Development of regulations,codes and standards on composite tanks for on-board gaseous hydrogen storage

Composite tanks for on-board gaseous hydrogen storage is one of key parts of the hydrogen fuel cell vehicle. Regulations, codes and standards (RC & S) are conducive to overcoming technological barriers to commercialization. This paper reviews the development of RC & S on composite tanks for on-board gaseous hydrogen storage and addresses their highlights on technical requirements. First, an overview of RC & S for composite tanks is introduced. Then, a comparative study on technical requirements of RC & S including service conditions, design requirements, materials, manufacture, qualification tests and management is presented. Finally, several major differences in RC & S, i.e., tank classification in ISO 19881 and penetration test method are discussed. Some issues for further research, such as initial burst pressure, material hydrogen compatibility and periodic inspection methods are proposed.     

Hydrogen storage technology: Current status and prospects

储氢技术作为氢气生产与使用之间的桥梁,至关重要。本文综述了目前常用的储氢技术,主要包括物理储氢、化学储氢与其它储氢。物理储氢主要包括高压气态储氢与低温液化储氢,具有低成本、易放氢、氢气浓度高等特点,但安全性较低。化学储氢包括有机液体储氢、液氨储氢、配位氢化物储氢、无机物储氢与甲醇储氢。其虽保证了安全性,但其放氢难,且易发生副反应,氢气浓度较低。其它储氢技术包括吸附储氢与水合物法储氢。吸附储氢技术的储氢效率受吸附剂的影响较大,且不同程度的存在放氢难、成本高、储氢密度不高等问题。水合物法储氢具有易脱氢、成本低、能耗低等特点,但其储氢密度较低。在此基础上,本文基于现状分析,简要展望了储氢技术今后的研究方向。     

Current situation and prospect of hydrogen storage technology with new organic liquid

This paper starts with the brief introduction to various methods of hydrogen storage, such as pressurized gaseous hydrogen storage, cryogenic liquefaction hydrogen storage, carbonaceous materials hydrogen storage, metal alloy hydrogen storage, complexation hydride hydrogen storage, glass microspheres hydrogen storage, liquid organic hydrogen storage, and so on. The corresponding principles of hydrogen storage were summarized with the analysis on advantages and disadvantages. Additionally, the characteristics of hydrogen storage with N-ethylcarbazole were profoundly discussed. The conditions and catalysts for hydrogenation and dehydrogenation (N-ethylcarbazole) were also analyzed at some length as well. According to the present situation of hydrogen storage with organic liquids, some ideas were put forward to get higher content and speed of absorbing and releasing hydrogen.     

Large-scale storage of hydrogen

The large-scale storage of hydrogen plays a fundamental role in a potential future hydrogen economy. Although the storage of gaseous hydrogen in salt caverns already is used on a full industrial scale, the approach is not applicable in all regions due to varying geological conditions. Therefore, other storage methods are necessary. In this article, options for the large-scale storage of hydrogen are reviewed and compared based on fundamental thermodynamic and engineering aspects. The application of certain storage technologies, such as liquid hydrogen, methanol, ammonia, and dibenzyltoluene, is found to be advantageous in terms of storage density, cost of storage, and safety. The variable costs for these high-density storage technologies are largely associated with a high electricity demand for the storage process or with a high heat demand for the hydrogen release process. If hydrogen is produced via electrolysis and stored during times of low electricity prices in an industrial setting, these variable costs may be tolerable.     

Performances comparison of adsorption hydrogen storage tanks at a wide temperature and pressure zone

Large-scale application of hydrogen requires safe, reliable and efficient storage technologies. Among the existing hydrogen storage technologies, cryo-compressed hydrogen (CcH₂) storage has the advantages of high hydrogen storage density, low energy consumption and no ortho-para hydrogen conversion. But it still needs higher hydrogen storage pressure when reaching higher hydrogen storage density. In order to reduce hydrogen storage pressure and improve storage density, solid adsorption technology is introduced in CcH₂. Activated carbon and metal-organic framework materials (MOFs) are employed as adsorbents in this paper. The gravimetric/volumetric hydrogen storage capacities of different adsorption tanks are studied and compared with the hydrogen storage conditions of 1–55 MPa at 77–298 K. The results show that the hydrogen storage density of CcH₂ combined with adsorption is higher than that of pure adsorption hydrogen storage, and the storage pressure is lower than that of pure CcH₂ under the same hydrogen storage capacity. And the combination of two hydrogen storage technologies can achieve a high hydrogen storage capacity equivalent to that of liquid hydrogen at a lower pressure.     

