Refueling Stations Research Articles

Closed-form P-I diagram based on flextural and shear failure for ptotective wall

Protective walls are crucial structures in mitigating damage from explosions, particularly in environments such as gas refueling stations. However, evaluating their performance typically involves intricate numerical analyses to derive Pressure-Impulse (P–I) diagrams. This paper presents a novel closed-form solution for deriving P–I diagrams specifically tailored for protective walls, considering flexural and shear resistance. By assuming perfect plastic resistance, the proposed solution offers an efficient alternative to numerical analysis, particularly beneficial in preliminary design stages. The validity of the closed-form solution is demonstrated through comparisons with numerically derived P–I diagrams, showing promising results across various design parameters. This approach enhances the accessibility and ease of designing protective walls for blast resistance, contributing to improved safety measures in critical infrastructure.

Multi-objective optimization of membrane cavity curve of diaphragm compressor and its verification

According to the trend of compressor upgrades in hydrogen refueling stations, this article optimizes the single exponential curve of membrane chamber volume and diaphragm stress that performs poorly. First, set the optimization goals as the membrane cavity volume and the arc length of the curve, use the MOPSO algorithm to optimize the curve, and fit the optimization results to obtain a new curve mathematical model. Then, select three curves for comparison. Theoretical calculations and finite element simulations were performed on the membrane cavity volume and diaphragm stress, and the theoretical calculation methods and results were verified with the help of existing experiments. Finally, it was found that the new curve can increase the membrane cavity volume and reduce the diaphragm stress requirement by changing its own parameters, and the new curve has a small amount of cavity volume near the transition point, which has little impact on the membrane cavity volume. Under the same maximum radial stress, the membrane cavity volume of the new curve can be increased by 5.56% compared to the single exponential curve, while under the same membrane cavity volume, the new curve can reduce the maximum stress on the gas side by 8.9% compared with the single exponential curve, and the maximum stress on the oil sides is reduced by 9.8%.

An optimal standalone wind-photovoltaic power plant system for green hydrogen generation: Case study for hydrogen refueling station

Sustainability goals include the utilization of renewable energy resources to supply the energy needs in addition to wastewater treatment to satisfy the water demand. Moreover, hydrogen has become a promising energy carrier and green fuel to decarbonize the industrial and transportation sectors. In this context, this research investigates a wind-photovoltaic power plant to produce green hydrogen for hydrogen refueling station and to operate an electrocoagulation water treatment unit in Ostrava, Czech Republic's northeast region. The study conducts a techno-economic analysis through HOMER Pro® software for optimal sizing of the power station components and to investigate the economic indices of the plant. The power station employs photovoltaic panels and wind turbines to supply the required electricity for electrolyzers and electrocoagulation reactors. As an off-grid system, lead acid batteries are utilized to store the surplus electricity. Wind speed and solar irradiation are the key role site dependent parameters that determine the cost of hydrogen, electricity, and wastewater treatment. The simulated model considers the capital, operating, and replacement costs for system components. In the proposed system, 240 kg of hydrogen as well as 720 kWh electrical energy are daily required for the hydrogen refueling station and the electrocoagulation unit, respectively. Accordingly, the power station annually generates 6,997,990 kWh of electrical energy in addition to 85595 kg of green hydrogen. Based on the economic analysis, the project's NPC is determined to be €5.49 M and the levelized cost of Hydrogen (LCH) is 2.89 €/kg excluding compressor unit costs. This value proves the effectiveness of this power system, which encourages the utilization of green hydrogen for fuel-cell electric vehicles (FCVs). Furthermore, emerging electrocoagulation studies produce hydrogen through wastewater treatment, increasing hydrogen production and lowering LCH. Therefore, this study is able to provide practicable methodology support for optimal sizing of the power station components, which is beneficial for industrialization and economic development as well as transition toward sustainability and autonomous energy systems.

