针对热敏物料精馏的降液式再沸器的研究

发布时间：2018-03-11 04:30

本文选题：热敏物料　切入点：降液再沸器　出处：《天津大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前,在工业生产中热敏物料的分离和纯化方法主要是精馏,但热敏物料的汽化装置容易出现结焦、堵塞的现象。因此,本文提出一种新型再沸器-降液再沸器,并对降液再沸器内流体分布不均匀问题和降液管内强化传热问题进行了研究。首先,本文对降液再沸器流体分布不均匀性进行了实验研究,考察了不同流量下,圆锥形导流件的结构和位置对降液再沸器流体分布不均匀系数ξ的影响。实验结果表明,当降液式再沸器的封头内充满液体时,在封头内加入适当的圆锥形导流件有利于流体的均匀分布。在七种导流件中,当导流件的圆锥角角度为120度、底边直径的大小为封头内径的0.5倍、导流件顶端距离封头进液管管口的竖直高度为封头总高度的0.1倍时,导流件的导流效果较好,此时各个流量下降液管内分布不均匀系数ξ减小了54%~69%,(qi-q)max/q的最大值为3.21%,压降增大了4.3%~16.7%。其次,为了研究降液管内的强化传热,本文通过FLUENT建立了内置连续扭带和间断扭带的降液管模型,模拟了单管内流动和传热特性,考察了内置不同扭带时管内传热的努赛尔准数、阻力因子和传热效果综合评价因子(PEC)的变化。由模拟结果可知,当以水为工作介质并且降液管管内雷诺数在9952~59712之间时,连续扭带管与光滑管相比管内传热系数和阻力系数均增大,但是PEC均小于1。导致这种现象的根本原因是流动阻力过大。因此,减小阻力系数可以提高内置连续扭带降液管管内流体的综合传热效果。与连续扭带相比,内置间断扭带的降液管管内传热系数和阻力均有所减小,但是传热综合效果评价指标PEC均增大。当间断扭带的间断距离为节距的2倍时,管内传热的PEC为1.05~1.33,有效地提高了综合传热效果。
[Abstract]:At present, distillation is the main method of separation and purification of thermosensitive materials in industrial production, but the vaporization device of thermosensitive materials is prone to coking and clogging. Therefore, a new type of reboiler, down-liquid reboiler, is proposed in this paper. The non-uniformity of fluid distribution in down-flow reboiler and the problem of enhanced heat transfer in down-flow tube are studied. Firstly, the non-uniformity of fluid distribution in down-flow reboiler is studied experimentally, and the different flow rates are investigated. The influence of the structure and position of the conical diversion on the non-uniform coefficient of fluid distribution in the down-flow reboiler is obtained. The experimental results show that when the head of the down-flow reboiler is filled with liquid, The addition of a proper conical diversion to the head is beneficial to the uniform distribution of the fluid. In the seven types of diversion, when the conical angle of the diversion is 120 degrees, the diameter of the bottom edge is 0.5 times the inner diameter of the head. When the vertical height of the top of the diversion piece is 0.1 times of the total height of the head, the diversion effect of the diversion piece is better. At this point, the non-uniform distribution coefficient 尉 of each flow drop fluid pipe decreases the maximum value of 54qi-qi-qnx / Q to 3.21, and the pressure drop increases by 4.3% 16.7. Secondly, in order to study the enhanced heat transfer in the down-flow tube, the maximum value is 3.21, and the pressure drop increases by 4.3% to 16.7.The second, in order to study the enhanced heat transfer in the downflow tube, In this paper, a down-flow tube model with continuous and discontinuous torsion bands is established by FLUENT. The flow and heat transfer characteristics in a single tube are simulated, and the Nussel number of heat transfer in a tube with different torsion bands is investigated. The variation of drag factor and heat transfer effect evaluation factor (PECs). The simulation results show that when water is used as the working medium and the Reynolds number in the downflow pipe is between 9952 and 59712, Compared with the smooth tube, the heat transfer coefficient and the resistance coefficient of the continuous torsion tube are increased, but the PEC is less than 1. The fundamental reason for this phenomenon is that the flow resistance is too large. Reducing the resistance coefficient can improve the comprehensive heat transfer effect of the fluid in the down-flow tube of the built-in continuous torsion band. Compared with the continuous torsion strip, the heat transfer coefficient and resistance in the down-flow tube with the built-in discontinuous torsion belt are reduced. When the discontinuous distance is 2 times of the pitch distance, the PEC of heat transfer in the tube is 1.05N 1.33, which effectively improves the comprehensive heat transfer effect.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ051.65

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