• 제목, 요약, 키워드: Methane

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Net Methane Oxidation Performance of Anaerobic Sewage Sludge

  • Yi, Taewoo;Kim, Tae Gwan;Lee, Eun-Hee;Lee, Jung-Hee;Cho, Kyung-Suk
    • Journal of Microbiology and Biotechnology
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    • v.22 no.10
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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.

Advanced estimation and mitigation strategies: a cumulative approach to enteric methane abatement from ruminants

  • Islam, Mahfuzul;Lee, Sang-Suk
    • Journal of Animal Science and Technology
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    • v.61 no.3
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    • pp.122-137
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    • 2019
  • Methane, one of the important greenhouse gas, has a higher global warming potential than that of carbon dioxide. Agriculture, especially livestock, is considered as the biggest sector in producing anthropogenic methane. Among livestock, ruminants are the highest emitters of enteric methane. Methanogenesis, a continuous process in the rumen, carried out by archaea either with a hydrogenotrophic pathway that converts hydrogen and carbon dioxide to methane or with methylotrophic pathway, which the substrate for methanogenesis is methyl groups. For accurate estimation of methane from ruminants, three methods have been successfully used in various experiments under different environmental conditions such as respiration chamber, sulfur hexafluoride tracer technique, and the automated head-chamber or GreenFeed system. Methane production and emission from ruminants are increasing day by day with an increase of ruminants which help to meet up the nutrient demands of the increasing human population throughout the world. Several mitigation strategies have been taken separately for methane abatement from ruminant productions such as animal intervention, diet selection, dietary feed additives, probiotics, defaunation, supplementation of fats, oils, organic acids, plant secondary metabolites, etc. However, sustainable mitigation strategies are not established yet. A cumulative approach of accurate enteric methane measurement and existing mitigation strategies with more focusing on the biological reduction of methane emission by direct-fed microbials could be the sustainable methane mitigation approaches.

레이저메탄검지기를 활용한 폐기물매립지 표면발생량 산정에 관한 연구 (Estimation of Methane Emission Flux Using a Laser Methane Detector at a Solid Waste Landfill)

  • 강종윤;박진규;이남훈
    • 유기물자원화
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    • v.23 no.3
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    • pp.78-84
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    • 2015
  • 본 연구에서는 표면 메탄농도와 지구통계기법(거리역산가중기법)을 기초로 표면 메탄발산량을 평가하고자 하였다. 실험결과 표면 메탄농도는 표면 메탄발산량과 높은 상관성이 있는 것으로 나타나, 표면 메탄농도를 기초로 표면 메탄발산량을 산정하는 것이 가능한 것으로 나타났다. 또한 지구통계기법 적용 결과 측정 면적의 12.85%가 총 메탄발산량의 42.21%를 나타내어 챔버 방법으로 메탄발산량을 정확하게 평가하기 위해서는 지구통계기법을 반드시 적용해야 하는 것으로 사료된다.

Biocatalytic Conversion of Methane to Methanol as a Key Step for Development of Methane-Based Biorefineries

  • Hwang, In Yeub;Lee, Seung Hwan;Choi, Yoo Seong;Park, Si Jae;Na, Jeong Geol;Chang, In Seop;Kim, Choongik;Kim, Hyun Cheol;Kim, Yong Hwan;Lee, Jin Won;Lee, Eun Yeol
    • Journal of Microbiology and Biotechnology
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    • v.24 no.12
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    • pp.1597-1605
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    • 2014
  • Methane is considered as a next-generation carbon feedstock owing to the vast reserves of natural and shale gas. Methane can be converted to methanol by various methods, which in turn can be used as a starting chemical for the production of value-added chemicals using existing chemical conversion processes. Methane monooxygenase is the key enzyme that catalyzes the addition of oxygen to methane. Methanotrophic bacteria can transform methane to methanol by inhibiting methanol dehydrogenase. In this paper, we review the recent progress made on the biocatalytic conversion of methane to methanol as a key step for methane-based refinery systems and discuss future prospects for this technology.

