• 한국재료학회지
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• 제26권9호
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• pp.460-467
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• 2016

Activated carbons (ACs) have been used as EDLC (electric double-layer capacitor) electrode materials due to their high specific area, stability, and ecological advantages. In order to prepare ACs with high density and crystallinity, coal tar pitch (CTP) was activated by $K_2CO_3$ and the textural and electrochemical properties of the obtained ACs were investigated. Although the CTP ACs formed by $K_2CO_3$ activation had much smaller specific surface area and pore volume than did the CTP ACs formed by KOH activation, their volumetric specific capacitance (F/cc) levels as electrode materials for EDLC were comparable due to their higher density and micro-crystallinity. Structural characterization and EDLC-electrode performance were studied with different activation conditions of $CTP/K_2CO_3$ ratio, activation temperature, and activation period.

• 공업화학
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• 제25권3호
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• pp.330-336
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• 2014

추출-증류-결정의 조합에 의해 모델 콜타르 흡수유 중에 함유된 인돌의 정제를 검토했다. 흡수유는 4종류의 질소고리 화합물(9.2% 퀴놀린, 2.4% 이소퀴놀린, 4.7% 인돌, 2.4% 퀴날딘), 3종류의 2환 방향족 화합물(14.2% 1-메틸나프탈렌, 31.8% 2-메틸나프탈렌, 23.5% 디메틸나프탈렌), 5.5% 비페닐과 3.3% 페닐에테르의 9종류의 화합물로 구성되어 있다. 포름아미드 추출-증류-노말헥산을 사용한 용액 결정화의 조합의 채택에 의해 99.5% 인돌을 회수할 수 있었다. 본 연구를 통해 얻어진 실험적 결과를 이용하여 콜타르 흡수유 중에 함유된 인돌의 회수공정을 검토했다.

• Corrosion Science and Technology
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• 제16권3호
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• pp.115-127
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• 2017

Coal tar-coated pipes buried in a domestic nuclear power plant have operated under the cathodic protection. This work conducted the simulation of the coating performance of these pipes using a FEM method. The pipes, being ductile cast iron have been suffered under considerably high cathodic protection condition beyond the appropriate condition. However, cathodic potential measured at the site revealed non-protected status. Converting from 3D CAD data of the power plant to appropriate type for a FEM simulation was conducted and cathodic potential under the applied voltage and current was calculated using primary and secondary current distribution and physical conditions. FEM simulation for coal tar-coated pipe without defects revealed over-protection condition if the pipes were well-coated. However, the simulation for coal tar-coated pipes with many defects predict that the coated pipes may be severely degraded. Therefore, for high risk pipes, direct examination and repair or renewal of pipes are strongly recommended.

• Carbon letters
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• 제19권
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• pp.72-78
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• 2016

Spinnable pitches and carbon fibers were successfully prepared from petroleum or coal pyrolysis residues. After pyrolysis fuel oil (PFO), slurry oil, and coal tar were simply filtered to eliminate the solid impurities, the characteristics of the raw materials were evaluated by elemental analysis, ¹³C nuclear magnetic resonance spectrometer, matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF-MS), and so on. Spinnable pitches were prepared for melt-spinning carbon fiber through a simple distillation under strong nitrogen flow, and further vacuum distillation to obtain a high softening point. Carbon fibers were produced from the above pitches by single-hole melt spinning and additional heat treatment, for oxidization and carbonization. Even though spinnable pitches and carbon fibers were processed under the same conditions, the melt-spinning and properties of the carbon fiber were different depending on the raw materials. A fine carbon fiber could not be prepared from slurry oil, and the different diameter carbon fibers were produced from the PFO and coal tar pitch. These results seem to be closely correlated with the initial characteristics of the raw materials, under this simple processing condition.

