySafe Network research facilities are essential for the experimental investigation of relevant phenomena for testing devices and safety concepts as well as for the generation of validation data for the various numerical codes and models. The integrating activity ‘Integration of Experimental Facilities (IEF)’ has provided basic support for jointly performed experimental work within HySafe. Even beyond the funding period of the NoE HySafe in the 6th Framework Programme IEF represents a long lasting effort for reaching sustainable integration of the experimental research capacities and expertise of the partners from different research fields. In order to achieve a high standard in the quality of experimental data provided by the partners emphasis was put on the know-how transfer between the partners. The strategy for reaching the objectives consisted of two parts. On the one hand a documentation of the experimental capacities has been prepared and analysed. On the other hand a communication base has been established by means of biannual workshops on experimental issues. A total of 8 well received workshops has been organised covering topics from measurement technologies to safety issues. Based on the information presented by the partners a working document on best practice including the joint experimental knowledge of all partners with regard to experiments and instrumentation was created. Preserving the character of a working document it was implemented in the IEF wiki website which was set up in order to provide a central communication platform. The paper gives an overview of the IEF network activities over the last 5 years.
Deflagration-to-detonation Transition in Highly Reactive Combustible Mixtures
Sep 2011
Publication
High resolution numerical simulations used to study the mechanism of deflagration-to-detonation transition (DDT). The computations solved two-dimensional time-dependent reactive Navier-Stokes equations including the effects of compressibility molecular diffusion thermal conduction viscosity and detailed chemical kinetics for the reactive species with subsequent chain branching production of radicals and energy release. It is shown that from the beginning the flame accelerates exponentially producing shock waves far ahead. On the next stage the flame acceleration decreases and the shocks are formed close ahead of the flame front. The final stage is the actual transition to detonation. During the second stage a compressed unreacted mixture of increased density enters the flame producing a high pressure pulse which enhances reaction rate and the heat release in the reaction zone with a positive feedback coupling between the pressure pulse and the reaction rate. As a result the peak of the pressure pulse grows exponentially steepens into a strong shock which is coupled with the reaction zone forming the overdriven detonation. This new mechanism of DDT is different from the Zel’dovich’s gradient mechanism. The temperature gradients which appear in the form of hot spots and the like are not suitable to initiate detonation.
A Comparison Exercise on the CFD Detonation Simulation in Large Scale Confined Volumes
Sep 2009
Publication
The use of hydrogen as an energy carrier is going to widen exponentially in the next years. In order to ensure the public acceptance of the new fuel not only the environmental impact has to be excellent but also the risk management of its handling and storage must be improved. As a part of modern risk assessment procedure CFD modeling of the accident scenario development must provide reliable data on the possible pressure loads resulted from explosion processes. The expected combustion regimes can be ranged from slow flames to deflagration-to-detonation transition and even to detonation. In the last case the importance of the reliability of simulation results is particularly high since detonation is usually considered as a worst case state of affairs. A set of large-scale detonation experiments performed in Kurchatov Institute at RUT facility was selected as benchmark. RUT has typical industry-relevant characteristic dimensions. The CFD codes possibilities to correctly describe detonation in mixtures with different initial and boundary conditions were surveyed. For the modeling two detonation tests HYD05 and HYD09 were chosen; both tests were carried out in uniform hydrogen/air mixtures; first one with concentration of 20.0% vol. and the second one with 25.5% vol. In the present exercise three CFD codes using a number of different models were used to simulate these experiments. A thorough inter-comparison between the CFD results including codes models and obtained pressure predictions was carried out and reported. The results of this inter comparison should provide a solid basis for the further code development and detonation models’ validation thus improving CFD predictive capabilities.
Experimental Study of Hydrogen Releases Combustion
Sep 2009
Publication
The objectives of the presented experimental work were investigation of hydrogen release distribution and combustion modelling possible emergency situation at industry scale. Results of large scale experiments on distribution and combustion in an open and congested area are presented. The mass of hydrogen in experiments varied from 50g to 1000g with release rate from 180 to 220 g/s. Qualitative characteristics of high momentum hydrogen jet releases distribution and subsequent combustion were obtained. It is shown that obstacles slow down jet speed promote combustible mixture formation in a large volume and accelerate combustion process. The maximum overpressure in experiments with additional congested area reached ΔР = 0.4 atm. Using partial confinement of congested area turbulent combustion regime with the maximum overpressure more than 10 atm. was obtained.
Safe Storage of Compressed Hydrogen at Ambient and Cryogenic Temperatures in Flexible Glass Capillaries
Sep 2013
Publication
We have demonstrated that the strength of produced flexible quartz capillaries can be high enough to withstand the internal hydrogen pressure up to 233 MPa at normal and cryogenic temperature. According to the experimental results the cryo-compressed storage of hydrogen in the capillaries at moderate pressure can enable one to reach DOE 2015 aims for the gravimetric and volumetric capacities of vessels for the safe mobile hydrogen storage. Furthermore flexible capillaries in a bundle can probably serve as a high-pressure pipes for the transportation of gases over long distances. The developed technology of hydrogen storage can be applied to methane and hythane (H₂ - CH₄ mixture) which bridge the gap between conventional fossil fuels and the clean future of a hydrogen economy. It can be also applied to other gases i.e. air oxygen and helium-oxygen mixtures widely used in autonomic breathing devices.
Safe Testing of Catalytic Devices in Hydrogen-Air Flow
Sep 2009
Publication
Any experimental study of catalysts and catalytic recombining devices for removal of hydrogen gas from industrial environments is known to carry a risk of ignition of hydrogen. Experiments conducted in an atmosphere with a high concentration of hydrogen present a particular danger. Here a technique is reported that allows conducting such experiments with relative safety. This technique has been developed and applied by the company ‘Russian Energy Technologies’ for the last five years without any significant incident.<br/>A “Gas stream method” for testing and analysis of the characteristics of a catalyst for hydrogen/oxygen recombination is proposed. Tests with a variety of catalysts in a passive recombining device were carried out in a climatic chamber (86 l in volume) with a hydrogen/air mixture containing up to 20% (v/v) hydrogen flowing through it. The balance equation for hydrogen and oxygen flows entering reacting and exiting the chamber led to a formula for calculating the efficiency of a catalyst or a catalytic device under stationary conditions.<br/>Fluctuations in local temperatures of the catalyst and other parts of the chamber along with variation in the concentration of hydrogen gave the authors an insight into the thermal regime of an active catalyst. This enabled them to develop new catalysts for removal of hydrogen from the environment using industrial recombining devices.
