화학사고 피해저감을 위한 GIS 연계 복합시뮬레이션 프로토타입 개발에 관한 연구

김은별,오주연,이태욱,오원규,김현주,임동연 대한원격탐사학회 2020 大韓遠隔探査學會誌 Vol.36 No.5

In this study, a complex simulation prototype was developed for rapid and accurate prediction of chemical dispersion range in order to reduce human casualties caused by chemical accidents. Complex simulation considered the leakage momentum during the near-field dispersion to take into account the leakage characteristics of the chemical. In the far-distance dispersion process, the wind distribution of the existing model, which was presented uniformly, was improved using weather and topographical information around the accident site, to realize a wind field similar to the actual one. Finally, the damage range was more precise than the existing model in line with the improved near- and far-distance dispersion process. Based on the results of damage range prediction of the complex simulation, it is expected that it will be highly utilized as a system to support policy decision-making such as evacuation and return of residents after a chemical accident. 본 연구에서는 화학사고에 따른 인명피해 저감을 위해서 신속하고 정확한 화학물질 확산 범위 예측을위한 복합시뮬레이션 프로토타입을 개발하였다. 복합시뮬레이션은 화학물질의 누출 특성을 고려하고자 근거리 확산과정에서 누출 운동량을 고려하였다. 원거리 확산과정에서는 사고지점 주변의 기상 및 지형정보를 이용하여 획일적으로 제시되었던 기존 모델의 바람 분포를 개선하여 실제와 유사한 바람장을 구현하였다. 개선된 근·원거리 확산과정에 따라 최종적으로 피해확산 범위는 기존의 모델에 비해서 정밀한 분포를 나타냈다. 본연구에서 개발된 복합시뮬레이션의 시간대별 피해 범위 예측 결과 통해서 화학사고 발생 후 주민 대피 및 복귀등 정책적 의사결정의 지원시스템으로서 활용도가 높을 것으로 기대된다.

구조물 형상 변화에 따른 살리실산메틸 확산 유동에 관한 연구

홍창기(Chang-Ki Hong),김윤제(Youn-Jea Kim) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11

In order to predict the chemical agent dispersion in the complex urban area, numerical study on the thermal-flow characteristics in the vicinity of buildings were performed. In particular, methyl salicylate was adopted as chemical similitude agent. Right cylinder, regular hexahedron and regular four side pyramid shapes were applied. Numerical computations were carried out with the commercial code, CFX, which applied the finite volume method to solve the Navier-Stokes equations. With the help of the wind tunnel experiments, empirical formula was derived. The results could be used as the virtual test method of the real chemical agent dispersion.

양쪽성 계면활성제 분산제가 함유된 반도체용 CMP(Chemical mechanical polishing) 세리아 슬러리의 트리에탄아민함량에 따른 안정성 연구

