• 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.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.209-209
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• 2022

Reservoirs play a key role in the carbon cycle between terrestrial and marine systems and are pathways that release greenhouse gases(GHGs), CO₂, CH₄, and N₂O, into the atmosphere by decomposing organic matters. Developed countries have been actively conducting research on carbon emission assessment of dam reservoirs for over 10 years under the leadership of UNESCO/IHA, but associated research is very rare in Korea. In particular, the GHGs footprint evaluation, which calculates the change in net carbon emission considering the watershed environment between pre- and post- impoundment, is very important in evaluating the carbon emission of hydroelectric dams. The objective of this study was to estimate the GHG emissions and footprints in Daecheong Reservoir using the G-res Tool, an online platform developed by UNESCO/IHA. The G-res Tool estimates CO₂ and CH₄ emissions in consideration of diverse pathway fluxes of GHGs from the reservoir and characterizes changes in GHG fluxes over 100 years based on the expected lifetime of the dam. The input required to use the G-res Tool include data related to watersheds, reservoirs, and dams, and most were collected through the government's public portal. As a result of the study, the GHG footprint of Daecheong Reservoir was estimated to be 93 gCO₂eq/m²/yr, which is similar to that of other reservoirs around the world in the same climate zone. After impoundment, the CH₄ diffusion emission from the reservoir was 73 gCO₂eq/m²/yr, also similar to those of the overseas reservoirs, but the CH₄ bubbling emission, degassing emission, and CO₂ diffusion emissions were 44, 34, 252 gCO₂eq/m²/yr, respectively, showing a rather high tendency. Since the dam reservoir carbon footprint evaluation is essential for the Clean Development Mechanism evaluation of hydroelectric power generation, continuous research is needed in the future. In particular, experimental studies that can replace the emission factors obtained from the overseas dam reservoirs currently used in the G-res Tool should be promoted.

• 한국토양비료학회지
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• 제49권1호
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• pp.30-35
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• 2016

Rice cultivation in paddy field affects the global balance of methane ($CH_4$) as a key greenhouse gas. To evaluate a potential use of by-product gypsum fertilizer (BGF) in reducing $CH_4$ emission from paddy soil, $CH_4$ fluxes from a paddy soil applied with BGF different levels (0, 2, 4 and $8Mg\;ha^{-1}$) were investigated by closed-chamber method during rice cultivation period. $CH_4$ flux significantly decreased (p<0.05) with increasing level of BGF application. $8Mg\;ha^{-1}$ of BGF addition in soil reduced $CH_4$ flux by 60.6% compared to control. Decreased soil redox potential (Eh) resulted in increasing $CH_4$ emission through a $CO_2$ reduction reaction. The concentrations of dissolved calcium (Ca) and sulfate ion (${SO_4}^{2-}$) in soil pore water were significantly increased as the application rate of BGF increased and showed negatively correlations with $CH_4$ flux. Decreased $CH_4$ flux with BGF application implied that ${SO_4}^{2-}$ ion led to decreases in electron availability for methanogen and precipitation reaction of Ca ion with inorganic carbon including carbonate and bicarbonate as a source of $CH_4$ formation under anoxic condition. BGF application also increased rice grain yield by 16% at $8Mg\;ha^{-1}$ of BGF addition. Therefore, our results suggest that BGF application can be a good soil management practice to reduce $CH_4$ emission from paddy soil and to increase rice yield.

