• Journal of Biosystems Engineering
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• 제31권4호
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• pp.376-384
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• 2006

This study was conducted to perform for comparative analysis of the cleaning efficiency on 3 kinds of cleaning liquid state, 3 steps of cleaning temperature $(45^{\circ}C,\;60^{\circ}C,\;70^{\circ}C,\;)$ and 6 steps of cleaning time (2.5, 5, 7.5, 10, 12.5, 15 minute). 3 kinds of cleaning liquid state are the non fluidized bed, liquid fluidized bed and liquid/solid fluidized bed. UV spectrophotometer was used in estimation of cleaning efficiency, which it is experimental equipment using the absorptiometric analysis method. Cleaning efficiency by cleaning time was increase from 2.5 minutes to 15 minutes, liquid/siolid fluidized bed was indicated the highest cleaning efficiency among the 3 kinds of cleaning liquid state and $70^{\circ}C$ of cleaning temperature at liquid/solid fluidized bed was indicated the highest cleaning efficiency as 98% among the 3 steps of cleaning temperature.

• Korean Chemical Engineering Research
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• 제52권3호
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• pp.371-377
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• 2014

Characteristics of holdup and flow behavior of fluidized solid particles were investigated in a liquid-solid circulating fluidized bed ($0.102m{\times}3.5m$). Effects of liquid velocity ($U_L$), particle size ($d_P$) and solid circulation rate ($G_S$) on the solid holdup, overall particle rising velocity, slip velocity between liquid and particles and hydrodynamic energy dissipation rate in the riser were examined. The particle holdup increased with increasing $d_P$ or $G_S$ but decreased with increasing $U_L$. The overall particle rising velocity increased with increasing $U_L$ or $G_S$ but decreased with increasing $d_P$. The slip velocity increased with increasing $U_L$ or $d_P$ but did not change considerably with $G_S$. The energy dissipation rate, which was found to be closely related to the contacting frequency of micro eddies, increased with increasing $d_P$, $G_S$ or $U_L$. The solid particle holdup was well correlated with operating variables such as $U_L$, $d_P$ and $G_S$.

• Korean Chemical Engineering Research
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• 제61권2호
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• pp.312-321
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• 2023

Fluidized beds have been widely used in industrial applications, which in most of them, the operating fluid is non-Newtonian. In this study, the combination of the lattice Boltzmann method (LBM) and the smoothed profile method has been developed for non-Newtonian power-law fluids. The validation of the obtained model were investigated by experimental correlations. This model has been used for numerical studying of changing the operating fluid and geometrical parameters on the expansion behavior in liquid-solid beds with both Newtonian and non-Newtonian fluids. Investigations were performed for seven different geometries, one Newtonian, and two non-Newtonian fluids. The power-law index was in the range of 0.8 to 1, and the results for the Newtonian fluidized beds show more porosity than the non-Newtonian ones. Furthermore, increasing the power-law index resulted in enhancing the bed porosity. On the other hand, bed porosity was decreased by increasing the initial bed height and the density of the solid particles. Finally, the porosity ratio in the bed was decreased by increasing the solid particle diameter.

• Korean Chemical Engineering Research
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• 제53권4호
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• pp.440-444
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• 2015

Effects of operating variables on the solid circulation rate were investigated in a three-phase circulating fluidized bed, of which inside diameter was 0.102m and height was 3.5m, respectively. Gas velocity, primary and secondary liquid velocities, particle size and height of solid particles piled up in the solid recycle device were chosen as operating variables. The solid circulation rate increased with increasing primary and secondary liquid velocities and height of solid particles piled up in the solid recycle device, but decreased with increasing particle size. The value of solid circulation rate decreased only slightly with increasing gas velocity in the riser. The values of solid circulation rate were well correlated in terms of dimensionless groups within the experimental conditions.

• Korean Chemical Engineering Research
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• 제56권2호
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• pp.186-190
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• 2018

For the first time, the characteristics of solid circulation rate ($G_S$) were investigated in a three-phase (gas-liquid-solid) viscous circulating fluidized bed (TPCFB). The solid circulation rate was controlled separately by adjusting the experimental apparatus as well as operating variables. Effects of primary and secondary liquid velocities ($U_{L1}$ and $U_{L2}$), gas velocity ($U_G$), particle size ($d_p$), height of particles piled up in the solid recycle device (h), and viscosity of continuous liquid media (${\mu}_L$) on the value of $G_S$ were determined. The experimental results showed that the value of $G_S$ increased with increases in the values of $U_{L1}$, $U_{L2}$, h and ${\mu}_L$, while it decreased with increasing $U_G$ and $d_p$ in TPCFBs with viscous liquid media. The values of $G_S$ were well correlated in terms of dimensionless groups within this experimental conditions.

