Effect of composition of biomass steam-gasified gas on laminar burning velocity and overall activation energy

Abstract

Biomass steam-gasified gas (BGG-S), a mixture of H2/CO/CH4/CO2/C2H4/C2H6, is a promising fuel with appreciable lower heating value (12.9–13.7 MJ/Nm3). However, the composition of BGG-S is variable, which brings difficulties to burner design and combustion stability. The laminar burning velocity (SL,0) of BGG-S with variable composition was measured by an improved flat flame method, which can also measure the overall activation energy (Ea). The prediction of five detailed mechanisms was analysed and compared. Results show that the SL,0 of BGG-S varies monotonously with the equivalence ratio (φ), but the Ea has different variation characteristics. Ea has a minimum value when φ = 0.7–0.8 and a maximum value when φ = 1. The USC-Mech II mechanism is the most accurate for predicting SL,0, and the San Diego mechanism is the most accurate for Ea. Composition has a great impact on SL,0. Therefore, a comprehensive model was proposed to predict the SL,0 of BGG-S under variable composition and different φ. The composition has a significant impact on the combustion characteristics of BGG-S. It affects the coefficients of the quadratic function model between SL,0 and φ. The trend of Ea of BGG-S is affected by the multiple components.