CFD analysis of fluidized beds using wastes from post-consumer carton packaging

- FBs fluid dynamics comprised sand and LDPE/Al mixtures were investigated.
- CFD model predicts the fluidization regime of bed mixtures used.
- Bed particle segregation can be avoided using air velocity of 1.5 umf.
- Beds with 20% LDPE/Al is suitable for pyrolysis.

Fluidized bed reactors can be used for fast pyrolysis of polyethylene-aluminum composite (LDPE/Al) to achieve good gas-solid mixing together with high rates of heat and mass transfer in bed columns. Pyrolysis of waste from post-consumer carton package (i.e., polyethylene-aluminum composite) reduces the manufacturing costs of new packages as it permits to produce them using the recovered aluminum and polyethylene in the process. Therefore, this research aims at modelling and analyzing the gas-solid flow in fluidized beds composed of sand and LDPE/Al mixtures. For all mixtures used, results show that gas-solid flow can be well described by the Eulerian-Eulerian Granular model coupled with the usage of parameterized Syamlal-O'Brien's model for momentum transfer between phases. For bed mixtures with up to 20% LDPE/Al composite, the bed pressure drop can be predicted by the model with an error of less than 18%. In addition, for bed mixtures operating at air velocities higher than 50% minimum fluidization, significant segregation of LDPE/Al was not observed. This result indicates that bed mixtures can achieve a good gas-solid contact in the bubble fluidization regime and can be used as a fluidized bed reactor for pyrolysis of wastes from post-consumer carton packages.

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