• Title, Summary, Keyword: Exhaust gas temperature

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A study of hydrocarbon SCR(selective catalytic reduction) on Ag/γ-Al2O3 catalyst (Ag/γ-Al2O3 촉매상에서 탄화수소-SCR(Selective Catalytic Reduction) 연구)

  • Kim, Moon-Chan;Lee, Cheal-Gyu
    • Analytical Science and Technology
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    • v.18 no.2
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    • pp.139-146
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    • 2005
  • Removal of NO contained in automobile exhaust gas was accomplished by the non-selective catalyst reduction method. The catalysts were prepared through loading of a specific amount of Ag into ${\gamma}-Al_2O_3$. The conversion of $NO_x$ was studied by varying the temperatures, $O_2$ concentrations and $SO_2$ concentrations for the prepared catalysts. The influence of the structure of catalyst to $NO_x$ conversion was followed through the analysis of the physical properties of the prepared catalysts. Experiments were conducted on each of the catalysts by varying the reaction conditions to find an optimum condition. The catalyst $Ag/{\gamma}-Al_2O_3$ shows a highest $NO_x$ conversion when the Ag content was 2 wt% and a reaction temperature of about $450^{\circ}C$. and after conducting the experiments, samples of before and after experiments analyzed using XRD, XPS, TPR, and UV-Vis DRS experiments. The result indicated that when Ag oxide content could not be maintained well at high temperatures $NO_x$ conversion decreased.

Production of Dry Oxidant through Catalytic H2O2 Decomposition over Mn-based Catalysts for NO Oxidation (NO 산화를 위한 Mn계 촉매상 과산화수소 분해를 이용한 건식산화제 생성)

  • Jang, Jung Hee;Choi, Hee Young;Han, Gi Bo
    • Clean Technology
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    • v.21 no.2
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    • pp.130-139
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    • 2015
  • The NO oxidation process has been applied to improve a removal efficiency of NO included in exhaust gas. In this study, to produce a dry oxidant for the NO oxidation process, the catalytic H2O2 decomposition method was proposed. A variety of the heterogeneous solid-acidic Mn-based catalysts were prepared for the catalytic H2O2 decomposition and the effect of their physico-chemical properties on the catalytic H2O2 decomposition were investigated. The results of this study showed that the acidic sites of the Mn-based catalysts has an influence on the catalytic H2O2 decomposition. The Mn-based catalyst having the abundant acidic sites within the wide temperature range in NH3-TPD shows the best performance for the catalytic H2O2 decomposition. Therefore, the NO oxidation efficiency, using the dry oxidant produced by the H2O2 decomposition over the Mn-based catalyst having the abundant acidic properties under the wide temperature range, was higher than the others. As a remarkable result, the best performances in the catalytic H2O2 decomposition and NO oxidation was shown when the Mn-based Fe2O3 support catalyst containing K component was used for the catalytic H2O2 decomposition.

Fundamental Heat Analysis about the Thermoelectric Generation System Using the Waste Heat of Exhaust Gas from Ship (선박의 배기가스 폐열을 활용한 열전발전시스템에 관한 기초 열해석)

  • Kim, Myoung-Jun;Ga, Gwang-Jin;Chea, Gyu-Hoon;Kim, In-Seup
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.22 no.5
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    • pp.583-592
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    • 2016
  • IMO (International Maritime Organization) in the UN (United Nations) set up that aim at reducing $CO_2$ emission from ship by up to 30 percent until 2030. The final purpose of this study is the development of marine thermoelectric generation system using waste heat from vessel of internal combustion engines. Before the development of marine thermoelectric generation system, this paper carried out the fundamental heat analysis of marine thermoelectric generation system. It was able to obtain the valuable results about the efficiency improvement of the thermoelectric generation system. The results is as follows : 1) It was confirmed that the efficiency of thermoelectric generation system improves to 8.917 % with increasing the temperature difference of peltier module by reducing the temperature difference between peltier module and heat source at the hot side. 2) System efficiency according to change in the external load resistance was confirmed that the change width of about 6 % which does not significantly occur. 3) System efficiency in the case stainless steel at the same condition is 8.707 %. System efficiency could be confirmed that the stainless steel is higher than duralumin (8.605 %), copper (8.607 %).

