• Title/Summary/Keyword: NOx Reduction Ratio

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Fundamental Study on Applying an Integral TiO2 Solution to Asphalt Pavement (1액형 광촉매를 아스팔트 포장에 적용하기 위한 기초연구)

  • Park, Jaeyoung;Kim, Young;Kim, Hyeok-Jung;Hwang, Yong-Kyung;Lee, Jaejun
    • International Journal of Highway Engineering
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    • v.19 no.1
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    • pp.53-62
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    • 2017
  • PURPOSES : This research was a fundamental study on the application of an integral $TiO_2$ solution to asphalt concrete pavement. The integral $TiO_2$ solution was produced in pilot production equipment; application of the integral $TiO_2$ solution to asphalt pavement was conducted to examine the pollution-reducing capability of photocatalytic compounds such as $TiO_2$. The photocatalytic $TiO_2$ reacted with air pollutants, converting them into small amounts of relatively benign molecules. METHODS : In this study, laboratory experiments were conducted using five various testing methods. Tensile strength ratio (TSR) and British pendulum test (BPT) were conducted in order to evaluate the properties of asphalt pavement subsequent to the integral $TiO_2$ solution coating. In addition, methylene blue testing, a measurement of nitrate on the coated pavement, and nitrogen oxide (NOx) reduction testing were conducted in order to evaluate photocatalytic reaction. Lastly, a UV-A lamp was used as a light source for photocatalytic reactions. RESULTS : Test results indicated no change in the properties of asphalt pavement following the integral $TiO_2$ solution coating. In order to evaluate the performance of asphalt pavement as a function of $TiO_2$, the moisture susceptibility and skid resistance were investigated. The moisture susceptibility and skid resistance satisfied there quirements related to pavement quality and safety specification. Furthermore, the effects of reduction of air pollution were significantly improved as determined via the methylene blue test and NOx reduction test. The $TiO_2$-paved asphalt specimen exhibited approximately 43% reduction of NOx. CONCLUSIONS : This study has suggested that applying $TiO_2$ rarely impacts asphalt pavement performance measures such as moisture susceptibility and skid resistance, and that its application may be a better means of reducing air pollution. Further studies, such as proper $TiO_2$ dosage rates and compatibility with various pavement types, are required to broaden and generalize its application.

Experimental Study on Thermal NOx and CO Emission in a Laboratory-Scale Incinerator with Reversed Secondary Air Jet Injection (역방향 2차 공기 주입 방식을 적용한 소각 연소로의 Thermal NOx 및 CO 배출특성에 대한 축소모형실험 연구)

  • Choi, Chonggun;Choi, Woosung;Shin, Donghoon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.8
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    • pp.503-510
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    • 2016
  • Incinerators generally emit pollutants such as NOx and CO during the combustion process. In this paper, pollutant emissions and temperature distributions were studied in a simulated incinerator with a reversed (relative to the flue gas flow) secondary air injection system. The experiments were performed by using a lab-scale furnace in order to evaluate the effects of the injection location, direction and flow rate of secondary air jets. The emission of NOx was lower in the case of reversed secondary air injection than in the case of cross injection, due to the recirculation and mixing of the exhaust gas. In the reversed air injection cases, thermal NOx emissions decreased as secondary air ratio increased from 30 to 60 and slightly increased at secondary air ratios higher than 60. In most cases, CO emissions were not detected except for a few reversed secondary air injection cases, in which cases CO concentrations below 2ppm were observed.

