Simulation of Combustion of Municipal Solid Waste and Coal in an Industrial-Scale Circulating Fluidized Bed Boiler

Abstract

In this paper, a three-dimensional Eulerian–Lagrangian model is established to perform the full-loop simulation of the combustion process of municipal solid waste (MSW) and coal in an industrial-scale circulating fluidized bed (CFB) boiler. On the basis of the multiphase particle-in-cell (MP-PIC) scheme, the gas phase is modeled by a large eddy simulation (LES) approach and the solid phase by discrete particle method. A comprehensive reaction model including devolatilization, combustion of char and volatiles, formation and retention of acid gas, and production and reduction of NO and N2O is incorporated into the scheme. The simulated CFB boiler consists of the chamber, cyclone, loop-seal, external heat exchanger (EHE), and diplegs. The full-loop gas–solid flow behavior and combustion characteristics are obtained. Numerical results reveal that a fast fluidization regime takes place in the chamber region, while a bubbling fluidization regime appears in the EHE. Serious wall erosion takes place in the horizo...