The objective of this study was to know the in vitro effects of supplemental anthelmintic plant extracts on the inhibition of protozoa for reducing methane production in the rumen. A fistulated Holstein cow was used as a donor of rumen fluid. The plant extracts (Lonicera japonica, Zanthoxylum piperitum, Pyrethrum, Torreya nucifera, Ruta graveolens) known to have anthelmintic effect were added to the in vitro fermentation bottles containing the rumen fluid and medium. The rumen protozoal population was depressed by the addition of Pyrethrum, Torreya nucifera and Ruta graveolens. The methane production was also significantly (p<0.05)reduced by addition of Pyrethrum (2.20 ml/g DM), Torreya nucifera (2.36 ml/g DM) and Ruta graveolens (2.20 ml/g DM). The microbial growth in the treatments of Ruta graveolens or anthoxylum piperitum was the greatest after 12 h and 24 h incubations, respectively. The results of this study indicated that anthelmintic plant extracts appeared to reduce methane production by inhibition of ruminal protozoa related with the methanogens living endosymbiotic in protozoal cells.

자동차 연료용 바이오가스의 고순도 메탄 분리정제를 위해 2단 재순환 분리막 공정을 연구하였다. 2단 재순환 분리막공정을 개발하기 위해 폴리설폰(Polysulfone) 중공사 모듈을 채택하여 이산화탄소, 메탄의 순수투과도를 측정하였다. 또한 모델 혼합가스를 대상으로 모듈의 메탄농도와 압력에 대해 투과실험을 수행하여 메탄의 농도와 회수율에 대한 연구를 수행하였다. 그 결과를 토대로 2단 재순환 분리막 파일럿 플랜트를 제작하였으며 현장에서 발생되는 바이오가스를 대상으로 공정변수에 대한 메탄 회수율과 농도에 관한 투과실험을 수행하였다. 제습기와 탈황설비 등의 전처리설비를 거쳐 가스 내의 수분을 500 ppm 이하, 바이오가스내의 황화수소 농도를 20 ppm 이하로 제거하였으며 그 정제된 혼합가스를 대상으로 파일럿 분리막 공정의 막면적비에 따른 운전결과를 알아보기 위하여 1, 2단의 막면적비가 각각 1:1, 1:3, 2:2가 되도록 구성하여 실험을 진행한 결과, 1단의 막면적은 1 m2로 동일하고 2단의 면적비가 1 m2에서 3 m2로 증가하였을 경우 최종 공급유량은 6.6 L/min에서 80.7 L/min로 그리고 메탄 회수율은 메탄순도 95%에서 47.1%에서 92.5%로 증가하였다. 또한, 막 면적비가 1:1로 동일한 경우 전체 면적이 2배로 증가함에 따라서 유량은6.6 L/min에서 100.8 L/min로 회수율은 47.1에서 88.3%를 나타내었다. 1:3 면적비에서 공급유량이 증가하는 경우, 최종 메탄 순도는 감소하고 메탄 회수율은 증가하는 것을 알 수 있었다. 운전압력이 증가할수록 공급유량은 증가하고 회수율은 다소 감소하는 것으로 나타났다. 실험을 통해 유효막면적, 공급압력과 공급유량의 변화가 공정 성능향상에 중요한 영향을 미친다는 것을 확인하였다.

Food waste leachate (FWL) is a serious pollutant waste coming from the food waste recycling facilities in Korea. FWL has a high organic matter content and high COD to nitrogen (COD/N) ratio, which can disturb efficient methane production in the anaerobic digestion of FWL. In the present study a microalga, Clorella vulgaris (C.V), was used as co-substrate for the FWL anaerobic digestion in order to supply nutrients, decrease the COD/N ratio and increase its methane yield. Different co-digestion mixtures (COD/N ratios) were studied by using biochemical methane potential test and modified Gompertz equation for kinetic study. Mixed substrate of FWL and C. vulgaris in the co-digestion clearly showed more the biomethane yield than the sole substrates. The maximum methane production, 827.7 mL-CH4/g-VS added, was obtained for COD/N ratio of 24/1, whereas the highest improvement of methane yield was found for COD/N ratio of 15/1.

