Effects comparison of superfine pulverizing of Lentinus Edodes stem by air jet milling and wheel grinding

Air jet milling and wheel grinding were used to superfine pulverize lentinus edodes stem to improve added values. The operation parameters such as classifier rotating speed of air jet milling, host frequency and fan frequency of wheel grinding and feeding speed of two processes were analyzed and optimized using single factor test and piecewise linear fitting method. The pulverizing effect, processing time, production rate and energy consumption of two equipments were compared under respective optimized operation conditions. The results showed that the optimized rotating speed and feeding speed of air jet milling were 2400 r/min and 12 kg/h, respectively. The optimized host frequency, fan frequency and feeding speed of wheel grinding were 44Hz, 42 Hz and 5 kg/h, respectively. The superfine powder with particle median diameter (D50) less than 10μm could be obtained by both superfine pulverizing methods. Compared with wheel grinding, air jet milling pulverized powder more precisely (with narrower particle size distribution) and spent less processing time (shortened?by 56.43%), but obtained lower production rate and required higher energy consumption (4.77 times). On the whole, the wheel grinding method was more suitable for scale production of lentinus edodes stem. This research provides technical basis for the development and application of superfine pulverizing technology in lentinus edodes stem processing.