ユーカリ材黒液の濃縮, 燃焼性

第4報 ユーカリ材黒液の熱分解性

抄録

It is reported that the burning characteristics of concentrated eucalyptus black liquor is impaired by polyphenolic extractives. In an attempt to assess the burning properties of black liquors from E. calophylla, E. marginata and E. diversicolor of Western Australia, comparing with that from domestic hardwoods, vacuum dried black liquors were pyrolysed by a Shimazu Pyrolyser PYR-1A at 400°C in helium atmosphere to generate low molecular gases, such as CO₂, CO and methane, which were determined by a TCD gaschromatograph with active carbon columns at 150°C. It was found that eucalyptus black liquors volatilized more CO₂ and less CO and CH₄. However, there was no appreciable difference in gas volatilization between eucalyptus and hardwoods black liquors after removing inorganic components by dialysis.
The thermogravimetric analysis and the differential thermal analysis were carried out on eucalyptus black liquors in nitrogen at temperature rise of 5°C/min. by Agne TGD-1500 differential thermoanalyser. Generally, eucalyptus black liquor showed much less weight loss at pyrolysis above 300°C. A DTA curve of black liquor from E. calophylla had a distinct endothermic peak at 160-180°C, which was shifted to lower temperature and diminished by the previously mentioned partial wet combustion and preheating cooking.
Hemicellulose extracted from domestic hardwoods and various phenols, including ellaggic acid and kino were added to. hardwoods black liquor, which were investigated according to the above mentioned methods.
As a conclusion, it was, assumed that the poor burning properties of eucalyptus black liquor were caused by relatively inert thermal degradation with volatilization of comparatively more quantity of incombustible CO₂ and less CH₄ and CO, which are essential to burning, due to polyphenolic extractives.