Flavor Entrapment Effect of Porous Starch and Sensory Characteristic of Boiled Instant Noodles Using Flavor-entrapped Porous Starch (다공성 전분의 향포접 효율과 이를 활용한 생면의 관능적 특성)

  • Kim, Hae-Yeun;Lee, Gyu-Hee;Kang, Hyun-Ah;Shin, Myung-Gon
    • Korean Journal of Food Science and Technology
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    • v.39 no.6
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    • pp.658-662
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    • 2007
  • In this study, wild sesame leaf aromas (WSLA) were extracted and the extracted aromas were entrapped in porous potato starch micelles. The entrapped aromas did not evaporate, even by heated water treatments, and remained until a physical treatment such as chewing. Thus, the entrapped WSLA starch was used to make precooked instant noodles in order to mask or/and reduce an unpleasant raw flour flavor. The efficiencies of the flavor entrapment were analyzed using gas-chromatography equipped with solid phase micro-extraction (SPME), as well as by sensory evaluation. The highest yield of the porous potato starch was shown as 82.4% at an inlet temperature (IT) of $170^{\circ}C$, an exhaust temperature (ET) of $90^{\circ}C$, and a feeding rate (FR) of 40 mL/min. In the porous starch made by IT at $200^{\circ}C$, ET at $100^{\circ}C$, and FR at 50 mL/min, the entrapment efficiency was 68% by GC analysis; this starch also had the highest WSLA and consumer acceptability, but the lowest raw flour flavor, according to the sensory evaluation results.

Effect of Thermophilic Ammonium Tolerant Bacteria on Malodors Emission of Composting of Pig Manure (돈분 퇴비화 과정중 악취물질에 대한 고온성 암모니움 내성균 접종 효과)

  • Seo, Myung-Chul;Kuroda, Kazutaka;Hanajima, Dai;Haga, Kiyonori
    • Korean Journal of Soil Science and Fertilizer
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    • v.31 no.1
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    • pp.77-84
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    • 1998
  • In order to investigate microbiological control of malodors, particularly including ammonia, the effect of three thermophilic ammonium tolerant bacteria strains. TAT112. TAT117 and TAT119, were tested during composting of pig manure in the laboratory scale composters. The total weight, volatile solids and BOD of the pig manure compost were decreased during composting process in all treatments. The temperature in all treatments rose in first 3 days dramatically, but that in control without inoculation reached its maximum most lately among the treatments. The nitrogen content of drain water accumulated inside and outside composter, and trapped in 6N $H_2SO_4$ was lower in TAT112 inoculated composter than in control. However, it was not lower in the treatment of TAT117 and TAT119 inoculated. Ammonia concentration in the exhaust gas monitored everyday during composting also demonstrated that it was lowest at TAT112 inoculated among all treatments. It was appeared to have an effect on reducing ammonia emission at the treatment of TAT112 inoculated than the control.

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The properties of algal degradation and gas emission by thermophilic oxic process (고온호기발효장치를 이용한 조류 분해 및 가스 발생특성)

