• 한국안전학회지
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• 제38권3호
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• pp.43-50
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• 2023

Silicone tetrachloride (SiCl₄) leak accidents cause enormous human and environmental damage because it is highly toxic. Some handling facilities use water curtains to reduce the impact range of SiCl₄. Although the water curtain is known as one of the most efficient technologies for post-release mitigation, its effect on reducing SiCl₄ concentration needs to be investigated scientifically and quantitatively. In this study, three-dimensional computational fluid dynamics (CFD) was used to investigate the physical and chemical effects of water curtains as a release-mitigation system for SiCl₄. SiCl₄ is released and dispersed five seconds prior to the operation of the water curtain. Once the water curtain works, the SiCl₄ reacts chemically with the water and its concentration decreases rapidly; it reaches an emergency response planning guidelines level 2 (ERPG-2) of 5 parts per million (ppm) at about 570 m. We observed, however, that the physical effect of water curtains on reducing SiCl₄ concentration is insignificant when the chemical effect is eliminated. These results are crucial since they can be a scientific and quantitative basis for the 'technical guidelines for estimating the accident affected range'. In order to protect the public from chemical accidents, more toxic gas mitigation technologies need to be developed.

• 한국가스학회지
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• 제27권2호
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• pp.32-38
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• 2023

수도권 내 화학공장에서 부식성 유체를 펌프로 저장탱크에 공급하던 도중 수위파악이 정확히 되지 않아 상부 배기벤트로 부식성유체가 누출되는 사고가 발생하였다. 누출 사고가 발생한데는 다양한 원인이 있지만 직접 원인인 레벨게이지의 수위 지시계가 고착되는 것에 초점을 맞추었다. 분석 결과 사고가 발생한 사업장에서 사용되는 수위 지시계를 임의로 교체하였으며, 사고발생인 여름에 Tubular 방식의 레벨게이지는 열팽창이 쉽게 일어나서 다른 형태보다 고착이 발생될 수 있는 것으로 파악되었다. 또한 국내에는 저장탱크에 설치되는 계측기기의 설치기준이 명확치 않아 적정설치 검토에 어려움이 있었다. 따라서 본 연구에서는 사고사례 및 해외기준을 바탕으로 저장탱크 계측기기류 설치 시 유의사항에 대해 검토하였다.

• 한국습지학회지
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• 제17권1호
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• pp.45-52
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• 2015

구미의 화학약품 제조업체 휴브글로브에서 불산 유출사고가 발생하고 약 1년 후인 2013년 8월 초 사고 발생 현장 주변에 성립한 식생 피해에 대한 조사를 통해 다음과 같은 결과를 얻었다. 소나무와 스트로브잣나무는 매우 심한 피해, 은행나무, 상수리나무, 리기다소나무, 왕버들, 무궁화 및 배롱나무는 심한 피해, 굴참나무, 참싸리 및 참억새는 중간수준의 피해 그리고 갈참나무, 청미래덩굴, 새, 아까시나무 및 오동은 가벼운 피해를 나타내었다. 우리는 피해 현장 주변에서 피해를 입지 않은 어떤 식물도 발견하지 못하였다. 이러한 결과는 불소가 대기, 토양 및 물에 오랫동안 남아 생태계의 모든 수준에 걸쳐 부정적인 영향을 미친다고 알려졌듯이 이 지역에서 지난 해 발생한 불소피해가 여전히 지속되고 있다는 것을 의미한다. 한편, 여천공업단지에서 조사된 결과에 의하면, 식물 잎에 포함된 불소 농도는 비료공장으로부터 거리에 따라 달라졌고 식생 피해는 그 농도에 비례하는 경향이었다. 이런 점에서 불산 유출사고 현장 주변 생태계에 잔존하는 불소의 제거 및 해독 대책이 시급히 요청되고 있다. 불소를 불활성화 시킬 수 있는 칼슘과 마그네슘을 함유하고 있는 돌로마이트의 시비가 그 피해를 완화시킬 수 있는 복원계획의 하나로 준비되었다. 그밖에 토양개량 효과를 증진시키기 위해 인산염 비료 시비가 복원계획으로 추가되었다. 나아가 우리는 불소피해를 완화시키기 위한 두 번째 대책으로 내성종의 도입을 추천하였다. 불소가스 피해로 고사된 나무들을 대체하여 새로운 숲을 만들기 위한 내성종으로 우리는 갈참나무를 추천하였고, 그 숲이 안정된 내부 환경을 확보하기 위한 망토군락을 이룰 식물 종으로는 청미래덩굴과 새를 추천하였다.

• Journal of Advanced Research in Ocean Engineering
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• 제3권1호
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• pp.1-14
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• 2017

The safety analysis of an earthquake is carried out during the operation of a subsea pipeline and an onshore pipeline. Several cases are proposed for consideration. In the case of a buried pipeline, permanent ground deformation by the earthquake and an increase of internal pressure by the acceleration of the earthquake should be considered. In the case of a subsea pipeline, a bending moment is caused by liquefaction of the backfill material on a trenched seabed, etc., which results in a high bending moment of the buried pipeline. The bending moment causes the collapse of the subsea pipeline or a leak of crude oil or gas, which results in economic loss due to enormous environmental contamination and social economic loss owing to operation functional failure. Thus, in order to prevent economic loss and operation loss, structurally sensitive design with regard to seismic characteristics must be performed in the buried pipeline in advance, and the negative impact on the buried pipeline must be minimized by conducting a thorough analysis on the seabed and backfilling material selection. Moreover, it is proposed to consider the selection of material properties for the buried pipeline. A more economical review is also required for detailed study.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2000년도 춘계학술대회 논문집(Proceeding of the KOSME 2000 Spring Annual Meeting)
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• pp.115-121
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• 2000

