• Title/Summary/Keyword: 증기운

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Evaluation of Blast Pressure Generated by an Explosion of Explosive Material (폭발성 물질의 폭발에 따른 폭발압력 평가)

  • Yoon, Yong-Kyun
    • Explosives and Blasting
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    • v.36 no.4
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    • pp.26-34
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    • 2018
  • Explosions of vapor cloud formed due to the leakage from installations with flammable fuels have often occurred in Korea and foreign countries. In this study, TNT equivalency method and Multi-Energy method for vapor cloud explosion blast modelling are described and demonstrated in a case study. As TNT equivalency method is simple and direct, it has been widely used for modelling a vapor cloud explosion blast. But TNT equivalency method found to be difficult to select a proper correlation between the amount of combustion energy produced from the vapor cloud explosion and the equivalent amount of TNT to model its blast effects. Multi-Energy method assumes that the strength of vapor cloud explosion blast depends on the layout of the space where the vapor cloud is spreading. Strictly speaking, the explosive potential of a vapor cloud is dependent upon the density of the obstructed regions. In this study, Flixborough accident are analyzed as a case study to assess the applicability of TNT equivalency method and Multi-Energy method. TNT equivalency method and Multi-Energy method found to be applicable if coefficient of TNT equivalency and coefficient of strength of explosion blast are selected properly.

An Availability Assessment of Protection Wall Installed in LPG Filling Station (LPG 충전소 내 설치된 방호벽의 효용성 평가)

  • Lee, Jin-Han;Jo, Young-Do;Moon, Jong-Sam;Kim, Lae Hyun
    • Journal of the Korean Institute of Gas
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    • v.22 no.5
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    • pp.38-45
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    • 2018
  • Jet fire, pool fire, and vapor cloud explosion are major accident scenarios in LPG filling station. The protection wall would mitigate radiation effect in a jet fire. In case of a pool fire, the protection wall would restrict expanding the pool area. The protection wall might both obstruct the dispersion of released vapor and protect blast overpressure in a vapor cloud explosion scenario. In this paper, An availability assessment method of the protection wall how much reduce damage to receptors is proposed. Additionally application cases are presented for the effectiveness of protection wall in the LPG filling station. The study shows that the protection wall can effectively reduce the death probabilities of receptors located behind the wall in cases of the jet fires and the vapor cloud explosions.

Study on the Calculation of the Blast Pressure of Vapor Cloud Explosions by Analyzing Plant Explosion Cases (플랜트 폭발 사례 분석을 통한 증기운 폭발의 폭압 산정법 연구)

  • Lee, Seung-Hoon;Kim, Han-Soo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.34 no.1
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    • pp.1-8
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    • 2021
  • Vapor cloud explosions show different characteristics from that caused by ordinary TNT explosives and their loading effect is similar to pressure waves. Typical methods used for blast pressure calculations are the TNT-equivalent method and multi-energy method. The TNT-equivalent method is based on shock waves, similar to a detonation phenomenon, and multi-energy method is based on pressure waves, similar to a deflagration phenomenon. This study was conducted to derive an appropriate blast pressure by applying various plant explosion cases. SDOF analysis and nonlinear dynamic analysis were performed to compare the degree of deformation and damage of the selected structural members for the explosion cases. The results indicated that the multi-energy method was more exact than the TNT-equivalent method in predicting the blast pressure of vapor cloud explosions. The blast pressure of vapor cloud explosion in plants can be more accurately calculated by assuming the charge strength of multi-energy method as 7 or 8.

Improvement of Charge Strength Guideline for Multi-Energy Method by Comparing Vapor Cloud Explosion Cases (증기운 폭발 사례 비교를 통한 멀티에너지법의 폭발강도계수 지침 개선)

  • Lee, Seung-Hoon;Kim, Han-Soo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.34 no.6
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    • pp.355-362
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    • 2021
  • Various blast pressure calculation methods have been developed for predicting the explosion pressure of vapor cloud explosions. Empirical methods include the TNT equivalent method, and multi-energy method. The multi-energy method uses a charge strength that considers environmental factors. Although the Kinsella guideline was provided to determine the charge strength, there are limitations such as guidelines related to ignition sources. In this study, we proposed an improved charge strength guideline, by subdividing the ignition source intensity and expanding the type classification through literature analysis. To verify the improved charge strength guideline, and to compare it with the result obtained using the Kinsella guideline, four vapor cloud explosion cases which could be used to estimate the actual blast pressure were investigated. As a result, it was confirmed that the Kinsella guidelines showed an inaccurate, that is, wider pressure than the actual estimated blast pressure. However, the improved charge strength guideline enabled the selection of the intensity of the ignition source, and more subdivided types through the expansion of classification, hence it was possible to calculate the blast pressure relatively close to that of the actual case.

Analysis of the Damaged Range Caused by LPG Leakage and Vapor Clouds Considering the Cold Air Flow (찬공기 흐름을 고려한 LPG 누출 및 증기운에 의한 피해 영향 범위 분석)

  • Gu, Yun-Jeong;Song, Bonggeun;Lee, Wonhee;Song, Byunghun;Shin, Junho
    • Journal of the Korean Institute of Gas
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    • v.26 no.4
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    • pp.27-35
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    • 2022
  • When LPG leaks from the storage tank, the gas try to sink to the ground because LPG is heavier than air. The gas easily creates vapor clouds causing aggressive accidents in no airflow. Therefore, It is important to prevent in advance by analyzing the damaged range caused from LPG leakage and vapor clouds. So, this study analyzed the range of damaged by LPG leakage and vapor clouds with consideration of the cold air flow which is generated by the topographical characteristics and the land use status at night time in the Jeju Hagari. As a result of the cold air flow using KLAM_21, about 2 m/s of cold air was introduced in from the southeast due to the influence of the terrain. The range of damaged by LPG leakage and vapor cloud was analyzed using ALOHA. When the leak hole size is 10 cm at the wind speed of 2 m/s, the range corresponding to LEL 60 % (12,600 ppm) was 61 m which range is expected to influence in nearby residential areas. These results of this study can be used as basic data to prepare preventive measures of accidents caused by vapor cloud. Forward, it is necessary to apply CFD modeling such as FLACS to check the vapor cloud formation due to LPG leakage in a relatively narrow area and to check the cause analysis.

