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RISS 인기검색어
- 검색키워드
- 저자 : Yukun Qin (검색결과 6 건)
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Kinetic modeling of non-hydrocarbon/nitric oxide interactions in a flow reactor above 1,400K
Shaozeng Sun,Zhiqiang Wang,Lin Qian,Yukun Qin,Huali Cao 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.3
The reduction of nitric oxide by reaction with non-hydrocarbon fuels under reducing conditions at comparatively higher temperature has been studied with a detailed chemical kinetic model. The reaction mechanism consists of 337 elementary reactions between 65 chemical species based on the newest rate coefficients. The experimental data were adopted from previous work. Analyses by comparing existing experimental data with the modeling predictions of this kinetic mechanism indicate that, at comparatively high temperature, apart from the reaction path NO→ HNO→NH→N2, NO+N→N2 is also prominent. In the presence of CO, NO is partly converted to N by reaction with CO. Based on present model, the reduction of NO at high temperature, which was usually underestimated by previous work, can be improved to some extent.
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Mechanism of SO_2 adsorption and desorption on commercial activated coke
Fei Sun,,Jihui Gao,Yuwen Zhu,,Yukun Qin 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.11
We used commercial activated coke (AC) as adsorbent and fixed-bed, FTIR, N_2 adsorption, ion chromatograph as research methods to study the SO2 removal mechanism in the presence of O_2 and H_2O and adsorbate (H_2SO_4)desorption mechanism by combined regeneration. The results showed that AC saturation sulfur retention (52.6 mg/g)in SO_2+O_2+H_2O atmosphere was 4.6 times as much as that (11.4mg/g) in SO_2+O_2 atmosphere and 5.0 times as much as that (10.6 mg/g) in SO_2+O_2 atmosphere at 90 ℃. O-2 and H_2O were necessary in AC desulfurization process. Reaction of SO_3 and H-2O (g) and condensation of sulfuric acid vapor were the dynamic of AC desulfurization process. Water vapor blowing in combined regeneration inhibited the reaction between H_2SO_4 and carbon, and consequently reduced the chemical lost of carbon. AC cumulative quality loss (53.6%) of five-times in C-R was still less than that (62.4%)of three-times in H-R. Water vapor blowing inhibited reactivation effect, as a result reducing the changes of AC pore structure and surface functional groups. Adsorbate H_2SO_4 generated in desulfurization evaporated to sulfuric acid vapor due to the high temperature in regeneration and was carried out by water vapor.
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Yuwen Zhu,Jihui Gao,Fei Sun,Yukun Qin 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.12
Taixi anthracite was used as a precursor to prepare activated carbons (AC) for SO_2 adsorption from flue gas. In this work the activated carbons were prepared by physical activation with steam. Specifically, the effects of activation temperature and burn-off degree on the physico-chemical properties of the resulting AC samples were comparatively studied. The different types of pore volumes, pore size distributions and surface chemistries of the activated carbons on the SO_2 adsorption were also analyzed. The results show that the increasing burn-off leads to samples with continuous evolution of all types of pores except ultramicropore. The ultramicropore volume increases to a maximum of 0.169 cm^3/g at around 50% burn-off and then decreases for 850℃ activation. At higher activation temperature, the micropore volume decreases and the mesopore structure develops to a certain extent. For all the resulting AC samples,the quantities of the basic surface sites always appear much higher than the amount of the acidic sites. The activated carbon prepared with higher micropore volume, smaller median pore diameter and higher quantities of the basic surface sites represents better SO_2 sorption property.
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Kinetic analysis of NO-Char reaction
Shaozeng Sun,Xidong Hu,Penghua Qiu,Juan Qian,Yukun Qin,Juwei Zhang 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.2
Two Chinese coals were used to prepare chars in a flat flame flow reactor which can simulate the temperature and gas composition of a real pulverized coal combustion environment. Acid treatment on the YB and SH chars was applied to obtain demineralized chars. Kinetic characterization of NO-char reaction was performed by isothermal thermogravimetry in the temperature range of 973-1,573 K. Presence of catalytic metal matter can increase the reactivity of chars with NO, which indicates that the catalytic effects of inherent mineral matter play a significant role in the NO-char reaction. The discrete random pore model was applied to describe the NO-char reactions and obtain the intrinsic kinetics. The model can predict the data for all the chars at various temperatures well, but underestimate the reaction rates at high carbon conversions for the raw YB and SH chars, which can be attributed to the accumulation of metal catalyst on char surface.
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Enhancement mechanism of SO2 removal with calcium hydroxide in the presence of NO2
Jihui Gao,Guoqing Chen,Xiaolin Fu,Yijun Yin,Shaohua Wu,Yukun Qin 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.2
The enhancement mechanism of SO2 removal by the presence of NO2 under low temperature and humid conditions was studied in a fixed bed reactor system. The presence of NO2 in the flue gas can enhance SO2 removal. The interaction between SO2 and NO2 in gas phase could not explain the effect of NO2 on SO2 removal under lowtemperature and humid conditions. When Ca(NO3)2 and Ca(NO2)2 as additive were added on the surface of sorbent,the desulfurization activity of sorbent decreased. However, the sorbent pretreated by NO2 for a moment has higher SO2removal. The oxidization of SO32− to SO42− and the evolution of sorbent surface structure in the presence of NO2 can explain the enhancement of SO2 removal by the presence of NO2. HSO3− and SO3− reacted with NO2 to form sulfate,which can accelerate the hydrolysis of SO2. The reaction between NO2 and Ca(OH)2 can make the unreacted sorbet under the SO2 removal product exposed to the reactant gas.
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Juncong Sai,Shaohua Wu,Rui Xu,Rui Sun,Yan Zhao,Yukun Qin 한국화학공학회 2007 Korean Journal of Chemical Engineering Vol.24 No.3
the present study, a series of wet flue gas desulfurization experiments have been carried out in com-parison with diferent slurry feeding ways, i.e., by series connection and by parallel connection, by means of cross-flow scrubbing with faling film. The experiment results show that there is optimal desulfurization performance forfer by cross-flow scrubbing model have been developed. The pH values of the outlet slurry inside the reactor and theion concentration distributions of H2SO3, HSO3 and SO32 along the axial direction of the tubes were obtained by an-alyzing and calculating the models. The calculation values agree well with the experimental values. It shows that themodels can predict well the ion concentration distributions along the axial direction of the tubes.
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