【作者】 李琼；

【导师】 靳世平；

【作者基本信息】 华中科技大学 ， 工程热物理， 2008， 硕士

【摘要】 随着化石能源的日益枯竭和环境污染的日趋严重,开发洁净可再生能源已成了紧迫的课题。生物质能源作为可储存和运输的可再生能源,其高效转化和洁净利用日益受到全世界的重视。将生物质破碎为微米级粉末进行直接燃烧,既便于存储运输,又能提高燃烧效率及燃烧温度,可扩大应用于电力、冶金、陶瓷等行业作为替代能源。生物质锯末加热升温时依次经历脱水、气化、燃烧三个主要过程。升温初期主要是内部失水,需要大量吸热,比热容随温度增加而增大;气化开始后,随着物质气化量的增加,比热容逐渐降低,因为气态物质的比热值要小于固态物质,吸热速率变缓。本文设计了一种用于生物质粉末的气力输送装置。生物质粉末粒径小、比重小、粘度较大,在下落过程中,会受空气压力而变得紧密,并且与管壁摩擦产生一定的粘滞力,影响输送的连续稳定性。该装置采用正压密相输送,在罐顶增加充压管通入流化室,同时流化室贴壁处装充气管通入粉体,两处均利用压力空气吹散团聚及粘滞的粉末,管路弯头处设计引射管产生负压促进粉末从流化室卷吸至水平输送管,由此保证输送的稳定和连续性。实验表明该装置可应用于工业高压密相气力输送系统中。另外,本文优化设计了专用于生物质粉末燃料的蓄热式旋流燃烧器,该燃烧器采用切向进料,通入二次旋流风和直流风助燃。本文采用了三种生物质粉末样品进行了燃烧实验,试验证明采用该套气力输送装置,生物质粉末燃烧状况良好。故综上所述,采用合适的气力输送装置、燃烧装置,生物质粉末化燃料具有一定的工业应用前景。更多还原

【Abstract】 As the increasingly serious problems of fossil energy depletion and environmental pollutions, exploiting the clean renewable energy resources has become the urgency. Pulverized biomass resources are the renewable energy resources that can be easily stored and transported, in addition it has high efficiency and temperature of combustion, so it can be widely applied in many industrial fields.The biomass sawdust mainly has three processes of dehydration, gasification and combustion when heated. At the beginning period of heating up, the biomass need to absorb much heat and lost the inner water, at the same time, the specific heat increase. After gasification , the specific heat decrease mainly because the specific heat of gas is less than that of solid.This paper designs a pneumatics transportation device of pulverized biomass which adopt positive pressure and dense-phase mode, it assures the stability and continuity during transportation. The ideas of designing consider several factors such as the smaller grain diameter, lower specific gravity and higher viscosity compared as pulverized coal. For the above reasons, a pressurization tube and a ejector are respectively installed on the top cover and the underside of the conveyer. This device can be applied in dense-phase and high-pressure pneumatics transportation of industry.Furthermore, swirl combustor is utilized to increase the combustion efficiency and temperature Three kinds of pulverized biomass are used to do combustion experiments. The results demonstrate that this set of pneumatics transportation and combustion devices can effectively applied in small industry if adopting some high-temperature combustion technologies.更多还原