• 한국대기환경학회지
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• 제26권6호
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• pp.633-648
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• 2010

The study was performed to elucidate the characteristics of VOCs at distinct monitoring sites in urban atmosphere; one is at a roadside in downtown inland city of Jeonju, and the other is at an industrial site in Gunsan near coastal area. The ambient samples were collected for 24 hours in two-bed adsorbent tubes by using MTS-32 sequential tube sampler equipped with Flex air pump every 16 days in a roadside and a industrial complex from February to November in 2009. VOCs were determined by thermal desorption coupled with GC/MSD. Major individual VOCs in roadside samples were shown as following order in magnitude: toluene>m,p-xylene>ethyl benzene>decanal; and those in the industrial complex samples were as follows: toluene>ethanol>ethyl acetate>decanal>m,pxylene. High benzene concentration in the roadside was more frequently occurred than in the industrial complex. However ambient level of toluene in the industrial complex was higher than that in the road side. Results from roadside sample analysis showed that nonane and 1,2,4-trimethylbenzene were very frequently observed with higher concentrations than those in the industrial complex. It seems that nonane and 1,2,4-trimethylbenzene could be the source characteristics for the roadside air. From the diurnal variation, it was found that concentrations of benzene, ethylbenzene, xylene, nonane and 1,2,4-trimethylbenznene in the roadside were higher during rush hours; but those in the industrial complex were higher from 10 to 16 LST when the industrial activities were animated. On weekly base, the concentration of benzene, toluene, ethylbenzene and m,p-xylene in the roadside were higher specifically on Wednesday, but those in the industrial complex were higher on Sunday. It was found that the general trends of VOCs levels at both sites significantly influence on seasonal changes. The results of factor analysis showed that the VOCs in the roadside were mainly affected by the emission of vehicles and the evaporation of diesel fuel, meanwhile those in the industrial complex were influenced by the evaporation of solvents and vehicular emission.

• 대한환경공학회지
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• 제32권2호
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• pp.209-218
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• 2010

감전동 측정소에서 측정한 일반대기의 휘발성유기화합물 중 방향족화합물이 전체의 51.3%로 가장 높은 농도를 나타내었고 다음이 paraffin류(44.2%), olefin류(2.7%), alkyne류(1.8%)의 순이었으며 대연동 측정소는 paraffin류가 전체의 56.7%를 나타내어 가장 높았으며 다음이 aromatic류(35.9%), olefin류(6.1%), alkyne류(1.3%)순으로 조사되었다. POCP를 고려한 오존생성 기여도는 toluene이 30.6%로 가장 높았으며 그 다음으로 propane, m/p-xylene, ethylbenzene, 1,2,4-trimethylbenzene이 각각 10.2%, 9.4%, 7.4%, 5.2%로 높았다 상위 5가지 물질의 기여도가 전체의 62.8%로 다른 물질들의 기여도 보다 비교적 높은 것으로 나타났다. 한편 상위 32종의 VOCs가 전체 VOCs중 97.6%로 조사되어 나머지 14개 VOCs물질의 오존생성 기여율은 미미한 것으로 조사되었다. 고농도 오존이 발생한 시점과 $NO_2$/NO의 비의 시간 변화율이 바뀌는 시점은 대체적으로 아주 유사한 현상을 보였다. 이것은 고농도 오존과 광화학적 현상이 밀접한 관계를 보인다는 것을 간접적으로 시사한다. NO의 $NO_2$로의 전환이 오존의 고농도 현상에 중요한 역할을 하고 있다는 것을 알 수 있다.

• 한국환경보건학회지
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• 제23권4호
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• pp.82-90
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• 1997

