• Title/Summary/Keyword: methane decomposition

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철광석 이용한 메탄 열분해 반응특성 (Characteristics of Thermal Decomposition of Methane Using Ore)

  • 이지윤;김아람;심동선;장현태
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2008년도 춘계학술발표논문집
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    • pp.319-322
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    • 2008
  • 본 논문은 미분 반응기 및 유동층반응기에서 메탄의 열분해에 의한 수소 생산과 탄소 생성에 대한 연구를 수행하였다. 일반적으로 고온 분해시 사용되는 니켈과 철 성분을 대신할 철광석을 이용하여 분해특성을 고찰하였다. 환경에 대한 영향을 최소화한 상태에서 메탄의 전환반응을 메탄 분해촉매 활성에 영향을 미치는 인자에 대하여 연구하였다. 측정된 압력요동특성치의 해석을 통하여 유동층 열분해촉매의 유동화현상을 측정하였으며, 유동화특성에 따른 메탄열분해능을 측정하였다. 또한 고정층에서 공간속도, 입자크기, 비표면적이 미치는 영향을 고찰하여 철광석의 사용가능성을 타진하였다.

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폴리이미드의 합성과 필름의 물성에 미치는 디아민과 용매의 효과 (The Effect of Diamine and Solvent on The Synthesis of Polyimides and Their Film Properties)

  • 최형기;이호식;정창남;김점식
    • 공업화학
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    • 제2권3호
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    • pp.253-261
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    • 1991
  • 폴리이미드의 전구체인 폴리아믹산을 benzophenone tetracarboxylic dianhydride (BTDA)와 4, 4'-diamino diphenyl methane (MDA) 혹은 MDA와 3, 3'-dimethyl benzidine (OTB)의 혼합디아민과 용액축중합반응에 의하여 합성하였다. 반응용매로는 m-cresol과 m-cresol/xylene의 혼합용매를 사용하였다. TGA 분석 결과 폴리이미드 필름은 초기분해 온도가 $540^{\circ}C-590^{\circ}C$의 범위로서 내열성이 우수하였다. DSC 분석으로 중합체의 유리전이온도는 $340^{\circ}$ 이상임을 확인하였다. 폴리이미드 필름은 양호한 기계적, 전기적 물성값을 갖는 시료에서 인장강도가 $16Kg/mm^2$ 이상이었고, 절연파괴전압이 200 KV/mm 정도였다. 대체로 MDA 만을 디아민으로 사용한 단일중합체보다 MDA/OTB 공중합체의 물성이 우수하였고, m-cresol에서 합성한 중합체보다 m-cresol/xylene 혼합용매계에서 합성한 중합체의 물성값이 우수하였다.

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돼지 사체의 혐기적 고온 매몰퇴비화법에서의 악취발생 특성 (Odor emission characteristics in anaerobic high temperature burial composting of swine carcasses)

  • 양우영;이진영;최연주;류희욱;채정석;전준민
    • 실내환경 및 냄새 학회지
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    • 제16권2호
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    • pp.187-198
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    • 2017
  • It is very important to treat infected livestock carcasses safely and quickly. In this study, the degradation characteristics and odor generation characteristics of carcasses were investigated during the treatment of swine carcasses using the anaerobic burial composting method. While the carcasses were decomposed, the temperature remained high, at $40{\sim}55^{\circ}C$ on average, and most of the carcasses were decomposed rapidly. The major odor-contributing substances in the buried composting method are sulfuric odor substances such as $H_2S$, $CH_3SH$, dimethyl sulfide (DMS) and dimethyl disulfide (DMDS), and the odor contribution of these substances is 93~99%. Among them, $CH_3SH$, which accounts for about 56~89% of odor contribution, was the most representative indicator substance. Despite the anaerobic digestion process, the methane concentration in the digestion process was as low as 0.5~0.8% at the burial point of the carcass. The odor and methane produced during the decomposition of the carcasses decreased considerably during the discharge to the surface layer through the buried layer consisting of compost. These results suggest that anaerobic high temperature burial composting is one of the most useful methods to treat carcasses of infected livestock.

