• Transactions of the Korean hydrogen and new energy society
• /
• v.15 no.2
• /
• pp.119-128
• /
• 2004

DME(Dimethyl Ether) was directly produced from the synthesis gas using the slurry phase reactor. The catalyst for DME production prepared two types (A type; Cu:Zn:Al=57:33:10, B type; Cu:Zn:Al=40:45:15, molar ratio). It was evaluated for the effect of the reaction medium oil using the small size slurry phase reactor. DME production yield and the methanol selectivity decreased in the order: n-hexadecane oil> mineral oil> therminol oil. The long-term test of DME production was carried out using A and B type catalyst, and n-hexadecane oil and mineral oil, respectively. It was confirmed that the use of A type for the catalyst and n-hexadecane for the reaction medium oil was very useful for the viewpoint of the DME production form the synthesis gas.

• Journal of Korean Society for Atmospheric Environment
• /
• v.12 no.4
• /
• pp.449-457
• /
• 1996

The main purpose of this study was to investigate sulfur dioxide removal performance of flue gas desulfurization system utilizing a Spray Absorption/Drying Reactor. In this system, the size of droplets was considered the most significant factor and tested using a PDA system. Lime slurry flow rate, operating temperature, calcium/sulfur (Ca/S) ratio and applied air pressure were selected as major operation variables and tested/analyzed in terms of system performance. The results are as follows. 1. The $SO_2$ removal efficiencies were 49%, 74%, 85% for Ca$(OH)_2$ slurry flow rate of 10, 20, 30 ml/min, which implies that the increase of slurry flow rate improves removal efficiency. The optimum slurry flow rate in this study was, however, considered 20 ml/min because of constraints of system troubles and absorbent utilization. 2. As Ca/S ratio increased, $SO_2$ removal efficiency was observed to increase. 3. As air pressure, at the atomizing nozzole, increased from 3 to 5 $kg/cm^2, SO_2$ removal efficiency increased from 74% to 80%, because of droplet size reduction due to pressure increase during atomizing process and the increase of surface area, helping mass transfer between gas and liquid phase.

• Korean Chemical Engineering Research
• /
• v.49 no.2
• /
• pp.200-205
• /
• 2011

Axial and radial distributions of bubble holdup were investigated in a slurry bubble column with pilot plant scale(D=1.0 m). Effects of gas velocity, surface tension of continuous liquid medium and solid fraction in the slurry phase on the axial and radial distributions of bubble holdup were examined. The bubble holdup decreased with increasing radial dimensionless distance from the center of the column, while it increased with increasing dimensionless distance in the axial direction from the distributor, in all the cases studied. The radial non-uniformity of bubble holdup increased with increasing gas velocity but decreasing surface tension of liquid medium, while it was not dependent upon the solid fraction in the slurry phase. The axial non-uniformity of bubble holdup increased with increasing gas velocity, but it does not change considerably with variations of liquid surface tension or solid fraction in the slurry phase . The axial and radial distributions of bubble holdup were well correlated in terms of operating variables within this experimental conditions.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.12
• /
• pp.1296-1300
• /
• 2004

SnO$_2$ is one of the most suitable gas sensor materials. The microstructure and surface morphology of films must be controlled because the electrical and optical properties of SnO$_2$ films depend on these characteristics. The effects of chemical mechanical polishing(CMP) on the variation of morphology of SnO$_2$ films prepared by RF sputtering system were investigated. The commercially developed ceria-based oxide slurry, silica-based oxide slurry, and alumina-based tungsten slurry were used as CMP slurry. Non-uniformities of all slurries met stability standards of less than 5 %. Silica slurry had the highest removal rate among three different slurries, sufficient thin film topographies and suitable root mean square(RMS) values.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.25 no.5
• /
• pp.233-239
• /
• 2013

The Thermophysical properties of thermal conductivity, viscosity, and heat capacity for $CO_2$ slurry ($CO_2$ gas and $CO_2$-hydrate mixture) having a high gas phase volume fraction were predicted using the conventional mixture models and the TRAPP model under hydrate formation conditions. Based on the calculated thermophysical properties, the heat transfer coefficient and pressure drop of the $CO_2$ slurry in the tube were predicted. The thermal conductivity of $CO_2$ slurry ranged from 0.02 to 0.2 W/m-K, and the mixture viscosity was larger than that of pure $CO_2$ by 1.9~2.7 times. The heat capacity of $CO_2$ slurry ranged from 63 to 68% of that for pure $CO_2$. The predicted heat transfer coefficient of $CO_2$ slurry was 6 times higher than that of pure $CO_2$. In the separate model, the estimated pressure drop increased with an increase of $CO_2$-hydrate mole fraction, and was 60% of that of pure $CO_2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07a
• /
• pp.389-392
• /
• 2004

