• 한국수소및신에너지학회논문집
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• 제34권1호
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• pp.38-46
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• 2023

Carbon neutrality policies have been strengthened to reduce emissions, and the importance of technology road maps has been emphasized. In the global industrial boiler market, carbon neutrality is implemented through fuel diversification of methane-hydrogen mixture gas. However, various problems such as flashback and flame unstability arise. There is a limit to implementing the actual system as it remains in the early stage. Therefore, it is necessary to secure the source technology of methane-hydrogen hybrid combustion system applicable to industrial fields. In this study, control program for methane-hydrogen fuel conversion was developed to expect various parameters. After determining the hydrogen mixing ratio and the input air flow, the fuel conversion control algorithm was constructed to get the parameters that achieve the target oxygen concentration in the exhaust gas. LabVIEW program was used to derive correlations among hydrogen mixing rate, oxygen concentration in exhaust gas, input amount of air and heating value.

• 유통과학연구
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• 제18권9호
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• pp.67-75
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• 2020

Purpose: The purpose of this study is to enhance sales promotion efficiency for using solid refuse fuel facilities. Renewable energy technology using Solid Refuse Fuel (SRF) is an economic efficiency technology that recovers waste by burning various wastes. A survey on the pollutants discharged from the solid fuels facilities was investigated so that the SRF facilities could be expanded, distributed and reflected in the policy. Research design, data, and methodology: In this study, 9 business sites using SRF and Bio-SRF as main raw materials were investigated for 2 years. The characteristics of target business sites such as the type of fuel used, combustion method, combustion temperature, daily fuel consumption and environmental prevention facilities were studied. Results: The average pollution & ammonia concentration of Bio-SRF facilities was found to be 88.15% higher than that of SRF facilities. But the average acetaldehyde concentration of SRF facilities was found to be 88.15% higher than that of Bio-SRF facilities. Conclusions: The main issue is how much electric power generation using combustible materials affects air pollution. The waste recycling law provides the standard value according to the fuel property, but there is a considerable gap with the mixed fuel. Therefore, for efficient utilization of facilities using solid fuel products, additional research is needed to improve the distribution structure of exhaust pollutants is needed.

• 대한기계학회논문집B
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• 제33권3호
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• pp.207-214
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• 2009

Crossover of nitrogen from cathode to anode is inevitable in typical membranes used in PEM fuel cells. This crossovered nitrogen normally accumulates in the hydrogen recirculation system at anode side channels. Excessive buildup of nitrogen in the anode side lowers the relative hydrogen concentration and finally affects the performance of fuel cell stack. So it is very important to analysis the nitrogen gas crossover at various operating conditions. In this study, characterization of nitrogen gas crossover in PEM fuel cell stack was investigated. The mass spectroscopy (MS) has been applied to measure the amount of the crossovered nitrogen gas at the anode exit. Results show that nitrogen gas crossover rate was affected by current density, anode and cathode stoichiometric ratio and operating pressure. Current density, anode stoichiometric ratio and anode operating pressure do not affect nitrogen crossover rate but anode exit concentration of nitrogen. Cathode pressure and stoichiometric ratio largely affect the nitrogen crossover rate.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
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• pp.337-339
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• 2012

This study investigates the combustion and heat transfer characteristics of a 100MWe pulverized coal boiler retrofitted for demonstration of oxy-coal combustion. By computational fluid dynamics (CFD), the flame temperature and wall heat flux were compared for air-fuel and oxy-fuel combustion with different $O_2$ concentration in the oxidizers. It was found that the oxy-fuel combustion requires an $O_2$ concentration higher than 27 vol.% for the boiler to achieve the similar value of wall heat flux with air-fuel combustion.

• Environmental Engineering Research
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• 제22권2호
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• pp.157-161
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• 2017

Simultaneous treatment of food waste leachate and power generation was investigated in an air-cathode microbial fuel cell. A TCOD removal efficiency of $95.4{\pm}0.3%$ was achieved for an initial COD concentration of 2,860 mg/L. Maximum power density ranged was maximized at $1.86W/m^3$, when COD concentration varied between 60 mg/L and 2,860 mg/L. Meanwhile, columbic efficiency was determined between 1.76% and 11.07% for different COD concentrations. Cyclic voltammetric data revealed that the oxidation peak voltage occurred at -0.20 V, shifted to about -0.25 V. Moreover, a reduction peak voltage at -0.45 V appeared when organic matters were exhausted, indicating that reducible matters were produced during the decomposition of organic matters. The results showed that it was feasible to use food waste leachate as a fuel for power generation in a microbial fuel cell, and the treatment efficiency of the wastewater was satisfied.

