机构地区:[1]北京科技大学能源与环境工程学院,北京100083 [2]冶金工业节能减排北京市重点实验室,北京100083 [3]清华大学核能与新能源技术研究院,北京100084
出 处:《农业机械学报》2017年第12期86-97,共12页Transactions of the Chinese Society for Agricultural Machinery
基 金:国家重点研发计划项目(2017YFC0210303;2016YFB0601305)
摘 要:为研究扬料板对实验室级回转筒内秸秆碎料发酵热均匀化速度的影响,需研究筒内二元秸秆碎料颗粒的混合速度。基于图像分析,建立了研究二元秸秆碎料颗粒混合度Imix及完全混合时间Tc的方法,并用Visual Studio编写了分析软件。依据实验室级回转筒设计实验台,采用完全实验、分析软件和正交分析法,研究了直扬料板对Tc的影响。结果表明:对实验室级回转筒而言,在对Tc的影响上,板长大于板数,两者数量级相同,均表现显著,并相互耦合;宏观效应曲线上,Tc随板长增加类余弦函数规律变化,随板数增加类指数函数规律变化;Tc向"单+长板"和"多+中长板"两级化降低,向"多+短板"和"多+长板"两级化升高,4块板55%筒体半径长度扬料板情况下混合最快。不当的扬料板选择,反而会降低筒内料发酵热的均匀化速度,选用扬料板时,应采用"多+中长板"方案。最后,基于摄像结果分析了颗粒的运动模式、扬料板的作用过程、扬料板作用下的物料混合机理,归纳总结了不同长度/数量的扬料板作用下的颗粒运动模式,完成实验室级回转筒内物料运动模式的分解、定性研究。对于工业级回转筒,可参考本文所提出方法进行实验研究。Annual production of straw is 600 to 800 million tons in China. Dr. LI Shizhong solid-state fermented crushed straw material to acquire ethanol. However,the fermentation heat in bed often over accumulate and kill the yeast,as crushed straw material has low heat conductivity. Dr. Li use rotary drum with straight plates as fermentation drum to solve the problem. The length of plates and the number of plateshasgreat influence on movementand mixing of crushed straw material. However,there is less study in this area. In order to study the influence,section test platform was designed referred to laboratory level rotary drum. The drum can connect 1/2/4 plates andthe length of plates can adjust to 15%/35%/55%/75% ratio of drum( R). The material filling ratio and rotary speed is the same as laboratory level rotary drum: 50%,1 r/min. Some of the material was colored black while the other remains uncolored. They are laid in drum orderly to form acolored and an uncolored material layer. The two layers will mix with drum rotation,and the bed section color will change at the same time. Therefore,the section color can measure the mixing degree of colored and uncolored material. The faster the section color turn uniform grey,the faster thematerial totally mixed. The faster the material totally mixed,the greater the promoting effect of plates on averaging bed's fermentation heat. The method to measure mixing degree was built based on image analysis,as shown in figure 2. Mesh the bit-mapped picture and calculate the number of uncolored material grids( N0) and all material grids( N) as the black pixeldensity interval between themare different. The quotient( Imix) of N0 divided by N is dimension less and will turn to 0 from 0. 5 along with mixing and can mark the mixing degree. The time Imix-time fitting line turn 0 is the complete mixing time of colored and uncolored material( Tc). Data analysis resultshows that: Imixis the most accurate in the case of grid size 8 mm; black pixel density [0. 1,0. 7]marks t
分 类 号:TK6[动力工程及工程热物理—生物能]
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