Institution of Gas Engineers & Managers
Comparison of Two Energy Management Strategies Considering Power System Durability for PEMFC-LIB Hybrid Logistics Vehicle
Jun 2021
Publication
For commercial applications the durability and economy of the fuel cell hybrid system have become obstacles to be overcome which are not only affected by the performance of core materials and components but also closely related to the energy management strategy (EMS). This paper takes the 7.9 t fuel cell logistics vehicle as the research object and designed the EMS from two levels of qualitative and quantitative analysis which are the composite fuzzy control strategy optimized by genetic algorithm and Pontryagin’s minimum principle (PMP) optimized by objective function respectively. The cost function was constructed and used as the optimization objective to prolong the life of the power system as much as possible on the premise of ensuring the fuel economy. The results indicate that the optimized PMP showed a comprehensive optimal performance the hydrogen consumption was 3.481 kg/100 km and the cost was 13.042 $/h. The major contribution lies in that this paper presents a method to evaluate the effect of different strategies on vehicle performance including fuel economy and durability of the fuel cell and battery. The comparison between the two totally different strategies helps to find a better and effective solution to reduce the lifetime cost.
Effects of the Injector Direction on the Temperature Distribution During Filling of Hydrogen Tanks
Sep 2017
Publication
The development of the temperature field in hydrogen tanks during the filling process has been investigated with Computational Fluid Dynamics (CFD). Measurements from experiments undertaken at the JRC GasTef facility have been used to develop and validate the CFD modelling strategy; by means of the CFD calculations the effect of the injector direction on the temperature distribution has been analysed. It has been found that the dynamics of the temperature field including the development of potentially detrimental phenomena like thermal stratification and temperature inhomogeneity e.g. hot spots can be significantly affected by the injector orientation.
Optimal Development of Alternative Fuel Station Networks Considering Node Capacity Restrictions
Jan 2020
Publication
A potential solution to reduce greenhouse gas (GHG) emissions in the transport sector is the use of alternative fuel vehicles (AFV). As global GHG emission standards have been in place for passenger cars for several years infrastructure modelling for new AFV is an established topic. However as the regulatory focus shifts towards heavy-duty vehicles (HDV) the market diffusion of AFV-HDV will increase as will planning the relevant AFV infrastructure for HDV. Existing modelling approaches need to be adapted because the energy demand per individual refill increases significantly for HDV and there are regulatory as well as technical limitations for alternative fuel station (AFS) capacities at the same time. While the current research takes capacity restrictions for single stations into account capacity limits for locations (i.e. nodes) – the places where refuelling stations are built such as highway entries exits or intersections – are not yet considered. We extend existing models in this respect and introduce an optimal development for AFS considering (station) location capacity restrictions. The proposed method is applied to a case study of a potential fuel cell heavy-duty vehicle AFS network. We find that the location capacity limit has a major impact on the number of stations required station utilization and station portfolio variety.
Development of a Realistic Hydrogen Flammable Atmosphere Inside a 4-m3 Enclosure
Sep 2017
Publication
To define a strategy of mitigation for containerized hydrogen systems (fuel cells for example) against explosion the main characteristics of flammable atmosphere (size concentration turbulence…) shall be well-known. This article presents an experimental study on accidental hydrogen releases and dispersion into an enclosure of 4 m3 (2 m x 2 m x 1 m). Different release points are studied: two circular releases of 1 and 3 mm and a system to create ring-shaped releases. The releases are operated with a pressure between 10 and 40 bars in order to be close to the process conditions. Different positions of the release inside the enclosure i.e. centred on the floor or along a wall are also studied. A specific effort is made to characterize the turbulence in the enclosure during the releases. The objectives of the experimental study are to understand and quantify the mechanisms of formation of the explosive atmosphere taking into account the geometry and position of the release point and the confinement. Those experimental data are analyzed and compared with existing models and could bring some new elements to improve them.
Model of 3D Conjugate Heat Transfer and Mechanism of Compressed Gas Storage Failure in a Fire
Sep 2017
Publication
The 3D model of conjugate heat transfer from a fire to compressed gas storage cylinder is described. The model predictions of temperature outside and inside the cylinder as well as pressure increase during a fire are compared against a fire test experiment. The simulation reproduced measured in test temperatures and pressures. The original failure criterion of the cylinder in a fire has been applied in the model. This allowed for the prediction of the cylinder catastrophic rupture time with acceptable engineering accuracy. The significance of 3D modelling is demonstrated and recommendations to improve safety of high-pressure composite tanks are given.
