• Title/Summary/Keyword: catalytic efficiency

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Effect of the De-NOx Facility Operating Condition on NOx Emission in a 125 MW Wood Pellet Power Plant (125 MW급 우드펠릿 발전소에서 탈질설비 운전조건이 질소산화물 발생량에 미치는 영향)

  • Jeon, Moonsoo;Lee, Jae-Heon
    • Plant Journal
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    • v.18 no.3
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    • pp.52-61
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    • 2022
  • This study tested the effect of de-NOx Facility operating condition on Nox emisiion in a 125 MW wood pellet power plant in Yeongdong Eco Power Plant Unit 1, which is in operation. As SNCR urea flow rate increased, NOx emission gradually decreased, but ammonia slip after SCR increased. The boiler under test has a structure that is unfavorable to SNCR operation due to the high internal temperature, and the optimum location of the nozzle will be required. SCR dilution air temperature change did not affect the amount of NOx generated. Increasing SCR ammonia flow reduced the NOx emission at SCR outlet and also increased the NOx removal efficiency. However, the ammonia flow rate of 111 kg/h, which does not exceed the ammonia slip its own reference limit, is estimated to be the maximum operating standard. The increase in SCR mixer pressure reduced NOx emission and the removal efficiency was also measured to be the most effective variable to inhibit NOx production.

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NOx Removal of NH3-SCR Catalysts with Operating Conditions (공정조건에 따른 NH3-SCR용 촉매의 질소산화물 제거특성)

  • Park, Kwang Hee;Cha, Wang Seog
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.11
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    • pp.5610-5614
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    • 2012
  • Performance of catalyst was studied with various operating conditions for selective catalytic reduction of $NO_x$ with $NH_3$. It is confirmed that catalysts containing Mn and Cu have a good efficiency in the usage of oxygen by the $H_2$-TPR analysis. In the case of catalyst #1, $NO_x$ conversion was decrease with the increase of reaction temperature. But in the case of catalyst #2, $NO_x$ conversion was increased and then remained constant with the increase of reaction temperature. This phenomenon is due to the difference of the $NH_3$ oxidation of both catalysts.

Heterologous Expression of Lignin Peroxidase H2 in Escherichia coli: In Vitro Refolding and Activation

  • Lee, Dong-Ho;Kim, Dong-Hyun
    • BMB Reports
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    • v.32 no.5
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    • pp.486-491
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    • 1999
  • An engineered cDNA from Phanerochaete chrysosporium encoding both the mature and propeptide-sequence regions of lignin peroxidase H2 (Lip H2) was overexpressed in Escherichia coli BL21 (DE3) to evaluate its catalytic characteristics and potential application as a pollution scavenger. All expressed proteins were aggregated in an inactive inclusion body, which might be due to inherent disulfide bonds. Active enzyme was obtained by refolding with glutathione-mediated oxidation in refolding solution containing $Ca^{2+}$, heme, and urea. Propeptide-sequence region was not processed as evidenced by N-terminal sequence analysis. Recombinant Lip H2 (rLip H2) had the same physical properties of the native protein but differed in the $K_{cat}$. Catalytic efficiency ($k_{cat}/K_m$) of rLip H2 was slightly higher than that of the native enzyme. In order to express an active protein, fusion systems with thioredoxin or Dsb A, which have disulfide isomerase activity, were used. The fused proteins expressed by the Dsb A fusion vector were aggregated, whereas half of the thioredoxin fusion proteins were recovered as a soluble form but still catalytically inactive. These results suggest that Lip H2 may not be expressed as an active enzyme in Escherichia coli although the activity can be recovered by in vitro refolding.

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Comparative properties for serial-parallel connection of DSC with CNT and pt counter electrodes (CNT와 Pt 상대전극을 가지는 염료감응형 태양전지의 직렬 ${\cdot}$ 병렬 연결에 따른 특성비교)

  • Choi, Jin-Young;Hong, Ji-Tae;Kim, Mi-Jeong;Lee, Yong-Chul;Kim, Hee-Je
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.335-338
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    • 2007
  • Cost effectiveness is an important parameter for producing DSSCs as compared to the widely used conventional silicon based solar cells. A fluorine-doped tin oxide (FTO) substrate coated with a catalytic amount of platinum is used as counter electrode in dye-sensitized solar cell. Carbonaceous materials are quite attractive to replace platinum due to their high electronic conductivity, corrosion resistance towards $I_{2}$, good catalytic effect and low cost. In this paper, the unit DSSCs with Pt and CNT as a counter electrode were connected in series-parallel externally, then the current-voltage curves were investigated to find out the connection characteristics of the DSSC with CNT counter electrode. The connection characteristics of the DSSC with CNT counter electrode is superior to that of the DSSC with Pt counter electrode. And a parallel connection of the DSSC with CNT counter electrode has higher efficiency than a series connection of that.

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Synthesis and Photo Catalytic Activity of 10 wt%, 20 wt%Li-TiO2 Composite Powders (10 wt%, 20 wt%Li-TiO2 복합분말의 합성과 광촉매 활성평가)

  • Kim, Hyeong-Chul;Han, Jae-Kil
    • Journal of Powder Materials
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    • v.23 no.1
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    • pp.33-37
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    • 2016
  • 10 wt.% and 20 wt.%$Li-TiO_2$ composite powders are synthesized by a sol-gel method using titanium isopropoxide and $Li_2CO_3$ as precursors. The as-received amorphous 10 wt.%$Li-TiO_2$ composite powders crystallize into the anatase-type crystal structure upon calcination at $450^{\circ}C$, which then changes to the rutile phase at $750^{\circ}C$. The asreceived 20 wt%$Li-TiO_2$ composite powders, on the other hand, crystallize into the anatase-type structure. As the calcination temperature increases, the anatase $TiO_2$ phase gets transformed to the $LiTiO_2$ phase. The peaks for the samples obtained after calcination at $900^{\circ}C$ mainly exhibit the $LiTiO_2$ and $Li_2TiO_3$ phases. For a comparison of the photocatalytic activity, 10 wt.% and 20 wt.% $Li-TiO_2$ composite powders calcined at $450^{\circ}C$, $600^{\circ}C$, and $750^{\circ}C$ are used. The 20 wt.%$Li-TiO_2$ composite powders calcined at $600^{\circ}C$ show excellent efficiency for the removal of methylorange.

