Comprehensive parameter study and evaluation of a reinforcement concept for conformable CFRP tanks for hydrogen storage

The safe operation of hydrogen pipelines and storage tanks is essential for the development of a sustainable hydrogen economy. However, these systems are exposed to significant risks that must be effectively managed to prevent hazardous outcomes. The present study therefore assessed the hazards and risks associated with hydrogen transport through pipelines and storage in tanks using the preliminary hazard analysis (PreHA) on the Hydrogen Incident and Accident Database (HIAD2.1), developed as part of the European Network of Excellence, HySafe. This database reports 34 accidents involving pipelines and 28 accidents involving storage tanks over the past 5 decades. The outcomes of these incidents vary, as majority of pipeline incidents led to fires, whereas storage tank failures were more likely to escalate into explosions. Other reported consequences in both pipeline and storage tanks included leaks with no ignition and near misses which are incidents that did not cause harm but had the potential to escalate into serious accidents. The PreHA analysis further identified corrosion and welding related issues as the main hazards for pipelines, while storage tanks were more often affected by operational failures as well as corrosion. Less frequent but high-impact event of natural disasters also posed catastrophic risks to both systems. Specific to pipeline integrity, it was observed that civil/construction work had a rare but notable impact. The findings of this study provide insights into the critical vulnerabilities of hydrogen pipelines and storage tanks and highlight the need for continuous improvement in safety management practices.

Hydrogen and gas storage tanks installed in facilities are typically vertical cylindrical structures made of steel. To allow for the discharge of stored materials, these tanks are anchored onto concrete blocks with sufficient height. However, this design results in a higher center of gravity, making the tanks more vulnerable to external forces such as earthquakes. This study fabricated a storage tank model and foundation concrete based on the results of the field investigation of the hydrogen storage tank. Then, an artificial earthquake was generated by referring to ICC-ES AC 156, a shaking table test method for non-structural elements. Experimenting on a full-scale structure is ideal; however, a storage tank model was fabricated and settled on the foundation concrete for tri-axial shaking table testing due to limited testing facilities and equipment performance. In the shaking table test, the presence or absence of water inside the storage tank was set as the condition for storing gases and liquids. The seismic behavior characteristics and failure mode of the storage tank model fixed in the foundation concrete were analyzed using the testing results. A seismic fragility curve was drawn up, and the high confidence and low probability of failure (HCLPF) was calculated.

The design and optimization of a cryogenic compressed hydrogen refueling process

Finite element simulation of heat and mass transfer in activated carbon hydrogen storage tank

Hydrogen has been considered as a feasible energy carry for fuel cell vehicles, which offers a clean and efficient alternative for transportation. In the currently developed hydrogen compression cycle system, hydrogen is compressed through a compressor and stored in the tank as high pressure. The hydrogen is filled from high pressure station into hydrogen storage system in fuel cell vehicles. In the study, theoretical and simulation are performed by presenting a mathematical model for the temperature rise during filling process in the hydrogen storage tank at the pressure of 50 MPa compressed hydrogen system. For a high-pressure tank (HPT) that can store hydrogen at a hydrogen filling station, the temperature rise of hydrogen with the pressure change during the filling process, the amount of hydrogen filling in the tank, and the convective heat transfer coefficient in the tank were calculated. The calculated temperature was compared with numerical and theoretical methods. Appropriate theoretical formulas were presented through mathematical modeling for changes that occur when high-pressure storage tanks were filled, and hydrogen properties were analyzed using the REFPROP program. 3D modeling was performed for the high-pressure storage tank, and the analysis was conducted under adiabatic conditions. When the pressure was increased to 50 MPa in the initial vacuum state, and when the residual pressure was 18 MPa, it was 25, 50, 75,and 100 MPa, and hydrogen inside the storage tank of the temperature rise and the amount of hydrogen filling were investigated. The results of this study will be useful for the design and construction of compressed hydrogen tank for hydrogen charging system.