Fire Tests Carried Out in FCH JU FIRECOMP Project, Recommendations and Application to Safety of Gas Storage Systems
Sep 2017
Publication
In the event of a fire composite pressure vessels behave very differently from metallic ones: the material is degraded potentially leading to a burst without significant pressure increase. Hence such objects are when necessary protected from fire by using thermally-activated devices (TPRD) and standards require testing cylinder and TPRD together. The pre-normative research project FireComp aimed at understanding better the conditions which may lead to burst through testing and simulation and proposed an alternative way of assessing the fire performance of composite cylinders. This approach is currently used by Air Liquide for the safety of composite bundles carrying large amounts of hydrogen gas.
Clean Energy and Fuel Storage
Aug 2019
Publication
Clean energy and fuel storage is often required for both stationary and automotive applications. Some of the clean energy and fuel storage technologies currently under extensive research and development are hydrogen storage direct electric storage mechanical energy storage solar-thermal energy storage electrochemical (batteries and supercapacitors) and thermochemical storage. The gravimetric and volumetric storage capacity energy storage density power output operating temperature and pressure cycle life recyclability and cost of clean energy or fuel storage are some of the factors that govern efficient energy and fuel storage technologies for potential deployment in energy harvesting (solar and wind farms) stations and on-board vehicular transportation. This Special Issue thus serves the need to promote exploratory research and development on clean energy and fuel storage technologies while addressing their challenges to a practical and sustainable infrastructure.
Conceptual Design of Pyrolytic Oil Upgrading Process Enhanced by Membrane-Integrated Hydrogen Production System
May 2019
Publication
Hydrotreatment is an efficient method for pyrolytic oil upgrading; however the trade-off between the operational cost on hydrogen consumption and process profit remains the major challenge for the process designs. In this study an integrated process of steam methane reforming and pyrolytic oil hydrotreating with gas separation system was proposed conceptually. The integrated process utilized steam methane reformer to produce raw syngas without further water–gas-shifting; with the aid of a membrane unit the hydrogen concentration in the syngas was adjusted which substituted the water–gas-shift reactor and improved the performance of hydrotreater on both conversion and hydrogen consumption. A simulation framework for unit operations was developed for process designs through which the dissipated flow in the packed-bed reactor along with membrane gas separation unit were modelled and calculated in the commercial process simulator. The evaluation results showed that the proposed process could achieve 63.7% conversion with 2.0 wt% hydrogen consumption; the evaluations of economics showed that the proposed process could achieve 70% higher net profit compared to the conventional plant indicating the potentials of the integrated pyrolytic oil upgrading process.
End of Life of Fuel Cells and Hydrogen Products: From Technologies to Strategies
Feb 2019
Publication
End-of-Life (EoL) technologies and strategies are needed to support the deployment of fuel cells and hydrogen (FCH) products. This article explores current and novel EoL technologies to recover valuable materials from the stacks of proton exchange membrane fuel cells and water electrolysers alkaline water electrolysers and solid oxide fuel cells. Current EoL technologies are mainly based on hydrometallurgical and pyro-hydrometallurgical methods for the recovery of noble metals while novel methods attempt to recover additional materials through efficient safe and cost-competitive pathways. Strengths weaknesses opportunities and threats of the reviewed EoL technologies are identified under techno-economic environmental and regulatory aspects. Beyond technologies strategies for the EoL of FCH stacks are defined mainly based on the role of manufacturers and recovery centres in the short- mid- and long-term. In this regard a dual role manufacturer/recovery centre would characterise long-term scenarios within a potential context of a well-established hydrogen economy.
Simulation of the Combustion Process for a CI Hydrogen Engine in an Argon-oxygen Atmosphere
May 2018
Publication
Hydrogen combustion in a noble gas atmosphere increases the combustion chamber temperature and the high specific heat ratio of the gas increases the thermal efficiency. In this study nitrogen was replaced by argon as the intake air along with pure oxygen to supply the engine. The objectives of this study are to determine the effects of different engine parameters on combustion and to analyse the emissions from hydrogen combustion in an argon-oxygen atmosphere. This research was conducted through simulations using CONVERGE 2.2.0 software and the YANMAR engine NF19SK model was used to determine the basic parameters. Changing the injector location affects the pressure and temperature in the combustion chamber. With increasing compression ratio the pressure increases more rapidly than the temperature. However combustion at high compression ratios decreases the maximum heat release rate and increases the combustion duration. Hydrogen combustion at ambient temperatures below 1200 K follows the Arrhenius equation.
