• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.116-120
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• 2013

Characteristics of photocatalytic CO removal process conducting CO conversion by using Pt loaded $TiO_2$ photocatalyst were investigated in a photocatalytic tubular reactor. Effects of Pt loading method onto $TiO_2$, linear velocity of gas stream containing CO gas, CO concentration and moisture content in the gas stream on the conversion of CO to $CO_2$ were examined. It was found that the CO gas could be removed almost 100% by using photocatalytic tubular reactor internally coated with Pt/$TiO_2$ photocatalyst under UV irradiation, when the linear velocity of gas stream was in the range of 0.01~0.25 m/s and CO concentration in the gas stream was ranged from 20 to 100 ppm and the relative humidity of the gas stream was in the range of 20~40%. The conversion of CO gas decreased gradually with increasing linear velocity of gas stream and CO concentration in the gas stream. The moisture in the gas stream could promote the removal of CO gas by means of the generation of OHradicals.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.2
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• pp.163-170
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• 2013

The fine-particles, moisture and variety of hazardous gases are produced during electronic manufacture process. Most of the fine-particles are 0.1~10 ${\mu}m$ in size and the hazardous gases such as HF, $SiH_4$, CO, $NH_3$, etc. seriously affect environment, human's body and manufacturing process. To remove these characterized gases and fine-particles, Water-Cyclone designed and tested for removal efficiency on fine-particles and $NH_3$ under -980Pa negative pressure condition. As a result, under 0.1~1.0 $m^3/min$ flow condition, the efficiency on 5 ${\mu}m$ particles was 80~96%, 10 ${\mu}m$ particles was 86~96%, and 20 ${\mu}m$ particles was 91~99%. Besides, the removal efficiency on soluble gas $NH_3$ was 56.5% at 0.5m3/min and 79.1% at 1.0m3/min under 500 ppm flow concentration and 70.0% at 1.0 $m^3/min$ under 1,000 ppm flow concentration. Therefore, on particles, as the flow rate and particle size increased, the collection efficiency rate was increased. On soluble gas, as the flow rate increased, the removal efficiency was increased under the same concentration.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.3
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• pp.215-220
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• 1999

$SO_2$and CO gas removal characteristics of a wire-to-cylinder type nonthermal discharge plasma reactor in various applied voltage (-dc, ac, fast rising pulse and high frequency pulse) and a crossed dc magnetic field have been investigated. The experiment has been emphasized on the oxidizing characteristics of $SO_2$ and CO gas by $O_3$ and the applying of a crossed magnetic field, which would induce the cyclotronic and drift motions of electrons making the residual time longer in the removal airgap space. And it also would enhance the energy of electrons and the electrophysicochemical actions to remove the pollutant gases effectively. It is found thatthe corona onset voltage and the breakdown voltage were decreased with increasing the crossed magnetic field and decrease initial fed $SO_2$and CO concentration. As a result, a higher ozone generation and $SO_2$ and CO gas removal rate of 20[%] can be obtained with -dc, ac and fast rising pulse corona discharges in the crossed dc current-induced magnetic field. But high frequency pulse didn't show effect in applying of a crossed magnetic field.

• Microbiology and Biotechnology Letters
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• v.24 no.5
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• pp.597-603
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• 1996

This study was carried out to examine degradation characteristics of microalgae Chlorella vulgaris in methane fermentation. We measured COD and VS reduction, gas and methane productivity, VFA (volatile fatty acid), respectively. Then we calculated material balance and hydrolysis rates in soluble and solid material. The substrate concentration was controlled from 14 gCOD$_{cr}$/l to 64 gCOD$_{cr}$/l in batch cultures, and HRT (hydraulic retention time) controlled from 2 days to 30 days in continuous experi- ments. The results were as follows. In batch culture, accumulated gas productivity increased with the increase of the substrate concentration. The SS and VSS was removed all about 30% increase of substrate concentration and the most of the degradable material removed during the first 10 days. The curve of gas and methane production rate straightly increased until substrate concentration is 26 gCOD$_{cr}$/l. In continuous culture experiments, the removal rates at HRT 10days were 20% for total COD and TOC, respectively. At longer HRT, there was no increase in the removal efficiency. At HRT 15 days, the removal rates were 30% for SS and VSS, respectively. Soluble organic materials were rapidly degraded, and so there was no accumulated. Soluble COD concentration was not increase regardless of HRT-increasing. That meaned the hydrolysis was one of the rate-limiting stage of methane fermentation. The first-order rate constants of hydrolysis were 0.23-0.28 day$^{-1}$ for VSS, and 0.07-0.08 day$^{-1}$ for COD.