Efficient hydrogen storage methods are crucial for the large-scale application of hydrogen energy. This work studied the effects of fin structure and injection tube on the system performance of a hydrogen storage tank packed with LaNi5 alloy. An axisymmetric finite element model of the metal hydride hydrogen storage tank was established. The fin structure and injection tube were added to the hydrogen storage tank, and the effects of the fin location and injection tube on the efficiency and safety of the hydrogen storage tank during hydriding were analyzed. A parametric study on the wall fin structure and injection tube has been carried out to optimize the design of a hydrogen storage tank, and to improve its efficiency and safety. The hydrogen storage capacity of the optimized tank packed with LaNi5 alloy can reach 1.312 wt%, which is 99% of its maximum capacity, at around 650 s. The results show that the fin structure can improve the heat transfer performance of the storage tank, and that the injection tube can enhance the mass transfer of hydrogen in the tank.

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

To achieve carbon neutrality by 2050, significant progress is being made in developing 50,000 m3 liquefied hydrogen storage tanks. One of the primary design challenges for these tanks is fatigue caused by repeated refilling cycles and seismic events. The influence of welding residual stress on fatigue performance is a critical factor that cannot be overlooked. Given the cryogenic conditions under which these tanks operate, full-scale testing is essential to ensure their safety and reliability. In this study, low-cycle fatigue (LCF) tests were conducted at an extremely low temperature of 20 K on 316L stainless steel specimens. These specimens were specifically designed to replicate the corner configurations of liquefied hydrogen (LH2) storage tanks and included two types of welds for comparison. The test amplitude was determined based on a Level 2 earthquake, representing a significant earthquake that could compromise the structural integrity of the tank. Following the LCF tests, fracture surfaces were analyzed in detail using a scanning electron microscope (SEM) to estimate crack lengths and propagation rates. The results of these observations provided critical insights into the safety of the storage tanks, demonstrating their ability to withstand the operational stresses and environmental conditions they are expected to face during their service life.

Life cycle costs of four engineering measures, including Sponge City, storage tank, large-scale interception and drainage project and deep tunnel project. Three pollution factors, including chemical oxygen demand (COD), ammonia nitrogen (NH3-N) and total phosphorus (TP) affecting the river water quality, are used to calculate the reduction of pollutants and the cost per unit of pollutants in yuan. The economic benefits of the four different methods, and their environmental benefits are quantitatively measured. A comprehensive analysis and evaluation of social benefits are also assessed. Results show that the order of COD reduction cost of non-point source pollution control measures from small to large is: Sponge City = deep tunnel project < storage tank < large interception and drainage project; for NH3-N, the order of cost reduction from small to large is: deep tunnel project < Sponge City < large interception and drainage project < storage tank. For TP, the order of cost reduction from small to large is large cut-off project < Sponge City < deep tunnel project < storage tank.

With the rapid increase in the photovoltaic (PV) installations, the intermittency and the variability of the solar energy sources will lead to the frequent and steep ramping operation of conventional fossil generation. Consequently, energy storage is required for efficient use of the renewable energy source. Hydrogen production via electrolysis can provide both short and long duration capacity as a controllable load to reduce grid fluctuations and improve the resilience of the energy system. Once the hydrogen is produced, it must be stored before it is consumed. High pressure gaseous hydrogen storage is the most popular and mature hydrogen storage technology due to the technical simplicity, reliability, energy efficiency as well as affordability [1]. Compressed hydrogen storage with a fast filling-emptying rate can be used as a hydrogen multiple-purpose station for both stationary fuel cell and fuel cell electric vehicle (FCEV) applications. Although hydrogen electrolyzers, stationary fuel cells, and FCEV refueling stations have been extensively studied, little work has been done integrating these hydrogen technologies with a utility PV field to ensure electric grid stability, maximize PV utilization and efficiently produce and consume hydrogen. A model for a complete system of hydrogen production via electrolysis and high-pressure hydrogen storage was developed. The dynamic performance of different hydrogen storage filling and emptying operations with electrolyzer, stationary fuel cell and FCEV shows the feasibility and flexibility of the integrated hydrogen system.A high-fidelity dynamic model of a Proton Exchange Membrane (PEM) electrolyzer was developed for hydrogen production from PV electricity. A parallel multi-stage hydrogen compression system with cascade tanks for filling/emptying was designed and modeled. A non-adiabatic lumped dynamic model was developed for the storage tank with heat transfer from the tank to ambient air. The Soave-Redlich-Kwong equation of state was adopted to account for the non-ideal gas response of high-pressure gaseous hydrogen [2]. The 1 MW electrolyzer under full load produces hydrogen at 200 Nm3/hr (17.7 kg/hr) and the hydrogen can be compressed up to the maximum pressure of 45 MPa suitable for heavy-duty fuel cell vehicles.The storage tanks can be filled with constant/varied hydrogen flow from the electrolyzer depending on the PV power. The compressor and heat exchanger duties as well as the storage tank pressure and temperature are monitored and controlled. The tanks can be discharged to the stationary fuel cell and/or FCEVs. The dynamic performance of integrated hydrogen system for PV smoothing (filling with varied hydrogen flow in short time-scale), peak shaving (filling and emptying with constant hydrogen flow in long time-scale) and FCEV refueling (cascade filling and emptying) will be presented. The feasibility and flexibility of integrated hydrogen production and storage system for grid operation will be shown.[1] Li, Mengxiao, Yunfeng Bai, Caizhi Zhang, Yuxi Song, Shangfeng Jiang, Didier Grouset, and Mingjun Zhang. "Review on the research of hydrogen storage system fast refueling in fuel cell vehicle." International Journal of Hydrogen Energy 44, no. 21 (2019): 10677-10693.[2] Xiao, Lei, Jianye Chen, Yimei Wu, Wei Zhang, Jianjun Ye, Shuangquan Shao, and Junlong Xie. "Effects of pressure levels in three-cascade storage system on the overall energy consumption in the hydrogen refueling station." International Journal of Hydrogen Energy 46, no. 61 (2021): 31334-31345.