• 한국안전학회지
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• 제30권1호
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• pp.111-118
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• 2015

In this study, we carried out the emissions analysis of CO and $non-CO_2$ for the age-classes of various pine trees(Pinus koraiensis, Pinus densiflora, Pinus rigida Mill., Pinus thunbergii Parl.) to estimate of emission factors of the crown layer and surface layer in the forest fire. We used the thermal characteristic analyzer cone heater and NDIR analyzer in order to measure amount of emission. As a result, the major emissions of Pinus koraiensis were $CO_2$ and $CH_4$ and that of Pinus thunbergii Parl. was only CO. The major emissions of the most of pine trees were NO and $N_2O$. The $CO_2$ emission of Pinus thunbergii Parl. was the highest about as $7.26{\times}10^{-2}{\sim}1.63{\times}10^{-1}g$ and next came Pinus densiflora, Pinus koraiensis, Pinus rigida Mill.. And the CO emission of Pinus thunbergii Parl. was about $5.14{\times}10^{-3}{\sim}6.58{\times}10^{-3}g$ and followed by Pinus densiflora, Pinus koraiensis, Pinus rigida Mill.. The emissions of $CH_4$, NO, and $N_2O$ showed small differences between species and the emission of $CH_4$ was $8.37{\times}10^{-5}{\sim}2.55{\times}10^{-4}g$, and NO was $6.65{\times}10^{-5}{\sim}2.0{\times}10^{-4}g$ and $N_2O$ was $1.42{\times}10^{-4}{\sim}2.09{\times}10^{-3}g$ in all species. Particularly, the emission of Pinus thunbergii Parl. was the highest in all pine trees except $CH_4$.

• Asian-Australasian Journal of Animal Sciences
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• 제29권12호
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• pp.1805-1811
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• 2016

The goal of this study was to estimate the emissions of greenhouse gases (GHG), namely methane ($CH_4$), nitrous oxide ($N_2O$), and carbon dioxide ($CO_2$) from poultry and pig production in South Korea over the last 10 years (2005 through 2014). The calculations of GHG emissions were based on Intergovernmental Panel on Climate Change (IPCC) guidelines. Over the study period, the $CH_4$ emission from manure management decreased in layer chickens, nursery to finishing pigs and gestating to lactating sows, but there was a gradual increase in $CH_4$ emission from broiler chickens and male breeding pigs. Both sows and nursery to finishing pigs were associated with greater emissions from enteric fermentation than the boars, especially in 2009. Layer chickens produced lower direct and indirect $N_2O$ emissions from 2009 to 2014, whereas the average direct and indirect $N_2O$ emissions from manure management for broiler chickens were 12.48 and $4.93Gg\;CO_2-eq/yr$, respectively. Annual direct and indirect $N_2O$ emissions for broiler chickens tended to decrease in 2014. Average $CO_2$ emission from direct on-farm energy uses for broiler and layer chickens were 46.62 and $136.56Gg\;CO_2-eq/yr$, respectively. For pig sectors, the $N_2O$ emission from direct and indirect sources gradually increased, but they decreased for breeding pigs. Carbon dioxide emission from direct on-farm energy uses reached a maximum of $53.93Gg\;CO_2-eq/yr$ in 2009, but this total gradually declined in 2010 and 2011. For boars, the greatest $CO_2$ emission occurred in 2012 and was $9.44Gg\;CO_2-eq/yr$. Indirect $N_2O$ emission was the largest component of GHG emissions in broilers. In layer chickens, the largest contributing factor to GHG emissions was $CO_2$ from direct on-farm energy uses. For pig production, the largest component of GHG emissions was $CH_4$ from manure management, followed by $CO_2$ emission from direct on-farm energy use and $CH_4$ enteric fermentation emission, which accounted for 8.47, 2.85, and $2.82Gg-CO_2/yr$, respectively. The greatest GHG emission intensity occurred in female breeding sows relative to boars. Overall, it is an important issue for the poultry and pig industry of South Korea to reduce GHG emissions with the effective approaches for the sustainability of agricultural practices.

