Hydrogen Storage Unit Research Articles

Integration of large-scale hydrogen storages in a low-carbon electricity generation system

This study investigates the overall feasibility of large energy storages with hydrogen as energy carrier onsite with a pre-combustion carbon capture and storage coal gasification plant and assesses the general impacts of such a backup installation on an electricity generation system with high wind power portion. The developed system plant configuration consists of four main units namely the gasification unit, main power unit, backup power unit including hydrogen storage and ancillary power unit. Findings show that integrating a backup storage in solid or gaseous hydrogen storage configuration allows to store excessive energy under high renewable power output or low demand and to make use of the stored energy to compensate low renewable output or high power demand. The study concludes that the developed system configuration reaches much higher load factors and efficiency levels than a plant configuration without backup storage, which simply increases its power unit capacity to meet the electricity demand. Also from an economical point of view, the suggested system configurations are capable to achieve lower electricity generation costs.

Ni-Cd Batteries as Hydrogen Storage Units of High-Capacity

0.3-0.5. Analysis of the gas released from both electrodes showed that it consisted of at least 99% hydrogen.

Bio-inspired chemical hydrogen storage and discharge as a source of electrical energy

Reversible bio-inspired chemical hydrogen storage systems accumulate electrical energy in the form of electrons and proton ions located on biomolecules or bio-like storage molecules. Electro-active biomolecules (EAB) in Yeast media show such behavior: 2e− + 2H+ + EAB (aq) + ⇆ EABH/H (aq) + , also electro-active Methylene Blue (MB): 2e− + 2H+ + MB (aq) + ⇆ MBH/H (aq) + . The power characteristics of microbial fuel cell stacks equipped with such bio-inspired hydrogen storage systems were examined. E. coli cultures charged these bio-inspired separate chemical hydrogen storage units up to E = 0.50 ± 0.06 V; cell potentials increased proportionally in serial double, triple, and quadruple hydrogen storage stacks up to E OCV = 1.98 V; the maximum power densities that were obtained improved proportionally with stack length by an increment of 1.4. The bio-inspired chemical hydrogen storage principle is of great interest for application in low-cost batteries that store renewable energy.

Finite element model for charge and discharge cycle of activated carbon hydrogen storage

One of the main challenges to introduce hydrogen on the energy market is to improve on-board hydrogen storage and develop more efficient distribution technologies to increase the amount of stored gas while lowering the storage pressure. The physisorption of hydrogen on activated carbons (AC) is being investigated as a possible route for hydrogen storage. The objective of this work is to study the performance of adsorption-based hydrogen storage units from a "systems" point of view. A realistic two-dimensional axisymmetric geometric model which couples mass, momentum and energy balances is established based on the thermodynamic conservation laws using finite element method as implemented in COMSOL Multiphysics™. We consider the charging and discharging of the storage unit at a rated pressure of 9 MPa, and at an initial temperature of 302 K. The results are compared with experimental data obtained at the Hydrogen Research Institute of the University of Quebec at Trois-Rivieres. The storage tank is cooled by ice water. Research results show that both the simulated variations of pressure and temperatures during charge and discharge processes are in good agreement with the experimental data. The temperatures in the central region of tank are higher than those at the entrance and near the wall at the end of charge time while they are lower than those at the entrance and near the wall at the end of discharge time. The velocities are largest at the entrance, and decrease gradually along the axis of the tank. Owing to thermal effects, the larger flow rates result in less amount of adsorption in the condition of the same charging pressure. Hence measures of increasing heat transfer should be adopted, such as increasing the thermal conductivity of the storage bed. From the point of view of storage capacity, it is therefore possible to realize rapid hydrogenation, which is conducive to the use of such systems for on-board hydrogen storage based on activated carbon adsorption.

Design and optimization of hydrogen storage units using advanced solid materials: General mathematical framework and recent developments

This review presents the general mathematical framework of modeling, design and optimization of hydrogen storage using advanced solid materials. The emphasis is given on metal hydride storage tanks, since these systems have been well studied in the literature, both theoretically and experimentally, and are expected to offer significant advantages when current research and development efforts succeed in commercializing the required technology. Enhanced cooling during hydrogen filling of the storage tank is found to be essential to improve hydrogen storage time requirements. For this reason several innovative design strategies for heat exchanger configurations are presented and evaluated in terms of process design and performance improvement. Finally, control and optimization of certain operating conditions can also have a significant impact in hydrogen storage operation.

