• 한국지하수토양환경학회지:지하수토양환경
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• 제15권5호
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• pp.40-45
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• 2010

In this study, methane production by reuse of screened soil of landfill was estimated and the effect of application of landfarming for the reduction of methane was investigated. The study soil sampled from S closed landfill contains VS 9.8~12.8% and its BOD/COD is 0.31~0.33 which is more than three times over 0.1, the BOD/COD stabilization criteria of Ministry of Environment. The effective remediation technology for the reduction of organics of soil, landfarming was applied to the screened soil for 60 days. VS and TPH removal showed 5.2~8.3% and 67~74% respectively, and the reduction of VS until 30 day charged 70% of the total reduction. BMP test showed 27.77~30.46 mL $CH_4$/g VS and total methane production from total screened soil for remediation is expected about 260.4 $CH_4$ ton. Expected amount of methane production of the screened soil by landfarming application is 12.9 $CH_4$ ton, which shows 95% gas reduction effect and landfarming is effective for the reduction of methane production from screened soil of landfill.

• Journal of Microbiology and Biotechnology
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• 제22권10호
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• pp.1452-1456
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• 2012

The anaerobic oxidation of methane (AOM) in anaerobic sewage sludge was characterized. The net methane oxidation was observed in samples amended with methane plus sulfate or with methane alone, whereas methane formation was observed in the samples without methane, indicating that methane oxidation and formation occurred simultaneously. The ratio of the net methane oxidation rate to $H_2S$ formation was 100:1, suggesting that the AOM was not closely associated with sulfate reduction in the anaerobic sludge. The net AOM was positively associated with the methane concentration and sludge dilution ratio. However, the rate of AOM was negatively correlated with organic substrate (acetate) concentration. Therefore, the production and oxidation of methane could be controlled by environmental conditions and dissolved organic compounds in the bulk solution.

• 한국자동차공학회논문집
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• 제12권5호
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• pp.66-72
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• 2004

In this study, the effects of oxygen component in fuel and exhaust gas recirculation(EGR) method on the exhaust emissions has been investigated for a D.I. diesel engine. It was tested to estimate change of exhaust emission characteristics for the commercial diesel fuel and oxygenate blended fuel which has five kinds of blending ratio. Dimethoxy methane(DMM) contains oxygen component 42.5% in itself, and it is a kind of effective oxygenated fuel for reduction of smoke emission. It was affirmed that smoke emission was decreased with increasing of DMM blending ratio. But, NOx emission was increased compared with commercial diesel fuel. It was needed a NOx reduction counterplan that EGR method was used as a countermeasure for NOx reduction. It was found that simultaneous reduction of smoke and NOx emission was achieved with DMM blended fuel and cooled EGR method(1015%).

• 한국자동차공학회논문집
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• 제10권1호
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• pp.32-44
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• 2002

Selective catalytic reduction of nitric oxide by methane in the presence of excess oxygen was investigated over copper and cobalt ion-exchanged ZSM-5 zeolites. Copper ion-exchanged ZSM-5(Cu-ZSM-5) has the limitations for commercial applications to lean-bum gasoline and diesel engines due to low thermal stability and resistance to water vapor and sulfur dioxide. But cobalt ion-exchanged ESM-5(Co-ZSM-5) is more active at high temperatures and also stable to water vapor and sulfur dioxide for catalytic reduction of nitric oxide by methane. The catalytic activity of Cu-ZSM-5 for NO reduction increases with increasing temperatures, reaches the maximum conversion of 23.0% at 350\"C. and then decreases with higher temperatures. In the meantime catalytic activities of Co-ZSM-5 show the maximum conversion of 25.8% at $500^{\circ}C$ Therefore Co-ZSM-5 catalysts have higher thermal stability at high temperatures. Catalytic activities of both zeolites were remarkably enhanced with the existence of oxygen in the exhaust. It is noted that the catalytic activity of Cu-ZSM-5 decreases with the increasing concentration of methane while the catalytic activity of Co-ZSM-5 decreases with increasing contents of methane in the exhaust. This may imply the existence of different paths of NO reduction by methane in the presence of excess oxygen fur Cu-ZSM-5 and Co-ZSM-5 catalysts. For binary metal ionexchanged ZSM-5, the primary ion-exchanged metal may be masked by secondary ion-exchanged component, which plays the important role for catalytic activities of binary metal ion-exchanged ZSM-5, Therefore CuCo-ZSM-5 catalysts show the similar volcano-shaped curves to Cu-ZSM-5 catalysts between the activity and temperature. It Is interesting that the activities of CoCu-ZSM-5 catalysts indicate almost no dependence on the concentration of methane in the exhaust.aust.

