• Journal of Pharmaceutical Investigation
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• 제39권1호
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• pp.29-36
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• 2009

Since the quality of final products is significantly affected by the homogeneity of powder mixture, the powder blending process has been regarded as one of the critical pharmaceutical unit processes, especially for solid dosage forms. Accordingly, the monitoring to determine a blending process' end-point based on a faster and more accurate in-line/on-line analysis has attracted enormous attentions recently. Among various analytical tools, NIR (near-infrared) spectroscopy has been extensively studied for PAT (process analytical technology) system due to its many advantages. In this study, NIR spectroscopy was employed with an optical fiber probe for the in-line monitoring of fluid-bed blending process. The position of the probe, the ratio of binary powder mixture, the powder size differential and the back-flush period of the shaking bag were examined as principal process parameters. During the blending process of lactose and mannitol powders, NIR spectra were collected, corrected, calibrated and analyzed using MSC and PLS method, respectively. The probe position was optimized. A reasonable end-point was predicted as 1,500 seconds based on 5% RSD value. As a consequence, it was demonstrated that the blending process using a fluid-bed processor has several advantages over other methods, and the application of NIRS with an optical fiber probe as PAT system for a fluid-bed blending process could be high feasible.

• 한국가스학회지
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• 제22권2호
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• pp.84-89
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• 2018

최근 환경문제로 인해 폭발성 폐기물을 안전하게 소각 처리하는 방법에 대한 연구가 활발히 진행되고 있다. 유동층 소각로를 이용한 처리 공정은 기존 방법보다 연소 가스 배출량이 현저하게 낮으며, 운전의 효율 또한 높다. 본 연구에서는, 폐 추진제 중 가장 많은 양이 폐기되고 있는 Double-based Propellant를 유동층 소각로에서 소각하는 공정을 전산유체역학 프로그램으로 모사하였다. Cylindrical Bed 내부에서 일어나는 7개의 연소 반응이 안전하게 모사되는 것을 확인하였다. 이를 바탕으로 실제 공정 설계를 진행하면, 앞으로 폭발성 폐기물 처리 공정 연구에 새로운 연구 방향을 제시할 것이라 사료된다.

• 한국환경과학회지
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• 제8권1호
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• pp.95-100
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• 1999

Process intensification without any increase in bed requires the exploitation of fluid mechanical phenomena as the basis for elegant solutions to the process engineering problems which result from the need to retain and control the immobilized biomass, and for biomass recovery. The fluidized bed biological reactor provides a solution to these needs. The wastewater treatment characteristics of the fluidized bed was filled with sand media. Indirect aeration were studied experimentally. The researcher was filled with sand particle size(0.60~0.42mm) in three reactors with different section area(A)/height(H), in the state BOD loading 4.5kg-$BOD_5/m^3$ㆍd, and under the fixed state of hydraulic retention time for around 32 minutes.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.274-281
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• 2018

Experimental studies of the hydrodynamic performance of the draft tube conical spout-fluid bed (DCSF) were conducted using pharmaceutical pellets. The experiments were carried out in a DCSF consisted of two sections: (a) a conical section with the cross section of $120mm{\times}250mm$ and the height of 270 mm, (b) a cylindrical section with the diameter of 250 mm and the height of 600 mm. The flow characteristics of solids were investigated with a high speed camera and a pezoresistive absolute pressure transducer simultaneously. These characteristics revealed different flow regimes in the DCSF: packed bed at low gas velocities, fluidized bed in draft tube at higher gas velocities until minimum spouting, and spouted bed. The stable spouting was identified by the presence of two dominant frequencies of the power spectrum density of pressure fluctuation signature: (i) the frequency band 6-9 Hz and (ii) the frequency band 12-15 Hz. The pressure drops across the draft tube as well as the annulus measured in order to better recognize the flow structure in the DCSF. It was observed that the pressure drop across the draft tube, the pressure drop across the annulus, and the minimum spouting velocity increase with the increase in the height of draft tube and distance of the entrainment zone, but with the decrease in the distributor hole pitch. Finally, this study provided novel insight into the hydrodynamic of DCSF, particularly minimum spouting and stable spouting in the DCSF which contains valuable information for process design and scale-up of spouted bed equipment.

