• 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.

• 공업화학
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• 제16권1호
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• pp.131-138
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• 2005

활성탄과 제올라이트 13X에 대한 벤젠의 정적흡착실험으로부터 Freundlich isotherm과 Toth isotherm을 구하였으며 똑같은 흡착제로 충진된 흡착탑을 이용하여 벤젠의 파과곡선을 측정하였다. 파과시간과 벤젠 분압의 관계를 해석하여 Freundlich isotherm의 파라미터를 결정하였다. 파과실험 결과의 해석으로부터 예측되는 벤젠의 흡착량이 정적 실험 결과로부터 예측되는 것과 비교적 잘 일치하였다. 활성탄에 대한 동적 실험 결과에서 좀 더 대칭형태에 가까운 파과곡선이 얻어져서 제올라이트 13X에 비해 더 적은 오차가 나타났다.

• Journal of Microbiology
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• 제43권3호
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• pp.295-300
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• 2005

In the present study, the performances of conventional purification methods, packed bed adsorption (PBA), and expanded bed adsorption (EBA) for the purification of the nucleocapsid protein (NP) of Newcastle disease virus (NDV) from Escherichia coli homogenates were evaluated. The conventional methods for the recovery of NP proteins involved multiple steps, such as centrifugation, precipitation, dialysis, and sucrose gradient ultracentrifugation. For the PBA, clarified feedstock was used for column loading, while in EBA, unclarified feedstock was used. Streamline chelating immobilized with $Ni^{2+}$ ion was used as an affinity ligand for both PBA and EBA. The final protein yield obtained in conventional and PBA methods was $1.26\%$ and $5.56\%$, respectively. It was demonstrated that EBA achieved the highest final protein yield of $9.6\%$ with a purification factor of 7. Additionally, the total processing time of the EBA process has been shortened by 8 times compared to that of the conventional method.

• Advances in environmental research
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• 제12권1호
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• pp.17-40
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• 2023

This article presents studies of the adsorption process in a continuous system of fluoride solutions at a concentration of 30 mg/L using a bone char packed in fixed-bed columns, as well as regeneration studies in the same system using HNO₃, HCl and NaOH at 0.01, 0.1 and 1 M. The Thomas Model, Artificial Neural Networks (ANNs), Numerical Integration and Mass Transfer Zone were used for the modeling of asyemmetrical breakthrough curves obtained from the fluoride adsorption on bone char. The maximum adsorption capacity of the breakthrough curves was estimated, and various design parameters of the columns were obtained for the different operating conditions. Results showed that an improvement in the modeling capabilities of the Thomas model can be obtained using ANNs. Moreover, ANNs are useful for determining reasonable and accurate design parameters of packed-bed adsorption columns. This modeling approach can be useful for the process system engineering of dynamic adsorption systems involved in the field of water treatment and purification. It is important to highlight that the obtained results indicate that, when using HCl or HNO₃ at a concentration of 0.1 M, a large number of adsorption-desorption cycles are obtained and, therefore, the highest values of adsorption capacity, which leads to a reduction in operation costs.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.636-643
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• 2024

The coolability of the debris bed with a simulant of solidified corium is experimentally studied, focusing on the effects of the structure of the axial stratified debris bed on the dryout heat flux (DHF). DHF was obtained for the four structures with different particle sizes for the axial stratified debris bed under top flooding. The experimental results show that the dryout position of the axial stratified debris bed is formed at the stratified interface indicated by the temperature rise, and the DHF of the axial stratified bed is much lower than that of the homogeneous bed packed with the upper small particles. To predict the dryout heat flux of the stratified debris beds, by considering the properties of the mixed area, a one-dimensional dryout heat flux model of the porous medium is derived from a water and vapor momentum equation for porous medium, two-phase permeability modifications, interfacial drag, and the correlation between capillary pressure and liquid saturation and verified with the experimental data. The modified model can give reasonable results under different structures.

