• 한국환경농학회지
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• 제32권4호
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• pp.359-365
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• 2013

BACKGROUND: Methane ($CH_4$) emission is calculated using the default $CH_4$ emission factor as recommended by the International Panel on Climate Change(IPCC guidelines). However, the default emission factor has been derived using including the data from other countries having different soil and environmental conditions and may not reflect the real $CH_4$ emission rates in Korea. The objective of this study was to estimate the baseline emission factor of $CH_4$ in Korean paddy soils during rice cultivation. METHODS AND RESULTS: Methane emission patterns were characterized in four different paddy soils across country for a consecutive 3 years during the rice cultivation period. Rice plants were cultivated under continuous flooding and fertilized using the recommended chemical fertilization in Korea ($N-P_2O_5-K_2O$=90-45-57kg/ha). The mean $CH_4$ emission rate was 2.32 kg $CH_4$/ha/day and the uncertainty of the investigated data was 21.7%, with a valuable error range at 1.82-2.82 kg $CH_4$/ha/day with a 95% confidence interval. CONCLUSION(S): Conclusively, the Korean paddy soils' baseline emission factor of $CH_4$ is approximately 2.32 kg $CH_4$/ha/day and can be used to estimate the $CH_4$ emissions more exactly.

• Journal of Animal Science and Technology
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• 제45권6호
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• pp.997-1006
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• 2003

본 연구는 우리나라에서 가축 장내발효에 의한 메탄배출 통계 기반을 구축하기 위해 수행되었다. 메탄 배출량을 추정하기 위해 가축은 소, 돼지, 가금, 면양, 산양으로 대분류하였고, 소는 한우와 젖소로 분류하여 각각 한우 송아지, 한우 비육우, 한우 번식우, 젖소 송아지, 젖소 비육우, 착유우로 세분류하였다. Tier 2 방법에 의한 메탄 배출계수는 각 세분류 집단의 가축의 생산성, 생체중, 도체중, 일당 증체량, 소화율을 근거로 하여 산출되었다. 한우의 배출계수는 39～49kg/head/year 정도로 IPCC에서 제시한 Tier 1의 47kg/head/year과 유사한 수준이었고, 젖소의 배출계수는 107 kg/head/year로 Tier 1 배출계수, 118kg/head/ year 보다 다소 낮게 나타났다. Tier 2 방법으로 추정한 가축 장내발효에 의한 메탄 배출량은 2001년, 총 126.8톤이었고 각 세분류별 메탄 배출량은 한우, 젖소, 돼지, 면양, 산양, 말에서 각각 61.70, 47.76, 13.08, 2.25, 0.17, 0.01 톤으로 나타났다. 본 연구에서 온실가스 배출추정 방법으로, Tier 1을 Tier 2로 대체하므로써 우리나라 가축 장내발효에 의한 메탄배출 통계의 정확성과 신뢰성이 개선된 것으로 사료된다.

• 한국토양비료학회지
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• 제48권4호
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• pp.271-277
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• 2015

Anaerobic decomposition of organic material in flooded rice fields produces methane, which escapes to the atmosphere primarily by transport through the rice plants. The annual amount of $CH_4$ emitted from a given area of rice is a function of the number and duration of crops grown, water regimes before and during cultivation period, and organic and inorganic soil amendments. Soil type, temperature, and rice cultivar also affect $CH_4$ emissions. The field experiment was conducted for three years to develop methane emission factor for water regime before the cultivation period from the rice fields. It was treated with three different water regimes prior to rice cultivation, namely: non-flooded pre-season < 180 days, non-flooded pre-season > 180 days, flooded per-season in which the minimum flooding interval is set to 30 days. Methane emission increased with days after transplanting and soil redox potential (Eh) decreased rapidly after flooding during the rice cultivation. The average methane emission fluxes were $5.47kg\;CH_4\;ha^{-1}day^{-1}$in flooded pre-season > 30 days, 5.04 in non-flooded pre-season < 180 days and 4.62 in non-flooded pre-season > 180. Methane emission flux was highly correlated with soil temperature and soil Eh. Rice yields showed no difference among treatments with water regime before the cultivation period.

• 대한기계학회논문집B
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• 제31권4호
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• pp.384-391
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• 2007

Hydrogen-blending effects in flame structure and NO emission behavior are numerically studied with detailed chemistry in methane-air counterflow diffusion flames. The composition of fuel is systematically changed from pure methane to the blending fuel of methane-hydrogen through $H_2$ molar addition up to 30%. Flame structure, which can be described representatively as a fuel consumption layer and a $H_2$-CO consumption layer, is shown to be changed considerably in hydrogen-blending methane flames, compared to pure methane flames. The differences are displayed through maximum flame temperature, the overlap of fuel and oxygen, and the behaviors of the production rates of major species. Hydrogen-blending into hydrocarbon fuel can be a promising technology to reduce both the CO and $CO_2$ emissions supposing that NOx emission should be reduced through some technologies in industrial burners. These drastic changes of flame structure affect NO emission behavior considerably. The changes of thermal NO and prompt NO are also provided according to hydrogen-blending. Importantly contributing reaction steps to prompt NO are addressed in pure methane and hydrogen-blending methane flames.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2017년도 추계학술발표회
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• pp.28-28
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• 2017

• 한국토양비료학회지
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• 제36권1호
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• pp.41-49
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• 2003

