【作者】 李坤；

【导师】 靳世平；

【作者基本信息】 华中科技大学 ， 新能源科学与工程， 2016， 硕士

【摘要】 随着日益严峻的全球环境污染及一次能源短缺,以太阳能、风能、生物质能为代表的可再生能源作为能源替代及补充逐渐引起了学者的关注。生物质能源又以其具有资源丰富、分布广泛、利用途径多样等特点而被研究与利用。在诸如生物质热解与气化的利用过程中,生物质颗粒的干燥特性成为了影响生物质气化产气量和气化效率的一个非常重要的先决条件。回转窑是颗粒工业应用中的常见设备,其主要用于粒子混合,研磨,制粒,涂层,干燥等。粒子流在回转窑中的流动特性呈现出非常复杂的现象,在生物质颗粒干燥过程中,由于生物质颗粒在回转窑中各种相互作用力及动态特性非常复杂,因此掌握粒子在回转窑中的运动状态以及热交换过程、模拟颗粒在水平干燥回转窑中动力学特性对于生物质干燥来说显得尤为关键。本文主要基于欧拉连续性模型研究生物质在回转干燥窑中颗粒-颗粒,颗粒-载气,颗粒-墙壁之间的相互作用及动态特性,并运用Taguchi正交实验法分析生物质粒径大小,干燥窑回转速度,初始填充率等不同运行条件下生物质在回转窑中的运动特性和净通量特性。模拟结果表明:在本次实验中,粒径大小对生物质净通量及平均轴向混合影响较大,影响比例分别为70.06%、64.8%;初始填充率对生物质径向混合作用明显,影响比例为45.2%;另外,存在一个峰值回转窑旋转速度4rpm来使得生物质在回转窑内的运动状态达到最佳。更多还原

【Abstract】 Along with the increasingly serious global environmental pollution and energy shortage, the renewable energy, representatives of the solar energy, wind energy, biomass energy,as an alternative and complementary energy gradually gained extensive attention. With its rich resources and wide distribution, biomass energy were researched and utilized indifferent ways. In some utility methods such as biomass pyrolysis and gasification process, the drying characteristic of biomass is a very important prerequisite that influences the gas production and gasification efficiency.Rotary kiln is a common equipment in grain industry application, it is mainly used for particle mixing, grinding, granulating, coating, drying, etc. Particles flow features in the rotary kiln presents a very complicated phenomenon. In the process of biomass particles drying, due to the complex particle interactions and dynamic characteristic in a rotary kiln, knowledge of the particle motion in rotary kiln and the heat exchange process, simulating particles drying dynamics are especially critical for biomass drying.This thesis is mainly based on Euler continuity model to simulate the interactions and dynamic characters between biomass particle-particle, particle-gas and particle-wall in the rotary dryer, Taguchi orthogonal experiments also be used to analyze the net flux and other movement characteristics in different running conditions by vary particle size, rotary velocity and filling fraction. Result shows that the particle size has huge influence on net flux and axial mixing, which take a percentage of70.06%、64.8%,respectively;the filling fraction better affect radial mixing, which take a percentage of 45.2%. Furthermore,there exit a peak value of rotation speed 4 rpm in this work which offer a better performance on the movement of the biomass in the rotary.更多还原