극저온 액체 상태의 LNG는 주거용과 산업용으로 공급되기 전에 가스 상태로 변환된다. 이러한 재가스화 과정 중에 LNG는 83.7×104 kJ/kg 정도의 많은 냉열에너지를 제공한다. 이 냉열에너지를 일부 선진국들에서는 질소, 수소, 헬륨과 같은 극저온 유체들의 액화, 제빙 및 냉방시스템에 이용하고 있다. 따라서 우리나라에서도 인천, 평택 및 통영 LNG 인수기지 주변에 LNG의 냉열에너지를 이용한 냉열에너지 회수시스템을 설립할 필요가 있다. 여기서는 저열유속상태에서 상변화를 동반하는 LNG의 유동거동 특성을 파악하기 위해 LNG의 85 %를 차지하는 메탄을 작동유체로 사용하였다. 또한 본 논문은 극저온 열교환기 내부를 흐르는 메탄과 질소, 프로판, R11 및 R134a의 유동경계에 영향을 주는 관 직경, 관의 경사각도 및 포화압력의 효과를 보여준다. 또한 여기서 얻어진 이론적 연구결과와 기존의 실험 데이터와도 비교 되었다. 그리고 메탄의 유동경계에 주는 파이프의 경사각도의 영향은 매우 큼을 알 수 있었다.

페롭스카이트 촉매와 Mo, Bi를 기본으로 하는 복합 산화물 촉매를 이용하여 천연가스의 주성분인 메탄의 부분산화를 통하여 메탄올을 직접 합성하였다. 페롭스카이트(ABO₃) 촉매는 A 및 B site 성분을 변화시키면서 사과산법으로 제조하였으며, Mo, Bi를 기본으로 하는 3성분계 복합 산화물 촉매는 공침법으로 제조하여 반응특성을 살펴보았다. 페롭스카이트 촉매에서 A site에 알칼리 금속인 Sr을, B site에 전이금속인 Cr을 도입한 SrCrO₃ 촉매가 400℃에서 메탄올 선택도 11%로 가장 우수한 결과를 보였다. Mo, Bi를 기본으로 하는 3성분계 복합 산화물 촉매의 경우 모든 촉매에서 메탄 전환율에는 큰 차이를 보이지 않았으며, Cr을 첨가한 Mo-Bi-Cr 복합 산화물 촉매가 400℃에서 메탄올 선택도 15.3% 로 가장 우수한 결과를 나타냈다. 3성분계 복합 산화물 촉매에서 촉매의 활성과 메탄올 선택도는 촉매의 표면적에 정비례하였다.

An in vitro study was conducted to determine the effects of defaunation (removal of protozoa) and forage sources (rice straw, ryegrass and tall fescue) on ruminal fermentation characteristics, methane (CH4) production and degradation by rumen microbes. Sodium lauryl sulfate, as a defaunation reagent, was added into the mixed culture solution to remove ruminal protozoa at a concentration of 0.375 mg/ml. Pure cellulose (0.64 g, Sigma, C8002) and three forage sources were incubated in the bottle of culture solution of mixed rumen microbes (faunation) or defaunation for up to 24 h. The concentration of ammonia-N was high under condition of defaunation compared to that from faunation in all incubations (p<0.001). Total VFA concentration was increased at 3, 6 and 12 h (p<0.05~p<0.01) but was decreased at 24 h incubation (p<0.001) under condition of defaunation. Defaunation decreased acetate (p<0.001) and butyrate (p<0.001) proportions at 6, 12 and 24 h incubation times, but increased propionate (p<0.001) proportion at all incubation times for forages. Effective degradability of dry matter was decreased by defaunation (p<0.001). Defaunation not only decreased total gas (p<0.001) and CO2 (p<0.01~0.001) production at 12 and 24 h incubations, but reduced CH4 production (p<0.001) at all incubation times for all forages. The CH4 production, regardless of defaunation, in order of forage sources were rice straw > tall fescue > ryegrass > cellulose (p<0.001) up to 24 h incubation.

