Experimental Study Of Biomass Mixture Pyrolysis Based On Components

With the increasingly serious energy crisis,biomass energy has been received the world,s attention.Biomass pyrolysis technology has attracted much attention since it is able to obtain gas,liquid and solid three-phase products.Lignocellulosic biomass is mainly composed of cellulose,hemicellulose and lignin.The different pyrolysis properties of the three components lead to that biomass pyrolysis is more complicated,while the partially overlapping pyrolysis temperature range and the same pyrolysis products make the three components have the effect of mutual coupling during the pyrolysis process.Based on these,the interaction between the three components of biomass was studied in this paper by thennogravimetric analyzer and Py-GC/MS respectively,using the alternative samples of cellulose,hemicellulose and lignin.Firstly,in order to clarifies the thennogravimetric process and the composition and distribution of pyrolysis products of the three components,the pyrolysis experiments of the three components were carried out respectively using two kinds of experimental instruments.The thermogravimetric results showed that the thermogravimetric rate of cellulose was the highest in the three components,the lignin was the smallest;the pyrolysis temperature range of lignin was the most extensive,the cellulose was the narrowest;the coke yield of lignin was the highest,and cellulose has the highest volatile yield;hemicellulose has the lowest initial pyrolysis temperature to it,s thermostability was worst.The results of GC/MS showed that the pyrolysis products of cellulose were mainly carbohydrates with levoglucan,and some low molecules such as acids and ketones;The main pyrolysis products of hemicellulose were some light products such as acids,ketones and aldehydes and other products,and the pyrolysis productions species of hemicellulose was most;while the pyrolysis productions species of lignin was least,and the main pyrolysis products of lignin were phenols with Guaiacol.Secondly,the three components of biomass were mixed in different proportions,and the interaction between the three components was studied by thermogravimetric analysis.The results showed that the interaction between cellulose and hemicellulose could inhibit the weight loss rate during the pyrolysis process of cellulose and increase the pyrolysis temperature range of cellulose,but it had no significant effect on the pyrolysis process of hemicellulose;when the content of lignin in the mixed sample is high,the interaction between hemicellulose and lignin could promote the weight loss rate of hemicellulose,but has no significant effect on lignin;the interaction between cellulose and lignin could decrease the weight loss rate of reaction of the cellulose,and as the lignin content of the mixed sample increases,the more pronounced decrease,and it also reduces the yield of the solid product in the mixed sample.Then the activation energy was calculated by C-R integral method,and the results of thermogravimetric experiment were verified.Finally,the effects of the interaction between the three components on the pyrolysis product and the yield of some products were investigated by Py-GC/MS.The results showed that the interaction between cellulose and hemicellulose inhibited the pyrolysis of cellulose and reduced the yield of levoglucan and increased the yield of hydroxybutanone;the presence of lignin did not inhibit the pyrolysis process of hemicellulose,and the interaction between hemicellulose and lignin increased the yield of some low molecular products of hemicellulose,such as hydroxybutanone,while the yield of guaiacol in lignin is reduced since the presence of hemicellulose;the interaction between cellulose and lignin promoted the yield of low molecule products,but inhibited the yield of levoglucosan and guaiacol.