Characteristics of Biogas and Syngas Combustion

Abstract

Biomass, one of the autonomous sectors of renewable energy, is characterized by its neutrality in CO2emissions during its life cycle and by a low content of nitrogen and sulfur which results in low emissions of NOx and SO2. This paper reports some numerical results of characteristics of biogas and syngas flames. Numerical calculations are performed using the COSILAB code for one-dimensional premixed flames. Three cases of flames are analyzed: CH4-air, biogas (CO2-CH4-air) and syngas (CO-H2-air and CO-H2-CO2-air). Calculations include laminar flame velocity, flame temperature and CO-NOx emissions with different parameters, such as temperature and pressure of fresh gases, equivalence ratio and gas composition. Several reaction mechanisms as GRI-Mech3.0, GRI Skeletal, San Diego, NIU GALWAY, CRECK Group, S. Davis et al. are used and compared to the results from the literature. Results show that calculations with some these mechanisms reproduce well experimental results of the literature. Results of biogas flames show that CO2addition induces a decrease in laminar burning velocity, an increase in CO emissions and a decrease in NOx formation. Calculations of syngas flames show that the hydrogen increase leads to an increase of laminar burning velocity and flame temperature.