• Resources Recycling
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• v.24 no.5
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• pp.3-14
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• 2015

This study investigated that status of domestic and international furnace desulfurization and desulfurization characteristics of limestone for fluidized bed use depending on the technology for CFBC one of the CCPs. Limestone-based desulfurizing agent is one of the superior elements which are optimal at around $850-950^{\circ}C$ on high temperature desulfurization. And effectiveness of desulfurization process can be determined by the desulfurization experiment method such as diffusion reaction of the diaphragm of the absorber surface, the size of the particles, the pores of the quantity, size and structure. And, desulfurization efficiency depending on geological and crystallographic properties and calcination process of limestone needs additional research in the future.

• Journal of Navigation and Port Research
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• v.34 no.5
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• pp.331-336
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• 2010

The free surface influenced the wake behind a circular cylinder and its effects were investigated experimentally in a circulating water channel with the variation of water depth. Instantaneous velocity fields were measured in this paper. The measured results has been compared with each other to investigate the flow characteristics of the circular cylinder's 2-dimensional section at $Re=1.0{\times}10^3$ using 2-frame grey level cross correlation PIV method. The flow around the circular cylinder with free surface affected the wake structure. Especially, in case of d=1.0D, the boundary layer was measured in the whole area. The separation point and boundary layer of the circular cylinder could be controlled by the water depth.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.605-610
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• 2011

Phase holdup characteristics of relatively large and small bubbles were investigated in a three-phase(gasliquid-solid) fluidized bed of which diameter was 0.105 m(ID) and 2.5 m in height, respectively. Effects of gas(0.01~0.07 m/s) and liquid velocities(0.01~0.07 m/s) and particle size($0.5{\sim}3.0{\times}10^{-3}m$) on the holdups of relatively large and small bubbles were determined. The holdups of two kinds of bubbles in three phase fluidized beds were estimated by means of static pressure drop method with the knowledge of pressure drops corresponding to each kind of bubble, respectively, which were obtained by dynamic gas disengagement method. Dried and filtered air which was regulated by gas regulator, tap water and glass bead of which density was $2500kg/m^3$ were served as a gas, a liquid and a fluidized solid phase, respectively. The two kinds of bubbles in three-phase fluidized beds, relatively large and small bubbles, were effectively detected and distinguished by measuring the pressure drop variation after stopping the gas and liquid flow into the column as a step function: The increase slope of pressure drop with a variation of elapsed time was quite different from each other. It was found that the holdup of relatively large bubbles increased with increasing gas velocity but decreased with liquid velocity. However, the holdup showed a local minimum with a variation of size of fluidized solid particles. The holdup of relatively small bubbles increased with an increase in the gas velocity or solid particle size, while it decreased slightly with an increase in the liquid velocity. The holdups of two kinds of bubbles were well correlated in terms of operating variables within this experimental conditions, respectively.

• Applied Chemistry for Engineering
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• v.21 no.1
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• pp.111-114
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• 2010

In the attrition reactor for the American Society for Testing and Materials (ASTM) D5757-95, the attrition characteristics of catalysts for water gas shift reaction were investigated. The effects of attrition characteristics of low temperature shift catalysts (LTS) and high temperature shift catalysts (HTS) on fluidization phenomena and average particle size were investigated and compared with the attrition characteristics of sand particles. The particle size of catalysts was decreased and particle size distribution in attrition tube was changed due to the effect of gas injection. About 40~50 wt% samples of original catalyst particles were entrained and lost. The amount of fly ash of LTS catalyst was less than that of HTS. Also, the weight of entrained particles which had original particle size of $212{\sim}300{\mu}m$ was lower than any other cases.

• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.638-645
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• 2017

A model for predicting the transport velocity was proposed using the correlation of the particle entrainment rate in the gas fluidized bed. The emptying time method was simulated using correlations of Choi et al. and Li and Kato. In order to exclude the influence of the unit of the gas velocity, the dimensionless velocity obtained by dividing the gas velocity by the terminal velocity was used as the value of the x-axis. The inverse of the particle entrainment rate was used as the value of the y-axis. When increasing the gas velocity, the non-dimensional velocity, at which the decreasing slope of the y-value is 0.398 [$m^2s/kg$] in absolute value, was considered as the transport velocity. The transport velocity predicted by the model was in good agreement even at high temperature and high pressure.