하지성,김운중,양정원 융복합지식학회 2024 융복합지식학회논문지 Vol.12 No.2

CMP(chemical mechanical polishing) 공정은 공정 과정을 거치면서 웨이퍼에 생기는 패턴 단차를 화학 및 물리적 작용을 이용하여 평탄화, 불필요한 박막을 제거하는 공정이다. 양쪽성 계면활성제 구조를 가진 분산제는 CMP 공정 중 중앙 부분과 모서리 부분의 연마율에 큰 변화가 없으나 경시적으로 pH 감소가 나타나며 입자들의 응집이 발생한다. 본 연구에서는 양쪽성이온 분산제를 사용한 슬러리에 트리에탄올아민(Triethanolamine)을 단계적으로 첨가하여 안정성 연구를 진행하였다. pH, conductivity, OM(optical microscope), DLS(dynamic light scattering), viscosity, zeta potential을 이용하여 분산 안정성을 확인하였으며 트리에탄올아민을 첨가한 슬러리의 연마율을 비교 분석하였다. 본 연구 결과, pH는 약 3 정도 낮아졌으며 TEOA (triethanolamine) 첨가 함량이 높을수록 변화 폭이 작고 안정함을 확인하였다. Conductivity 분석 결과 전체적으로 상승하는 결과를 보였고, TEOA 함량이 증가할수록 더 높은 상승폭을 보였다. OM 분석 결과 실온에서는 큰 변화가 없었지만 60℃에 보관한 CMP 슬러리의 경우 입자의 응집을 확인하였으나, TEOA를 첨가한 슬러리는 온도에 관계없이 안정함을 확인했다. Zeta potential 분석 결과 CMP 슬러리에 비해 TEOA를 첨가한 슬러리는 초기와 큰 변화 없이 안정적인 분산성을 나타내었다. DLS 분석 결과 CMP 슬러리는 실온에서 약 160nm, 60℃에서 약 330nm로 입자 사이즈가 증가했지만, TEOA 첨가 슬러리는 초기와 큰 변화 없이 안정함을 확인하였다. Viscosity 분석 결과 양쪽성 계면활성제의 영향으로 안정적인 분산성을 확인하였다. 연마율의 경우 TEOA 함량이 증가함에 따라 HDP막의 연마량 감소가 확인되었다. The chemical mechanical polishing (CMP) process is a procedure that employs chemical and physical actions to flatten the pattern steps that appear on the wafer during processing and remove unnecessary thin films. Dispersants with an amphoteric surfactant structure do not significantly alter the polishing rate of the center and edges during the CMP process, but pH decreases over time and particle agglomeration occurs. In this study, stability studies were conducted by gradually adding triethanolamine to a slurry using a zwitterionic dispersant. Dispersion stability was confirmed using pH, conductivity, optical microscopy (OM), dynamic light scattering (DLS), viscosity, and zeta potential measurements. Additionally, the polishing rate of the slurry containing triethanolamine was compared and analyzed. As a result of this study, it was confirmed that pH was lowered by about 1 at room temperature and approximately 3 at 60°C, Additionally, it was observed that the higher the amount of Triethanolamine (TEOA) added, the smaller the change, indicating greater stability. The conductivity analysis showed an overall increase, with a higher increase as the TEOA content increased. Optical microscopy (OM) analysis revealed no significant change at room temperature, but particle agglomeration was confirmed in the case of the CMP slurry stored at 60°C. However, the slurry with added TEOA was confirmed to be stable regardless of temperature. Zeta potential analysis indicated that, compared to the CMP slurry, the slurry containing TEOA exhibited stable dispersibility without significant change from the initial state. Dynamic light scattering (DLS) analysis confirmed that the particle size of the CMP slurry increased to about 160 nm at room temperature and approximately 330 nm at 60°C, while the TEOA-added slurry remained stable with no significant change from the initial state. Viscosity analysis showed stable dispersibility due to the influence of the amphoteric surfactant. In terms of the polishing rate, it was confirmed that the polishing amount of the high-density plasma (HDP) film decreased as the TEOA content increased.

