• 청정기술
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• 제15권3호
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• pp.186-193
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• 2009

본 연구에서는 상용운전 중에 있는 반연속식 로터리 킬른형 열분해반응기에 지자체에서 발생되는 필름형 혼합 폐플라스틱을 투입한 후 열분해하여 얻은 저급의 열분해유를 세 형태의 반응온도 프로그램에서 분해반응시키고, 여기에서 얻어지는 생성유의 특성을 논의하였다. 원료인 저급 열분해유의 특성은 원소분석 및 발열량 분석, SIMDIST 분석으로 확인하였고, 각 반응온도 프로그램에 따른 분해반응 결과는 각 성분의 수율분포, 액상 생성물의 누적수율과 생성비 등으로 논의하였다. 연구결과는 한 단계 반응온도 프로그램에 비해 다단계 반응온도 프로그램의 경우가 원하는 생성물인 오일수율이 높았고, 상대적으로 잔류물의 수율은 낮게 나타났다. 연속적인 열분해반응에서 반응온도 프로그램은 생성물의 수율분포 등 생성유 특성에 많은 영향을 주었다.

• 대한금속재료학회지
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• 제50권6호
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• pp.445-448
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• 2012

We studied the effect of temperature and reaction time by investigating the various temperatures and reaction times in the reduction of molybdenum oxide ($MoO_3$) to molybdenum (Mo) powder in hydrogen gas. We also studied the effect of the reaction of reduction according to the various hydrogen gas flow rates. We surveyed the reduction from molybdenum oxide to molybdenum powder in hydrogen gas and checked two temperature ranges, one from $400^{\circ}C$ to $600^{\circ}C$ and the other from $700^{\circ}C$ to $900^{\circ}C$. We found that the reaction ratio of molybdenum oxide increased with an increasing temperature and also increased with an increasing reaction time, but hydrogen gas did not influence the reduction ratio of molybdenum oxide. We examined molybdenum powders fabricated by ball milling for two hours, using with X-ray diffraction (XRD) and a scanning electron microscopy (SEM).

• 공업화학
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• 제18권5호
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• pp.415-423
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• 2007

톱밥 및 왕겨를 주 바이오매스 원으로 선정하여 열분해 특성을 고찰하였다. 열 중량 분석기를 이용하여 승온 속도를 달리하여 질소 분위기의 비등온 조건에서 열분해 분석을 수행하였다. 시료의 열분해 반응은 holocellulose가 주 열분해 대상인 저온 반응 영역과 lignin이 열분해 대상이 되는 고온 반응 영역으로 구분되며 이를 2단계 연속 반응 모델을 사용하여 해석하였다. 각 영역에 따라 1st order reaction model과 3-way transport model을 적용하여 톱밥 및 왕겨의 활성화 에너지를 저온 영역에서 82.5 kJ/mol, 85.1 kJ/mol 그리고 고온 영역에서 19.7 kJ/mol, 22.0 kJ/mol로 결정하였다. 승온 속도를 달리하여 결정된 반응 속도 상수는 Gaur-Reed의 제안 식에 따라 kinetic compensation relation을 통해 해석할 수 있었으며 이를 통해 임의의 승온 속도에서의 열분해 속도 상수를 잘 예측할 수 있었다.

• 한국물환경학회지
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• 제27권6호
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• pp.896-904
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• 2011

The features of the capture reaction of $CO_2$ by ammonia solution have been investigated along with the effect of temperature on the reaction based upon computer program-utilizing calculation and thermodynamic estimation. The stable region of $CO{_3}^{2-}$ was observed to increase with temperature and the change of the stable region of $CO{_3}^{2-}$ with temperature was greater than the temperature variation of the stable region of other carbonate species. The distribution diagram for $NH_4{^+}-NH_3$ system was constructed and the rise of temperature resulted in the decrease of the stability of $NH_4{^+}$ ion, which was thought to be due to the endothermic nature of its acidic dissociation. Considering the introduction of $Ca^{2+}$ ion in the carbon capture reaction by $NH_4{^+}$, the temperature was observed to be important in the determination of the order of reaction between carbonate ion and these cations. The removal process of $CO_2$ gas by ammonia solution was presumed to occur in open system and the temperature variations of the concentration of carbonate system species along with their total concentration were calculated for the proper control and design of the real process.