Short Review of Global Methane Situation and of Facilities to Reduce in Ruminants in Third Wol1d Countries

  • Islam, M.R.;Begum, J.
    • 아세아태평양축산학회지
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    • v.10 no.2
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    • pp.157-163
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    • 1997
  • This paper analyses a number of important areas relating to methane production in ruminants, consequent hazards and different methods of reducing this gas. Clearly methane not only affects on the environment but also on the economy of animal production. Several factors including feed, species, microbes, rumen environment, etc. are responsible for methane production in animals. Although methane production can be reduced by chemical manipulation, defaunation and strategic feeding, the latter was found to be effective because the method is easier to follow than the others. Furthermore, feeding technology could play an important role in reducing methane production particularly in developing countries because of its relative cost effectiveness. however, it needs to compare to what extent it could reduce methane production as well as cost of animal production. Therefore, research program needs to be concentrated on the appropriate feeding system to reduce methane production, consequently pollution and cost of production particularly in developing countries.

Methane Emissions from Dry Cows Fed Grass or Legume Silage

  • Kasuya, Hirotaka;Takahashi, Junichi
    • 아세아태평양축산학회지
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    • v.23 no.5
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    • pp.563-566
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    • 2010
  • Using an open-circuit system, we compared the methane ($CH_4$) emission from dry cows fed first-cut Timothy silage ($1^{st}$ TY), second-cut Timothy silage ($2^{nd}$ TY), second-cut Italian ryegrass silage ($2^{nd}$ IR), third-cut Italian ryegrass silage ($3^{rd}$ IR), or second-cut red clover silage ($2^{nd}$ RC) as the sole feed. The methane emission ranged from 258.2 L $day^{-1}$ to 396.5 L $day^{-1}$. The methane emission from dry cows fed red clover silage was relatively lower than that from dry cows fed grass silage. However, the methane emission per unit digestible neutral detergent fiber (NDF) intake (dNDFI) did not differ significantly between the experimental silages. The methane emission was significantly correlated with the NDF intake and digestibility. Methane emission had a significant correlation with the quadratic function of dNDFI. The differences in the daily volume of methane emission from cows fed different forages can be explained by dNDFI.

Novel multi-scale diffusion model for catalytic methane combustion

  • Huang, Kai;Wang, Lianguang;Xu, Yang;Wu, Dongfang
    • The Korean Journal of Chemical Engineering
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    • v.34 no.5
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    • pp.1366-1376
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    • 2017
  • A multi-scale model of methane catalytic combustion was built by a series of balance equations and diffusion equations, and these equations were solved through the computational fluid dynamics (CFD) software. The difference between this work and previous model is the diffusion process in catalyst coating was considered. By analyzing the methane conversion, temperature distribution and mass fraction contours of every component, the performance of multi-scale model was compared with that of the pure CFD model without diffusion. The effects of diffusion, methane concentration, flow rate on the methane conversion and temperature distribution of monolithic reactor were also evaluated and discussed by the multi-scale model. The multi-scale model showed better accuracy than the pure CFD model without diffusion process. Different methane concentrations and gas flow rates had enormous effects on the methane conversion and temperature. Therefore, it was beneficial to the reaction process to adjust the methane concentration and gas flow rate appropriately.

