Two-dimensional mathematical model of liquid fuel combustion in bubbling fluidized bed applied for a fluidized furnace numerical simulation

Abstract

Lately, experimental methods and numerical simulations are equally employed for the purpose of developing incineration bubbling fluidized bed (BFB) facilities. The paper presents the results of the 2-D CFD model of liquid fuel combustion in BFB, applied for numerical simulation of a fluidized bed furnace. The numerical procedure is based on the two-fluid Euler-Euler approach, where the velocity field of the gas and particles are modeled in analogy to the kinetic gas theory. The proposed numerical model comprises energy equations for all three phases (gas, inert fluidized particles, and liquid fuel), as well as the transport equations of chemical components that are participating in the reactions of combustion and devolatilization. The model equations are solved applying a commercial CFD package, whereby the user submodels were developed for heterogenic fluidized bed combustion of liquid fuels and for interphase drag forces for all three phases. The results of temperature field calculation were compared with the experiments, carried out in-house, on a BFB pilot facility. The numerical experiments, based on the proposed mathematical model, have been used for the purposes of analyzing the impacts of various fuel flow rates, and fluidization numbers, on the combustion efficiency and on the temperature fields in the combustion zone.