High-pressure PEM Water Electrolysis and Corresponding Safety Issues
Sep 2009
Publication
In this paper safety considerations related to the operation of proton-exchange membrane (PEM) water electrolysers (hydrogen production capacity up to 1 Nm3/h and operating pressure up to 130 bars) are presented. These results were obtained in the course of the GenHyPEM project a research program on high-pressure PEM water electrolysis supported by the European Commission. Experiments were made using a high-pressure electrolysis stack designed for operation in the 0–130 bars pressure range at temperatures up to 90 °C. Besides hazards related to the pressure itself hydrogen concentration in the oxygen gas production and vice-versa (resulting from membrane crossover permeation effects) have been identified as the most significant risks. Results show that the oxygen concentration in hydrogen at 130 bars can be as high as 2.66 vol %. This is a value still outside the flammability limit for hydrogen–oxygen mixtures (3.9–95.8 vol %) but safety measures are required to prevent explosion hazards. A simple model based on the diffusion of dissolved gases is proposed to account for gas cross-permeation effects. To reduce contamination levels different solutions are proposed. First thicker membranes can be used. Second modified or composite membranes with lower gas permeabilities can be used. Third as reported earlier external catalytic gas recombiners can be used to promote H2/O2 recombination and reduce contamination levels in the gas production. Finally other considerations related to cell and stack design are also discussed to further reduce operation risks.
Hydrogen-Air Explosive Envelope Behaviour in Confined Space at Different Leak Velocities
Sep 2009
Publication
The report summarizes experimental results on the mechanisms and kinetics of hydrogen-air flammable gas cloud formation and evolution due to foreseeable (less than 10-3 kg/sec) hydrogen leaks into confined spaces with different shapes sizes and boundary conditions. The goals were - 1) to obtain qualitative information on the basic gas-dynamic patterns of flammable cloud formation at different leak velocities (between 935 and 905 m/sec) for a fixed leak flowrate and 2) to collect quantitative data on spatial and temporal characteristics of the revealed patterns. Data acquisition was performed using a spatially distributed reconfigurable net of 24 hydrogen gauges with short response time. This experimental innovation permits to study spatial features of flammable cloud evolution in detail which previously was attainable only from CFD computations. Two qualitatively different gas dynamic patterns were documented for the same leak flowrate. In one limiting case (sufficiently low speed of leak) the overall gas-dynamic pattern can be described by the well-known “filling box” model. In another limited case (high velocity of leak) it is proposed to describe the peculiarities of gas-dynamic behavior of flammable cloud by the term of a “fading up box” model. From the safety view point the “fading up box” case is more hazardous than the “filling box” case. Differences in macroscopic and kinetic behavior which are essential for safety provision are presented. Empirical non-dimensional criterion for discrimination of the two revealed basic patterns for hydrogen leaks into confined spaces with comparable length scale is proposed. The importance of the revealed “fading up box” gas-dynamic pattern is discussed for development of an advanced hydrogen gauges system design and safety criteria.
Experimental Study of Explosion Wave Propagation in Hydrogen-Air Mixtures of Variable Compositions
Sep 2009
Publication
Results are given of experimental study of propagation of explosion waves in hydrogen-air mixtures of different compositions under conditions of cumulation. The investigations are performed in a setup consisting of two parts namely the upper part in the form of a metal cone and the lower part in the form of a rubber envelope hermetically attached to the cone. The upper and lower parts of the experimental setup are separated by a thin rubber film and may be filled with hydrogen-air mixtures of different compositions.
Estimation of Uncertainty in Risk Assessment of Hydrogen Applications
Sep 2011
Publication
Hydrogen technologies such as hydrogen fuelled vehicles and refuelling stations are being tested in practice in a number of projects (e.g. HyFleet-Cute and Whistler project) giving valuable information on the reliability and maintenance requirements. In order to establish refuelling stations the permitting authorities request qualitative and quantitative risk assessments to show the safety and acceptability in terms of failure frequencies and respective consequences. For new technologies not all statistical data can be established or are available in good quality causing assumptions and extrapolations to be made. Therefore the risk assessment results contain varying degrees of uncertainty as some components are well established while others are not. The paper describes a methodology to evaluate the degree of uncertainty in data for hydrogen applications based on the bias concept of the total probability and the NUSAP concept to quantify uncertainties of new not fully qualified hydrogen technologies and implications to risk management.
Syngas Explosion Reactivity in Steam Methane Reforming Process
Sep 2013
Publication
During the synthesis of hydrogen by methane steam reforming mixtures composed of H2 CH4 CO and CO2 are produced in the process. In this work the explosion reactivity of these mixtures on the basis of detonation cell size and laminar flame speed is calculated using a reactant assimilation simplification and a kinetic approach. The detonation cells width are calculated using the Cell_CH Kurchatov institute method and the laminar flame velocities are calculated with Chemkin Premix using different detailed chemical kinetic mechanisms. These calculations are used to define if these mixtures could be considered having a medium or a high reactivity for risk assessment in case of leak in the hydrogen plants.
Catalysts for Hydrogen Removal: Kinetic Paradox and Functioning at High Concentration of Hydrogen
Sep 2009
Publication
Platinum metals dispersed on a porous carrier e.g. -Al2O3 are used as catalysts for removal of small amounts of hydrogen from the air where the excess of oxygen is significant.<br/>The recombination reaction of H2 and O2 on smooth platinum proceeds at a high rate only in gas mixes with an excess of hydrogen. When the concentration of oxygen exceeds that of hydrogen in terms of stoichiometric ratio the process slows down sharply and eventually stops completely. In research undertaken at the Karpov Institute of Physical Chemistry (Moscow) forty years ago the electrochemical mechanism of red-ox reactions was proposed as an explanation for this inhibition by excess oxygen. The results of ellipsometric analysis pointed to the formation of a protective monolayer of PtO molecules on the Pt surface in an oxygen-rich atmosphere. It was observed that the recombination reaction proceeds at a high rate with the use of a porous catalyst at any concentrations of reactant gases. The reason for that lies in the mechanism of the catalysis: the reaction proceeds at a certain depth in the porous body of the catalyst. Hydrogen which has higher mobility penetrates in larger quantity than oxygen thus creating there the stoichiometric excess. To test the proposed mechanism of recombination the catalytic reaction was studied ) with porous carriers of various thicknesses and b) with metal grids of various porosities covering the catalyst. The data obtained have confirmed unequivocally the earlier hypothesis of hydrogenation of a porous catalyst.<br/>Such insight has allowed the authors to develop more effective prototypes of catalyst for removal of hydrogen. In particular by using a porous grid cover to remove excess heat in the reaction zone of the catalyst plate we achieved a considerable expansion of the region of hydrogen concentrations where the catalyst is both effective and reliable.