Assessment of the Applicability of Vapor Cloud Explosion Prediction Models (증기운 폭발 예측 모델의 적용성 평가)

  • Yoon, Yong-Kyun
    • Explosives and Blasting
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    • v.40 no.3
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    • pp.44-53
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    • 2022
  • This study evaluates the applicability of the TNT Equivalency Method, Multi-Energy Method, and Baker-Strehlow-Tang (BST) Method, which are blast prediction models used to determine the overpressure of blast wave generated from vapor cloud explosion. It is assumed that the propane leaked from a propane storage container with a capacity of 2000 kg installed in an area where studio houses and shopping centers are concentrated causes a vapor cloud explosion. The equivalent mass of TNT calculated by applying the TNT Equivalency Method is found to be 4061 kg. Change of overpressure with the distance obtained by the TNT Equivalency Method, Multi-Energy Method, and BST Method is rapid and the magnitude of overpressure obtained by the TNT Equivalency Method and BST method is generally similar within 100 m from explosion center. As a result of comparing the overpressure observed in the actual vapor cloud explosion case with the overpressure obtained by applying the TNT Equivalent Method, Multi-Energy Method, and BST Method, the BST Method is found to be the best fit. As a result of comparing the overpressure with the distance obtained by each explosion prediction model with the damage criteria for structure, it is estimated that the structure located within 90 m from explosion center would suffer a damage more than partial destruction, and glass panes of the structure separated by 600 m would be fractured.

A Review of the Different Models for Predicting Blast Overpressures Caused by Vapor Cloud Explosions (증기운 폭발에 의해 발생된 폭풍 과압 예측 모델 검토)

  • Park Dal Jae;Lee Young Soon;Lim Young Hoon
    • Journal of the Korean Institute of Gas
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    • v.4 no.4 s.12
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    • pp.50-57
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    • 2000
  • Past accidents have shown that vapor cloud explosions are the predominant cause of the largest losses in the chemical and petrochemical industries due to the generation of significant overpressures. Prediction of such overpressure is of great concern and a knowledge of the likely overpressure is needed for the design of equipment, safety cases and emergency planning. For these reasons, risk assessment for vapor cloud explosion is crucial and this assessment can be carried out using the different models including TNT-Equivalency, TNO Hemispherical, TNO Multi-Energy and CFD models. Accordingly, in this paper, the published VCE prediction models are reviewed to provide a critical comparison of the different models used for the quantification of explosion hazards, in terms of the fundamental assumptions employed, and their predictive accuracy

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A Study on the decision of Scattering distance by Shape of Fragments in LPG Tank lorry Explosion (LPG 탱크로리 폭발시 파편 형상에 따른 비산거리 산정에 관한 연구)

  • Lee, Young Jin;Hwang, Yong Woo;Lee, Ik Mo;Moon, Jin Young
    • Journal of Korean Society of Disaster and Security
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    • v.10 no.2
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    • pp.29-34
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    • 2017
  • LPG is a substance that requires a lot of attention because it can cause fatal damage to people and environment when an accident occurs. LPG is frequently accidents in transportation facilities as well as fixed facilities, among which LPG tank lorries are the most frequent accidents. When the LPG tank is evacuated, the LP gas leaks into two phases, leaks mostly to the gas and leaks to some liquid. At this time, the leaked gas will also sink downward because it is heavier than air, and if it continues to leak, it may form an explosion and explode by the ignition source. The purpose of this study is to present the evacuation distance by analyzing the effect distance of the LPG liquefied petroleum gas in the event of explosion. As a result of calculation of the scattering radius of the fragment, the cylinder fragment was scattered up to 561 m. Therefore, it is appropriate to set the distance to be escaped when the LPG tanker leaks to 561m or more.

Development of Design Blast Load Model according to Probabilistic Explosion Risk in Industrial Facilities (플랜트 시설물의 확률론적 폭발 위험도에 따른 설계폭발하중 모델 개발)

  • Seung-Hoon Lee;Bo-Young Choi;Han-Soo Kim
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.37 no.1
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    • pp.1-8
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    • 2024
  • This paper employs stochastic processing techniques to analyze explosion risks in plant facilities based on explosion return periods. Release probability is calculated using data from the Health and Safety Executive (HSE), along with annual leakage frequency per plant provided by DNV. Ignition probability, derived from various researchers' findings, is then considered to calculate the explosion return period based on the release quantity. The explosion risk is assessed by examining the volume, radius, and blast load of the vapor cloud, taking into account the calculated explosion return period. The reference distance for the design blast load model is determined by comparing and analyzing the vapor cloud radius according to the return period, historical vapor cloud explosion cases, and blast-resistant design guidelines. Utilizing the multi-energy method, the blast load range corresponding to the explosion return period is presented. The proposed return period serves as a standard for the design blast load model, established through a comparative analysis of vapor cloud explosion cases and blast-resistant design guidelines. The outcomes of this study contribute to the development of a performance-based blast-resistant design framework for plant facilities.