• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.499-504
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• 2012

Characteristics of overall heat transfer were investigated in a three-phase slurry bubble column with relatively low surface tension media, which has been frequently encountered in the fields of industry. The heat transfer phenomena was examined in the system which was composed of a coaxial vertical heater and a proper of bubble column. The heat transfer coefficient was estimated from the measured mean value of temperature difference between the heater surface and the column proper at the steady state condition. Effects of gas velocity ($U_G$), solid fraction in the slurry phase ($C_S$) and surface tension (${\sigma}_L$) of continuous liquid media on the overall heat transfer coefficient (h) in the bubble column were determined. The mean value of temperature difference was estimated from the data of temperature difference fluctuations with a variation of time. The amplitude and mean value of temperature difference fluctuations with respect to the elasped time appeared to decrease with decreasing the surface tension of liquid phase. The overall heat transfer coefficient between the immersed heated and the bubble column increased with an increase in the gas velocity or solid fraction in the slurry phase, but it decreased with an increase in the surface tension of continuous liquid media. The overall heat coefficient in the slurry bubble column with relatively low surface tension media was well correlated in term of operating variables and dimensionless groups within this experimental conditions.

• Journal of Animal Environmental Science
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• v.6 no.3
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• pp.169-174
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• 2000

TAO system was applied to treatment of piiggery slurry. In the experiments, the volume of influx was differentiated in four types. The features of operation, evaporation rate, and efficiency of successive treatment were drawn. The results are; 1. During the operation, the inside temperature was maintained at over $60^{\circ}C$ with the highest $70.2^{\circ}C$. 2. The evaporation rate of influx volume was 31.4%. And the evaporation volume of per square meter was $108{\;}\ell/\textrm{m}^2$; slightly different from $120{\;}\ell/\textrm{m}^2$ of batch type. 3. The VFAs was decreased by 95% (from $1,538lmg/{\ell}$ in influx to $72.9mg/{\ell}$ in Efflux). Thus, successive operation of TAO system is considered to be possible.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.12
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• pp.1071-1077
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• 2002

Ice adhesion on cooling wall is very important in continuous ice formation. The purpose of the present study is to investigate the possibilities of a three-component aqueous solution as a thermal storage material for the continuous ice formation. By freezing under stirring the solution of 300 mL in a stainless steel vessel which was immersed and cooled in a temperature controlled bath, an ice slurry was formed experimentally with measuring the temperature and stirring load variation. From the experiment, the ice adhesion was suppressed when the supercooling degree decreased and the concentration of aqueous solution increased.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.12
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• pp.1063-1070
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• 2002

To resist ice adhesion on cooling wall is concerned to continuous ice formation in thermal storage system. In this study, ice slurries were formed with two ecological aqueous solution, one is ethanol+silanol and the other is propylene glycol+silanol. By freezing under stirring the solution of $300m\ell$ in a stainless steel vessel which was immersed and cooled in a temperature controlled bath, the shape of ice slurry and the strength of ice adhesion on wall was observed with measuring the temperature and stirring load variation. As the concentration is smaller and the supercooling degree is larger, the ice adhesion is easy to occur. When the stirring load is larger than$ 2.1\times10^{-5}W$, the ice adhesion occurred.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.150-153
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• 2007

Apply electromagnetic stirring system to making rheology slurry of Al7075. This experiment has important element which is the relation between solid fraction percent and melt temperature of Al7075. The rheology slurry of Al7075 eliminated liquid phase to include alloying element of copper and zinc by squeeze casting process. In result the most structure was composed entirely of globular primary $\alpha$. Used this material for this study. This study made a comparison of mechanical property according to heat treatment T6 at each melt temperature ($619^{\circ}C$ and $615^{\circ}C$). The microstructure and component are observed how heat treatment T6 weight with the mechanical property by SEM-EDS.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.4
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• pp.59-66
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• 2008

Anaerobic digestion system is getting more attractive in that it produces biogas in the process of organic waste stabilization. Net energy production is important when biogas production is concerned. In this study, net energy production was evaluated with respect to biogas production and heat losses in a hypothetical digester. Under the condition of digester operation with slurry inflow of 5% of TS, additional fuel is required to maintain digester temperature during the winder season. Substrate therefore, needs to have higher VS contents through co-digestion of silage or food waste that has greater values of methane production rate. Heating input slurry is important in cold season, which covers over 80% of heating requirement. Heat recovery from digestate is valuable to reduce the use of biogas for heating. It seems desirable to minimize slurry inflow when temperature is very low. Psychrophilic digestion may be a feasible option for reducing heating requirement.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.11
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• pp.2159-2168
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• 1992