Performance-Based Requirements for Hydrogen Detection Allocation and Actuation
Sep 2009
Publication
The hydrogen detection system is a key component of the hydrogen safety systems (HSS). Any HSS forms a second layer of protection for the assets under accidental conditions when a first layer of protection - passive protection systems (separation at “safe” distance natural ventilation) are inoperable or failed. In this report a performance-based risk-informed methodology for establishing of the explicit quantitative requirements for hydrogen detectors allocation and actuation is proposed. The main steps of the proposed methodology are described. It is suggested (as a first approximation) to use in a process of quantification of a hydrogen detection system performance (from safety viewpoint) a five-tiered hierarchy namely 1) safety goals 2) risk-informed safety objectives 3) performance goal and metrics 4) rational safety criteria 5) safety factors. Unresolved issues of the proposed methodology of Safety Performance Analysis for development of the risk-informed and performance based standards on the hydrogen detection systems are synopsized.<br/><br/>
Improvements in Two-Step Model of Hydrogen Detonative Combustion: Model Description and Sensitivity to its Parameters
Sep 2009
Publication
In the present paper the two-stage model of detonative combustion of hydrogen is presented. The following improvements are described: accurate description of the heat release stage of combustion; the clear physics-based procedure for calculation of the parameters of the proposed model; sample calculations of the detonation wave in hydrogen/air mixtures in wide range of conditions showing that the proposed model performs well in a wide range of conditions (pressures temperatures mixture compositions). The results of the 2D simulations of the detonation cell are presented for the hydrogen/oxygen/argon mixture as example to show the performance and accuracy of the model presented in this paper.
On the Use of Hydrogen in Confined Spaces: Results from the Internal Project InsHyde
Sep 2009
Publication
Alexandros G. Venetsanos,
Paul Adams,
Inaki Azkarate,
A. Bengaouer,
Marco Carcassi,
Angunn Engebø,
E. Gallego,
Olav Roald Hansen,
Stuart J. Hawksworth,
Thomas Jordan,
Armin Keßler,
Sanjay Kumar,
Vladimir V. Molkov,
Sandra Nilsen,
Ernst Arndt Reinecke,
M. Stöcklin,
Ulrich Schmidtchen,
Andrzej Teodorczyk,
D. Tigreat,
N. H. A. Versloot and
L. Boon-Brett
The paper presents an overview of the main achievements of the internal project InsHyde of the HySafe NoE. The scope of InsHyde was to investigate realistic small-medium indoor hydrogen leaks and provide recommendations for the safe use/storage of indoor hydrogen systems. Additionally InsHyde served to integrate proposals from HySafe work packages and existing external research projects towards a common effort. Following a state of the art review InsHyde activities expanded into experimental and simulation work. Dispersion experiments were performed using hydrogen and helium at the INERIS gallery facility to evaluate short and long term dispersion patterns in garage like settings. A new facility (GARAGE) was built at CEA and dispersion experiments were performed there using helium to evaluate hydrogen dispersion under highly controlled conditions. In parallel combustion experiments were performed by FZK to evaluate the maximum amount of hydrogen that could be safely ignited indoors. The combustion experiments were extended later on by KI at their test site by considering the ignition of larger amounts of hydrogen in obstructed environments outdoors. An evaluation of the performance of commercial hydrogen detectors as well as inter-lab calibration work was jointly performed by JRC INERIS and BAM. Simulation work was as intensive as the experimental work with participation from most of the partners. It included pre-test simulations validation of the available CFD codes against previously performed experiments with significant CFD code inter-comparisons as well as CFD application to investigate specific realistic scenarios. Additionally an evaluation of permeation issues was performed by VOLVO CEA NCSRD and UU by combining theoretical computational and experimental approaches with the results being presented to key automotive regulations and standards groups. Finally the InsHyde project concluded with a public document providing initial guidance on the use of hydrogen in confined spaces.
Full Suppression of Hydrogen Explosion Using Phlegmatization Additives- Experimental Results
Sep 2011
Publication
The paper presents results of experimental investigations of different phlegmatizator substances and its binary compounds used for full hydrogen combustion suppression. The work was performed in experimental facilities of three different scales (small medium and large) at normal initial pressure and temperature range 20 ⎯ 120 °С. Ten individual substances and six binary compounds were tested in a small scale experiments. Three individual halogen containing substances capable of full suppression of hydrogen combustion were found in a series of small scale experiments (tube length – 1 m ID – 66 mm). The minimum concentration of the most effective substance was 11% at 20°С and 14% at 120°С in a small scale experiments. Medium scale confined and large scale unconfined experiments confirmed the possibility of full combustion suppression. The minimum concentration of the most effective binary mixture was found to be 12 % at 20°С in a large scale experiments.
Hydrogen Subsonic Upward Release and Dispersion Experiments in Closed Cylindrical Vessel
Sep 2007
Publication
Report presents the preliminary experimental results on hydrogen subsonic leakage in a closed vessel under the well-controlled boundary/initial conditions. Formation of hydrogen-air gas mixture cloud was studied for a transient (10 min) upward hydrogen leakage which was followed by subsequent evolution (15 min) of explosive cloud. Low-intensity ( 0.46⋅10−3 m3/sec) hydrogen release was performed via circular (diameter 0.014 m) orifice located in the bottom part of a horizontal cylindrical vessel ( ≈4 m3). A spatially distributed net of the 24 hydrogen sensors and 24 temperature sensors was used to permanently track the time dependence of the hydrogen concentration and temperature fields in vessel. Analysis of the simultaneous experimental records for the different spatial points permits to delineate the basic flow patterns and stages of hydrogen subsonic release in closed vessel in contrast to hydrogen jet release in open environment. The quantitative data were obtained for the averaged speeds of explosive cloud envelop (50% fraction of the Lower Flammability Limit (LFL)) propagation in the vertical and horizontal directions. The obtained data will be used as an experimental basis for development of the guidelines for an indoors allocation of the hydrogen sensors. Data can be also used as a new benchmark case for the reactive Computational Fluid Dynamics codes validation.
