• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.102-109
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• 2023

In realizing a hydrogen society, it is important to secure the safety of the hydrogen refueling station, which is the facility where consumers can easily meet hydrogen. The hydrogen refueling station consists of compressed gas facilities that store high-pressure hydrogen, and there is a risk that the high-pressure compressed gas facility will rupture due to a fire explosion due to hydrogen leakage in the facility or the influence of surrounding fires. Accordingly, the Korea Gas Safety Corporation is making every effort to find out risk factors from the installation stage, reflect them in the design, and secure safety through legal inspection. In this study, a TNT explosion demonstration test using a protection wall was conducted to confirm the safety effect of the protection wall installed at the hydrogen refueling station, and the empirical test results were compared and verified using FLACS-CFD, a CFD program. As a result of the empirical test and CFD analysis, it was confirmed that the effect of reducing the explosion over-pressure at the rear end of the protection wall decreased from 50% to up to 90% depending on the location, but the effect decreased when it exceeded a certain distance. The results of the empirical test and computer analysis for verifying the safety of the protection wall will be used in proposals for optimizing the protection wall standards in the future.

• Bulletin of the Korean Chemical Society
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• v.23 no.1
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• pp.75-80
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• 2002

Cycle life tests have been carried out to evaluate the influence of safety valve pressure on valve regulated lead/acid batteries under deep cycling applications. Batteries were cycled at 5 hour rates at 100% DOD, and safety valve pressure was set to 1.08 and 2.00 bar, respectively. The batteries lost 248.3 g and 235.3 g of water for each case after about 1,200 cycles, but the cyclic performances of the batteries were comparable. Most of the gas of the battery during discharging was hydrogen, and the oxygen concentration increased to 18% after 3 hours of charging. The micro structure of the positive active materials was completely changed and the corrosion layer of the positive grid was less than $50{\mu}m$, regardless of the pressure of the safety valve after cycle life tests. The cause of discharge capacity decrease was found to be water loss and the shedding of the positive active materials. The pressure of safety valve does not give little effect to the cyclic performances and the failure modes of the gelled electrolyte valve-regulated lead acid batteries.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.3
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• pp.240-246
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• 2022

This study was conducted to develop a domestic product for a flow control valve for a hydrogen refueling station, and a domestic prototype was manufactured and the durability performance evaluation was conducted through comparison with an imported products. The stress generated by the internal pressure was checked and safety was confirmed using a commercial structural analysis program, ABAQUS, in accordance with the withstand pressure test standards. In addition, after identifying the weak areas the fatigue life was predicted through a commercial software, fe-safe. This fatigue analysis showed that the hydrogen gas repeated test criteria were satisfied.

• Journal of Ocean Engineering and Technology
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• v.38 no.3
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• pp.87-102
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• 2024

Given the inadequate regulatory framework for liquefied hydrogen gas storage tanks on ships and the limitations of the IGC Code, designed for liquefied natural gas, this study introduces a critical assessment procedure to ensure the safety and suitability of such tank designs. This study performed a heat transfer analysis for boil-off gas (BOG) calculations and established separate design load cases to evaluate the yielding and buckling strength. In addition, the study assessed methodologies for both high-cycle and low-cycle fatigue assessments, complemented by comprehensive structural integrity evaluations using finite element analysis. A comprehensive approach was developed to assess the structural integrity of Type C tanks by conducting crack propagation analysis and comparing these results with the IGC Code criteria. The practicality and efficacy of these methods were validated through their application on a 23K-class liquefied hydrogen carrier at the concept design stage. These findings may have important implications for enhancing safety standards and regulatory policies.

• Journal of the Korean Institute of Gas
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• v.27 no.1
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• pp.48-56
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• 2023

Currently, Hydrogen compressor is maintained and managed according to the safety management regulations of the operator. But it is not based on technical standards, so it is necessary to establish based on reliability. In this paper, hydrogen compressor taxonomy by ISO 14224 standard reviewed for hydrogen compressor operated by KOGAS-Tech hydrogen vehicle refueling station to establish 9-stage taxonomy, and FMEA was conducted to establish RCM strategy specified in SAE JA1011, and 1012. It is expected that results of taxonomy and RCM strategy will be used as basic data for development of standards for verifying the performance of compressors.

• Journal of the Korea Safety Management & Science
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• v.22 no.2
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• pp.7-13
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• 2020

Sludge incineration facilities are socially recognized as a hate facility. Therefore, a careful deodorization plan must be established. Therefore, the incineration facility must conduct research on odor ventilation. In this study, a odor diffusion simulation in an incineration facility was conducted and analyzed. In particular, research was carried out on carry-in rooms, pre-treatment rooms, and storage facilities for crops, which are expected to rapidly spread odor. As a result, ammonia 1.62, hydrogen sulfide 0.63, and acetaldehyde 0.73 were found in the transfer room. In addition, pretreatment rooms and stencil storage facilities were found to be lower than regulatory standards.

