Optimized test of running parameter on rind-pith separation equipment for corn stalk

Abstract: With the development of agriculture in China, the total annual production of straw is over 700 million tons, including more than 200 million tons of corn stalk. In general, corn stalk was utilized as the common domestic fuel and livestock feed, and the remaining straw was burned in fields in the past, which led to waste of resources and pollution of environment. With economic development, technological progress, and the growing demand for resources (including energy resources), valuable utilization of corn stalk is emphasized at home and abroad, such as separately using rind, pith and leaves to achieve maximum value according to their different chemical compositions. Therefore, rind-pith separation equipment for corn stalk has been developed in China. So far, the separating quality, adaptability, operational reliability and productive efficiency of rind-pith separation equipment for corn stalk are still low. Further research is needed, including deeply researching and developing the key mechanisms for rind-pith separation equipment.For effective separation of the rind and pith of a variety of corn stalk (especially corn stalk with a high moisture content obtained in the corn harvesting season) and determination of the operation parameters of rind-pith separation equipment, a leaf-stripping mechanism and pith-stripping mechanism of rind-pith separation equipment for corn stalk had been experimented on. By preliminary experiments and analysis, two stages of leaf-stripping technology of blasting, stripping and rubbing had been used and conformed. Key parameters of leaf-stripping mechanism and the pith-stripping mechanism had been determined by multi-factor orthogonal rotation combination experiments. By an analysis of the experiments for the leaf-stripping mechanism, the significant factor was the bottom width of the U groove plate and the feeding speed for corn stalk with the third significant factor being, the rotation speed of the leaf-stripping roll. For the pith-stripping mechanism, the most significant factor was the feeding speed for the corn stalk, the second significant factor was the rotation speed of the pith-stripping roll, and the third significant factor was the clearance between the pith-stripping blade and supporting plate. By a comprehensive analysis of the existing experimental results, the main movement parameters of rind-pith separation equipment for corn stalk were as following: feeding speed for corn stalk 1.2～1.3 m/s, rotation linear speed of leaf-stripping roll more than 5 m/s, rotation linear speed of the pith-stripping roll more than 5.8m/s.Based on the optimization parameters of the above experiments, the four-pass rind-pith separation equipment for corn stalk was designed. The separation equipment was mainly composed of a feeding mechanism (including a feeding table and feeding roll), two leaf-stripping mechanisms, an opening and flattening mechanism (mainly cutting, opening and flattening corn stalk), a pith-stripping mechanism, and an output mechanism (mainly transportation rind out of the equipment). By experiments, the separation equipment was found to be practical to separate corn stalk from about ten percent moisture content to about seventy percent moisture content. Then， the separation equipment was examined and tested, and overall productivity was more than 0.5 t/h according to corn stalk with about twelve percent moisture content, the leaf-stripping percent was more than ninety-seven point six percent, and the pith-stripping percent was more than ninety-five point seven percent. The above results could be served as a guide for the designing and optimizing of rind-pith separation equipment for corn stalk.