• Journal of Chest Surgery
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• 제23권6호
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• pp.1049-1056
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• 1990

The OXYREX hollow fiber membrane oxygenator developed by joint work of KIST and Green Cross Medical company has been evaluated by experimental investigation and clinical application, In this oxygenator gas exchanges occur through small pores of 0.1pm size which are distributed on 70% of surface of polypropylene hollow fiber. The Oxyrex membrane oxygenator consists of 36 thousand hollow fibers and it has 3.3m2 of gas exchange surface. The Oxyrex membrane oxygenator has unique blood flow path: blood enters the oxygenator passes between the hollow fibers and exits through outlet ports, that provides low transmembrane pressure drop. In the animal experiment and in vitro investigations of Oxyrex oxygenator, it showed low transmembrane pressure difference, effective heat exchanger performance, stable gas transfer function and less blood trauma. The Oxyrex oxygenator been used from March, 1990, to October, 1990, in 40 patients undergoing open heart operations. In the clinical applications of Oxyrex, adequate oxygenation[PaO2, 283$\pm$70mmHg] and carbon dioxide removal[PaCO2, 27\ulcorner6mmHg]were maintained under the condition of FiO2: below 0.6, Hct; 25%, perfusion flow; 2.4 L/min, gas flow: 2.1 L/min. During maximum 365 minutes of cardiopulmonary bypass[CPB] time period, the Oxyrex oxygenator maintained stable condition of PaO2, PaCO2 respectively and it also kept low plasma hemoglobin level. The complement proteins C3 and CH50 were not significantly changed pre to post CPB. There were no complications related to the oxygenator during and after the CPB.

• Journal of Korean Society for Atmospheric Environment
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• 제23권2호
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• pp.203-213
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• 2007

Numerical analysis has been performed to understand flow characteristics in the reactor with bag filters in an integrated adsorption/catalytic process which can treat dioxin and $NO_{x}$ together. Computational fluid dynamics technique was employed with Euler-Lagrangian model to consider flue gas and activated carbon particles simultaneously, so that residence time of flue gas and activated carbon particle could be obtained from the numerical analysis directly. The numerical analysis has been performed with different three particle sizes and compared each flow characteristics with particle's size. Fundamental flow patterns of flue gas and activated carbon particles, pressure distribution, residence time of flue gas and activated carbon particles, and distribution of activated carbon have been obtained from the numerical analysis. Flow patterns of flue gas and activated carbon particles in the reactor were very complicated and they moved along very various paths. Therefore, their residence time in the reactor was also various. The results obtained would be effectively used to estimate the removal efficiency in the reactor once the residence time is combined with the reaction equation.

• Journal of Environmental Science International
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• 제22권11호
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• pp.1481-1498
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• 2013

The SCR (selective catalytic reduction) system is highly-effective technique for NOx reduction from exhaust gases. In this study, the effects of the direction and size of nozzle and the ammonia injection concentration on the performance of SCR system are analyzed by using the computational fluid dynamics method. When the nozzle is arranged in zigzaged direction which is normal to exhausted gas flow, it is shown that the uniformity of gas flow and the NH3/NO molar ratio is improved remarkably. With the change of the ammonia injection concentration from 0.2 vol%(wet) to 1.0 vol%(wet), the uniformity of gas flow shows a good results. As the size of nozzle diameter changes from 6 mm to 12 mm, the uniformity of gas flow is maintained well. It is shown that the uniformity of the $NH_3/NO$ molar ratio becomes better with decreasing the ammonia injection concentration and the size of nozzle diameter.

• Proceedings of the KSME Conference
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• 대한기계학회 2004년도 추계학술대회
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• pp.1686-1691
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• 2004

The effect of recirculated exhaust gas on performance and exhaust emissions with FGR rate are investigated by using a natural circulation, pressurized draft and water tube boiler with FGR system operating at several boiler loads and over fire air(OFA) damper openings. The purpose of this study is to apply the FGR system to a power plant boiler for reducing $NO_{x}$ emissions. To activate the combustion, the suction damper of two stage combustion system installed in the upper side of wind box is opened by handling the lever between $0^{\circ}$ and $90^{\circ}$ , and the OFA with 0 to 20% into the flame is supplied, as the combustion air supplied to burner is reduced. It is found that the fuel consumption rate divided by evaporation rate does not show an obvious tendency to increase or decrease with rising the FOR rate, and $NO_{x}$ emissions are decreased, at the same OF A damper opening, as FOR rates are elevated and boiler loads are dropped.

