内置螺旋挡板流化床颗粒停留时间分布的实验研究

论文总字数：21985字

摘 要

在一有机玻璃制成的内置螺旋挡板流化床内，以玻璃微珠为床料，采用脉冲示踪法进行冷态实验，研究固体颗粒在流化床内的停留时间分布。对于均匀颗粒，进行加料速率、流化风速、颗粒粒径对颗粒在内置螺旋挡板流化床内停留时间分布影响的实验研究；对于含有大颗粒的二元混合颗粒，研究分析流化风速、颗粒大小形状对大颗粒在内置螺旋挡板流化床内停留时间分布的影响。对均匀颗粒，实验发现，随着流化风速增大，固体颗粒的停留时间分布更发散，停留时间变长；颗粒粒径的改变，对固体颗粒停留时间分布的时间跨度基本无影响；加料速率改变，固体颗粒的整体流动速率随之改变，一定速度范围内，加料速率增大，颗粒的迁移速率增大，颗粒在流化床内的停留时间分布变短。对于大颗粒，研究表明，流化风速小时，大颗粒的停留时间短，分布较集中，随流化风速增大，大颗粒的停留时间分布增长。对于小米和芝麻两种不同的大颗粒，形状大小不同，颗粒的停留时间分布也不同。关键词： 内置螺旋挡板流化床，均匀颗粒，大颗粒，颗粒停留时间分布

Abstract

The residence time distribution of the solid particles in a fluidized bed was studied by using a pulsed tracer method in the fluidized bed with a built-in spiral baffle made of plexiglass. The effects of feeding rate, flow rate, particle size on the residence time distribution of the particles in the fluidized bed wthe built - in spiral baffle were studied. For the binary particles with large particles, the effects of fluidized wind speed and particle size on the residence time distribution of the large particles in the fluidized bed with the built-in spiral baffle were studied. The results show that the residence time of the solid particles is more divergent and the residence time becomes longer as the fluidization wind speed increases, and the change of the particle size has no effect on the time span of the residence time of the solid particles. The overall flow rate of the solid particles changes, and the rate of increase of the feed rate increases and the migration rate of the particles becomes shorter in the fluidized bed within a certain speed range. For large particles, the results show that when the fluidization wind speed is small, the residence time of large particles is short and the distribution is concentrated. With the increase of fluidized wind speed, the residence time distribution of large particles increases. For millet and sesame two different large particles, the shape of different sizes, the particle residence time distribution is also different.

KEY WORDS: built-in spiral baffle fluidized bed, uniform particles, large particles, particle residence time distribution

目 录

摘要 ……………………………………………………………………………………………Ⅰ

Abstract …………………………………………………………………………………… Ⅱ

第一章 绪论 1

1.1课题背景及研究意义 1

1.2国内外研究现状 2

1.2.1均匀颗粒在流化床中停留时间分布（RTD）的实验研究 2

1.2.2大颗粒在流化床中停留时间分布（RTD）的实验研究 3

1.2.3有内构件的流化床中颗粒停留时间分布（RTD）的实验研究 3

1.3研究内容与研究目标 4

1.4本章小结 4

第二章 实验系统与实验方法 5

2.1实验系统 5

2.1.1内置螺旋挡板流化床中固体颗粒停留时间测量方法 7

2.1.2数据处理方法 7

2.2实验步骤 8

2.3临界流化风速的测定 9

2.4实验可能遇到的问题以及解决方案 10

2.5本章小结 10

第三章 均匀颗粒停留时间分布（RTD）的实验研究 11

3.1实验材料物性 11

3.2均匀颗粒在流化床中停留时间分布（RTD）的实验结果 12

3.2.1加料速率对停留时间分布的影响 12

3.2.2流化风速对停留时间分布的影响 13

3.2.3床料颗粒大小对停留时间分布的影响 14

3.3本章小结 15

第四章 大颗粒停留时间分布（RTD）的实验研究 16

4.1对大颗粒停留时间分布研究的必要性 16

4.2大颗粒停留时间分布的实验结果与分析 16

4.3本章小结 19

第五章 结论与展望 20

参考文献 22

致 谢 23

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