• Animal cells and systems
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• 제8권4호
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• pp.281-288
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• 2004

The change in relationships between methane production and sulfate reduction was investigated in reclaimed rice field soils at different time points after reclamation of tidal flat in Korea. Sulfate concentrations of soils in the ca. 60-year-old and 26-year-old reclaimed rice fields were much lower than that in a natural tidal flat. During 60 d of anaerobic incubation, total methane production and sulfate consumption of the soil slurries were 7.0 ${\mu}$mol $CH_4$/g and 8.2 ${\mu}$mol $SO_4^{2-}$/g in the 60-year-old rice field, 5.6 ${\mu}$mol $CH_4$/g and 12.7 mmol $SO_4^{2-}$/g in the 26-year-old rice field, and ca. 0 mmol $CH_4$/g and 22.4 ${\mu}$mol $SO_4^{2-}$/g in a natural tidal flat. Relative percent electron flow through sulfate reduction in the 60-year-old rice field was much lower (50.8%) compared with the 26-year-old rice field (69.3%) and the tidal flat (99.9%). The addition of an inhibitor of methanogenesis (2-bromoethanesulfonate) had no effect on sulfate reduction in the soil slurries of the reclaimed rice fields. However, instant stimulation of methane production was achieved with addition of an inhibitor of sulfate reduction (molybdate) in the soil slurries from the 26-year-old reclaimed rice field. The specific inhibitor experiments suggest that the relationship of methanogenesis and sulfate reduction might become mutually exclusive or syntrophic depending on sulfate content in the soil after reclamation. Sulfate, thus sulfate reduction activity of sulfate-reducing bacteria, would be an important environmental factor that inhibits methane production and determines the major pathway of electron and carbon flow in anaerobic carbon mineralization of reclaimed rice field soils.

• 한국재료학회지
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• 제28권12호
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• pp.725-731
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• 2018

We investigate the reduction of $SnO_2$ and the generation of syngas($H_2$, CO) using methane($CH_4$) and hydrogen($H_2$) or a mixed gas of methane and hydrogen as a reducing gas. When methane is used as a reducing gas, carbon is formed by the decomposition of methane on the reduced Sn surface, and the amount of generated carbon increases as the amount and time of the supply of methane increases. However, when hydrogen is used as a reducing gas, carbon is not generated. High purity Sn of 99.8 % and a high recovery rate of Sn of 93 % are obtained under all conditions. The effects of reducing gas species and the gas mixing ratio on the purity and recovery of Sn are not significantly different, but hydrogen is somewhat more effective in increasing the purity and recovery rate of Sn than methane. When 1 mole of methane and 1 mole of hydrogen are mixed, a product gas with an $H_2/CO$ value of 2, which is known to be most useful as syngas, is obtained.

• Korean Chemical Engineering Research
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• 제48권1호
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• pp.103-109
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• 2010

