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循环流化床内颗粒运动特性 总被引:2,自引:0,他引:2
1前言循环流化床作为一种先进的清洁煤燃烧技术,尤其在脱硫方面具有的独特优越性,使其在电力行业发展迅速。单台容量为250MWe级的循环流化床电站锅炉预计将在1998年运行,同时,国外正着手利用循环流化床燃烧技术改造老式煤粉锅炉。尽管循环流化床技术在工业界取得了很快的发展,但作为技术核心的内部颗粒运动特性还需做进一步的研究,以便为模型计算和装置放大提供更为精确的微观颗粒运动数据。作者为了探求循环床内颗粒运动特性,以求得到对工业发展的有用规律、优化设计及运行操作,利用FFT技术对三千多组颗粒浓度、颗粒速度和颗粒动… 相似文献
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采用XANES和XPS解析山西炼焦煤中有机硫的赋存特征,选择与煤中结构匹配的噻吩硫模型化合物进行微波辐射和水浴加热,通过Raman光谱比较研究两者对模型化合物中含硫结构的作用机制,利用Materials Studio构建、优化模型化合物结构,用密度泛函理论计算模拟微波场中模型化合物分子构型参数,解析含硫结构对微波的响应机理。结果表明:噻吩硫是炼焦煤中有机硫最主要的赋存形式。微波辐射后,模型化合物碳硫键和硫硫键的Raman谱吸收峰发生红移,温升速度快的模型化合物红移较小;相同温升的水浴加热后,几乎没有红移现象。微波能量不足以使模型化合物中碳硫键和硫硫键断裂,但能够改变分子构型,模型化合物含硫键在微波场中可能存在某种过渡态。微波作用对煤中噻吩硫结构存在非热效应。 相似文献
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为了探究煤中噻吩类有机硫化合物降解规律,采用密度泛函理论搜索过渡态提出了两条反应路径。通过对反应路径中各物种的原子电荷、热力学、动力学参数和噻吩降解的势能剖面图分析得出:各路径发生的难易程度是不同的,噻吩降解的最有利的反应路径为Path1,即首先是H9转移到S5上,接着H8从C3转移到C4上伴随着C4-S5键的断裂,然后H6转移到S5上,最后随着H7从C2转移到C1上,H2S离开原来的结构,丁二炔形成。利用密度泛函理论对煤中噻吩类含硫模型化合物在不同降解路径中的变化规律进行研究,可以有助于理解煤中噻吩硫的脱除机理,为煤中噻吩类有机硫的脱除实验及工业处理过程提供理论指导。 相似文献
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Qiong Tang Song Lin Ying Cheng Sujun Liu Jun-Ru Xiong 《Ultrasonics sonochemistry》2013,20(5):1168-1175
This work investigated the ultrasonic assisted oxidative desulfurization of bunker-C oil with TBHP/MoO3 system. The operational parameters for the desulfurization procedure such as ultrasonic irradiation time, ultrasonic wave amplitude, catalyst initial concentration and oxidation agent initial concentration were studied. The experimental results show that the present oxidation system was very efficient for the desulfurization of bunker-C oil and ~35% sulfur was removed which was dependent on operational parameters. The application of ultrasonic irradiation allowed sulfur removal in a shorter time. The stronger the solvent polarity is, the higher the sulfur removal rate, but the recovery rate of oil is lower. The sulfur compounds in bunker-C oil reacted with TBHP to produce corresponding sulfoxide, and further oxidation produced the corresponding sulfone. 相似文献
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Sulfur-doped ZnO particles have been synthesized by hydrothermal method. The structural and optical properties were studied systematically by XRD, scanning electron microscopy (SEM), and photoluminescence. SEM results show that the particle is hexagonal and the average size decreases with increasing sulfur doping, which means a retardant effect of sulfur on the growth of S-doped ZnO. XRD results show that the lattice parameters increase with more sulfur, which means an effective sulfur doping and increasing strain. Optical characterization also shows that the effective sulfur doping will enhance the green emission and suppress the near bandgap emissions. 相似文献
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I. N. Sergeev V. K. Kumykov V. A. Sozaev M. A. Shebzukhova 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(10):1388-1390
The competitive segregation of sulfur, carbon, and phosphorus on the surface of polycrystalline copper and the segregation kinetics of sulfur in the temperature range 675–875 K have been investigated by Auger electron spectroscopy. The equilibrium segregation energies of impurities and the sulfur diffusion parameters in the near-surface region of copper with a thickness d ≤ 5 μm have been calculated on the basis of the experimental data. 相似文献
