立装填料塔的热模实验研究

发布时间：2018-03-28 00:10

本文选题：立装填料　切入点：流体力学　出处：《西北大学》2015年硕士论文

【摘要】：本文针对填料塔中液相的壁流效应、大范围流体分布不均及径向流动所引起的“放大效应”进行了热模实验研究。在直径800mm工业规模精馏塔内,以乙醇水为物系,在全回流条件下,研究同规格的平装与立装两种装填方式的板波纹填料和金属丝网填料的流体力学性能和传质性能。实验结果显示：同等条件下,立装与平装的板波纹填料相比,每米填料压降平均降低36.52%,单位理论板压降平均降低28.24%,等板高度平均增加18.15%；立装与平装的金属丝网填料相比,每米填料压降、单位理论板压降变化不明显,而等板高度平均增加10.99%。本次设计的立装填料,是将整块的平装填料分割成8个小的传质单元,传质单元之间相互独立,相当于8个小型填料塔。希望借此隔断液体的径向流动,从而解决填料内部流体不均匀分布问题,减弱填料塔的放大效应,提高传质效率。而实验结果显示,两种立装填料与相应平装填料相比,传质效率有所降低,这与我们的预期恰好相反,说明立装填料塔的构思与实际不符。立装填料塔使用了一种新型液体分配器,通过Perry作图法对分配器分布质量进行初步评价,并通过水力学实验对其结果进行验证。结果表明：该分配器分布质量均匀,分配性能良好。同时说明前述实验不存在初始分布不均问题。通过分析立装填料塔内的液体流动分布机理,建立了针对立装填料的壁流数学模型。认为立装填料基本解决了流体径向流动问题,但是分块化的结构导致实际的壁流量有所增加,且初步设计的立装填料没有考虑液体轴向上的重新分配。综上使得液体局部的不均匀分布较为严重,气液接触状况较差,传质效率下降。
[Abstract]:In this paper, the wall flow effect of liquid phase in packed column, the "amplification effect" caused by uneven fluid distribution in a wide range and radial flow are studied by thermo-model experiments. In a 800mm industrial scale distillation column with diameter, ethanol and water are used as material system. Under the condition of total reflux, the hydrodynamic properties and mass transfer properties of plate corrugated packing and wire mesh packing of the same size for paperback and vertical packing were studied. Compared with paperback plate corrugated packing, vertical packing has an average reduction of 36.52 pressure drops per meter of packing, unit theoretical plate pressure drop of 28.2424 and equal plate height of 18.15 percent. The pressure drop of the unit theoretical plate is not obvious, but the average height of the equal plate is increased by 10.99. the vertical packing designed this time is divided into eight small mass transfer units, the mass transfer units being independent of each other. It is hoped that the radial flow of the liquid will be cut off, thus solving the problem of uneven distribution of fluid in the packing, reducing the amplification effect of the packed tower and improving the mass transfer efficiency. The mass transfer efficiency of the two kinds of vertical packing is lower than that of the corresponding paperback packing, which is contrary to our expectation, which shows that the idea of the vertical packing tower is not in accordance with the actual situation. A new liquid distributor is used in the vertical packing tower. The distribution quality of the distributor is preliminarily evaluated by Perry method, and the results are verified by hydraulic experiments. The results show that the distribution quality of the distributor is uniform. The distribution performance is good. At the same time, it is proved that there is no initial uneven distribution problem in the experiment mentioned above. By analyzing the mechanism of liquid flow distribution in vertical packed column, The mathematical model of wall flow for vertical packing is established. It is considered that vertical packing basically solves the radial flow problem of fluid, but the actual wall flow rate is increased due to the block structure. The preliminary design of vertical packing does not take into account the axial redistribution of the liquid, which makes the local uneven distribution of the liquid more serious, the gas-liquid contact condition is poor, and the mass transfer efficiency is decreased.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ053.5

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