High Stability, Low Energy Consumption Ring Die Pelletizing Key Technology Research

Pellet mill is widely used in feed industry and bioenergy industry because of the feed quality it’s made is good and the production is efficient. At present, there are several disadvantages in pellet products which restrict the development of relevant industry and technology, such as lacked of stability, short service life and high energy consumption. Based on the analysis of the factors that affect the stability and energy consumption in pelleting, the high stability and low-energy pelletization techniques are analyzed. The main topics are as follows:(1) The pelleting process is divided into two stages--rolling and extruding, then forces of material in two stages are analyzed. Then based on the solution of nip angle and the height of material beds, the factors that affect pelleting process are analyzed.(2) Aim at the problem that currently ring die is easy to be broken, two new types of die hole arrangement are designed and all of three types are analyzed with finite element methods. Conclusions indicate that adopt the new arrangement is helpful to improve the ring die strength.(3) The impact of ring die width on the stress and strength of ring die have been studied, the result shows that the overall deformation increases with the increase of width.(4)The effect of linear velocity and width of ring die on the vibration of pellet mill is investigated by experimental. Furthermore, a best parameter combination which can reduced the vibration of pellet mill is obtained.(5)The rolling process of powder material is simulated and the factors that affect rolling process are studied through defining different parameters. The result shows that the powder compression quality improved with the increase of friction coefficient and diameter ratio as well as the decrease of gap of roll-die.(6)The extrusion process is simulated and the extrusion force is obtained. Then the simulation of rolling process and extruding process is combined together to optimize the parameters of pelleting.