고형페기물 매립지에서 온실가스 배출량 산정은 기후변화에 대응 측면에서 매우 중요한 사항이다. 국내에서 메탄가스 배출량 산정은 주로 IPCC(Intergovernmental Panel on Climate Change)가이드라인에 근거하여 매립지 표면에서 직접적으로 flux chamber를 이용하여 배출량을 측정하거나, 또는 FOD(First Order Decay)방법에 의존하여 왔다. 그러나 FOD방법은 매립특성을 반영한 매립가스발생속도상수(k)를 정확히 산정하는데 어려움이 존재하고, 또한 표면 발산량을 측정하는 방법은 매립지 표면에서 배출량이 다양하고 측정이 한정된 기간에만 국한된다는 문제점을 내재하고 있다. 대안으로 본 연구에서는 plume measurement의 한 방법으로 대기확산모델을 활용한 역모델링기법을 적용하는 것을 검토하였다. 역모델링에 의해서 매립지 메탄가스 배출량을 직접 계산하기 위한 방법론을 정리하고, 실제 대전매립지에서 측정한 메탄농도를 이용하여 역모델링기법을 적용한 매립지 메탄 배출량 산정하는 방법에 대하여 제시하였다. 역모델링 과정을 검증하기 위해서 임의의 배출량으로 모델링을 수행하여 모델 예측농도와 확산변수 를 계산하였으며, 역으로 예측농도와 확산변수 를 이용하여 배출량을 재산정 하였다. 재산정한 배출량이 임의의 배출량과 동일함을 확인함으로써 본 연구에서 제시하고 있는 역모델링 절차가 적절함을 검증하였다. 또한, 본 연구에서는 역모델링 기법을 적용하여 실제 대전매립지를 대상으로 메탄 배출량 산정하였다. 대전매립지를 대상으로 메탄배출량을 산정한 결과 29.65~36.68 g/㎡-day로 산정되었으며, 주요 메탄 배출지점은 매립지 내의 유사한 지점에서 일관되게 나타났다. 본 연구방법은 기존의 방법과 비교하면, 메탄농도의 측정방법이 간단하고 비용이 적게 소요되므로 지속적인 모니터링이 가능한 장점이 있으며, 불균일한 매립지 표면의 배출량을 비교적 간편하게 산출이 가능한 것으로 파악되었다. 한편, 본 연구는 제한된 실험에 의한 결과이므로 향후 실제 매립지 배출량을 직접 측정하거나, 또는 추적자 실험을 통해서 그 방법론을 추가로 검증할 필요가 있는 것으로 판단된다.

The characteristics of odor generation with the production of resources by utilization of methane gases in landfill sites was investigated, and the effect of making resources with landfill gases on the reduction of odor was analyzed in recent years. The greenhouse gas was estimated to reduce from the range of 1,334,940~209,875 tCO₂e with the period of 2008~2017, and the effective odor was diminished with considerable amount. The more effective methods of odor removal with the utilization of waste gases were estimated by studies of similar cases to acquire standard methods of making energy resources by waste gases.

In the present study, potassium and caesium doped Ag/ catalysts were synthesized by simple wet impregnation method and evaluated for selective catalytic reduction (SCR) of NOx using methane. TEM analysis and diffraction patterns demonstrated the finely dispersed Ag particles. BET surface measurements reveal that the prepared materials have moderate to high surface area and the metal amount found from ICP analysis was well matching with the theoretical loadings. The synthesized K-Ag/ and Cs-Ag/ catalysts exhibited a promotional effect on deNOx activity in the presence of and . The long-term isothermal studies at under oxygen rich condition showed the superior catalytic properties of the both alkali promoted samples. The crucial catalytic properties of materials are attributed to NO adsorption properties detected by the NO TPD.

The autothermal reforming reaction of methane was investigated to produce hyd rogen with Ni/CeO2-ZrO2, Ni/Al2O3-MgO and Ni-Ru/Al2O3-MgO catalysts. Honeycomb metalli c monolith was applied in order to obtain high catalytic activity and stability in autothermal r eforming. The catalysts were characterized by XRD, BET and SEM. The influence of various catalysts on hydrogen production was studied for the feed ratio(O2/CH4, H2O/CH4). The O2/CH4 and H2O/CH4 ratio governed the methane conversion and temperature profile of reactor. Th e reactor temperature increased as the reaction shifted from endothermic to exothermic reactio n with increasing O2/CH4 ratio. Among the catalysts used in the experiment, the Ni-Ru/Al2O3-MgO catalyst showed the highest activity. The 60% of CH4 conversion was obtained, and th e reactor temperature was maintained 600℃ at the condition of GHSV=10000h-1 and feed ratio S/C/O=0.5/1/0.5.