Designing an optimal multi-energy system with fast charging and hydrogen refueling station under uncertainties

As the demand for battery-powered and hydrogen-based electric vehicles continues to rise, the need for integrated charging and refueling systems with energy systems becomes more critical. Therefore, it is crucial to consider the stations serving diverse vehicle users during the system design process. This paper presents an optimal sizing strategy for a multi-energy system that covers clean energy sources and two energy storage technologies under the presence of a fast-charging station and a hydrogen refueling station for various types of car users. For the considered system, the optimal sizing problem aims to minimize the loss of power supply probability (LPSP) and annualized total life cycle cost (TLCC) through a two-stage stochastic programming-based multi-objective optimization approach. Using a scenario-based approach, the study considers the uncertainties associated with renewables, homeowner’s vehicle demands, and energy demands from homes and stations. Different cases are produced to evaluate the impacts of the different stations with the availability of various electric vehicle profiles under different levels of reliability. The TLCC decreases if LPSP increases in each case. Also, the cost of installing a fast charging station is significantly lower than that of a hydrogen refueling station for all LPSP limits. Moreover, the overall cost of the system design is at its lowest when homeowners’ vehicles provide vehicle-to-grid services. It is worth noting that when the station loads which come from the customers’ vehicle increase by 10%, the TLCC increases by 1.19%. Additionally, the revenue from hydrogen refueling station is approximately 70% less than the fast charging station.

Green hydrogen as a source of renewable energy: a step towards sustainability, an overview

AbstractHydrogen has emerged as a promising energy source for a cleaner and more sustainable future due to its clean-burning nature, versatility, and high energy content. Moreover, hydrogen is an energy carrier with the potential to replace fossil fuels as the primary source of energy in various industries. In this review article, we explore the potential of hydrogen as a part of the global energy mix and the current state of its development. The majority of hydrogen production currently occurs through steam methane reforming, which produces significant greenhouse gas emissions and limits the potential of hydrogen as a clean energy source. Significant investment and advancements in renewable hydrogen production through electrolysis are necessary to overcome this limitation. There is also a growing demand for hydrogen infrastructure, including hydrogen refueling stations and storage and transportation systems, which are crucial for the growth and success of the hydrogen industry. The future of hydrogen as a part of the global energy mix will depend on continued investment and commitment to develop and commercialize this promising energy source. Our review also explores the relationship between eco-industrial parks and hydrogen production, including the benefits and challenges of hydrogen production in EIPs and the various technologies being developed to facilitate this process.

Performance improvement of metal hydride hydrogen compressors using electromagnetic induction heating

While there are some hydrogen refueling stations (HRS) functioning in different parts of the world, their use is not widespread enough, primarily due to their expensive cost. Hydrogen compression is a main contributor to the capital and operation costs of the HRS. By improving H2 compression technology, it is possible to optimize the infrastructure for refueling with hydrogen in terms of cost and performance. The use of metal hydride hydrogen compressors (MHHCs), which have the potential to be inexpensive and have the ability to use waste heat and renewable energy sources for the H2 compression, is a promising solution to overcome this issue. The duration of the H2 compression cycle is nevertheless a serious challenge due to the metal hydride (MH) bed's low heat conductivity. As a heating technique to improve the performance of MHHCs, electromagnetic induction (EMI) is examined numerically for the first time in this work. The dynamic behavior of a two-stage MHHC with each MH reactor having an external heat exchanger and being ringed by a copper coil traversed by an alternating current is described by a two-dimensional mathematical model, which was established and successfully verified by the reference data. Numerical simulations were performed with the help of this model, and the findings showed that the EMI heating method is faster than the heat transfer fluid (HTF) heating technique. For instance, at a delivery temperature of 373 K and a supply pressure of 20 bar, it is possible to produce 106 NL H2 per kilogram of HPMH at a pressure of 97 bar with a 74 % shorter compression time than with the HTF heating technique.

