• 한국응용과학기술학회지
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• 제17권2호
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• pp.83-88
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• 2000

The VOCs(Volatile Organic Compounds) is one of the major cause for the atmosphere pollution. Breakthrough behavior of benzene and toluene in adsorption bed packed with activated carbon was experimentally studied. Composition and temperature of the gas flowing in the bed was measured and breakthrough curves for each component was obtained. Breakthrough time of benzene was earlier than that of toluene due to relatively weak adsorptivity. The relationship between breakthrough time and flow rate was obtained. The shape of temperature change with time was dependent on the position in the bed. Temperature changed faster and sharper in the inlet than in the outlet. It was noted that breakthrough behavior could be affected by the heat transfer properties.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.115-116
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• 2023

In this study, it was confirmed whether kaolin can play a role as a bed materials and a role in reducing clinkers by using kaolin with a bed materials for the purpose of removing clinkers such as slagging and fouling generated in circulating fluidized bed combustion furnaces using solid fuel.

• 한국식품과학회지
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• 제41권1호
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• pp.27-31
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• 2009

식품의 원료인 참기름을 캡슐화하기 위해 전보(11)에서 최적화한 model system을 기초로 피복물질을 선정하고 이에 3%의 gellan gum을 첨가한 후 유화압력을 20.7 MPa로 하여 유화액을 제조하였다. 이를 top spray dryer와 fluidized bed granulator에 의한 공정으로 캡슐을 제조하여 캡슐화 수율, surface oil, 수분함량, 입자 크기, 캡슐의 저장 안정성 및 제품 응용성을 비교하였다. Fluidized bed granulator에 의한 캡슐은 top spray dryer에 의한 캡슐보다 상대적으로 surface oil 함량이 낮고 수율이 높으며 입자 크기가 컸다. 제조한 캡슐을 $37^{\circ}C$에서 저장하면서 flavor retention을 측정한 결과 참기름 원료 자체를 저장한 경우 향기 성분은 1% 이하의 잔존 함량을 나타내어 대부분의 향기 성분이 소실되었다고 보았으나, top spray dryer와 fluidized bed granulator에 의한 캡슐은 각각 37%, 42%의 향기성분을 보유하여 향기 성분 포집성 및 보존성이 우수하였다. 또한 쇠고기 죽 제품에 응용한 후 관능검사 결과에서도 참기름 캡슐을 사용한 제품들이 모두 참기름 원료 자체를 사용한 제품보다 풍미의 강도 및 기호도면에서 모두 높았고 특히 fluidized bed granulator를 이용하여 제조한 캡슐을 사용한 제품이 가장 우수하게 평가되었다. 따라서 참기름 원료와 같이 향기 성분이 소실 되기 쉬운 소재를 fluidized bed granulator를 이용하여 저온 미세 캡슐화하면 풍미의 안정성 증대에 효과가 있을 것으로 판단된다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2007년도 제34회 KOSCO SYMPOSIUM 논문집
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• pp.63-68
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• 2007

An experimental study was carried out to investigate gasification process of wood sawdust in the 1-dimensional downdraft fixed bed gasifier. The preheated air which was used oxidizer and steam were used as a gasifying agent. The downdraft fixed bed gasifier obtains more amount of hydrogen and methane by increasing residence time of supplied air. The operating parameters, the supplied air temperature and steam were used. The oxidizer temperature was varied from 500K to 620K and vapor was added. The gasification process was monitored by measuring temperature at three position near the biomass using R-type thermocouples and the syngas composition was analyzed by gas chromatograph. We get the sample gas at the end of gasifier and it was eonugh time to finishing the chemical reaction. Finally, the amount of hydrogen and methane were increased widely as increasing the oxidizer temperature and adding steam.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2088-2093
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• 2008

In this study, flow field measurement of the Pebble Bed Reactor(PBR) for the High Temperature Gas-cooled Reactor(HTGR) was performed. Large number of pebbles in the core of PBR provides complicated flow channel. Due to the complicated geometries, numerical analysis has been intensively made rather than experimental observation. However, the justification of computational simulation by the experimental study is crucial to develop solid analysis of design method. In the present study, a wind tunnel installed with pebbles stacked was constructed and equipped with the Particle Image Velocimetry(PIV). We designed the system scaled up to realize the room temperature condition according to the similarity. The PIV observation gave us stagnation points, low speed region so that the suspected high temperature region can be identified. With the further supplementary experimental works, the present system may produce valuable data to justify the Computational Fluid Dynamics(CFD) simulation method.

• 설비공학논문집
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• 제13권3호
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• pp.167-173
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• 2001

This paper represents the numerical analysis for microenvironments various temperature and humidity in bed mattress. He purpose of this study is for healthful bed mattress by controling a bacteria with a prediction of the vapor and temperature distributions in the bed mattress. The numerical model is one dimensional unsteady state and the governing equations were discretized by fully implicit scheme. The numerical results were compared with experimental data, and showed a good agreement with them. Specially, the excess-relative humidity shows a lower distribution near the surface of mattress, meaning that the optimum living condition for bacteria will be caused.

