• Journal of the Korean GEO-environmental Society
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• v.15 no.9
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• pp.5-12
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• 2014

Anaerobic digestion was investigated for the stabilization of sludge, decrease of volatile solids, production of biogas for wastewater sludge. In this study, total solids and volatile solids, elemental analysis were conducted to determine characteristics of various types of sludges and investigate the feasibility of biogas production of Municipal Wastewater Sludge (MWS), Industrial Wastewater Sludge (IWS), mixed sludge (Mix), and Municipal Wastewater Sludg Cake (MWSC). Total solids, volatile solids, and C/N ratio were determined in the range of 11.2~20.6 %, 62.1~83.1 % of TS and 4.96~8.33 %. Using the biochemical methane potential (BMP test), mixed sludge and wastewater sludge finished the methane production within approximately 20 day and 16~17 day. Sludge cake finished within 10 day. Mixed sludge produced 395.5 mL $CH_4$ per g of Volatile Solid (VS) and resulted in the highest methane production. For carbon dioxide production, five sludges had similar value of accumulated carbon dioxide production except for sludge cake.

• The Korea Swine Journal
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• v.12 no.7 s.131
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• pp.136-138
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• 1990

돈분 메탄발효시스템은 양돈장에서 흘러나오는 돈분뇨를 발효시켜 여기서 발생되는 가스를 이용, 발전기 터빈을 돌려 전력을 생산하고 남은 분뇨 찌꺼기는 탈수와 건조과정을 거쳐 양질의 유기질 비료를 생산할 수 있다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.181-184
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• 2006

We successfully completed the development test for a 10-ton thrust liquid rocket engine using LOX+LNG (Liquefied Natural Gas, or Methane) with a high performance turbopump system. Resulting from the success of the regenerative-cooling capability using LNG, high pressure-generating capability and gas-generating performance, etc, methane engine with the product name CHASE-10 will be commercialized in the near future.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.190.2-190.2
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• 2016

메탄은 변환을 통해 아세틸렌 및 수소와 같은 에너지 생산에 보다 유용한 기체를 얻을 수 있다. 메탄의 열분해 온도는 약 1,200 K로 알려져 있으며, 그 이상의 고온 환경 및 첨가물을 제공한 경우 효과적인 변환을 기대할 수 있다. 이러한 고온 환경 및 화학반응을 제공할 수 있는 시스템으로 열플라즈마 반응로가 있다. 일반적인 열플라즈마는 아크 방전이나 고주파 유도결합 방전으로 플라즈마 발생기에서 발생시킨 이온화된 열유체로 10,000 K 이상의 초고온과 최대 수천 m/s의 특성을 가지고 있다. 본 연구에서는 효율적인 메탄 변환을 위한 저전력 아크 플라즈마 발생기 및 반응로 내부의 온도 및 속도장을 전산모사하여 열유동 특성을 분석하였다. 아크 플라즈마 토치 영역의 전산해석은 전자기적 현상과 고온 열유동의 유체역학적 현상이 함께 작용하므로 기존에 사용되고 있는 전산유체 역학적인 방법론에 전자기적 현상에 대한 보존 방정식이 결합된 자기유체역학(Magnetohydrodynamic, MHD)방법을 이용하였고, 반응기 내부의 복잡한 열유동은 안정적인 계산이 가능한 상용 전산 유체역학(Computational Fluids Dynamics, CFD) 코드를 MHD 코드를 이용한 전산해석 결과 및 고온 물성치와 결합하여 해석하였다. 전산해석에 사용된 운전 변수로는 방전기체인 아르곤과 수소의 전체 유량을 45 L/min 으로 고정하고 수소의 비율을 0%, 6%, 12.5%, 20%로 하였으며, 각 유량 조건에서 입력 전력을 0.7 ~ 2.5 KW로 변화시켜 전체 15종의 운전조건에 따른 전산해석을 수행하여 각각의 운전변수에 따라 입력전력 기준 오차 1 ~ 28%에 해당하는 결과를 도출하였다. 본 연구를 통해 개발된 전산해석 방법을 이용하여 다양한 조건에서 아크 플라즈마 반응로 내부의 온도 및 속도장에 대한 전산해석 결과를 제시하였고, 효율적인 메탄 변환 공정을 개발하기 위한 아크 플라즈마 반응로의 설계조건 및 운전 조건을 제시할 수 있는 기반을 확보하였다.

