The effect of torrefaction on the thermo‐kinetics of thermally processed black pine

Abstract

This paper investigates the kinetic behaviour of thermal decomposition of pretreated pine needles. The model-free methods of Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Kissinger, are used to determine the kinetic parameters of the processed pine needles. For a comparative analysis, the kinetic characteristic of the pre-treated pine needles is equated to the thermal decomposition of the raw pine needles. For torrefaction of the raw substrate, some changes related to the design have been made to the furnace. The raw material has been thermally pre-treated at a temperature of 523 K for 5 minutes. The volumetric rate of nitrogen during the torrefaction process is 42 L Á min −1 , while the purge flow rate of nitrogen gas is 0.2 L Á min −1 for the thermogravimetric analysis. The temperature range for the thermal degradation of the torrefied pine needles is 308 K-873 K. The activation energies determined by the FWO and the KAS methods are 157.08 kJ Á mol −1 and 160.54 kJ Á mol −1 , respectively, whereas it is 137 kJ Á mol −1 by the Kissinger method. The activation energy computed by the FWO and the KAS schemes for the raw material is found to be 1.3% less than that of the processed pine needles. The aromaticity of the thermally processed pine needles is increased by 13.61%. Thermal immunity or stability due to the increasing fraction of lignin causes the activation energy and frequency factor of the pre-treated pine needles to slightly elevate. The redistribution of the pyrolysis stages has been observed for the torrefied pine needle sample, the temperature scale at a constant heating rate increases slightly by 0.34% during the char formation.

Thermo‐economic assessment of a bench‐scale pyrolysis unit through a process simulator

“…The conversion percentage was invoked from the experimental work. The Arrhenius constant ( A ) and the activation energies ( E a ) of both forest waste and hog fuel were deduced from the Ozwa–Flynn–Wall (OFW), Kissinger–Akahira–Sunose (KAS) and Kissinger methods 38,39 . The equation of state applied to determine the fluid behavior was the Soave–Redlich–Kwong.…”

“…The Arrhenius constant (A) and the activation energies (E a ) of both forest waste and hog fuel were deduced from the Ozwa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS) and Kissinger methods. 38,39 The equation of state applied to determine the fluid behavior was the Soave-Redlich-Kwong. The power supply to operate the reactor was assumed to be 0.48 kW, whereas the geometric details were obtained by examining the metrology of the physical reactor (Fig.…”

Thermokinetic study of macadamia carpel pyrolysis using thermogravimetric analysis

“…The isoconversional models based on Equation ( 7) and the Arrhenius relationship require no knowledge of reaction models beforehand, being referred to as model-free methods. [44] Thus, the kinetic parameters were calculated from the slope of different linear model plots using the TGA data, from room temperature to 1273.15 K. [45] The isoconversional models used in this study were Ozawa, [23] Kissinger-Akahira-Sunose (KAS), [46] modified Starink, [47] and Kissinger. [48] Their respective equations are shown in Table 2, where β is the heating rate (K Á min À1 ), Ea is the activation energy (J Á mol À1 ), R is the universal gas constant (8.314 J K À1 mol À1 ), / is the conversion, and A is the pre-exponential factor (s À1 ).…”

Torrefaction of Willow in Batch Reactor and Co-Firing of Torrefied Willow with Coal

“…These three biomass fractions exhibit different thermal resistance. Consequently, the mass loss curves during wood biomass torrefaction reveal three distinct zones: the hemicellulose and cellulose decomposition zone between 200 and 300 • C and the gradually increasing lignin decomposition zone spanning 300 to 500 • C [16]. The research primarily focuses on the first zone, which pertains to the distribution of hemicellulose within a relatively low-temperature range of 225 to 300 • C. This process is commonly referred to as torrefaction and is used for roasting coffee beans.…”