• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.7
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• pp.32-38
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• 2005

A hybrid discharge type ozonizer, which is superposed silent and surface discharges, has been designed and manufactured to apply for Nitrogen Oxides(NO) gas removal. The ozonizer consists of three electrodes, and is classified three types of ozonizer by changing applied voltage. Investigation was carried out variance with the flow rate of supplied oxygen gas, discharge power and the sorts of superposed discharge type ozonizer. Moreover, NO(1200[ppm])/$N_2$ gas removal investigation was also conducted to apply for environment improvement field. Two kinds of NO gas removal investigations were conducted. It distinguishes the investigations into NO gas reaction method. According to these studies, maximum removal rate of 100[%] in NO gas was obtained, and 8334[ppm] and 3249[mg/h] of maximum ozone concentration and generation were also obtained respectively.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.278-280
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• 2006

A hybrid discharge type ozonizer, which is superposed silent and surface discharges, has been designed and manufactured to apply for Nitrogen Oxides(NO) gas removal. The ozonizer consists of three electrodes, and is classified three types of ozonizer by changing applied voltage. Investigation was carried out variance with the flow rate of supplied oxygen gas, discharge power and the sorts of superposed discharge type ozonizer. Moreover, $NO(1200[ppm])/N_2$ gas removal investigation was also conducted to apply for environment improvement field. Two kinds of NO gas removal investigations were conducted. It distinguishes the investigations into NO gas reaction method. According to these studies, maximum removal rate of 100[%] in NO gas was obtained, and 8334[ppm] and 3249[mg/h] of maximum ozone concentration and generation were also obtained respectively.

• Journal of Biosystems Engineering
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• v.24 no.6
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• pp.465-472
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• 1999

To remove nitrogen oxides(NOx) in exhaust gas of diesel engine, three-way catalytic process with plasma discharger has great possibilities. Characteristics of NOx removal depends on NO conversion to NO$_2$and/or HNO$_3$due to high activation energies for NO oxidation and reduction. NOx removal efficiency by using three-way catalytic with plasma discharger indicated about 50% at 40watt power consumption condition.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.83-90
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• 1999

To remove nitrogen oxides(NOx) in exhaust gas of diesel engine, three-way catalytic process with plasma discharger has great possbilities. Characteristics of NOx removal depends on NO conversion to $NO_2$ and/or $HNO_3$ due to high activation energies for NO oxidationand reduction. NOx removal efficiency by using three-way catalytic with plasma dischager indicated about 50% at 40 watt power consumption condition.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.10
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• pp.861-867
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• 2001

In this paper, in order to investigate the catalytic effect of the sludge exhausted from waterworks on NO$_{x}$ removal, we measure NO removal characteristics with and without sludge pellets in BaTiO$_3$-sludge packed-bed reactor of plate-plate geometry. NO initial concentration is 50 ppm balanced with air and a gas flow rate is 5ι/min. Gas temperature is changed from 25 to 10$0^{\circ}C$ to investigate the role of sludge pellet on removing active oxygen species and NO$_2$. BaTiO$_3$pellets is filled for coronal discharge at upstream of reactor and sludge pellets is filled for catalytic effect at downstream of reactor. The volume percent of sludge pellets to BaTiO$_3$pellets is changed from 0% to 100% and AC voltage is supplied to the reactor for discharging simulated gases. In the results, when sludge pellets is put at the downstream of plasma reactor, NO removal rate is slightly increased. However, NO$_2$and $O_3$ as by-products during NO removal is significantly decreased from 51ppm without sludge pellets to 5 ppm with sludge pellets and from 50 ppm without sludge pellets to 0.004ppm with sludge pellets, respectively. Therefore, NO$_{x}$(NO+NO$_2$) removal rate is increased up to 93%. It is thought that sludge pellet maybe react with active oxygen species and NO$_2$ generated by corona discharge in surface of BaTiO$_3$pellets, the then NO$_2$O$_3$as by-products are considerably decreased. When we increase gas temperature from room temperature to 10$0^{\circ}C$, NO removal rate is decreased, while NO$_2$ concentration is independent on gas temperature. These result suggest that the removal mechanism of active oxygen species and NO$_2$in sludge pellet is not absorption, but chemical reaction. Therefore we expect that sludge pellets exhausted for waterworks could be used as catalyst for NO$_{x}$ removal with high removal rate and low by-product.oduct.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.6
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• pp.755-760
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• 1999

