Comparative Thermal Degradation Behaviors and Kinetic Mechanisms of Typical Hardwood and Softwood in Oxygenous Atmosphere

Abstract

In order to utilize woody biomass effectively for bioenergy and chemical feedstocks, the comparative thermal degradation behaviors and kinetic mechanisms of typical hardwood (beech wood) and softwood (camphorwood) were studied at various heating rates in air. The Kissinger-Akahira-Sunose approach combined with the Coats-Redfern approach was employed to estimate the kinetic triplet. Softwood degradation began and ended at lower temperatures than hardwood. Compared with softwood, the maximal reaction rate of hardwood was greater and occurred in the higher temperature region. Two decomposition regions were determined by the variation of activation energy, and the dividing point was α = 0.6 and α = 0.65 for hardwood and softwood, respectively. Moreover, the average activation energy of hardwood was larger than that of softwood during the whole decomposition process. The thermal degradation process occurring in region 1 was dominated by the Avrami-Erofeev and 3D diffusion models for hardwood and softwood, respectively. Furthermore, the kinetic modeling results showed good consistency between the experimental and simulated curves under 5, 15, 20, and 40 K/min. It is noted that the thermogravimetric experimental profile under 20 K/min was not used for estimating the kinetic triplet. Besides, the combustion performance of hardwood is superior to softwood under the same external conditions (heating rate and atmosphere).

Kinetic study of mechanical and thermal properties and thermal degradation of PVC composites based on coal gasification fine slag

“…In particular, E is the energy barrier that allows one to define the chemical reaction to be overcome as well as its feasibility. 43,44 It has been shown that the reaction proceeds more efficiently at lower activation energies. Figures 7-9 display the iso-conversion diagrams obtained at different heating rates, from which the instantaneous value of E at different conversion rates can be calculated from the individual slopes according to the linear regression equations.…”

Measurement of the Kinetics and Thermodynamics of the Thermal Degradation for a Flame Retardant Polyurethane-Based Aerogel

“…The heating rate increases to a higher rate and then gradually decreases to the set heating rate, so an exponential decaying trigonometric function (shown in Equation ( 19)) was used to fit the experimental heating program. First, the actual heating rate curve at 10 K min −1 was fitted using Equation (19). The same fitting exercise was performed for the data obtained at heating rates of 5 K min −1 and 20 K min −1 .…”

“…The characterization of material flammability frequently relied on a thermogravimetric analysis (TGA) experiment [17][18][19] and these are the most common technique used in such measurements. A milligram-size sample and relatively slow heating rates were adopted in these experiments, and thus the heat and mass transport inside the sample was assumed to be negligible.…”

Electrocatalytic conversion of G-type and S-type phenolic compounds from different tree species in a heteropolyacid fluidized system

“…Electrocatalytic conversion of G-type and S-type phenolic compounds from different tree species in a heteropolyacid fluidized system 5 [40], camphorwood [41], and Cunninghamia lanceolata [42]. S-type phenolic compounds are originated from hardwood tree species, e.g., poplar [43], beech [44],…”