• 대한환경공학회지
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• 제27권7호
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• pp.686-689
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• 2005

회분식 및 연속식 충전 복극전해조 사용시 인가전압, 전해시간 및 활성탄 충진고 등이 암모니아성 및 질산성 질소 제거에 미치는 영향을 검토할 목적으로 실험하였다. 회분식 충전복극 전해조에 $4{\times}8$ mesh GAC를 충전한 후 20 V의 전위에서 30분간 전해한 결과 활성탄 충진고가 80 mm인 경우 암모니아성 질소 제거효율은 전해시간 30분에서 99.9%, 질산성 질소 제거효율은 전해시간 60분에서는 97.6%이었다. 그리고 암모니아성 및 질산성 질소를 연속식으로 처리시 활성탄을 280 mm 충전한 충전복극전해조에 총 질소 농도가 30 mg/L가 되도록 조제한 질산암모늄 시료를 6.7 mL/min 속도로 주입하면서 72시간 연속전해 결과 총 질소 제거효율은 약 80% 이상이었다.

• Advances in environmental research
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• 제7권1호
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• pp.29-37
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• 2018

A simple mathematical model for predicting fixed bed adsorption dynamics is described. The model is characterized by a linear adsorption isotherm and a linear driving force expression for mass transfer. Its analytic solution can be approximated with an algebraic equation in closed form which is easily evaluated by spreadsheet computation. To demonstrate one application of the fixed bed model, a previously published adsorption system is used as a case study in this work. The adsorption system examined here describes chromium breakthrough in a fixed bed adsorber packed with imidazole functionalized adsorbent particles and is characterized by a nonlinear adsorption isotherm. However, the equilibrium behavior of the fixed bed adsorber is in essence governed by a linear adsorption isotherm due to the use of a low influent chromium concentration. It is shown that chromium breakthrough is predicted reasonably well by the fixed bed model. The model's parameters can be easily extracted from independent batch experiments. The proposed modeling approach is very simple and rapid, and only Excel is used for computation.

• 한국연소학회지
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• 제13권2호
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• pp.33-41
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• 2008

The high permeability of the gas in the molten iron of the dripping zone of the blast furnace is a major factor in achieving the stable operation of a furnace with high productivity. Basic studies of the liquid flow behavior in a packed bed are necessary to grasp the effect of various operational changes on conditions in the dropping zone. Molten iron and slag together playa critical role in the lower zone, transporting mass and energy, while impairing and redistributing the gas flow. In turn, molten iron and slag undergo physical and chemical changes, and are redistributed radially as they descend to the hearth. In this research, mathematical formulations are derived for the gas and the liquid. The solid phase is fixed with constant porosity. The information for the molten iron and slag includes the hold-up, velocity, pressure, and information related to the areas of interaction between the gas and the liquid, and the solid and the liquid. Predictable results include the velocity, pressure and temperature distribution. Additional parameters include the packed particle size and the air blast rate.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.2053-2056
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• 2000

The experiment on characteristic of $NO_x$ removal for $BaTiO_3$-sludge hybrid packed bed type reactor was conducted. Gas flow rate was 5(${\ell}/min$) and NO concentration was 50, 100 and 150(ppm). The effect on volume percent of $BaTiO_3$ to sludge was investigated, sludge pellets was added to $BaTiO_3$ pellets to increase $NO_x$ removal rate. In the result, when sludge pellets was added, NO removal rate of $BaTiO_3$ - sludge hybrid type was increased from 90.6% to 95%. However $NO_2$ decreased from 88ppm to 10ppm. $O_3$ decreased from 77ppm to 2ppm. $NO_x$ removal rate was increased to 74%.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.165-166
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• 2014

The application of particle reaction model in the packed bed process modeling is discussed for iron ore pellet induration process. Combustion of coke breeze in the pellet is estimated by using shrinking unreacted-core model and grain model in which the progress of chemical reaction is described in different concepts. Under the identical inlet gas and solid conditions, the calculation using shrinking core model showed deviated results in terms of temperature profile and conversion fraction, which may imply the significance of selecting proper particle reaction model in consideration of particle characteristics and process operation conditions.