• Journal of Microbiology and Biotechnology
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• 제17권4호
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• pp.695-700
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• 2007

The cycloinulooligosaccharide fructanotransferase (CFTase) gene (cft) from Paenibacillus macerans (GenBank access code AF222787) was expressed on the cell surface of Saccharomyces cerevisiae by fusing with Aga2p linked to the membrane-anchored protein Aga1p. The surface display of CFTase was confirmed by immunofluorescence microscopy and enzymatic assay. The optimized reaction conditions of surface-displayed CFTase were as follows; pH, 8.0; temperature, $50^{\circ}C$; enzyme amount, 30 milliunit; substrate concentration, 5%; inulin source, Jerusalem artichoke. As a result of the reaction with inulin, cycloinulohexaose was produced as a major product along with cycloinuloheptaose and cycloinulooctaose as minor products.

• 설비공학논문집
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• 제6권2호
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• pp.120-129
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• 1994

A numerical investigation has been carried out for the electrochemical reaction, mass and heat transfer characteristics of the Molten Carbonate Fuel Cell(MCFC) stack. The effects of cooling air channel and water gas shift reaction were taken into account. The current density distribution of electrodes, the molecular fractions of reactant gasses and three dimensional temperature distribution can be calculated and shown by several lines of equivalent values. The results have been compared with the existing ones, and reasonable agreement has been obtained. To examine the influence of changing parameters, such as the composition of reactant gases, the target average current density, the utilization of reactant gases, the cooling air inlet temperature and flow rates, the computer simulation has been done. The analysis method and computer program developed in this study will be greatly helpful to design and verify the optimum operating condition of MCFC stack.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.209-211
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• 2015

Evaporation characteristics of a single droplet of carbon nanofluids were investigated in a rapid compression machine(RCM). n-Heptane and carbon black N990 were used to synthesize the carbon nanofluids. RCM is an experimental set-up to simulate a single compression stroke of reciprocating engine. Temperature and pressure in a reaction chamber were measured during the compression stroke. After the piston reaches top dead center(TDC), temperature and pressure decreased due to the heat loss at wall. In that process, a single droplet of carbon nanofluids underwent unsteady condition. A single droplet was put at the center of reaction chamber. Thermocouple whose tip is $50{\mu}m$ was used not only to measure transient bulk temperature, but also to suspend the droplet. The picture of single droplet was taken using high speed camera with a frame rate of 500 fps. From those pictures, the droplet diameter was measured by visual basic program.

• 대한화학회지
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• 제13권2호
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• pp.187-193
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• 1969

As part of an extensive program on the microbiological oxidation of hydrocarbons, reaction conditions and nutrients consumption of candida lipolytica grown on alkane as carbon source were studied. For optimum growth of yeast, the conditions of pH 5, temperature $30^{\circ}C$, carbon number $C_{16}$& $C_{18}$aeration 25.6 1/l/hr, agitation 3000 r.p.m., hydrocarbon concentration 10% were obtained. Carbon and nitrogen balance related to these conditions were also investigated. In the course of this investigation, some significant effects of pH and carbon number of hydrocarbon variation were observed.

• Journal of Magnetics
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• 제18권1호
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• pp.30-33
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• 2013

The magnetocaloric effect and magnetization behavior have been analyzed in the double-perovskite $La_{0.7}Ba_{0.3}Mn_{1-X}Fe_XO_3$ compound with the sintering temperature at 1273 K. Samples were fabricated by the conventional solid-state reaction method. X-ray diffraction measurement revealed that all the samples had a single phase in orthorhombic. Detailed investigations of the magnetic entropy behavior of the samples were discussed with the variation of $T_C$. The magnetic entropy changes, ${\Delta}S_M$ of approximately 0.36-1.14 J/kg K were obtained in the temperature range of 145-350 K for the $La_{0.7}Ba_{0.3}Mn_{1-X}Fe_XO_3$ compound. The enhancement of the magnetic entropy change is believed to be due to changes in the microstructure, which changes the magnetic part of the entropy of a solid around the magnetic ordering temperature.

• 한국수소및신에너지학회논문집
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• 제23권5호
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• pp.503-512
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• 2012

There is a new power generation system such as direct coal fuel cell (DCFC) with a solid oxide electrolyte operated at relatively high temperature. In the system, it is of great importance to feed coal continuously into anodic electrode surface for its better contact, otherwise it would reduce electrochemical conversion of coal. For that purpose, it is required to improve the electrochemical conversion efficiency by using either rigorous mixing condition such as fluidized bed condition or just by recirculating coal particle itself successively into the reaction zone of the system. In this preliminary study, we followed the second approach to investigate how significantly particle recycle would affect the coal conversion efficiency. As a first phase, coal conversion was analyzed and evaluated from the thermochemical reaction of carbon with air under particle recirculating condition. The coal conversion efficiency was obtained from raw data measured by two different techniques. Effects of temperature and fuel properties on the coal conversion are specifically examined from the thermochemical reaction.