• Journal of the Korean Society of Combustion
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• v.3 no.1
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• pp.11-19
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• 1998

The influence of oxidant addition on soot formation is investigated experimentally with ethylene, propane and mixture fuel co-flow diffusion flames. Oxidant addition into fuel shows the increase of integrated soot volume fractions for ethylene, ethylene/ethane and ethylene/methane mixture flames. However, the increase of integrated soot volume fraction with oxidant addition was not significant for propane and ethylene/propane mixture flames. This discrepancy is explained with $C_2\;and\;C_3$ chemistry at the early stage of soot formation process. The oxidant addition increases the concentration of $C_3H_3$ in the soot formation region, and therefore, enhances soot formation process. A new soot formation rate model that includes both dilution effect and chemical effect of oxygen is suggested to interpret the increase of integrated soot volume fractions with oxidant addition into ethylene. Also, the role of adiabatic flame temperature for the chemical effect of oxygen addition into fuel was reviewed. The influence of oxidant or diluent addition into fuel on soot formation process are the fuel dilution effect, the adiabatic flame temperature altering effect and/or the chemical effect of oxygen. Their relative importance could change with fuel structure and adiabatic flame temperature.

• 한국연소학회:학술대회논문집
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• 2000.12a
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• pp.33-46
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• 2000

In the present study, a systematic chemical kinetic calculations were made to investigate the augmentation of NO-$NO_2$ conversion due to the addition of various hydrocarbons (methane, ethylene, ethane, propene, propane) in the nonthermal plasma treatment. It is included in the present conclusion that the reaction between hydrocarbon and oxygen radicals induced by electron collision, is believed to be a primarily process for triggering the overall NO oxidation and the eventual NOx reduction. Upon the completion of the initiating step, various radicals (OH, $NO_2$ etc.) successively produced by hydrocarbon decomposition form the primary path of NO-$NO_2$ conversion. When the initiating step is not activated, hydrocarbon consumption rate appeared to be very low, thereby the targeted level of NO conversion can only be achieved by the addition of more input energy. Present study showed ethylene and propene to have higher affinity with 0 radical under all conditions, thereby both of these hydrocarbons show very fast and efficient NO-$NO_2$ oxidation. It was also shown that propene is superior to ethylene in the aspect of NOx removal.

• 한국연소학회:학술대회논문집
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• 2000.05a
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• pp.178-188
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• 2000

In the present study, a systematic chemical kinetic calculations were made to investigate the augmentation of $NO-NO_{2}$ conversion due to the addition of various hydrocarbons (methane, ethylene, ethane, propene, propane) in the nonthermal plasma treatment. It is included in the present conclusion that the reaction between hydrocarbon and oxygen radicals induced by electron collision, is believed to be a primarily process for triggering the overall NO oxidation and the eventual NOx reduction. Upon the completion of the initiating step, various radicals (OH, $HO_{2}$ etc.) successively produced by hydrocarbon decomposition form the primary path of $NO-NO_{2}$ conversion. When the initiating step is not activated, hydrocarbon consumption rate appeared to be very low, thereby the targeted level of NO conversion can only be achieved by the addition of more input energy. Present study showed ethylene and propene to have higher affinity with 0 radical under all conditions, thereby both of these hydrocarbons show very fast and efficient $NO-NO_{2}$ oxidation. It was also shown that propene is superior to ethylene in the aspect of NOx removal.

• Journal of computational fluids engineering
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• v.21 no.1
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• pp.43-49
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• 2016

Thermal cracking is commonly modeled as plug flow reaction, neglecting the lateral gradients present. In this paper, 2-dimensional computational fluid dynamics including turbulence model and molecular reaction scheme are carried out. This simulation is solved by means of coupled implicit scheme for stable convergence of solution. The reactor is modeled as an isothermal tube, whose length is 1.2 m and radius is 0.01 m, respectively. At first, The radial profile of velocity and temperature at each point are predicted in its condition. Then the bulk temperature and conversion curve along the axial direction are compared with other published data to identify the reason why discussed variations of properties are important to product yield. Finally, defining a new non-dimensional number, Effect of interaction with turbulence, heat transfer and chemical reaction are discussed for design of thermal cracking furnace.

