چكيده به لاتين
Pyrolysis process is one of the methods of waste polymer management. This process reduces environmental hazards and is economical as well and produces the valuable products such as fuel which can cover part of the fuel demands. Thus, understanding the mechanism, reaction and transport phenomena is necessary to improve and optimized the process. In this way, in the present study, the pyrolysis of waste tire in a rotating drum has been experimentally and numerically investigated. Experimental studies were done to indicate the parameters which are affect the pyrolysis process. Also the efficiency of the process was calculated in different conditions. In the numerical study the Eulerian-Eulerian approach along with the kinetic theory of granular flow was used to simulate the multiphase system and the interactions between them. In order to comprehensively investigate the pyrolysis process in a rotating bed, numerical study has been carried out in their individual sections (i.e. hydrodynamics, heat transfer and pyrolysis reaction) and the effects of different parameters have been described. The accuracy of the numerical model which is developed for hydrodynamic and heat transfer by comparing results with other experimental data in this subject, and accuracy of the pyrolysis reaction model by comparing the experimental data were confirmed. Finally, conditions affecting hydrodynamics, the heat transfer, and pyrolysis reaction in the rotating bed using the numerical model has been conducted.
The obtained results of experimental researches are in agreement with the results reported by other researchers. In this regard by increasing the temperature of rotating bed, the amount of liquid will be reduced (about 14% from 42% at 550°C to 35% at 1050°C) and the amount of gas will be increased from 21% % at 550°C to 30% at 1050°C. By increasing the inert gas flow rate, the produced gas in the hot zone (reaction zone) will be reduced and secondary reactions will be minimized, which will be lead to an increase in the amount of liquid product from 31.44% at 250 ml/min to 38.44% at 510 ml/min. On the other hand, the result of the numerical model showed that Computational Fluid Dynamics (CFD) simulation has a high probability for estimating the hydrodynamic behavior, heat transfer, and reaction of the gas-solid mixture in the rotating bed. The results of the CFD model indicated that, due to the temperature dependence of the kinetic model of pyrolysis of waste tires, with increasing heating rate, the conservation rate of waste tire to the product will be fast.
Keywords:
Pyrolysis, rotary reactor, CFD simulation, hydrodynamics, heat transfer, waste tire, kinetic model.