Coal-water slurry is considered to have the potential for displacing petroleum used in the existing oil-fired industrial and utility boilers. The combustion of coal-water slurry(CWS) is a complex process and little is known about the detailed mechanism. In this paper the combustion behavior of a single suspended droplet of CWS in hot gas stream was investigated. The effect of coal particle size, water content in droplet, initial droplet size, ambient temperature and oxygen fraction in ambient gas were studied. The results are as follows; (1) Increasing the oxygen fraction in ambient gas considerably reduced the char combustion time. (2) The variation of water content and coal particle size in droplet showed little effect on the combustion behavior. (3) In the relatively high temperature ambient gas, the water evaporation time became shorter and the combustion process was stable.

• Journal of Navigation and Port Research
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• v.34 no.1
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• pp.71-75
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• 2010

This study is experimented to observe an influence of experimental conditions on production characteristics of slurry ice by injection operating water to cooling plate. And at this experiment it used ethylene glycol-water solution and the concentration is 10 to 20wt%. The experimental apparatus was constructed of ethylene glycol-water solution and slurry ice storage tank, brine tank, pumps for ethylene glycol-water solution and brine circulating, a mass flow-meter, data logger for fluid temperature measuring and a vertical circular tube with single copper plate as test section. The experiments were carried out under various conditions, with mean velocity of fluid at the entry ranging from 1.0 to 2.0m/s and the cooling temperature of $-17^{\circ}C$ to $-10^{\circ}C$.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.1
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• pp.85-96
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• 1990

Simultaneous removal efficiencies of hydrophilic and hydrophobic gaseous pollutants are experimentally determined, and the macroscopic removal mechanism of pollutants in a dry scrubber is analyzed using the extended model of three phase equilibrium distribution of pollutant at high temperatures that can describe the different morphological conditions of adsorbent and water at varying relative humidities. For the simplicity, the inside of spray dryer is divided into three regions of ; (1) absorption, (2) three-phase equilibrium, and (3) adsorption, and the removal efficiencies of each pollutants at three regions are observed at different experimental conditions to estimate the effects of important parameters of dry scrubber. The laboratory experiments simulate the three regions of spray dryer with the temperature control and thus evaporation rate of water from the slurry particle. $SO_2$ as a hydrophilic gaseous pollutant and vinyl chloride as a hydrophobic toxic gas are selected for the future field application to soid waste incineration, and the two types of slurry are made of the two sorbents ; 10 wt.% $Ca(OH)_2$, and 10 wt.% NaOH. Result of temperature effect shows the height of absorption plus three-phase region is decreased as the operation temperature is increased, which results in the lower removal efficiency of $SO_2$ but higher removal for vinyl chloride in the adsorption region of dry scrubber. The removal efficiency of $SO_2$ is higher by NaOH slurry than by $Ca(OH)_2$ slurry due to the hygroscopic nature of NaOH, while the removal of vinyl chloride is higher in $Ca(OH)_2$ case. From the analysis of redults using three-phase equilibrium distribution model, the effective two-phase partition coefficients can be obtained, and the possible extention in the application of the three-phase equilibrium model in a dry scrubber design has been demonstrated.

• Journal of Powder Materials
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• v.28 no.4
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• pp.331-335
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• 2021

The effects of drying temperature on the microstructure of porous W fabricated by the freeze-casting process of tert-butyl alcohol slurry with WO₃ powder was investigated. Green bodies were hydrogen-reduced at 800℃ for 1 h and sintered at 1000℃ for 6 h. X-ray diffraction analysis revealed that WO₃ powders were completely converted to W without any reaction phases by hydrogen reduction. The sintered body showed pores aligned in the direction of tert-butyl alcohol growth, and the porosity and pore size decreased as the amount of WO₃ increased from 5 to 10vol%. As the drying temperature of the frozen body increased from -25℃ to -10℃, the pore size and thickness of the struts increased. The change in microstructural characteristics based on the amount of powder added and the drying temperature was explained by the growth behavior of the freezing agent and the degree of rearrangement of the solid powder during the solidification of the slurry.