Abstract
MILD oxy-fuel combustion is the next generation oxy-fuel combustion technology combined the advantages of MILD combustion and conventional oxy-fuel combustion. It features as increasing the furnace temperature uniformity, promoting the radiation heat transfer, and achieving near zero emissions for fossil fuels. An oxy-fuel MILD burner with central fuel jet and high momentum oxygen jets was simulated by Computational Fluid Dynamics (CFD) method, and a finite-rate/eddy-dissipation model (FR/EDM) with two-step irreversible propane and oxygen reaction was used as the combustion model. Different parameters of burner including the momentum ratio of the oxygen and fuel jets and the distance between oxygen and fuel jets were simulated to evaluate the influence of burner parameters on MILD oxy-fuel combustion characteristics such as flue gas velocity and temperature, species fields, internal flue gas recirculation ratio, and different turbulence and chemical timescales. Moreover, the oxidation mixture ratio and Damkohler number were used to character the chemical reaction zone structure and the microscopic characteristics of MILD oxy-fuel combustion. Finally the optimized burner parameters were preferable to guide the design and operation for MILD oxy-fuel combustion.