• 공업화학
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• 제18권2호
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• pp.168-172
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• 2007

회분 병류 5단 평형추출에 의해 4종류의 질소고리화합물[indole(In), quinoline(Q), iso-quinoline(iQ), quinaldine(Qu)], 3종류의 2환 방향족화합물[1-methylnaphthalene(1MN), 2-methylnaphthalene(2MN), dimethyl naphthalene(DMN)], biphenyl과 phenyl ether로 구성된 모델 혼합물로부터 In의 분리를 검토했다. 본 연구의 원료로서 사용된 모델 혼합물은 콜타르 유분(유출온도범위: $240{\sim}265^{\circ}C$)을 구성하고 있는 성분 및 조성을 고려하여 작성했다. 추출용매로서는 Formamide 수용액을 사용했다. 4단 평형추출을 통해 In을 99% 이상 회수할 수 있었다. 5단 평형추출을 통해 얻어진 DMN을 기준성분으로한 In의 선택도는 63~118의 범위를 나타냈다. 본 연구를 통해 얻어진 실험적 결과와 이전의 연구결과를 이용하여 콜타르 중에 함유된 In의 분리 및 회수공정을 검토했다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권7호
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• pp.3409-3416
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• 2012

Aim: It is well known that polycyclic aromatic hydrocarbons (PAHs) such as benzo (a) pyrene have carcinogenic properties and may cause many types of cancers in human populations. Genetic susceptibility might be due to variation in genes encoding for carcinogen metabolizing enzymes, such as cytochrome P-450 (CYP450). Our study aimed to investigate the effect of genetic polymorphisms of CYP1A1 (m1 and m2) on genetic damage in 115 coal-tar workers exposed to PAHs at their work place. Methods: Genetic polymorphisms of CYP1A1 were determined by the PCR-RFLP method. Comet and buccal micronucleus assays were used to evaluate genetic damage among 115 coal tar workers and 105 control subjects. Results: Both CYP1A1 m1 and CYP1A1 m2 heterozygous and homozygous (wt/mt+mt/mt) variants individually as well as synergistically showed significant association (P<0.05) with genetic damage as measured by tail moment (TM) and buccal micronuclei (BMN) frequencies in control and exposed subjects. Conclusion: In our study we found significant association of CYP1A1 m1 and m2 heterozygous (wt/mt)+homozygous (mt/mt) variants with genetic damage suggesting that these polymorphisms may modulate the effects of PAH exposure in occupational settings.

• 한국환경성돌연변이발암원학회지
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• 제20권1호
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• pp.34-39
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• 2000

Although shipbuilding workers were exposed to a variety of genotoxic compounds including polycyclic aromatic hydrocarbons (PAHs), limited number of studies were conducted to evaluate the biomarkers related to PAH exposure in painting workers in shipbuilding industry. One hundred and thirty three workers including 73 employees using coal tar paints were recruited from a shipbuilding company located in South Korea. Urinary 1-hydroxypyrene glucuronide (1-OHPG), as internal dose of PAH exposure, were measured by synchronous fluorescence spectroscopy after immunoaffinity purification using monoclonal antibody 8E11. Glutathione S-transferase (GST)M1 and GSTT1 genotypes were assessed by multiplex PCR. Information on demographic characteristics, smoking gabit, diet, job title, use of personal protective equipments were collected by self-administered questionnaire. Urinary 1-OHPG were higher in workers using coal tar paints than in workers using general paints, however, the difference was not statistically significant (p=0.20, Mann-Whitney U test). Urinary 1-OHPG levels in smokers were higher than in non-smokers (p<0.05 by Mann-Whitney U test) and there was a significant increase in urinary 1-OHPG levels with the numbers of cigarettes consumed per day (Spearman's correlation coefficient = 0.28, p=0.02). Genetic polymorphisms of GSTM1 and GSTT1 did not influence the level of 1-OHPG in study subjects. Multiple regression analysis show that smoking is the only significant predictor for lon-transformed 1-OHPG (overall model R2=0.1). These results suggest that workers using coal tar paints were exposed to significant amount of PAHs and individual difference in xenobiotic metabolism might affect the levels of internal dose of PAHs.