Hydrogen Storage: Thermodynamic Analysis of Alkyl-Quinolines and Alkyl-Pyridines as Potential Liquid Organic Hydrogen Carriers (LOHC)
Dec 2021
Publication
The liquid organic hydrogen carriers (LOHC) are aromatic molecules which can be considered as an attractive option for the storage and transport of hydrogen. A considerable amount of hydrogen up to 7–8% wt. can be loaded and unloaded with a reversible chemical reaction. Substituted quinolines and pyridines are available from petroleum coal processing and wood preservation or they can be synthesized from aniline. Quinolines and pyridines can be considered as potential LOHC systems provided they have favorable thermodynamic properties which were the focus of this current study. The absolute vapor pressures of methyl-quinolines were measured using the transpiration method. The standard molar enthalpies of vaporization of alkyl-substituted quinolines and pyridines were derived from the vapor pressure temperature dependencies. Thermodynamic data on vaporization and formation enthalpies available in the literature were collected evaluated and combined with our own experimental results. The theoretical standard molar gas-phase enthalpies of formation of quinolines and pyridines calculated using the quantum-chemical G4 methods agreed well with the evaluated experimental data. Reliable standard molar enthalpies of formation in the liquid phase were derived by combining high-level quantum chemistry values of gas-phase enthalpies of formation with experimentally determined enthalpies of vaporization. The liquid-phase hydrogenation/dehydrogenation reaction enthalpies of alkyl-substituted pyridines and quinolines were calculated and compared with the data for other potential liquid organic hydrogen carriers. The comparatively low enthalpies of reaction make these heteroaromatics a seminal LOHC system.
Mathematical Description of Energy Transition Scenarios Based on the Latest Technologies and Trends
Dec 2021
Publication
This work dedicated to a mathematical description of energy transition scenarios consists of three main parts. The first part describes modern trends and problems of the energy sector. A large number of charts reflecting the latest updates in energy are provided. The COVID-2019 pandemic’s impacts on the energy sector are also included. The second part of the paper is dedicated to the analysis of energy consumption and the structure of the world fuel and energy balance. Furthermore a detailed description of energy-efficient technologies is given. Being important and low-carbon hydrogen is discussed including its advantages and disadvantages. The last part of the work describes the mathematical tool developed by the authors. The high availability of statistical data made it possible to identify parameters used in the algorithm with the least squares method and verify the tool. Performing several not complicated steps of the algorithm the tool allows calculating the deviation of the average global temperature of the surface atmosphere from preindustrial levels in the 21st century under different scenarios. Using the suggested mathematical description the optimal scenario that makes it possible to keep global warming at a level below 1.7 ◦C was found.
Hydrogen Safety Aspects Related to High Pressure - PEM Water Electrolysis
Sep 2007
Publication
Polymer electrolyte membrane (PEM) water electrolysis has demonstrated its potentialities in terms of cell efficiency (energy consumption ≈ 4.0-4.2 kW/Nm3 H2) and gas purity (> 99.99% H2). Current research activities are aimed at increasing operating pressure up to several hundred bars for direct storage of hydrogen in pressurized vessels. Compared to atmospheric pressure electrolysis high-pressure operation yields additional problems especially with regard to safety considerations. In particular the rate of gases (H2 and O2) cross-permeation across the membrane and their water solubility both increase with pressure. As a result gas purity is affected in both anodic and cathodic circuits and this can lead to the formation of explosive gas mixtures. To prevent such risks two different solutions reported in this communication have been investigated. First the chemical modification of the solid polymer electrolyte in order to reduce cross-permeation phenomena. Second the use of catalytic H2/O2 recombiners to maintain H2 levels in O2 and O2 levels in H2 at values compatible with safety requirements.
Effect of Hydrogen on the Deformation Behavior and Localization of Plastic Deformation of the Ultrafine-Grained Zr–1Nb Alloy
Oct 2020
Publication
In this paper comparison studies of the hydrogen effect on the structural and phase state deformation behavior and mechanical properties of the fine- (average grain size 4 µm) and ultrafine-grained (average element size 0.3 and 0.4 µm) Zr–1wt.%Nb (hereinafter Zr–1Nb) alloy under tension at temperatures in the range of 293–873 K were conducted. The formation of an ultrafine-grained structure is established to increase the strength characteristics of the Zr–1Nb alloy by a factor of 1.5–2 with a simultaneous reduction of its resistance to the localization of plastic deformation at the macro level and the value of deformation to failure. The presence of hydrogen in the Zr–1Nb alloy in the form of a solid solution and hydride precipitates increases its resistance to the localization of plastic deformation at the macro level if the alloy has an ultrafine-grained structure and decreases if the structure of the alloy is fine-grained. In the studied temperature range the Zr–1Nb alloy in the ultrafine-grained state has a higher resistance to hydrogen embrittlement than the alloy in the fine-grained state.
Sensitivity to Detonation and Detonation Cellular Structure of H2-O2-AIr-H2O2 Gas Mixtures
Sep 2005
Publication
Today it is not known – neither qualitatively not quantitatively - how large the impact can be of the promoters on sensitivity to hydrogen-air detonation in hypothetical accidents at hydrogen-containing installations transport or storage facilities. Report goal is to estimate theoretically an effect of hydrogen-peroxide (as representative promoter) on sensitivity to detonation of the stoichiometric hydrogen-oxygen gas mixtures. The classical H2-O2-Ar (2:1:7) gas mixture was chosen as reference system with the well established and unambiguously interpreted experimental data. In kinetic simulations it was found that the ignition delay time is sensitive to H2O2addition for small initial H2O2concentrations and is nearly constant for the large ones. Parametric reactive CFD studies of two dimensional cellular structure of 2H2-O2-7Ar-H2O2 detonations with variable hydrogen peroxide concentration (up to 10 vol.%) were also performed. Two un-expected results were obtained. First result: detonation cell size is practically independent upon variation of initial hydrogen peroxide concentration. For practical applications it means that presence of hydrogen-peroxide did not change drastically sensitivity of the stoichiometric hydrogen-oxygen gas mixtures. These theoretical speculations require an experimental verification. Second result: for large enough initial H2O2concentrations (> 1 vol.% at least) a new element of cellular structure of steady detonation wave was revealed. It is a system of multiple secondary longitudinal shock waves (SLSW) which propagates in the direction opposite to that of the leading shock wave. Detailed mechanism of SLSW formation is proposed.
Development of Hydrogen Sensors and Recombiners
Sep 2005
Publication
Hydrogen energy is very promising as it ensures a high efficiency and ecological cleanliness of energy conversion. The goal of the present work is to provide the analysis of hydrogen safety aspects and to prescribe methods of safety operation with hydrogen. The authors conducted a hazard analysis of hydrogen operation and storage in comparison with other fuels. Good ventilation is the main hydrogen operation requirement. Besides an effective way of protection against propagation of hazards (for instance leaks) is neutralization of dangerous hydrogen-air mixtures by a method of controlled catalytic combustion inside special devices so-called recombiners [1-3]. The basis of these devices is a high porosity cell material (HPCM) activated by platinum deposition. Apart from recombiners HPCM was also applied for development of hydrogen detectors intended for measurement and analysis of hydrogen concentration for hydrogen-driven transport and objects of hydrogen infrastructure (including vapor-air media at high pressure and temperatures). A system of hydrogen safety based on hydrogen detectors and hydrogen catalytic recombiners was developed. Experimental and theoretical studies of hydrogen combustion processes heat- and mass transfer and also gas flows in catalytic-activated HPCM allowed for a design optimization of recombiners and their location. Pilot hydrogen detectors and hydrogen catalytic recombiners were fabricated and their laboratory tests were successfully performed. Thus it was indicated that on condition of following the appropriate passive and active safety measures hydrogen is just as safe as the other fuels. This conclusion represents another incentive for a transition to the hydrogen energy.