As the development of industry water quality of river is going to bad because of waste water of an industrial complex and general home agricultural chemicals exhaust of $SO_3$ and CO gas acid rain and so on. Corrosion damage of boiler factory equipment and so forth occur quickly due to using of the polluted water resulting in increasing leak accident. Especially working life of hot water boiler using the polluted water becomes more short and energy loss increases. The cathodic protection method is the most economical and reliable one to prevent corrosion damage of steel structures. Mg-base alloys galvanic anode protection of cathodic protection method is suitable for than application of hot water boiler using water with high specific resistance such as tap water. This paper is studied on the cathodic protection characteristics of how water boiler. In tap water and 0.001mol/$\ell$ NaCl solution the characteristics of anodic polarization of Mg-base alloys galvanic anode and tube material is investigated the measurement of cathodic protection potential according to the time elaspsed is carried out.

• 한국기계가공학회지
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• 제10권3호
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• pp.39-46
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• 2011

The automotive air conditioning hose is used for connecting the components of air conditioner in a vehicle. The hose is usually manufactured by the swaging process to connect the rubber hose with the metal fitting at the end of the hose. In case that the clamping force is small, the refrigerant gas in the hose can leak locally under the severe operating circumstances. The practical test of clamping force is performed by means of the measurement of separation force. In this study, the swaging process of a hose is simulated with the finite element method, to investigate the effect of friction coefficient on the clamping force. The contact condition is used in consideration of real manufacturing process, and the material properties for the Mooney-Rivlin model is obtained by the experimental results. The result interpretations are focused on the contact forces, which is displayed graphically with respect to friction coefficient, on the surfaces between the hose and the metal fittings.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2007년도 춘계학술발표회 논문집
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• pp.180-185
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• 2007

Likelihood analysis was used for the revision of release probability/frequency in chlorine Injection facilities used in chlorine process. Typically these facilities consist of pressure cylinder, vaporizer, pipeline, measuring equipment and safety equipment. This paper described the incident scenarios considered, likelihood analysis procedure and the selection and application of basic events and for failure rates of mechanical components. Human errors were also considered. The major objective of this paper is to estimate the likelihood of each determined incident scenarios. We estimated failure rates of mechanical components based on likelihood analysis procedure. Human errors were also considered. It was estimated to have $5.73{\times}10^{-5}\;Cl_2$ leak per year during the major $Cl_2$ handling process. The probability of failure in scrubber system was $4.11{\times}10^{-2}/demand$.

• 산업공학
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• 제24권3호
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• pp.187-195
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• 2011

The automatic radiopharmaceutical module consists of several 2-way valves, couple of syringes, gas supply unit, heating(cooling) unit and sensors to control the chemical reagents as well as to help the chemical reaction. In order to control the actuators of radiopharmaceutical module, the process is tabulated using spread sheet as like excel. Unlike the common program, a trivial error is too critical to allowed in the process because the error can lead to leak the radioactive reagent and to cause the synthesis equipment failure during synthesizing. Hence, the synthesis process has been validated using graphic simulation while the operator checks the whole process visually and undergoes trial and error. The verification of the synthesis process takes a long time and has a difficulty in finding the error. This study presents a methodology to verify the process algebraically while the radiopharmaceutical module is converted to the network model. The proposed method is validated using actual synthesis process.

• 한국유기농업학회지
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• 제23권4호
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• pp.643-658
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• 2015

This study presents detailed emission of greenhouse gases of using Clean Energy Agriculture System according to a cradle-to-gate life-cycle assessment, including emission from energy use and leak of Biogas. Calculations were done with the PASS software and the covered gases are $CH_4$, $N_2O$ and $CO_2$, Total GHG fluxes of amount to $1719.03kgCO_2/day$, $39.63kgCO_2/day$ (2.31%) are from facility house process, $0.19kgCO_2/day$ (0.01%) are from transport process, $696.72kgCO_2/day$ (40.53%) are from Anaerobic digestion process, $846.61kgCO_2/day$ (49.25%) are from Heating and cooling system, $135.88kgCO_2/day$ (7.90%) are from Fertigation production process. The results suggest that for effective reduction of GHG emissions from Facility house using clean energy. Reduction targets should address both the production process as defined by IPCC sectors and the consumption process. An LCA assessment as presented here could be a basis for such efforts.

• 한국주거학회논문집
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• 제26권5호
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• pp.79-87
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• 2015

This study explored low-income households' experiences and perception of home energy cost burdens and determinants of the perceived home energy cost burdens. Between March and July 2014, a questionnaire survey was administered in Cheongju, South Korea. Among the 434 useable responses collected, responses from 218 households with monthly income less than 2,500,000 Korean Won (KRW) were compared with those of 216 households with higher incomes. The main findings are as follows. In the past three years, more than 10 percent of low-income households had had their electricity cut off; 5.7 percent had had their city gas cut off. To pay for their home energy expenses, nearly 70 percent of the low-income households had had to limit their heating, cooling or spending for other necessities; 38.3 percent had to borrow money. Low-income households reported more problems paying for home energy than higher-income households did. Households with more negative evaluation of rainwater leak, no one staying at home all day, monthly income less than 1,500,000 KRW and householders in their 40s and 50s tended to perceive a heavier home energy cost burden. Finally, the most popular support programs were fuel assistance and discounts on energy bills.