Thermogravimetric studies on co-pyrolysis of raw/torrefied biomass and coal blends

2020 ◽  
Vol 38 (11) ◽  
pp. 1259-1268
Author(s):  
NL Panwar ◽  
Bhautik Gajera ◽  
Sudhir Jain ◽  
BL Salvi

The pyrolysis and co-pyrolysis behaviours of cotton stalk (CS), torrefied cotton stalk (TCS) and mined coal, as single fuels, and their blends, have been examined through thermogravimetric analysis. Biomass has been torrefied at 250°C for 45 min to enhance physicochemical properties, and then mixed with mined coal for co-pyrolysis. Thermal degradation of CS and TCS is characterized by a reaction. However, this is not the case for mined coal, which shows a single-stage reaction. The thermal degradation of all blends was done in three stages: dehydration; biomass and small mined coal; and lignin or mined coal. A similar trend emerged for mass loss of individual fuels, which depended mainly on their ratios in the blend. The kinetics of pyrolysis and co-pyrolysis of all fuels were calculated at 20°Cmin−1 heating rate using the Coats−Redfern model-fitting method.

2017 ◽  
Vol 30 (7) ◽  
pp. 787-793 ◽  
Author(s):  
Xu Su ◽  
Yong Xu ◽  
Linshuang Li ◽  
Chaoran Song

Two kinds of thermoplastic polyimides (PIs) were synthesized via a two-step method with 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 4,4′-oxydianiline (ODA) diamine, and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), and their thermal degradation kinetics was studied by thermogravimetric analysis at different heating rates under nitrogen. Derivative thermogravimetric analysis curves indicated a simple, single-stage degradation process in PI BTDA-BAPP and a two-stage degradation process in PI BTDA-ODA-BAPP. The activation energies ( Eas) of the thermal degradation reaction were determined by the Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose methods without a knowledge of the kinetic reaction mechanism. By comparing the values of Ea and weight loss temperatures, it was demonstrated that the thermal stability of PI BTDA-ODA-BAPP was superior to that of PI BTDA-BAPP.


2020 ◽  
Vol 15 (1) ◽  
pp. 253-263
Author(s):  
Sharmeela Matali ◽  
Norazah Abd Rahman ◽  
Siti Shawalliah Idris ◽  
Nurhafizah Yaacob

Torrefaction is a thermal conversion method extensively used for improving the properties of biomass. Usually this process is conducted within a temperature range of 200-300 °C under an inert atmosphere with residence time up to 60 minutes. This work aimed to study the kinetic of thermal degradation of oil palm frond pellet (OPFP) as solid biofuel for bioenergy production. The kinetics of OPFP during torrefaction was studied using frequently used iso-conversional model fitting (Coats-Redfern (CR)) and integral model-free (Kissinger-Akahira-Sunose (KAS)) methods in order to provide effective apparent activation energy as a function of conversion. The thermal degradation experiments were conducted at four heating rates of 5, 10, 15, and 20 °C/min in a thermogravimetric analyzer (TGA) under non-oxidative atmosphere. The results revealed that thermal decomposition kinetics of OPFP during torrefaction is significantly influenced by the severity of torrefaction temperature. Via Coats-Redfern method, torrefaction degradation reaction mechanism follows that of reaction order with n = 1. The activation energy values were 239.03 kJ/mol and 109.28 kJ/mol based on KAS and CR models, respectively. Copyright © 2020 BCREC Group. All rights reserved 


2021 ◽  
Vol 10 (4) ◽  
pp. 737-746
Author(s):  
Ukrit Samaksaman ◽  
Kanit Manatura

The co-combustion characteristics and kinetics of torrefied sugarcane bagasse (TB), lignite (L), and their blended samples were experimentally investigated using thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG)based on the Coats-Redfern method for kinetic estimation.Their physicochemical properties were also investigated.Raw bagasse was thermally treated in a laboratory-scale torrefactor at 275 °C with a torrefaction time of 60 min under an inert nitrogen environment.Then, the torrefied bagasse was blended with Thai lignite as a co-fuel at ratios of 50:50 (TB50L50), 70;30(TB70L30), and 90:10 (TB90L10), respectively. Torrefaction improved the fuel properties and heating value of the raw bagasse as well as reducing the O/C and H/C ratios.In addition, the blending of torrefied bagasse with lignite improved the combustion behavior.The TGA and DTG results indicated that the ignition and burnout temperatures stepped downwards with different increasing ratios of torrefied bagasse.The co-combustion behavior at the maximum burning rate showed that the burnout temperatures of TB50L50, TB70L30, and TB90L10 were 532, 529, and 528 °C, respectively, indicating a slight decrease with an increasing torrefied bagasse blending ratio.These results were sufficient to provide comprehensive guidelines in terms of the design and operation of the combustion system for adding torrefied bagasse into the co-firing process.


2010 ◽  
Vol 82 (4) ◽  
pp. 1284-1289 ◽  
Author(s):  
Chun-Yan Ou ◽  
Chao-Hua Zhang ◽  
Si-Dong Li ◽  
Lei Yang ◽  
Jing-Jing Dong ◽  
...  

2018 ◽  
Vol 39 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Dev K. Mandal ◽  
Haripada Bhunia ◽  
Pramod K. Bajpai

AbstractIn this article, the influence of polylactide and pro-oxidant on the thermal stability, degradation kinetics, and lifetime of polypropylene has been investigated using thermogravimetric analysis under nitrogen atmosphere at four different heating rates (i.e. 5, 10, 15, and 20°C/min). The kinetic parameters of degradation were studied over a temperature range of 30–550°C. The derivative thermogravimetric curves have indicated single stage and two stage degradation processes. The activation energy was evaluated by using the Kissinger, Kim-Park, and Flynn-Wall methods under the nitrogen atmosphere. The activation energy value of polypropylene was much higher than that of polylactide. Addition of polylactide and pro-oxidant in polypropylene decreased the activation energy. The lifetime of polypropylene has also decreased with the addition of polylactide and pro-oxidant.


2007 ◽  
Vol 5 (1) ◽  
pp. 341-348
Author(s):  
Tang Wanjun ◽  
Chen Donghua

AbstractThe kinetics of Li2SO4·H2O dehydration in static air atmosphere was studied on the basis of nonisothermal measurements by differential scanning calorimetry. Dehydration data were subjected to an integral composite procedure, which includes an isoconversional method, a master plots method and a model-fitting method. Avrami-Erofeev equation was found to describe all the experimental data in the range of conversion degrees from 0.1 to 0.9. The determined activation energy equals 65.45 kJ·mol−1 with standard deviation ±0.47 kJ·mol−1. The estimated value of parameter m in Avrami-Erofeev equation is 2.15 with standard deviation ±0.11. Also, the obtained pre-exponential factor is 7.79×105 s−1 with standard deviation ±0.55×105 s−1. The results show that the present integral composite procedure gives self-consistent kinetic parameters.


Sign in / Sign up

Export Citation Format

Share Document