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首页> 外文学位 >MEASURING AND MODELLING SOLID MIXING AND PARTICLE RESIDENCE TIMES IN A GAS-SOLID FLUIDIZED BED REACTOR FOR BIOMASS FLASH PYROLYSIS.
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MEASURING AND MODELLING SOLID MIXING AND PARTICLE RESIDENCE TIMES IN A GAS-SOLID FLUIDIZED BED REACTOR FOR BIOMASS FLASH PYROLYSIS.

机译：气固流化床气化流化床反应器中固相混合和颗粒停留时间的测量和建模。

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摘要

The purpose of this study was to simulate the behaviour of a relatively large and shallow fluidized bed for biomass flash pyrolysis (Waterloo Pyrolysis Process) with respect to the solid movement pattern and to experimentally measure the radial mixing behaviour of the solids.;Solid particle mixing was described as occurring by a dispersion mechanism. Axial and radial solid dispersion coefficients were experimentally evaluated as functions of operating parameters and local positions within the fluidized bed. A general correlation was derived based on the experimental results, able to predict the extent of solid lateral mixing as a function of most influencial parameters.;A further study was carried out to estimate the residence time distribution of biomass particles injected into the pyrolysis fluidized bed reactor. The experimental results demonstrated that the elutriation of low density particles (simulating the char) is a function of fluidizing velocity, particle size and particle density. Wood particles injected into the unit remained well mixed with the bed material (sand), regardless of the gas velocity used within the normal operating range of the pyrolysis process. Lighter particles simulating the solid pyrolysis product were observed to leave the reactor after a few seconds of residence time, entrained into the gaseous stream. A circulation model was used for interpreting the flow of the light particles through the fluid bed and was demonstrated to be a very realistic model able to predict very closely the real physical mechanism involved in the mixing-elutriation process occurring during the pyrolysis.;Practical charts were subsequently proposed, which are useful in indicating what are the physical characteristics of the particles which can be respectively elutriated from the fluid bed, or well mixed into the vessel.;A 0.27 m diameter fluidized bed reactor was designed. A unique method was developed which allowed the continuous determination of variations in solid tracer concentration with time at different radial and axial positions within the bed.;Solids distribution in a hypothetical large scale fluidized bed reactor was simulated, where solids concentration profiles around multiple feed points were calculated. Finally, design considerations were reviewed. (Abstract shortened with permission of author.)
机译：这项研究的目的是模拟一个相对较大和较浅的流化床，用于生物质闪速热解（滑铁卢热解过程），涉及固体运动模式，并通过实验测量固体的径向混合行为。被描述为通过分散机制发生。根据工作参数和流化床内局部位置的函数，对轴向和径向固体分散系数进行了实验评估。根据实验结果得出一般相关性，可以预测固体横向混合的程度与大多数影响参数的关系。;进行了进一步的研究以估计注入热解流化床的生物质颗粒的停留时间分布反应堆。实验结果表明，低密度颗粒的淘析（模拟炭）是流化速度，粒度和颗粒密度的函数。不管在热解过程的正常操作范围内使用的气体速度如何，注入到装置中的木材颗粒都与床层材料（沙）保持良好的混合。观察到模拟固体热解产物的较轻颗粒在停留几秒钟后离开反应器，被夹带到气流中。循环模型用于解释轻颗粒通过流化床的流动，并被证明是一个非常现实的模型，能够非常精确地预测热解过程中发生的混合淘析过程中涉及的实际物理机制。随后提出了这些建议，这对于指示可以分别从流化床中淘出或充分混合到容器中的颗粒的物理特性是有用的。设计了一个直径为0.27 m的流化床反应器。开发了一种独特的方法，该方法可以连续确定床中径向和轴向位置上固体示踪剂浓度随时间的变化。;模拟了假设的大型流化床反应器中的固体分布，其中多个进料点附近的固体浓度分布被计算。最后，回顾了设计注意事项。 （摘要经作者许可缩短。）

著录项

  • 作者

    BERRUTI, FRANCO.;

  • 作者单位

    University of Waterloo (Canada).;

  • 授予单位 University of Waterloo (Canada).;
  • 学科 Engineering Chemical.
  • 学位 Ph.D.
  • 年度 1986
  • 页码 332p.
  • 总页数 332
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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