Nitrogen Oxides Removal Characteristics of SNCR-SCR Hybrid System (SNCR-SCR 하이브리드 시스템의 질소산화물 제거 특성)

  • Cha, Jin Sun;Park, Sung Hoon;Jeon, Jong-Ki;Park, Young-Kwon
    • Applied Chemistry for Engineering
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    • v.22 no.6
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    • pp.658-663
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    • 2011
  • The SNCR-SCR (selective non-catalytic reduction-selective catalytic reduction) hybrid system is an economical NOx removal system. In this study, the effect of the operating parameters of the SNCR-SCR hybrid system on NOx removal efficiency was investigated. When the SNCR reactor was operated at a temperature lower than the optimum temperature ($900{\sim}950^{\circ}C$), an additional NO removal is obtained basesd on the utilization of $NH_3$ slip. On the other hand, the SNCR reactor operated above the temperature resulted in no additional NO removal of SCR due to decomposition of $NH_3$. Therefore, the SNCR process should be operated at optimum temperature to obtain high NO removal efficiency and low $NH_3$ slip. Thus, it is important to adjust NSR (normalized stoichiometric ratio) so that $SR_{RES}$ can be maintained at an appropriate level.

A Study of Emulsion Fuel of Cellulosic Biomass Oil (목본계 바이오매스오일의 에멀젼 연료화 연구)

  • Kim, Moon-Chan
    • Journal of the Korean Applied Science and Technology
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    • v.33 no.4
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    • pp.836-847
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    • 2016
  • Water soluble oil was obtained by pyrolysis of biomass. The characteristics of emulsified fuel by mixing water soluble oil and MDO(marine diesel oil) and engine emissions were studied with engine dynamometer. Saw dust was used as biomass. Water soluble oil was obtained by condensing of water and carbon content with pyrolysis of saw dust at $500^{\circ}C$. Emulsion fuel was obtained by emulsifying MDO and water soluble oil by the water soluble oil mixing ratio of 10 to 20% of MDO. Exhaust gas detection was performed with engine dynamometer. While combustion, micro-explosion took place in the combustion chamber by water in the emulsion fuel, emulsion fuel scattered to micro particles and it caused to smoke reduction. The heat produced from water vapour reduce the temperature of internal combustion chamber and it caused to inhibition of NOx production. It can be verified by the lower exhaust temperature of each ND-13 mode using emulsion fuel than that of MDO fuel. The NOx and smoke concentration were reduced by increasing water soluble oil content in the emulsion fuel. The power also decreased according to the increment of water soluble oil content of emulsion fuel because emulsion fuel has low calorific value due to high water content than MDO. As a result of ND-13 mode test with 20% bio oil content, it was achieved 25% reduction in NOx production, 60% reduction in smoke density, and 15% reduction in power loss.

A Study on the Improvement of Diesel NOx Conversion Efficiency by Increasing the Ammonia Amount Adsorbed in a SCR Catalyst (디젤엔진 요소수 분사 SCR 시스템에서 촉매 내 암모니아 흡장량의 증가에 따른 NOx 저감효율 향상 특성에 관한 연구)

  • Kim, Yanghwa;Lim, Ockteack;Kim, Hongsuk
    • Journal of ILASS-Korea
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    • v.25 no.4
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    • pp.196-203
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    • 2020
  • Nowadays, urea SCR technology is considered as the most effective NOx reduction technology of diesel engine. However, low NOx conversion efficiency under low temperature conditions is one of its problems to be solved. This is because injection of UWS (Urea Water Solution) is impossible under such a low temperature condition due to the problem of insufficient of urea decomposition and urea deposits. In several previous studies, it has been reported that appropriate control of the amount of ammonia adsorbed on SCR catalyst can improve the NOx conversion efficiency under low temperature conditions. In this study, we tried to find out how much the NOx conversion efficiency increases with respect to the amount of ammonia adsorbed on the catalyst, and what the temperature conditions that the ammonia slip occurs. This study shows the results of 8 times repeated WHTC test with a diesel engine, in which UWS was injected with NH3/NOx mole ratio of '1'. Through this study, it was found that 13% of the NOx conversion efficiency of WHTC increased while the θ (ammonia adsorption rate) increased from "0%" to "22%". In addition, it is found that in cases of high θ value, the significant improvement of NOx conversion efficiency at low temperatures presented during the beginning period of WHTC and at high temperature and transient conditions presented during last part of WHTC test. The NH3 slip occurring condition was 250℃ of catalyst temperature and 10% of θ, and the amount of NH3 slip increased as the temperature and θ are increased.

