• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.93-93
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• 2011

Nanostructures consisting of $TiO_2$ particles as a core and carbon as a shell ($TiO_2$@C) were prepared by heat treatment of $TiO_2$ nanoparticles at high temperature in a methane atmosphere. X-ray diffraction and transmission electron microscopy showed that a carbon shell layer was formed well. These structures were used as supports for platinum nanoparticles and the hybrid particles exhibit improved catalytic activity and stability toward ORR compared to Pt on a carbon black (Vulcan XC-72R). It is likely that enhanced catalytic properties of the Pt on $TiO_2$@C could be due to the stability of the core-shell support in comparison with carbon black support.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.598-603
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• 2005

Biogas produced from anaerobic digestion processes has about 60% of methane and about 40% of carbon dioxide. Raw biogas can be used in internal combustion engines either spark ignition or diesel engines. Since the gas has relatively low calorific values, engine power also is lower than rated power values. Modified engines or biogas-specific engines have been utilized in order to increase efficiency. Another option is gas cleansing for increasing its calorific values. A couple of European countries adopted this approach in using biogas for one of transportation fuels, such as $CO_2$ scrubbing with water or special solutions. This study reports the results of water scrubbing for reducing $CO_2$ concentration. In 2.5m-high PVC pipe accepting water, $CO_2$ reduction rates were investigated. When flow rate of $CO_2$ and air mixture was about 5 LPM, $CO_2$ concentration was decreased up to 70%. Higher calorific biogas through water scrubbing is expected to be applied to various commercial engines without costly modification.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.902-905
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• 2009

축사 또는 쓰레기장에서 에서 발생되는 있는 물질인 암모니아, 아민, 메탄, 탄화수소류 등에 대한 처리를 위한 촉매 개발을 수행하였다. 암모니아를 금속산화물형태의 촉매를 사용하여 산화하였을 경우 $N_2$, NO, $NO_2$, $N_2O$가 일정 비율로 생성되게 된다. 이때의 NO, $NO_2$는 악취는 발생하지 않으나 유독성 가스이므로 이에 대한 선택성이 낮은 촉매를 선별하고 온도에 따른 활성능을 시험하여 최적의 촉매조성을 도출하였다. 다양한 산화가를 지닌 망간을 대상으로 각종 조촉매의 혼합에 따른 실험을 수행하여 최적 조성을 도출 하였다. 촉매 선별작업에서는 충전층을 사용하고, 선별된 촉매에 대하여 모노리스에 코팅하여 사용할 수 있는 모노리스형태의 반응기를 장착하여 모노리스 형태 촉매의 반응성 및 피독특성을 실험하였다.

• Journal of Radiation Industry
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• v.8 no.2
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• pp.105-109
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• 2014

This study was conducted to investigate the sensitivity of Arthrobacter sp. PAMC 25486 to various mutagens. ${\gamma}-ray$, UV-ray, Ethyl methane sulfonate (EMS) and hydrogen peroxide ($H_2O_2$) were used as mutagen, and the survival rate of Arthrobacter sp. was measured at various doses of ${\gamma}-ray$ and UV-ray, and concentrations of EMS and $H_2O_2$. Decimal reduction dose ($D_{10}$ value) of Arthrobacter sp. was determined 370 Gy for a gamma irradiation treatment, 0.019 J for a UV ray, 2.5 mM for EMS, and 230 mM for $H_2O_2$. This result will be applied for the development of superior mutant strain of Arctic bacteria producing valuable compounds.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.3
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• pp.15-20
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• 2012

Processing of organic waste is converted to anaerobic digestion for environmental friendly and sustainable energy recovery and reduction of sludge. In this study, ECOPAD (ECOdays' Plug-flow Anaerobic Digster)design for a high solids content and high organic matter content were used to investigate an applicability and efficiency of food waste treatment and poultry wastewater treatment. Case-by-case analysis of treatment efficiency of ECOPAD using food waste of city "P" and city "S". Volatile Solids basis organic removal efficiency of city "P" and city "S" was 84% and 88% respectively. And, the content of methane (P City: 70%, S City: 71%) was measured similarly. In the case of poultry waste bio-gas production was measured to $1.6Nm^3/kg$-VSrem, and methane content was measured to 69%.

• Journal of the Korean Applied Science and Technology
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• v.17 no.1
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• pp.55-61
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• 2000

$Zn_{x}Fe_{3-x}O_{4}(0.00.<X<0.08)$ was synthesized by air oxidation method for the decomposition of carbon dioxide. We investigated the characteristics of catalyst, the form of methane by gas chromatograph after decomposition of carbon dioxide and kinetic parameter. $Zn_{x}Fe_{3-x}O_{4}(0.00.<X<0.08)$ was spinel type structure. The surface areas of catalysts($Zn_{x{Fe_{3-x}O_{4}(0.00.<X<0.08)$) were $15{\sim}27$ $m^{2}/g$. The shape of $Zn_{0.003}Fe_{2.997}O_{4}$ was sphere. The optimum temperature for the decomposition of carbon dioxide into carbon was $350^{\circ}C$. $Zn_{0.003}Fe_{2.997}O_{4}$ showed the 85% decomposition rate of carbon dioxide and the degree of reduction by hydrogen(${\delta}$) of $Zn_{0.003}Fe_{2.997}O_{4}$ was 0.32. At $350^{\circ}C$, the reaction rate constant and activation energy of $Zn_{0.003}Fe_{2.997}O_{3.68}$ for the decomposition of carbon dioxide into carbon were 3.10 $psi^{1-{\alpha}}/min$ and 0.98 kcal/mole respectively. After the carbon dioxide was decomposed, the carbon which was absorbed on the catalyst surface was reacted with hydrogen and it became methane.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.89-92
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• 2007