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Masato Osumi Takeshi Kunitomo 《Journal of Quantitative Spectroscopy & Radiative Transfer》1979,21(3):243-248
This paper presents the calculated results for line-shape parameters in the v1 and v3 bands of sulfur dioxide for temperatures between 300 and 1200°K, together with the self-broadening coefficients for some particular rotational lines. The Anderson-Tsao-Curnutte theory was applied to calculate the line half-widths, and a criterion was introduced to determine the line-shape parameters on the basis of a narrow-band model. The calculated results are greatly different from previously assumed values. 相似文献
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The adsorption of the model sulfur compound dibenzothiophene (DBT) from n-octane solution on to bamboo charcoal (BC) was investigated. The equilibrium and kinetics of DBT adsorption on BC were examined. Adsorption isotherm of DBT on BC was determined and correlated with two well-known isotherm equations (Langmuir and Freundlich). The equilibrium data for DBT adsorption fitted the Freundlich model well. Two simplified kinetic models including pseudo first-order and pseudo second-order equations were selected to follow the adsorption processes. The adsorption of DBT on BC can be best described by a pseudo second-order equation. The parameters of this best-fit kinetic model were calculated and discussed. 相似文献
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针对亚法糖厂澄清工段清汁色值和清汁残硫量难以在线测量的问题,提出了一种基于人工蜂群优化的在线极限学习机软测量方法。先用核主元分析法确定影响清汁质量的关键参数,建立基于在线极限学习机的软测量模型。同时利用人工蜂群算法对在线极限学习机的隐层参数进行寻优,优化所建模型。最后,使用带约束的粒子群对软测量模型进行优化求解,得到典型工况下的最优操作设定值,为后续工况操作提供参考依据。仿真结果表明,基于人工蜂群优化的在线极限学习机模型能够准确地预测清汁色值和残硫量,同时基于此模型优化的操作参数设定值能够达到期望的指标。 相似文献
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利用Tang-Toennies势模型(以下简称TT势),计算了(Ne、Ar、Kr、Xe)-SF6相互作用势,在此基础上得到了SF6在惰性气体中的扩散系数,粘滞系数和热传导系数,通过相互作用势与M3SV势比较及输运性质与实验值的比较,说明了TT势模型是一种简单、可靠的势模型。 相似文献
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High-concentration H2S formed in the reduction zone of pulverized coal air-staged combustion can result into the high temperature corrosion of water wall tube of boiler, so it is of great importance to accurately predict H2S concentration for the safe operation of boilers and burners. H2S formation and evolution depends on two steps: the sulfur release from coal conversion and gas-phase reactions of sulfur species. In this study, the sulfur release characteristics from the pyrolysis of 17 coals, including 5 lignite, 9 bituminous coals and 3 anthracites, are investigated in a drop tube furnace (DTF). Sulfur release model is developed to describe the relationship between sulfur release and coal types. A global gas-phase reaction mechanism of sulfur species composed of ten reactions is used to calculate and predict the formation and evolution of H2S, COS and SO2 in the reduction zone of pulverized coal air-staged combustion. A wide range of air-staged combustion experiments of 17 coals are conducted in the DTF at different temperatures and stoichiometric ratios to validate the developed model. The results show that the prediction errors of sulfur species, including SO2, H2S and COS, are within ± 30%, which indicates that the developed prediction model of sulfur species is of great assistance for CFD modeling of actual engineering application. 相似文献