• Title/Summary/Keyword: Explosion hazards

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Qualitative Hazard Analysis for a Batch Radical Reaction Process using HAZOP Method (HAZOP 기법을 이용한 회분식 라디칼 반응 공정에 대한 정성적 위험성 평가 방법 연구)

  • Park, KyungMin;Lee, DongKyu;Lee, JoonMan;Ahn, WonSool
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.2
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    • pp.385-393
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    • 2019
  • Potential fire, explosion and safety hazards exist in medium- or small-scale chemical plants using radical batch reaction processes due to the various conditions of materials, works or products. To minimize the potential damage, a study was conducted on qualitative hazard analysis using the HAZOP technique, which is a typical method for a qualitative risk assessment and analysis of the potential risks encountered in these chemical plants. For this purpose, a domestic chemical plant, which produces the acrylic resin by a radical batch reaction process, was selected and a risk assessment and analysis according to the procedure of HAZOP method was performed for the process. As the result of the study, to prevent the hazard, the input of inert gas and the installation of a pressure gauge were indispensable. In addition, the initiator and monomer should also be separated, and inhibiting substances and equipment are also necessary to prevent a runaway reaction.

A Study on the Ground Vibration Reduction Characteristics of Air-Deck Blasting Method Using Paraffin Waxed Paper Tube (파라핀 지관 구조체를 활용한 Air-Deck 발파공법의 지반진동 저감특성에 관한 연구)

  • Gyeong-Jo, Min;Young-Keun, Kim;Chan-Hwi, Shin;Sang-Ho, Cho
    • Explosives and Blasting
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    • v.41 no.1
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    • pp.32-45
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    • 2023
  • Environmental regulations in Korea for blasting at industrial sites have conservative standards, which often result in reduced efficiency and cost-effectiveness due to the consideration of environmental regulations and public complaints. Therefore, there is a need for blasting methods that can reduce environmental damage while improving construction efficiency and cost-effectiveness. In this study, we analyzed the effects of the PA-Deck (Paraffin Air-Deck) blasting method, which is a kind of Air Decoupled Charge method in principle utilizing a paraffin-infused paper tube as an air gap, on reducing blasting hazards and improving blasting efficiency. The analysis also evaluated the effectiveness of newly applied equipment for collecting blasting vibration data, and derived the relationship between the explosion velocity and vibration velocity of explosives, and performed frequency analysis of the vertical component. The results of the blasting vibration velocity analysis showed that the Paraffin Waxed Paper Tube-based blasting method exhibited significantly lower vibration velocities compared to conventional blasting methods, and it was judged that more uniformly small-sized fragmented rocks were generated.

Impact Resistance Characteristics of Cementitious Composites Subjected to High-velocity Projectiles with Reinforcement Types (고속 발사체와 충돌한 시멘트복합체의 보강재 종류에 따른 내충격 특성 연구)

  • Seok, Won-Kyun;Kim, Young-Sun;Lee, Yae-Chan;Nam, Jeong-Soo;Kim, Gyu-Yong
    • Journal of the Korea Institute of Building Construction
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    • v.23 no.3
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    • pp.261-272
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    • 2023
  • This research concentrates on the potential explosion hazards that could arise from unforeseen accidents in the rapidly proliferating hydrogen refueling stations and Energy Storage System(ESS) facilities. It underscores the pivotal role of structural protection technology in alleviating such risks. The research contributes primary data for the formulation of structure protection design by assessing the impact resistance across various reinforcement techniques used in cement composites. The experimental results elucidate that reinforced concrete, serving as the quintessential structural material, exhibits a 20% advancement in impact resistance in comparison to its non-reinforced counterpart. In situations typified by rapid loads, such as those seen with high-velocity impacts, the reinforcement of the matrix with fibers is demonstrably more beneficial than local reinforcement. These insights accentuate the importance of judiciously choosing the reinforcement method to augment impact resistance in structural design.

