加压循环流化床冷态试验研究

发布时间：2018-05-12 13:08

本文选题：加压循环流化床 + 关键部件　；参考：《中国科学院大学(中国科学院工程热物理研究所)》2017年硕士论文

【摘要】：在促进能源高效利用的背景下,加压煤气化技术缩小了设备尺寸、减少了压缩能耗,是煤气化技术降低设备成本、运行成本和实现大型化必由之路。加压条件下,提升管内的气固流动特性和循环过程较常压下更为复杂,通过试验研究掌握加压条件下循环流化床的运行规律,可为加压气化工程示范项目的设计和运行提供理论依据。然而,现阶段关于加压循环流化床的研究相对较少,所以需要进一步深入研究。针对研究内容,建设了一个加压循环流化床冷态试验台,提升管直径为300mm,有效高度为8700mm,设计了不同的关键部件(返料器、提升管上部变径段、提升管顶部凸头)结构进行试验研究,物料采用平均粒径为0.347mm、堆积密度为1435kg/m3的石英砂。试验台调试结束后,开展了不同操作参数(压力、表观气速、物料量)、不同关键部件结构参数对提升管内气固流动特性影响的试验研究。研究结果表明:在加压条件下,提升管内的表观颗粒体积分数呈上小下大的分布规律,随物料量的增大而增大,随表观气速的增加逐渐趋于均匀;在物料量和表观气速一定的情况下,增加压力可以显著提高提升管上部的表观颗粒体积分数,在0.5MPa压力下变化较为明显。采用Φ150mm和Φ200mm返料器均可建立正常的物料循环,改变返料器的直径并未改变提升管内的表观颗粒体积分数分布,采用Φ150mm返料器要优于Φ200mm返料器,且在阻力不太大的情况下,适当提高返料器的隔板高度可以建立较好的物料循环;提升管顶部采用凸头结构可以增大提升管顶部的表观颗粒体积分数;在循环流率相近的情况下,采用新型返料器可以提供相对较高的逆压差,最高可达5.47kPa。
[Abstract]:Under the background of promoting the efficient utilization of energy, pressurized coal gasification technology reduces the size of equipment and reduces the energy consumption of compression, which is the only way for coal gasification technology to reduce the cost of equipment, run cost and realize large-scale gasification. Under the pressure condition, the gas-solid flow characteristics and the circulation process in the riser are more complicated than under the normal pressure. The operation law of the circulating fluidized bed under the pressure condition is grasped through the experimental study. It can provide the theoretical basis for the design and operation of the demonstration project of pressurized gasification project. However, there is relatively little research on pressurized circulating fluidized bed at present, so further research is needed. In view of the research content, a cold test bed of pressurized circulating fluidized bed is built. The diameter of the riser is 300mm and the effective height is 8700mm. Different key components are designed. The material was made of quartz sand with average particle size of 0.347mm and packing density of 1435kg/m3. After the test rig was finished, the effects of different operating parameters (pressure, apparent gas velocity, material quantity, structure parameters of different key components) on the gas-solid flow characteristics in the riser were studied. The results show that under the pressure condition, the apparent particle volume fraction in the riser is larger than that in the upper one, which increases with the increase of the material content, and tends to be uniform with the increase of the apparent gas velocity. Under the condition of constant material volume and apparent gas velocity, the apparent particle volume fraction in the upper part of the riser can be significantly increased by increasing the pressure, and the change is obvious under the pressure of 0.5MPa. Normal material circulation can be established by using 桅 150mm and 桅 200mm feeders. The diameter of the feeders does not change the apparent particle volume fraction distribution in the riser. The 桅 150mm feeders are superior to 桅 200mm feeders, and when the resistance is not too large, the volume fraction distribution of the apparent particles in the riser is not changed. A better material circulation can be established by raising the height of the separator properly, the apparent particle volume fraction at the top of the riser can be increased by using a convex head structure at the top of the riser, and when the circulation rate is similar, the volume fraction of the apparent particle at the top of the riser can be increased. A relatively high inverse pressure difference can be provided by using a new backfeed device, with a maximum of 5.47 KPA.
【学位授予单位】：中国科学院大学(中国科学院工程热物理研究所)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ051.13

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