  • Kang, Changmin
    • Journal of the Korea Organic Resources Recycling Association
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    • v.7 no.2
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    • pp.57-64
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    • 1999
  • The purpose of this study is to establish effective conditions for controlling $CH_4$, $N_2O$ emission from organic Waste / wastewater treatment processes. Continuous and batch experiments were conducted to treat the micro algae from polluted and eutrophicated lakes through the thermophilic oxic process. The microalgae used were mainly Microcystis sp.(collected from eutrophic lake) and Chlorella sp. (cultured in laboratory) Wasted cooking oil was added by aid-heating source. Physico-chemical components of sludges and microalgae were analyzed. In batch experiments, air supply was changed from 50ml/min to 150ml/min. The temperature. water content and drained water were affected by the air flow rate at initial stage. However, there was almost no influence of air flow rate on them in middle and last stages. At air flow rate of 100ml/min, the degradation rate of organic material was higher than that at other air flow rates. $CO_2$ concentration in exhaust was proportional to the strength of aeration, especially at initial stage when degradation was active. $CH_4$ with low concentration was detected only at starting stage when air diffusion was not enough. $N_2O$ production was not affected by variation of air supply. In continuous experiments no matter what the dewatering methods (with PAC and without PAC) and media (wood chip and reed chip) were changed, $N_2O$ was almost not affected by variation of injected air. Result showed that the reed chips using for lake purification could be used as media for thermophilic oxic process in lake and marshes area. $CO_2$ concentration was not so much affected by the change of dewatering methods and media types. $CH_4$ was not detected in the experimental period. So it can be shown that the thermophilic oxic process had been well operated in wide handling conditions regardless of media and dewatering methods.

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Evaluation of the corrosion property on the welded zone of forged steel piston crown with types of filler metals (용접재료별 단강 피스톤 크라운 용접부위의 부식특성에 대한 평가)

  • Moon, Kyung-Man;Won, Jong-Pil;Lee, Myeong-Hoon;Baek, Tae-Sil;Kim, Jin-Gyeong
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.4
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    • pp.409-417
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    • 2014
  • Since the oil price has been significantly jumped for recent some years, the diesel engine of the merchant ship has been mainly used the heavy oil of low quality. Thus, it has been often exposed to severely corrosive environment more and more because temperature of the exhaust gas in a combustion chamber is getting higher and higher with increasing of using the heavy oil of low quality. As a result, wear and corrosion of most parts surrounded with combustion chamber is more serious compared to the other parts of the engine. Therefore, an optimum weldment for these parts is very important to prolong their lifetime in a economical point of view. In this study, four types of filler metals such as Inconel 625, 718, 1.25Cr-0.5Mo and 0.5Mo were welded with SMAW and GTAW methods in the forged steel which would be generally used with piston crown material. And the corrosion properties of weld metal, heat affected zone and base metal were investigated using electrochemical methods such as measurement of corrosion potential, anodic polarization curves, cyclic voltammogram and impedance etc. in 35% H2SO4 solution. The weld metal and base metal exhibited the best and worst corrosion resistance in all cases of filler metals. In particular, the weld metal welded with filler metals of Inconel 718 revealed the best corrosion resistance among the filler metals, and Inconel 625 followed the Inconel 718. Hardness relatively indicated higher value in the weld metal compared to the base metal. Furthermore, Inconel 625 and 718 indicated higher values of hardness compared to 1.25cr-0.5Mo and 0,5Mo filler metals in the weld metal.

Characteristics of RDF Char Combustion in a Bubbling Fluidized Bed (기포 유동층 내에서 RDF 촤의 연소 특성)

  • Kang, Seong-Wan;Kwak, Yeon-Ho;Cheon, Kyoung-Ho;Park, Sung Hoon;Jeon, Jong-Ki;Park, Young-Kwon
    • Applied Chemistry for Engineering
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    • v.22 no.4
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    • pp.429-432
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    • 2011
  • The feasibility of applications of the char obtained from a gasification process of municipal-waste refuse derived fuel (RDF) as an auxiliary fuel was evaluated by combustion experiments. The higher heating value of the RDF char was 3000~4000 kcal/kg and its chlorine content was below the standard requirement demonstrating its potential as an auxiliary fuel. In the combustion exhaust gas, the maximum $NO_x$ and $SO_2$ concentrations were 240 ppm and 223 ppm, respectively. If an aftertreatment is applied, it is possible to control their concentrations low enough to meet the air pollutant emission standard. The HCl concentration was relatively high indicating that a care should be taken for HCl emission from the combustion of RDF. Based on the temperature distribution within the reactor, the concentration change of $O_2$ and $CO_2$, and the amount and the loss on ignition of solid residue, it was inferred that the combustion reaction was the most reliable when the excess air ratio of 1.3 was used.