• Journal of the Korean Applied Science and Technology
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• v.31 no.1
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• pp.159-166
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• 2014

In recent years, researchers have put a considerable effort to decrease the emission of harmful gaseous pollutants to the atmosphere. In order to remove simultaneously $SO_2$ and $NO_X$ from the flue gas of small and medium-sized ship, we designed minimal wet scrubber inside a compact multistage modular system. In this study we proceed experiment of elemental technology at each stage of the scrubber. The each stage is oxidation of NO which is the main component of $NO_X$, and removal of $SO_2$, respectively. $NaClO_2$ was used to oxidize NO gas, and NaOH was used to remove $SO_2$ gas. The maximum NO conversion efficiency and the $SO_2$ removal efficiency are both indicate 100%.

• Journal of Environmental Science International
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• v.22 no.7
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• pp.915-923
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• 2013

Decomposition of non-biodegradable contaminants such as phenol contained in water was investigated using a dielectric barrier discharge (DBD) plasma reactor in the aqueous solutions with continuous oxygen bubbling. Effects of various parameters on the removal of phenol in aqueous solution with high-voltage streamer discharge plasma are studied. In order to choose plasma gas, gas of three types (argon, air, oxygen) were investigated. After the selection of gas, effects of 1st voltage (80 ~ 220 V), oxygen flow rate (2 ~ 7 L/min), pH (3 ~ 11), and initial phenol concentration (12.5 ~ 100.0 mg/L) on phenol degradation and change of $UV_{254}$ absorbance were investigated. Absorbance of $UV_{254}$ can be used as an indirect indicator of phenol degradation and the generation and disappearance of the non-biodegradable organic compounds. Removal of phenol and COD were found to follow pseudo first-order kinetics. The removal rate constants for phenol and COD of phenol were $5.204{\times}10^{-1}min^{-1}$ and $3.26{\times}10^{-2}min^{-1}$, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.4
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• pp.43-53
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• 1997

In this research, the synthetic livestock wastewater was prepared to study the characteristics of organic matter removal, the change of VFA production, and the amount of gas production with respect to the change of ammonium nitrogen concentration in the waste using anaerobic fixed bed process, which is an anaerobic biofilm process. The HRT and operation temperature were 1 day and $35{\pm}1^{\circ}C$, respectively. Also, the characteristics of organic matter removal and the inhibitory effect on microorganism in the anaerobic process were studied on the organic loading and ammonium nitrogen concentration. The results obtained were as follows: For COD loading of $10kg/m^3$-day and five levels of ammonium nitrogen concentration ranging from 1,000 to 5,000 mg/L, organic removal efficiencies were about 81, 74, 67, 58, and 51%, and gas productions were 3,860, 3,520, 3,240, 3,020, and 2,790 ml/l-day, respectively. Average methane contents in the gas produced on COD loading of $10kg/m^3$-day was about 76%. Throughout the whole period of experiment, remaining VFA (as COD base) in the effluent was over 90% of remaining COD. This result indicated the inhibitory effect of high concentration of ammonium nitrogen through the facts that accumulated VFA was almost COD and organic removal efficiency decreased also with the increase of ammonium nitrogen. Especially, that implys which high concentration of ammonium nitrogen not only inhibits methane forming bacteria, but also acid forming bacteria.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.335-338
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• 2003

A finite element-based, integrated process model has been developed and applied to predict the detailed, three-dimensional aspects of the thermo-mechanical behavior occurring in the slab caster considering inclusion removal from molten steel by argon bubble flotation. Gas bubbles are simulated using the dispersion model calculating the volume fraction, and the bubble capture effect is included by a source term in the transport equation for particles. The process model is applied to the investigation of the effect of various process parameters on the inclusion removal in the molten steel.

• Journal of Biosystems Engineering
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• v.28 no.5
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• pp.457-464
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• 2003

The purpose of this study was to develop a pilot scale bio-filter system removing ammonia gas with microorganisms. The system consisted of chaff(filter medium), a blower, a temperature sensor, a moisture sensor, a solenoid valve, and a heating system. Temperature and moisture contents were controlled via a PC to provide the microorganisms with proper environment. The microorganisms used in this study were Bacillius. coagulans NLRI T-6 and Pseudononas. putida NLRI S-21 of bacilli. Performance tests were performed to evaluate gas removal rate during 20 days. The result was shown that the removal rate was high in early days and gradually dropped below 90% without injecting the microbes. However, it was shown that when injecting the microbes, the removal rate was almost 100% and pH value was maintained at between 7 and 9 during the whole twenty-day period.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1777-1779
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• 2001

In this experiment, an attempt to use the sludge pellets as catalyst for NO removal from simulated gas is experimentally investigated by using cylinder type reactor. An experimental investigation has been conducted for NO concentration of 50[ppm], 100[ppm], 200[ppm] balanced with air. a gas flow rate of 5[1/min]. Cylinder type reactor is at upstream of system for corona discharge and packed bed type reactor filled with sludge pellets ate put at downstream of Cylinder type reactor for catalystic effect. And AC voltage to discharge the gases was supplied. In the result, NO removal with magnetic field is higher than that without magnetic field, when packed-bed reactor with sludge pellet is installed at downstream of cylinder reactor NO, $NO_2$ removal rate increased and $O_3$ is not generated.