하폐수 처리과정에서 발생되는 슬러지는 주로 혐기소화에 의해 처리되며 슬러지를 감량하고 메탄을 생산할 수 있어 많이 이용되고 있다. 슬러지의 전처리는 혐기소화의 율속단계인 가수분해를 높여 처리속도를 향상시키므로 많은 연구가 진행 중이다. 본 연구에서는 열, 초음파, 열-알칼리의 전처리 기술에 따른 슬러지의 가수분해(가용화) 효과와 전처리한 슬러지를 혐기소화하여 메탄 생산량과 슬러지의 감량 효과를 비교하였다. 하수와 폐수 슬러지 가용화율은 열-알칼리 동시 처리한 경우에는 67과 70%로 가장 높았고 다음으로 초음파 처리와 열처리가 40% 이상의 비슷한 가용화율을 보였다. 혐기소화 가스의 메탄 함량은 45~70% 범위로 유지되었고 전처리한 슬러지가 control에 비해 높게 나타났다. 메탄 생산량은 열처리, 초음파 처리, 열-알칼리를 같이 처리한 경우가 control에 비해 각각 하수슬러지는 2.6, 2.7, 3.5배, 폐수 슬러지는 3.5, 4.1, 4.2배 증가하였다. 혐기소화 슬러지의 감량효과는 전처리한 슬러지가 control에 비해 5~19% 포인트 높게 나타났으며 열-알칼리 처리한 경우가 초음파와 열처리에 비해 우수한 감량 효과를 보였다. 위의 결과로부터 전처리가 메탄 생산량에서 뿐만 아니라 슬러지 처리처분 비용 절감에 있어서도 중요한 역할을 함을 확인할 수 있었고 열-알칼리 동시 처리가 가장 우수한 성능을 보였다.

• 에너지공학
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• 제12권2호
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• pp.124-130
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• 2003

본 연구에서는 정적연소실을 이용하여 차량용 대체연료로써 메탄 및 수소첨가 메탄의 연소특성을 수소첨가율, 점화위치 및 점화방법에 따라 고찰하였다. 그 결과 연소효율, 최고연소압력 등과 같은 연소특성을 악화시키지 않고 희박 혼합기 조건하에서도 MSCDI 장치 사용에 의해 전 연소시간과 NO 농도를 저감시킬 수 있었다. 또한, 수소를 천연가스의 주 성분인 메탄에 혼합함에 따라 전 연소시간은 순수 메탄만을 사용할 때에 비해 단축되었으며, 이와 동시에 연소촉진율도 순수 메탄만을 사용하였을 때에 비해 상당히 향상되었다.

• 한국물환경학회지
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• 제30권5호
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• pp.559-567
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• 2014

Since the ocean dumping of organic wastes is prohibited under the London Convention, the need for land treatment of food waste leachate (FWL) has significantly been growing in recent years. This study was conducted to use thermal solubilization to turn FWL into a form that can easily be degraded during the anaerobic digestion process, thereby reducing the percentage of solids and increasing the production of methane. To derive the optimal operating conditions of thermal solubilization, a laboratory-scale reactor was built and operated. The optimal reaction temperature and time turned out to be $190^{\circ}C$ and 90 min, respectively. The BMP test showed a methane production of 465 mL $CH_4/g$ $COD_{Cr}$ and a biodegradation rate of 90.1%. The production of methane rose by about 15%, compared with no the application of thermal solubilization. To reduce the solid content of FWL and improve the methane production, therefore, it may be helpful to apply thermal solubilization to pre-treatment facilities for anaerobic digestion.

• Bulletin of the Korean Chemical Society
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• 제31권1호
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• pp.120-124
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• 2010

Monometallic, bimetallic and trimetallic particles consisting of different weight compositions of Pt-Pd-Rh over pure alumina wash coats have been synthesized and their catalytic performance on methane conversion was studied from 150 to $600^{\circ}C$. Different catalyst formulations with variable Pt, Pd and Rh contents for bimetallic and trimetallic systems were tried and $Pt_{(1.5)}Rh_{(0.3)}/Al_2O_3$ and $Pt_{(1.0)}Pd_{(1.0)}Rh_{(0.3)}/Al_2O_3$ shows low $T_{50}$ and $T_{90}$ temperatures. Bimetallic and trimetallic particle synergism acts as three way catalysts and therefore, all the catalysts show 100% methane conversion. The effect of supports such as $ZrO_2$ and $TiO_2$ on methane combustion was investigated; from $T_{50}$ and $T_{90}$ results both $Al_2O_3$ and $ZrO_2$ are suitable supports for low temperature methane combustion.