A novel type of additively manufactured high pressure mini-channel heat exchanger for precooling in hydrogen refueling stations

During refueling supercritical hydrogen into high pressure storage tanks, the fluid has to be cooled down to temperatures between -33°C and -40°C before entering the vehicle fuel tank. This cooling takes place while the hydrogen is at a pressure of up to 87.5 MPa. The requirements for the heat exchanger performing this task are very high. It has to be pressure resistant, compact enough to fit in the dispenser column and provide a high thermal performance to ensure a fast refueling with high mass flow rates. Only few conventional manufactured heat exchangers are able to fulfil these requirements. With the rise of additive manufacturing technology, especially laser powder bed fusion, new heat exchangers produced without use of conventional joining technologies can be realized. This manuscript presents a new type additively manufactured of mini-channel heat exchanger. It is developed in a joint research project involving the Leibniz University Hanover and an industrial heat exchanger manufacturer. The apparatus has a design pressure of 105 MPa and will be suited to be used in hydrogen refueling stations. The thermal requirements and the design of the apparatus are described. Thermal power and pressure drop for the full-size heat exchanger are calculated via a cell model. Scaled smaller heat exchangers made of 1.4404 stainless steel are additively manufactured via laser powder bed fusion (LPBF). The thermofluiddynamical performance of the scaled apparatus is measured in a testbench to verify the applicability of the used correlations. Deviations in hydraulic diameter and surface roughness are taken into account. Existing correlations are fitted to the new geometry.

Analysis of Hydrogen Value Chain Events: Implications for Hydrogen Refueling Stations’ Safety

Renewable hydrogen is emerging as the key to a sustainable energy transition with multiple applications and uses. In the field of transport, in addition to fuel cell vehicles, it is necessary to develop an extensive network of hydrogen refueling stations (hereafter HRSs). The characteristics and properties of hydrogen make ensuring the safe operation of these facilities a crucial element for their successful deployment and implementation. This paper shows the outcomes of an analysis of hydrogen incidents and accidents considering their potential application to HRSs. For this purpose, the HIAD 2.0 was reviewed and a total of 224 events that could be repeated in any of the major industrial processes related to hydrogen refueling stations were analyzed. This analysis was carried out using a mixed methodology of quantitative and qualitative techniques, considering the following hydrogen value chain: production, storage, delivery and industrial use. The results provide general information segmented by event frequency, damage classes and failure typology. The analysis shows the main processes of the value chain allow the identification of key aspects for the safety management of refueling facilities.

Optimal techno-economic design of PV-wind hydrogen refueling stations (HRFS) for 20 selected Saudi sites

The current study proposes a model of an autonomous HRFS installed on different sites in 20 Saudi cities powered by renewable clean energy sources. The station is fully powered by photovoltaic (PV) panels and wind turbines involving an electrolyzer and hydrogen tank for producing and storing hydrogen. Three scenarios are investigated to propose an optimized model, namely Scenario 1 containing (PV-Wind-Battery) system, Scenario 2 with (Wind-Battery) technologies, and Scenario 3 with (PV-Battery) components. The HRFS is expected to feed the load hydrogen demand of 25 hydrogen cars with a storage tank capacity of 5 kg. The simulation is carried out using the well-known HOMER software and the description of the technical parameters of the renewable plant together with a detailed economic feasibility for the investigated cities are also performed. Furthermore, the optimization process executed demonstrates a competitive levelized cost of energy (LCOE) and levelized cost of hydrogen (LCOH) especially for the third scenario with a LCOH varying within $12–15.9/kg and LCOE in range $ 0.332–0.414/kWh, for all 20 cities. For instance, encouraging lowest values of net present cost (NPC) and LCOE are obtained for the futuristic NEOM mega city relatively to the first and third scenarios with values (NPC = $1,576,000, LCOE = $ 0.627/kWh) and (NPC = $830,494, LCOE = $ 0.332/kWh), respectively. On another hand, thorough analysis of PV/Wind hydrogen technoeconomic operation is provided including improvements recommendations, scenarios comparison and environmental impact discussion.

