Breakage behaviour of enzyme granules in a repeated impact test, Pitchumani, R. (2003)donderdag, 02 april 2009
In many industries, handling or processing of relatively fragile particles takes place and predictions are required whether a significant proportion of the particles will be damaged. These processes have been designed and controlled solely on the basis of particle size and shape. Another parameter that needs to be introduced is particle strength. The stringent environmental laws demand improved particle mechanical quality, which has given rise to the need for a more accurate and fundamental particle strength measurement and its application in modelling and control of particulate processes. Particles need to show good resistance against static and dynamic loads.
The present paper deals with the study of breakage behaviour of different enzyme granules subjected to repeated impacts using a new instrument developed at the Delft University of Technology. The impact test involves bombarding the particles against a flat target repeatedly.
The main feature of this new test is its ability to impact a large number of particles against a flat target repeatedly, and generate extremely reproducible results. Testing a large number of particles has the advantage of producing statistically correct results. The repeated impacts provide information on the breakage behaviour of the particles based on their history. In the new impact test enzyme granules can undergo very low impact velocities of the order of 5 m s 1. These low impact velocities lead to attrition and chipping of the granules. The current paper presents preliminary results on the breakage behaviour of the new impact test and its basic advantages over already existing tests. Furthermore, experiments were performed on enzyme granules, and the breakage mechanisms determined, depending on the change in size and shape of the particles.