A Study on Quantitative Risk Analysis & Model Application for Hydrogen Filling Center (수소충전시설에 대한 정량적 위험성 평가 및 모델적용에 관한 연구)

  • Shin, Jung-Soo;Byun, Hun-Soo
    • Journal of the Korean Institute of Gas
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    • v.16 no.6
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    • pp.87-101
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    • 2012
  • In gas industries, the potential risks of serious accidents have been increased due to high technology application and process complexities. Especially, in case of gas-related accidents, the extent of demage is out of control since gas plants handle and produce combustible, flammable, explosive and toxic materials in large amounts. The characteristics of this kind of disaster is that accident frequency is low, while the impact of damage is high, extending to the neighboring residents, environment and related industries as well as employees involved. The hydrogen gases treated important things and it used the basic material of chemical plants and industries. Since 2000, this gas stood in the spotlight the substitution energy for reduction of the global warming in particular however it need to compress high pressure(more than 150 bar.g) and store by using the special cylinders due to their low molecular weight. And this gas led to many times the fire and explosion due to leak of it. To reduce these kinds of risks and accidents, it is necessary to improve the new safety management system through a risk management after technically evaluating potential hazards in this process. This study is to carry out the quantitative risk assesment for hydrogen filling plant which are very dangerous(fire and explosive) and using a basic materials of general industries. As a results of this risk assessment, identified the elements important for safety(EIS) and suggested the practical management tools and verified the reliability of this risk assessment model through case study of accident.

A Study on Fire Hazards in Multiple Compartments with Lightweight Partition Walls (경량칸막이 벽체를 통한 다중구획공간에서의 화재위험성에 관한 연구)

  • Park, Sang-Min;Choi, Su-Gil;Jin, Se-Young;Kim, Si-Kuk
    • Fire Science and Engineering
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    • v.34 no.2
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    • pp.14-21
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    • 2020
  • This paper presents the study of a fire risk to the backside of two miniatures of ISO 9705 2/5 using a lightweight partition for indoor space division and reproduction of the ISO 9705 test. An SGP partition, stud partition, glass wool panel, urethane foam panel, sandwich panel, and glass partition were selected as the test specimens, which are frequently used in construction. According to the ISO 9705 test standard, stabilization was achieved using a measuring device that recorded data before the ignition of a burner and continued recording for 120 s thereafter. After ignition was achieved, the power was increased to 300 kW for 600 s and then reduced to 100 kW for 600 s. The specimens were subsequently observed for 180 s, and the fire risk to the backside and the fire pattern of the wall unit were analyzed. Owing to the amount of heat generated by the ignition source, the maximum temperature of the backside was observed to be 67.7 ℃ for the SGP partition, 55.1 ℃ for the stud partition, 52.4 ℃ for the glass wool panel, 727.4 ℃ for the sandwich panel, 561 ℃ for the urethane foam panel, and 630.5 ℃ for the glass partition. In the cases of the sandwich and urethane foam panels, the explosion of flammable gas occurred by virtue of fusion of the interior materials. The reinforced glass was fractured owing to the temperature difference between the heat- and nonheat-responsive parts. Ultimately, the fire risk to the nearby section room was deemed to be high.

Study on the Current Safety Management Status and Safety Improvement of Gas Valve (가스밸브의 안전관리 현황 및 안전성 향상 연구 (모니터링을 중심으로))

  • Choe, Byeong-Gyu;Cha, Min-Chang;Kim, Jin-Jun
    • Journal of the Korean Institute of Gas
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    • v.20 no.5
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    • pp.57-63
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    • 2016
  • Though a valve is a very important part in a system to control properly, it has potential failure caused by gap from valve stem to ball connection, and abrasion, crack, fixation causing operational trouble and accidents. 64% of the valve failure in the real case was the failure of airtightness and most accidents of leakage and explosion were occurred while fixing the failure. While there are no proper safety manual, maintenance procedure and regulation for industrial valves excluding safety valve, safety management for the valves is left to the discretion of the maintenance company. Strict maintenance that removes hazards and emergency response procedure are required to prevent and reduce the loss of accident. This study suggests safety enhancement measures through valve monitoring by investigating the status of use of valve and current maintenance. Enhancement of gas safety management can be acquired by a monitoring system that provides diagnosis for valve status, monitoring real-time gas leakage, management of entire cycle lifetime that can reduce maintenance cost.