Modelling of Lean Uniform and Non-Uniform Hydrogen-Air Mixture Explosions in a Closed Vessel
Sep 2009
Publication
Simulation of hydrogen-air mixture explosions in a closed large-scale vessel with uniform and nonuniform mixture compositions was performed by the group of partners within the EC funded project “Hydrogen Safety as an Energy Carrier” (HySafe). Several experiments were conducted previously by Whitehouse et al. in a 10.7 m3 vertically oriented (5.7-m high) cylindrical facility with different hydrogen-air mixture compositions. Two particular experiments were selected for simulation and comparison as a Standard Benchmark Exercise (SBEP) problem: combustion of uniform 12.8% (vol.) hydrogen-air mixture and combustion of non-uniform hydrogen-air mixture with average 12.6% (vol.) hydrogen concentration across the vessel (vertical stratification 27% vol. hydrogen at the top of the vessel 2.5% vol. hydrogen at the bottom of the vessel); both mixtures were ignited at the top of the vessel. The paper presents modelling approaches used by the partners comparison of simulation results against the experiment data and conclusions regarding the non-uniform mixture combustion modelling in real-life applications.
Experimental and Numerical Investigation of Hydrogen Gas Auto-ignition
Sep 2007
Publication
This paper describes hydrogen self-ignition as a result of the formation of a shock wave in front of a high-pressure hydrogen gas propagating in the tube and the semi-confined space for which the numerical and experimental investigation was done. An increase in the temperature behind the shock wave leads to the ignition on the contact surface of the mixture of combustible gas with air. The required condition of combustible self-ignition is to maintain the high temperature in the mixture for a time long enough for inflammation to take place. Experimental technique was based on a high-pressure chamber inflating with hydrogen burst disk failure and pressurized hydrogen discharge into tube of round or rectangular cross section filled with air. A physicochemical model involving the gas dynamic transport of a viscous gas the detailed kinetics of hydrogen oxidation k-ω differential turbulence model and the heat exchange was used for calculations of the self-ignition of high-pressure hydrogen. The results of our experiments and model calculations show that self-ignition in the emitted jet takes place. The stable development of self-ignition naturally depends on the orifice size and the pressure in the vessel a decrease in which leads to the collapse of the ignition process. The critical conditions are obtained.
Explosion Hazard of Hydrogen-Air Mixtures in the Large Volumes
Sep 2007
Publication
The report deals with the investigation of non-stationary combustion of hydrogen-air mixtures extremely relevant to the issues of safety. Considered are the conditions of its formation and development in the tubes in the conic element and in the spherical 12-m diameter chamber. The report shows that at the formation of non-stationary combustion in the conic element in its top the pressure can develop exceeding 1000 atmospheres. It is also shown that in large closed volumes non-stationary combustion can develop from a small energy source in contrast to detonation for whose stimulation in large volumes significant power influences are required. Simultaneously in the volume a pressure can be formed by far exceeding the Chapman-Jouguet pressure in the front of stationary detonation.
Hydrogen Storage Performance of the Multi-principal-component CoFeMnTiVZr Alloy in Electrochemical and Gas–solid Reactions
Jun 2020
Publication
The single-phase multi-principal-component CoFeMnTiVZr alloy was obtained by rapid solidification and examined by a combination of electrochemical methods and gas–solid reactions. X-ray diffraction and high-resolution transmission electron microscopy analyses reveal a hexagonal Laves-phase structure (type C14). Cyclic voltammetry and electrochemical impedance spectroscopy investigations in the hydrogen absorption/desorption region give insight into the absorption/desorption kinetics and the change in the desorption charge in terms of the applied potential. The thickness of the hydrogen absorption layer obtained by the electrochemical reaction is estimated by high-resolution transmission electron microscopy. The electrochemical hydrogen storage capacity for a given applied voltage is calculated from a series of chronoamperometry and cyclic voltammetry measurements. The selected alloy exhibits good stability for reversible hydrogen absorption and demonstrates a maximum hydrogen capacity of ∼1.9 wt% at room temperature. The amount of hydrogen absorbed in the gas–solid reaction reaches 1.7 wt% at 298 K and 5 MPa evidencing a good correlation with the electrochemical results.
Research of Nanomaterials as Electrodes for Electrochemical Energy Storage
Jan 2022
Publication
This paper has experimentally proved that hydrogen accumulates in large quantities in metal-ceramic and pocket electrodes of alkaline batteries during their operation. Hydrogen accumulates in the electrodes in an atomic form. After the release of hydrogen from the electrodes a powerful exothermic reaction of atomic hydrogen recombination with a large energy release occurs. This exothermic reaction is the cause of thermal runaway in alkaline batteries. For the KSL-15 battery the gravimetric capacity of sintered nickel matrix of the oxide-nickel electrode as hydrogen storage is 20.2 wt% and cadmium electrode is 11.5 wt%. The stored energy density in the metal-ceramic matrix of the oxide-nickel electrode of the battery KSL-15 is 44 kJ/g and in the cadmium electrode it is 25 kJ/g. The similar values for the KPL-14 battery are as follows. The gravimetric capacity of the active substance of the pocket oxide-nickel electrode as a hydrogen storage is 22 wt% and the cadmium electrode is 16.9 wt%. The density of the stored energy in the active substance oxide-nickel electrode is 48 kJ/g and in the active substance of the cadmium electrode it is 36.8 kJ/g. The obtained results of the accumulation of hydrogen energy in the electrodes by the electrochemical method are three times higher than any previously obtained results using the traditional thermochemical method.