Prediction of hydrogen leakage location and intensity in hydrogen refueling stations based on deep learning

The common risk of high-pressure hydrogen leakage seriously affects the safety of hydrogen refueling stations (HRS). In this study, we have developed a hybrid model (WD-KNN-CNN) based on wavelet denoising (WD) and deep learning to predict the hydrogen leakage location and intensity in HRS. The raw data were calculated using validated Computational Fluid Dynamics (CFD), and the WD-processed raw data were utilized as input data for the hybrid model. The K-nearest Neighbors (KNN) is employed to identify the leak location, while a two-dimensional Convolutional Neural Network (CNN) is utilized to extract temporal and spatial distribution features from the concentration sequence for intensity prediction. Bayesian optimization is applied to determine the optimal hyperparameter combination for the model. The results demonstrate that the model achieves a prediction accuracy of 99.14% for leak location and 97.42% for intensity level. Furthermore, through the reduction of sensor quantity, we tested the model's performance and found that utilizing 14 sensors as input resulted in 91.3% accuracy for leak location and 90.8% for intensity level prediction. This hybrid model provides a method for safety monitoring in HRS and offers guidance for personnel response during leak incidents.

Expansion of Next-Generation Sustainable Clean Hydrogen Energy in South Korea: Domino Explosion Risk Analysis and Preventive Measures Due to Hydrogen Leakage from Hydrogen Re-Fueling Stations Using Monte Carlo Simulation

Hydrogen, an advanced energy source, is growing quickly in its infrastructure and technological development. Urban areas are constructing convergence-type hydrogen refilling stations utilizing existing gas stations to ensure economic viability. However, it is essential to conduct a risk analysis as hydrogen has a broad range for combustion and possesses significant explosive capabilities, potentially leading to a domino explosion in the most severe circumstances. This study employed quantitative risk assessment to evaluate the range of damage effects of single and domino explosions. The PHAST program was utilized to generate quantitative data on the impacts of fires and explosions in the event of a single explosion, with notable effects from explosions. Monte Carlo simulations were utilized to forecast a domino explosion, aiming to predict uncertain events by reflecting the outcome of a single explosion. Monte Carlo simulations indicate a 69% chance of a domino explosion happening at a hydrogen refueling station if multi-layer safety devices fail, resulting in damage estimated to be three times greater than a single explosion.

An integrated uncertainty analysis method for the risk assessment of hydrogen refueling stations

In order to assess more rigorously the risks of hydrogen refueling stations (HRSs) with consideration of uncertainties, an uncertainty analysis method integrating the Hydrogen Plus Other Alternative Fuels Risk Assessment Models (HyRAM+), Monte Carlo simulation, and Latin Hypercube Sampling (LHS) method is proposed in this paper. In order to discuss and demonstrate the potential ability of the proposed method, the leak risk of a 35 MPa dispenser at a HRS is assessed. The results indicate that the proposed method can effectively quantify the leak risk uncertainty of the dispenser at a HRS. These uncertainties considered have significant effects on the leak risks of the dispenser, and the risk contribution of jet fire is much larger than that from explosion. Moreover, the leak risk of the dispenser is underestimated by the HyRAM+, so it should be used by combining a reliable safety factor. Current work can provide a more accurate method for the risk assessment and performance-based design of HRSs.