As the integrated circuit device shrinks to the smaller dimension, the chemical mechanical polishing (CMP) process was required for the global planarization of inter-metal dielectric(IMD) layer with free-defect. The effect of alternative commerical slurries pads, and post-CMP cleaning alternatives are discuess, with removal rate, scratch dentisty, surface roughness, dishing, erosion and particulate density used as performance metrics. we investigated the performance of $SnO_2$-CMP process using commonly used silica slurry, ceria slurry, tungsten slurry. This study shows removal rate and non-uniformity of $SnO_2$ thin film used to gas sensor by using Ceria, Silica, W-Slurry after CMP process. This study also shows the relation between particle size and CMP with particle size analysis of used slurry.

• Korean Chemical Engineering Research
• /
• v.48 no.3
• /
• pp.359-364
• /
• 2010

Three kinds of functional regions such as continuous slurry(${\varepsilon}_f$), bubble(${\varepsilon}_b$) and wake(${\varepsilon}_w$) regions were identified, and the individual phase holdups of each functional region were determined in a three-phase slurry bubble column of 0.152 m ID. The holdups of bubble and wake were measured by adopting the electrical resistivity probe method. Effects of gas velocity and solid concentration in the slurry phase on the individual holdups of functional regions in the column were discussed. The holdup of continuous slurry phase decreased but that of bubble or wake increased, with an increase in the gas velocity in the column. The increase of solid content in the slurry phase could lead to the increase in the holdup of continuous slurry phase but decrease in the bubble or wake holdup. The portion of wake holdup was in the range of 15~40% of the bubble holdup, which decreased with increasing gas velocity or solid content in the slurry phase. The individual holdups of three functional regions were well correlated with operating variables within this experimental conditions.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.27 no.3
• /
• pp.5-13
• /
• 2019

This study is conducted to investigate the effects of anaerobic treatments of swine manure slurry alone and combination of livestock manure slurry and fruit pomace on biogas production. Anaerobic co-digestion was evaluated in mesophilic tank reactors for 96 day-incubation period. The organic matter loading of anaerobic digestion was 1 kg of volatile solids(VS) per $1m^3{\cdot}day$. The highest methane production was achieved from the combination of swine manure slury and mandarin pomace(70:30) treatment, whereas the lowest daily and cumulative methane yields was observed in swine manure slurry alone treatment. More than two-fold increase in bio-gas and methane production was obtained by combination of livestock manure slurry and mandarin pomace treatment, compared to the swine manure slurry alone treatment. The co-digestion of livestock manure and fruits pomace has advantages to enhance the production of methane gas, compared to digestion of swine manure slurry alone.

• Korean Chemical Engineering Research
• /
• v.47 no.4
• /
• pp.459-464
• /
• 2009

Gas-liquid mass transfer characteristics were investigated in pressurized three-phase slurry bubble columns with variation of column diameter. Effects of gas velocity, operating pressure, liquid viscosity, solid content in the slurry phase and column diameter on the gas-liquid volumetric mass transfer coefficient($k_La$) were determined. The effects of operating variables on the mass transfer coefficient tended to change with variation of column diameter. The mass transfer coefficient increased with increasing gas velocity or operating pressure but decreased with increasing column diameter, liquid viscosity or solid concentration in the slurry phase. The increase trend of $k_La$ value with increasing gas velocity and the decrease trend of $k_La$ value with increasing liquid viscosity, tended to decrease gradually with increasing column diameter. However, the effects of operating pressure and solid concentration in the slurry phase on the $k_La$ value did not change considerably with variation of column diameter. The values of $k_La$ were well correlated with operating variables with in this experimental conditions as $k_La=0.02D^{-0.26}U_G^{0.28}P^{0.43}{\mu}_L^{-0.04}S_c^{-0.35}$.

• Plant Journal
• /
• v.16 no.1
• /
• pp.38-43
• /
• 2020

In this study, Seochon Thermal Power Plant No.1 for anthracite coal was tested to find the proper operation range of limestone slurry pH in the absorber tower which can be operated continuously in compliance with the Air Quality Preservation Act and Seocheon Thermal Power Division's internal regulation, sulfur dioxide average emission regulation. When operating the sulfur dioxide concentration [ppm] in the combustion gas flowing into the desulfurization absorption tower at 370, 400, 460 and 550 ppm while the main operating elements such as the flow rate of the combustion gas were fixed, the proper slurry pH Were 4.4, 4.5, 4.8 and 5.1, respectively. Therefore, it is recommended to operate with the correlation equation, R_pH=0.004×C_in+2.93 derived using sulfur dioxide and the appropriate slurry pH.