Computational analysis on oxygen MILD combustion using synthesis gas

Abstract

In this paper, a possibility of the oxygen-syngas MILD combustion was assessed using the CFD analysis by applying the JHC (Jet-in Hot Co-flow) combustion system. The effect of the various syngas composition ratios was analyzed, and heating value of synthesis gas was controlled by ratio of CO and H2. The Ansys Fluent, commercial CFD code with RANS (Reynolds Averaged Navier-Stokes), modified k-ε equations and EDC (Eddy Dissipation Concept) model using 2D-axisymmetric computational domain was used in order to analyse oxygen-syngas MILD combustion. It was confirmed that the oxygen-syngas combustion can be formed in the MILD combustion under conditions of the oxygen concentration of 3 ~ 9 %, which is similar condition to the air-fuel MILD combustion region in the Adelaide and Delft flame. As the proportion of H2 in the composition of the synthesis gas is decreased, the region of the MILD combustion with Da < 1 is found to become wider due to the decrease in the Arrhenius reaction rate. At higher oxygen concentration in the co-flow, the region with Da <1 known as MILD regime tends to be decreased.