CFD simulation of combustible solid waste pyrolysis in a fluidized bed reactor

Abstract

Computational fluid dynamics (CFD) simulation of combustible solid waste (CSW) pyrolysis in a fluidized bed reactor with feeding rate of 5 kg/h was performed in this study. The multi-phase flow was simulated using the Euler-Euler method, and a multi-component and multi-step reaction method was adopted to describe the pyrolysis process of CSW. The user-defined functions (UDF) of heterogeneous reactions were programmed and coupled with the computational fluid dynamics (CFD) software. The simulation methods used were validated by comparing the simulated temperatures and product yields with the experimental results. Simulation results also indicated that the flow regime in the fluidized bed turned into stabilized fluidization gradually over pyrolysis time, and the mass flow rates of pyrolytic products at the outlet fluctuated within the range of ±10%. Pyrolysis temperature had the greatest effect on the product yield, while initial bed height had the most significant influence on product fluctuations. The CFD simulation results presented in this study provide valuable reference for the design and optimization of waste pyrolysis process.