Evaluation of the Corrosion Property on the Welded Zone of Cast Steel Piston Crown with Types of Electrode (용접재료 별 주강 피스톤 크라운 용접부위의 부식 특성에 대한 평가)

  • Moon, Kyung-Man;Kim, Yun-Hae;Lee, Myeong-Hoon;Baek, Tae-Sil;Kim, Jin-Gyeong
    • Journal of Ocean Engineering and Technology
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    • v.28 no.4
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    • pp.356-362
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    • 2014
  • Wear and corrosion of the engine parts surrounded with combustion chamber is more serious compared to the other parts of the engine because temperature of the exhaust gas in a combustion chamber is getting higher and higher with increasing of using the heavy oil of low quality. Therefore, an optimum repair weldment as well as an available choice of the base metal for these parts are very important to prolong their lifetime in a economical point of view. It reported that there was an experimental result for repair weldment on the forged steel which would be generally used with piston crown material, however, it is considered that there is no study for the repair weldment on the cast steel of piston crown material. In this study, four types of electrodes such as 1.25Cr-0.5Mo, 0.5Mo Inconel 625 and 718 were welded with SMAW and GTAW methods on the cast steel which would be generally used with piston crown material. And the corrosion properties of weld metal, heat affected zone and base metal were investigated using electrochemical methods such as measurement of corrosion potential, anodic polarization curves, cyclic voltammogram and impedance etc. in 35% $H_2SO_4$ solution. In the cases of Inconel 625, 718, the weld metals and base metals exhibited the best and worst corrosion resistance respectively, however, 1.25Cr-0.5Mo and 0.5Mo indicated that corrosion resistance of the base metal was better than the weld metal. And the weld metal welded with electrodes of Inconel 625 revealed the best corrosion resistance among the electrodes, and Inconel 718 followed the Inconel 625. Hardness relatively also indicated higher value in the weld metal compared to heat affected zone and base metal. In particular, Inconel 718 indicated the highest value of hardness compared to other electrodes in the heat affected zone.

Research for Performance Improvement of De-NOx of Cu-SCR Catalysts (Cu-SCR 촉매의 De-NOx 성능 향상을 위한 연구)

  • Seo, Choong-Kil
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.3
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    • pp.112-118
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    • 2018
  • In order to meet the strict emission regulations for internal combustion engines based on fossil fuel, the proportion of after-treatments for vehicles and vessels is gradually increasing. Diesel engines have high power, good fuel economy, and lower $CO_2$ emissions, and their market shares are increasing in commercial vehicles and passenger cars. However, NOx is generated in the localized high-temperature combustion regions, and particulate matter is formed in the zones of diffusion combustion. LNT and urea-SCR catalysts have been developed for after-treatment of the exhaust gas to reduce NOx in diesel vehicles. This study aims to improve the NOx reduction performance of Cu SCR catalyst, which is widely used in light, medium, and heavy-duty diesel engines. The de-NOx performance of $5Cu-2ZrO_2$/93Zeolyst(Si/Al=13.7) SCR catalyst was about 5-50% higher than that of $5Cu-2ZrO_2$/93Zeolite(Si/Al=2.9) at catalyst temperatures of $300^{\circ}C$ or higher. The zeolite had lower metal dispersion than zeolyst, and the reaction rate of the catalyst decreased as the average particle size increased. The $10Cu-2ZrO_2$/88Zeolyst catalyst loaded with 10wt% Cu had the highest NOx conversion rate of 40% at $200^{\circ}C$ and about 65% at $350^{\circ}C$. The ion exchange rate of Cu ions increased with that of Al, the crystalline compound of zeolite, and the de-NOx performance was improved by 20-40% compared to other catalysts.