Search Results (10)

In pursuit of sustainable development, worldwide adoption of hydrogen fuel cell vehicles (HFCVs) is growing to cut carbon emissions in the transportation sector. The construction of hydrogen refueling stations (HRSs) is the key to popularizing HFCVs. The popularity of HRSs is hindered by cost, site selection, and user expectations. Selecting mature gas stations with large passenger flow to expand HRSs can improve the accuracy of the hydrogen refueling network. Reducing the range anxiety of HFCV users to improve the path coverage of HFCVs is a favorable way to expand the hydrogen vehicle industry chain. Therefore, this study proposes a bi-level programming model, which considers hydrogen source (HS), hydrogen delivery mode (HDM), initial remaining range, range anxiety, and other factors. The upper-level model is designed to optimize economic costs, including the total chain cost of the HRS. The lower level aims to optimize the range anxiety of HFCV users and more accurately reflect their autonomy by controlling the maximum remaining range of the vehicle. Finally, the expressway in the Liaoning Province of China is taken as an example to verify that the optimization model had the advantages of low hydrogen cost and minimal range anxiety. The cost analysis of several HSs and HDMs was discussed from the perspective of the best site selected, and it was found that the Anshan HS using coal to produce hydrogen and the long tube trailer can provide lower hydrogen cost for the HRS. This method is generalizable to other regions or all types of HFCVs. Full article

The transformation from a fossil fuel economy to a low-carbon economy has reshaped the way energy is transmitted. As most renewable energy is obtained in the form of electricity, using green electricity to produce hydrogen is considered a promising energy carrier. However, most studies have not considered the transportation mode of hydrogen. In order to encourage the utilization of renewable energy and hydrogen, this paper proposes a comprehensive energy system optimization operation strategy considering multi-mode hydrogen transport. Firstly, to address the shortcomings in the optimization operation of existing systems regarding hydrogen transport, modeling is conducted for multi-mode hydrogen transportation through hydrogen tube trailers and pipelines. This model reflects the impact of multi-mode hydrogen delivery channels on hydrogen utilization, which helps promote the consumption of new energy in electrolysis cells to meet application demands. Based on this, the constraints of electrolyzers, combined heat and power units, hydrogen fuel cells, and energy storage systems in integrated energy systems (IESs) are further considered. With the objective of minimizing the daily operational cost of the comprehensive energy system, an optimization model for the operation considering multi-mode hydrogen transport is constructed. Lastly, based on simulation examples, the impact of multi-mode hydrogen transportation on the operational cost of the system is analyzed in detail. The results indicate that the proposed optimization strategy can reduce the operational cost of the comprehensive energy system. Hydrogen tube trailers and pipelines will have a significant impact on operational costs. Properly allocating the quantity of hydrogen tube trailers and pipelines is beneficial for reducing the operational costs of the system. Reasonable arrangement of hydrogen transportation channels is conducive to further promoting the green and economic operation of the system. Full article

Metal hydride hydrogen compressors have attracted great attention due to their reliable safety, environmental friendliness, and the absence of vibration and noise. Herein, the effects of Ti substitution for Zr on the crystal structure and hydrogen compressive performance of Ti_0.92+xZr_0.1−xCr_1.0Mn_0.6Fe_0.4 (x = 0, 0.01, 0.02, and 0.03) are investigated systematically. Among the investigated alloys, the Ti_0.94Zr_0.08Cr_1.0Mn_0.6Fe_0.4 alloy can be considered as a promising candidate for application with a hydrogen capacity of 1.67 wt.% under 8 MPa at 10 °C. Additionally, it exhibits excellent cyclic stability. The desorption pressure at 83.9 °C was determined to be 25 MPa by van’t Hoff fitting plots, which fulfills the requirement of producing over 25 MPa hydrogen pressure in water-bath environments with a high compression ratio of 3.08. The Ti_0.94Zr_0.08Cr_1.0Mn_0.6Fe_0.4 alloy is very promising for hydrogen refueling applications in long-tube trailers and low-pressure gas cylinders. Full article