The effects of La addition to Ni/CeO2 methane partial oxidation catalysts were investigated. Catalysts were prepared by the impregnation and urea methods. In the preparation of catalysts, La content was changed from 1 wt% to 3wt%. Catalysts that contain 2wt% La showed the highest methane conversion of about 80% and CO selectivity of 84% and H2 selectivity of 70%. This result may be stemmed from that, when La content is 2wt%, a fluorite oxide-type structure is well formed and carbon deposition is also decreased. Among the catalysts, 2.5wt% Ni/Ce(La)Ox showed the highest catalytic activity. From the experiment of changing reaction temperature with 2.5wt% Ni/Ce(La)Ox catalyst, it was found that the optimum reaction temperature is 750℃ and at this temperature methane conversion was about 90%, CO and H2 selectivities were 94 and 80%, respectively.

This study was conducted to test the effect different forages and feeding rates on generation of main greenhouse gases like carbon dioxide and methane in Hanwoo cows. Feeds were given twice per day at 09:00 and 17:00. Greenhouse gases were measured during 12 hours using Mamos-300 from 09:00 to 21:00. The results indicated that the generation of greenhouse gases under different forage categories and feeding rate were significantly different (p<0.05). Whole greenhouse gas tended to decrease in the high concentrate diets. The high timothy supplement ation group showed less amounts of carbon dioxide generation comparing with others group while high silage supplementation resulted more methane generation comparing with other treatments. On the afternoon test, carbon dioxide generation was significantly lower different (p<0.05) in timothy treatment comparing with others.

An in vitro study was conducted to investigate the effect of propionate precursor (malate or fumarate) on fermentation characteristics, production of conjugated linoleic acid (CLA) and methane (CH₄) by rumen microbes when incubated with linoleic acid (C18:2) as a CLA precursor. Total CH₄ production for 12h incubation, however, was greatly reduced (P＜0.0001) by all the supplements compared to that of control, and its production from M-LA or F-LA treatment was smaller than that from LA treatment. Supplementation of M-LA or F-LA also increased concentrations of cis9, trans11-CLA (P＜0.039 - P＜0.001) for all incubation times and trans10,cis 12-CLA at 1h (P＜0.013), 3h(P＜0.036) and 12h (P＜0.025) incubation times compared to LA supplementation.

We have investigated the optical properties of the global haze on Titan from spectra recorded between 7100 and 9200Åwhere CH4 absorption bands of various intensities occur. The Titan spectra were obtained on Feb. 23, 2005 (UT), near the times of the Cassini T3 flyby and Huygens probe, using an optical echelle spectrograph (BOES) on the 1.8-m telescope at Bohyunsan Observatory in Korea. In order to derive the optical properties of the haze as a function of altitude, we developed an inversion radiative-transfer program using an atmospheric model of Titan and laboratory CH4 absorption coefficients available from the literature. The derived extinction coefficients of the haze increase toward the surface, and the coefficients at shorter wavelengths are greater than those at longer wavelengths for the 30 - 120 km altitude range, indicating that the Titanian haze becomes optically thin toward the longer wavelength range. Total optical depths of the haze are estimated to be 1.4 and 1.2 for the 7270 -7360Åand 8940 -9150Å ranges, respectively. Based on the Huygens/DISR data set, Tomasko et al. (2005) reported total optical depths of 2.5 - 3.5 at 8290Å depending on the assumed fractal aggregate particle model. The total optical depths based on our results are smaller than those of Tomasko et al., but they partially overlap with their results if we consider a large uncertainty from possible variations of the CH4 mixing ratio over Titan's disk. We also derived the single scattering albedo of the haze particles as a function of altitude: it is less than 0.5 at altitudes higher than ~150Km the average particle radius is smaller than the wavelengths, whereas near the surface, it becomes comparable or greater.