물관리와 유기물 시용이 다른 논에서 메탄 배출을 측정하였다. 벼 식물체를 통해 배출되는 메탄을 측정하기 위하여 벼를 심은 chamber와 심지 않은 chamber를 반복으로 포장에 설치하였다. 기체시료는 벼 재배기간중 주 1회 채취하였다. 상시담수에서는 벼를 심은 NPK구, NPK(+P),는 $0.174g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였으나 심지 않은 NPK구, NPK(-P),는 $0.046g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였다. 벼를 심은 볏짚퇴비 시응구, RSC(+P), 는 $0.214g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였으나 심지 않은 볏짚퇴비 시용구, RSC(-P),는 $0.076g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였다. 볏짚을 2월에 시용하고 벼를 심은 시험구, RS2(+P), 는 $0.328g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였으나 볏짚을 2월에 시용하고 벼를 심지 않은 시험구, RS2(-P),는 $0.1g\;CH_4\;m^{-2}\;d^{-1}$의 배출을보였다. 볏짚을 5월에 시용하고 벼를 심은 시험구, RS5(+P). 는 $0.414g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였으나 볏짚을 2월에 시용하고 벼를 심지 않은 시험구, RS5(-P),는 $0.187g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였다. 간단관개에서는 NPK(+P)는 $0.115g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였으나 NPK(-P)는 $0.041g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였다. RSC(+P)는 $0.137g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였으나 RSC(-P)는 $0.06g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였다. RS2(+P) 는 $0.204g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였으나 RS2(-P)는 $0.09g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였다. RS2(+P)는 $0.273g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였으나 RS5(-P)는 $0.13g\;CH_4\;m^{-2}\;d^{-1}$의 배출을 보였다. 상시담수 처리에서 벼 식물체를 통한 메탄 수송은 NPK구, RSC구 (볏짚퇴비를 5월에 시용한 구), RS2구(볏짚을 2월에 시응한 구)와 RS5구 (볏짚을 5월에 시용한 구)에서 각기 73.6 %, 64.5%, 69.5%, 54.8%였었고 평균 65.6%였었다. 간단관개처리에서 벼 식물체를 통한 메탄 수송은 NPK구, RSC구, RS2구와 RS5구에서 각각 64.3, 59.2, 55.9, 52.4였다.

• 한국연소학회지
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• 제17권3호
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• pp.1-8
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• 2012

The CO emission characteristics of interacting hydrogen and methane partially premixed flames were numerically investigated. A counterflow geometry was introduced to establish interacting two partially premixed flames. An one-dimensional OPPDIF code was used to simulate the interacting flames. The GRI-v3.0 was used to calculate the chemical reactions. Emission index for CO(EICO) was evaluated to quantify the CO emitted from the interacting flames. The global strain rate and equivalence ratios for each flame(${\Phi}_{CH_4}$ and ${\Phi}_{H_2}$) were used as parameters to control the extent of interaction between two partially premixed flames. When ${\Phi}_{CH_4}$ was kept to stoichiometric condition and ${\Phi}_{H_2}$ was at rich condition, unburned H2 species of hydrogen flame was transported to the methane flame and affected reactions related with CO formation. When ${\Phi}_{CH_4}$ increased from a stoichiometry to rich condition while ${\Phi}_{H_2}$ was kept to stoichiometric condition, EICO increased initially, had a peak value at ${\Phi}_{CH_4}=1.5$ and decreased gradually. This could be elucidated with an analysis for the elementary reactions related with CO formation.

• 한국기후변화학회지
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• 제5권4호
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• pp.359-366
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• 2014

This research was conducted to estimate methane emission from paddy field of 16 local government levels using the DNDC(DeNitrification-DeComposition) model from 1990 to 2010. Four treatments used in DNDC model for methane emission calculations were (1) midseason drainage with rice straw, (2) midseason drainage without rice straw, (3) continuous flooding with rice straw, and (4) continuous flooding without rice straw. Methane emissions at continuous flooding with rice straw were the highest ($471kg\;C\;ha^{-1}$) while were the lowest ($187kg\;C\;ha^{-1}$) at midseason drainage without rice straw. The average methane emission for 21 years was the highest ($1,406Gg\;CO_{2-eq}$.) in Jeonnam province because of its large cultivation area. Jeju province had the highest the average methane emission per unit area due to the organic content in soil.

• 한국수소및신에너지학회논문집
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• 제18권1호
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• pp.75-84
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• 2007

The effects of hydrogen enrichment to methane on NOx formation have been investigated with swirl stabilized pre-mixed hydrogen enriched methane flame in a laboratory-scale pre-mixed combustor(nominally of 5,000 kcal/hr). The hydrogen enriched methane fuel and air were mixed in a pre-mixer and introduced to the combustor through different degrees of swirl vanes. The flame stability was examined for different amount of hydrogen addition to the methane fuel, different combustion air flow rates and swirl strengths by comparing equivalence ratio at the lean flame limit. The hydrogen addition effects and swirl intensity on the combustion characteristics of pre-mixed methane flames were examined using gas analyzers, and OH chemiluminescence techniques to provide information about species concentration of emission gases and flowfield. The results of NOx and CO emissions were compared with a diffusion flame type combustor. The results show that the lean stability limit depends on the amount of hydrogen addition and the swirl intensity. The lean stability limit is extended by hydrogen addition, and is reduced for higher swirl intensity at lower equivalence ratio. The addition of hydrogen increases the NOx emission, however, this effect can be reduced by increasing either the excess air or swirl intensity. The NOx emission of hydrogen enriched methane premixed flame was lower than the corresponding diffusion flame under the fuel lean condition.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.448-453
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• 2003

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 countermeasure 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($10{\sim}15%$).