Study On Pyrolysis Of Sulfate

Lignin is a kind of energy material with great potentia ity.The degradation for preparation of low molecule chemical materials from lignin is one of the efficient utilization ways.Eucalyptus and bambusa intermedia sulphate lignin were separated from their black liquor of sulfate cooking pulping with acid precipitation method.1. The data of chemical composition analysis show that the contents of total lignin (including Klason lignin and acid soluble lignin) in eucalyptus and bambusa intermedia sulphate lignin are high, and the total contents are97.58%,90.14%respectively. And the contents of impurities such as carbohydrates, ash content are very low. These eucalyptus and bambusa intermedia sulphate lignin meet the requirement of subsequent degradation reaction.2. The results of thermogravimetric analysis from eucalyptus and bambusa intermedia sulphate lignin show that the main pyrolysis temperature range is in300-600℃,and the quality of eucalyptus sulphate lignin changed96%,and bambusa intermedia sulphate lignin92%in this temperature range. The results of Py-GC/MS show that the lignin degradate mainly in sulfate lignin macromolecule side chain,and the total percentage of aliphatic compounds in eucalyptus and bambusa intermedia sulphate lignin degradation products are54.43%,41.70%respectively. Partial ether bond in benzene ring has not been cleavaged, and there are a large number of benzene compounds with methoxyl group in the degradation products.3. These ulphate lignin were degraded by low temperature hydrothermal method and those degradation products were separated. Within the same time of degradation, with the increase of temperature, the yields of oil1gradually increases while the yields of oil2, oil3and total oil gradually reduces. At the same temperature, with the addition of the degradation time, the yields of oil1and gases increases, the yields of oil3and total oil decreases. After the degradation, the relative molecular mass of oil1and oil2are between300and400, and the relative molecular mass of oil3are between1100and1200. The infrared data of residue products show that ether bond in side chain is degraded obviously, but fragrant ether bond is not fractured, and benzene is not degraded largely.4. The GC/MS analysis show that there are a lot of aromatic ring compounds in the degradation productions, which is the characteristic compound of lignin, including phenol, phenyl aldehyde, phenyl ketone and benzene ester compounds. There are a large number of methoxyl group in the structure of degradation compounds with benzene ring. The largest contents of products are dibutyl hydroxy toluene and aromatic esters.