Optimal designing of cracking tower for waste tires based on heat and mass transfer model (I) Model development
A new vertical cracking tower with multiple hollow disks was developed, which could pyrolyze waste tires into carbon black, liquid oil and fuel gas.Based on the assumptions of annular granular heap, constant angle of repose and uniform physical properties, a mass transfer model in the cracking tower for waste tires was presented.The equations for calculating several important parameters, such as height and volume of each granular heap, retention time, effective covering ratio, critical capacity were provided along with the new mass transfer model.According to the penetration model of particle heat transfer and kinetic model of tire pyrolysis, the exit temperature and rubber remnant content in granular heaps were effectively predicted by a straightforward stepwise calculation procedure, and the maximum pyrolysis capacity was predicted as well.The theoretical results predicted with the heat and mass transfer model were in satisfactory agreement with experimental data from a 3000 t·a -1 pilot-plant.