Partail oxidation(POX) of n-butane was investigated in this research by employing ceria-promoted Ni/calcium hydroxyapatite catalysts ($Ce_xNi_{2.5}Ca_{10}(OH)_2(PO_4)_6$ ; x = $0.1{\sim}0.3$) which had recently been reported to exhibit good catalytic performance in POX of methane and propane. The experiments were carried out with changing ceria content, $O_2/n-C_4H_{10}$ ratio and temperature. As the $O_2/n-C_4H_{10}$ feed ratio increased up to 2.75, n-$C_4H_{10}$ conversion and $H_2$ yield increased and the selectivity of methane and other hydrocarbons decreased. But with $O_2/n-C_4H_{10}$ = 3.0, $n-C_4H_{10}$ conversion and $H_2$ yield decreased. This is considered due to that too much oxygen may inhibit the reduction of Ni or induce the oxidation of Ni, which results in poor catalytic activity. The optimum $O_2/n-C_4H_{10}$ ratio lay between 2.50 and 2.75. $Ce_{0.1}Ni_{2.5}Ca_{10}(OH)_2(PO_4)_6$ showed the highest $n-C_4H_{10}$ conversion and $H-2$ yield on the whole. In durability tests, higher hydrogen yield and better catalyst stability were obtained with the $O_2/n-C_4H_{10}$ ratio of 2.75 than with the ratio of 2.5.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.1
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• pp.50-57
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• 2010

Stepwise production of syn-gas and hydrogen from methane on ferrite based media added with yttria-stabilized zirconia (YSZ) was carried out using a fixed bed infrared reactor. In this study, all M-ferrite (M=Co, Cu, Mn and Ni) media were prepared by co-precipitation method, and there the YSZ was added as a binder to improve thermal stability, reactivity, and resistance against carbon deposition. Most of the ferrite media containing YSZ showed the good redox property for temperature programmed reduction/oxidation (TPR/O) tests. Notably, the Cu-substituted ferrite medium with YSZ showed the great resistance against carbon deposition as well as the good reactivity for the stepwise production of syngas and hydrogen. Furthermore, it also showed the good durability without significant deactivation during five repeated cyclic tests.

• Solar Energy
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• v.18 no.3
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• pp.197-203
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• 1998

A 5 ton/day pilot scale two-phase anaerobic digester was constructed and tasted to treat Korean food wastes in Anyang city. The process was developed based on 3 years of lab-scale experimental results on am optimim treatment method for the recovery of biogas and humus. Problems related to food waste are ever Increasing quantity among municipal solid wastes(MSW) and high moisture and salt contents. Thus our food waste produces large amounts of leachate and bed odor in landfill sites which are being exhausted. The easily degradable presorted food waste was efficiently treated in the two-phase anaerobic digestion process. The waste contained in plastic bags was shredded and then screened for the removal of inert material such as fabrics and plastics, and subsequently put into the two-stage reactors. Heavy and light inerts such as bones, shells, spoons and plastic pieces were again removed by gravity differences. The residual organic component was effectively hydrolyzed and acidified in the first reactor with 5 days space time at pH of about 6.5. The second, methanization reactor part of which is filled with anaerobic fillters, converted the acids into methane with pH between 7.4 to 7.8. The space time for the second reactor was 15 days. The effluent from the second reactor was recycled to the first reactor to provide alkalinities. The process showed stable steady state operation with the maximum organic rate of 7.9 $kgVS/m^3day$ and the volatile solid reduction efficiency of about 70%. The total of 3.6 tons presorted MSW containing 2.9 tons of food organic was treated to produce about $230m^3$ of biogas with 70% of methane and 80kg humus. This process is extended to full scale treating 15 tons of food waste a day in Euiwang city and the produced biogas is utilized for the heating/cooling of adjacent buildings.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.1
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• pp.79-87
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• 2018

Water management impacts both methane ($CH_4$) and nitrous oxide ($N_2O$) emissions from rice paddy fields. Although irrigation is one of the most important methods for reducing $CH_4$ emission in rice production systems it can also $N_2O$ emissions and reduce crop yields. A feasibility study on the system of rice intensification (SRI) methods with respect to irrigation requirements, greenhouse gas (GHG) emissions was conducted for either 2 or 3 years depending on the treatment in Korea. The SRI methods (i.e. SRI and midsummer drainage (MD) with conventional practice (CT)) reduced the irrigation requirement by 49.0 and 22.0 %, respectively. Global warming contribution of GHG to different depending on the type of GHG. Therefore, the emission of $CH_4$ and $N_2O$ shall be converted to Global Warming Potential (GWP). The GHG emission from the conventional practice with midsummer drainage (MD) and the SRI plots, in GWP were reduced by 49.1 and 77.1 %, respectively. Application of SRI water management method could help to improve Korea's water resources and could thus contribute to mitigation of the negative effects of global warming.