건설폐기물 분리매립 및 생활폐기물과의 혼합매립에 의한 매립가스 발생 특성 (Characteristics of Landfill Gas Generation by Separate Landfill of Construction Waste and Mixed Landfill with Household Waste)

  • 박종근;천승규
    • 신재생에너지
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    • 제18권4호
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    • pp.1-11
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    • 2022
  • Landfill gas (LFG) generation characteristics in a construction waste landfill zone (block E) and mixed landfill zone (block A) were analyzed. During the period from October 2018 to April 2022, a total of 936×103 and 1,001×103 tons of waste were disposed in block E and block A, respectively. Out of this, 27.1% and 55.6% were biodegradable waste in block E and block A, respectively. The landfill masses of the two blocks were converted to be comparable. Then, the biodegradable waste and organic carbon were estimated by element analysis, biodegradable carbon by biochemical methane potential experiment (DC), and sulfate ion by acid decomposition. Results showed that biodegradable waste, organic carbon, biodegradable carbon, and sulfate ions in block A were 2.1, 1.6, 5.2, and 0.4 times greater than those in block E, respectively. The amount of LFG generated by block A was 4.8 times greater than that by block E. The average concentrations of methane (CH4) were 60.8% and 60.9% in block E and block A, respectively, which were unrelated to the nature of disposed waste. The average concentrations of hydrogen sulfide (H2S) were significantly high in block E (4,489 ppm) and block A (8,478 ppm). As the DC/SO42- of block E and block A were 0.35 and 4.56, respectively, increase in DC/SO42- caused increase in not only the total amount but also the concentration of H2S generated.

Multi-environment Trial Analysis for Yield-related Traits of Early Maturing Korean Rice Cultivars

  • Seung Young Lee;Hyun-Sook Lee;Chang-Min Lee;Su-Kyung Ha;Youngjun Mo;Ji-Ung Jeung
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2022년도 추계학술대회
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    • pp.252-252
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    • 2022
  • Genotype-by-environment interaction (GEI) refers to the comparative response of genotypes to different environments conditions. Thus, understanding GEI is a fundamental component for selecting superior genotypes for breeding programs. The significance of utilizing early maturing cultivars not only provides flexibility in planting dates, but also serves as an effective strategy to reduce methane emission from the paddy fields. In this study, we conducted multi-environment trials (METs) to evaluate yield-related traits such as culm length, panicle length, panicle number, spikelet per plant, and thousand grain weight. A total of eighty-one Korean commercial rice cultivars categorized as early maturing cultivars, were cultivated in three regions, two planting seasons for two years. The genotype main effect plus genotype-by-environment interaction (GGE) biplot analysis of yield-related traits and grain yield explained 70.02-91.24% of genotype plus GEI variation, and exhibited various patterns of mega-environment delineation, discriminating ability, representativeness, and genotype rankings across the planting seasons and environments. Moreover, simultaneous selection using weighted average of absolute scores from the singular value decomposition (WAASB) and multi-trait stability index (MTSI) revealed six highly recommended genotypes with high stability and crop productivity. The winning genotypes under specific environment can be utilized as useful genetic materials to develop regional specialty cultivars, and recommended genotypes can be used as elite climate-resilient parents to improve yield-potential and reduce methane emission as part to accomplish carbon-neutrality.