• Korean Chemical Engineering Research
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• 제49권6호
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• pp.790-797
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• 2011

Hydrodynamic similarity was analyzed by employing scaling factor in three phase fluidized beds. The scaling factor was defined based on the holdups of gas, liquid and solid particles and effectivity volumetric flux of fluids between the two kinds of fluidized beds with different column diameter. The column diameter of one was 0.102 m and that of the other was 0.152 m. Filtered compressed air, tap water and glass bead of which density was 2,500 kg/$m^3$ were used as gas, liquid and solid phases, respectively. The individual phase holdups in three phase fluidized beds were determined by means of static pressure drop method. Effects of gas and liquid velocities and particle size on the scaling factors based on the holdups of each phase and effective volumetric flux of fluids were examined. The deviation of gas holdup between the two kinds of three phase fluidized beds decreased with increasing gas or liquid velocity but increased with increasing fluidized particle size. The deviation of liquid holdup between the two fluidized beds decreased with increasing gas or liquid velocity or size of fluidized solid particles. The deviation of solid holdup between the two fluidized beds increased with increasing gas velocity or particle size, however, decreased with increasing liquid velocity. The deviation of effective volumetric flux of fluids between the two fluidized beds decreased with increasing gas velocity or particle size, but increased with increasing liquid velocity. The scaling factor, which was defined in this study, could be effectively used to analyze the hydrodynamic similarity in three phase fluidized processes.

• Applied Chemistry for Engineering
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• 제16권1호
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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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• 제54권5호
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• pp.706-711
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• 2016

Characteristics of solid circulation rate in the liquid-solid circulating fluidized beds with viscous liquid medium were investigated. Effects of primary and secondary liquid velocities, particle size, liquid viscosity and height of solid particles piled up in the solid recycle device on the solid circulation rate were considered. The solid circulation rate increased with increasing primary and secondary liquid velocities, liquid viscosity and height of solid particles in the downcommer, but it decreased with increasing particle size. The particle rising velocity in the riser decreased with increasing the ratio of $U_{L1}/U_{L2}$ and particle size. The slip velocity of liquid and particle, $U_L/U_S$, decreased with increasing liquid viscosity but it increased with increasing particle size. The values of solid circulation rate were well correlated in terms of operating variables and dimensionless groups.

• Applied Chemistry for Engineering
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• 제16권4호
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• pp.485-490
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• 2005

Effects of gas injectino on the copper recovery form industrial waste water in a fluidized-bed electrolytic reactor were investigated. Effects of gas injection on the individual phase holdup and efficiency of copper recovery for given operating variables such as liquid and gas velocity (0.1~0.4 cm/s), current density ($2.0{\sim}3.5A/dm^2$) and amount of fluidized solid particles (1.0~4.0 wt%) were examined. The solid particle, whose diameter and swelling density were 0.5 mm and $1100kg/m^3$, respectively, was made of polystylene and divinyl benzene. It was found that the holdup of gas and solid phases increased, but that of the liquid phase decreased with increasing velocity of gas injected into the reactor. With increasing gas and/or liquid velocity and increasing amount of fluidized particles is not needed, the rate of copper recovery increased to a maximum value of and subsequently decreased. The recovery rate of copper increased almost linearly with increasing current density in accordance with Faraday's law.

• Korean Chemical Engineering Research
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• 제58권4호
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• pp.651-657
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• 2020

Fluidization processes in which solid particles vividly move like gas or liquid have been widely used in various industrial sectors, such as thermochemical energy conversion and polymerization processes for general purpose polymer resins. One of the general purpose polymer resins, LLDPE(Linear low-density polyethylene) resins have been produced in bubbling fluidized bed processes in the world. In a bubbling fluidization polymerization reactors, LLDPE particles with relatively larger particle size and low density are fluidized by hydrogen gas for polymerization reaction. Though LLDPE polymerization reactors are one of bubbling fluidization processes, slugs that have negative impact for reaction exist or occur in these processes. Therefore, the fluidization state of LLDPE particles was investigated in a simulation model similar to a pilot-scale polymerization reactor (0.38 m l.D., 4.4 m High). In particular, the effect of gas velocity (0.45-1.2 m/s), solid density (900-199 kg/㎥), solid sphericity (0.5-1.0), and average particle size (120-1230 ㎛), on bed height and fluidization state were measured by using a CPFD(Computational particle-fluid dynamics) method. With CPFD analysis, the occurrence of a flat slug was visualized. Also, the change in particle properties, such as particle density, sphericity, and size, could reduce the occurrence of slug and bed expansion.