Pd Catalysts Supported on Bamboo-Like Nitrogen-Doped Carbon Nanotubes for Hydrogen Production
Mar 2021
Publication
Bamboo-like nitrogen-doped carbon nanotubes (N-CNTs) were used to synthesize supported palladium catalysts (0.2–2 wt.%) for hydrogen production via gas phase formic acid decomposition. The beneficial role of nitrogen centers of N-CNTs in the formation of active isolated palladium ions and dispersed palladium nanoparticles was demonstrated. It was shown that although the surface layers of N-CNTs are enriched with graphitic nitrogen palladium first interacts with accessible pyridinic centers of N-CNTs to form stable isolated palladium ions. The activity of Pd/N-CNTs catalysts is determined by the ionic capacity of N-CNTs and dispersion of metallic nanoparticles stabilized on the nitrogen centers. The maximum activity was observed for the 0.2% Pd/N-CNTs catalyst consisting of isolated palladium ions. A ten-fold increase in the concentration of supported palladium increased the contribution of metallic nanoparticles with a mean size of 1.3 nm and decreased the reaction rate by only a factor of 1.4.
An Extended Flamelet-based Presumed Probability Density Function for Predicting Mean Concentrations of Various Species in Premixed Turbulent Flames
Sep 2020
Publication
Direct Numerical Simulation (DNS) data obtained by Dave and Chaudhuri (2020) from a lean complex-chemistry hydrogen-air flame associated with the thin-reaction-zone regime of premixed turbulent burning are analyzed to perform a priori assessment of predictive capabilities of the flamelet approach for evaluating mean species concentrations. For this purpose dependencies of mole fractions and rates of production of various species on a combustion progress variable c obtained from the laminar flame are averaged adopting either the actual Probability Density Function (PDF) P (c) extracted from the DNS data or a common presumed β-function PDF. On the one hand the results quantitatively validate the flamelet approach for the mean mole fractions of all species including radicals but only if the actual PDF P (c) is adopted. The use of the β-function PDF yields substantially worse results for the radicals’ concentrations. These findings put modeling the PDF P (c) on the forefront of the research agenda. On the other hand the mean rate of product creation and turbulent burning velocity are poorly predicted even adopting the actual PDF. These results imply that in order to evaluate the mean species concentrations the flamelet approach could be coupled with another model that predicts the mean rate and turbulent burning velocity better. Accordingly the flamelet approach could be implemented as post-processing of numerical data yielded by that model. Based on the aforementioned findings and implications a new approach to building a presumed PDF is developed. The key features of the approach consist in (i) adopting a re-normalized flamelet PDF for intermediate values of c and (ii) directly using the mean rate of product creation to calibrate the presumed PDF. Capabilities of the newly developed PDF for predicting mean species concentrations are quantitively validated for all species including radicals.
Mathematical Modeling and Simulation of Hydrogen-fueled Solid Oxide Fuel Cell System for Micro-grid Applications - Effect of Failure and Degradation on Transient Performance
May 2020
Publication
We use a detailed solid oxide fuel cell (SOFC) model for micro-grid applications to analyze the effect of failure and degradation on system performance. Design and operational constraints on a component and system level are presented. A degrees of freedom analysis identifies controlled and manipulated system variables which are important for control. Experimental data are included to model complex degradation phenomena of the SOFC unit. Rather than using a constant value a spatially distributed degradation rate as function of temperature and current density is used that allows to study trajectory based performance deterioration. The SOFC unit is assumed to consist of multiple stacks. The failure scenario studied is the loss of one individual SOFC stack e.g. due to breakage of sealing or a series of fuel cells. Simulations reveal that degradation leads to significant drifts from the design operating point. Moreover failure of individual stacks may bring the still operating power generation unit into a regime where further failures and accelerated degradation is more likely. It is shown that system design dimensioning operation and control are strongly linked. Apart from specific quantitative results perhaps the main practical contribution are the collected constraints and the degrees of freedom analysis.
On Flame Ball-to-Deflagration Transition in Hydrogen-air Mixtures
Sep 2021
Publication
Ultra-lean hydrogen-air combustion is characterized by two phenomena: the difference in upward and downward flame propagation concentration limits and the incomplete combustion. The clear answers on the two basic questions are still absent: What is a reason and what is a mechanism for their manifestation? Problem statement and the principal research topics of the Flame Ball to Deflagration Transition (FBDT) phenomenon in gaseous hydrogen-air mixtures are presented. The non-empirical concept of the fundamental concentration limits discriminates two basic low-speed laminar combustion patterns - self-propagating locally planar deflagration fronts and drifting locally spherical flame balls. To understand - at what critical conditions and how the baric deflagrations are transforming into iso- baric flame balls? - the photographic studies of the quasi-2-dim flames freely propagating outward radially via thin horizontal channel were performed. For gradual increase of initial hydrogen concentration from 3 to 12 vol.% the three representative morphological types of combustion (star-like dendrite-like and quasi-homogeneous) and two characteristic processes of reaction front bifurcation were revealed. Key elements of the FBDT mechanism both for 2-dim and 3-dim combustion are the following. Locally spherical ""leading centres"" (drifting flame balls) are the ""elementary building blocks"" of all ultra-lean flames. System of the drifting flame balls is formed due to primary bifurcation of the pre-flame kernel just after ignition. Subsequent mutual dynamics and overall morphology of the ultra-lean flames are governed by competitive non-local interactions of the individual drifting flame balls and their secondary/tertiary/etc. bifurcations defined by initial stoichiometry."
The Microstructure Study of the Hydrogenated Titanium Specimens Tested at High Temperature Creep for Long-term Tensile Strength
Feb 2020
Publication
Experimental tests of flat titanium samples at a temperature of 450 °C stretched with a constant force up to destruction were carried out. Titanium samples were hydrogenated in the Moscow Aviation Institute laboratory to a hydrogen content of 0.1 % 0.3 % and 0.6 % by weight of the specimen and then tested in the laboratory of Lomonosov Moscow State University. From the experiments the time to failure the localization time of the deformations and the stress distribution along the longitudinal coordinate of the sample over time were obtained. A metallographic study was conducted and the phase composition was investigated in Moscow Aviation Institute. The effect of hydrogen on long-term strength mechanical characteristics and phase composition has been elucidated.
Features of the Hydrogen-Assisted Cracking Mechanism in the Low-Carbon Steel at Ex- and In-situ Hydrogen Charging
Dec 2018
Publication
Hydrogen embrittlement has been intensively studied in the past. However its governing mechanism is still under debate. Particularly the details of the formation of specific cleavage-like or quasi-cleavage fracture surfaces related to hydrogen embrittled steels are unclear yet. Recently it has been found that the fracture surface of the hydrogen charged and tensile tested low-carbon steel exhibits quasi-cleavage facets having specific smoothly curved surface which is completely different from common flat cleavage facets. In the present contribution we endeavor to shed light on the origin of such facets. For this purpose the notched flat specimens of the commercial low carbon steel were tensile tested using ex- and in-situ hydrogen charging. It is found that in the ex-situ hydrogen charged specimens the cracks originate primarily inside the specimen bulk and expand radially form the origin to the specimen surface. This process results in formation of “fisheyes” – the round-shape areas with the surface composed of curved quasi-cleavage facets. In contrast during tensile testing with in-situ hydrogen charging the cracks initiate from the surface and propagate to the bulk. This process results in the formation of the completely brittle fracture surface with the quasi-cleavage morphology - the same as that in fisheyes. The examination of the side surface of the in-situ hydrogen charged specimens revealed the straight and S-shaped sharp cracks which path is visually independent of the microstructure and crystallography but is strongly affected by the local stress fields. Nano-voids are readily found at the tips of these cracks. It is concluded that the growth of such cracks occurs by the nano-void coalescence mechanism and is responsible for the formation of fisheyes and smoothly curved quasi-cleavage facets in hydrogen charged low-carbon steel.
