Pyrolysis of mustard oil residue: A kinetic and thermodynamic study

Enhancing fuel characteristics and combustion performance of cellulose-rich straws through CO2-assisted torrefaction

Cellulose-rich straws of corn and rice were torrefied under carbon dioxide, and the fuel characteristics and combustion performance of the obtained biochar were investigated. A high severity resulted in surface collapse, greater pore volume, elimination of oxygen, elevated calorific value, and improved hydrophobicity in biochar. Following carbon dioxide torrefaction, the cellulose content in solid biochar experienced a slight decrease when the temperature was raised to 220 °C for longer residence durations. At 300 °C, the cellulose content in the biochar was nearly eliminated, while the relative proportion of non-sugar organic matter in corn stover and rice straw increased to 87.40 % and 77.27 %, respectively. The maximum calorific values for biochar from corn and rice straws were 22.38 ± 0.03 MJ/kg and 18.72 ± 0.05 MJ/kg. The comprehensive combustion indexes of rice and corn straw samples decreased to 1.06 × 10-7 and 1.31 × 10-7 after torrefaction at 300 °C, respectively. In addition, the initial decomposition temperatures increased by 38 °C and 45 °C, while the ultimate combustion temperatures rose by 13 °C and 16 °C for corn and rice straws, respectively. These results imply an extended combustion timeframe for the torrefied samples.

Thermogravimetric and thermo-kinetic analysis of sugarcane bagasse pith: a comparative evaluation with other sugarcane residues

In this study, thermogravimetric and thermo-kinetic analysis of sugarcane bagasse pith (S.B.P.) were performed using a robust suite of experiments and kinetic analyses, along with a comparative evaluation on the thermo-kinetic characteristics of two other major sugarcane residues, namely sugarcane straw (S.C.S.) and sugarcane bagasse (S.C.B.). The thermogravimetric analysis evaluated the pyrolysis behavior of these residues at different heating rates in a nitrogen atmosphere. The Kissinger, advanced non-linear isoconversional (ANIC), and Friedman methods were employed to obtain effective activation energies. Moreover, the compensation effect theory (CE) and combined kinetic analysis (CKA) were used to determine the pre-exponential factor and pyrolysis kinetic model. Friedman's method findings indicated that the average activation energies of S.C.S., S.C.B., and S.B.P. are 188, 170, and 151 kJ/mol, respectively. The results of the ANIC method under the integral step Δα = 0.01 were closely aligned with those of the Friedman method. The CKA and CE techniques estimated ln(f(α)Aα) with an average relative error below 0.7%. The pre-exponential factors of S.C.S., S.C.B., and S.B.P. were in the order of 1014, 1012, and 1011 (s-1), respectively. From a thermodynamic viewpoint, positive ∆G* and ∆H* results provide evidence for the non-spontaneous and endothermic nature of the pyrolysis process, indicating the occurrence of endergonic reactions.

Advanced biofuel production, policy and technological implementation of nano-additives for sustainable environmental management - A critical review

This review article critically evaluates the significance of adopting advanced biofuel production techniques that employ lignocellulosic materials, waste biomass, and cutting-edge technology, to achieve sustainable environmental stewardship. Through the analysis of conducted research and development initiatives, the study highlights the potential of these techniques in addressing the challenges of feedstock supply and environmental impact and implementation policies that have historically plagued the conventional biofuel industry. The integration of state-of-the-art technologies, such as nanotechnology, pre-treatments and enzymatic processes, has shown considerable promise in enhancing the productivity, quality, and environmental performance of biofuel production. These developments have improved conversion methods, feedstock efficiency, and reduced environmental impacts. They aid in creating a greener and sustainable future by encouraging the adoption of sustainable feedstocks, mitigating greenhouse gas emissions, and accelerating the shift to cleaner energy sources. To realize the full potential of these techniques, continued collaboration between academia, industry representatives, and policymakers remains essential.

