Characterization of Biogas-Syngas Turbulent MILD Combustion in the Jet in Hot Co-Flow Burner

Moderate or Intense Low-oxygen Diluted (MILD) combustion is a promising technology with interesting properties such as high efficiency and zero-emission. The biogas-syngas mixture is also considered a promising new renewable biofuel with low emissions. This work aims to examine the effects of several parameters on the biogas-syngas flame structure and emissions under MILD conditions in the Jet in Hot Co flow (JHC) burner. The turbulence is modeled by the modified standard k-epsilon model; whereas combustion-turbulence interaction is handled by the Eddy Dissipation Concept (EDC) in conjunction with three detailed reaction mechanisms, namely: GRI-Mech 3.0, GRI-Mech 2.11, and DRM 2.11. Effects of biogas-syngas composition, temperature, and oxygen concentration in the hot co-flow and Reynolds number of the fuel jet have been elucidated. Results show that flame structure is more sensitive to the increase of hydrogen in syngas than that of methane in biogas. An increase of oxygen concentration or temperature in the co-flow stream leads to more NO formation whereas Reynolds number augmentation reduced them. Furthermore, NO species production is globally governed by the NNH route.

Automated summary

The study examines the effects of biogas-syngas mixture on flame structure and emissions under MILD conditions, revealing that flame structure is more sensitive to hydrogen content in the syngas. Additionally, an increase in oxygen concentration or temperature in the hot co-flow stream leads to more NO formation, while an increase in Reynolds number reduces NO emissions.