Mathematical Modelling of Plastic Waste Pyrolysis Kinetics

In this work, mathematical models were developed and validated in order to monitor the optimal design and operation of the pyrolysis reactors. Mathematical models for plastic waste pyrolysis kinetics were developed. The simulated models are reliable as it predicted the experimental results and thermo-gravimetric properties of HDPE (its types/kinds), LDPE and PP types of plastic wastes. Pyrolysis temperature of plastic waste pyrolysis increases as the density and hardness of plastic waste types increases i.e. from HDPE to PS. At the same temperature HDPE laminate shows a higher rate of pyrolysis than that of HDPE pellets and HDPE powder. The results of the simulation (temperature profile for a reactor of 0.44m length using LDPE) depicts that during the first stage of the pyrolysis of the plastic waste type, the temperature increases rapidly from 100K to 700K. At temperatures 700K to 1000K fast or flash pyrolysis was observed between 0.07m to 0.37m reactor length. It can be concluded that pyrolysis temperature of plastic waste increases as the density and hardness of plastic waste types increases which implies that the conversion rate increases with the extent of branching (HDPE<LDPE<PP<PS), as HPDE chains are not branched at all, LDPE chains have some branches while PP and PS chains are very high.