Problems on Pesticide Safe-Use and Their Counter-Measures (농약안전사용상의 문제점과 그 대책)

  • Han Ki-Hak
    • Korean journal of applied entomology
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    • v.22 no.2 s.55
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    • pp.138-146
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    • 1983
  • With the increase of pesticide consumption, not only pesticide handling population would grow greater but also the chances to be exposed to the pesticides would be also increased. Thus, safe use and handling of the pesticides are becoming more important and serious in these days. The pesticides are well known to most pepole, however there are very limited number of persons who have correct understanding of chamicals. Intoxication cases caused by pesticides have been reported very rarely through the mess media, even they were lack of scientific evidences. In this paper, problems related to pesticide manufacture, transportation, storage, sprays, and residues and their countermeasures were discussed in connection with public health and enviromental aspects. Acute intoxication cases by pesticide handling might be caused accidently either through manufacture, marketing, transportation, or spraying. Safety aspects of workers in manufacturing plants include not only exposure to toxic chemicals, but also posibilities of of explosion and brought about by pesticides and their diluents. The problems of water pollution by waste chemicals from the manufacturing factories were discussed. Packing and loading methods of pesticides for transportation are considered in safety scheme and discussions are given in association with traffic accidents. With regard to warehouse, the pesticide storage, location structure, keepers, and standing materials for emergency are concerned with safety aspects. Concerning the spraying of chemicals, there are some problems to be discussed about clothes, spray equipment, wind direction, spray period, and spray workers condition. After the spray, treatment of used containers, remainder of Pesticides, and spray tools are also discussed. For the dissolutions of problems on public health and environmental danger arising from pesticide residues, there are two legal sanctions; 'Pesticide Tolerances' and 'Pesticide Safe Use Standards'. These regulations are legally effective, however, some problems still remain in practices to implement the acts properly, because these provisions are followed by the far mers mostly. With these regards, most problems are concerned with various sectors and persons, affecting public health and environment from the producers to the end users and consumers. As a whole persons concerned with pesticides, every possible effort has to be assembled to protect hazards from the chemicals. For the foremost place, special training and education are required for managing groups; such as factory managers and agricultural extension workers who are responsible for training the factory workers and farmers. The education is the only way to solve the hazard problems caused by the pesticides.

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Exposure Assessment of Hazardous gases in Confined Spaces (밀폐공간 종류별 유해가스 발생 농도 평가)

  • Park, Hyunhee;Yoo, Kye-mook;Ham, Seung-hon;Chung, Kwang-Jae;Shin, Min-a;Lee, Koo-yong;Jang, Kyung-jo;Yoon, Chung-sik
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.19 no.4
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    • pp.381-389
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    • 2009
  • Confined spaces are inherently dangerous workplace and many fatal and nonfatal accidents have been reported. Even though these accidents occur in various kinds of confined spaces, there has rarely been reported on the health hazard agent, i.e., the types of gases and their concentration ranges. Therefore in this study, we evaluated several toxic and asphyxiating gas concentrations in various confined spaces. We surveyed 57 manholes, 3 sewage treatment plants, 2 yellow radish manufacturing companies and 7 barges to measure the concentrations of oxygen($O_2$), hydrogen sulfide($H_2S$), carbon monoxide(CO), ammonia($NH_3$). Lower Explosion Limits(LEL) and Volatile Organic Compounds (VOCs). Those four types of confined spaces occupies 56% of accidents during last 9 years in Korea. In 57 manholes, the concentration varied according to the types of manholes; rainfall and sewage, and by location; residential and industrial areas. Sewage manhole in industrial area was evaluated as the most hazardous than other types of manhole like rainfall manholes, residential sewage manholes. The highest $H_2S$ concentration and the lowest $O_2$ concentration at sewage manhole in industrial area were 300 ppm, 8.7% respectively. In 3 sewage treatment plants, $H_2S$ and $NH_3$ concentrations were reached up to the 500 ppm and 200 ppm respectively. Two yellow radish manufacturing companies showed the concentrations of 316 ppm, 505.2 ppm, 90 ppm and 15.7% for $H_2S$, CO, VOCs and $O_2$, respectively. Seven barges showed 15.9%~20.9% oxygen concentration. Gas species and concentration ranges varied by the types and location of confined spaces; CO, $H_2S$, $O_2$ could be hazardous in manhole, especially manhole connected to sewage plants. CO, $H_2S$, LEL, $O_2$, $NH_3$ should be controlled in sludge silo and sluge pumping confined spaces in sewage treatment plant. The activity of lifting out radish from the storage tank was evaluated more hazardous rather than the other activities in yellow radish manufacturing industry. The employers must conduct the survey to identify all possible confined spaces in their local workplace prior to performing the tasks. At the national level to reduce the accidents in the confined spaces, we suggest that systemic approach and active education program including possible hazards, standard operation procedures, ventilation plan, and personal protective equipment in confined spaces should be implemented.