Determination of thermal degradation behavior and kinetics parameters of chemically modified sun hemp biomass

Sun hemp fibers are natural fibers obtained from plants grown in India and nearby countries. It is lignocellulosic biomass having the complex structure of hemicelluloses, cellulose and lignin. Chemical treatment of natural fibers is in practice to enhance the properties being used as reinforcement. Alkaline-treated fiber was sampled and thermal stability along with kinetic parameters was assessed with thermo gravimetric data at heating rates 10, 20 and 30 °C/min using four model-free methods Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), Friedman (FM), Starink (STAR) along with Distributed activation energy model (DAEM) to calculate pre-exponential factor. The calculated activation energy E_a by these model-free methods were in the range of 93.3-104.8 kJ/mol and pre-exponential factor (A) was observed between the range 46.6 x10³-90.5 x10⁶/min by the DAEM method. The standard deviation (σ) calculated from average activation energy using all four methods was 4.5 kJ/mol, which showed the consistency in the methods employed to determine the activation energy of sun hemp.

Biochar and bio-oil fuel properties from nickel nanoparticles assisted pyrolysis of cassava peel

Direct biomass usage as a renewable fuel source and substitute for fossil fuels is discouraging due to high moisture, low energy density and low bulk density. Herein, thermogravimetric analysis (TGA) was conducted at various heating rates to determine peak decomposition temperatures for the dried cassava peels (DCP). The influence of pyrolysis temperature (300, 400, 500 and 600 °C) and heating rates (10, 20 and 30 °C/min) on the nickel nanoparticles catalyzed decomposition of DCP to produce biochar, bio-oil and biogas was investigated and characterized. The results revealed higher biochar (CBC) yield of 68.59 wt%, 62.55 wt% and 56.92 wt% at lower pyrolysis temperature of 300 °C for the different heating rates of 10, 20 and 30 °C/min. The higher carbon content of 52.39, 53.30 and 55.44 wt% was obtained at elevated temperature of 600 °C and heating rates of 10, 20 and 30 °C/min, respectively. At the pyrolysis temperature of 600 °C and heating rates of 10, 20 and 30 °C/min, the optimum yield of bio-oil (24.35, 17.69 and 18.16 wt%) and biogas (31.35, 42.03 and 46.12 wt%) were attained. A high heating value (HHV) of 28.70 MJ/kg was obtained for the biochar at 600 °C. Through the TGA, FTIR and HRSEM results, the thermal stability, hydrophobicity and structural changes of DCP and CBC samples were established. Similarly, the thermal stability of CBC samples increased with increasing pyrolysis temperature. Biochar with optimum fuel properties was produced at 600 °C due to the highest carbon content and high heating value (HHV). Improved kinematic viscosity (3.87 mm²/s) and density (0.850 g/cm³) were reported at the temperature of 300 °C and heating rate of 30 °C/min, while a higher pH (4.96), HHV (42.68 MJ/kg) and flash point (53.85 min) were presented by the bio-oil at the temperature of 600 °C and heating rate of 30 °C/min. Hence, DCP produced value-added biochar and bio-oil as renewable energy.

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Nickel nanoparticles successfully catalyzed the pyrolysis of CP biomass.

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Temperature and heating rates affected the yield of pyrolysis products.

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Fixed carbon content increased rapidly with temperature increase.

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The HHV of both biochar and bio-oil was higher than the DCP biomass.

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The fuel properties of biochar and bio-oil improved rapidly through NiNPs catalyzed pyrolysis.

Insights into kinetic and thermodynamic analyses of co-pyrolysis of wheat straw and plastic waste via thermogravimetric analysis

This work studied the co-pyrolysis of wheat straw (WS) and polyethylene (PE) via thermogravimetric experiments from room temperature to 1000 °C at various heating rates (10, 20, and 30 °C/min). Thermal behavior revealed that the maximum decomposition of WS, PE, and their blend occurred in three temperature ranges, viz. 250 - 496, 200 - 486, and 200 - 501 °C. Kinetic parameters were determined using model-free isoconversional methods. Activation energy from KAS (163.56, 220.26 and 196.78 kJ/mol for WS, PE, and blend), FWO (165.97, 222.05, 198.86 kJ/mol for WS, PE, and blend), and Starink (163.45, 220.05, 196.46 kJ/mol for WS, PE, and blend) method was estimated. From among various solid-state kinetic models, first-order reaction kinetics and one and two-dimensional diffusion models dominated co-pyrolysis of WS and PE. Thermodynamic parameters confirmed the feasibility of co-pyrolysis of WS and PE while differential thermal analysis signified that endothermic and exothermic reactions occur simultaneously.