• Transactions of the Korean Society of Mechanical Engineers B
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• 제24권10호
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• pp.1294-1299
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• 2000

The combustion characteristics have been investigated to develop the 50 kW-class gas turbine combustor. The combustor design program was developed and applied to design this combustor. The combustion air which has the temperature of 45, 200, $300^{\circ}C$ were supplied to combustor for elucidating the effect of inlet air temperature on CO, NOx emissions and flame temperature. The exit temperature and NO were increased and CO was decreased with increasing inlet air temperature. Also, the effect of equivalence ratio was considered to verify the combustor performance. The emissions of CO and NO with inlet air temperature can be analyzed qualitatively by measuring the temperature inside the combustor. The combustion performance with fuel schedule was evaluated to get the informations of the starting and part loading process of gas turbine. The combustion was stable above the equivalence ratio of 0.18. The pattern factor which is the important parameter of combustor performance was satisfied with the design criterion. Consequently the combustor was proved to meet the performance goal required for the target gas turbine system.

• Journal of Hydrogen and New Energy
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• 제8권1호
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• pp.5-10
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• 1997

Because of environmental pollution and reserve limitations of fossil fuels, several alternative energies have been developing. One of them, the hydrogen is researched as a highly probable solution. In this study pure hydrogen gas and oxygen gas are burned in combustor to reduce the emission, and a gas turbine is used. Cooling water around the combustor recovers the cooling heat loss to useful work by being expanded from liquid to vapor, being injected into the combustor and making pressure rise with working fluid to get more turbine power. Because pure hydrogen and oxygen are used, there is no carbonic emission such as CO, $CO_2$, HC nor $NO_x$, and $SO_x$. The power is obtained by turbine system, which makes lower noise and vibration than any reciprocating engine. Running of a turbine is searched under various conditions of hydrogen flow rate and water injection rate. Maximum speed of the turbine is obtained when the combustion reaches steady state. It is enable to determine the optimum rate between hydrogen flow and water injection which makes turbine run maximum speed.

• Environmental Mutagens and Carcinogens
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• 제25권4호
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• pp.150-156
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• 2005

Analysis of chromosome aberration (CA) and cytokinesis-block micronucleus (CBMN) assay in peripheral lymphocytes of nurses exposed to low levels of anticancer drug and Ethylene Oxide(EO) gas in a hospital were performed. The frequency of CA was increased in the exposed compared to the controls whereas no increase of the frequency of MN was found. The frequencies of chromatid type CA were 1.2, 3.91 and 9.67 per 500 cells in the controls, workers exposed to anticancer drug and workers exposed to EO, respectively. Lower frequency of CA in nurses handling anticancer drugs with safety covers compared to those without safety covers was observed, but it was not statistically significant. The frequency of CA in nurses handling anticancer drugs increased by the frequency of mixing anticancer drugs. Poisson regression analysis showed a significant association of the frequency of chromatid type CA with age, duration of wort exposure to anticancer drug and EO gas exposure, but no association of the frequency of chromosome type CA with any variables. The results suggested that there were associations between CA and the occupational exposure to low levels of anticancer drug and EO gas.

• International Journal of Automotive Technology
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• 제2권4호
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• pp.123-133
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• 2001

An important goal in diesel engine research is the development of a means to reduce the emission of oxides of nitrogen ($NO_x$) and soot particulate. A phenomenological model based on the multizone concept is used in the current paper to analyze and compare the effects of exhaust gas recirculation (EGR) and split fuel injection on emission from a compression-ignited, direct-injection engine. The present results show that $NO_x$ can be reduced with a minimum penalty of soot particle emission with cooled EGR. Compared with EGR, split fuel injection has a higher soot penalty at a given level of $NO_x$ reduction.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.55-62
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• 2006

A two-step fuel-rich/fuel-lean catalytic combustion seems to be one of the most effective methods to control simultaneously the NO generation and the hydrocarbon (HC) conversion from fuel-bound nitrogen. By controlling equivalent air ratio for maintaining fuel-rich and fuel-lean condition over each catalytic layer, space velocity, inlet temperature, and catalyst component, the HCand ammonia conversion efficiency higher than 95% could be achieved, with ammonia conversion to NO remaining below 5%. The experimental results wouldbe applied to the combustion of land fill gas and to gasified refuse-derived fuels as a method of minimizing NO generation.

• Transactions of the Korean Society of Mechanical Engineers B
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• 제37권10호
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• pp.911-918
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• 2013

The combustion characteristics of an EV (Environmental Vortex) burner (double-cone burner) adopted in a gas turbines are numerically investigated. The mixing of fuel and air is analyzed for reduction of NO emission. To predict the correlation between NO emission and fuel-air mixedness, 1-step and 2-step chemistry models are adopted. The results calculated by 1-step chemistry showed that NO emissions increased by 2% in the case of degraded mixedness and by 169% in the case of improved mixedness, where the temperature in the flame zone was overestimated upstream of the cone. However, the corresponding results calculated by 2-step chemistry showed that NO emission increased by 3% and decreased by 5%, where the flame zone was not formed inside the cone. The latter results agree well with the experimental ones indicating an increase of 63% and decrease of 11% in the respective cases. Despite quantitative errors, NO emissions can be predicted reasonably by the application of the 2-step chemistry model adopted here and design modification of burner for NO reduction can be proposed based on the numerical data.