압전체를 이용한 약품 분사용 초음파 분사 노즐 시스템

고재석,김용현,김형수,조순행,최승철 한국마이크로전자및패키징학회 2003 마이크로전자 및 패키징학회지 Vol.10 No.4

압전 세라믹스를 이용하여 약품 분사용 초음파분사 노즐을 제작하였다. 정수장의 혼화 공정에 사용되는 약품(응집제)의 고효율 분산을 위해 분사 노즐을 설계하였으며 압전세라믹을 최적화하였다. 제작된 초음파 약품 분사 노즐을 패키징하여 정수장의 약품 혼화 과정에 적용하여 약품사용의 고 효율화와 사용량 저감을 위한 연구를 진행하였다. 압전체는 실리콘으로 마감처리를 하였으며 Al으로 패키징하였다. 본 초음파 분사 노즐 시스템을 적용하여 혼화지에 실험한 결과 약품의 순간 혼화를 촉진시키는 기술로 투입 약품량을 저감시킬 수 있을 것으로 판단된다. 초음파 발진 약품 분사시, 무발진과 비교하여 대장균 제거 효율에서 현저하게 높아졌다. A new type of ultrasonic spray nozzle was fabricated employing a piezoelectric device. The spray nozzle was designed to disperse chemicals in a water treatment mixing tank. The piezoelectric properties in ultrasonic spray nozzles were optimized to improve the dispersion of chemicals. The piezoelectrics were packaged in an aluminum case with silicone resin for the aqueous solution proof packaging. Chemicals were dispersed with high efficiency and the chemicals consumption was reduced by the ultrasonic fine particle spraying. The concentration of Escherichia coli in mixing tank was decreased remarkably using ultrasonic spray nozzle dispersion compared to the conventional methods.

Dispersion mechanisms of Arabic gum in the preparation of ultrafine silver powder

Yingfen Li,Weiping Gan,Xiaogang Liu,Tao Lin,Bei Huang 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.8

Finely divided silver micro-spheres were prepared with Arabic gum (AG) as dispersant through the chemicalreaction of AgNO3 and ascorbic acid. AG dispersive mechanisms in the preparation of silver powder are proposed inthe paper. The -COOH and -NH2 groups of AG reacted with Ag+ to form Ag+-AG complexes, followed by the nucleationof silver on AG polymer chains, which yielded silver spheres with an AG protection layer by reducing Ag+-AG complexeswith ascorbic acid. With the steric effect of AG, the prepared silver particles exhibit improved dispersibility. UV-Vis and FTIR spectra confirmed that silver particles were stabilized by AG.

RAMS의 실시간 기상장 예측 향상을 위한 최신 토지피복도 자료의 적용가능성 평가

원경미(Gyeong Mee Won),이화운(Hwa Woon Lee),유정아(Jeong Ah Yu),홍현수(Hyun Su Hong),황만식(Man Sik Hwang),천광수(Kwang Su Chun),최광수(Kwang Su Choi),이문순(Moon-Soon Lee) 한국대기환경학회 2008 한국대기환경학회지 Vol.24 No.1

Chemical Accident Response Information System (CARIS) which has been designed for the efficient emergency response of chemical accidents produces the real-time atmospheric fields through the Regional Atmospheric Modeling System, RAMS. The previous studies were emphasized that improving an initial input data had more effective results in developing prediction ability of atmospheric model. In a continuous effort to improve an initial input data, we replaced the land-use dataset using in the RAMS, which is a high resolution USGS digital data constructed in April, 1993, with the latest land-use data of the Korea Ministry of Environment over the South Korea and simulated atmospheric fields for developing a real-time prediction in dispersion of chemicals. The results showed that the new land-use data was written in a standard RAMS format and shown the modified surface characteristics and the landscape heterogeneity resulting from land-use change. In the results of sensitivity experiment we got the improved atmospheric fields and assured that it will give more reliable real-time atmospheric fields to all users of CARIS for the dispersion forecast in associated with hazardous chemical releases as well as general air pollutants.

Electrocoagulation of Disperse Dyebath Wastewater: Optimization of Process Variables and Sludge Production

Aygun, Ahmet,Nas, Bilgehan,Sevimli, Mehmet Faik The Korean Electrochemical Society 2021 Journal of electrochemical science and technology Vol.12 No.1