• 한국석유지질학회:학술대회논문집
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• autumn
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• pp.40-49
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• 1999

The chemical compositions of natural gases and isotopic compositions of hydrocarbon gases were analyzed to characterize the properties of the gases which were found in the exploratory wells from offshore Korea, as well as those dissolved in the ground water onshore in the Pohang area. Natural gases from the offshore area mainly consisted of hydrocarbon gases $(97.98{\~}100{\%})$. The gases were composed of methane $(90{\~}96{\%})$ and minor amounts of heavier components up to $C_{6+}$ Hydrocarbon gases extracted from the groundwater in the Pohang area consisted of methane $(27{\~}376420 ppm)$ and ethane $(19{\~}127 ppm)$. The total amount of hydrocarbon gases was related to the lithology and geological factors surrounding the reservoir. The quantity of the hydrocarbon gases tended to Increase in the Tertiary reservoirs and in the reservoirs where the Tertiary formations were thickly distributed. According to the methane contents, composition of hydrocarbon gases, and stable isotope data, gases from offshore wells are identified as thermogenic in origin, generated during catagenesis stage of the oil window. On the otherhand, based on the methane content $(>99.9\%)$ and isotopic composition $(\delta^{13} C^;\; -73.1{\sim}\;-43.22{\%}_{\circ})$, it is interpretated that the gases from the Pohang area are predominantly composed of biogenic origins, which were generated by the methanogenic bacterial processes under low temperatures and anoxic conditions.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.569-572
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• 2007

천연가스의 주요 구성성분은 메탄, 에탄, 프로판으로 99%이상 차지하고 있으며 천연가스 하이드레이트(NGH)는 압축천연가스(CNG)에 비해 체적당 질량이 크고 액화천연가스(LNG) 보다 상대적으로 유리한 온도 및 압력조건으로 인해 천연가스의 경제적인 저장 및 수송 수단으로 주목 받고 있다. $CH_4$ - $C_2H_6$, $CH_4$ - $C_3H_8$ 혼합가스 하이드레이트의 제조시 반응시간에 따른 하이드레이트의 거동을 관찰하였으며 생성조건의 변화에 따른 하이드레이트의 생성속도를 비교하였다. 하이드레이트의 생성이 진행될 때 기상에서의 $C_2H_6$, $C_3H_8$의 몰 비는 감소함을 보여주었고 이러한 변화는 $CH_4$ - $C_3H_8$가 $CH_4$ - $C_2H_6$보다 더욱 빠르게 진행되었다. 또한 생성된 하이드레이트의 해리과정이 진행될 때 역시 서로 다른 해리속도에 의해 조성의 변화를 관찰 할 수 있었다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.136-139
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• 2003

The combined effect of bioaugmentation of dechlorinating bacterial cultures and addition of iron powder (Fe$^{0}$ ) on reductive dechlorination of tetrachloroethylene (PCE) and other chlorinated ethylenes in a artificially contaminated soil slurry (60$\mu$mo1es PCE/kg soil) were tested. Two different anaerobic bacterial cultures, a pure bacterial culture of Desulfitobacterium sp. strain Y-51 capable of dechlorinating PCE to cis-1, 2-dechloroethylene (cis-DCE) and the other enrichment culture PE-1 capable of dechlorinating PCE completely to ethylene, were used for the bioaugmentation test. Both treatments introduced with the strain Y-51 and PE-1 culture (3mg dry cell weight/kg soil) showed conversion of PCE to cis-DCE within 40 days. The treatments added with Fe$^{0}$ (0.1 -1.0 %(w/w)) alone to the soil slurry resulted in extended PCE dechlorination to ethylene and ethane and the, dechlorination rate depended on the amount of Fe$^{0}$ added. The combined use of the bacterial cultures with Fe$^{0}$ (0.1-1.0%) showed the higher PCE dechlorination rate than the separated application and the pattern of PCE dechlorination and end-product formation was different from those of the separated application. These results suggested that the combined application of Fe$^{0}$ and the bactrial culture, specially the complete dechlorinating enrichment culture such as PE-1 culture, would be practically effective for remediation of PCE contaminated soil.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.5
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• pp.653-660
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• 1999

