Research On Design And Theory For Comminution Of Woody-Biomass And Large-Sacle Milling Equipment

Scale comminution is a necessary link for the utilization and industrialization of woody-biomass energy. However so far, there are not pulverizers which are suitable for large-scale production of crushing woody-biomass on the market, and the study on theory of pulverized woody-biomass and large-scale milling equipment is few, which lead to the large-scale and industrial use of woody-biomass energy face practical difficulties. Therefore, it is imperative to take in the study of comminution theory and process on the characteristics of woody-biomass, in order to gain the manufacturing large-scale milling equipments which have higher efficiency and lower power consuming as soon as possible.In this paper, research status on comminution technology and equipment in domestic and abroad was summarized, appropriate particle size for usual utilization of woody-biomass was made sure. Based on the analysis to the basic physical properties, which comminution model of woody-biomass is the superposition of the volume comminution model and the surface comminution has been brought forward. Matrix model of pulverized process and dynamic model of comminution have been established. Experiment for measure moisture content and density of woody biomass and test for pulverized performance of woody biomass were carried on, the influence of the density and pretreatment of raw materials to comminution characteristics of woody biomass has been derived, which provided the reference for decision-making production process of woody-biomass, and the design of comminution machinery.The comminution method for powder size of millimeter is determined according to the basic physical properties as well as comminution model of woody-biomass. Based on the analysis of raw material gathering, drying methods and the series of comminution, eight kinds of comminution process were put forward, the optional comminution process was decision-making out by Pugh matrix evaluation, and then a reasonable scale milling process for the bio-oil production line with the annual throughput of 3,000 tons was established.In the light of TRIZ (Theory of Inventive Problem Solving) in the conceptual design of the equipments can help the designer to discover the main problem quickly and provide principles for solving the problem improving the efficiency and the level of the design consumedly, the innovative conceptual design for woody biomass mill with safety, small powder size,higher efficiency and lower power consuming was directed by the methodology of TRIZ, and twelve conceptual projects were acquired. After the evaluation and synthesis to conceptual schemes, the final project(axial vibration sieve-type) and two storage projects(double-screener and dual-rotor structure) were determined.Study on comminution mechanism of the scale milling machine was made, the basic fracture forms of woody-biomass were put forward and the qualification of the crack automatic extension was established. Research and analysis of the material effective impact way and effective stress were made, movement model of effective impact between powders was established, which provided the reference for the design of scale comminution machinery.According to the theoretical study and experimental results, the structural design of axial vibration sieve-type milling machine was conducted. Innovative design of vibrating screen, which vibrating along the rotor axial can not only improve the screening efficiency, but avoid the hammer-break screen and extend the screen life as well as. Without controling amplitude strictly, makes the operation easy to adjust, reduce costs and increase of security.Virtual prototype simulation research on key components of milling machine was conducted. The structure of the rotor components was determined according to geometric simulation. Hammer static analysis, spindle static analysis and vibration mode analysis were directed based on ANSYS, research on dynamic characteristics of rotor and critical speed was made sure, rotor dynamic balance analysis was conducted based on ADAMS, which verify the safety and reliability of the design of the milling machine.The research methods and results could provide reference for the design and theoretical study on woody-biomass comminution machinery, and provide technical support or reference for the research on comminution technology and equipment of woody-biomass with higher efficiency and lower power consuming, as well as has certain reference value to promote the progress of woody-biomass comminution technology.