Technical feasibility and financial assessment of autonomous hydrogen refuelling stations fully supplied by mixed renewable energy systems for twenty selected sites located in France

Technical feasibility and financial assessment of autonomous hydrogen refuelling stations fully supplied by mixed renewable energy systems for twenty selected sites located in France

Numerical Simulation of the Dovetail Tee and Hydraulic Optimization of the Height Difference for Pipeline in a Liquefied Natural Gas Filling Station

Certain configurations of liquefied natural gas refueling stations exhibit a deficiency in managing boil-off gas. Furthermore, the ill-conceived linkage between the submersible pump and the gas storage tank pipeline leads to impeded natural gas transmission. This study employed the computational fluid dynamics (CFD) methodology to scrutinize the hydrodynamic attributes of the T-type tee and dovetail tee configurations implemented in the pipeline design connecting the submersible pump and storage tank in a liquefied natural gas (LNG) filling station across diverse operational scenarios. The T-type tee induces detachment of the primary flow from the inner wall due to inertial forces, which results in vortex formation and heightened resistance, accompanied by increased energy dissipation. The transition of the rounded inner wall of the dovetail tee results in the reduction of eddy current generation and a smaller separation zone, thus minimizing resistance and energy loss. The maximum static differential pressure between the inlet and outlet of the dovetail tee is reduced by 52.52% compared to that of the T-type tee. In practical engineering applications, the use of dovetail tees leads to a reduction in the height difference for the pipeline by 17.58%, resulting in more uniform and stable flow rates and pressures in the flow field. These improvements contribute to engineering efficiency and environmental sustainability and are particularly evident in the design of LNG filling stations.

Analysis of the Development Status and Industrial Policies of the Hydrogen Energy Industry in Zhangjiagang City

China is currently building hydrogen refueling stations in Beijing, Shanghai, and Zhengzhou. Moreover, there are currently numerous medium-sized hydrogen refueling stations under construction with a capacity of over 400KG/D. From planning, design, construction to operation, hydrogen stations with long-term operational capabilities are required to analyze and develop the system, ensuring the scientific nature of technology and the economic efficiency of operation. The core facilities of the hydrogen refueling station are mainly gas storage tanks. Air compressors and various control systems. At present, the existing hydrogen production stations and core facilities under construction mainly adopt the form of "import+domestic products", basically establishing the conditions for national production. But it is necessary to strengthen the implementation of current standards, the establishment of inspection instruments, and supervision and management.

Application and Analysis of Liquid Organic Hydrogen Carrier (LOHC) Technology in Practical Projects

In contemporary times, the utilization of liquid organic hydrogen carriers (LOHCs) has gained prominence due to their high volumetric storage density and material properties closely resembling conventional fuels. Numerous countries are incorporating LOHCs in hydrogen demonstration initiatives, encompassing applications such as hydrogen refueling stations, hydrogen-powered ships, and trains. This paper conducts a comprehensive review of seventeen LOHC projects, spanning Germany, Europe, and other nations, presenting detailed project specifications. This review includes information on project consortiums, funding sources, covered supply chains, transport modalities, and employed technologies. Through a global evaluation of LOHC projects, this review underscores the promising and competitive nature of LOHCs as a viable option for the large-scale and long-distance storage and transportation of hydrogen. The future development of this field is discussed at in the last section.

Effects of pressure ratio allocation on the flow characteristics in a five-stage ionic liquid compressor

Ionic liquid compressors are a new type of hydrogen compressor technology with significant advantages when applied to high-pressure hydrogen refueling stations, where multi-stage compression is an ideal solution. The utilization of a liquid piston introduces complex two-phase flow phenomena within the cylinders, and understanding the characteristics of two-phase flow is crucial for the thermodynamic performance of the compressor. For the multi-stage compressors, pressure ratio allocation has a significant influence on the structural design and energy conversion efficiency of the compressor, however, there is a lack of relevant research in the existing studies. In this paper, the compression cylinder structures of a five-stage ionic liquid compressor under three pressure ratio allocation strategies are designed, and then the two-phase flow characteristics inside the cylinder are numerically investigated. Based on the analysis of the two-phase flow pattern in the cylinder, the minimum initial liquid heights in each stage that ensure the solid piston is not exposed are determined, and the escape characteristics of ionic liquid and the energy efficiency of the ionic liquid compressor were then analyzed. Under the same total pressure ratio and flow rate, when the consumption cost of ionic liquid was considered as a secondary factor, the strategy of equal pressure ratio allocated for five stages was recommended as the compressor efficiency was higher with better heat transfer performance.