This work describes analysis on the effect of inlet air cooling by the cold energy of liquefied natural gas(LNG) on the performance of gas turbines. Gas turbine off-design analysis program to simulate the influence of compressor inlet temperature variation is prepared and an inlet air cooler is modeled. It is shown that the degree of power augmentation is much affected by the humidity of inlet air. If the humidity is low enough, that is the water content of the air does not condense, the temperature drop amounts to $18^{\circ}C$, which corresponds to more than 12% power increase, in case of a $1350^{\circ}C$ class gas turbine with methane as the fuel. Even with 60% humidity, about 8% power increase is possible. It is found that even though the fuel contains as much as 20% ethane in addition to methane, the power improvement does not change considerably. It is observed that if the humidity is not too high, the current system is feasible oven with conceivable air pressure loss at the inlet air cooler.

• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.488-496
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• 2002

SPME techniques have proven to be very useful tools in the analysis of wide VOCs in the air. In this study, we estimated VOCs in ambient and workplace air using a Tedlar ba /SPME/GC/MS system. The calibration curve was set to be linear over the range of 1-30 ppbv. The detection limits ranged from 10 pptv to 0.93 ppbv for all VOCs. Reproducibility of TO-14 target gas mixtures by SPME/GC/MS averaged at 8.8 R.S.D (%). Air toxic VOCs (hazardous air pollutants, HAPs) containing a total of forty halohydrocarbons, aromatics, and haloaro-matic carbons could be analyzed with significant accuracy, detection limit and linearity at low ppbv level. Only reactive VOCs with low molecular weight, such as chloromethane, vinylchloride, ethylchloride and 1,2-dichloro-ethane, yielded relatively poor results using this technique. In ambient air samples, ten VOCs were identified and quantified after external calibration. VOC concentration in ambient and workplace air ranged from 0.04 to 1.85 ppbv. The overall process was successfully applied to identify and quantify VOCs in ambient/workplace air.

• Biomolecules & Therapeutics
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• v.10 no.3
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• pp.137-141
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• 2002

Taurine, amino acid, chemically known as 2-amino ethane sulphonic acid was discovered more than two hundred years ago from ox bile. it is widely distributed in both mammals and nonmammals. It is found in considerably high amount in hUl11an: a normal adult of 70 kgs contains about 70 grams of taurine. Taurine with this much concentration, is involved in almost all life processes. Its deficiency causes several abnormalities in major organs like brain, eye and heart. Taurine-bone interaction is latest addition to its long list of actions. In bone cells, taurine is also found in high concentration. Taurine is found to help in enhancing the bone tissue formation which is evidenced by increased matrix formation and collagen synthesis. Besides stimulating the bone tissue formation, it also inhibits the bone loss through inhibiting the bone resorption and osteoclast formation. Thus, taurine acts as a double agent. In addition to these two major actions of taurine in bone, it also has beneficial effect in wound healing mld bone repair. Taurine possess radioprotective properties, too. As it is a naturally available molecule, it can be used as a preventive agent. Taurine has a potential to replace bisphosphonates which are currently in use for the inhibition of bone loss but this needs in depth study. As taurine is involved in bone formation and inhibition of bone loss, a detailed study can make it a single marker of bone metabolism. All these taurine-bone interaction is a symbol of their deep involvement but still require further extension to make taurine as a choice for tile sound bone health.