Scale-up of Milling in a 100 L Device for Processing of TiFeMn Alloy for Hydrogen Storage Applications: Procedure and characterization
Feb 2019
Publication
In this work the mechanical milling of a FeTiMn alloy for hydrogen storage purposes was performed in an industrial milling device. The TiFe hydride is interesting from the technological standpoint because of the abundance and the low cost of its constituent elements Ti and Fe as well as its high volumetric hydrogen capacity. However TiFe is difficult to activate usually requiring a thermal treatment above 400 °C. A TiFeMn alloy milled for just 10 min in a 100 L industrial milling device showed excellent hydrogen storage properties without any thermal treatment. The as-milled TiFeMn alloy did not need any activation procedure and showed fast kinetic behavior and good cycling stability. Microstructural and morphological characterization of the as-received and as-milled TiFeMn alloys revealed that the material presents reduced particle and crystallite sizes even after such short time of milling. The refined microstructure of the as-milled TiFeMn is deemed to account for the improved hydrogen absorption-desorption properties.
A Comparison Study into Low Leak Rate Buoyant Gas Dispersion in a Small Fuel Cell Enclosure Using Plain and Louvre Vent Passive Ventilation Schemes
Sep 2017
Publication
The development of a ‘Hydrogen Economy’ will see hydrogen fuel cells used in transportation and the generation of power for buildings as part of a decentralised grid with low power units used in domestic and commercial environmental situations. Low power fuel cells will be housed in small protective enclosures which must be ventilated to prevent a build-up of hydrogen gas produced during normal fuel cell operation or a supply pipework leak. Hydrogen’s flammable range (4-75%) is a significant safety concern. With poor enclosure ventilation a low-level leak (below 10 lpm) could quickly create a flammable mixture with potential for an explosion. Mechanical ventilation is effective at managing enclosure hydrogen concentrations but drains fuel cell power and is vulnerable to failure. In many applications (e.g. low power and remote installation) this is undesirable and reliable passive ventilation systems are preferred. Passive ventilation depends upon buoyancy driven flow with the size and shape of ventilation openings critical for producing predictable flows and maintaining low buoyant gas concentrations. Environmentally installed units use louvre vents to protect the fuel cell but the performance of these vents compared to plain vertical vents is not clear. Comparison small enclosure tests of ‘same opening area’ louvre and plain vents with leak rates from 1 to 10 lpm were conducted. A displacement ventilation arrangement was installed on the test enclosure with upper and lower opposing openings. Helium gas was released from a 4mm nozzle at the base of the enclosure to simulate a hydrogen leak. The tests determined that louvre vents increased average enclosure hydrogen concentrations by approximately 10% across the leak range tested but regulated the flow. The test data was used in a SolidWorks CFD simulation model validation exercise. The model provided a good qualitative representation of the flow behaviour but under predicted average concentrations.
Application of Hydrides in Hydrogen Storage and Compression: Achievements, Outlook and Perspectives
Feb 2019
Publication
José Bellosta von Colbe,
Jose-Ramón Ares,
Jussara Barale,
Marcello Baricco,
Craig Buckley,
Giovanni Capurso,
Noris Gallandat,
David M. Grant,
Matylda N. Guzik,
Isaac Jacob,
Emil H. Jensen,
Julian Jepsen,
Thomas Klassen,
Mykhaylo V. Lototskyy,
Kandavel Manickam,
Amelia Montone,
Julian Puszkiel,
Martin Dornheim,
Sabrina Sartori,
Drew Sheppard,
Alastair D. Stuart,
Gavin Walker,
Colin Webb,
Heena Yang,
Volodymyr A. Yartys,
Andreas Züttel and
Torben R. Jensen
Metal hydrides are known as a potential efficient low-risk option for high-density hydrogen storage since the late 1970s. In this paper the present status and the future perspectives of the use of metal hydrides for hydrogen storage are discussed. Since the early 1990s interstitial metal hydrides are known as base materials for Ni – metal hydride rechargeable batteries. For hydrogen storage metal hydride systems have been developed in the 2010s [1] for use in emergency or backup power units i. e. for stationary applications.<br/>With the development and completion of the first submarines of the U212 A series by HDW (now Thyssen Krupp Marine Systems) in 2003 and its export class U214 in 2004 the use of metal hydrides for hydrogen storage in mobile applications has been established with new application fields coming into focus.<br/>In the last decades a huge number of new intermetallic and partially covalent hydrogen absorbing compounds has been identified and partly more partly less extensively characterized.<br/>In addition based on the thermodynamic properties of metal hydrides this class of materials gives the opportunity to develop a new hydrogen compression technology. They allow the direct conversion from thermal energy into the compression of hydrogen gas without the need of any moving parts. Such compressors have been developed and are nowadays commercially available for pressures up to 200 bar. Metal hydride based compressors for higher pressures are under development. Moreover storage systems consisting of the combination of metal hydrides and high-pressure vessels have been proposed as a realistic solution for on-board hydrogen storage on fuel cell vehicles.<br/>In the frame of the “Hydrogen Storage Systems for Mobile and Stationary Applications” Group in the International Energy Agency (IEA) Hydrogen Task 32 “Hydrogen-based energy storage” different compounds have been and will be scaled-up in the near future and tested in the range of 500 g to several hundred kg for use in hydrogen storage applications.
