Study Of Biomass Components Catallytic Pyrolysis And Indteractions During Pyrolysis

Biomass is the fourth abundant resource after coal,oil and nature gas,reasonable development and efficient utilization of biomass is of vital importance now.Catalytic pyrolysis of biomass is an important way of maximizing the utilization.Both zeolite catalysts and interactions between biomass components can influence the selectivity of bio-oil.So cellulose and lignin,the main components of biomass were chosen to do the research.The experiments of biomass components catalytic pyrolysis and the interactions during the process were carried out by TGA and Py-GC/MS.Finally,three model compounds of cellulose and lignin were chosen to have a further study of interactions between cellulose and lignin during catalytic pyrolysi.The weight loss curve of pyrolysis of cellulose and lignin reveals that: the pyrolysis reaction of cellulose occurs in a concentrated temperature range while the weight loss of lignin undergoes a wide temperature range,this is resulted from the different structures of cellulose and lignin.The four zeolite catalysts with different pore size show different influence in the pyrolysis of cellulose and lignin,H-beta favors the formation of coke and SAPO-34 promotes the formation of bio-oil and gas.Fast pyrolysis experiments of cellulose and lignin were implemented.The results shows that pyrolysis of lignin mainly produces phenols,guaiacols,syringols aromatics and catechol products.H-beta favors the formation of phenols,HZSM-5 promotes most of the main products and SAPO-34 inhibited the formation of aromatics while promoted others.Interactions between cellulose and lignin during catalytic and non-catalytic pyrolysis were existed since yield of char was increased and the maximum weight loss peak shifted to higher temperature region and the maximum weight loss rate decreased.Levoglucosan,the main product from cellulose pyrolysis,was decreased during catalytic and non-catalytic pyrolysis under the influence of lignin,but the presence of lignin can promote the formation of furfural when catalyzed by H-beta.Cellulose can improve the formation of phenol and guaiacol during non-catalytic pyrolysis of lignin,however,during catalytic pyrolysis,it showed an inhibition.Finally,a statistic methods were used to evaluate the interactions between cellulose and lignin during pyrolysis,and found the order of strength of interaction were H-beta>HZSM-5>SAPO-34,the non-catalytic pyrolysis interaction was between HZSM-5 and SAPO-34.It is indicated that H-beta and HZSM-5 catalysts can enhance the interactions between cellulose and lignin in mixed pyrolysis,while SAPO-34 can weaken the interactions.The mixed pyrolysis of model compounds of cellulose and lignin shows that cellulose can promote the demethoxylation and dehydroxylation of lignin during pyrolysis.Under catalytic conditions,the effect is more significant.Lignin influence the pyrolysis of cellulose by inhibiting the dehydration of cellulose macromolecules,promoting the formation of furan products after ring opening,and the lignin pyrolysis product can promote the secondary reaction of dehydrated saccharide products.Thereby,the furan and small molecule products are converted and it can inhibit further cleavage of the furan product.