全球加氢站产业、技术及标准进展综述

以美国、欧洲、日本、中国的加氢站作为考察对象,就产业投资运营、主要设备商、相关标准进行梳理,结果表明：在加氢站投资及运营管理方面,美国、欧洲、日本具有较为成熟的经验;在氢增压、储存、加注等技术方面,德国、日本保持领先地位。在诸多氢气和液氢的技术领域,美国保持领先地位;在一些细分技术领域,英国、法国、挪威、俄罗斯具有优势;在加氢站标准方面,美国、日本具有较为完善的标准体系。中国已解决70 MPa氢气增压、加注、储存等领域的部分技术难题,但与其他国家相比,离子液式氢压缩机、液氢泵、液氢储罐、液氢加氢枪等产品的研发仍需持续推进。     

Recent challenges of hydrogen storage technologies for fuel cell vehicles

Fuel cell vehicles have a high potential to reduce both energy consumption and carbon dioxide emissions. However, due to the low density, hydrogen gas limits the amount of hydrogen stored on board. This restriction also prevents wide penetration of fuel cells. Hydrogen storage is the key technology towards the hydrogen society. Currently high-pressure tanks and liquid hydrogen tanks are used for road tests, but both technologies do not meet all the requirements of future fuel cell vehicles. This paper briefly explains the current status of conventional technologies (simple containment) such as high-pressure tank systems and cryogenic storage. Another method, hydrogen-absorbing alloy has been long investigated but it has several difficulties for the vehicle applications such as low temperature discharge characteristics and quick charge capability due to its reaction heat. We tested a new idea of combining metal hydride and high pressure. It will solve some difficulties and improve performance such as gravimetric density. This paper describes the latest material and system development.     

Hydrogen storage – Industrial prospectives

The topic of this paper is to give an historical and technical overview of hydrogen storage vessels and to detail the specific issues and constraints of hydrogen energy uses. Hydrogen, as an industrial gas, is stored either as a compressed or as a refrigerated liquefied gas. Since the beginning of the last century, hydrogen is stored in seamless steel cylinders. At the end of the 60 s, tubes also made of seamless steels were used; specific attention was paid to hydrogen embrittlement in the 70 s. Aluminum cylinders were also used for hydrogen storage since the end of the 60 s, but their cost was higher compared to steel cylinders and smaller water capacity. To further increase the service pressure of hydrogen tanks or to slightly decrease the weight, metallic cylinders can be hoop-wrapped. Then, with specific developments for space or military applications, fully-wrapped tanks started to be developed in the 80 s. Because of their low weight, they started to be used in for portable applications: for vehicles (on-board storages of natural gas), for leisure applications (paint-ball) etc… These fully-wrapped composite tanks, named types III and IV are now developed for hydrogen energy storage; the requested pressure is very high (from 700 to 850 bar) leads to specific issues which are discussed. Each technology is described in term of materials, manufacturing technologies and approval tests. The specific issues due to very high pressure are depicted.     

Hydrogen storage technology options for fuel cell vehicles: Well-to-wheel costs, energy efficiencies, and greenhouse gas emissions

Five different hydrogen vehicle storage technologies are examined on a Well-to-Wheel basis by evaluating cost, energy efficiency, greenhouse gas (GHG) emissions, and performance. The storage systems are gaseous 350 bar hydrogen, gaseous 700 bar hydrogen, Cold Gas at 500 bar and 200 K, Cryo-Compressed Liquid Hydrogen (CcH2) at 275 bar and 30 K, and an experimental adsorbent material (MOF 177) -based storage system at 250 bar and 100 K. Each storage technology is examined with several hydrogen production options and a variety of possible hydrogen delivery methods. Other variables, including hydrogen vehicle market penetration, are also examined. The 350 bar approach is relatively cost-effective and energy-efficient, but its volumetric efficiency is too low for it to be a practical vehicle storage system for the long term. The MOF 177 system requires liquid hydrogen refueling, which adds considerable cost, energy use, and GHG emissions while having lower volumetric efficiency than the CcH2 system. The other three storage technologies represent a set of trade-offs relative to their attractiveness. Only the CcH2 system meets the critical Department of Energy (DOE) 2015 volumetric efficiency target, and none meet the DOE’s ultimate volumetric efficiency target. For these three systems to achieve a 480-km (300-mi) range, they would require a volume of at least 105-175 L in a mid-size FCV.     