Effects of cultivation methods on methane emission in rice paddy

  • Kim, Sukjin;Choi, Jong-Seo;Kang, Shin-gu;Park, Jeong-wha;Yang, Woonho
    • 한국작물학회:학술대회논문집
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    • pp.319-319
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    • 2017
  • Methane is the main greenhouse gas released from rice paddy field. Methane from paddy fields accounts for 11 % of the global total methane emission. The global warming potential (GWP) of methane is 25 times more than that of carbon dioxide on a mass basis. It is well known that most effective practice to mitigate methane in paddy is related to the water management during rice growing season and the use of organic matters. This study was conducted to investigate the effects of tillage and cultivation method on methane emission in paddy. Tillage (tillage and no-tillage) and cultivation methods (transplanting and direct seeding) were combined tillage-transplanting (T-T), tillage-wet hill seeding (T-W), tillage-dry seeding (T-D) and no-till dry seeding (NT-D) to evaluate methane mitigation efficiency. Daily methane emission was decreased on seeding treatments (T-W, T-D, NT-D) than transplanting treatment (T-T). Amount of methane emission during rice growing season is highest in T-T ($411.7CH_4\;kg\;ha^{-1}y^{-1}$) and lowest in NT-D treatment (89.7). In T-W and T-D treatments, methane emissions were significantly decreased by 36 and 51 % respectively compared with T-T. Methane emissions were highly correlated with the dry weight of whole rice plant ($R^2=0.62{\sim}0.93$). T-T treatment showed highest $R^2$ (0.93) among the four treatments. Rice grain yields did not significantly differ with the tillage and cultivation methods used. These results suggest that direct seeding practice in rice production could mitigate the methane emissions without loss in grain yield.

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Predicting the Methane Gas Generation Rate at Landfill Sites Using the Methane Gas Generation Rate Constant (k)

  • Chung, Jin-Do;Kim, Jung-Tae
    • Asian Journal of Atmospheric Environment
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    • v.2 no.2
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    • pp.116-124
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    • 2008
  • In this study, the Tier 2 method recommended by the Intergovernmental Panel on Climate Change (IPCC) was used to predict the methane generation rate at two landfill sites, designated as Y and C for purposes of this study, in South Korea. Factors such as the average annual waste disposal, methane emissions ($L_0$) and methane gas generation rate constant (k) were estimated by analyses of waste and the historical data for the landfills. The value of k was estimated by field experiments and then the changes in the methane generation rate were predicted through the year 2050, based on the value of k. The Y landfill site, which was in operation until the year 2008, will generate a total of 17, 198.7 tons by the end of 2018, according to our estimations. At the C landfill site, which will not be closed until the end of 2011, the amount of methane gas generated in 2011 will be 3,316 tons and the total amount of gas generated by 2029 will be 61,200 tons. The total production rate of methane gas at the C landfill is higher than that of the Y landfill. This indicates that the capacity of a landfill site affects the production rate of methane gas. However, the interrelation between the generation rate of methane and the value of k is weak. In addition, the generation of methane gas does not cease even when the operations at a landfill site come to a close and the methane gas production rate is at its highest at end of the operating life of a landfill site.

바이오가스로부터 온실가스 메탄 회수를 위한 3단 분리막 공정 모사 (Simulation on Recovery of Methane Greenhouse Gas from Biogas Using 3 Stage Membrane Modules)

  • 이용택
    • 멤브레인
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    • v.28 no.4
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    • pp.243-251
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    • 2018
  • 메탄은 중요한 온실가스 중의 하나이며, 바이오가스의 주 성분이다. 이러한 바이오가스로부터 메탄의 몰분율 농도를 0.95 이상으로 회수하기 위하여 폴리설폰 중공사 분리막 모듈을 3단으로 연결하여 회수율을 99% 이상으로 얻을 수 있도록 공정을 설계하고 전산 모사하였다. 수치 해석 시 이산화탄소 투과도와 선택도를 이산화탄소의 부분증기압 함수로 나타내어 전산 모사를 수행하여 정확도를 높이고자 하였다. 공급 기체 압력, 공급 기체 내 메탄 농도, 그리고 분리막 모듈 내 분리막 면적이 클수록, 생성물 내 메탄 몰분율 농도가 증가함을 알 수 있었다. 그러나 생성물 내 메탄 몰분율 농도를 0.95 이상, 동시에 메탄 회수율을 99% 이상 얻기 위해서는 분리막 모듈의 분리막 면적을 적절히 선택하여야 하며, 선정된 분리막 모듈을 다단 공정으로 구성함에도 불구하고 공급 기체 압력, 공급 기체 유속, 그리고 공급 기체 메탄 농도를 제한적 범위 내에서 조절하여야 함을 알 수 있었다.