Experimental Data of Grinding Dried Fibrous Plant Materials

Abstract

Introduction. Developing a method for energy-efficient grinding of fibrous vegetable raw materials to avoid the clogging of grids remains an urgent task. The aim of the research is to study the process of grinding dried fibrous plant materials and to estimate the influence of the device operating characteristics on the quality of grinding and the process energy intensity. Materials and Methods. The experimental apparatus is a rotor grinder. Its working bodies are alternate knives and hammers. When a hammer is in motion, its triangle side creates the reduced pressure area. There was studied the influence of the linear velocities of knife motion and of feed of raw materials on fractional composition of the grinded materials, grinder productivity, and grinding specific energy capacity. Results. It is found that the change in the fractional composition of the grinded product occurs when the speed of the rotor knives increases. Optimal range of knife speed for producing the product of the required fractional composition is 55‒75 m/s. The increase in the speed leads to increasing productivity, but is accompanied by the growth of specific power intensity. If the rotor speed is constant, the increase of raw material feed increases the grinder productivity, but only up to a certain value. After that, the productivity decreases because of excessive filling of the working chamber with raw materials and clogging of the grates. For each value of the knife speed, there is an optimal feed that ensures the maximum productivity. High values of knife speed lead to significant energy intensity of the process and overgrinding of raw materials. Therefore, the optimal range of knife speed is 55‒65 m/s. Discussion and Conclusion. Effective grinding of raw materials is achieved through lower energy capacity of grinding process and absence of grate clogs resulted from separating particles from the surface of plants to be grinded.