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A study investigated hydrogen permeability in sulfur-cured NBR composites filled with carbon black (CB) and silica, using volumetric analysis across pressures ranging from 1.2 to 92.6 MPa. Both pure NBR and MT CB- and silica-filled NBR exhibited a single sorption mechanism that followed Henry’s law, indicating hydrogen absorption into the polymer chains. In contrast, HAF CB-filled NBR displayed dual sorption behavior, adhering to both Henry’s law and the Langmuir model, which suggests additional hydrogen adsorption at the filler interface. Hydrogen diffusivity in NBR followed Knudsen diffusion at low pressures and bulk diffusion at high pressures. In HAF CB-filled NBR, permeability decreased exponentially with increasing density, while in MT CB- and silica-filled NBR, it declined linearly. The strong polymer-filler interactions in HAF CB significantly influenced permeability. Permeability trends closely correlated with hardness, tensile strength, and density, allowing for the establishment of quantitative relationships between these physical and mechanical properties. These findings indicate that analyzing these properties can predict hydrogen permeability, positioning NBR composites as promising sealing materials for high-pressure hydrogen storage in refueling stations and fuel cell vehicles.

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A high-pressure in-situ permeation measuring system was developed to evaluate hydrogen permeation properties of polymer sealing materials under hydrogen environments up to 100 MPa. This system could perform real-time monitoring of hydrogen permeation following high-pressure hydrogen injection, employing the volumetric method for quantitative measurement. By utilizing a self-developed permeation-diffusion analysis program, this system enabled precise evaluation of permeation properties, including permeability, diffusivity and solubility. To apply the developed system to high-pressure hydrogen permeation tests, hydrogen permeation properties of ethylene propylene diene monomer (EPDM) materials containing silica fillers, specifically designed for use in high-pressure hydrogen environments, were evaluated. Permeation measurements were conducted under pressure conditions ranging from 5 to 90 MPa. Results showed that as pressure increased, hydrogen permeability and diffusivity decreased while solubility remained constant regardless of pressure. Finally, the reliability of this system was confirmed through uncertainty analysis of permeation measurements, with all results falling within an uncertainty of 10.8%.
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Hydrogen gas sensors are essential for industrial safety, environmental monitoring, and the energy sector. As hydrogen infrastructure expands and hydrogen fuel cell vehicles become more widespread, precise detection of hydrogen, which has a wide explosive range, has become increasingly critical. To ensure accurate detection of hydrogen in real-world conditions, sensor technologies must offer high sensitivity, stability, and reproducibility, along with cost-effectiveness, fast response time, and compact design. This study introduces a hydrogen gas sensor based on pressure analysis principles. This sensor was developed to quantitatively evaluate hydrogen uptake, diffusion behavior, solubility, and release characteristics in polymers under high-pressure conditions. Experimental results demonstrated the sensor’s excellent performance, with a stability of 0.2%, a resolution of 0.12 wt·ppm, and a measurement range of 0.12 to 1500 wt·ppm, all within 1 second. Furthermore, the sensor's sensitivity, resolution, and detection range could be tuned to suit different operational environments. Uncertainty analysis showed an expanded uncertainty of 8.8%, confirming the system’s capability for real-time hydrogen detection and characterization. This sensor technology is well-suited for applications in hydrogen refueling stations and fuel cell systems, contributing to the advancement of a safe hydrogen society.
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Development of On-site Analytical Device for Hydrogen Sulfide Using Colorimetric Paper Sensor
Gi-Ja Lee, Yoo-Ri Na, Jae-Chul Lee
J. Korean Soc. Precis. Eng. 2024;41(1):11-18.
Published online January 1, 2024
DOI: https://doi.org/10.7736/JKSPE.023.072
In this study, a highly sensitive analysis device for hydrogen sulfide that could be used quickly and easily on site was developed using a colorimetric paper sensor. To optimize analysis conditions, tests were performed for each function. Performances of the method using laboratory equipment and tools and the method using the developed device for hydrogen sulfide analysis were compared. The trend line of changes in parameter b of the image acquired by the on-site analytical device for hydrogen sulfide was calculated as y = 0.517x - 0.141 with a coefficient of determination (R2) of 0.9874. It was comparable to the method performed at the laboratory level, showing an excellent linearity. Using the calculated trend line as a calibration curve, the detection limit and quantification limit were found to be 2.386 μM and 7.952 μM, respectively. A reproducibility test showed a relative standard deviation of 5.7%, indicating a low dispersion of results.
