Characterization of premixed laminar flow combustion with hydrogen doping of the associated gases

Abstract

Hydrogen doping in associated gas combustion presents a promising strategy for mitigating carbon emissions from typically flared or vented gases. To support this idea, this study employed Chemkin Pro to model the laminar premixed combustion of associated gases and conducted a sensitivity analysis of key combustion factors. The results demonstrated that increasing the hydrogen-doping ratio accelerated flame propagation and reduced combustion product accumulation time, while also elevating flame instability and inducing cracks or folds on the flame front at higher ratios. Notably, flame speed exhibited a 40 % increase per 10 % rise in the hydrogen-doping ratio, which directly enhanced combustion efficiency. Flame temperature peaked at an equivalence ratio of 1, whereas flame speed enhancement was maximized at a ratio of 1.3. Higher premix temperatures increased flame speed, and elevated combustion pressures raised flame temperature (stabilizing above 1 atm), with flame speed peaking at 0.06 atm. Critically, hydrogen doping below 15 % minimally altered flame morphology, but 30 % doping caused significant flame retraction toward the nozzle, which increased the flashback risk and raised NOx emissions by nearly one third. These findings provide insights for optimizing hydrogen-doped combustion processes to balance efficiency gains while ensuring operational safety and emission control.

Keywords

• Associated gas
• Laminar premixed combustion
• Hydrogen
• Flame characteristics
• Sensitivity analysis