Numerical investigation of the oxy-fuel combustion in the fluidized bed using macroscopic model supported by CFD-DDPM

Abstract

Oxy-fuel combustion (OFC) presents a promising strategy for reducing carbon emissions from coal combustion. Traditional multiphase flow models (MFM) used for OFC simulations face challenges in integration and optimization with systems like carbon capture and electrolysis. Constructing a cost-effective and versatile macroscopic model simulation is critical for the industrial application of OFC. This study employs CFD-DDPM to obtain fluid dynamics parameters and couples heat and mass transfer models to construct macroscopic model of OFC based on a fluidized bed. Through calculations of OFC using both the macroscopic model and CFD-DDPM, molar fractions of O2, CO2, NO, and SO2 under various combustion conditions were found consistent with experimental measurements. Predictions under Recirculated Flue Gas (RFG) conditions showed comparable O2 and CO2 molar fractions at 30 % O2 & RFG, with the macroscopic model achieving 10.3 % and 69.3 %, versus 6.9 % and 72 % in CFD-DDPM. This demonstrates the ability of a macroscopic model to predict the design of the OFC in the fluidized bed. Importantly, the computational time of the macroscopic model is over 99 % shorter than that of CFD-DDPM. Consequently, employing a rapid simulation based on the macroscopic model method enables efficient simulation of OFC systems and facilitates the integration of oxygen combustion systems with other technologies like electrolysis. This approach provides valuable guidance for the development and application of OFC technology.