• 한국환경보건학회지
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• 제47권2호
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• pp.175-181
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• 2021

Objectives: The correlation between the size of a leak hole, the volume of the leakage, and the range of influence was investigated for a hydrochloric acid tank-lorry. Methods: For the case of a tank-lorry chemical accident, KORA (Korea Off-site Risk Assessment Supporting Tool) was used to predict the leak rate and the range of influence according to the size of the leak hole. The correlation was studied using R. Results: As a result of analyzing the leak rate change according to the leak hole size in a 35% hydrochloric acid tank-lorry, as the size of the leak hole increased from 1 to 100 mm, the leak rate increased from 0.008 to 83.94 kg/sec, following the power function. As a result of calculating the range of influence under conditions ranging from 1 to 100 mm in size and 10 to 60 minutes of leakage time, it was found that the range spanned from a minimum of 5.4 m to a maximum of 307.9 m. As a result of multiple regression analysis using R, the quadratic function model best explained the correlation between the size of the leak hole, the leak time, and the range of influence with an adjected coefficient of determination of 0.97 and a root mean square error of 22.33. Conclusion: If a correlation database for the size of a leak hole is accumulated for various substances and under various conditions, the amount of leakage and the range of influence can easily be calculated, facilitating field response activities.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.170-175
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• 1992

A leak detection method for diagnosis of the leak position in a pipeline was developed using an estimation theory with the assumption that the measured flow rates and pressures are stochastic processes. A notch filter was designed using power spectral density analysis of measurements to reduce the effects of disturbances. The noise model dimension was determined by hypothesis testing and then recursive extended least square method was applied to estimate the leak position in real time. The proposed method was applied to an experimental system for evaluation of its performance.

• 한국가스학회지
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• 제23권2호
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• pp.17-27
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• 2019

화학물질의 사용 증대와 더불어 위험물 및 독성가스 누출 사고가 빈번하게 일어나고 있다. 그 중에서도 위험물 저장설비 사고는 누출이 감지되었을 때 대응하기 위한 초동 조치가 가장 중요하지만, 전적으로 조업자에 의한 경험에 비중이 크기 때문에, 잘못된 판단으로 인한 더 큰 물적, 인적 피해가 발생할 가능성이 높다. 본 연구는 기존 고정식 감지기를 통한 알람 발생 후 수동적인 대응을 취하는 현 접근 방식에서 벗어나, 오픈소스기술을 적용하여 쉽게 제작이 가능한 로봇 플랫폼에서 작동하는 이동식 센서를 활용한 능동적인 누출원 추적 시스템을 설계하였다. 아울러 프로토타입 시스템의 검증을 통해 누출 초기의 정확한 현장 상황파악 및 조기대응을 바탕으로 사고의 확산 및 피해 최소화의 기틀을 마련하고자 하였다.

• 한국재난정보학회 논문집
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• 제20권1호
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• pp.213-221
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• 2024

연구목적: 유해화학물질인 염산수용액 운송 탱크로리 누출사고 발생 시 신속하게 누출을 차단하고, 효과적으로 방재작업을 진행하여 누출로 인한 피해를 최소화하는 최적의 방안을 찾고자 하는 데 있다. 연구방법: 염산에 대한 전반적인 특성과 운송 도중 발생했었던 사고사례를 사고 유형별, 원인별로 정리하고, 염산 탱크로리의 누출 상황을 가정하여 실험할 수 있는 소형 탱크를 만들어 누출 상황과 비슷한 환경을 구성하여 여러 가지 방법으로 누출 차단 방법을 실험하여 정리하고자 한다. 연구결과: 실험을 통하여 효과적인 누출 차단 방법을 확인하였다. 누출사고 발생 시 신속하게 차단하는 방안을 정리하여, 사고현장에서 적용할 수 있는 최적의 방재방안을 제시하고자 한다. 결론: 누출 차단은 접착테이프와 자석을 조합하여 사용하는 편이 차단에 효과적인 것으로 확인됐다. 사업장 비상 출동팀 및 제품 운송기사들에게 누출 차단 장비를 적절하게 선택하여 대응하도록 반복 훈련하면 신속한 대응이 가능하다. 향후 다양한 누출 차단 방안에 관한 추가적인 연구의 진행이 필요하다.

• 한국안전학회지
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• 제37권6호
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• pp.25-31
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• 2022

In this study, the spill and leak system is developed to provide real-time remote monitoring of industrial complexes where chemical accidents have been occurring every year. The spill and leak monitoring system uses IR-RCD equipment mounted on a 70m-high steel tower to detect chemical substances, thereby detecting chemical accidents such as leaks, fires, and explosions in real time. If IR-RCD equipment can actually detect chemical substances at a long distance, accurate and rapid initial response can be expected. Therefore, in order to confirm that IR-RCD equipment can detect chemical leakage accidents occurring at a long distance, acetone was selected as the experimental substance and a detection experiment was designed. The experiment was conducted using the acetone pool evaporation method at the wharf which was located 1.5 km away from IR-RCD equipment, and it was confirmed whether IR-RCD equipment could detect acetone in real time through the control monitor.

