• Title/Summary/Keyword: Chemical kinetics

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Study of Soot Formation in Fuel Rich Combustion (농후 연소 추진제의 Soot 생성 특성에 관한 연구)

  • Yu, Jung-Min;Lee, Chang-Jin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.04a
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    • pp.143-147
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    • 2007
  • Kerosene and diesel are compounded fuels with various types of hydrocarbon elements and difficult to model the chemical kinetics. This study focuses on the prediction of the non-equilibrium reaction of fuel-rich combustion with detailed kinetics developed by Dagaut using PSR(perfectly stirred reactor) assumption. In Dagaut's surrogate model for kerosene and diesel, chemical kinetics consists of 2352 reaction steps with 298 chemical species. Also, Frenklach's soot model was implemented along with detailed kinetics to calculate the gas properties of fuel rich combustion efflux.

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Crystallization Kinetics of Reactive Dye(Reactive Red 218) in Salting-out Crystallization System (반응성 염료(Reactive Red 218)의 염석결정화계에서의 결정화 속도)

  • Han, Hyun-Kak;Kang, Hye-jin;Lee, Jong-hoon
    • Korean Chemical Engineering Research
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    • v.48 no.6
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    • pp.712-716
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    • 2010
  • Salting-out technique was adopted to crystallize dye crystals from dye solution. Solubility of dye solution and crystallization kinetics of Reactive Red 218 was investigated. Solubility of dye solution is decreased by higher KCl concentration. The empirical expressions of salting-out crystallization kinetics for Reactive Red 218 in continuous MSMPR crystallizer was $G=6.864{\times}10^{-5}{\Delta}C^{1.207}$ and $B^0=4.8{\times}10^{22}{\Delta}C[1.1{\times}10^{-13}+{({\Delta}C)}^{0.7}{M_T}^2]$.

Dependence of an Interfacial Diels-Alder Reaction Kinetics on the Density of the Immobilized Dienophile: An Example of Phase-Separation

  • Min, Kyoung-Mi;Jung, Deok-Ho;Chae, Su-In;Kwon, Young-Eun
    • Bulletin of the Korean Chemical Society
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    • v.32 no.5
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    • pp.1679-1684
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    • 2011
  • Interfacial reactions kinetics often differ from kinetics of bulk reactions. Here, we describe how the density change of an immobilized reactant influences the kinetics of interfacial reactions. Self-assembled monolayers (SAMs) of alkanethiolates on gold were used as a model interface and the Diels-Alder reaction between immobilized quinones and soluble cyclopentadiene was used as a model reaction. The kinetic behavior was studied using varying concentrations of quinones. An unusual threshold density of quinones (${\Gamma}_c$ = 5.2-7.2%), at which the pseudo-first order rate constant started to vary as the reaction progressed, was observed. This unexpected kinetic behavior was attributed to the phase-separation phenomena of multi-component SAMs. Additional experiments using more phase-separated two-component SAMs supported this explanation by revealing a significant decrease in ${\Gamma}_c$ values. When the background hydroxyl group was replaced with carboxylic or phosphoric acid groups, ${\Gamma}_c$ was observed at below 1%. Also, more phase-separated thermodynamically controlled SAMs produced a lower critical density (3% < ${\Gamma}_c$ < 4.9%) than that of the less phaseseparated kinetically controlled SAMs (6.5% < ${\Gamma}_c$ < 8.9%).

Kinetics of nitrification and acrylamide biodegradation by Enterobacter aerogenes and mixed culture bacteria in sequencing batch reactor wastewater treatment systems

  • Madmanang, Romsan;Jangkorn, Siriprapha;Charoenpanich, Jittima;Sriwiriyarat, Tongchai
    • Environmental Engineering Research
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    • v.24 no.2
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    • pp.309-317
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    • 2019
  • This study evaluated the kinetics of acrylamide (AM) biodegradation by mixed culture bacteria and Enterobacter aerogenes (E. aerogenes) in sequencing batch reactor (SBR) systems with AQUASIM and linear regression. The zero-order, first-order, and Monod kinetic models were used to evaluate the kinetic parameters of both autotrophic and heterotrophic nitrifications and both AM and chemical oxygen demand (COD) removals at different AM concentrations of 100, 200, 300, and 400 mg AM/L. The results revealed that both autotrophic and heterotrophic nitrifications and both AM and COD removals followed the Monod kinetics. High AM loadings resulted in the transformation of Monod kinetics to the first-order reaction for AM and COD removals as the results of the compositions of mixed substrates and the inhibition of the free ammonia nitrogen (FAN). The kinetic parameters indicated that E. aerogenes degraded AM and COD at higher rates than mixed culture bacteria. The FAN from the AM biodegradation increased both heterotrophic and autotrophic nitrification rates at the AM concentrations of 100-300 mg AM/L. At higher AM concentrations, the FAN accumulated in the SBR system inhibited the autotrophic nitrification of mixed culture bacteria. The accumulation of intracellular polyphosphate caused the heterotrophic nitrification of E. aerogenes to follow the first-order approximation.

Modeling of Non-Equilibrium Kinetics of Fuel Rich Combustion in Gas Generator (농후 연소 가스발생기의 비평형 연소 화학반응 모델링)

  • 유정민;이창진
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.7
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    • pp.89-96
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    • 2006
  • The combustion temperature in gas generator should be kept below around 1,000K to avoid any possible thermal damages to turbine blade by adopting either fuel rich or oxidizer rich combustion. Thus, non-equilibrium chemical reaction dominates in the gas generator. Meanwhile, Kerosene is a compounded fuel mixed with various types of hydrocarbon elements and difficult to model the chemical kinetics. This study focus to model the non-equilibrium chemical reaction of kerosene/LOX with detailed kinetics developed by Dagaut using PSR(Perfectly stirred reactor) assumption. Also, droplet evaporation time is taken into account by calculating for the residence time of droplet and by decoupling reaction temperature from the reactor temperature. In Dagaut’s surrogate model for kerosene, chemical kinetics of kerosene consists of 1592 reaction steps with 207 chemical species. The comparison of calculation results with experimental data could provide very reliable and accurate numbers in the prediction of combustion gas temperature, species fraction and other gas properties.