본 실험은 석유의 주요성분인 benzene, toluene, p,m,o-xylene, ethylbenzene, n-propylbenzene, 1,2,4-trimethylbenzene, n-butylbenzene 등 light hydrocarbon에 오염된 토양의 회복에 필요한 최적 용매추출 조건을 밝히기 위하여 실시하였다. 토양의 수분함량이 증가할수록 추출효율은 감소하였으며, Methanol을 용매로 사용하였을때에 BTEX화합물은 1시간 추출시 최고 추출효율에 도달하였으며 고분자 hydrocarbon은 4시간이상 추출시 최고 추출효율에 도달하였다. 2-Propanol을 추출용매로 사용할때는 모든 light hydrocarbon은 추출 4시간 경과시 최고의 추출효율을 나타냈다. 추출용매와 토양의 비율이 2:1일때 가장 경제적이고 효율적이고 추출이 이루어 졌으며, 0.4mg/g이상의 토양오염 농도에서 최적의 추출효과가 나타났다. 위의 최적조건으로 light hydrocarbon 오염토양을 batch extraction을 이용하여 추출하였을 때 평균 66%의 light hydrocarbon이 회수되었으며, 회수율은 토양의 종류, 추출용매의 종류 그리고 hydrocarbon의 종류에 따라 좌우되었다. 본 연구의 결과는 석유에 오염된 토양의 회복을 위한 토양세척에 사용될 수 있을 것으로 사료된다.

• 한국환경과학회지
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• 제18권5호
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• pp.517-525
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• 2009

We measured ambient concentrations of hazardous air pollutants such as volatile organic compounds (VOCs) and aldehydes in residential areas nearby small and medium scale shipbuilding companies. The VOC concentrations were higher during the normal operation periods than vacation at which almost all operations were shutdown. Concentrations of VOCs was higher, as the sampling site was nearer from shipbuilding companies. The major components of VOCs were m,p-xylene, ethylbenzene, o-xylene, toluene, and 1,3,5-trimethylbenzene which had been found as major VOC compounds emitted from painting processes of shipbuilding in the previous studies. The major components of aldehydes analyzed were benzaldehyde, acrolein, formaldehyde, and acetaldehyde. The concentration of aldehydes was highest at the furthest sampling point from shipbuilding companies because the formation of aldehyde compounds could be occurred by the secondary chemical reactions of VOCs. The results of this study shows a proper counterplan need to be established for the reduction of hazardous air pollutants emitted from small and medium scale shipping companies.

• 설비공학논문집
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• 제15권1호
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• pp.40-49
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• 2003

This study has been conducted to identify and quantify the emissions of Volatile Organic Compounds (VOCs) from a new carpet. The carpet sample consists of polypropylene cushion and latex backing. The VOCs have been sampled on sorbent tubes and analyzed by thermal desorption unit and GC/MSD. For over 240 hours, concentration of VOCs has been measured in a small chamber made of stainless steel. With the measured data, emission factor and mass balance have been considered. The experiments have been conducted in accordance with ASTM D5116-97. The carpet has emitted a variety of VOCs, but in this study, 7 VOCs compounds have been considered： chlorobenzene, ethylbenzene, styrene, isopropylbenzene, bromobenzene, 2-chlorotoluene, and 1,2,3-trimethylbenzene. The results show that the concentrations of VOCs and the emission factors have exponentially decayed from relatively high level to low level with time. The gradients of the concentration of VOCs and emission factors are different for various components. It is found that styrene, 2-chlorotoluene are emitted more than others with higher concentrations.

• 한국연소학회지
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• 제22권3호
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• pp.35-40
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• 2017

Jet aviation fuel is one of liquid fuel which are used in aircraft engines. Korean domestic jet fuel, called Jet A-1, is tested for measurement of ignition delay time by using a shock tube manufactured recently. The temperature varies from 680 to 1250 K and the pressure and equivalence ratio of Jet A-1/air are fixed 20 atm and 1.0, respectively, for this experiment. The ignition delay time data of Jet A-1 are compared with those of Jet A, which has similar properties to Jet A-1. The behavior of negative-temperature-coefficient (NTC) is observed in the temperature range 750-900 K. In addition, ignition delay time of iso-octane is measured, which is one of the surrogate components for jet aviation fuel. The experimental data are compared and validated with the previous results from the literatures. A surrogate fuel for the present Jet A-1 consists of 45.2% n-dodecane, 32.1% iso-octane, and 22.7% 1,3,5-trimethylbenzene. The predicted ignition delay time for the surrogate agrees well with the measured one for Jet A-1.

