Study on characteristics and parameter optimization of medical waste crushing process

Non-incineration friction heat treatment (FHT) technology has become an advanced medical waste treatment nowadays. To investigate the influence of different working parameters on crushing characteristics during FHT, the process of medical waste crushing with mixed materials (PE, PVC, SiO2) was studied and simulated based on discrete element method (DEM) by adopting the Hertz-Mindlin contact model and Tavares crushing model. The effects of different transverse blade contact angles (68 degrees similar to 102 degrees), knife shaft speed (920-1000 r/min) and material ratio (1-5) for the crushing process were obtained. Using the maximum wear depth of transverse blade and the average particle size after crushing as the target response, an improved genetic algorithm was used to optimize the process parameters. With a comprehensive evaluation method, the best combination of parameters for the crushing process was determined: transverse blade contact angle of S68 degrees, knife shaft speed of 1000 r/min, material ratio (plastic: glass) of 5:1.