• Transactions of the Korean hydrogen and new energy society
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• v.32 no.3
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• pp.172-179
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• 2021

The drop impact analysis was carried out on Type 4 pressure containers, and the degree of damage to the falling environment was predicted and determined using smoothed particle hydrodynamics (SPH) techniques. The purpose of the design and the optimization process of the winding pattern of the pressure vessel of the composite material is to verify the safety of the container in actual use. Finally, an interpretation process that can be implemented in accordance with domestic test standards can be established to reduce the cost of testing and containers through pre-test interpretation. The research on the fall analysis of pressure vessels of composite materials was conducted using Abaqus, and optimization was conducted using ISIGHT. As a result, the safety of composite pressure vessels in the falling environment was verified.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.2
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• pp.162-168
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• 2023

The fast refueling process of compressed hydrogen has an important impact on the filling efficiency and safety. With the development and use of hydrogen energy, the demand for precision measurement of filling hydrogen thermodynamic parameters is also increasing. In this paper, the compressibility factor calculation model of high-pressure hydrogen gas was studied, and the basic equation of state and thermo-physical parameters were calculated. The hydrogen density data provided by the National Institute of Standards and Technology was compared with the calculation results of each model. Results show that at a pressure of 0.1-100 MPa and a temperature of 233-363 K, the calculation accuracy of the Zheng-Li equation of state was less than 0.5%. In the range of 0.1-70 MPa, the accuracy of Redich-Kwong equation is less than 3%. The hydrogen pressure more influences on the compressibility factor than the hydrogen temperature does. Using the Zheng-Li equation of state to calculate the compressibility factor of on-board high pressure hydrogen can obtain high accuracy.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.4
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• pp.384-392
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• 2013

Objective: This study inspected incident cases, legal control levels, and GHS(Globally Harmonized System of Classification and Labeling of Chemicals) classification results of strong acids such as hydrogen fluoride, hydrogen chloride, nitric acid, and sulfuric acid, which have been responsible for many recent chemical accidents. As a result, it is deemed necessary for legal control levels of these strong acids to be revised and GHS classification be managed nation-wide. Methods: This study inspected incident cases and legal control levels for strong acids such as hydrogen fluoride, hydrogen chloride, nitric acid, and sulfuric acid. The study analyzed and compared chemical information status and GHS classification results. Results: There were 76 domestic incidents involving strongly acidic hazardous materials over the five years between 2007 and 2011. They include 37 leakage incidents(46.7%) within a workplace, 30 leakage incidents(39.5%) during transportation, and nine leakage incidents(13.8%) following an explosion. The strongly acidic materials in question are defined and controlled as toxic chemicals according to the classes of Substances Requiring Preparation for Accidents, Managed Hazardous Substance, Hazardous Chemical(corrosive) as set forth under the Enforcement Decree of the Toxic Chemicals Control Act and Rules on Occupational Safety and Health Standards of Occupational Safety and Health Act. Among them, nitric acid is solely controlled as a class 6 hazardous material, oxidizing liquid, under the Hazardous Chemicals Control Act. The classification results of the EU ECHA(European Chemicals Agency) CLP(Commission Regulation(EC) No. 790/2009 of 10 August 2009, for the purposes of its adaptation to technical and scientific progress, Regulation(EC) No 1272/2008 of the European Parliament and of the Council on classification, labeling and packaging of substances and mixtures) and NIER (National Institute of Environmental Research) are almost identical for the three chemicals, with the exception of sulfuric acid. Much of the classification information of NITE (National Institute of Technology and Evaluation) and KOSHA(Korea Occupational Safety and Health Agency, KOSHA) is the same. NIER provides 12(41.4%) out of 29 classifications, as does KOSHA.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.4
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• pp.342-352
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• 2020

Objectives: The characteristics of research workers are different from those working in the manufacturing industry. Furthermore, the reagents used change according to the research due to the characteristics of the laboratory, and the amounts used vary. In addition, since the working time changes almost every day, it is difficult to adjust the time according to exposure standards. There are also difficulties in setting standards as in the manufacturing industry since laboratory environments and the types of experiments performed are all different. For these reasons, the measurement of the working environment of research workers is not realistically carried out within the legal framework, there is a concern that the accuracy of measurement results may be degraded, and there are difficulties in securing data. The exposure evaluation based on an eight-hour time-weighted average used for measuring the working environment to be studied in this study may not be appropriate, but it was judged and consequently applied as the most suitable method among the recognized test methods. Methods: The investigation of the use of chemical substances in the research laboratory, which is the subject of this study, was conducted in the order of carrying out work environment measurement, sample analysis, and result analysis. In the case of the use of chemical substances, after organizing the substances to be measured in the working environment, the research workers were asked to write down the status, frequency, and period of use. Work environment measurement and sample analysis were conducted by a recognized test method, and the results were compared with the exposure standards (TWA: time weighted average value) for chemical substances and physical factors. Results: For the substances subject to work environment measurement, the department of chemical engineering was the most exposed, followed by the department of chemistry. This can lead to exposure to a variety of chemicals in departmental laboratories that primarily deal with chemicals, including acetone, hydrogen peroxide, nitric acid, sodium hydroxide, and normal hexane. Hydrogen chloride was measured higher than the average level of domestic work environment measurements. This can suggest that researchers in research activities should also be managed within the work environment measurement system. As a result of a comparison between the professional science and technology service industry and the education service industry, which are the most similar business types to university research laboratories among the domestic work environment measurements provided by the Korea Safety and Health Agency, acetone, dichloromethane, hydrogen peroxide, sodium hydroxide, nitric acid, normal hexane, and hydrogen chloride are items that appear higher than the average level. This can also be expressed as a basis for supporting management within the work environment measurement system. Conclusions: In the case of research activity workers' work environment measurement and management, specific details can be presented as follows. When changing projects and research, work environment measurement is carried out, and work environment measurement targets and methods are determined by the measurement and analysis method determined by the Ministry of Employment and Labor. The measurement results and exposure standards apply exposure standards for chemical substances and physical factors by the Ministry of Employment and Labor. Implementation costs include safety management expenses and submission of improvement plans when exposure standards are exceeded. The results of this study were presented only for the measurement of the working environment among the minimum health management measures for research workers, but it is necessary to prepare a system to improve the level of safety and health.