Compared with other hydrogen storage methods, cryo-compressed hydrogen storage has significant advantages in terms of mass hydrogen storage density, volume hydrogen storage density, hydrogen storage cost, safety and evaporation loss. The key component of cryo-compressed hydrogen storage is cryo-compressed hydrogen storage vessel. In order to reasonably design and optimize the performance of cryo-compressed hydrogen storage tank, the author uses carbon fiber and low temperature resin to prepare composite one-way plate from the material, and then makes the one-way plate into relevant splines for testing. The relevant parameters of the spline are tested in the liquid nitrogen temperature zone, such as elastic modulus, Poisson’s ratio, thermal conductivity, etc. Using the relevant mechanical properties of the carbon fiber composite one-way plate obtained from the experiment, the target storage tank is designed to provide the actual storage tank for the subsequent low temperature and high pressure storage tank experiment.

The performance of a grid-tied microgrid with hydrogen storage and a hydrogen fuel cell stack

Pressure vessels in today's chemical plants are employed in a variety of services such as reactors, heat exchangers, storage tanks, waste heat boilers, high pressure fluid reservoirs for heavy mechanical presses, and for storage of rocket propellants. They are also used in traditional and nuclear power plants. Fabrication technologies using thick hot rolled‐welded or bent‐welded steel plate and thick segment forge‐welded steel in a single layer and thin steel plate wrapped welded and fitted in multilayers, and wound steel ribbon or carbon filament are procedures used for major vessels. Reactors for certain processes require anticorrosive layers inside the vessels with the ability for detection of failure in the layer. Special steel is needed for use at high temperatures in the petroleum hydrogenation reactors. This article discusses the fabrication of such vessels and new technologies that have been developed in China and Germany. ASME codes for construction are given as well as details on ASME approved materials. Advantages of ribbon winding and details of fabrication are discussed. Thick steel plate rolled welded and ribbon wound vessel technologies are compared. New developments include, eg, the use of graphite filaments or ribbons in fuel cells for automobiles, and layered vessels for use in long distance transport pipe and storage tanks. Use of the German U‐grooved technology is combined with Chinese technology. Applications for this technology include in vessels for ammonia plants, methanol plants, petrochemical plants, in fluid storage tanks, urea reactors, hydrogen storage tanks, and hot wall hydrogenation reactors. Leak monitoring is important and addressed. Professional organizations important to the pressure vessel technologies are listed.