Partial substitution of hydrogen for conventional fuel in an aircraft by utilizing unused cargo compartment space

Options are being actively sought in aviation to switch from petroleum-based fuels to alternative fuels, of which hydrogen is a promising candidate, despite challenges associated with its production and storage. The possibility is demonstrated in this study of using hydrogen in place of some mission fuel without making substantial aircraft modifications and while utilizing only available unused baggage space in the lower-deck cargo compartments of aircraft. The environmental impact reduction and weight increase are obtained accounting for a broad range of factors including aircraft model, seat capacity, passenger and baggage load factors, annual landing and take off cycles, container type, and costs of metal hydride and gaseous hydrogen storage units of various sizes. It is found that, while there may be a cost increase, CO 2 emissions are substantially reduced, by 25,000–570,000 tonnes annually in several cases and by up to 1.1 million tonnes annually for the 10 types of aircraft considered. It is also determined that with present technology, despite the low density of hydrogen, the weight of storage systems constitutes more of a challenge than their volume in aviation. Large-body aircraft are found to have more difficulties than the narrow-body aircraft regarding storage system weight. For the most frequently used narrow- and large-body aircraft considered, the number of the available containers within the required limits of weight and volume respectively are found to be 3 and 4 for the B 737-800 aircraft and 2 and 10 for the A 340-300 aircraft. Overall, the combined usage of hydrogen and kerosene investigated here may be feasible in the future, but is a challenging option with present technology and aircraft due to various factors.

Integrating hydrogen generation and storage in a novel compact electrochemical system based on metal hydrides

The development of efficient and reliable energy storage systems based on hydrogen technology represents a challenge to seasonal storage based on renewable hydrogen. State of the art renewable energy generation systems include separate units such as electrolyzer, hydrogen storage vessel and a fuel cell system for the conversion of H 2 back into electricity, when required. In this work, a novel electrochemical system has been developed which integrates hydrogen production, storage and compression in only one device, at relatively low cost and high efficiency. The developed prototype comprises a six-electrode cell assembly using an AB 5-type metal hydride and Ni plates as counter electrodes, in a 35-wt% KOH solution. Metal hydride electrodes with chemical composition LaNi 4.3Co 0.4Al 0.3 were prepared by high frequency vacuum melting followed by high temperature annealing. X-ray phase analysis showed typical hexagonal structure and no traces of other intermetallic compounds belonging to the La–Ni phase diagram. Thermodynamic study has been performed in a Sieverts type of apparatus produced by Labtech Int. During cycling, the charging/discharging process was studied in situ using a gas chromatograph from Agilent. It is anticipated that the device will be integrated as a combined hydrogen generator and storage unit in a stand-alone system associated to a 1-kW fuel cell.

Development and simulation of a hydrogen storage unit using metal hydrides

This paper presents a hydrogen storage system using metal hydrides for a Combined Heat and Power CHP) system. Hydride storage technology has been chosen due to project specifications: high volumetric capacity, low pressures (<3.5 bar) and low temperatures (<75 °C: fuel cell temperature). During absorption, heat from hydride generation is dissipated by fluid circulation. An integrated plate-fin type heat exchanger has been designed to obtain good compacity and to reach high absorption/desorption rates. At first, the storage system has been tested in accordance with project specifications (absorption/desorption 3.5/1.5 bar). Then, the hydrogen charge/discharge times have been decreased to reach system limits. System design has been used to simulate thermal and mass comportment of the storage tank. The model is based on the software Fluent. We take in consideration heat and mass transfers in the porous media and a convective flow for cooling/heating the system during absorptions/desorptions. The hydride thermal and mass comportment has been integrated in the software. The heat and mass transfers experimentally obtained have been compared to results calculated by the model.

Influence of intrinsic hydrogenation/dehydrogenation kinetics on the dynamic behaviour of metal hydrides: A semi-empirical model and its verification

Metal hydrides can store hydrogen at low pressures and with high volumetric capacity. For the possible application as storage medium in hydrogen stand-alone power systems, large metal hydride hydrogen storage units are usually required. A reliable and verified kinetic correlation is an important tool in the designing process of a larger storage unit. This paper describes kinetic investigation of a AB 5-type alloy and its corresponding hydride, with the purpose of finding a semi-empirical correlation suitable for use in heat and mass transfer modelling and engineering design of metal hydride storage units.

In situ SR-XRD studies of hydrogen absorption–desorption in LaNi 4.7Sn 0.3

Phase-structural transformations during hydride formation and decomposition in the advanced hydrogen storage alloy LaNi 4.7Sn 0.3, are studied by in situ synchrotron X-ray powder diffraction (SR-XRD). A specially designed cell for in situ studies in H 2-atmosphere is attached to a metal hydride hydrogen storage unit developed at IFE providing hydrogen gas at convenient pressures. The studied sample is kept in a quartz glass capillary. Temperature cycling between RT and 100 ° C at H 2 pressures of 2–3 bar was employed to LaNi 4.70Sn 0.30H°∼6 which resulted in a reversible hydrogen absorption–desorption process. Both a large temperature-dependent homogeneity range of the β -hydride and a small hysteresis in the formation-decomposition of the β -hydride have been revealed.