Comparison of Partial Least Squares and Support Vector Machine for the Flash Point Prediction of Organic Compounds (유기물의 인화점 예측을 위한 부분최소자승법과 SVM의 비교)

  • Lee, Chang Jun;Ko, Jae Wook;Lee, Gibaek
    • Korean Chemical Engineering Research
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    • v.48 no.6
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    • pp.717-724
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    • 2010
  • The flash point is one of the most important physical properties used to determine the potential for fire and explosion hazards of flammable liquids. Despite the needs of the experimental flash point data for the design and construction of chemical plants, there is often a significant gap between the demands for the data and their availability. This study have built and compared two models of partial least squares(PLS) and support vector machine(SVM) to predict the experimental flash points of 893 organic compounds out of DIPPR 801. As the independent variables of the models, 65 functional groups were chosen based on the group contribution method that was oriented from the assumption that each fragment of a molecule contributes a certain amount to the value of its physical property, and the logarithm of molecular weight was added. The prediction errors calculated from cross-validation were employed to determine the optimal parameters of two models. And, an optimization technique should be used to get three parameters of SVM model. This work adopted particle swarm optimization that is one of heuristic optimization methods. As the selection of training data can affect the prediction performance, 100 data sets of randomly selected data were generated and tested. The PLS and SVM results of the average absolute errors for the whole data range from 13.86 K to 14.55 K and 7.44 K to 10.26 K, respectively, indicating that the predictive ability of the SVM is much superior than PLS.

A Case Study on the TEMAZ Explosion Accident in Semiconductor Process (반도체 공정에서 TEMAZ폭발사고 사례연구)

  • Yang, Won-Baek;Rhim, Jong-Kuk;Hong, Seong-Min
    • Journal of the Korean Institute of Gas
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    • v.21 no.6
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    • pp.52-60
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    • 2017
  • In diffusion process exhaust line during semiconductor manufacturing process, In order to improve the transportation efficiency in the piping by removing "The reaction by-product, $ZrO_2$ and The unreacted material, TEMAZ, TMA, $O_3$, etc" and "Powder being deposited", the piping temperature was raised to $80^{\circ}C$ or more by using the heater jacket, and the bellows at the rear end of the vacuum pump ruptured. So conducted a case study and try to prevent the similar accidents from occurring through case studies. The causes of the accident were analyzed as follows: the inflow of outside air due to the generation of a gap on the suction side of the vacuum pump and heating the pipe with the heater jacket resulted in the overpressure in the pipe due to the volumetric expansion of the gas generated by decomposition of the unreacted TEMAZ, It can be assumed that the most vulnerable bellows of the piping has been ruptured. In order to prevent such accidents, This study is aimed to identify the cause of pipeline rupture accident and to establish safety measures for the prevention of similar accidents by evaluating physical hazards of TEMAZ, which is assumed to be the cause of pipe rupture accident.