Independent parallel pyrolysis kinetics of cellulose, hemicelluloses and lignin at various heating rates analyzed by evolutionary computation

2020 ◽  
Vol 221 ◽  
pp. 113165 ◽  
Author(s):  
Wei-Hsin Chen ◽  
Chun Fong Eng ◽  
Yu-Ying Lin ◽  
Quang-Vu Bach
Keyword(s):  
Evolutionary Computation ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Kinetics Of

Study on the Pyrolysis Kinetics of HCl-Pretreated Soybean Stalk

2014 ◽  
Vol 953-954 ◽  
pp. 261-266
Author(s):  
Dong Yu Chen ◽  
Yan Qing Hu ◽  
Qing Yu Liu
Keyword(s):  
Heating Rate ◽  
Temperature Increase ◽  
Loss Rate ◽  
High Efficiency ◽  
Three Dimensional ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Acid Washing ◽  
Shoulder Peak ◽  
Kinetics Of

To study the influences of the acid-washing on the characteristics of soybean stalk pyrolysis , and search the high-efficiency catalyst for biomass pyrolysis, pyrolysis experiments of soybean stalk pretreated by 0.1mol/L HCl acid solution were performed by nonisothermal thermogravimetric analysis (TGA) at five different heating rates. The results showed the pyrolysis process of HCl-washed soybean stalk can be separated into four stages (water loss, depolymeri-zation and vitrification, thermal decomposition, and carbonization). At the same heating rate, the maximum pyrolysis rate of HCl-washed is larger than untreated soybean stalk, but the corresponding temperature is higher. All the DTG (differential thermogravimetric) curveas appear a smaller shoulder peak respectively. With the heating rate increasing, the main pyrolysis zone of the TG (thermogravimetric) and DTG curves move to the high-temperature direction, and the maximum pyrolysis rate and its corresponding temperature increase too. HCl-wahsed makes the weight loss rate of the final temperature increase 5% approximately. The value area of activation energy of the main pyrolysis area is 140.19~174.59 kJ/mol calculated by the method of Ozawa. The Šatava method inferred the most possible mechanism function of HCl-wahsed soybean stalk is Zhuralev-Lesakin-Tempelman equation, which is three-dimensional diffusion.

Pyrolysis of Sugarcane Bagasse: A Consecutive Reactions Kinetic Model from TGA Experiments

2010 ◽  
Vol 660-661 ◽  
pp. 593-598 ◽  
Author(s):  
Kássia Graciele dos Santos ◽  
Taisa S. Lira ◽  
Valéria V. Murata ◽  
Marco Gianesella ◽  
Marcos A.S. Barrozo
Keyword(s):  
Kinetic Model ◽  
Sugarcane Bagasse ◽  
Room Temperature ◽  
Linear Method ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Exponential Factor ◽  
Consecutive Reactions ◽  
Kinetics Of ◽  
Good Agreement

The pyrolysis kinetics of sugarcane bagasse in nitrogen flow was studied by thermogravimetric analysis from room temperature to 1173 K at different heating rates (1.5, 3, 5, 10, 15, 20, 30 and 50 K/min). As there are three distinct devolatilization peaks in the DTG curve, each peak was associated to thermal decomposition of an individual biomass subcomponent (hemicellulose, cellulose and lignin). The kinetic model adopted was a consecutive reactions model. The kinetic parameters of the pyrolysis process, such as activation energy and pre-exponential factor, were calculated by least squares non-linear method and Scilab are used as the simulation tool. The simulated results showed a good agreement with the experimental data and the parameters found are similar to reported by the literature.

scholarly journals Flash Pyrolysis Kinetics of Extracted Lignocellulosic Biomass Components

2021 ◽  
Vol 9 ◽  
Author(s):  
Stefan Pielsticker ◽  
Benjamin Gövert ◽  
Kentaro Umeki ◽  
Reinhold Kneer
Keyword(s):  
Heating Rate ◽  
Molecular Structures ◽  
Small Scale ◽  
Drop Tube ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Flash Pyrolysis ◽  
Step Model ◽  
The Individual ◽  
Kinetics Of