To remove nitrogen oxides(NOx) in exhaust gas of diesel engine three-way catalytic process with plasma discharger has great possibilities. Characteristics of NOx removal depends on NO conver-sion to $NO_2$ and /or $HNO_3$ due to high activation energies for NO oxidation and reduction, NOx removal efficiency by using three-way catalytic with plasma discharger indicated about 50% at 40watt power consumption condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.406-409
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• 1999

Experimental Investigations were carried out to remove NOx, SOx simultaneously from simulated flue gas[NO(0.02%)-SO$_2$(0.08%)-$CO_2$-Air-$N_2$] by using a plasma chemical reaction. Ammonia gas(14.81%) balanced by argon was diluted by all and was Introduced to mall simulated flue gas duct through NH$_3$ Injection system which is in downstream of reactor. The NH$_3$ molecular ratio(MR) was determined based on (NH3) to [NO+S0$_2$]. MR is 1, 1.5, 2.5. The NOx removal rate significantly increased with increasing NaOH bubble quantity. The SO$_2$ removal rate was not significantly effected by applied voltage, however it fairly Increased with increasing NH$_3$ molecule ratio. By-product aerosol particle was observed by XRD(X-ray diffraction) after sampling, The NOx, SOx removal rates, when H2O vapour bubbled by dry all was injected to plasma reactor, were better than those of other cases. When aqueous NaOH solution(20%) bubbled by 2.5( ι /min) of $N_2$ and 0.5 ( ι /min) NH$_3$(MR=1.5) were injected to simulated flue gas, The NOx. SOx removal rate was 95 ~ 100[%]

• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.414-422
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• 2006

Before applying PVA bio-beads to practical biological treatment of nitrate-containing wastewater, their characteristics were examined. PVA bio-beads could steadily produce nitrogen gas from nitrate for 28 batches with 0.04 ml/l/h of the maximum gas production rate; however, the maximum gas production rate dropped remarkably thereafter with apparent deformation of beads. Addition of 2.2% solution containing 1% casamino acid, 1% yeast extract, 0.1% mineral solution, and 0.1% vitamin solution to the culture medium resulted in not only recovery of activity of deactivated beads, but also a higher rate of gas production. Calculation of economic benefit for the use of bio-beads in a long-run operation indicated that reactivation of bio-beads by chemicals had economical advantages over packing new bio-beads in the system. The continuously stirred bioreactor exhibited a satisfactory performance at HRT of 20.0 h. With a 9.5 mg $NO_{3}^{-}N/l/h$ nitrate removal rate, nitrate could completely be removed without nitrite accumulation. The use of PVA bio-beads in nitrate removal appears very promising.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2007-2009
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• 1999

In this paper, discharge domain of wire-cylindrical plasma reactor was separated from a gas flow duct to avoid unstable discharge by aerosol particle deposited on discharge electrode and grounded electrode. The NOx, SOx removal was experimentally investigated by a reaction induced to ammonium nitrate, ammonium sulfate using a low price of aqueous NaOH solution and a small quantity of ammonia. Volume percentage of aqueous NaOH solution used was 20% and $N_2$ flow rate was 2.5[$\ell$/min] for bubbling aqueous NaOH solution. Ammonia gas(14.82%) balanced by argon was diluted by air and was introduced to a main simulated flue gas duct through $NH_3$ injection system which was in downstream of reactor. The $NH_3$ molecular ratio[MR] was determined based on $NH_3$ to [NO+$SO_2$]. MR is 1.5. The NOx removal rates increased in the order of DC, AC and pulse, but SOx removal rates was not significantly effected by source of electricity. The NOx removal rate slightly decreased with increasing initial concentration but SOx removal rate was not significantly effect by initial concentration, and NOx, SOx removal rates decreased with increasing gas flow rate.

• 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.