Study On The Effects Of The Interactions Between The Biomass Three Components On Their Mixtures Combustion Under High Heating Rate

Biomass energy is a clean energy with large reserves,renewability,and zero CO₂emissions.At present,the biomass combustion for power generation is one of the main applications of biomass energy.Cellulose,hemicellulose,and lignin are the main components of biomass.Multiple studies on the interactions of the biomass three components and their effects on the biomass combustion were conducted under the condition of thermogravimetry（low heating rate）,but less under high heating rate.In this study,Hencken flat-flame burner,high-speed camera and the radiant energy temperature measurement technology were used to study the combustion process and characteristic combustion index of the biomass three components and their mixtures.The combustion behaviors and characteristic combustion indexes of the pure biomass three components were compared with those of their mixtures,and the influence of interactions between the biomass three components on the combustion of the mixtures under high heating rate was studied.First,the samples of the three components with a diameter of 5 mm and a mass of0.045 g were preparation and burning on a Hencken flat burner.The results showed that the ignition of three components were all homogeneous.Among the three components of biomass,the ignition delay time of lignin is the shortest（2.08s）,followed by hemicellulose（4.16s）,and that of cellulose is the longest（7.52s）.Lignin char was the easiest to ignite,followed by hemicellulose,and cellulose char was the most difficult to ignite.After the ignition of the cellulose and hemicellulose chars,the combustion temperature of the particles would increase sharply,while after the ignition of the lignin char,the temperature of the particles increased at a certain rate,but lower than that of cellulose and hemicellulose.Moreover,the combustion behaviours and interactions of nine kinds of mixtures of three compenents mixed in pairs under the blending ratio of 25%,50%,and 75%were studied.Also,the blends mixed of three components equally was studied.Comparing the combustion behaviors and characteristic combustion indexes of the pure biomass three components with those of their mixtures,it was found that the interactions between the biomass three components during pyrolysis had no obvious effect on the homogeneous ignition of the mixtures.The interaction between the three components in the process of char formation mainly influence the ignition of the blends chars,and was closely related to the blending ratio.The inhibitory effect of hemicellulose on the cellulose char formation significantly inhibited the char ignition of the 25%hemicellulose/75%cellulose blend.Cellulose and lignin can inhibit each other from forming char,and this interaction obviously inhibits the char formation of the 50%cellulose/50%lignin blend.The interaction between hemicellulose and lignin during the char formation process significantly inhibited the ignition of the 25% hemicellulose/75% lignin blend char.