• Journal of Pharmaceutical Investigation
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• 제38권6호
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• pp.381-385
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• 2008

Isosorbide dinitrate is an oral assiatant therapy agent of angina pectoris, myocardial infarction and congestive heart failure. The objective of this study was to formulate sustained release containing isosorbide dinitrate and assess their formulation variables. Pellets were prepared by fluid bed process and consist of drug layer and membrane layer. The pellets were coated with ethylcellulose along with $5{\sim}15%$ of plasticizer such as triacetin and diethyl butylrate. In vitro evaluation study was performed by comparative dissolution test between test and reference isosorbide dinitrate preparation. We could prepare sustained pellets of isosorbide dinitrate by fluid bed process which were reduced process time and had high content. The pellet coated with 1% ethylcellulose and triacetin(l5%) had a similar dissolution behavior compare to reference isosorbide dinitrate preparation controlling initial dissolution and those of dissolution at 30 min were 17.25 and 17.09%, respectively. Difference factor and similarity factor were $0{\sim}15$ and $50{\sim}100$ and there was no significant difference in bioequivalence between formulations. It might be concluded that our sustained release pellet of isosorbide dinitrate could be an alternatively delivery system to reference drug preparation.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 15TH KACG TECHNICAL MEETING-PACIFIC RIM 3 SATELLITE SYMPOSIUM SESSION 4, HOTEL HYUNDAI, KYONGJU, SEPTEMBER 20-23, 1998
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• pp.117-121
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• 1998

The Rapid Expansion of supercritical fluid Solutions (RESS) process was applied to particles coating. Experiments were conducted in a fluidized bed with an internal nozzle in the center of the reaction tube. Microcapsules (mean particle size : 49$\mu\textrm{m}$) prepared by spray drying method were used as the core particles. Supercritical CO2 solutions of paraffin were expanded through the nozzle in to the bed that was fluidized by air. Surface morphology prepared particles was observed by SEM. For the inspection of particle size change, particle size distributions were measured before and after coating. The releasing behavior of Mg2+ ions inspected by AA.

• 청정기술
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• 제20권4호
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• pp.359-366
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• 2014

연소전 $CO_2$ 흡수제인 PKM1-SU와 원유의 접촉분해 촉매인 FCC (fluid catalytic cracking)입자의 고온, 고압 조건 마모 실험을 수행하였다. 지름 15.1 cm, 높이 120 cm에 스파저 튜브(sparger tube, 1 mm 오리피스)를 장착한 원통형 기포유동층반응기를 이용하여, 다양한 온도조건($0{\sim}400^{\circ}C$), 압력조건(0~20 bar)에서 입자마모 실험을 수행하였다. BET, 광학현미경, 입도분석기 등을 이용하여 실험 전, 후 입자를 분석 하였다. 또한 기존의 마모도 측정 방법인 ASTM D5757-95방법을 이용하여 층물질의 높이(4.4~10.2 cm) 및 수분 주입이 입자 마모에 미치는 영향에 대하여 확인하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.39.1-39.1
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• 2005

• 한국결정성장학회지
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• 제8권4호
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• pp.673-676
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• 1998

초임계 분출법(RECC)을 미립자 코팅에 이용하였다. 본 실험은 반응관 중심부에 위치한 노즐을 갖고 있는 유동층 내부에서 수행하였다. 핵입자로는 glass beads(500~590$\mu$m, 74$\mu$149$\mu$m)와 brilliant blut로 피복된 glass beads의 두 종류를 사용하였다. paraffin이 용해된 초임계 $CO_2$는 공기에 의해 유동중인 유동층 내부 노즐을 통해 분무시켰다. 핵입자 표면에 코팅물질이 피복됨을 SEM과 FT-IR에 의한 분석을 통하여 확인할 수 있었다. 코팅 전호 brilliant blue의 용출특성을 ABC로 조사한 결과 코팅입자의 용출특성이 향상되었음을 확인하였다.

• Water Engineering Research
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• 제2권3호
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• pp.179-185
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• 2001

The time consuming and expensive nature of experimental research on scouring processes caused by flowing water makes it attractive to develop numerical tools for the predication of the interaction of the fluid flow and the movable bed. In this paper the numerical simulation of scour by a wall jet is presented. The flow is assumed to be two-dimensional, and the alluvium is cohesionless. The solution process, repeated at each time step, involves simulation of a turbulent wall jet flow, solution of the convection-diffusion of sand concentration, and prediction of the bed deformation. For simulation of the jet flow, the governing equations for momentum, mass balance and turbulent parameters are solved by the finite volume method. The SIMPLE scheme with momentum interpolation is used for pressure correction. The convection-diffusion equation is solved for sediment concentration. A boundary condition for concentration at the bed, which takes into account the effect of bed-load, is implemented. The time rate of deposition and scour at the bed is obtained by solving the continuity equation for sediment. The shape and position of the scour hole and deposition of the bed material downstream of the hole appear realistic.