• 대한기계학회논문집B
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• 제29권2호
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• pp.263-270
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• 2005

An experimental study was performed to investigate the effects of partially premixing, varying the equivalence ratios from $0.79{\sim}{\infty}$, on NOx emissions and chemiluminescence of excited $OH^{\ast},\;CH^{ast}\;C_2^{\ast}$ radicals in laminar partially premixed flames. the signal from the electronically excited state of $OH^{\ast},\;CH^{ast}\;C_2^{\ast}$ was detected through a band pass filter with a photo multiplier tube, which are processed to the intensity ratio ($C_2^{\ast}/CH^{\ast},\;C_2^{\ast}/OH^{\ast},\;and\;CH^{\ast}/OH^{\ast}$) to reveal the correlation with local equivalence ratio. And measurements of NOx emission were made to investigate the relationship between visible flame appearance, chemiluminescence, and EINOX. The results demonstrated that (1) the flames at ${\phi}<1.59$ exhibited classical double flame structure, at ${\phi}>4.76$, the flames exhibited diffusion flame structure, and the intermediate flames at $1.59<{\phi}<4.76$ was a merged flame, (2) the $OH^{\ast}$ peak was located inside the $CH^{\ast}\;and\;C_2^{\ast}$ radical for all measured conditions and the emission intensity ratio of $C_2^{\ast}/CH^{\ast}\;and\;C_2^{\ast}/OH^{\ast}$ were identified as good marker for local equivalence ratio over a range of ${\phi}=0.79{\sim}1.2\;and\;CH^{\ast}/OH^{\ast}\;is\;0.79<{\phi}<1.9$. However, it was difficult to predict the equivalence ratio in partially premixed flames using this system for ${\phi}>2.38$, (3) the minimum NOX emission index (EINOx) is obtained for a equivalence ratio of 3.19 in the intermediate flames.

• 한국대기환경학회지
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• 제27권4호
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• pp.443-453
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• 2011

Real-time Traffic Information Service could play a key role in reducing incomplete combustion time remarkably since it can provide traffic information in real-time basis. Emission characteristics of test engines were studied in terms of travel distance and speed. The present study focused on a north district in Daegu, 12 km. The driving for the emission test was done at 8AM, 3PM, 7PM which represents various traffic conditions. The reduced emissions of Greenhouse Gases (GHG) have been measured for a travel distance running at different loads (conventional shortest route and Real-time Traffic Information) and GHG ($CO_2$, $CH_4$, $N_2O$) are all inventoried and calculated in terms of existing emission factors. The emission of GHG has been shown to reduce linearly with travel distance: $CO_2$ (9.15%), $CH_4$ (18.43%), $N_2O$(18.62%).

• Membrane and Water Treatment
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• 제8권2호
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• pp.171-184
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• 2017

This study presents the effect of hydraulic retention time (HRT) on the characteristics of emission of three major greenhouse gases (GHGs) including $CH_4$, $CO_2$ and $N_2O$ during operation of a sequencing batch reactor for aerobic oxidation of methane with denitrification (AeOM-D SBR). Dissolved $N_2O$ concentration increased, leveled-off and slightly decreased as the HRT increased from 0.25 to 1d. Concentration of the dissolved $N_2O$ was higher at the shorter HRT, which was highly associated with the lowered C/N ratio. A longer HRT resulted in a higher C/N ratio with a sufficient carbon source produced by methanotrophs via methane oxidation, which provided a favorable condition for reducing $N_2O$ formation. With a less formation of the dissolved $N_2O$, $N_2O$ emission rate was lower at a longer HRT condition due to the lower C/N ratio. Opposite to the $N_2O$ emission, emission rates of $CH_4$ and $CO_2$ were higher at a longer HRT. Longer HRT resulted in the greater total GHGs emission as $CO_2$ equivalent which was doubled when the HRT increased from 0.5d to 1.0 d. Contribution of $CH_4$ onto the total GHGs emission was most dominant accounting for 98 - 99% compared to that of $N_2O$ (< 2%).