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Impacts of Unsystematic Solid Waste Dumping on Soil Properties and Climate Change

  • Benish ZAHRA;Farida BEGUM;Woo-Taeg KWON;Seung-Jun WOO;Min-Jae JUNG
    • 웰빙융합연구
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    • 제7권3호
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    • pp.31-42
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    • 2024
  • Purpose: Open-air dumping is a significant problem in Gilgit City, with limited research analyzing waste generation and its physicochemical impact on the soil. This study aimed to evaluate the effects of open dumping on soil properties and compare them with a controlled site. Research Design, data, and Methodology: Using ANOVA, the study found significant differences in electrical conductivity (EC), soil organic matter (SOM), soil organic carbon (SOC), sand, silt, and clay between the two sites, except for pH. Pearson correlation revealed that pH negatively correlated with EC, sand, and silt, but positively with SOM, SOC, and clay. The control site's mean EC was 6.06 mS/m, whereas the dumping site recorded 8.5 mS/m. EC is inversely related to SOM, SOC, silt, and clay, but directly to sand. SOC and SOM values varied significantly, with notable differences in soil texture components like clay and silt. Results: The research highlights the detrimental effects of unsystematic waste dumping on soil health and its contribution to greenhouse gas emissions, particularly methane, which exacerbates climate change. Conclusion: The study concluded that waste deposition and decomposition significantly impact EC, SOM, SOC, and soil texture, though pH remains unchanged. The unsystematic dumping of solid waste contributes to climate change through methane production, a potent greenhouse gas. To mitigate these impacts, the study recommends regular monitoring, waste prevention, recycling strategies, and continuous training for stakeholders to achieve sustainable development.

Production of Hydrogen and Carbon Nanotubes from Catalytic Decomposition of Methane over Ni:Cu/Alumina Modified Supported Catalysts

  • Hussain, Tajammul;Mazhar, Mohammed;Iqbal, Sarwat;Gul, Sheraz;Hussain, Muzammil;Larachi, Faical
    • Bulletin of the Korean Chemical Society
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    • 제28권7호
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    • pp.1119-1126
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    • 2007
  • Hydrogen gas and carbon nanotubes along with nanocarbon were produced from commercial natural gas using fixed bed catalyst reactor system. The maximum amount of carbon (491 g/g of catalyst) formation was achieved on 25% Ni, 3% Cu supported catalyst without formation of CO/CO2. Pure carbon nanotubes with length of 308 nm having balloon and horn type shapes were also formed at 673 K. Three sets of catalysts were prepared by varying the concentration of Ni in the first set, Cu concentration in the second set and doping with K in the third set to investigate the effect on stabilization of the catalyst and production of carbon nanotubes and hydrogen by copper and potassium doping. Particle size analysis revealed that most of the catalyst particles are in the range of 20-35 nm. All the catalysts were characterized using powder XRD, SEM/EDX, TPR, CHN, BET and CO-chemisorption. These studies indicate that surface geometry is modified electronically with the formation of different Ni, Cu and K phases, consequently, increasing the surface reactivity of the catalyst and in turn the Carbon nanotubes/H2 production. The addition of Cu and K enhances the catalyst dispersion with the increase in Ni loadings and maximum dispersion is achieved on 25% Ni: 3% Cu/Al catalyst. Clearly, the effect of particle size coupled with specific surface geometry on the production of hydrogen gas and carbon nanotubes prevails. Addition of K increases the catalyst stability with decrease in carbon formation, due to its interaction with Cu and Ni, masking Ni and Ni:Cu active sites.

예혼합 화염 날림 메커니즘에 음향 가진이 미치는 영향에 대한 실험적 연구 (An Experimental Study of Acoustic Excitation Effect on Blowoff Mechanism for Premixed Flame)

  • 신재익;정찬영;윤영빈
    • 한국항공우주학회지
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    • 제42권12호
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    • pp.1004-1012
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    • 2014
  • 본 연구에서는 보염기가 장착된 덕트형 연소기에 음향 가진을 주었을 때 화염의 날림 현상을 이해하기 위한 실험을 수행하였다. 화염 구조를 관측하기 위한 촬영기법으로는 $OH^*$ 자발광이 적용되었고 POD (Proper Orthogonal Decomposition) 알고리즘을 이용하여 이미지를 분석하였다. 연료는 메탄이 주 성분인 도시가스를 사용했으며 당량비를 낮춤으로써 화염 날림이 발생하도록 하였다. 공기 공급 유량, 가진 주파수 및 음압에 변화를 주며 실험을 하여 화염 날림이 발생하는 당량비를 측정하였다. 실험 조건에 따라 화염 날림 당량비 값이 크게 달랐으며 이러한 당량비 값에 변화를 주는 요인은 보염기 후류의 와류 주파수와 연소기 공진 효과의 영향으로 판단된다.