Expansion of fuel and power resources by the use of non-conventional power sources

An approach is considered to the expansion of fuel and power resources through the use of an ecologically pure secondary power resource, hydrogen, the production of which should be organized in an environment-friendly manner. This requirement is satisfied by the systems using water as the main raw material and in which ash and slag wastes of steam power plants or by-products of aluminium and magnesium industry can be employed as primary power carrier. Results are presented of a study of an advanced technology of hydrogen production with the use of a basically novel device with a flexible control system—a tractor-borne hydrogen generator. Its efficiency is provided by metered feed of power carrier in the form of paste and granules, by jet mixing with raw material (water), maintenance of a given temperature, continuous disposal of the reaction products from the device and their utilization within the scope of a waste-free technology. Problems of efficient use of hydrogen in accord with the gas-diesel scheme are examined by consideration of the example of operation of the engine of a low-toxicity tractor.     

A storage tank for vehicular storage of liquid hydrogen

This article outlines a concept for a new method of fabricating cryogenic liquid hydrogen storge tanks with emphasis on the application of liquid hydrogen as an automotive fuel. It includes a recapitulation of the properties of hydrogen and gasoline for reference, a discussion of automotive fuel utilisation rates, a thermal analysis of the liquid hydrogen boil-off rate for a reference storage container and the new concept tank. In addition, an analysis of the tank concept and its method of assembly line fabrication are provided. The conclusions reached are that this fabrication concept would provide a liquid hydrogen storage tank of improved thermal performance, that the tank could be potentially less expensive to build than current technology tanks, and that the tank would be suitable for automotive containment of liquid hydrogen.     

Opportunities and data requirements for data-driven prognostics and health management in liquid hydrogen storage systems

During the past decade, Prognostics and Health Management (PHM) has become an important set of tools in various areas of industry and academic reliability engineering. PHM consists of a variety of mathematical and computational methods used to support data-driven decision-making to increase the safety, availability, and reliability of complex engineering systems. In particular, PHM can provide crucial insight into reliability and safety design improvements for developing technologies where historical performance and failure data are limited. This is the case of hydrogen fueling and storage technologies. This work presents a high-level approach for designing data-driven PHM applications for bulk liquid hydrogen (LH₂) storage systems for hydrogen fueling stations. This paper addresses core aspects of the design, development, and implementation of data-driven PHM applications that can improve the reliability assessment of hydrogen components. The analysis focuses on the relationship between data availability and diagnostic/prognostic capabilities; potential challenges; and integration schemes for current risk mitigation measures. We identify potential condition-monitoring data sources for key components in an LH₂ storage system, including storage tanks, piping, and pumps. We determine that the short-term goals for the implementation of data-driven models in PHM frameworks in hydrogen systems should focus on developing adequate data collection and analysis strategies, as well as exploring the effect on reliability, safety, and regulations for hydrogen systems.     

Electron microscope investigation on hydrogen storage materials: A review

Hydrogen energy is a highly efficient and renewable energy carrier. The rapid and sophisticated development of nanotechnologies has promoted the transition of hydrogen storage systems from gaseous/liquid to solid-state. In order to clarify the intrinsic relationship between structure and performance, and to understand the hydrogen absorption and desorption mechanism of materials, electron microscopy (EM) can effectively help us obtain a series of information such as particle size, phase and composition determination, morphology and structure of the materials at nanoscale. The most recent progress of advanced EM techniques applied in solid-state hydrogen storage materials are summarized, which should also inspire future research on energy storage related materials.     

Experimental studies on hydrogen production in plasma discharge in a liquid-phase medium flow

The paper deals with an experimental study on hydrogen production in plasma discharge induced in a flow of liquids of various chemical compositions. The two-phase flow has been created while passing a liquid medium through a hydrodynamic irradiator at high pressure. In the liquid, an ultrasonic two-phase vapor-liquid flow may occur at lower pressure due to the pressure drop and decrease in the enthalpy of the flow. Plasma discharge has been induced by the external power supply which generates electric field inside the reaction chamber. In the experiments, the reaction chambers of several sizes and shapes with different electrode placements have been investigated.Water and spirits as well as compound ethers and their mixtures with water have been used as source liquids. The experimental results have shown that low-temperature plasma induced in a liquid-phase flow in the discharge gap between electrodes could effectively decompose hydrogen-containing molecules of organic compounds in a liquid to produce gaseous products with high hydrogen content. It has been also shown that the highest process efficiency is observed while using mixtures of spirits and water as a source material. This may allow using this process in the processing of crude ethanol and other fermentation products of cheap vegetable raw materials. It has been also revealed that some few carbon nanoparticles and nanoparticles of the discharge electrode oxide materials may be also formed in plasma during decomposition of the organic compounds.     