Due to the properties of zero emission and high energy density, hydrogen plays a significant role in future power system, especially in extreme scenarios. This paper focuses on scheduling hydrogen tube trailers (HTTs) before contingencies so that they can enhance resilience of distribution systems after contingencies by emergency power supply. The whole process is modeled as a two-stage robust optimization problem. At stage 1, the locations of hydrogen tube trailers and their capacities of hydrogen are scheduled before the contingencies of distribution line failures are realized. After the line failures are observed, hydrogen is utilized to generate power by hydrogen fuel cells at stage 2. To solve the two-stage robust optimization problem, we apply a column and constraint generation (C&CG) algorithm, which divided the problem into a stage-1 scheduling master problem and a stage-2 operation subproblem. Finally, experimental results show the effectiveness of enhancing resilience of hydrogen and the efficiency of the C&CG algorithm in scheduling hydrogen tube trailers. Full article

Currently, large-volume type IV composite vessel tube trailers garner significant attention and development within the hydrogen energy storage and transportation industry due to their cost-effectiveness and practicality. This study aims to assess the static strength and sealing performance of the boss structure in order to optimize its design. Firstly, a model of the mouth structure of type IV vessels was constructed to analyze the stress distributions in the boss and liner. Subsequently, innovative boss and liner structures were developed based on the primary mouth structure to investigate the impact of geometric dimensions through finite element analysis. This study revealed that changes in geometrical dimensions led to significant alterations in the stresses of the plastic liner in comparison to metallic bosses. Building upon these findings, the structural safety and sealing performance of the boss and liner structure were further validated through finite element analysis. The outcomes of this research can serve as a reference for guiding the structural design of bosses and aiding in the development of hydrogen storage vessels. Full article

To realize a hydrogen economy, many studies are being conducted regarding the development and analysis of hydrogen carriers. Recently, formic acid has been receiving attention as a potential hydrogen carrier due to its high volumetric energy density and relatively safe characteristics. However, hydrogen refueling systems using formic acid are very different from conventional hydrogen refueling stations, and quantitative risks assessments need to be conducted to verify their safe usage. In this study, a comparative safety analysis of a formic acid hydrogen refueling station (FAHRS) and a gaseous hydrogen refueling station (GHRS) was conducted. Since there is no FAHRS under operation, a process simulation model was developed and integrated with quantitative risk assessment techniques to perform safety analysis. Results of the analysis show that the FAHRS poses less risk than the GHRS, where the vapor cloud explosion occurring in the buffer tank is of greatest consequence. A GHRS poses a greater risk than an FAHRS due to the high pressure required to store hydrogen in the tube trailer. The mild operating conditions required for storage and dehydrogenation of formic acid contribute to the low risk values of an FAHRS. For risk scenarios exceeding the risk limit, risk mitigation measures were applied to design a safe process for GHRS. The results show that the installation of active safety systems for the GHRS allow the system to operate within acceptable safety regions. Full article

In the currently developed hydrogen compression cycle system, hydrogen is compressed through a compressor and stored in a tank at high pressure. In the filling process from A (tube trailer) to B (high-pressure tank), thermal stress in the B arises due to the temperature rise of hydrogen together with the internal pressure increase in the tank. In the study, in order to achieve safe filling, it is necessary to investigate the flow and thermal parameters of the system. Based on the principles of thermodynamics, a thermodynamic prediction model for the temperature change during the hydrogen cycle was established by comprehensively considering the real state of gas, convective heat transfer between hydrogen and the inner wall, heat conduction through the tank wall, and natural convection of the outer wall. Prediction values of temperature, hydrogen charge amountm and heat transfer to the outside were calculated. Additionally, by investigating the performance of the hydrogen refueling station heat exchanger, the heat of the heat exchanger needed to keep the hydrogen temperature within a safe range was calculated. Due to the Joule–Thomson effect, the hydrogen temperature passing through the pressure reducing valve changed, and the changed value in the hydrogen charging cycle was predicted and calculated by calculating the temperature change value at this time. This study provides a theoretical research basis for high-pressure hydrogen energy storage and hydrogenation technology. Full article