Vacuum vs Argon Technology for Hydrogen Measurement
Dec 2018
Publication
Within the framework of this paper we review the development of the problem of hydrogen diagnostic for metals. Metal sample enrichment techniques based on hydrogen vacuum extraction method used for a long time. Development of the industrial control technologies has led to the almost complete replacement of vacuum techniques with “atmospheric” ones. As a result systematic errors have occurred. These errors lead to multiple differences between certified and measured hydrogen concentration values for standard samples.<br/>In this paper we analyze reasons of systematic errors genesis observed for hydrogen measurements while applying the thermal conductivity cell technique. As a result we demonstrated that measurements resulting from samples heating and melting in the inert gas flow depend on its heat capacity and surface temperature of the melting pot. Due to this reason one can obtain multiple errors and even negative values for measurements of a low hydrogen concentration."
Hydrogen Accumulation and Distribution in Pipeline Steel in Intensified Corrosion Conditions
Apr 2019
Publication
Hydrogen accumulation and distribution in pipeline steel under conditions of enhanced corrosion has been studied. The XRD analysis optical spectrometry and uniaxial tension tests reveal that the corrosion environment affects the parameters of the inner and outer surface of the steel pipeline as well as the steel pipeline bulk. The steel surface becomes saturated with hydrogen released as a reaction product during insignificant methane dissociation. Measurements of the adsorbed hydrogen concentration throughout the steel pipe bulk were carried out. The pendulum impact testing of Charpy specimens was performed at room temperature in compliance with national standards. The mechanical properties of the steel specimens were found to be considerably lower and analogous to the properties values caused by hydrogen embrittlement.
Towards Unified Protocol for Par's Performance Rating and Safety Margins Assessment: Par Life-cycle Systemic Model
Sep 2021
Publication
Passive Autocatalytic Recombiners (PAR) is one of the important technical mitigation means for hydrogen combustion in the NPP containments under accident conditions. For the PWR/VVER/CANDU units the PARs execute functions important for safety - reduce the local hydrogen concentration to an acceptable level and provide the homogenization of gas composition and of temperature fields in the containment. Certification and licensing of PAR technology have been accepted for the different NPP types and in the different countries on the case-by-case basement. But a comprehensive and generally accepted terminology and procedures for PAR characterization and its performance and safety rating are still absent. As a next step in PAR's technology improvement and maturity it would be logical a development of their unified technical standardization and certification. Report is aimed to - 2) justify need in standardization of the PARs in the nuclear industry and in the hydrogen energy applications 2) define a minimal set of the notions which can be used for quantitative characterization of the of PARs throughout its life-cycle 3) formulate a systemic (generic state-machine or automata) model of PAR's states under the normal and accident conditions. After verification and validation of proposed PAR systemic model it can be used as one of ints for the development of an international standard for PAR performance and safety.
The Hydrogen Energy Infrastructure Development in Japan
Nov 2018
Publication
The actual start of the full-scale hydrogen energy infrastructure operations is scheduled to 2020 in Japan. The scope of factors and policy for the hydrogen infrastructure development in Japan is made. The paper provides observation for the major undergoing and already done projects for each link within hydrogen infrastructure chain – from production to end-user applications. Implications for the Russian energy policy are provided.
Boosting the H2 Production Efficiency via Photocatalytic Organic Reforming: The Role of Additional Hole Scavenging System
Nov 2021
Publication
The simultaneous photocatalytic H2 evolution with environmental remediation over semiconducting metal oxides is a fascinating process for sustainable fuel production. However most of the previously reported photocatalytic reforming showed nonstoichiometric amounts of the evolved H2 when organic substrates were used. To explain the reasons for this phenomenon a careful analysis of the products and intermediates in gas and aqueous phases upon the photocatalytic hydrogen evolution from oxalic acid using Pt/TiO2 was performed. A quadrupole mass spectrometer (QMS) was used for the continuous flow monitoring of the evolved gases while high performance ion chromatography (HPIC) isotopic labeling and electron paramagnetic resonance (EPR) were employed to understand the reactions in the solution. The entire consumption of oxalic acid led to a ~30% lower H2 amount than theoretically expected. Due to the contribution of the photoKolbe reaction mechanism a tiny amount of formic acid was produced then disappeared shortly after the complete consumption of oxalic acid. Nevertheless a much lower concentration of formic acid was generated compared to the nonstoichiometric difference between the formed H2 and the consumed oxalic acid. Isotopic labeling measurements showed that the evolved H2 HD and/or D2 matched those of the solvent; however using D2O decreased the reaction rate. Interestingly the presence of KI as an additional hole scavenger with oxalic acid had a considerable impact on the reaction mechanism and thus the hydrogen yield as indicated by the QMS and the EPR measurements. The added KI promoted H2 evolution to reach the theoretically predictable amount and inhibited the formation of intermediates without affecting the oxalic acid degradation rate. The proposed mechanism by which KI boosts the photocatalytic performance is of great importance in enhancing the overall energy efficiency for hydrogen production via photocatalytic organic reforming.
New Liquid Chemical Hydrogen Storage Technology
Aug 2022
Publication
The liquid chemical hydrogen storage technology has great potentials for high-density hydrogen storage and transportation at ambient temperature and pressure. However its commercial applications highly rely on the high-performance heterogeneous dehydrogenation catalysts owing to the dehydrogenation difficulty of chemical hydrogen storage materials. In recent years the chemists and materials scientists found that the supported metal nanoparticles (MNPs) can exhibit high catalytic activity selectivity and stability for the dehydrogenation of chemical hydrogen storage materials which will clear the way for the commercial application of liquid chemical hydrogen storage technology. This review has summarized the recent important research progress in the MNP-catalyzed liquid chemical hydrogen storage technology including formic acid dehydrogenation hydrazine hydrate dehydrogenation and ammonia borane dehydrogenation discussed the urgent challenges in the key field and pointed out the future research trends.
