Name: DERIKSON ELIAS DOS SANTOS
Publication date: 24/03/2025
Examining board:
Name |
Role |
|---|---|
| DANIEL DA CUNHA RIBEIRO | Coorientador |
| MARCELO SILVEIRA BACELOS | Presidente |
| RENATO NASCIMENTO SIQUEIRA | Examinador Externo |
| ROCHKHUDSON BATISTA DE FARIA | Examinador Interno |
Summary: The pyrolysis of polyethylene/aluminum composite (LDPE/Al) in a fluidized bed produces fuels derived from Tetra Pak waste and recovers aluminum with high purity, thereby reducing the environmental impacts of the extractive industry. However, binary mixtures of sand and polyethylene/aluminum composite can segregate, decreasing the heat transfer rate and leading to bed defluidization. Predicting the mixing index using a 2D-laminar model with the Syamlal drag equation aims to determine operating conditions with low segregation levels, especially during reactor startup. The prediction of the mixing index through a model associated with experimental design has not yet been explored in the literature. For this reason, using a 24 experimental design, this work aims to evaluate the model’s predictive capability, considering the effects of the restitution and specularity coefficients on the mixing index in a fluidized bed. The validated model predicts the effects of the velocity ratio (V/Vmf), diameter ratio (DC/DS), and specularity coefficient (SC) on the bed mixing index, considering a significance level of 10%. For the top region, the results show that lower SC values and higher DC/DS ratios promote particle mixing. The CFD simulation also highlights the impact of the specularity coefficient on the flow regime transition from bubbling to slugging. This research contributes to the design and proper operation of the fluidized bed reactor, strengthening the route for polyolefinic waste valorization toward fuel production and aluminum recovery from Tetra Pak packaging.