Biomass is a complex material mainly composed of the three lignocellulosic components: cellulose, hemicellulose and lignin. The different molecular structures of the individual components result in various decomposition mechanisms during the pyrolysis process. To understand the underlying reactions in more detail, the individual components can be extracted from the biomass and can then be investigated separately. In this work, the pyrolysis kinetics of extracted and purified cellulose, hemicellulose and lignin are examined experimentally in a small-scale fluidized bed reactor (FBR) under N2 pyrolysis conditions. The FBR provides high particle heating rates (approx. 104 K/s) at medium temperatures (573–973 K) with unlimited reaction time and thus complements typically used thermogravimetric analyzers (TGA, low heating rate) and drop tube reactors (high temperature and heating rate). Based on the time-dependent gas concentrations of 22 species, the release rates of these species as well as the overall rate of volatiles released are calculated. A single first-order (SFOR) reaction model and a 2-step model combined with Arrhenius kinetics are calibrated for all three components individually. Considering FBR and additional TGA experiments, different reaction regimes with different activation energies could be identified. By using dimensionless pyrolysis numbers, limits due to reaction kinetics and heat transfer could be determined. The evaluation of the overall model performance revealed model predictions within the ±2σ standard deviation band for cellulose and hemicellulose. For lignin, only the 2-step model gave satisfying results. Modifications to the SFOR model (yield restriction to primary pyrolysis peak or the assumption of distributed reactivity) were found to be promising approaches for the description of flash pyrolysis behavior, which will be further investigated in the future.

Thermogravimetric Analysis of KCl-Pretreated Soybean Stalk

2015 ◽  
Vol 1092-1093 ◽  
pp. 118-121
Author(s):  
Dong Yu Chen ◽  
Qing Yu Liu
Keyword(s):  
Activation Energy ◽  
Thermogravimetric Analysis ◽  
Metal Salts ◽  
Pyrolysis Kinetics ◽  
Ozawa Method ◽  
Heating Rates ◽  
Energy Value ◽  
Lower Activation ◽  
Higher Temperature ◽  
Kinetics Of

To study the influence of KCl pretreating on the pyrolysis kinetics of soybean stalk, the pyrolysis of soybean stalk pretreated by different concentration KCl solutions were performed by nonisothermal thermogravimetric analysis (TGA) at five different heating rates. The Ozawa method was employed to calculate the activation energy. The results showed that the pyrolysis process of the soybean stalk pretreated by 3% and 10% KCl solution can be separated into four stages (water loss, depolymerization and vitrification, thermal decomposition, and carbonization). With the heating rate increasing, the main pyrolysis zone of the TG (thermogravimetric) and DTG curves move to the higher temperature region, and the maximum pyrolysis rate and its corresponding temperature increase too. A small amount of metal salts addition is conducive to the formation of volatile, and a certain amount of metal salts can improve the charcoal yield. More KCl additive makes the lower activation energy value, and the obtained activation energy value increases with the reaction degree.

Pyrolysis kinetics of potassium-impregnated rubberwood analyzed by evolutionary computation

2021 ◽  
Vol 319 ◽  
pp. 124145
Author(s):  
Yu-Ying Lin ◽  
Wei-Hsin Chen ◽  
Baptiste Colin ◽  
Bo-Jhih Lin ◽  
François Leconte ◽  
...  
Keyword(s):  
Evolutionary Computation ◽  
Pyrolysis Kinetics ◽  
Kinetics Of

Thermogravimetric Analysis and Pyrolysis Kinetics of Tannery Wastes in an Inert Atmosphere

2020 ◽  
Vol 115 (4) ◽  
pp. 123-131
Author(s):  
Lan Luo ◽  
Cheng-Kung Liiu ◽  
Eleanor Brown ◽  
Fang Wang ◽  
Yadi Hu ◽  
...  
Keyword(s):  
Reaction Model ◽  
Inert Atmosphere ◽  
Single Step ◽  
Industrial Wastes ◽  
Future Application ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Renewable Chemicals ◽  
Tannery Wastes ◽  
Kinetics Of

Industrial wastes generated from tanneries contain large quantities of water-insoluble proteins, which may be used for the production of composite materials, renewable chemicals and energy. In this work, the pyrolysis kinetics of powdered sheep fur wastes (SFW) was studied by thermogravimetry (TG) at different heating rates from room temperature to 600°C in nitrogen atmosphere. TG results revealed that there are three stages in this process. The overall apparent activation energy (E) in the main pyrolysis stage was determined to be 275.6 kJ mol-1 by modified Kissinger-Akahira-Sunose (MKAS) method. Because the pyrolysis of SFW could not be described by a single-step reaction, the experimental DTG curve of SFW was deconvoluted into three individual peaks followed by reconstruction of TG curves corresponding to three pseudo components. The average values of E obtained for these pseudo components are 234.7 kJ mol-1, 176.4 kJ mol-1, and 186.2 kJ mol-1, respectively. Generalized master-plots method indicated that the SFW pyrolysis may follow the random nucleation and growth mechanism (Avrami-Erofeev model). Reaction model functions f(?) for these pseudo components could be expressed as: f(?)=3.1(1-?)[-ln(1-?)]0.67; f(?)=3.6(1-?)[-ln(1-?)]0.72, and  f(?)=3.9(1-?)[-ln(1-?)]0.74, respectively. These results may provide insight for further studies as well as for future application of pyrolysis technology for tannery wastes. 

