• Title/Summary/Keyword: Nitrogen dilution

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Experimental detemination of Half-Saturation Coefficient for Nitrifying Bacteria by Infinite Dilution Method (무한희석법(無限稀釋法)을 이용한 질산화(窒酸化) 미생물(微生物) 반포화계수(半飽和係數) 결정(決定)에 관한 실험적(實驗的) 연구(硏究))

  • Lee, Byong-Hee
    • Journal of Korean Society of Water and Wastewater
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    • v.12 no.1
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    • pp.62-69
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    • 1998
  • To remove nitrogen from wastewater, ammonia nitrogen has to be oxidized to nitrate nitrogen before denitrification reaction which converts nitrate nitrogen to nitrogen gas. In order to understand nitrification, several mathematical models had been proposed and Monod type model has been accepted internationally. Since Monod type model consists of maximum substrate utilization rate, substrate concentration and half-saturation coefficient, these values have to be addressed before using Monod type model. Several experimental procedures to determine half-saturation coefficient have been developed, however, Infinite dilution method was known to be time saving procedure. In this study, the mathematical equations and experimantal procedures for Infinite dilution method are presented and this method is used to determine half-Saturation coefficient for nitrifying bacteria. As results, Infinite dilution method is proved that this coefficient can be determined within 8 hours and the values of half-saturation coefficient has a range of 0.728 and $0.455gNH_4{^+}-N/m^3$ and the average has $0.580gNH_4{^+}-N/m^3$ through 5 sets of experiments.

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Analysis of the Effects of Fuel-side Nitrogen Dilution and Pressure on NOx Formation of Turbulent Syngas Nonpremixed Jet Flame (질소희석과 압력이 석탄가스 난류 확산화염장의 NOx 생성특성에 미치는 영향 해석)

  • Park, Sangwoon;Lee, Jeongwon;Kim, Yongmo
    • 한국연소학회:학술대회논문집
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    • 2012.11a
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    • pp.63-64
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    • 2012
  • The present study has numerically investigated the effects of the fuel-side nitrogen dilution on the precise structure and NOx formation characteristics of the turbulent syngas nonpremixed flames. Numerical results indicate that for highly diluted case, the flame structure is dominantly influenced by the turbulence-chemistry interaction and marginally modified by the radiation effect. On the other hand, no-dilution case with the longer flight time and the relatively intermediate scalar dissipation rate is influenced strongly by the radiative cooling as well as moderately by the turbulence-chemistry interaction.

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Removal of Inorganic Nitrogen and Phosphorus from Cow s Liquid Manure by Batch Algal Culture

  • KIM, MAM-SOO;MOO-YOUNG PACK
    • Journal of Microbiology and Biotechnology
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    • v.3 no.3
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    • pp.214-216
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    • 1993
  • Cow's liquid manure (CLM), an animal waste, was treated by a batch algal culture to remove inorganic nutrients. CLM used in this study was especially high in concentrations of inorganic nitrogen and phosphorus. The optimum dilution ratio of the CLM for maximum algal growth was 1:25. Ninety five percent of inorganic nitrogen and 100% of inorganic phosphorus were removed from the CLM with a dilution ratio of 1:25.

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Fuel Dilution Effects for Stratified Premixed Flames (성층화된 예혼합화염에 대한 희석제 첨가의 영향)

  • Ahn, Taekook;Lee, Wonnam
    • 한국연소학회:학술대회논문집
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    • 2013.06a
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    • pp.73-76
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    • 2013
  • The inert gas dilution effect for the stability of a stratified propane premixed flame has been experimentally studied. The addition of inert gases to a stratified premixed flame, which used to be very stable without dilution, makes a flame unstable. The lower equivalence ratio on the outer premixed flame and the lower fuel flow rate through the inner nozzle were observed to be the more stable conditions for the stratified premixed flame with nitrogen or argon dilution. It has been interpreted with the flame structure change such as shift of stoichiometric ratio region in a flame.

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Soot Formation in a Double-Concentric Diffusion Flame (동축 이중 확산화염의 매연 생성 특성)

  • Jurng, Jongsoo;Lee, Gyo-Woo;Ko, Bum-Seung;Kang, Kyung-tae
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.11
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    • pp.1355-1362
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    • 1999
  • An experimental study on a double-concentric diffusion flame(DDF) has been carried on in order to Investigate the characteristics of soot formation compared to a normal coflow diffusion flame(NDF). Laser extinction technique has been used for an ethylene($C_2H_4$) and air flame with various flow rates. Soot formation In the double-concentric diffusion flame was enhanced by the inner inverse diffusion flame due to the increase in flame temperature and also suppressed due to the nitrogen-dilution from the inner air. Soot concentration at the flame axis of DDF was higher than that of the NDF, mainly because of the increase of temperature by inner flame. However, the maximum soot volume fraction of DDF was lower than NDF at the outer side of the flame, mainly due to the effect of nitrogen-dilution from the inner air.