• 한국농림기상학회지
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• 제17권2호
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• pp.173-181
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• 2015

본 연구는 보리-벼 이모작 작부체계의 논 생태계에 설치한 개방형 $CO_2$ 플럭스시스템과 자동개폐식 챔버형 $CH_4$ 측정시스템에서 관측된 탄소관련 온실가스 자료와 작물 생장량자료를 활용하여 논 생태계의 연간(2012.10.20~2013.10.21) 탄소수지를 분석하였다. 결론적으로 농작물의 생육인자와 환경인자는 $CO_2$의 순 생태계교환량(NEE)에 영향을 주는 것으로 분석되었고, $CH_4$ 배출량은 영농활동(특히 물관리)에 따라 큰 영향을 받는 것으로 분석되었다. 2012~2013년 벼-보리 이모작 작부체계의 논 생태계에서 보리 재배기간에는 단위면적($m^2$)당 100.2g의 탄소를 흡수하고 벼 재배기간에는 $m^2$당 374.1g의 탄소를 흡수하였지만, 휴경기간에는 토양호흡의 형태로 $m^2$당 41.2g의 탄소를 배출하여 연간 총 $433.1g\;m^{-2}$의 탄소를 흡수하는 것으로 분석되었다. 여기에 농작물의 수확에 따른 논 생태계의 탄소 배출량과 $CH_4$ 형태로배출되는 탄소량을 포함한 연간 순생물상생산량(NBP)은 $184.7g\;C\;m^{-2}$으로 추정되어, 보리-벼 이모작 작부체계의 논 생태계는 탄소 발원인 것으로 평가되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권3호
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• pp.439-446
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• 2014

Many studies on methane ($CH_4$) and nitrous oxide ($N_2O$) emissions from livestock industries have revealed that livestock production directly contributes to greenhouse gas (GHG) emissions through enteric fermentation and manure management, which causes negative impacts on animal environment sustainability. In the present study, three essential values for GHG emission were measured; i.e., i) maximum $CH_4$ producing capacity at mesophilic temperature ($37^{\circ}C$) from anaerobically stored manure in livestock category ($B_{0,KM}$, Korean livestock manure for $B_0$), ii) $EF_{3(s)}$ value representing an emission factor for direct $N_2O$ emissions from manure management system S in the country, kg $N_2O-N$ kg $N^{-1}$, at mesophilic ($37^{\circ}C$) and thermophilic ($55^{\circ}C$) temperatures, and iii) $N_{ex(T)}$ emissions showing annual N excretion for livestock category T, kg N $animal^{-1}$ $yr^{-1}$, from different livestock manure. Static incubation with and without aeration was performed to obtain the $N_2O$ and $CH_4$ emissions from each sample, respectively. Chemical compositions of pre- and post- incubated manure were analyzed. Contents of total solids (% TS) and volatile solid (% VS), and the ratio of carbon to nitrogen (C/N) decrease significantly in all the samples by C-containing biogas generation, whereas moisture content (%) and pH increased after incubation. A big difference of total nitrogen content was not observed in pre- and post-incubation during $CH_4$ and $N_2O$ emissions. $CH_4$ emissions (g $CH_4$ kg VS-1) from all the three manures (sows, layers and Korean cattle) were different and high C/N ratio resulted in high $CH_4$ emission. Similarly, $N_2O$ emission was found to be affected by % VS, pH, and temperature. The $B_{0,KM}$ values for sows, layers, and Korean cattle obtained at $37^{\circ}C$ are 0.0579, 0.0006, and 0.0828 $m^3$ $CH_4$ kg $VS^{-1}$, respectively, which are much less than the default values in IPCC guideline (GL) except the value from Korean cattle. For sows and Korean cattle, $N_{ex(T)}$ values of 7.67 and 28.19 kg N $yr^{-1}$, respectively, are 2.5 fold less than those values in IPCC GL as well. However, $N_{ex(T)}$ value of layers 0.63 kg N $yr^{-1}$ is very similar to the default value of 0.6 kg N $yr^{-1}$ in IPCC GLs for National greenhouse gas inventories for countries such as South Korea/Asia. The $EF_{3(s)}$ value obtained at $37^{\circ}C$ and $55^{\circ}C$ were found to be far less than the default value.