Pyrolysis Kinetics Equation of Larch Bark

2013 ◽  
Vol 772 ◽  
pp. 313-318
Author(s):  
Hong Shuang Du ◽  
Xiang Yu Li ◽  
Xue Yong Ren ◽  
Yan Xue Han
Keyword(s):  
Mass Loss ◽  
Mass Loss Rate ◽  
Kinetic Equations ◽  
Nitrogen Atmosphere ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Linear Temperature ◽  
Exponential Factor ◽  
Kinetics Of ◽  
Pyrolysis Kinetic

The larch bark was examined by non-isothermal means to determine the mass loss kinetics of the thermal decomposition with linear temperature programming in nitrogen atmosphere. In this work, mechanism equation of = was used forCoats-Redfern integral methodat the different heating rates. The apparent activation energy, pre-exponential factor and the pyrolysis kinetic equations at the different heating rates were obtained. The pyrolysis temperature area was divided into two separate temperature regions for the pyrolysis kinetic equation and the two components were decomposed respectively at the two separate temperature regions. The global mass loss rate of the bark is considered as controlled respectively by the reactions of the two components respectively during the lower and higher temperature ranges. The kinetics of the two components are found to abide by the mechanism equation of =, which gave the best fits to the experimental data. The obtained kinetic equations of the bark at the different heating rates were additionally validated by the reasonable agreement between the experimental and calculated results.

scholarly journals Thermogravimetric Kinetics of Selected Energy Crops Pyrolysis

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3977
Author(s):  
Magdalena Matusiak ◽  
Radosław Ślęzak ◽  
Stanisław Ledakowicz
Keyword(s):  
Activation Energy ◽  
Energy Crops ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Exponential Factor ◽  
Miscanthus Giganteus ◽  
Temperature Ranges ◽  
The Given ◽  
Kinetics Of ◽  
Derivative Thermogravimetry

The main purpose of this paper was to compare the pyrolysis kinetics of three types of energy crops: Miscanthus giganteus, Sida hermaphrodita, and Sorghum Moench. Studies were conducted in thermobalance. Feedstock samples were heated up from ambient temperature to 600 °C under an inert argon atmosphere. Three heating rates of β = 5, 10, and 20 °C/min were applied. Reactions occurring in the given temperature ranges were grouped together into so-called lumps identified by the deconvolution of derivative thermogravimetry (DTG) curves that corresponded to biomass compositions (hemicellulose, cellulose, and lignin). For the estimation of the activation energy and pre-exponential factor, the Friedman and Ozawa–Flynn–Wall methods were used. The final kinetic parameters were determined by nonlinear regression assuming that thermal decomposition proceeded via three parallel independent reactions of the nth order. The activation energy of hemicellulose, cellulose and lignin was determined to be in the range of 92.9–97.7, 190.1–192.5, and 170–175.2 kJ/mol, respectively. The reaction order was in the range of 3.35–3.99 for hemicellulose, 1.38–1.93 for cellulose, and 3.97–3.99 for lignin. The obtained results allow us to estimate the pyrolytic potential of energy crops selected for this study, and can be used in designing efficient pyrolizers for these materials.

Pyrolysis Kinetics of Oil Shale and its Kerogen

2015 ◽  
Vol 733 ◽  
pp. 236-240 ◽  
Author(s):  
Wei Wang ◽  
Shu Yuan Li ◽  
Ting Tan ◽  
Yue Ma
Keyword(s):  
Oil Shale ◽  
Regression Coefficient ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Nitrogen Flux ◽  
Thermo Gravimetric ◽  
Gravimetric Data ◽  
Kinetics Of

The pyrolysis kinetics of Chinese oil shale and its kerogen was investigated using thermo gravimetric analysis (TGA) in this paper. Experiments were performed at four different heating rates of 10, 15, 20 and 25°C/min from ambient temperature to 560 °C at nitrogen flux with 60ml/min. The results demonstrated that the thermal decomposition of oil shale and its kerogen involved three degradation steps. Different thermo gravimetric data were analyzed by Friedman procedure. The values of apparent activation energy E of oil shale ranged from 160kJ/ mol to 240kJ/mol, but these of kerogen were in the range of 150kJ/mol to 240kJ/mol. It was found that the plot of lnA versus E became a linear line with a regression coefficient of 0.99.

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