Purpose of CH4 reference gases Intercomparison is to evaluate measurement ability among different laboratories and to improve problems in analyzing reference gases. As a result, the goal is for being reached a scale within the limits of the possibility in intercomparison. Korea Meteorological Administration (KMA) and Korea Research Institute of Standards and Science (KRISS) carried out CH4 reference gases intercomparison of the Far East Asia managed by Japan and CH4 intercomparison among standard institutions managed by Consultative Committee for Amount of Substance (CCQM) respectively. CH4 reference gas and standard gases is injected to calibrate instrument drift by turns and checked uncertainty of measurement additionally. Expanded uncertainty in intercomparison among meteorological administrations in the Far East Asia showed 1784.3 ppb±0.26%, 1935 ppb±0.29% respectively. Expanded uncertainty in the case of one point calibration and multipoint calibration showed 1903 ppb±0.11%, 1904 ppb±0.32% respectively. One point calibration obtained better result than mult-point calibration because of having an extent of different manufacturing uncertainty in the case of using various standard gases and having an instrument drift caused by long-time analysis. Through these intercomparison experiment, we could know that concentration of CH4 standard gases produced in CMDL was higher about 1.3~1.4% (about 24~26 ppb) than those of KRISS. This is reason caused a difference between manufactured by gravimetric method and manometric method. Therefore, the standard gases is required to intervalidation with standard institutions and GAW observatories. Also, a low level standard gases need to be calibrated by upper level standard gases periodically.

에너지원으로서 수소를 생산하기 위하여 하니컴 구조를 갖는 모노리스에 10 wt% Ni/CeO2-ZrO2 촉매를 담지한 후 메탄의 수증기 개질 실험을 수행하였다. 다른 CeO2/ZrO2 몰비를 갖는 촉매들 중에서, Ni/CeO2-ZrO2(CeO2/ZrO2=4/1)촉매가 700-800℃에서 높은 메탄의 전환율을 보여 주었다. 10wt% Ni/CeO2-ZrO2 촉매가 담지된 금속 모노리스 촉매체는 높은 열전도도와 비표면적들로 인하여 좋은 촉매 특성을 보여줌을 확인할 수 있었다. 또한, 금속모노리스 촉매체는 반응물에서 과다의 수증기에 의한 수소 수율에서 크게 영향을 받지 않음을 알 수 있었다. GHSV=30,000h-1, 반응물 비(H2O/CH4=3.0) 반응온도 800℃에서 금속모노리스 촉매체는 98%이상의 메탄의 전환율을 보여주었다. 생성물 가스에서 CO2/CO의 비는 수증기/메탄의 반응물비가 증가할수록 수성가스화 반응에 의하여 증가됨을 알 수 있었다.

Molecular sieving carbon (MSC) for separating O2-N2 and CO2-CH4 has been prepared through chemical vapor deposition (CVD) of methane and benzene on activated carbon spheres (ACS) derived from polystyrene sulfonate beads. The validity of the material for assessment of molecular sieving behavior for O2-N2 and CO2-CH4 pair of gases was assessed by the kinetic adsorption of the corresponding gases at 25℃. It was observed that methane cracking on ACS lead to deposition of carbon mostly in whole length of pores rather than in pore entrance, resulting in a reduction in adsorption capacity. MSC showing good selectivity for CO2-CH4 and O2-N2 separation was obtained through benzene cracking on ACS with benzene entrantment of 0.40×10-4 g/ml at cracking temperature of 725℃ for a period of 90 minutes resulting in a selectivity of 3.31:1.00 for O2-N2 and 8.00:1.00 for CO2-CH4 pair of gases respectively.

Methane combustion over perovskite catalysts was investigated. For the preparation of catalysts, Co, Mn, Fe, and Ni were used as B-site components of the perovskite catalysts (ABO3) and La was used as A-site component. The effect of calcination temperature on methane combustion and perovskite structure was also investigated. The structure of perovskites, surface area, and adsorbed oxygen species were tested with XRD, BET apparatus, and O2-TPD, respectively. The formation of perovskite structure was affected by the calcination temperature. The catalyst desorbing oxygen at a lower temperature showed better activity for the methane combustion, therefore, the oxygen species desorbing at lower temperatures is responsible for the methane combustion.

The perovskite- type oxide containing transition metals on the B-site show mixed (electronic/ionic) conductivity. These mixed-conductivity oxides are promising materials for oxygen permeating membranes. The main objective of this research work is to synthesize and characterization ceramic powders of the Sr-Co-Fe-O system for methane conversion using membrane reactor. SCFO powders were synthesized from the route was based on the complex method of combination of acid EDTA and citrate and shown be available by control efficient of synthesis to performed , moreover, it presented easy implementation, reproducibility and operation. Powder ceramic was characterized by XRD, microscopic optic, SEM and TG-DTA.