Catalytic pyrolysis of lignocellulosic biomass for bio-oil production: A review

Catalytic pyrolysis has been widely explored for bio-oil production from lignocellulosic biomass owing to its high feasibility and large-scale production potential. The aim of this review was to summarize recent findings on bio-oil production through catalytic pyrolysis using lignocellulosic biomass as feedstock. Lignocellulosic biomass, structural components and fundamentals of biomass catalytic pyrolysis were explored and summarized. The current status of bio-oil yield and quality from catalytic fast pyrolysis was reviewed and presented in the current review. The potential effects of pyrolysis process parameters, including catalysts, pyrolysis conditions, reactor types and reaction modes on bio-oil production are also presented. Techno-economic analysis of full-scale commercialization of bio-oil production through the catalytic pyrolysis pathway was reviewed. Further, limitations associated with current practices and future prospects of catalytic pyrolysis for production of high-quality bio-oils were summarized. This review summarizes the process of bio-oil production from catalytic pyrolysis and provides a general scientific reference for further studies.

Pyrolysis of pigeon pea (Cajanus cajan) stalk: Kinetics and thermodynamic analysis of degradation stages via isoconversional and master plot methods

Detailed analysis of thermo-kinetics, reaction mechanism, and estimation of thermodynamic parameters are imperative for the design of reactor systems in thermochemical conversion processes. Present investigation was aimed at exploring the pyrolysis potential of pigeon pea stalk (PPS) by thermogravimetric experiments at 10, 20, and 30 °C/min heating rates. Maximum devolatilization of PPS was found to take place below 480 °C. The average activation energy for PPS pyrolysis was found to be 95.97, 100.74, 96.24, and 96.64 kJ/mol by Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, Starink, and Friedman method, respectively. Statistical analysis by one way analysis of variance method by employing Tukey test revealed that the difference in activation energy estimated from different methods was insignificant. Thermodynamic parameters (ΔH, ΔS_, and ΔG) together with reaction mechanisms were also evaluated. Difference in the activation energy and enthalpy was found to be less than 5 kJ/mol. R2 and R3 models were found best fitted with experimental PPS pyrolysis data.

Thermogravimetric pyrolysis of onion skins: Determination of kinetic and thermodynamic parameters for devolatilization stages using the combinations of isoconversional and master plot methods

Thermogravimetric pyrolysis of onions skins was studied thoroughly for the first time. Kinetic calculations of devolatilization stages were performed applying direct Arrhenius plot (DAP) method and combinations of isoconversional and Criado's Z(α) master plot (CZMP) methods. The kinetic parameters calculated using combined methods were utilized successfully to reproduce the experimental kinetic curves whereas those calculated using DAP method failed in this sense. The average E_a values of isoconversional methods were between 164.0 and 172.0 kJ/mol. The CZMP method yielded multiple F-type reaction mechanisms. The simplified kinetic models of combined methods were also developed by using single reaction mechanisms deduced from multiple reaction mechanisms. The Friedman-CZMP combination was the best option for developing simplified/unsimplified kinetic models. Determination of reaction mechanism using DAP method by searching for the highest R² value of regression equation among several candidates was found unreliable. ΔH, ΔG and ΔS values were calculated for 10 °C/min heating rate.

The effect of Ca/Mg/Zn mixing ratio on the research octane number of bio-gasoline during basic soap pyrolysis

Pyrolysis is one of the available technologies to convert oleic basic soap into gasoline-compatible fuel. In this research, the process mentioned was applied using the mixture of Ca, Mg, Zn in the production of oleic basic soap. The reactions were carried out in a batch glass reactor at atmospheric pressure at the temperature of 450 °C. Meanwhile, the basic soaps were made by reacting oleic acid mixed with metal hydroxides. The parameters observed were the Research Octane Number (RON) of bio-gasoline and the hydrocarbon content in the liquid product. The higher the octane number is, the better gasoline resists detonation and the smoother the engine runs. As observed, pyrolysis of oleic basic soap produced gasoline range hydrocarbon. GC-DHA results indicated that the highest RON (89.6) was achieved with Ca/Mg/Zn ratio of 0.15:0.85:1 (Ca-metal ratio of 0.15 mol). The products of the pyrolysis process comprised bio-hydrocarbon, solid residue, water, and gas. The bio-hydrocarbon contents were paraffin (5.9 wt%), iso-paraffin (31.3 wt%), olefin (18.5 wt%), naphthene (25.3 wt%), and aromatic compounds (15.3 wt%).