Safety resilience evaluation of hydrogen refueling stations based on improved TOPSIS approach

The traditional use of TOPSIS evaluation for assessing the resilience of hydrogen refueling stations results in overly one-sided outcomes and fails to identify the indicators that have a significant impact on the resilience of the stations. Therefore, this paper proposes an improved method for evaluating the safety resilience of hydrogen refueling stations based on CRITIC-DEMATEL and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). The CRITIC-DEMATEL combination weighting method is employed to determine weights, thus improving the TOPSIS method. This method is then applied to assess the resilience level of hydrogen refueling stations. Then, introducing a Conditional Logistic Regression model identifies indicators with significant impact on resilience. The improved TOPSIS method enhances the reliability and accuracy of evaluation results. The Conditional Logistic Regression model provides a more accurate delineation of the impact size of indicators on the safety resilience of hydrogen refueling stations compared to traditional methods.

Research Progress and Application Prospects of Solid-State Hydrogen Storage Technology.

Solid-state hydrogen storage technology has emerged as a disruptive solution to the "last mile" challenge in large-scale hydrogen energy applications, garnering significant global research attention. This paper systematically reviews the Chinese research progress in solid-state hydrogen storage material systems, thermodynamic mechanisms, and system integration. It also quantitatively assesses the market potential of solid-state hydrogen storage across four major application scenarios: on-board hydrogen storage, hydrogen refueling stations, backup power supplies, and power grid peak shaving. Furthermore, it analyzes the bottlenecks and challenges in industrialization related to key materials, testing standards, and innovation platforms. While acknowledging that the cost and performance of solid-state hydrogen storage are not yet fully competitive, the paper highlights its unique advantages of high safety, energy density, and potentially lower costs, showing promise in new energy vehicles and distributed energy fields. Breakthroughs in new hydrogen storage materials like magnesium-based and vanadium-based materials, coupled with improved standards, specifications, and innovation mechanisms, are expected to propel solid-state hydrogen storage into a mainstream technology within 10-15 years, with a market scale exceeding USD 14.3 billion. To accelerate the leapfrog development of China's solid-state hydrogen storage industry, increased investment in basic research, focused efforts on key core technologies, and streamlining the industry chain from materials to systems are recommended. This includes addressing challenges in passenger vehicles, commercial vehicles, and hydrogen refueling stations, and building a collaborative innovation ecosystem involving government, industry, academia, research, finance, and intermediary entities to support the achievement of carbon peak and neutrality goals and foster a clean, low-carbon, safe, and efficient modern energy system.

Negative net global warming potential hydrogen production through biomass gasification combined with chemical looping: Environmental and economic assessments

The integration of biomass gasification (BG) with chemical looping hydrogen production (CLHP) offers one prospective approach for green hydrogen production. The environmental and economic assessments are conducted to evaluated the sustainable performance of the BG-CLHP system during the hydrogen production cycle (HPC). The results showed that the environmental impacts of BG-CLHP are concentrated in freshwater aquatic ecotoxicity (FAETP), human toxicity (HTP), and acidification (AP). The BG-CLHP system can provide a more cost-competitive hydrogen supply solution for hydrogen refueling stations compared the offshore wind or photovoltaic (PV) powered electrolysis, given the same hydrogen production target. For global warming potential (GWP) and cost, the BG-CLHP demonstrates excellent integrated performance with GWP values of −15.13 and −17.00 kg CO2, eq/kg H2, for the Air case and Oxygen case, and the costs of 3.05 and 2.82 $/kg H2, respectively, and sensitivity analysis reveals that the CLHP stage is the primary contributor to GWP. Compared with existing hydrogen production routes, BG-CLHP can still be improved in terms of costs and the technical maturity, however, the excellent negative GWP properties of BG-CLHP make it will play a more important role in future large-scale hydrogen production.