Degradation of Volatile Hydrocarbons Using Continuous-Flow Photocatalytic Systems with Enhanced Catalytic Surface Areas

  • Jo, Wan-Kuen;Yang, Sung-Hoon;Shin, Seung-Ho;Yang, Sung-Bong
    • Environmental Engineering Research
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    • v.16 no.2
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    • pp.91-96
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    • 2011
  • Limited information is available on the degradation of volatile hydrocarbons determined via the use of plate-inserted photocatalytic reactors. This has led to the evaluation of surface areas of cylindrical continuous-flow photocatalytic reactors for the degradation of three selected aromatic hydrocarbons. Three types of reactors were prepared: a double cylinder-type, a single cylindrical-type without plates and a single cylindrical-type with inserted glass tubes. According to diffuse reflectance, FTIR and X-ray diffraction (XRD) spectroscopy, the surface characteristics of a coated photocatalyst were very similar to those of raw $TiO_2$, thereby suggesting that the coated photocatalyst exhibited the same photocatalytic activity as the raw $TiO_2$. The photocatalytic degradation efficiencies were significantly or slightly higher for the single cylinder-type reactor than for the double cylinder-type reactor which had a greater catalytic surface area. However, for all target compounds, the degradation efficiencies increased gradually when the number of plates was increased. Accordingly, it was suggested that the surface area being enhanced for the plate-inserted reactor would elevate the photocatalytic degradation efficiency effectively. In addition, this study confirmed that both initial concentrations of target compounds and flow rates were important parameters for the photocatalytic removal mechanism of these plate-inserted photocatalytic reactors.

Numerical Analysis on Flow Characteristics in the Reactor of an Integrated Adsorption/Catalysis Process with Bag Filters (백필터를 활용한 흡착/촉매 통합공정 시스템의 반응기 내 유동특성 및 체류시간에 대한 수치해석적 연구)

  • Choi, Choeng-Ryul;Koo, Yoon-Seo
    • Journal of Korean Society for Atmospheric Environment
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    • v.23 no.2
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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.

Hydroxylation of Indole by PikC Cytochrome P450 from Streptomyces venezuelae and Engineering Its Catalytic Activity by Site-Directed Mutagenesis

  • Lee Sang-Kil;Park Je-Won;Park Sung-Ryeol;Ahn Jong-Seog;Choi Cha-Yong;Yoon Yeo-Joon
    • Journal of Microbiology and Biotechnology
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    • v.16 no.6
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    • pp.974-978
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    • 2006
  • The cytochrome P450 monooxygenase from the pikromycin biosynthetic gene cluster in Streptomyces venezuelae, known as PikC, was observed to hydroxylate the unnatural substrate indole to indigo. Furthermore, the site-directed mutagenesis of PikC monooxygenase led to the mutant enzyme F171Q, in which Phe171 was altered to Gln, with enhanced activity for the hydroxylation of indole. From enzyme kinetic studies, F171Q showed an approximately five-fold higher catalytic efficiency compared with the wild-type PikC. Therefore, these results demonstrate the promising application of P450s originating from Streptomyces, normally involved in polyketide biosynthesis, to generate a diverse array of other industrially useful compounds.

Flow Characteristics with Inflow-Duct Types in the Reactor of an Integrated Adsorption/Catalysis Process with Bag Filters (연소 배출가스의 유입방식에 따른 백필터를 활용한 흡착/촉매 통합공정 시스템 반응기 내 유동특성)

  • Choi, Choeng-Ryul
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.5
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    • pp.425-434
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    • 2007
  • An integrated adsorption/catalytic process has been considered to treat dioxin and $NO_x$ simultaneously. The process consists of a cyclone and a reactor with nine bag filters. In this study, numerical analysis has been performed to understand flow characteristics with inflow-duct types in the reactor. To consider flue gas and activated carbon particles simultaneously, Euler-Lagrangian model was employed. Fundamental flow patterns of flue gas and activated carbon particles, pressure distribution and distribution of activated carbon have been obtained from the numerical analysis. Also trace length and residence time of flue gas, residence time of activated carbon particles have been calculated directly. 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 flow characteristics in the reactor were strongly influenced by inflow-duct types. 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.

Effect of Scale and Geometry on the Performance of Heat-Recirculating Swiss roll combustors for Micro Power Generation Applications (마이크로 동력발생용 소형 스위스롤 연소기의 크기와 형상 효과에 대한 연구)

  • Oh, Hwa-Young;Huh, Hwan-Il;Ronney, Paul D.
    • Journal of the Korean Society of Propulsion Engineers
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    • v.15 no.1
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    • pp.1-10
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    • 2011
  • Combustion and extinction limits in heat-recirculating excess enthalpy reactors employing both gas-phase and catalytic reaction have been examined with an emphasis Reynolds number (Re) effects and possible application to microscale combustion devices. In this paper, geometrically similar reactors of different physical sizes and different numbers of turns were tested with the aim of estimating for combustor characteristics. Combustion efficiency is estimated by measuring exhausted gases through the gas chromatograph. From these results the effect of scale and number of turns are demonstrated and optimal operating conditions for Swiss roll combustors are identified.