Simulation and operational assessment for a small autonomous wind–hydrogen energy system

A case study with respect to the current trends in hydrogen technology and market developments is presented in this paper. The main goal is to design an autonomous, environmentally sustainable and zero emission power system using commercially available equipment. In order to achieve the optimum cost effective solution, its limitations are defined by simulating its performance over a year. A scenario is chosen which is representative of an area with significant wind potential, where the grid connection is relatively long or the construction of the line itself would irretrievably harm the environment. This study simulated the operation of a small, remote hotel primarily powered by a wind turbine and supported by a hydrogen energy system incorporating a medium pressure electrolyzer, a compressed hydrogen gas storage unit and a PEM fuel cell stack. The simulated load is biased towards a particular season as in the case of a small hotel for summer holidays. This arrangement takes advantage of the long period of low load during the “off peak” season, which enables the production of reserves of hydrogen to supplement the wind generated electricity during the “peak” season, avoiding the use of a large electrolyzer system, which is the most expensive and vulnerable component. The simulation results showed that for this particular system, a wind turbine rated at four times the peak load power associated with the optimum combination of an electrolyzer and a hydrogen storage unit would meet the electrical energy needs of a 10 bedroom, non-luxury hotel under the supervision of a load management controller.

Optimisation of [formula omitted] ( [formula omitted], Ce, Nd and Pr, [formula omitted]) compositions as hydrogen storage materials

In the frame of the development of a hydrogen production and storage unit to supply a 40 kW stationary fuel cell, a metal hydride storage tank was chosen according to its reliability and high energetic efficiency. For this purpose, the AB 5-type system MmNi 5 - x Sn x (Mm stands for mischmetal) has been investigated. Hydrogen absorption and desorption plateau pressures were adapted to the working range by adjusting the tin content. The structural and thermodynamic properties of the metal hydrides have been analyzed. Stoichiometry ( B / A ratio) and composition have been adjusted to obtain single phase compounds with maximum hydrogenation capacity. Reversible storage capacity was optimized by lanthanum enrichment of the mischmetal. Finally, a study of the kinetics and of the defects created during cycling was made.

A hybrid power generation system: solar-driven Rankine engine-hydrogen storage

This paper reports on the feasibility of a hybrid power generation system consisting of a solar energy-driven Rankine engine and a hydrogen storage unit. Solar energy, the power for the hybrid system, is converted into electrical power through a combination of a solar collector, a tracking device to maintain proper orientation with the sun and a Rankine cycle engine driving an electrical power generator. Excess electricity is utilized to produce hydrogen for storage through electrolysis of water. At the solar down time, the stored hydrogen can be used to produce high-quality steam in an aphodid burner to operate a turbine and with a eld modulated generator to supplement electric power. Case studies are carried out on the optimum conguration of the hybrid system satisfying the energy demand. A numerical example based on the actual measured solar input is also included to demonstrate the design potential. Copyright 2001 John Wiley & Sons, Ltd.

A hybrid power generation system: solar‐driven Rankine engine–hydrogen storage

This paper reports on the feasibility of a hybrid power generation system consisting of a solar energy-driven Rankine engine and a hydrogen storage unit. Solar energy, the power for the hybrid system, is converted into electrical power through a combination of a solar collector, a tracking device to maintain proper orientation with the sun and a Rankine cycle engine driving an electrical power generator. Excess electricity is utilized to produce hydrogen for storage through electrolysis of water. At the solar down time, the stored hydrogen can be used to produce high-quality steam in an aphodid burner to operate a turbine and with a field modulated generator to supplement electric power. Case studies are carried out on the optimum configuration of the hybrid system satisfying the energy demand. A numerical example based on the actual measured solar input is also included to demonstrate the design potential. Copyright © 2001 John Wiley & Sons, Ltd.

