【作者】 张世军；

【导师】 蒋恩臣；

【作者基本信息】 华南农业大学 ， 农业机械化工程， 2016， 硕士

【摘要】 生物质能源因具有优良的环境友好性和可再生性而备受关注,开发利用生物质能源对废弃资源回收利用、能源结构改变、环境保护和改善等具有重大意义。为了解决生物质连续热解装置的螺旋绞龙与热解管因热变形而发生的机械干涉现象,研究了一种用于生物质热解的无轴柔性连续输送装置,设计了该无轴柔性螺旋,以稻壳、木屑、油茶壳和黄豆为输送物料,探究了螺距、转速和有轴无轴等因素对输送性能的影响。主要研究结果如下:以螺旋输送装置处理量和处理时间为依据,研制了直径为70mm,长度为1570mm,螺距分别为39.3mm、57.2mm和77.3mm的无轴螺旋以及螺距为41.6mm的有轴螺旋;搭建生物质连续输送装置。对稻壳、木屑、油茶壳和黄豆四种物料的堆积角,与管壁的摩擦系数,容重和粒径参数进行了测试分析。实验结果表明:柔性螺旋输送装置对物料的输送效率随着螺距的增加而增强;在中低转速下,柔性螺旋输送装置对物料的输送效率随转速的增加呈线性增强,表明物料的输送量和通过时间可通过调节电机转速实现精准控制,在高转速下,稻壳、木屑和黄豆依然满足线性增强关系;无轴螺旋比有轴螺旋的输送能力高20-30%,且输送过程平稳,避免了物料在输送装置与输送管之间发生挤压,进而出现死机的现象。对物料的输送过程进行了运动学和动力学分析,在螺旋叶片的支持力和摩擦力、管壁的支持力和摩擦力、物料自身重力等多种力共同作用下,物料实现螺旋运动。当螺旋叶片升角?和物料与叶片之间的摩擦角?之和?????2/时???,物料在螺旋叶片推动作用下既做轴向转动又做径向移动;当?????2/时???且?????2/,物料处于摩擦角以内,只做径向转动,无轴向移动;物料轴向和径向移动分速度与物料在输送管中所处位置和螺旋叶片螺距有关。对物料进行标记处理,观察记录物料运动状态,实验结果表明:不同物料在同一输送状态下的轴向移动速度相差不大,物料在输送装置中的实际输送时间比理论高30%左右。更多还原

【Abstract】 Biomass energy is widely concerned because of its excellent environmental friendly and renewability. Development and utilization of biomass energy has significant importance in recovery of waste resource, transformation of energy construction,environmental improvement and protection, etc. In order to solve the mechanical interference for thermal deformation between screw auger of biomass pyrolysis and pyrolysis tube, a kind of flexible shaft-less screw conveyor of biomass pyrolysis was investigated experimentally and the parameters of flexible shaft-less screw blade was designed. Taking rice husk, wood chips, camellia oleifera shells and soybeans as convey materials, the effect on convey performance since the factors of the pitch, speed and shaft or shaft-less was explored. The main contents are as follows:The design was based on the treatment capacity and the residence time of screw conveyor to meet the different demands of materials by blade diameter and pitch. The shaft-less convey blades, the diameter of 70 mm and the pitches of 39.3mm, 57.2mm and77.3mm,and the shaft convey blade, the diameter of 70 mm and the pitches of 41.6mm,were processed. The accessory equipment were designed and processed to construct continuous screw conveyor of biomass pyrolysis.The angle of repose of rice husk, wood chips, camellia oleifera shells and soybeans,friction coefficient with pyrolysis tube, density and characteristic parameter of particle size were tested. The results showed that: The treatment capacity of the device is enhanced with the increasing pitch. At the lower speed, the treatment capacity of the device is strengthened with the increasing speed of motor linearly, indicating that the treatment capacity and residence time can be controlled precisely by adjusting the motor speed; The treatment capacity of shaft-less screw conveyor is 20-30% better than a shaft one, and the conveyprocess is more smoothly, avoiding the crash phenomenon for the pinched of the material between the delivery device and the delivery tube efficiently.The mechanics and kinematics of the convey process was analysised. Demonstrated show that the material rotational speed is less than the screw blade resulting from interactions among the friction and support of the screw blade, the friction and support of the screw tube, self-gravity of the material and resulting in the material move toward a given direction. The movement condition was analysised from the sum of the angle of lead and the angle of repose of: When ?(27)(10)????? 2/,, the material both do radial rotation and axial moving; When,,(28)(10)??(10)????????2/2/, the material do radial rotation only. The axial and radial velocity of the material is related to the position and the pitch of the screw blade. Marked the material and observed and recorded the convey process material. The results showed that: there is no big difference among the axial velocity of different materials. The actual residence time is about 30% more than the theoretical.更多还原