• Journal of Wetlands Research
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• v.21 no.2
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• pp.95-101
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• 2019

In tidal flats that lack plants, methane ($CH_4$) fluxes are both positive (gas emission) and negative (gas "sinking") in nature. The levels of methanotroph populations significantly affect the extent of $CH_4$ sinking. This preliminary study examined $CH_4$ flux in tidal flats using a circular closed-chamber method to understand the effects of macroinvertebrate burrowing activity. The chamber was deployed over decapods (mud shrimp, Laomedia astacina and crab, Macrophthalmus japonicus) burrows for ~ 2 h, and the $CH_4$ and $CO_2$ concentrations were continuously monitored using a closed, diffuse $CH_4/CO_2$ flux meter. We found that Laomedia astacina burrow (which is relatively long) site afforded higher-level $CH_4$ production, likely due to diffusive emission of $CH_4$ in deep-layer sediments. In addition, the large methanotrophic bacteria population found in the burrow wall sediments has $CH_4$ oxidation (consumption) potential. Especially, nitrite-driven anaerobic oxidation of methane (AOM) may occur within burrows. The proposed $CH_4$-oxidation process was supported by the decrease in the ${\delta}^{13}C$ of headspace $CO_2$ during the chamber experiment. Therefore, macroinvertebrate burrows appear to be an important ecosystem environment for controlling atmospheric $CH_4$ over tidal flats.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.35-40
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• 1997

This study was conducted to investigate methane emission under different rice cultural practices in paddy soil (Jeonbug Series, occurring on fluvio-alluvial plain). The rates of application of fresh rice straw were 5,000kg/ha in combination with 110 and 160kg N/ha as chemical fertilizer. The methane emission among the rice cultural practices was in the order of transplanting cultivation, direct seeding on flooded surface and direct seeding on dry paddy field. The average methane flux was $10.27mg/m^2/h$ in direct, seeding on dry paddy field and $24.1mg/m^2/h$ in transplanting cultivation. The diurnal variation of methane emission at heading stage was high from 9 a.m. till 7 p.m. and the methane emission rate was highly correlated with air temperature fluctuation and soil Eh. The seasonal change of methane flux was high from ear formation stage to heading stage.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.4
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• pp.62-71
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• 2013

This study was carried out to develope a pre-treatment technology for anaerobic digestion. Breaking down large particles into smaller particles enhances the performance of anaerobic digestion by increasing the hydrolysis of particles. A degree of hydrolysis is the most important factor determining the overall efficiency of methane production. Three types of pre-treatment devices (blade-type crusher, ozonization system, cavitation system) were set up and operated to crush solids in pig slurry in order to enhance biodegradability. The effect of pre-treatment on decreasing granular size within pig slurry by three experimental devices were compared. The highest performance of granulization of pig slurry was attained in a combination of blade-type crusher and ozonization system. In batch experiment, there was an improvement of the methane potential by combined pretreatment with crusher and cavitation. In case of pre-treated slurry, biogas and methane production were 325.9 L and 59.7% respectively, while, in untreated slurry, the production were lower; 298.8 L and 55.7%, respectively. These results indicate that higher anaerobic digestion efficiency of pig slurry can be obtained through the pre-treatment.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.404-408
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• 2003

In this study, hydrogen gas produced by anaerobic mocrobial at anaerobic condition. To maintain the high MLSS concentration, anaerobic sludge was transformed to granular sluge by adding both high molecular cationic polymer(M.W>5,000,000) and silica sol. Hydrogen production was easily distributed, which seemed caused by methane producing microbial. Even low pH control(pH<5.5) was not the effective mean to block methane producing microbial. To decrease of $H_2$ production was closely related with the inclose of $CH_4$ production. Other mean expect for pH control must be devised for the efficient $H_2$ production.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.339-342
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• 2003

In this study , hydrogen gas produced by anaerobic mocrobial at anaerobic condition. To maintain the high MLSS concentration, anaerobic sludge was transformed to granular sluge by adding both high molecular cationic polymer(M.W.>5,000,000) and silica sol. Hydrogen production was easily distributed, which seemed caused by methane producing microbial. Even low pH control(pH<5.5) was not the effective mean to block methane producing microbial. To decrease of $H_2$ production was closely related with the inclose of $CH_4$ production. Other mean expect for pH control must be devised for the efficient $H_2$ production.

• Korean Journal of Ecology and Environment
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• v.51 no.2
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• pp.160-167
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• 2018

The role played by reservoirs in the biogeochemical cycles of elements is a subject of ongoing debate. Recent research has revealed that reservoirs emit significant levels of greenhouse gases. To assess the importance of reservoirs in monsoon climate areas as a source of methane gas into the atmosphere, we investigated variations in organic carbon (OC) input into the reservoir, oxic state changes, and finally the amount of methane emitted (focusing on the ebullition pathway) in Lake Soyang, which is the largest reservoir in South Korea. Total organic carbon (TOC) concentrations were higher during summer after two years of heavy rainfall. The sedimentation rates of particulate organic carbon (POC) and particulate organic nitrogen (PON) were higher in the epilimnion and hypolimnion than the metalimnioin, indicating that autochthonous and allochthonous carbon made separate contributions to the TOC. During stratification, oxygen depletion occurred in the hypolimnion due to the decomposition of organic matter. Under these conditions, $H_2S$ and $CH_4$ can be released from sediment. The methane emissions from the reservoir were much higher than from other natural lakes. However, the temporal and spatial variations of methane ebullition were huge, and were clearly dependent on many factors. Therefore, more research via a well-organized field campaign is needed to investigate methane emissions.