Estimation of the Influence of Compressed Hydrogen on the Mechanical Properties of Pipeline Steels
Sep 2021
Publication
Consideration of the possibility of transporting compressed hydrogen through existing gas pipelines leads to the need to study the regularities of the effect of hydrogen on the mechanical properties of steels in relation to the conditions of their operation in pipelines (operating pressure range stress state of the pipe metal etc.). This article provides an overview of the types of influence of hydrogen on the mechanical properties of steels including those used for the manufacture of pipelines. The effect of elastic and plastic deformations on the intensity of hydrogen saturation of steels and changes in their strength and plastic deformations is analyzed. An assessment of the potential losses of transported hydrogen through the pipeline wall as a result of diffusion has been made. The main issues that need to be solved for the development of a scientifically grounded conclusion on the possibility of using existing gas pipelines for the transportation of compressed hydrogen are outlined.
Stationary Hybrid Renewable Energy Systems for Railway Electrification: A Review
Sep 2021
Publication
This article provides an overview of modern technologies and implemented projects in the field of renewable energy systems for the electrification of railway transport. In the first part the relevance of the use of renewable energy on the railways is discussed. Various types of power-generating systems in railway stations and platforms along the track as well as in separate areas are considered. The focus is on wind and solar energy conversion systems. The second part is devoted to the analysis of various types of energy storage devices used in projects for the electrification of railway transport since the energy storage system is one of the key elements in a hybrid renewable energy system. Systems with kinetic storage electrochemical storage batteries supercapacitors hydrogen energy storage are considered. Particular attention is paid to technologies for accumulating and converting hydrogen into electrical energy as well as hybrid systems that combine several types of storage devices with different ranges of charge/discharge rates. A comparative analysis of various hybrid electric power plant configurations depending on the functions they perform in the electrification systems of railway transport has been carried out.
Hydrogen Energy: a New Dimension for the Energy Cooperation in the Northeast Asian Region
Nov 2020
Publication
The Northeast Asian Region is a home for the major world’s energy importers and Russia – the top energy exporter. Due to the depletion of national fossil energy resources the industrialised East Asian economies are facing serious energy security issues. The snapshot of the intraregional energy trade in 2019 was analysed in terms of development potential. Japan Korea and China are at the frontline of hydrogen energy technologies commercialisation and hydrogen energy infrastructure development. The drivers for such endeavours are listed and national institutions for hydrogen energy development are characterised. The priorities related to regional cooperation on hydrogen energy in Northeast Asia were derived on the basis of hydrogen production cost estimations. These priorities include steady development of international natural gas and power infrastructure. The shared process will lead to the synergy of regional fossil and renewable resources within combined power and hydrogen infrastructure.
Flare Gas Monetization and Greener Hydrogen Production via Combination with Crypto Currency Mining and Carbon Dioxide Capture
Jan 2022
Publication
In view of the continuous debates on the environmental impact of blockchain technologies in particular crypto currency mining accompanied by severe carbon dioxide emissions a technical solution has been considered assuming direct monetization of associated petroleum gas currently being flared. The proposed approach is based on the technology of low-temperature steam reforming of hydrocarbons which allows flare gas conditioning towards the requirements for fuel for gas piston and gas turbine power plants. The generation of electricity directly at the oil field and its use for on-site crypto currency mining transforms the process of wasteful flaring of valuable hydrocarbons into an economically attractive integrated processing of natural resources. The process is not carbon neutral and is not intended to compete zero-emission technologies but its combination with technologies for carbon dioxide capture and re-injection into the oil reservoir can both enhance the oil recovery and reduce carbon dioxide emissions into the atmosphere. The produced gas can be used for local transport needs while the generated heat and electricity can be utilized for on-site food production and biological carbon dioxide capture in vertical greenhouse farms. The suggested approach allows significant decrease in the carbon dioxide emissions at oil fields and although it may seem paradoxically on-site cryptocurrency mining actually may lead to a decrease in the carbon footprint. The amount of captured CO2 could be transformed into CO2 emission quotas which can be spent for the production of virtually “blue” hydrogen by steam reforming of natural gas in locations where the CO2 capture is technically impossible and/or unprofitable.
The Role of Hydrocarbons in the Global Energy Agenda: The Focus on Liquefied Natural Gas
May 2020
Publication
Presently there is a paradoxical situation in the global energy market related to a gap between the image of hydrocarbon resources (HCR) and their real value for the economy. On the one hand we face an increase in expected HCR production and consumption volumes both in the short and long term. On the other hand we see the formation of the image of HCR and associated technologies as an unacceptable option without enough attention to the differences in fuels and the ways of their usage. Due to this it seems necessary to take a step back to review the vitality of such a political line. This article highlights an alternative point of view with regard to energy development prospects. The purpose of this article is to analyse the consistency of criticism towards HCR based on exploration of scientific literature analytical documents of international corporations and energy companies as well as critical assessment of technologies offered for the HCR substitution. The analysis showed that: (1) it is impossible to substitute the majority of HCR with alternative power resources in the near term (2) it is essential that the criticism of energy companies with regard to their responsibility for climate change should lead not to destruction of the industry but to the search of sustainable means for its development (3) the strategic benchmarks of oil and coal industries should shift towards chemical production but their significance should not be downgraded for the energy sector (4) liquified natural gas (LNG) is an independent industry with the highest expansion potential in global markets in the coming years as compared to alternative energy options and (5) Russia possesses a huge potential for the development of the gas industry and particularly LNG that will be unlocked if timely measures on higher efficiency of the state regulation system are implemented.
Selected Aspects of Hydrogen Production via Catalytic Decomposition of Hydrocarbons
Feb 2021
Publication
Owing to the high hydrogen content hydrocarbons are considered as an alternative source for hydrogen energy purposes. Complete decomposition of hydrocarbons results in the formation of gaseous hydrogen and solid carbonaceous by-product. The process is complicated by the methane formation reaction when the released hydrogen interacts with the formed carbon deposits. The present study is focused on the effects of the reaction mixture composition. Variations in the inlet hydrogen and methane concentrations were found to influence the carbon product’s morphology and the hydrogen production efficiency. The catalyst containing NiO (82 wt%) CuO (13 wt%) and Al2O3 (5 wt%) was prepared via a mechanochemical activating procedure. Kinetics of the catalytic process of hydrocarbons decomposition was studied using a reactor equipped with McBain balances. The effects of the process parameters were explored in a tubular quartz reactor with chromatographic analysis of the outlet gaseous products. In the latter case the catalyst was loaded piecemeal. The texture and morphology of the produced carbon deposits were investigated by nitrogen adsorption and electron microscopy techniques.
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