Analysis of Out-of-spec Events During Refueling of On-board Hydrogen Tanks
Sep 2017
Publication
For refuelling on-board hydrogen tanks table-based or formula based protocols are commonly used. These protocols are designed to achieve a tank filling close to 100% SOC (State of Charge) in s safe way: without surpassing temperature (-40°C to 85°C) and pressure limits (125% Nominal Working Pressure NWP). The ambient temperature the initial pressure and the volume category of the (compressed hydrogen storage system CHSS are used as inputs to determine the final target pressure and the pressure ramp rate (which controls the filling duration). However abnormal out-of-spec events (e.g. misinformation of storage system status and characteristics of the storage tanks) may occur and result in a refuelling in which the safety boundaries are surpassed. In the present article the possible out of specification (out-of-spec) events in a refuelling station have been analyzed. The associated hazards when refuelling on-board hydrogen tanks have been studied. Experimental results of out-of-spec event tests performed on a type 3 tank are presented. The results show that on the type 3 tank the safety temperature limit of 85°C was only surpassed under a combination of events; e.g. an unnoticed stop of the cooling of the gas combined with a wrong input of ambient temperature at a very warm environment. On the other hand under certain events (e.g. cooling the gas below the target temperature) and in particular under cold environmental conditions the 100% SOC limit established in the fuelling protocols has been surpassed. Hydrogen safety on-board tanks refuelling protocols out-of-spec events.
Health and safety in the new energy economy
Dec 2010
Publication
Over the next decade and beyond the UK is set to take significant steps towards a new energy economy. This will be an economy where the technologies meeting<br/>our electricity heat and fuel needs have to deliver against three key criteria: sustainability security and affordability.<br/><br/>In this context a wide range of emerging energy technologies are expected to play an important role in reshaping the way we satisfy our energy requirements. The extent to which they do so however will depend fundamentally on their ability to be harnessed safely.<br/><br/>Compiled by HSE’s Emerging Energy Technologies Programme this report provides a current assessment of the health and safety hazards that key emerging energy technologies could pose both to workers and to the public at large. (Nuclear energy technologies fall outside the scope of this report.) But it also highlights how an appropriate framework can be and is being put in place to help ensure that these hazards are managed and controlled effectively – an essential<br/>element in enabling the technologies to make a major contribution to the UK’s energy future.
A Comparative CFD Assessment Study of Cryogenic Hydrogen and Liquid Natural Gas Dispersion
Sep 2017
Publication
The introduction of hydrogen to the commercial market as alternative fuel brings up safety concerns. Its storage in liquid or cryo-compressed state to achieve volumetric efficiency involves additional risks and their study is crucial. This work aims to investigate the behaviour of cryogenic hydrogen release and to study factors that affect the vapor dispersion. We focus on the effect of ambient humidity and air's components (nitrogen and oxygen) freezing in order to identify the conditions under which these factors have considerable influence. The study reveals that the level of influence depends highly on the release conditions and that humidity can reduce conspicuously the longitudinal distance of the Lower Flammability Limit (LFL). Low Froude (Fr) number (<1000) at the release allows the generated by the humidity phase change buoyancy to affect the dispersion while for higher Fr number - that usually are met in cryo-compressed releases - the momentum forces are the dominant forces and the buoyancy effect is trivial. Simulations with liquid methane release have been also performed and compared to the liquid hydrogen simulations in order to detect the differences in the behaviour of the two fuels as far as the humidity effect is concerned. It is shown that in methane spills the buoyancy effect in presence of humidity is smaller than in hydrogen spills and it can be considered almost negligible.