• Journal of the Korean Institute of Gas
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• v.26 no.2
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• pp.1-8
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• 2022

The purpose of this study is to prepare GPTMS((3-Glycidoxypropyl) trimethoxysilane)-SiO₂ nanofluid and analyze the effect of nanofluid injection on carbonate reservoirs. Structural analysis of silica nanoparticles modified by GPTMS was investigated by FTIR(Fourier transform infrared spectroscopy). C-H stretching vibrations at 2,950 cm^-1 indicating the silica surface modification with GPTMS were observed when the silane feed was over 0.5 mmol/g. Also, the coreflooding test by nanofluid injection on the aged limestone and dolomite plug samples was carried out with different particle concentration and flow rate. The incremental oil recovery was up to 18.9%, and contact angle and permeability of carbonate samples were changed by the effect of nanoparticle adsorption on pore which caused wettability alteration and pore size change. Therefore, the prepared nanofluid will be utilized as an injection fluid for enhancing oil recovery and modifying fluid flow properties such as change of rock wettability and permeability in carbonate reservoirs.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.04b
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• pp.52-55
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• 1997

여과가 진행됨에 따라 막의 표면에서 발생하여 여과선속을 저하시키는 케이크층의 형성은 막을 이용한 고-액 분리공정에서 발생하는 가장 큰 문제점의 하나로서 이는 막 분리공정의 경제성을 좌우하는 중요한 인자가 된다. 이러한 문제점을 극복하기 위하여 유체와 막 사이의 상대속도를 증가시켜 여과속도를 향상시키는 십자흐름 여과, 즉 CFF(crossflow filtration)에 대한 연구가 활발히 진행되어 왔다. 그러나 이러한 심자흐름 여과에서도 막과 유체 사이의 상대속도의 증가에 한계가 있고 또한, 막의 기공보다 작은 입자가 막의 기공 내에 침투하여 막을 오염시키는 현상을 예측하기 어렵기 때문에 여과기의 설계에 있어서 많은 문제점이 발생하고 있다. 이에 오염된 막을 재생시키기 위하여 기계적.화학적인 여러 가지 방법들이 개발되고 여과선속을 향상시키는 방법이 꾸준히 연구되어 분리막 기술의 경제성을 향상시켜 왔다. 본 연구에서는 매우 안정된 유동의 하나로서 막 표면의 전단력을 향상시키는 데에 효과가 있다고 알려진 Taylor와류를 응용한 회전막 여과기를 사용하여 여러 가지 크기의 입자에 대한 여과실험을 수행함으로써 이러한 유동이 케이크의 형성에 미치는 영향을 살펴보았다. 또한 여과선속에 영향을 미치는 여러 매개인자를 알아보고 실험결과를 간단한 모델식에 적용해 봄으로써 막의 저항을 예측할 수 있는 모델식으로의 개선 방향을 제시하고자 한다.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.34-38
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• 2005

Characteristics of size, rising velocity and distribution of liquid drops have been investigated in a immiscible liquid-liquid fluidized-bed whose diameter was 0.102 m and 2.5 m in height. Effects of velocities of dispersed (0~0.04 m/s) and continuous (0.02~0.14 m/s) liquid phases and fluidized particle size (1, 2.1, 3 or 6 mm) on the liquid drop properties in the extractor have been determined. The resultant flow behavior of liquid drops became more complicated with increasing the velocity of dispersed or continuous liquid phase. The resultant flow behavior of liquid complicated with increasing the velocity of dispersed or continuous liquid phase. The resultant flow behavior of liquid drops depended strongly upon the drop size and its distribution. The drop size increased with increasing dispersed phase velocity, but decreased with increasing particle size. However, the size of liquid drop exhibited a local maximum with increasing continuous liquid velocity. The size and rising velocity of liquid drops have been well correlated in terms of operating parameters.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.286-293
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• 2005

An interpretation on the solid circulation characteristics in a fluidized-bed process has been carried out as a first step to simulate the dry entrained-bed absorption and bubbling-bed regeneration system for $CO_2$ removal from flue gas. A particle population balance has been developed to determine the solid flow rates and particle size distributions in the process. Effects of principal process parameters have been discussed in a laboratory scale process (absorption column: 25 mm i.d., 6 m in height; regeneration column: 0.1 m i.d., 1.2 m in height). The particle size distributions in absorption and regeneration columns were nearly the same. As gas velocity or static bed height in the absorption column increased, soild circulation rate and feed rate of fresh sorbent increased, however, mean particle diameter decreased in the absorption column. As cut diameter of the cyclone of the absorption column increased, solid circulation rate decreased, whereas feed rate of fresh sorbent and mean particle diameter in the absorption column increased. As attrition coefficient of sorbent particle increased, solid circulation rate and feed rate of fresh sorbent increased but mean particle diameter in the absorption column decreased.

• Journal of Navigation and Port Research
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• v.35 no.5
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• pp.365-370
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• 2011

The ice-thermal energy storage cooling system has been applied to relief a significant portion of the peak demand of electricity during the daytime in summer. Slurry ice type system is one kind of ice-thermal storage cooling system utilizing cheaper off-peak electricity. This study is experimented to observe an influence of experimental conditions on production characteristics of slurry ice by using reversing flow, which is putting reversing material into test section to disturb ice adhesion. At this experiment, poly propylene ball of dimeter 10 mm was used as reversing material, and ethylene glycol-water solution of 20wt% concentration was used as flow material. The experimental apparatus was constructed of the slurry ice making and storage tank(test section), the brine tank, pumps for ethylene glycol-water solution and brine circulating, a mass flow-meter, data logger for fluid temperature measuring. The experiments were carried out under various conditions, with volumetric flow rate, ball filling rate and air filling rate.