• Korean Chemical Engineering Research
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• 제50권6호
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• pp.1034-1042
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• 2012

본 연구에서는 다양한 석탄 연구에 적용되고 있는 층류 반응기(LFR)를 이용하여 열분해와 연소 분위기에서 탄종에 따른 화염형상을 분석하였고, 휘발분 함량이 다른 두 석탄의 타르와 수트의 발생률을 구하였으며 이를 촤 입자의 표면적 및 표면 형상 변화와 함께 비교하였다. 본 연구에서 사용된 층류 반응기는 화염형상을 가시적으로 분석하기에 뛰어나므로 석탄이 반응할 때 생성되는 수트 클라우드를 측정하여 그 형상 변화를 근거로 탈휘발의 종료 지점을 가정하였다. 휘발분 함량이 많은 Berau 탄은 Glencore A.P. 탄보다 수트 클라우드의 폭과 길이가 증가하였고, 연소 분위기에서는 촤와 수트의 산화반응에 의하여 열분해 때보다 화염과 수트 클라우드의 길이가 짧아지면서 더 밝은 빛을 내었다. 포집높이 50 mm까지에서는 휘발분 함량이 많은 Berau 탄의 타르와 수트 발생률이 Glencore A.P. 탄보다 작았다. 이는 석탄 연료의 조성 중 Berau 탄내에 상대적으로 높은 산소 성분의 함량과 OH- 같은 라디칼들로 인해 타르가 산화되기 때문이다. 반면에, 50 mm 이후부터는 Berau 탄이 Glencore A.P. 탄보다 더 많은 타르와 수트의 발생률이 나타나며 탄종간에 수트 발생률의 역전현상이 일어나는데 이는 촤 입자 내부의 휘발물질과 탈휘발 과정에서 생성된 화염 속의 잔여 타르 및 light gas 성분이 반응하여 수트를 발생시켰기 때문이다. 이를 통해서 석탄 내의 휘발분의 함량과 산소농도는 수트 클라우드의 길이와 폭에 명확한 영향을 주며, 수트 발생률에 매우 중요한 인자라는 것을 확인할 수 있었다. SEM과 B.E.T.의 결과로부터 탈휘발이 종료된 후에도 촤 입자 내부의 잔존 휘발물들이 분출되면서 타르와 수트가 발생함을 확인할 수 있었고, 각 탄의 휘발분 함량과 기공의 발달 차이를 통해서 100 mm 이후에 나타난 타르와 수트의 발생률 역전 현상을 설명할 수 있었다.

• 한국수소및신에너지학회논문집
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• 제28권4호
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• pp.323-330
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• 2017

Ash remaining after coal combustion was used as a catalyst support for tar steam reforming with various proportions of $Al_2O_3$ added for higher reforming efficiency. At a constant Ni content of 12 wt%, a coal ash and $Al_2O_3$ were mixed at a ratio of 5:5, 7:3, 9:1. As a result, the catalytic activity for toluene steam reforming was improved by adding $Al_2O_3$ at $500-600^{\circ}C$. The catalysts with ratio 7:3 and 5:5 reached toluene conversion of 100% above $700^{\circ}C$. When comparing the catalysts in which the coal ash and $Al_2O_3$ mixed at a ratio of 5:5 and 7:3 with the Ni/Al catalyst, it was concluded that this coal ash catalyst has efficient catalytic performance.

• Korean Chemical Engineering Research
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• 제59권2호
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• pp.232-238
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• 2021

The development of a low cost catalyst with high performance and small amount of carbon deposition on catalyst from toluene steam reforming were investigated by using coal ash as a support material. Ni-loaded coal ash catalyst showed similar catalytic activity for toluene steam reforming compared with the Ni/Al2O3. At 800 ℃, the toluene conversion was 77% for Ni/TAL, 68% for Ni/KPU and 78% for Ni/Al2O3. Ni/TAL showed similar toluene conversion to Ni/Al2O3. However, Ni/KPU produced higher hydrogen yield at relatively lower toluene conversion. Ni/KPU catalyst showed a remarkable ability of suppressing the carbon deposition. The difference in coke deposition and hydrogen yield is due to the composition of KPU ash (Ca and Fe) which increase coke resistance and water gas shift reaction. This study suggests that coal ash catalysts have great potential for the application in the steam reforming of biomass tar.