• 분석과학
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• 제13권1호
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• pp.5-11
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• 2000

시운전중인 국내 최대 규모의 유동층 보일러에서 발생한 크링커의 생성원인을 규명하기 위해 현장에서 크링커 및 사용중인 무연탄의 회, 모래, 석회석을 채취하였다. 발전소에서 시행중인 운전조건을 고려하여 이들에 대한 비율별 및 온도 조건 변화에 따른 각 시료의 성분 분석, 표면형상 관찰, 열특성 분석 및 결정구조 분석을 실시하였다. 크링커는 횐 색과 검은 색 및 갈색 부분으로 되어 있었으며 이를 색깔별로 크게 흰 색 및 검은 색으로 구분하여 실험을 하였다. 그 결과 검은 색은 모래, 흰 색은 무연탄 회에 보다 유사한 특성을 지녔고, 온도에 따른 실험 결과, 모래의 소결온도는 $1,200^{\circ}C$ 이상의 고온인 반면에 모래에 석회석을 혼합할 경우, 소결온도가 낮아짐을 알 수 있었다. 따라서 크링커의 생성원인은 유동층 보일러 내에 고온부가 형성되어 모래와 석회석이 용융 또는 소결된 상태에 무연탄회가 부착되어 형성된 것으로 판단되었다.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 1997년도 International Symposium on Fire Science and Technology
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• pp.146-153
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• 1997

An experimental study was performed of natural-convection downward smolder spread across a sawdust bed peripherally enclosed with an insulating container, to examine the effect of the open- ing condition at the top end on downward smolder spread. Experiments were conducted by using relatively coarse sawdust and 25-cm-long cylindrical container The variations of temperature profiles along the bed axis with time were determined far different opening conditions and were com-pared with those in smolder spread from open top to open bottom. It was shown that the smolder zone initiated from open top toward closed bottom penetrates the bed with keeping high peak temperature like the case of open top to open bottom spread, although mean spread rate is smaller. This indicates that the downward smolder zone can be sustained stably if sufficient air or oxygen Is supplied from the back of it by natural convection even if upward draft entering from the bottom of the bed is absent. When the top end was partially closed by mounting a cover after stable smolder spread had begun from open top toward open bottom, the temperature at the peak decreased more than 200 K and the smolder zone became to spread with thickening residue. In this case, the shape of temperature profiles continuously changed or decayed until end-effect at the open bottom end enhanced the reaction. The temperature at the shrunk peak, free from the end-effect, was almost identical with the temperature at the exothermic oxidative-degradation zone in smolder spread from open top to open bottom. from these results, it can be inferred for natural-convection downward smolder spread that the oxidation reaction of the char is very sensitive to the oxygen supply by natural convection in the space above the smolder zone, and that the top end opening condition strongly alters the completeness of reactions, structure, and behavior of the smolder zone.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제20회 KOSCO SYMPOSIUM 논문집
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• pp.67-75
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• 2000

Computational fluid dynamics(CFD) analysis of the thermal flow in a municipal solid waste(MSW) incinerator combustion chamber provides crucial insight on the incinerator performance. However, the combustion of the waste bed is typically treated as an arbitrarily selected profile of combustion gas. A strategy for simultaneous simulation of the waste bed combustion and the thermal flow fields in the furnace chamber was introduced to substitute the simple inlet condition. A waste bed combustion model was constructed to predict the progress of combustion in the bed and corresponding generation of the gas phase species, which assumes the moving bed as a packed bed of homogeneous fuel particles. When coupled with CFD, it provides boundary conditions such as gas temperature and species distribution over the grate, and receives radiative heat flux from CFD. The combined simulation successfully predicted the physical processes of the waste bed combustion and its interaction with the flow fields for various design and operating parameters, which was limited in the previous CFD simulations.

• 식물병연구
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• 제24권4호
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• pp.257-264
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• 2018

딸기 수경재배시스템은 국내에서 매년 증가추세에 있다. 대부분의 딸기농가는 수경재배에서 베드를 멀칭하여 9월 초순 딸기묘를 정식한다. Fusarium oxysporum f. sp. fragariae에 의한 시들음병과 점박이응애 Tetranychus urticae는 정식 후 높은 온도조건에서 발생이 증가하는 경향이 있다. 따라서 베드 녹색 polyethylene(PE)필름 멀칭과 무멀칭처리에서 시들음병과 점박이응애 발생을 비교하기 위해 시험을 실시하였다. 녹색 PE필름 멀칭처리에서 시들음병 발생은 10월 초순부터 시작되었고 무멀칭처리보다 더 증가하였다. 녹색 PE피름 멀칭 처리는 점박이응애의 피해율이 무멀칭처리보다 높았다. 녹색 PE필름 멀칭처리의 상토내 온도는 무멀칭처리보다 증가했지만 대기내 상대습도는 감소하였다. 이런 결과로 딸기 수경재배에서 베드의 무멀칭처리는 시들음병과 점박이응애 발생을 낮추는 효과가 있다고 판단된다.