An assessment of the likelihood of occurrence, and the damage potential of domino effect (chain of accidents) in a typical cluster of industries

Abstract In the context of risk assessment and loss prevention in chemical process industries, the term domino effect denotes ‘chain of accidents’, or situations when a fire/explosion/missile/toxic load generated by an accident in one unit in an industry causes secondary and higher order accidents in other units. Most of the past risk assessment studies deal with accident in a single industry, more so in one of the units of an industry. But, often, accident in one unit can cause a secondary accident in a nearby unit, which in turn may trigger a tertiary accident, and so on. The probability of occurrence and adverse impacts of such ‘domino’ or ‘cascading’ effects are increasing due to increasing congestion in industrial complexes and increasing density of human population around such complexes. The multi-accident catastrophe which occurred in a refinery at Vishakhapatnam, India, on 14 September 1997, claiming 60 lives and causing loss of property worth over Rs 600 million, is the most recent example of the damage potential of domino effect [Lees F.P. Loss prevention in process industries, 2nd ed. Butterworths, 1-3, London; Khan, F.I., & Abbasi, S.A. (1999a). Major accidents in process industries and an analysis of their causes and consequences. Journal of Loss Prevention in Process Industries, 12, 361–378; Khan, F.I., & Abbasi, S.A. (1999b). The worst chemical industry accident of 1990's–what happened and what might have been: A quantitative study. Process Safety Progress, 18, 135–145]. Recently, we have proposed a systematic methodology called ‘domino effect analysis’ (DEA). A computer automated tool DOMIFFECT has also been developed by us based on DEA [Khan, F.I., & Abbasi, S.A. (1998a). Models for domino effect analysis in chemical process industries. Process Safety Progress — AIChE, 17 (2), 107–113; Khan, F.I., & Abbasi, S.A. (1998b). DOMIFFECT (DOMIno eFFECT): a new software for domino effect analysis in chemical process industries. Environmental Modelling and Software, 13, 163–177.]. The methodology is based on deterministic models used in conjunction with probabilistic analysis. This paper illustrates the application of DEA and DOMIFFECT to an industrial complex. Out of 16 credible accident scenarios envisaged in four closely situated industries namely Madras Fertilisers Limited (MFL), SPIC–Heavy Chemical Division (SPIC–HCD). Manali Petrochemical Limited (MPL), and Tamilnadu Petroproducts Limited (TPL), ten scenarios forecast domino effect. Further analysis reveals that accidents in the ammonia synthesis unit, secondary reformer, and urea reactor of MFL may cause domino effect. Similarly, accidents in the storage units of propylene oxide, ethylene oxide and mono propylene glycol at MPL, hydrogen storage units at SPIC–HCD, and the propylene oxide and fuel oil storage units of TPL are likely to cause a domino effect. The consequences of all these credible accidents have also been forecast. The paper makes a strong case for making DEA an integral part of all risk assessment initiatives.

A hybrid power generation system: solar-driven Rankine engine-hydrogen storage

This paper reports on the feasibility of a hybrid power generation system consisting of a solar energy-driven Rankine engine and a hydrogen storage unit. Solar energy, the power for the hybrid system, is converted into electrical power through a combination of a solar collector, a tracking device to maintain proper orientation with the sun and a Rankine cycle engine driving an electrical power generator. Excess electricity is utilized to produce hydrogen for storage through electrolysis of water. At the solar down time, the stored hydrogen can be used to produce high-quality steam in an aphodid burner to operate a turbine and with a field modulated generator to supplement electric power. Case studies are carried out on the optimum configuration of the hybrid system satisfying the energy demand. A numerical example based on the actual measured solar input is also included to demonstrate the design potential. Copyright © 2001 John Wiley & Sons, Ltd.

Evaluation of thermodynamic parameters for hydrogen in the storage device ST-90®

The thermodynamic parameters such as partial molar enthalpy (Δ H H), partial molar entropy (Δ S H), and partial molar excess entropy (Δ S E H) of the dissolved hydrogen in the hydrogen storage unit ST-90 ® containing 18.6 kg of misch metal based AB 5 alloy are evaluated based on the calculation of Sieverts constant and from Clausius–Clapeyron equation. The partial molar enthalpy at infinite dilution (Δ H 0 H) and the partial molar excess entropy at infinite dilution (Δ S E,0 H) have been obtained from the dependence of and on the hydrogen concentration. The nature of metal-hydrogen and hydrogen interactions are also evaluated for the three single phases namely α, β and γ. The hydrogen–hydrogen interaction is attractive in the α phase and repulsive in the β and γ phases. For the mixed phases α+ β and β+ γ, it is very difficult to predict the nature of the interactions either as attractive or repulsive.

Hydrogen desorption studies on hydrogen storage unit ST-90® containing the alloy MnNi4.6Al0.4—identification of two hydride phases

The evidence for the formation of two different hydride phases corresponding to MmNi 4.6 Al 0.4 H 2.2 and MmNi 4.6 Al 0.4 H 4.2 in the alloy system MmNi 4.6 Al 0.4 is presented. The results are based on desorption isotherms in the temperature range 293–343K and pressures up to 25 atm, and desorption by differential heating on 16–18 kg weight of the alloy contained in the storage device ST-90®. In the course of its evaluation as a storage device coupled to a PEM fuel cell, the thermodynamic parameters ΔH and ΔS are also reported.