Explosion characteristics of bio-syngas at various fuel compositions and dilutions in a confined vessel

Safety issues for production, transportation, storage, and usage of bio-syngas persist due to the variability of bio-syngas composition. Therefore, this study focuses on the effects of fuel composition variation (H-2/CO/CH4) and diluents (N-2/CO2) on the explosion characteristics of bio-syngas/air mixtures in a constant volume combustion vessel. The experimentally determined explosion parameters were obtained at an initial temperature of 303 K, equivalence ratios of 0.6-1.5 and atmospheric pressure with a wide range of H-2/CO/CH4 compositions and dilution ratios. The results show that the concentration of H-2 or CH4 in the fuel mixture has a great influence on the explosion characteristics of bio-syngas/air mixtures, while the concentration of CO in the fuel mixture plays a mild role in affecting the explosion behaviors. Moreover, it is observed that the addition of N-2/CO2 to the fuel mixture can significantly reduce the potential of explosion hazards of bio-syngas/air mixtures, and CO2 dilution has stronger suppression effect on the explosion characteristics due to its larger negative influence on the thermal effect and chemical effect in comparison to that of N-2 dilution. The corresponding correlations of P-max/P-0 = f(Z(dilution)), t(c) = f(Z(dilution)), and (dP/dt)max = f(Z(dilution)) were found for predicting the explosion behaviors of N-2/CO2 diluted bio-syngas/air mixture at various dilution ratios.