Obtaining of gaseous hydrogen and solid carbon nanoparticles by pyrolysis of liquid-phase media in low-temperature plasma

In this work, it was shown that low-temperature plasma initiated in liquid-phase media in the discharge gap between the electrodes is capable of efficiently decomposing hydrogen-containing molecules of various organic compounds and their mixtures with the formation of gaseous products in which the proportion of hydrogen is more than 90% according to gas chromatography data.In the course of work, an experimental setup for hydrogen production was designed and manufactured, which includes a steel reaction chamber with a cooling jacket, a power supply with adjustable parameters, an ultrasonic generator and transducer, and a gas extraction system.Optimal conditions for the production of hydrogen (yield and selectivity) have been found, and principles have been developed for the automation of the process and the design of a semi-continuous pilot plant in order to increase productivity. The reaction products and the purity of the obtained hydrogen are characterized by a set of instrumental methods of physicochemical analysis, including gas and liquid chromatography, microscopy, calorimetry, and other methods. Preliminary estimates of the energy efficiency, calculated taking into account the heat of combustion of hydrogen and the initial substances, as well as the consumption of electricity, showed an efficiency level of about 60–70%, depending on the composition of the initial mixture. Theoretical calculations of the voltage and current of the discharge were also carried out during the simulation of the process, which are consistent with the experimental data. A by-product of hydrogen production by the acoustoplasma discharge method during the decomposition of organic liquids is carbon, which is formed in the form of agglomerates of nanoparticles of various structures and is deposited during the reaction at the bottom of the reaction chamber. As shown by the results of analyzes and stoichiometric calculations, the formation of these by-products consumes most of the carbon and oxygen contained in the molecules of the initial liquid, thereby the resulting gaseous mixture is significantly enriched in hydrogen. The resulting nanoparticles and their agglomerates can also be used as fillers, dyes, components of composite materials.     

超临界氢存储技术的研究进展

氢能的利用是当今世界发展必然趋势,使用超临界氢存储技术可对氢能进行储存。介绍了超临界氢,并详细分析了超临界储氢、气态压缩储氢和低温液态储氢的优缺点。然后,对超临界储氢技术进行了详细论述,介绍了超临界吸附储氢和低温压力容器储存超临界氢两种技术的研究进展。最后,根据超临界氢存储技术的研究现状,提出了一些对超临界氢存储技术的发展及应用具有一定指导意义的建议。     

燃料电池车车载储氢系统的技术发展与应用现状

综述了燃料电池车车载储氢系统技术，包括高压氢、液氢、金属氢化物、低温吸附、纳米碳管高压吸附以及液体有机氢化物等的研究进展及其车载应用现状。参照燃料电池车对车载储氢系统单位重量储氢密度与体积储氢密度的目标要求，对目前已应用和处于研发阶段的一些储氢技术的性能指标和存在问题进行了分析讨论。同时对目前该领域的若干新的研究报道，如超高压轻质复合容器、混合储氢容器、b.c．c．储氢合金、超级活性碳和“浆液”双相储氢等，也作了简要介绍。     

Hydrogen production in acoustoplasma discharge in a liquid-phase medium flow

In the paper, plasma discharge in a liquid flow at high pressure for use in producing hydrogen gas has been carried out. Methods and equipment for plasma discharge excitation in a liquid medium flow have been developed by the authors. The liquid flow has been directed at excess pressure to the hydrodynamic radiator located at the reactor inlet where an ultrasonic two-phase vapor-liquid flow has occurred at lower pressure due to the pressure difference and decrease in the flow enthalpy. Electric field which intensity exceeds the breakdown threshold of this two-phase medium is generated between electrodes located in the reactor by an external power supply, thus resulting in excitation of the low-temperature quasi-steady plasma glow discharge. Theoretical estimation of the parameters of such discharge has been carried out by the authors. It is shown in the paper that low temperature plasma initiated under the conditions of a liquid-phase medium flow in the discharge gap between electrodes could effectively split hydrogen-containing molecules of organic compounds in a liquid with formation of gaseous products having hydrogen content of more than 90%. In addition, theoretical calculations of the discharge voltage and current which are in good agreement with the experimental results have been carried out in the process simulation. With a mixture of oxygen-containing organic compounds as a raw material, the output capacity of the 50 mL reaction system used in experiments has been around 1.5 l of hydrogen per minute. Decomposition of those compounds in plasma may also result in formation of some solid-phase products, such as carbon nanoparticles and nanoparticles of the discharge electrode oxide materials.