Exhaust Gas Recirculation Control in a Spark-Ignition LPG Engine Using Neural Networks

  • Cui, Hongwei;Liu, Vifang;Zhai, Yujian
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.68.3-68
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    • 2002
  • This paper presents a neural network approach to control exhaust gas recirculation(EGR) in a Liquefied Petroleum Gas(LPG) engine. In order to meet Increasingly stringent automotive exhaust emission regulations, alternative fuels such as LPG engines have been developed in many countries. HC&CO emissions of LPG engines can be easily reduced through air-fuel ratio control, but the control effect on NOx reduction is not good enough. Consequently EGR system is introduced to achieve a significant reduction in NOx emissions. Conventional EGR control uses the mapping method. The calibration time is long and the work is complex when adopting this mapping method. However neural networks are suitable f...

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Emission Characteristics of a Gasoline Engine Using Ethanol Blended Fuel (가솔린 기관의 에탄올혼합연료의 배출가스 특성에 관한 연구)

  • 조행묵;정동화
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.3
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    • pp.516-521
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    • 2004
  • In this paper, the effects of ethanol blended gasoline on emissions and their catalytic conversion efficiencies characteristics were investigated in gasoline engine with an electronic fuel injection. The results showed that the increase of ethanol concentration in the blended fuels brought the reduction of THC and $CO_2$ emissions from the gasoline engine. THC emissions were drastically reduced up to thirty percent. And brake specific fuel consumption was increased. but brake specific energy consumption was similar level. However. unburned ethanol and acetaldehyde emissions increased. The conversion efficiency of Pt/Rh based three-way catalysts and the effect of ethanol on CO and NOx emissions were investigated by the change of engine speed. load and air/fuel ratio. Furthermore, the ethanol blended fuel results in the reduction effect of THC. CO and NOx emissions at idle speed.

Emission characteristics of Natural Gas Fueled Vehicl and its Purification Technologies (천연가스 자동차의 Emission 배출특성 및 저감법)

  • 최병철;이지연;손건석;이귀영
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.2
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    • pp.127-135
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    • 1997
  • Experiments have been conducted to investigate emission characteristics of compressed natural gas fueled vehicle(CNGV) by the FTP 75 mode test. Its purification technologies were also investigated. It was found that CNGV was operated on the rich A/F condition by comparison with gasoline vehicle. The Pd catalyst was higher in methane purification performance than Pt and Pd/Pt/Rh catalysts. Up to 60% portion of the accumulative HC emissions(that contains above 80% methane) form CNGV occurs during the first phase of the FTP 75 mode. CO that is exhausted at rich conditions of the air-fuel ratio more than lean conditions should be used for the catalytic reduction of NOX, because the methane is not the effective reduction for NOX in the CNGV with 3-way catalyst system.

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Combustion Characteristics of Premixed Charge Compression Ignition Diesel Engine using Mixed Fuels (혼합연료를 이용한 예혼합 압축착화 디젤엔진의 연소특성)

  • 조병호;이기형;이창식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.5
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    • pp.58-64
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    • 2002
  • A diesel engine has various merits such as high thermal-efficiency, superior fuel consumption and durability. Therefore the number of diesel engine in the world is increasing. As the seriousness of environmental pollution increases in the world, the method to reduce the noxious materials of CO2, NOx and P.M. is very important subject to correspond to exhaust gas regulations. A new concept, so called premixed charge compression ignition(PCCI), is focused among the various corresponding manners. In this study, we investigated the combustion characteristics of PCCI engine using a mixed fuels with that of commercial diesel engine. Finally we grasped a emission characteristics of PCCI engine. From this experiment, it could be found that NOx reduction is caused by the lower maximum temperature and soot reduction is caused by rapid combustion under diffusion combustion part. Also, it was found that 1st-combustion(cool flame) and 2nd-combustion(hot flame) is appeared in heat release curve, exhaust gas temperature is diminished and combustion variation is increased according to increasing of gasoline ratio.