• 디지털융복합연구
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• 제10권2호
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• pp.225-229
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• 2012

소형발전용 연료전지 시스템에 있어 개질장치는 탄화수소계의 연료를 수소가 풍부한 가스로 개질하여 주는 장치이다. 개질장치는 시스템 전체의 안정성과 성능의 관점에서 중요한 핵심 지표를 가지게 되는데 개질기의 핵심평가지표 중 가장 중요한 것은 배출가스 중의 CO농도이다. 시스템의 효율, 성능 및 안정성을 위하여 CO농도를 5ppm 이하로 관리되어야 한다. 본 연구에서는 개질기의 배출가스 내의 CO농도에 영향을 미치는 핵심인자를 도출한다. 개질기의 운전 및 설계에 있어 six-sigma 기법 중의 실험계획법을 도입하여 CO 농도에 영향을 미치는 핵심인자들을 도출해내고 도출된 인자들의 개선을 통하여 최적화된 운전조건을 제시하였다. 연료전지용 개질기에 있어서 가장 중요한 CO의 농도를 제어하기 위하여 도출된 인자들은 MTS, LTS, Prox와 같은 각 개질기내의 온도제어 및 그에 관한 결과로서의 CO 농도에 대한 최적 운전조건을 도출하였다.

• 한국자동차공학회논문집
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• 제11권3호
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• pp.20-27
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• 2003

In this paper, the fuel transport characteristics during transient condition was studied by using a Fast Response Flame Ionization Detector(FRFID). The quantitative measurement method for the inducted fuel mass into cylinder is studied. The inducted fuel mass into the cylinder was estimated by using calculated air-fuel ratio by hydrocarbon concentration of cylinder and air flow model. In order to estimate the transportation of injected fuel from the intake port into cylinder, the wall wetting fuel model was used. The two coefficient $\alpha$,$\beta$) of the wall-wetting fuel model was determined from the measured fuel mass that was inducted into the cylinder at the first cycle after injection cut-off To reduce an air/fuel ratio fluctuation during rapid throttle opening, the appropriate fuel injection rate was obtain from the wall wetting model with empirical coefficients. Result of air/fuel ratio control, air/fuel excursion was reduced.

• Nuclear Engineering and Technology
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• 제42권2호
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• pp.183-192
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• 2010

An electrochemical reduction of a mixture of metal oxides was conducted in a LiCl molten salt containing 3 wt% $Li_2O$ at $650^{\circ}C$. The oxide reduction was carried out by applying a current to an electrolysis cell, and the $Li_2O$ concentration was analyzed during each run. The concentration of $Li_2O$ in the electrolyte bulk phase gradually decreases according to Faraday's law due to a slow diffusion of the $O^{2-}$ ions. A hindrance effect of the unreduced metal oxides was observed for the reduction of the uranium oxide. Cs, Sr, and Ba of high heat-load fission products were diffused into and accumulated in the salt phase as predicted with thermodynamic consideration.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.137-142
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• 2001

The effects of acoustic excitation with various frequencies for combustion air as well as fuel on the combustion emission and local NO concentration in diffusion flame were investigated experimentally. It was studied to investigate the effects of combination between four frequencies for the fuel and various frequencies for the combustion air. The better characteristic for NO emission was revealed by acoustic exciting with frequencies for the air and the fuel excited at 0Hz and 120Hz and the generation of CO was decreased at low frequency for fuel and the excited combustion air. The amount of combustion emission could be controlled by acoustic exciting of the combustion air. And when both fuel and air are excited by some frequencies, the diffusion flame was affected by frequency which excited fuel in the middle of the flame and by air-exciting frequency at both sides of the flame. The local NO in the flame was generated much less at the condition that fuel was excited by frequencies than the condition was not.

• 한국수소및신에너지학회논문집
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• 제16권4호
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• pp.356-363
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• 2005

The purpose of this paper is to investigate the optimal condition of the Syngas production by reforming of fuel using plasmatron. Plasma was generated by air and arc discharge. The effects of applied steam, $CO_2$ or Ni-catalyst on fuel conversion, as well as hydrogen yield and $H_2$/CO ratio were studied. When the variations of $O_2$/fuel ratio, $H_2O$/fuel flow ratio and $CO_2$/fuel flow ratio were $0.94{\sim}1.48$, $4.3{\sim}10$ and $0.8{\sim}3.05$, respectively. Under the condition mentioned above, result of $H_2O$/fuel flow ratio was maximum $H_2$ concentration, or $28.2{\sim}31.6%$, and result of $H_2O$/fuel flow ratio with catalyst was minimum CO concentration or $6.6{\sim}7.1%$. and $H_2$/CO ratio were $3.89{\sim}4.86$.