高分子中空纤维传热元件的强化传热与应用研究

发布时间：2018-03-24 19:55

本文选题：高分子中空纤维　切入点：弓形折流挡板　出处：《天津大学》2015年硕士论文

【摘要】：换热设备是工业生产过程中实现物料之间热量交换的重要设备。但是传统的金属换热设备由于其腐蚀和易结垢问题的存在,在高盐、高酸碱、高硬度环境下的应用受到了限制。高分子中空纤维传热元件制作的换热设备由于其具有良好的抗腐蚀和防垢性能,因而受到关注。本文采用高分子中空纤维作为传热元件,研制了具有弓形折流挡板的新型中空纤维换热器,对此进行了Fluent模拟和实验研究。结果表明,所建立模型的模拟结果与实验结果吻合较好。通过对比发现,增加了折流挡板以后,中空纤维换热器的总换热系数相对于无折流挡板换热器提高了35%;壳程的进出口压降提高了14%;壳程热阻所占总热阻的比例从59%-70%下降到了34.5%-46.7%;壳程换热系数与壳程进出口压降的比值得到了明显的提高。综合分析可知,壳程增加折流挡板能够显著提高中空纤维换热器的换热性能,实现了对中空纤维换热器换热过程的强化。本文将高分子中空纤维换热组件作为蒸发器组件,以此搭建了单效和三效蒸发装置。分别以纯水和质量分数3%的NaCl溶液作为进料液,考察了操作工况对蒸发装置的产水量和造水比(GOR)的影响规律。结果表明,对于单效和三效蒸发装置,装置的GOR和产水量均随着进料温度和蒸发温差的升高而增大。随着进料流量的提高,装置的产水量不断增加,而GOR保持稳定。当进料液为纯水时,随着进料流量的提高,单效和三效蒸发装置的GOR分别稳定在0.85和1.65左右。当进料液为NaCl溶液时,随着进料流量的提高,单效和三效蒸发装置的GOR分别稳定在0.76和1.48左右。在各效的进料流量为90L/h、生蒸汽温度为97°C、进料温度为78°C、总蒸发温差为12°C的条件下,当进料液为纯水时,三效蒸发装置的产水量达到了6.55kg/h;当进料液为NaCl溶液时,三效蒸发装置的产水量达到了5.9kg/h。另外,当进料液为NaCl溶液时,单效和三效蒸发装置的产水量和GOR均小于相同条件下进料为纯水时装置的GOR和产水量。本课题的意义在于为强化高分子中空纤维换热器的换热性能提供了一种新方法,同时为利用高分子中空纤维设计高效蒸发工艺奠定了基础。
[Abstract]:Heat exchanger is an important equipment to realize heat exchange between materials in industrial production process, but the traditional metal heat exchanger is in high salt, high acid and alkali due to its corrosion and easy scaling problem. The application in high hardness environment is limited. The heat exchanger made of high molecular hollow fiber heat transfer element has attracted much attention because of its good corrosion and scale resistance. In this paper, the high molecular hollow fiber is used as heat transfer element. A new type of hollow fiber heat exchanger with bow baffle is developed. The Fluent simulation and experimental study are carried out. The results show that the simulation results of the model are in good agreement with the experimental results. After adding the baffle, The total heat transfer coefficient of hollow fiber heat exchanger is 35% higher than that of non-baffle heat exchanger; the pressure drop of inlet and outlet of shell side is increased 14%; the proportion of heat resistance of shell side decreases from 59-70% to 34.5-46.7%; the heat transfer coefficient of shell side and shell side enter and exit. The ratio of mouth pressure drop is obviously increased. The heat transfer performance of the hollow fiber heat exchanger can be improved by increasing the baffle baffle on the shell side, and the heat transfer process of the hollow fiber heat exchanger can be strengthened. In this paper, the polymer hollow fiber heat transfer module is used as the evaporator assembly. Using pure water and NaCl solution of 3% mass fraction as feed solution, the effects of operating conditions on water yield and water ratio of evaporator were investigated. For single-effect and three-effect evaporators, both GOR and water yield increase with the increase of feed temperature and evaporation temperature difference. With the increase of feed flow rate, the water production of the unit increases continuously, while the GOR remains stable. When the feed liquid is pure water, With the increase of feed flow rate, the GOR of single-effect and three-effect evaporator is about 0.85 and 1.65, respectively. When the feed liquid is NaCl solution, with the increase of feed flow rate, The GOR of single-effect and three-effect evaporator is about 0.76 and 1.48.The feed flow rate of each effect is 90L / h, steam temperature is 97 掳C, feed temperature is 78 掳C, total evaporation temperature difference is 12 掳C, and when the feed liquid is pure water, The water production of the three-effect evaporator is 6.55 kg / h; when the feed solution is NaCl solution, the water yield of the three-effect evaporator is 5.9 kg / h. In addition, when the feed solution is NaCl solution, The water production and GOR of single-effect and three-effect evaporators are smaller than those of pure water under the same conditions. The significance of this project is to provide a new method for enhancing the heat transfer performance of polymer hollow fiber heat exchangers. At the same time, it lays a foundation for the design of high-efficiency evaporation process using macromolecule hollow fiber.
【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】：TQ342.8;TQ051.5

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