Determination of Critical Nitrogen Concentration and Dilution Curve for Rice Growth

  • Lee, Byun-Woo;Cui, Ri-Xian;Kim, Min-Ho;Kim, Jun-Hwan;Nam, Hong-Shik
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.47 no.2
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    • pp.127-131
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    • 2002
  • Critical nitrogen concentration (Nc), which is defined as the minimum % N in shoots required to maintain the maximum growth rate of top dry weight (W) at any time, was determined for rice plant. Using two rice varietal groups, japonica varieties and an indica $\times$ japonica "Dasanbyeo", 18 data points fulfilling the statistical criteria for determining Nc were obtained through eight N-fertilization experiments over two years at Suwon (37$^{\circ}$16'N), Korea. Nc dilution curve for each variety was obtained by fitting the Nc-W relationship to power function. However, The critical nitrogen curves for the two variety groups were not different statistically. Thus, a Nc dilution curve was fitted for the Nc data points pooled over the two variety groups and proposed in rice as: Nc=4.08, where W<1.73 t h $a^{-1}$ , Nc=5.197 $W^{0.425}$3/ ($R^2$=0.964), where 1.73 t h $a^{-1}$ <W<12 t h $a^{-l}$. The Nc for W<1.73 t h $a^{-l}$ were estimated as a constant value of 4.08%, the mean value of the maximum N concentration for N-limiting condition and the minimum N concentration for N non-limiting condition. The model for Nc is applicable to diagnosing the nitrogen nutrition status during the rice growth period from emergence to heading stage. The Nc curve well discriminated the 144 data points between the N limiting and the N non-limiting groups regardless of varieties, cultural methods, and years.-limiting groups regardless of varieties, cultural methods, and years.

The Effect of N2 Dilution on the Flame Stabilization in a Non-Premixed Turbulent H2 Jet with Coaxial Air (질소 희석이 수소 난류확산화염의 화염안정성에 미치는 영향)

  • Oh, Jeong-Seog;Yoon, Young-Bin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.7
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    • pp.477-485
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    • 2009
  • The study of nitrogen dilution effect on the flame stability was experimentally investigated in a non-premixed turbulent lifted hydrogen jet with coaxial air. Hydrogen gas was used as a fuel and coaxial air was used to make flame liftoff. Each of hydrogen and air were injected through axisymetric inner and outer nozzles ($d_F=3.65\;mm$ and $d_A=14.1\;mm$). And both fuel jet and coaxial air velocity were fixed as $u_F=200\;m/s$ and $u_A=16\;m/s$, while the mole fraction of nitrogen diluents gas was varied from 0.0 to 0.2 with 0.1 step. For the analysis of flame structure and the flame stabilization mechanism, the simultaneous measurement of PIV/OH PLIF laser diagnostics had been performed. The stabilization point was selected in the most upstream region of the flame base and defined as the point where the turbulent flame propagation velocity was equal to the axial component of local flow velocity. We found that the turbulent flame propagation velocity increased with the decrease of nitrogen mole fraction. We concluded that the turbulent flame propagation velocity was expressed as a function of turbulent intensity and axial strain rate, even though nitrogen diluents mole fraction was changed.

Effects of Fuel-Side dilution and Pressure on Structure and Extinction Scalar Dissipation Rate of Syngas Nonpremixed Flames (질소희석과 압력이 석탄가스 비예혼합 화염구조와 소염 스칼라 소산율에 미치는 영향 해석)

  • Park, Sangwoon;Shin, Youngjun;Kim, Yongmo
    • 한국연소학회:학술대회논문집
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    • 2012.11a
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    • pp.61-62
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    • 2012
  • The present study has numerically investigated the effects of fuel-side dilution and pressure on flame structure and extinction scalar dissipation rate of turbulent syngas nonpremixedd flames. Numerical results indicate that for highly diluted case, peak temperature is decreased and stoichiometric mixture fraction is increased. By decreasing the pressure and the nitrgen dilution levelcreased, the extinction scalar dissipation rate is increased.

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Performance Analysis of IGCC Gas Turbine Considering Turbine Operation Condition Change due to Modulation of Nitrogen Dilution (질소희석량 조절에 따른 터빈 운전조건 변화를 고려한 IGCC 용 가스터빈의 성능분석)

  • Kim, Chang Min;Kang, Do Won;Kim, Tong Seop
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.11
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    • pp.1023-1029
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    • 2013
  • The integration between a gas turbine and an air separation unit (ASU) is important in IGCC plants. The portion of ASU air extracted from the gas turbine and the degree of nitrogen supply from the ASU to the gas turbine side are important operating parameters. Their effect on the gas turbine performance and operability should be considered in a wide ambient temperature range. In this study, appropriate nitrogen dilution rate and turbine inlet temperature that satisfy the two limitations of turbine blade temperature and maximum allowable power output were predicted. The air integration was set at zero. The simulation showed that the power output increases and turbine blade temperature decreases as the nitrogen dilution increases. The maximum allowable power output can be obtained under medium and low ambient temperature ranges. Under a high ambient temperature range, the achievable power is less than the maximum power.

Analysis on the Performance and the Emission of the Integrated Gasification Combined Cycle Using Heavy Oil (중잔사유 가스화 복합발전 사이클의 성능 및 환경배출 해석)

  • Lee, Chan;Yun, Yong-Seong
    • Journal of Energy Engineering
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    • v.10 no.3
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    • pp.188-194
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    • 2001
  • The process simulations are made on the IGCC power plant using heavy residue oil from refinery process. In order to model combined power block of IGCC, the present study employs the gas turbine of MS7001FA model integrated with ASU (Air Separation Unit), and considers the air extraction from gas turbine and the combustor dilution by returned nitrogen from ASU. The exhaust gas energy of gas turbine is recovered through the bottoming cycle with triple pressure HRSG (Heat Recovery Steam Generator). Clean syngas fuel of the gas turbine is assumed to be produced through Shell gasification of Visbreaker residue oil and Sulfinol-SCOT-Claus gas cleanup processes. The process optimization results show that the best efficiency of IGCC plant is achieved at 20% air extraction condition in the case without nitrogen dilution of gas turbine combustor find at the 40% with nitrogen dilution. Nitrogen dilution of combustor has very favorable and remarkable effect in reducing NOx emission level, while shifting the operation point of gas turbine to near surge point.

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