Thermogravimetric Studies on Non-isothermal Oxidative Pyrolysis of Lignoceilulosic Materials

摘要

Inter species variations of lignoceilulosic fibres were investigated in terms of the thermal degradation behaviour of ten different bamboo species using simultaneous TG-DTA analysis. The pyrolysis profiles under oxidative atmosphere shows that the thermal stability based on first stage of degradation is lowest for bambusa vulgaris and higher stability is attributed to dendrocalamus strictus and dendrocalamus membranaceus. The threshold temperature for active biomass pyrolysis for the first mass loss stage is between 220°C - 240°C. Dendrocalamus membranaceus, Bambusa nutans and Bambusa vulgaris complete the decomposition process in two distinct stages and all others in three stages. The first stage, dominant below 340°C, degrades polymeric chains forming active carbonaceous char which release volatile gases upon increase in temperature and -5% by weight of char remains above 450°C. The kinetic parameters of the solid state reactions were calculated using the Coats-Redfern integral method and are found to be highest for Bambusa vulgaris. The activation energy for the major mass loss stage in decomposition profiles ranges from 153.0 to 226.9 kJ mor1.The stability in terms of DTG peak temperature is highest for dendrocalamus strictus, which possess the lowest values for kinetic parameters for the main decomposition stage. For the second stage, values of the kinetic parameters are found to be maximum for Bambusa vulgaris and the lowest for Bambusa nutans. Solid state kinetics were found to obey Mampel equation comprising the mechanism of random nucleation with single nucleus on each particle.