To understand the effect of high pressure on nitrogen oxides (NOx) formation in water added methane flames, opposed nonpremixed Water-methane/air (H2O-CH4/air) flames are numerically studied with high initial pressure. With GRI 3.0 detailed kinetic mechanism, NOx emissions are predicted for various strain rates. Due to high pressure, the chemical species are distributed in a narrow region, which means the thickness of the flame is thin. This can be clearly seen with high strain rate. Elevated pressure increases maximum temperature of flames which results in increased NOx emission. Even with elevated initial pressure, NOx emissions for H2O added methane flames are significantly decreased compare to pure methane flame. In addition, increased strain rate is also significant factor for decreasing NOx emission. With detailed rate of production analysis, in case of high pressure, it is confirmed that NO2 pathway is the most dominant reaction pathway than any other pathways.

The effect of gasoline-ethanol blends on performance and NOx emission was investigated in a SI engine with port and direct fuel injection systems. The 1-D cycle simulation program of GT-Power was utilized to analyze the performance of thermodynamic cycle. The results showed that the brake torques are increased with the addition of ethanol to gasoline because of the improvements of volumetric efficiency. The engine with direct ethanol blends injection system has more power than that with port gaoline injection system, which is caused by the higher latent heat of ethanol.

본 연구는 이상적인 실험환경이 아닌 실제 일반국도(국도 3호선)를 분석 대상으로 실시간으로 수집된 교통자료와 NOx 대기 오염 측정 자료를 이용하여 이들 사이의 관계를 규명하고 그 특성을 분석하고자 한다. 또한 이러한 관계를 이용하여 현장에서 실제 적용이 가능하며 대기오염도를 모니터링을 할 수 있는 일반국도의 차량배출가스로 인한 NOx 대기오염도 추정 모형을 개발하고자 한다. 모형의 구축에 있어서 측정 장비 및 기타 변동요인으로 인한 특이점을 제거하기 위하여 로버스트 분석을 이용하였고 바람의 영향을 고려하지 않은 경우와 바람의 영향을 고려한 경우에 대해서 모형을 구축하였다. 본 연구의 결과는 교통정책 시행에 따른 차량배출가스로 인한 대기오염 현황을 파악하고 교통정책의 환경적 효과를 평가하는데 활용될 수 있을 것이다.

The Effects of cooled and hot EGR(exhaust gas recirculation) on the characteristics of smoke and NOx emission have been investigated using a single cylinder, water-cooled, four cycle, DI diesel engine at several loads and speeds. In this study, a manually controlled EGR system was installed on a agricultural diesel engine which was operated at various operating system. And, the effects of hot EGR and cooled EGR on smoke and NOx emission were compared. The results showed that cooled EGR method was more effective than hot EGR method on smoke and NOx emission.

This study was conducted to evaluate the emission characteristics of air pollutants from incineration facilities in Jeollanam-do. We selected 8 incineration facilities depend on type and the 19 items such as dust etc. were measured at the measurement hole for emission gas from air contamination control units. The range of emission concentrations for dust was 2.8 ~ 20.9 mg/Sm3 less than permissible air discharge standards. The results of 10 gaseous contaminants such as SOx was less than permissible air discharge standards. The range of emission concentrations for NOx was 13.4 ~ 120.0 ppm, less than permissible air discharge standards. As G facility was 112.4 ppm, 120.0 ppm, it exceeded emission standard (100 ppm) twice. The range of emission concentrations for HCl was ND ~ 85.300 ppm, B Facilitiy exceeded emission standard (20 ppm) as 85.300 ppm. The range of emission concentrations for NH3 was ND ~ 76.333 ppm, A, D, H Facility exceeded emission standard (30 ppm). The concentration of each facility was 42.416 ppm, 62.930 ppm, 76.333 ppm. The results of heavy metals (5 items) showed within emission standards. G facility is operating in condition that input of urea is 100 L/day. If input of urea were changed to 50 ~ 75 L/day, the operating cost of air pollution prevention facility can be reduced by 25% ~ 50%. In this study, the correlation between urea input and nitrogen oxides was statistically significant, but the correlation between urea input and ammonia showed insignificantly. Our research attempts to evaluate the emission characteristics of air pollutants from incineration facilities and to institute a reduction plan, an effective management of incinerators.

