TG-FTIR Experimental Study On Pyrolysis Of Lignin

Lignin is a major component of woody biomass and a renewable energy source,and has the advantage of abundant and quick regeneration speed. But its complexchemical structure and high thermal stability, it has not been effective in thedevelopment of its utilization. Thermogravimetric analysis-Fourier transform infraredspectromerer (TG-FTIR) was applied to analysis the thermogravimetric and main gasproducts of alkali lignin pyrolysis，combined with infrared spectroscopy study of thechars from lignin pyrolysis generated different stages. Thus the relationship of thefunctional groups and the gas phase product is speculated. The heating rate, celluloseblending ratio and alkali metal salts were studied in the lignin pyrolysis process andthe influence of gaseous product.DTG curves of lignin pyrolysis process has two obvious weightlessness peak.Lignin pyrolysis process rises to900℃within the weightlessness rate was53%. Inthe infrared spectra of products in the gas phase, it found that the main gaseousproducts of lignin pyrolysis were CO, CO2, CH4, and some organic carbohydrates.CO2precipitation peaks were low-temperature (250~450℃) and high temperature(650~750℃). It can be seen that unconjugated C=O functional groups with relativelyhigh activity are generated from the rupture of ether bond C-O. Generally, COoriginates from the rupture of ether bridges at low temperature350~450℃, while athigh temperature the dissociation of diaryl ether is the main source of CO production.CH4formed is mainly generated from the rupture of methoxy groups, while thesecond peak is caused by the rupture of methylene in the side chain or the furthercracking of volatiles.Through the study of the working condition of lignin pyrolysis process，theheating rate，the blend ratio of cellulose and loaded alkali metal salts was studied howto influence lignin pyrolysis processes．The results show that:with the increasing of heating rate，the DTG curves of volatility phase become wider，the onset temperatureand the maximum weight peak temperature move to the higher temperature side．Theslow heating rate is of great benefit to gas products．The Na，Ca and K salts additivehave a promoting effect on the formation of char，but they get the less CO and CO2formation in entire temperature range． The mutual inhibition occurs in theco-pyrolysis process at relatively low (<50%)of cellulose content，and with theincreasing of blend ratio the two mutually exhibit synergistic effects．It is found thatthe addition of cellulose promotes the formation of CO and CO2product at lowertemperature and restrain CH4product．...