• 한국유체기계학회 논문집
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• 제19권4호
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• pp.39-42
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• 2016

A PFA lined ball valve, which is machined with fluorinated resin PFA to its inner part for improving corrosion resistance, non-stickness, heat-resistance, has been widely used to the chemical/pharmaceutical industries, the semiconductor/LCD manufacturing processes, etc. with the high purity chemicals as working fluid. EPA stated that 60% of all fugitive emissions come from the valve stem packing in a typical petroleum or chemical processing plant. They monitor regulated components for leaks and maintain seal performance at acceptable levels. Korean industrial standards only deals with the bubble test for in-line leakage of valves, which has the detectable leak rate of $10^{-4}$ [$mbar{\cdot}L{\cdot}s^{-1}$], therefore, it is not sufficient to check fugitive emissions. In this study, we conducted Helium leak detection from a PFA lined ball valve and evaluated fugitive emissions according to ISO 15848-1, which has the detectable leak rate of $10^{-9}$ [$mbar{\cdot}L{\cdot}s^{-1}$], for manufacturing the high-reliable PFA lined ball valves against fugitive emissions.

• 한국가스학회지
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• 제20권2호
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• pp.66-71
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• 2016

현재 산업단지에는 수많은 센서로부터 얻는 정보를 이용해 누출 발생지역을 감지 감시하고 있다. 그러나 화학물질 누출사고는 꾸준히 발생하고 있으며, 때에 따라 다량의 화학물질이 누출되는 경우에는 큰 피해가 발생하고 있다. 이때 중요하게 작용하는 센서 배치가 현재까지는 과거의 경험을 통하여 그 결정이 이루어지거나, 또는 센서제작 업체에서 제시하는 가이드를 통하여 설치되고 있다. 따라서 본 연구에서는 화학물질 누출이 일어났을 때 빠른 감지 및 대응을 위해 가장 중요한 요소인 센서 배치 최적화 방법론을 제시하였다. 특히 공정구조에 따른 누출흐름이 미반영된 상태에서 초기 배치 최적화를 위해 센서 개수 최소화 측면과 화학물질감지확률 측면으로 나누어 일반적으로 사용할 수 있는 수식을 제시하였다. 제시된 방법은 간단한 누출 시나리오를 이용하여 검증을 진행하였고, 이를 통해 각 공정의 안전성 목표치를 성취함으로써 안전한 공정 운영이 가능하도록 하였다.

• Journal of Chest Surgery
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• 제50권4호
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• pp.281-286
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• 2017

Background: In chemical pleurodesis for managing pulmonary air leak, tetracycline derivatives are commonly used, and their effectiveness has been established in many studies. Recently, a Viscum album extract was used in chemical pleurodesis. We compared the effects of V. album with those of a tetracycline derivative (doxycycline) to demonstrate the therapeutic effectiveness of the V. album extract in chemical pleurodesis for managing pulmonary air leak. Methods: Between October 2010 and October 2016, chemical pleurodesis was performed using doxycycline in 40 patients and the V. album extract in 37 patients. Thirty-three patients were in the postoperative state after pulmonary resection, and 44 patients suffered from spontaneous pneumothorax. Results: No statistically significant difference in the success rate was observed between the 2 groups (V. album extract and doxycycline). In both groups, chest pain was the most common complication. More patients in the doxycycline group complained of severe chest pain (42.1% vs. 13.5%, p=0.006). In the V. album extract group, 24.3% of the patients required a chest tube to drain the pleural effusion after cessation of the air leak (doxycycline group: 5%, p=0.022). Further, the amount of pleural effusion drained on the day after the last chemical pleurodesis in the V. album extract group was greater than that in the doxycycline group ($162.2{\pm}170.2mL$ vs. $97.0{\pm}77.2mL$, p=0.032). All patients were discharged from the hospital without complications after pleural effusion drainage. Conclusion: Considering that treatment using the V. album extract was less painful, V. album might be a feasible option for chemical pleurodesis. However, pleural effusion should be monitored carefully when using V. album extract for treating patients suffering from air leak.

• 한국안전학회지
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• 제32권6호
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• pp.1-8
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• 2017

P-PIE is a program developed to estimate failure probability of pipes and pressure vessels considering fatigue and stress corrosion crack growth. Using the program, crack growth simulation was performed with an initially existing crack in order to examine the effects of initial crack depth distribution on the leak probability of pipes. In the simulation stress corrosion crack growth was considered and several crack depth distribution models were used. From the results it was found that the initial crack depth distribution gives great effect on the leak probability of pipes. The log-normal distribution proposed by Khaleel and Simonen gives lower leak probability compared other exponential distribution models. The effects of the number and the quality of pre-service and in-service inspections on the leak probability were also examined and it was recognized that the number and the quality of pre-service and in-service inspections are also give great effect on the leak probability. In order to reduce the leak probability of pipes in plants it is very important to improve the quality of inspections. When in-service inspection is performed every 10 years and the quality of inspection is above the very good level, the leak probability shows nearly constant value after the first inspection for an initially existing crack.

• 한국수소및신에너지학회논문집
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• 제28권2호
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• pp.166-173
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• 2017

For commercialization of hydrogen refuelling station (HRS), we need to reduce the clearance distance for jet fire in the real entities in the HRS. Thus, we revisited the current regulations of clearance distance for jet fire in the law. The law in korea has been set up by replica of japan, not by our own scientific basis. Recently, sandia lab developed Hydrogen Risk Assessment Model (HyRAM) tools and we simulated a series of circumstances such as 10 to 850 bar with several leak hole sizes. In 850 bar with 10 mm diameter hole leak cases, it shows $4,981kW/m^2$ at 12 m separation from leak source and $1,774kW/m^2$ at 17 m separation from leak source. In 850 bar with 1 mm diameter leak hole, it shows $0.102kW/m^2$ at 12 m separation and $0.044kW/m^2$ at 17 m separation. Current law may be acceptable with 1 mm hole size with 850 bar.