Study On Flexible Screw Conveyor Of Biomass Pyrolysis

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.