It is known that lowering of peak temperature of flame reduces NOx emission in combustion process. Low oxygenconcentration of diluted combustion air reduces peak flame temperature, but makes flame unstable. So increasing oftemperature of reactants is needed to enhance flame stability. Mixing of high temperature combustion gas with combustionair makes low oxygen concentration and increases air temperature simultaneously. Low oxygen concentration ofcombustion air reduces peak temperature of flame and increased air temperature makes flame stable by enhancement ofcombustion reaction. Special apparatus for recirculation of high temperature combustion gas should be needed, becausegeneral blower cannot be used to return the gas of almost 1,000oC. Air jet type recirculation apparatus has been developedand installed in a commercial scale of 7.2ton/day incinerator and estimated. Oxygen concentration and temperature ofair mixed with inhaled high temperature combustion gas by the apparatus are 16.24~17.78%, 384~512oC, respectively,in a steady state of incineration.

MILD (Moderate and Intense Low oxygen Dilution) combustion using high temperature exhaust gas recirculation is applied to solid fuels of dried sewage sludge and pulverized coal combustion to investigate the effect of reduction of NOx emission in a pilot scale combustor. High temperature exhaust gas recirculation is accomplished by entraining high temperature exhaust gas to air jets at just exit of the combustion chamber without a heat exchanger. High temperature exhaust gas recirculation makes the solid fuel flame stable and extremely uniform color and uniform temperature distribution. NOx concentration at the combustor exit was 62% and 40% less in the high temperature exhaust recirculation MILD combustion compared with the conventional combustion using air jet only for sewage sludge and pulverized coal respectively.

In the present study, MILD (Moderate and Intense Low oxygen Dilution) combustion technology is adopted as one of the most effective tool for reduction of NOx emission in solid fuel combustion. We tried to achieve MILD combustion using the high temperature exhaust recirculation without any heat exchanger for preheating air. High temperature exhaust recirculation is accomplished by entraining the high temperature exhaust gas to air jets at just exit of the combustion chamber. This high temperature exhaust recirculation could recirculate heat and inert exhaust gas simultaneously. MILD combustion using the recirculation of the high temperature exhaust gas is experimented to investigate the effect of low NOx emission for the recycled solid fuel of the dried sewage sludge and pulverized coal. NOx emission could be reduced drastically by using this advanced combustion technique. Maximum 68% and 57% of NOx reduction was achieved for sewage sludge and pulverized coal respectively, in the high temperature exhaust recirculation MILD combustion compared with the conventional combustion using air jet only. This type of MILD combustion makes the apparent flames of both solid fuels extremely uniform without high temperature flamelet.

The Kyoto Protocol, that had been in force from February 16, 2005, requires significant reduction in CO₂emissions for all anthropogenic sources containing transportation, industrial, commercial, and residential fields, etc, and automotive emission standards for air pollutants such as particulate matter (PM) and nitrogen oxides (NOx) become more and more tight for improving ambient air quality. This paper has briefly reviewed homogeneous charge compression ignition (HCCI) combustion technology offering dramatic reduction in CO₂, NOx and PM emissions, compared to conventional gasoline and diesel engine vehicles, in an effort of automotive industries and their related academic activities to comply with future fuel economy legislation, e.g., CO₂emission standards and corporate average fuel economy (CAFE) in the respective European Union (EU) and United States of America (USA), and to meet very stringent future automotive emission standards, e.g., Tier 2 program in USA and EURO V in EU. In addition, major challenges to the widespread use of HCCI engines in road applications are discussed in aspects of new catalytic emissions controls to remove high CO and unburned hydrocarbons from such engine-equipped vehicles.