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Structural Analysis and Optimization of Electrochemical Hydrogen Compressor End Plate Using Taguchi Method and Gray Relational Analysis
Sang Duk Seo, Won Tae Kwon
J. Korean Soc. Precis. Eng. 2023;40(12):955-964.
Published online December 1, 2023
DOI: https://doi.org/10.7736/JKSPE.023.083
The Electrochemical Hydrogen Compressor is an optimal device for compressing low-pressure hydrogen to high-pressure hydrogen. It has a similar structure to the Proton Exchange Membrane Fuel Cell but operates at extremely high pressures, requiring multiple cells sealed with End Plates. The End Plate design must provide initial cell activation support, withstand maximum operating pressure within the stack, and prevent internal gas leakage. This study applies a multi-objective optimization method and grey relation analysis to determine the optimal design parameters for the End Plate based on the activation area of Dummy Cells. Finite Element Method (FEM) analysis is conducted to verify the effectiveness of the optimized End Plate design, considering the uniform pressure distribution with stacked Dummy Cells (1, 3, 6, 12). The analysis reveals that the parameters affecting the uniform pressure distribution include the End Plate design, stack sealing pressure, individual Cell design parameters, and the number of Cell stack layers.
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The Experimental Study of Ion Transportation by Rotating Magnetic Force
Hyeon-Jung Kim, Kwan-Yong Jeong, Hao Guo, Sang-Young Kim
J. Korean Soc. Precis. Eng. 2023;40(2):131-140.
Published online February 1, 2023
DOI: https://doi.org/10.7736/JKSPE.022.084
Hydrogen production using water electrolysis is generally a well-known phenomenon. Hydrogen produced using the water electrolysis method is an environment-friendly energy source called ‘green hydrogen’ that does not emit any environmental pollutants when using renewable energy as an energy source. This study aims to improve the efficiency of hydrogen production by using the ion transportation effect induced by a rotating magnetic force. For this purpose, the experimental conditions for ion transport were determined through an experiment using a copper wire and the rotating magnetic force for water electrolysis was applied using an alkali aqueous solution. Based on the results, an increase in the number of bubbles generated by the rotating magnetic force increased was observed. It is assumed that the efficiency of hydrogen production using water electrolysis can be improved by the rotating magnetic force.
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Design of Fixing Frame with Foam Cored CFRP Sandwich Composite for Hydrogen Storage Vessels
Jae-Chul Lee
J. Korean Soc. Precis. Eng. 2022;39(1):45-50.
Published online January 1, 2022
DOI: https://doi.org/10.7736/JKSPE.021.100
A fixing frame applied with Foam Cored CFRP Sandwich Composite (FCCSC) that replaces SAPH440 steel used in the fixing frame for hydrogen storage was designed, and its structural safety was evaluated. In the design of the fixing frame, FCCSC was implemented by PMI foam core, a Bakelite mount, and Carbon Fiber Reinforced Plastics (CFRP) using woven carbon fiber prepreg. Unlike the steel fixing frame, the FCCSC-applied fixing frame had a cross-section of hollow-rectangular, and its validity was confirmed through finite element analysis. Structural analysis of the designed FCCSCapplied fixing frame and steel fixing frame was performed. Under the extreme load condition of 9G acceleration, the steel fixing frame showed the lowest safety factor of 1.14 based on the yield strength in the opposite direction of gravity. On the other hand, the FCCSC-applied fixing frame showed a safety factor of 7.6 at the maximum principal stress and 3.15 at the shear stress. Through this result of structural analysis, it was verified that the FCCSC-applied fixing frame, which was 25.8% lighter than the steel fixing frame, was 1.8 times safer.
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Extended Replacement Cycle of Perfluorinated Compounds (PFCs) Gas Decomposition Catalysts Using Ca(OH)₂ Adsorbent in Multi-Bed Reactor
Duc Trung Nguyen, Seongyeop Kim, Mingi Choi, Moon Soo Bak, Wonyoung Lee
J. Korean Soc. Precis. Eng. 2020;37(7):555-561.
Published online July 1, 2020
DOI: https://doi.org/10.7736/JKSPE.020.005
Al₂O₃ catalysts, used for the hydrolysis of perfluorinated compounds (PFCs), have a limitation in that their lifetime is abruptly lowered by the generation of hydrogen fluoride (HF) during the reaction. In the PFCs hydrolysis plants, increasing replacement cycles is one of the major challenges in reducing maintenance costs. In this study, the Ca(OH)₂ layer, which decomposes the HF, was inserted between the Co-Zr/Al₂O₃ catalyst layers to increase the catalyst replacement cycle during the CF4 gas decomposition at 750℃. As a result, the decomposition rate was rapidly recovered through the replacement of the adsorbent, and the time to maintain a decomposition rate more than 90% improved by more than eight times compared to the bare catalyst layer without adsorbent.

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  • In-situ pyrolysis based on alkaline medium removes fluorine-containing contaminants from spent lithium-ion batteries
    Hanlin Huang, Chunwei Liu, Zhi Sun
    Journal of Hazardous Materials.2023; 457: 131782.     CrossRef
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