【作者】 李斌；

【导师】 张后雷；

【作者基本信息】 南京理工大学 ， 热能工程， 2013， 硕士

【摘要】 桨叶干燥机是一种间接加热型干燥装备。本文介绍了桨叶干燥机的工作原理和干燥特点,总结了国内外桨叶干燥技术的研究进展；同时,指出了桨叶干燥和加热研究工作中公开实验数据缺乏、设计经验性强等问题。为深入研究膏体在桨叶干燥机中的干燥性能,设计了一套换热面积为3m2的桨叶干燥实验装置,包括桨叶干燥机、热源系统和测量系统等,为后续实验研究提供了条件。在实验室条件下,先后完成了市政污泥、印染污泥和固体聚乙烯颗粒的桨叶干燥和加热实验。在原样含水率为80.8%的市政污泥的干燥过程中,探讨了热介质(导热油)温度、桨叶干燥机转速及干燥添加剂对于干燥效果的影响。实验表明：在桨叶干燥机转速为22.5r/min,加热油温分别为120℃、160℃、180℃、210℃时,市政污泥干燥后的含水率分别为76.99%、67.73%、48.85%、39.38%。在加热油温为180℃,桨叶干燥机转速分别为37.5r/min、22.5r/min、7.5r/min、3.75r/min时,市政污泥干燥后含水率分别为51.69%、48.84%、40.84%、23.17%；此外,在加热油温180℃,干燥机转速7.5r/min工况下,增加5%(质量比)稻壳添加剂得到的干燥后市政污泥含水率为36.58%,堆积密度为0.7144g/mL,而未加入添加剂得到的干燥后市政污泥含水率为40.84%,堆积密度为0.5918g/mL,从概念上验证了采用合适的添加剂有助于强化干燥过程。使用桨叶干燥机对选取的印染污泥进行了干燥实验测试。在加热油温180℃,干燥机转速7.5r/min工况下,原样含水率为84.97%的印染污泥,经过桨叶干燥后含水率下降到12.77%,表明桨叶干燥机能够有效地干燥印染污泥,为桨叶干燥机在印染污泥干燥中的应用提供了初步依据。进行了固体聚乙烯颗粒在桨叶干燥机的加热熔化实验,观察了聚乙烯熔融液在桨叶干燥机内的状态变化和流动特性。定性观察结果表明,采用桨叶干燥机加热固体聚乙烯颗粒提高其流动性从而减小输送功是可行的。最后,设计了一套聚光集热型太阳能辅助桨叶干燥系统,以南京地区光照条件为例,计算了引入太阳能辅助加热的节能收益。更多还原

【Abstract】 A paddle dryer is an indirect drying equipment. Firstly, the operational principle and applied characters were introduced and the research progress about the paddle dryer technology at home and abroad was summarized. Based on that, some problems like lack of specific experimental data and more empirical for the equipment design were pointed out.Combined with these problems, a paddle dryer drying system with an area of3m2was designed, including the power part, the thermal dynamic part, the measurement part and so on. With it study on paddle dryers was conducted further through the experiments, providing the qualification for the next experiments.Drying experiments of municipal sewage sludge, textile dyeing sludge and polyethylene particles were carried out in a paddle dryer in the laboratory separately. During the drying experiments of municipal sewage sludge with the initial moisture content of80.8%, some important parameters, like the oil temperature, the speed of the paddle dryer, additives were discussed.It was concluded that with the increase of oil temperature, the drying effect was enhanced. When the speed of the paddle dryer was22.5r/min, the moisture content of the products of municipal sewage sludge as oil temperature was120℃、160℃、180℃、210℃in experiments was finally76.99%、67.73%、48.85%、39.38%separately. Within a certain range, sewage sludge had a longer period for drying at the lower speed of the paddle dryer. When the oil temperature was180℃, the moisture content of the products of municipal sewage sludge as the speed of the paddle dryer was37.5r/min、22.5r/min、7.5r/min、3.75r/min in experiments was finally51.69%、48.84%、40.84%、23.17%separately. Therefore, the products out of the paddle dryer got lower moisture contents and the smaller particles. In addition, when oil temperature was180℃, and the speed of the paddle dryer was7.5r/min, the moisture content of the products of municipal sewage sludge after drying process with mass ratio5%was36.58%, lower than40.84%without additives. And the bulk density was0.7144g/mL, higher than0.5918g/mL without additives. It was demonstrated that a better effect of drying and heat transferring was achieved by some proportion of the rice husk additives put in during the drying process from the view of definition.The drying experiments for textile dyeing sludge was performed, showing that when oil temperature was180℃, and the speed of the paddle dryer was7.5r/min, the initial sample with the moisture content84.97%was dryed to12.77%. Through the drying experiment of textile dyeing sludge, it was proved the paddle dryer was available for the drying of textile dyeing sludge. Combined with the experiments of municipal sludge sewage, it was given the instruction of the pastes drying process in the paddle dryer.The thermal and flow properties of the melt polyethylene was observed in the paddle dryer. With a good performance on thermal and flow properties, it provided another way for the use of a paddle dryer.An idea of utilizing the solar energy to heat the oil and assist the drying process was proposed. Then a parabolic trough solar collectors drying system assisted drying was designed. According to average radiation intensity in every season in Nanjing, the utilization of solar energy and the energy saving in ideal condition were calculated analyzed finally.更多还原