Highly Resolve Large Eddy Simulations of a Transitional Air-helium Buoyant Jet in a Two Vented Enclosure: Validation Against Particle Image Velocimetry Experiments
Sep 2017
Publication
The article deals with LES simulations of an air-helium buoyant jet in a two vented enclosure and their validation against particle image velocimetry experiments. The main objective is to test the ability of LES models to simulate such scenarios. These types of scenarios are of first interest considering safety studies for new hydrogen systems. Three main challenges are identified. The two first are the ability of the LES model to account for a rapid laminar-to-turbulence transition mainly due to the buoyancy accelerations and the Rayleigh-Taylor instabilities that can develop due to sharp density gradients. The third one is the outlet boundary conditions to be imposed on the vent surfaces. The influence of the classical pressure boundary condition is studied by comparing the simulations results when an exterior region is added in the simulations. The comparisons against particle image velocimetry experiments show that the use of an exterior domain gives more accurate results than the classical pressure boundary condition. This result and the description of the phenomena involved are the main outlets of the article.
Compact Heat Integrated Reactor System of Steam Reformer, Shift Reactor and Combustor for Hydrogen Production from Ethanol
Jun 2020
Publication
A compact heat integrated reactor system (CHIRS) of a steam reformer a water gas shift reactor and a combustor were designed for stationary hydrogen production from ethanol. Different reactor integration concepts were firstly studied using Aspen Plus. The sequential steam reformer and shift reactor (SRSR) was considered as a conventional system. The efficiency of the SRSR could be improved by more than 12% by splitting water addition to the shift reactor (SRSR-WS). Two compact heat integrated reactor systems (CHIRS) were proposed and simulated by using COMSOL Multiphysics software. Although the overall efficiency of the CHIRS was quite a bit lower than the SRSR-WS the compact systems were properly designed for portable use. CHIRS (I) design combining the reactors in a radial direction was large in reactor volume and provided poor temperature control. As a result the ethanol steam reforming and water gas shift reactions were suppressed leading to lower hydrogen selectivity. On the other hand CHIRS (II) design combining the process in a vertical direction provided better temperature control. The reactions performed efficiently resulting in higher hydrogen selectivity. Therefore the high performance CHIRS (II) design is recommended as a suitable stationary system for hydrogen production from ethanol.
Hydrogen - A Pipeline to the Future
Sep 2020
Publication
Scotland’s Achievements and Ambitions for Clean Hydrogen - a joint webinar between the Scottish Hydrogen and Fuel Cell Association and the Pipeline Industries Guild (Scottish branch).
Nigel Holmes. CEO Scottish Hydrogen & Fuel Cell Association provides an update on Scotland’s ambitions backed up by progress in key areas. This will show the potential for hydrogen at scale to support the delivery of policy targets highlighting areas of key strengths for Scotland.
You will also hear about the need to build up scale for hydrogen production and supply in tandem with hydrogen pipeline and distribution networks in order to meet demand for low carbon energy and achieve key milestones on the pathway to Net Zero by 2045.
Nigel Holmes. CEO Scottish Hydrogen & Fuel Cell Association provides an update on Scotland’s ambitions backed up by progress in key areas. This will show the potential for hydrogen at scale to support the delivery of policy targets highlighting areas of key strengths for Scotland.
You will also hear about the need to build up scale for hydrogen production and supply in tandem with hydrogen pipeline and distribution networks in order to meet demand for low carbon energy and achieve key milestones on the pathway to Net Zero by 2045.
Isotopic Tracing of Hydrogen Transport and Trapping in Nuclear Materials
Jun 2017
Publication
Some illustrations of the use of deuterium or tritium for isotopic tracing of hydrogen absorption transport and trapping in nuclear materials are presented. Isotopic tracing of hydrogen has been shown to be successful for the determination of the boundaries conditions for hydrogen desorption or absorption in a material exposed to a hydrogen source. Also the unique capabilities of isotopic tracing and related techniques to characterize H interactions with point defects and dislocations acting as moving traps has been demonstrated. Such transport mechanisms are considered to play a major role in some stress corrosion cracking and hydrogen embrittlement mechanisms.
Link to document download on Royal Society Website
Link to document download on Royal Society Website
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