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Computational Simulation for Local Reactions in a Fluidized Bed Grid Zone

流化床网格区域局部反应的计算模拟

基本信息

批准号：
02650699
负责人：
KOJIMA Toshinori
金额：
$ 0.45万
依托单位：
Department of Industrial Chemistry, Seikei University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02650699/
关键词：
fluidized bed simulation grid zone modeling cold model chemical vapor deposition polycrystalline silicon coal gasification トレ-サ-ガスガス濃度分布

项目摘要

A cold model experiment and development of a fluidized bed grid zone modelLocal behavior of gas and sohds in a grid zone was investigated by using a fluidized bed cold model. A couple of optical fiber sensors were used to measure a local particle velocity, its concentration, jet diameter and jet height. Local tracer gas concentration was measured by using a gas sampling prove and a gas chromatograph. Circulation of sohds and gas was found to be better when a cone-shaped distributor was employed than that when a flat distributor was used. A numerical model of a fluidized bed grid zone was developed for the description of the cold model data. The numerical results on concentration profiles of gas in the grid zone and particle velocity in jet well coincided with the experimental cold model data when flat distributor was employed. However, when a cone-shaped gas injecter was employed, the numerical results showed lower extent of mixing of gas and solids then those observed experimentally. It was suggest that more complex mixing of gas and solids was occurred in the later case.Applications of the grid zone modelThe grid zone model was applied to chemical vapor deposition of polycrystaflffie silicon by monosilane pyrolysis. The numerical results suggested that the fines mainly tonned in bubbles. The numerical model well expected the experimentally observed effects of gas velocity, bed temperature, silane concentration and grid structure on the likelihood of clogging. A model combining a fluidized bed grid zone model and Kunii-Levenspiel bubbling bed model was proposed and was applied to the analysis of the local progress of coal gasification. From the comparison of the numerical and experimental results, the contribution of the reaction in the grid zone was found to be significant to the overail reactions. Further study on the steam and CO_2 gasification kinetics was found to be necessary.

沸腾床格区冷态模型的试验与发展利用沸腾床冷态模型研究了栅格区内气体和固体的局部行为。使用几个光纤传感器测量了局部颗粒速度、浓度、射流直径和射流高度。用气体取样器和气相色谱仪测量了局部示踪气体浓度。采用锥形布料器时，固体和气体的循环情况要好于采用平面布料器时。为了描述冷态模型数据，建立了一个沸腾床格区的数值模型。采用平板分布板时，网格区域气体浓度分布和射流井内颗粒速度的数值结果与冷模实验数据吻合较好。然而，当采用锥形气体喷射器时，数值结果显示气固混合程度比实验观测的要低。网格区模型的应用将网格区模型应用于单硅烷热解化学气相沉积多晶硅的研究。数值结果表明，细粉主要以气泡形式存在。数值模型很好地预测了实验观察到的气速、床温、硅烷浓度和网格结构对堵塞可能性的影响。提出了一种将床格区模型和Kunii-LeverSpiel鼓泡床模型相结合的模型，并将其应用于煤气化局部过程的分析。通过数值计算和实验结果的比较，发现网格区的反应对总反应的贡献是显著的。对水蒸气和二氧化碳气化动力学的进一步研究是必要的。