This study was conducted to investigate the effect of initial pH, current density, and electrolysis time on process performance in terms of decolorization and chemical oxygen demand (COD) removal from disperse dyebath wastewater (DDW) by mono-polar parallel laboratory scale electrocoagulation (EC) process. COD reduction of 51.3% and decolorization of 92.8% were obtained with operating cost of 0.19 €/㎥ treated wastewater for Al-Al electrode pair, while 90.5% of decolorization and 49.2% of COD reduction were obtained with operating cost of 0.20 €/㎥ treated wastewater for an Fe-Fe electrode pair. The amount of sludge production were highly related to type of the electrode materials. At the optimum conditions, the amount of sludge produced were 0.18 kg/㎥ and 0.28 kg/㎥ for Al-Al and Fe-Fe electrode pairs, respectively. High decolorization can be explained by the hydrophobic nature of the disperse dye, while limited COD removal was observed due to the high dissolved organic matter of the DDW based on auxiliary chemicals. Energy, electrode, and chemical consumptions and sludge handling were considered as major cost items to find a cost-effective and sustainable solution for EC. The contribution of each cost items on operating cost were determined as 10.0%, 51.1%, 30.5% and 8.4% for Al-Al, and they were also determined as 9.0%, 38.0%, 40.5% and 12.5% for Fe-Fe, respectively. COD reduction and decolorization were fitted to first-order kinetic rule.

Chemical management policies and a distribution model for chemical accidents

Min-Kyeong Yeo,Taek-Hyeon Han,Soon Seok Kim,Jin Ah Lee,Hyung-Geun Park 대한독성 유전단백체 학회 2017 Molecular & cellular toxicology Vol.13 No.4

This study compares and evaluates domestic and overseas chemical substance management systems, and compares domestic risk management systems and overseas cases regarding issues and vulnerabilities to propose a plan for improving these issues. The Chemical Substance Control Act is a more powerful law than the chemical substance control acts of other countries, but it requires a seamless system and information sharing between managing government agents to correct overlaps in the reporting system for chemical substance management. A comparison of chemical substance dispersion models finds that ALOHA, from the United States, fails to include environmental factors such as topographical changes and atmospheric conditions and does not consider the reactions of chemical substances in the atmosphere or the variables involved in granular chemical substances and mixtures. The Korean model (KORA) has the advantage of automatically completing risk assessments and scenarios for each accident type. However, it has the inconvenience of requiring users to directly input the target of protection in the event of a chemical accident. Overall, a chemical substance risk management system must include information about the toxicity of chemical substances and environmental factors.

Hyperbolic Averaged Models for Describing Dispersion Effects in Chromatographs and Reactors

Balakotaiah, Vemuri 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.2

We show that dispersion effects due to local velocity gradients and transverse molecular diffusion in chromatographs and chemical reactors can be better described in terms of averaged models that are hyperbolic in the longitudinal coordinate and time, and with an effective local time or length scale in place of the traditional axial dispersion coefficient. This description not only eliminates the use of artificial exit boundary conditions but also inconsistencies such as upstream propagation and infinite speed of signals associated with the traditional parabolic averaged models. We also show that the hyperbolic models can describe dispersion effects accurately and have a much larger region of validity in the physical parameter space compared to the traditional parabolic models. Our method of obtaining averaged models from the governing partial differential equations is based on the Lyapunov-Schmidt technique of classical bifurcation theory and is rigorous. We illustrate our approach using three well known chemical engineering problems.

Hyperbolic Averaged Models for Describing Dispersion Effects in Chromatographs and Reactors

Vemuri Balakotaiah 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.2

We show that dispersion effects due to local velocity gradients and transverse molecular diffusion in chromatographs and chemical reactors can be better described in terms of averaged models that are hyperbolic in the longitudinal coordinate and time, and with an effective local time or length scale in place of the traditional axial dispersion coefficient. This description not only eliminates the use of artificial exit boundary conditions but also inconsistencies such as upstream propagation and infinite speed of signals associated with the traditional parabolic averaged models. We also show that the hyperbolic models can describe dispersion effects accurately and have a much larger region of validity in the physical parameter space compared to the traditional parabolic models. Our method of obtaining averaged models from the governing partial differential equations is based on the Lyapunov-Schmidt technique of classical bifurcation theory and is rigorous. We illustrate our approach using three well known chemical engineering problems.