The commercialization of eco-friendly hydrogen vehicles has elicited attempts to expand hydrogen refueling stations in urban areas; however, safety measures to reduce the risk of jet fires have not been established. The RISKCURVES software was used to evaluate the individual and societal risks of hydrogen refueling stations in urban areas, and the F–N (Frequency–Number of fatalities) curve was used to compare whether the safety measures satisfied international standards. From the results of the analysis, it was found that there is a risk of explosion in the expansion of hydrogen refueling stations in urban areas, and safety measures should be considered. To lower the risk of hydrogen refueling stations, this study applied the passive and active independent protection layers (IPLs) of LOPA (Layer of Protection Analysis) and confirmed that these measures significantly reduced societal risk as well as individual risk and met international standards. In particular, such measures could effectively reduce the impact of jet fire in dispensers and tube trailers that had a high risk. Measures employing both IPL types were efficient in meeting international standard criteria; however, passive IPLs were found to have a greater risk reduction effect than active IPLs. The combination of RISKCURVES and LOPA is an appropriate risk assessment method that can reduce work time and mitigate risks through protective measures compared to existing risk assessment methods. This method can be applied to risk assessment and risk mitigation not only for hydrogen facilities, but also for hazardous materials with high fire or explosion risk. Full article

Due to environmental pollution and depletion of fossil fuels, hydrogen is becoming an increasingly practical, clean and environmentally friendly option for transportation and energy storage among all green alternative energy sources introduced. Hydrogen storage and delivery is expensive because of the lower energy density per unit volume as compared with conventional fossil fuels. Hence, hydrogen is usually stored in a gaseous state and delivered via tube trailers or pipelines. In this study, a transient structural analysis of a skid structure mounted on a hydrogen tube trailer was performed under shock load induced by road irregularities. The dynamics of the driving trailer according to the unevenness of the road surface were obtained through multibody dynamic simulations considering the full car model equipped with 64 hydrogen tubes. The transient structural analysis of the tube skid was performed by considering the resulting acceleration values as constraints. Through the sequential simulations, we evaluated the structural safety of the designed tube skid mounted on a trailer during hydrogen transport. Full article

Currently, most of the vehicles make use of fossil fuels for operations, resulting in one of the largest sources of carbon dioxide emissions. The need to cut our dependency on these fossil fuels has led to an increased use of renewable energy sources (RESs) for mobility purposes. A technical and economic analysis of a one-stop charging station for battery electric vehicles (BEV) and fuel cell electric vehicles (FCEV) is investigated in this paper. The hybrid optimization model for electric renewables (HOMER) software and the heavy-duty refueling station analysis model (HDRSAM) are used to conduct the case study for a one-stop charging station at Technical University of Denmark (DTU)-Risø campus. Using HOMER, a total of 42 charging station scenarios are analyzed by considering two systems (a grid-connected system and an off-grid connected system). For each system three different charging station designs (design A-hydrogen load; design B-an electrical load, and design C-an integrated system consisting of both hydrogen and electrical load) are set up for analysis. Furthermore, seven potential wind turbines with different capacity are selected from HOMER database for each system. Using HDRSAM, a total 18 scenarios are analyzed with variation in hydrogen delivery option, production volume, hydrogen dispensing option and hydrogen dispensing option. The optimal solution from HOMER for a lifespan of twenty-five years is integrated into design C with the grid-connected system whose cost was $986,065. For HDRSAM, the optimal solution design consists of tube trailer as hydrogen delivery with cascade dispensing option at 350 bar together with high production volume and the cost of the system was $452,148. The results from the two simulation tools are integrated and the overall cost of the one-stop charging station is achieved which was $2,833,465. The analysis demonstrated that the one-stop charging station with a grid connection is able to fulfil the charging demand cost-effectively and environmentally friendly for an integrated energy system with RESs in the investigated locations. Full article