이산화탄소와 알코올류의 혼합물에 대한 방사선 분해반응에 관한 연구 (Gamma-Radiolysis of Carbon Dioxide (V). Radiolysis of Carbon Dioxide-Alcohol Mixtures)

  • 최상업;변형직;진준하
    • 대한화학회지
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    • 제35권1호
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    • pp.3-15
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    • 1991
  • 10 torr의 기체 iso-프로필알코올과 0∼1990 torr의 이산화탄소의 혼합기체에 0∼50 kGy의 Co-60감마선을 조사한 후 생성물을 기체크로마토그래프로 분석하여 일산화탄소, 아세톤, 메탄, 에탄, C$_3$H$_a$, C$_4$H$_b$ 및 tert-부틸알코올 등이 생성됨을 알았다. 490 torr 이상의 이산화탄소가 혼합된 시료에서는 G(CO)값 약 4를 얻었다. 아세톤 등 각 유기생성물의 생성속도와 iso-프로필알코올의 분해속도는 이산화탄소의 압력에 비례하여 증가되었는데, 이산화탄소 압력 10 torr 증가당 G-(-iso-Propanol)값은 4, G(Acetone)값은 2씩 증가되었다. 본 실험의 결과를 토대로 iso-프로필알코올과 이산화탄소 혼합기체에서의 방서선에 의한 일산화탄소와 각종 유기물의 생성반응 및 iso-프로필알코올의 분해반응 메카니즘을 고찰하였다.

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버섯 폐배지의 생화학적 메탄퍼텐셜 분석 (Biochemical Methane Potential Analysis of Mushroom Waste Medium)

  • 김창규;이준형;윤영만
    • 유기물자원화
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    • 제30권1호
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    • pp.13-21
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    • 2022
  • 버섯 폐배지는 버섯의 수확 후 발생하는 폐기물계 바이오매스로서 적정처리 방법의 부재와 위탁처리 비용의 상승으로 버섯재배 농가의 처리 부담을 증가시키고 있다. 본 연구에서는 버섯 폐배지의 적정처리를 위한 방법으로 혐기소화를 통한 바이오에너지화 방안을 검토하기 위하여 버섯재배 사용 전 배지(Mushroom medium; MM)와 사용 후 폐배지(Mushroom waste medium; MWM)의 메탄퍼텐셜을 분석하고 혐기소화 과정에서의 유기물의 분해특성을 파악하고자 하였다. 버섯재배 전과 후, MM과 MWM의 이론적 메탄퍼텐셜(Bth)은 0.481, 0.451 Nm3-CH4/kg-VSadded으로 MWM에서 6.2% 낮았으나, 생화학적 메탄퍼셜은 0.155, 0.183 Nm3-CH4/kg-VSadded으로 MWM에서 18% 증가하였다. Modified Gompertz model에 의한 반응속도 분석에서 MM과 MWM의 최대메탄생산량(Rm)은 각각 4.59, 7.21 mL/day이었으며, 지체성장기시간(λ)는 각각 2.78, 1.96 day으로 MWM에서 혐기소화 속도가 증가하였다. Parallel first order kinetics model에 의한 반응속도 분석에서 MM과 비교하여 MWM에서 이분해성 유기물(VSe) 함량이 5.89%, 분해저항성 유기물(VSp) 함량이 2.03% 높았으며, 난분해성 유기물(VSNB) 함량은 7.85%가 낮았다. 따라서, 버섯재배 사용 전 배지보다 폐배지의 혐기소화 특성이 더 우수하였다.