With the increasing penetration of intermittent renewable resources (e.g., solar and wind) into the power grid, hydrogen production from renewable electrolysis has gained more attention as a large-scale energy storage technology to meet the fluctuating grid demand and improve the resilience of the energy system. Accordingly, the development of economic, efficient and safe hydrogen storage technology is required. High-pressure gaseous hydrogen storage is currently the most suitable solution for long-duration storage due to its technical simplicity, reliability, energy efficiency as well as affordability [1]. Even though compressed hydrogen storage has a fast filling-releasing rate, the increase in the pressure and temperature of hydrogen in the storage tank leads to thermal stress and related safety concerns [2]. With this motivation, a complete system of hydrogen production via electrolysis and high-pressure hydrogen storage was developed. Different filling and releasing cycles and transient responses of the storage tank will be presented.A high-fidelity dynamic model of a Proton Exchange Membrane (PEM) electrolyzer was developed for hydrogen production from an intermittent renewable resource. A parallel multi-stage hydrogen compression system with cascaded filling configuration was modeled and designed. A non-adiabatic lumped dynamic model was developed for the storage tank and the heat conductivity within the tank wall was included. In addition, the thermal stress model was developed to estimate the storage tank stress transient. Different equations of state (e.g., Peng-Robinson or Modified Benedict-Webb-Rubin) were adopted to account for the non-ideal gas response of high-pressure gaseous hydrogen [3]. Under the steady-state condition of 510 kW power, 90 Nm3/hr (i.e., 7.92 kg/hr) of hydrogen can be produced and compressed up to the maximum pressure of 44 MPa. The full capacity of the storage tank would be reached after 72 hr.Different filling and releasing scenarios were implemented depending on the seasons and hydrogen fuel applications. The compressor duty as well as the storage tank pressure and temperature was monitored and controlled. The most effective and economical filling and releasing operation will be presented based on technical and economic analysis.[1] Li, Mengxiao, Yunfeng Bai, Caizhi Zhang, Yuxi Song, Shangfeng Jiang, Didier Grouset, and Mingjun Zhang. "Review on the research of hydrogen storage system fast refueling in fuel cell vehicle." International Journal of Hydrogen Energy 44, no. 21 (2019): 10677-10693.[2] Li, Ji-Qiang, No-Seuk Myoung, Jeong-Tae Kwon, Seon-Jun Jang, and Taeckhong Lee. "A Study on the Prediction of the Temperature and Mass of Hydrogen Gas inside a Tank during Fast Filling Process." Energies 13, no. 23 (2020): 6428.[3] Lemmon, Eric W., Marcia L. Huber, Daniel G. Friend, and Carl Paulina. Standardized Equation for Hydrogen Gas Densities for Fuel Consumption Applications1. No. 2006-01-0434. SAE Technical Paper, 2006.

This paper describes a model of hydrogen blowdown dynamics for storage tanks needed for hydrogen safety engineering to accurately represent incident scenarios. Heat transfer through a tank and pipe walls affects the temperature and pressure transients inside the storage vessel and at the nozzle exit, and thus the characteristics of the resulting hydrogen jet in the case of loss of containment. Current non-adiabatic blowdown models are validated against experiments performed with hydrogen storage tanks at only ambient temperature. The effect of heat transfer for cryo-compressed hydrogen is more significant due to a larger difference of temperature between the stored hydrogen and the surrounding atmosphere, especially in case of equipment insulation failure during an incident. Our previous work demonstrated that the heat transfer through a discharge pipe wall can significantly affect the mass flow rate of cryogenic hydrogen releases. Thoroughly validated models of non-adiabatic blowdown dynamics for cryo-compressed hydrogen are missing at the moment. This work develops further the non-adiabatic blowdown model at ambient temperature using the under-expanded jet theory developed at Ulster University, to expand it to cryo-compressed hydrogen storage tanks. The non-ideal behaviour of cryo-compressed hydrogen due to low temperatures is taken into account through the high-accuracy Helmholtz energy formulations. The developed model includes effect of heat transfer at both the tank and the discharge pipe walls. The model is thoroughly validated against sixteen tests on blowdown of hydrogen storage tanks with initial pressure 0.6–20 MPa ab and temperature 80–310 K, through release nozzle of diameter in the range 0.5–4.0 mm, performed within the PRESLHY project. The model well reproduces the experimental pressure and temperature recordings in the storage tank during the entire blowdown duration for the whole set of sixteen tests. In conjunction with the volumetric source model, explained in detail, the physical model allows to perform CFD simulations accurately reproducing the temperature distribution in time and space for the cryogenic hydrogen jet experiment.