• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.931-936
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• 1992

In operational pont of view, the batch reactor is quite different from the continuous reactor in that it is completely in unsteady states. This makes process variables swing over wide ranges and the process disclose its nonlinerarities. For the most part these nonlinearities are due to reaction heat. Accordingly it is very important to know the informations of reaction heat. This paper presents the method of reaction heat measurement in industrial batch reator which furnishes the limited measurable points. The informations of reaction heat are utilized in modeling of the batch reactor as well as deciding the stability and control variables.

• 한국태양에너지학회 논문집
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• 제22권1호
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• pp.9-21
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• 2002

To develope chemical heat pump using available energy sources, solar heat and other kinds of waste thermal energy, we have studied the heat transfer rate in cylindrical bed reactor packed with calcined Dolomite. Two dimensional (radial and circumferential) Partial differential equations, concerning heat and mass transfer in packed bed of calcined Dolomite, are solved numerically to describe the characteristics of the reaction of calcined Dolomite and heat transfer. The results obtained by numerical analysis about two dimensional profiles of temperature and conversion of reactant in the packed bed reactor and the amount of exothermic heat released from the reactor are follows. It was found that all of calcined Dolomite packed bed kept the reaction temperature of about 750K throughout the entire part of the bed, immediately after the steam was introduced exothermic reaction of hydration was proceeded from the packed bed inpu to output and from wall side to center. The rate of thermochemical reaction depends on the temperature and concentration and it is also governed by the boundary conditions and heat transfer rate in the particle packed bed.

• 한국환경과학회지
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• 제17권6호
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• pp.689-698
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• 2008

Numerical study is conducted to predict effects of radiative heat loss and fuel composition in synthetic gas diffusion flame diluted with $CO_2$. The existing reaction models in synthetic gas flames diluted with $CO_2$ are evaluated. Numerical simulations with and without gas radiation, based on an optical thin model, are also performed to concrete impacts on effects of radiative heat loss in flame characteristics. Importantly contributing reaction steps to heat release rate are compared for synthetic gas flames with and without $CO_2$ dilution. It is also addressed that the composition of synthetic gas mixtures and their radiative heat losses through the addition of $CO_2$ modify the reaction pathways of oxidation diluted with $CO_2$.

• BMB Reports
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• 제29권1호
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• pp.58-62
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• 1996

The structural changes in the electron donor side of the PSII reaction center have been monitored since heat treatment ($45^{\circ}C$ for 5 min) of thylakoids is known to decrease the oxygen evolving activity. In heat-treated spinach chloroplast thylakoids, the inhibitory effect of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) on the electron transport activity of the PSII reaction center from diphenyl carbazide to dichlorophenolindophenol became reduced approximately 3.8 times and [$^{14}C$]-labeled DCMU binding on the D1 polypeptide decreased to 25~30% that of intact thylakoid membranes, implying that the conformational changes of the DCMU binding pocket, residing on the D1 polypeptide, occur by heat treatment. The accessibility of trypsin to the $NH_2$-terminus of the cytochrome b-559 ${\alpha}$-subunit, assayed with Western blot using an antibody generated against the synthetic peptide (Arg-68 to Arg-80) of the COOH-terminal domain, was also increased, indicating that heat-treatment caused changes in the structural environments near the stromal side of the cytochrome b-559 ${\alpha}$-subunit, allowing trypsin more easily to cleave the $NH_2$-terminal domain. Therefore, the structural changes in the electron donor side of the PSII reaction center complexes could be one of the reasons why the oxygen evolving activity of the heat-treated thylakoid membranes decreased.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.133.2-133.2
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• 2010

Fischer-Tropsch synthesis (FTS) was carried out in heat-exchanger typed reactor with cobalt metallic foam catalyst. Considering the heat and mass transfer limitations in the cobalt catalyst, a Co-foam catalyst with an inner metallic foam frame and an outer cobalt catalyst was developed. The Co-foam catalyst was highly selective toward liquid hydrocarbon production and the liquid hydrocarbon productivity at $203^{\circ}C$ reached to $52.5ml/(kg_{cat}{\cdot}h)$, which was higher than that obtained by the Co-pellet. Furthermore, the heat-exchanger typed reactor was developed to efficiently control the highly exothermic reaction heat. The reaction heat generated in the FTS reaction on the cobalt active site was easily transferred to reactor wall by the metallic foam in the catalyst and the transferred reaction heat was directly removed by the hot oil which circulated the wall side of the heat-exchanger typed reactor.