• 대한화학회지
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• 제25권1호
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• pp.26-29
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• 1981

양이온 교환 및 알루미늄 추출시킨 모더나이트와 제올라이트 Y 촉매에서 m-크실렌의 반응이 마이크로펄스방법으로 연구되었다. H-모더나이트 촉매에서 전처리온도가 높아지거나 Si/Al비가 증가할 때 동종간 주고 받기반응생성물이 크게 증가했다. $Ba^{2+}-, Mg^{2+}- $이온교환한 모더나이트촉매에서 양이온교환정도가 증가할에따라 트리메틸벤젠의 생성량이 급격히 감소했다. m-크실렌의 동종간 주고 받기반응에서는 모더나이트의 산성도의 영향과 아울러 촉매 유효세공의 크기에 따른 형상 선택성을 보여준다.

• 실내환경 및 냄새 학회지
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• 제17권4호
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• pp.389-395
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• 2018

The odor substances generated in a feed manufactory operating for the commercialization of animal-vegetable materials were analyzed and the odor reduction efficiency by a chemical scrubber was evaluated. The major causative substances in the feed manufactory comprised about 45.4% of ketone compounds and about 13.3% of aldehyde compounds. On the other hand, the removal efficiencies of diacetyl and acetoin as ketone compounds were 77.3% and 78.1%, respectively, by a chemical scrubber. Additionally, the removal efficiencies of acetaldehyde, butyraldehyde, valeraldehyde, 2-furancarboxaldehyde, and nonanal were 86.0%, 78.9%, 67.4%, 52.8%, and 71.9%, respectively. These rates were higher than the odor generation substance contribution rate as a result of treating the exhaust gas generated from the feed manufactory by the chemical scrubber using 5% of C3. It was also found that xylene, methylcyclopentane, benzene, ethylbenzene, 1,3,5-trimethylbenzene, and decane were almost not removed.

• 공업화학
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• 제7권1호
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• pp.129-135
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• 1996

여러 가지 탄화수소를 분리할 수 있는 활성화된 결정성 thiourea의 포접성능이 조사되었다. $C_6$부터 $C_9$의 탄화수소의 단일성분, 이성분계에 대한 포접 평형 자료가 제시되었다. 만일성분에 대한 활성 thiourea의 포접능력은 탄화수소의 분자크기에 불규칙적인 거동을 하였으며 온도에 무관함 알 수 있었다. 이성분계 분리에서 분자량이 낮은 탄화수소가 분자량이 높은 탄화수소보다 활성 thiourea에 선택성이 컸다. $C_9$방향족 이성체의 분리를 통하여 활성 thiourea는 메틸그룹의 위치 즉 분자의 형상(configuration)에 따라 영향을 미침을 알 수 있었다. $C_9$방향족 잔사유로부터 pseudocumene은 활성 thiourea에 의하여 99.5wt%순도로 분리가 가능하였다. 본 연구에서 조사된 이성분계에 대한 활성 thiourea의 분리능력은 증류, 추출결정화, 부가결정화보다 큼을 알 수 있었다.

• 한국환경보건학회지
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• 제24권2호
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• pp.74-79
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• 1998

본 실험은 light hydrocarbon에 오염된 토양을 용매 추출할 때 계면활성제의 영향을 평가하고자 6가지의 계면활성제 (Witbreak DPG-482, Witbreak DRA-22, Witcomul 4016, Witcolate SL-1, Adsee 799, Triton X-100)와 2가지 용매(물, 메타놀)를 대상으로 실험하였다. Light hydrocarbon으로는 benzene, toluene, ethyl bnzene, o-xylene, m-xylene, p-xylene, n-propyl benzene, 1,2,4-trimethyl benzene, 그리고 n-butyl benzene등 9가지를 대상으로 하였다. 계면활성제중 Adsee-799과 Witbreadk DRA-22가 토양중 light hydrocarbon의 물추출 효율을 다소 증가시키는 것으로 나타나고 있으며, 나머지 계면활성제는 효과가 없었다. 또한 물중의 계면활성제의 농도가 0.5%이하에서는 효과가 없는 것으로 나타나고 있으며, 계면활성제의 농도가 4%일때 평균 10.8%의 추출증가 효과가 있었다. 메타놀을 추출용매로 사용할 때에는 Witbread DPG-782와 Witbreak DRA-22가 약 10%의 추출증가 효과를 나타내고 있었다.