Cellulose Pyrolysis Mechanism Research Based On The In Situ Infrared And PY-GC/MS

With the development of economic, the demand for energy is increasingly urgent。But the traditional fossil energy is limited with reserves, severe pollution and other issues, the development of new energy research is imminent.Biomass energy are recognized as the most likely to replace fossil energy cause its advantage,such as widely distributed, large reserves, renewable, low pollution to the environment。The research of biomass energy utilization has a great role to ease the global energy crisis and reduce the pollution.In this paper, in situ infrared(PY-FTIR) and pyrolysis- gas chromatograph-mass spectromete(PY-GC-MS) were used to analysis cellulose and its typical model compound(cellobiose, beta-D-pyran glucose) and intermediate(levglucosan, 5-HMF) pyrolysis experiments.It was found that the pyrolysis of cellulose and cellobiose varies with temperature are deepening, the kinds and quantity of small molecular products also increase.Thermal cracking of cellulose and cellobiose starting at about 360℃and 250℃. Cellulose depolymerization reactions happen first, then carried out in accordance with the law of monomer thermal cracking reaction, the existence of active cellulose was verified. Pyrolysis experiments of cellobiose indicate intermediate levglucosan secondary thermal cracking reaction, there has been a marked by inverse acetal ring-opening reaction, further 5-HMF generated from pyrolysis.At the same time, furfural occurred secondary thermal cracking produced furan directly.For beta-D-pyran glucose and levglucosan multi-loading pyrolysis experiments,, the pyrolysis products of levglucosan and beta-D-pyran glucose mainly were furans, pyrans and small molecules.The content of levglucosan, 5-HMF, furfural, CO2 presents different changing laws with pyrolysis time of beta-D-pyran glucose.In situ ftir analysis shows LG pyrolytic reaction mainly include:dehydration reaction to generate 2, 3 d-mannose, loop open and then dehydration to generate further furan type material, the appearance of small molecules in the late response.Beta-D-pyran glucose pyrolytic reaction mainly include:dehydration generated LG;loop open and dehydration cyclization, in turn, generate 5-HMF class material such as furfural, in addition to CO2 in a large number of other small molecules generated.Pyrolysis experiments of 5-hydroxymethyl furfural(5-HMF) were conducted and the product composition was detected by using a PY-GC-MS analyzer. The results show that nearly 86% of the pyrolysis product is furan ring-contained substance, and that a certain amount of small molecules exist in the product, which means that the pyrolysis process of 5-HMF is mainly a side-chain degradation process concomitantly with the fracture of furan rings. Moreover, the converting law of the product in the pyrolysis process was supervised in real time via in-situ FT-IR. The results show pyrolytic reaction mainly include:furan-2,5-dicarbaldehyde forms from two consecutive dehydrogenations and then converts into 5-methyl furfural after the dehydroxylation and hydrogenation of hydroxymethyl, the whole fracture of hydroxymethyl side chain and aldehyde group side chain leads to the formation of furfural and furfuryl alcohol, and 2-methylfuran may be produced via the secondary pyrolysis of furfural and furfuryl alcohol.