• 대한기계학회논문집B
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• 제33권9호
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• pp.709-717
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• 2009

Heat transfer rate is a very important factor for the performance of a steam reformer because a steam reforming reaction is an endothermic reaction. Coaxial cylindrical reactor is the reactor design which can improve the heat transfer rate. Temperature, fuel conversion and heat flux in the coaxial cylindrical steam reformer are studied in this paper using numerical method under various operating conditions. Langmuir-Hinshelwood model and pseudo-homogeneous model are incorporated for the catalytic surface reaction. Dominant chemical reactions are assumed as a Steam Reforming (SR) reaction, a Water-Gas Shift (WGS) reaction, and a Direct Steam Reforming (DSR) reaction. Although coaxial cylindrical steam reformer uses 33% less amount of catalyst than cylindrical steam reformer, its fuel conversion is increased 10 % more and its temperature is also high as about 30 degree. There is no heat transfer limitation near the inlet area at coaxial-type reactor. However, pressure drop of the coaxial cylindrical reactor is 10 times higher than that of cylindrical reactor. Operating parameters of coaxial cylindrical steam reformer are the wall temperature, the inlet temperature, and the Gas Hourly Space Velocity (GHSV). When the wall temperature is high, the temperature and the fuel conversion are increased due to the high heat transfer rate. The fuel conversion rate is increased with the high inlet temperature. However, temperature drop clearly occurs near the inlet area since an endothermic reaction is active due to the high inlet temperature. When GHSV is increased, the fuel conversion is decreased because of the heat transfer limitation and short residence time.

• 대한기계학회논문집
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• 제19권1호
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• pp.202-211
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• 1995

Heat and hydrogen transfer characteristics have been experimentally investigated for a hydride reaction bed, in which hydride material LaN $i_{4,7}$A $l_{0.3}$ is contained for hydrogen storage. This problem is of particular interest in the design of metal hydride devices such as metal-hydride refrigerators, heat pumps, or metal-hydride storage units. Transient behavior of hydrogen transfer through the hydride materials as well as heat transfer is studied during absorption and desorption processes in detail. The experimental results obtained indicate that the mass flow of the hydrogen is strongly affected by the governing parameters, such as the initial pressure of the reaction bed, absorption or desorption period, and cooling or heating temperature. These mass transfer results are along with the heat transfer rate between hydride materials and heat transfer medium in the reaction bed.d.d.

• 한국산업융합학회 논문집
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• 제8권4호
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• pp.191-196
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• 2005

This study was carried out to investigate the heat storage/release characteristics of the thermochemical reaction of the calcined dolomite with the packed bed shape experimental apparatus for development of chemical heat pump system. In the present study, it was found that MgO of the calcined dolomite was not hydrated during the hydration process under the experimental conditions. Therefore, the MgO of the calcined dolomite can be regard as an inert material. As a result, it was found that all of CaO packed kept the reaction temperature of about $510^{\circ}C$ through the entire part of the bed. The dehydration reaction was incurred first at the wall side area as the supplied heat was transferred through the wall side into the packed bed. As a result of the temperature and concentration spread, the reaction was completed at the wall side progressed into the center.

• 에너지공학
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• 제19권3호
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• pp.195-202
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• 2010

최근 국내 연간 1차 에너지 사용량의 약 30% 이상이 폐열로 손실되어지고 있다. 이러한 현실을 타개하기 위하여, 본 논문에서는 장거리 열수송시 에너지 손실을 최소화할 수 있는 신기술로 화학 열변환을 이용한 장거리 열수송 기술을 채택하여, 화학 열변환에 있어서의 최적조건 도출을 목적으로 하였다. 화학 열변환을 위한 반응에 대해서는 많은 연구와 기술개발이 이루어지고 있으며, 그 중 물질이 안정하고, 값이 저렴하며, 생성물이 가스인 메탄올 분해 합성 반응이 가장 타당한 것으로 판단되었다. 본 연구에서는 장거리 열수송 기술 개발에 필요한 메탄올 분해 합성 반응 촉매를 각각 선정하여, 열수송 시스템 구축을 위한 메탄올 분해 합성 반응의 최적화 조건 도출을 위한 실험 연구를 수행하였다. 메탄올 합성 반응에서는 온도, 압력, $H_2$/CO ratio, 공간 속도, 촉매 형태에 따른 영향을 보았고, 메탄올의 분해 반응에서는 온도, 공간속도, 촉매 형태를 변수로 하여 상압에서 영향을 분석하여 메탄올 분해 합성 반응의 최적화 조건을 제시하였다.

• 설비공학논문집
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• 제16권1호
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• pp.34-41
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• 2004

The chemical heat pump based on the Dehydration/Hydration process with a MgO/$H_2O$ system has been researched. The reactor bed could be expected to store the heat around 200∼37$0^{\circ}C$ by the dehydration reaction and to release the heat around 100∼16$0^{\circ}C$ by the hydration reaction under the heat amplification mode operation. The heat output rate of the heat pump system was evaluated using the experimentally determined parameters. The results show that 6∼50 W/kg of heat output and 0.5∼0.8 of heat recovery ratio are attainable. The heat pump will be applicable for a load leveling in a co-generation system by chemical storage of surplus heat at low heat demand and by supplying heat in the peak load period.