The pyrolysis process is one of the most widely practised thermochemical pathways for converting biomass into biofuel. The most challenging aspect of the pyrolysis conversion is modelling the thermal ...decomposition kinetics of lignocellulosic biomass. Therefore, this study aimed to develop a generic hybrid intelligent model to describe biomass pyrolysis kinetics based on the ultimate analysis (carbon, hydrogen, oxygen, nitrogen, sulfur content) and process heating rate. First, an analytical model was fitted to the experimental data from thermogravimetric analysis reported in the published literature to determine the pyrolysis kinetic parameters of a wide range of biomass feedstocks. The derived kinetic parameters of biomass pyrolysis (i.e., reaction order, frequency factor, activation energy) were then modelled using three exclusive Adaptive Neuro-Fuzzy Inference System (ANFIS) models tuned by genetic algorithm (GA). The capability of the GA-ANFIS approach in modelling the kinetic parameters of biomass was also compared with that of the classical ANFIS model. The obtained results showed that the GA-ANFIS approach outperformed the classical ANFIS model in estimating the pyrolysis kinetic parameters of biomass. Generally, the highly nonlinear and extremely complex kinetic parameters of biomass thermal degradation were satisfactorily estimated using the GA-ANFIS models with a coefficient of determination exceeding 0.940 and a mean absolute error lower than 0.096. The pyrolysis reaction kinetics of five biomass materials, unexploited during the development of the GA-ANFIS models, were estimated with a correlation coefficient higher than 0.811 and a mean absolute error lower than 0.7376 using the generic hybrid intelligent model. The promising agreement between the predicted and experimental kinetic data suggested that the generic hybrid intelligent model could be an alternative to the laborious experimental thermogravimetric measurements, thereby allowing pyrolysis process optimization, monitoring, and controlling to be more effectively conducted. Finally, an easy-to-use software package was developed based on the developed generic hybrid intelligent model to describe the devolatilization behaviour of biomass.
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•A generic hybrid intelligent model is developed to describe biomass pyrolysis kinetics.•The model input parameters were the ultimate analysis and process heating rate.•The genetic algorithm substantially improved the accuracy of the neuro-fuzzy approach.•The developed model adequately estimated the pyrolysis kinetic parameters of biomass.•The model can predict the pyrolysis kinetics of unexploited biomass with an R2 > 0.811.
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•VAn-P breaks the record of plasticity of flame-retardant plasticizers.•The VAn-P addresses the issue with traditional flame-retardant solutions.•Vanillate plasticizer VAn-P has a ...multi-functional gain on PVC.•Effects of chain length on vanillate plasticizer is novelly studied.
The current market for poly(vinyl chloride) (PVC) plasticizers is dominated by flammable petroleum-based compounds, accounting for over 80 % of the total share. Due to their high flammability, the search for novel approaches to enhance the fire resistance of flexible PVC has gained urgency. However, traditional flame-retardant schemes suffer from shortcomings such as poor compatibility, inferior long-term performance, and weak mechanical properties. Herein, we synthesized a novel biobased flame-retardant plasticizer (VAn-P) using vanillic acid as a skeleton. This plasticizer exhibits remarkable properties, including a substantially lower glass transition temperature compared to unplasticized PVC. The binding energy between VAn-P and PVC is calculated to be –33.30 kcal/mole, indicating a strong interaction. Furthermore, the maximum elongation at break of VAn-P plasticized PVC is 16 times higher than that of unmodified PVC. All PVC samples plasticized with VAn-P achieved a UL-94 VTM-0 rating. TGA-FTIR analysis revealed that the flame-retarding mechanism of VAn-P involves solid-phase action, significantly delaying the dehydrochlorination process of PVC. Moreover, VAn-P exhibits superior migration resistance compared to dioctyl phthalate (DOP). We also investigated the effects of alkyl chain lengths in VAn-P on various properties of PVC blends, including thermal stability, flame retardancy, mechanical properties, and optical performance. The toxicity of vanillic acid-based flame-retardant plasticizer has undergone an initial assessment. Overall, this green plasticizer is expected to endow polymers with high plasticizing performance and flame retardancy, providing a novel and sustainable approach for the synthesis of functional plasticizers.
•AAEMs in biomass removed by acid washing or passivated by acid infusion.•Sugar-rich streams produced from pyrolysis of acid pretreated corn stover.•Interactions between cellulose and lignin ...component for acid infused corn stover.•Temperature-evolution of major phenolic monomers from lignin depicted.
Naturally occurring AAEMs in biomass exhibit detrimental effects to biomass pyrolysis as producing less oil with lower quality. Acid pretreatments are cheap and effective methods for mitigating AAEMs effect, thus improving the pyrolysis performance. In the current study, a combination of different experiment techniques and theoretical kinetic analysis was conducted to systematically compare the effects of both acid infusion and washing pretreatments. By utilizing Py-GC/MS system, the product distribution from pyrolysis of raw and acid pretreated corn stovers was obtained. Compared to that of raw corn stover, significant reduction of char and improvement of sugars, especially levoglucosan (55% yield based on cellulose), from pyrolysis of acid washed corn stover were achieved because of the thorough removal of AAEMs in corn stover. As for acid infused corn stover, maintaining reaction in acid buffer condition (3~5 wt% acid infusion) kept the sugar yield at relatively high level. Further increase of acid infusion over 5 wt% resulted in strong dehydration reaction of sugars and sharp decrease of phenolic compounds. The DTG pattern and the key kinetic parameters of corn stover dramatically changed with acid pretreatment. Strong condensation reaction between cellulose and lignin in acid infused corn stover were also suggested by kinetic analysis. Besides, the evolution of major phenolic monomers from lignin component versus temperature was revealed by TG/PI-TOF-MS system. As for acid pretreated corn stover, the agglomeration associated with the increase of char production were further ascribed to the enhanced polymerization of vinyl-phenols and other simple phenols. Overall, the study provides insights into the fast pyrolysis behavior of acid pretreated biomass for producing high-quality bio-oil and value-added chemicals.
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•Using PTASA to promote PTL pyrolysis for high-quality syngas was firstly proposed.•The kinetic mechanism of PTASA in the pyrolysis of PTL was revealed.•PTASA mainly decreased the ...activation energy of Lignin in PTL by19%.•High-quality syngas increased evidently from 0.415 to 0.523 L/g with PTASA.•Inherent minerals in PTASA could break macromolecule bonds to promote PTL pyrolysis.
To improve pyrolysis syngas of Phoenix Tree’s Leaves (PTL), the synergistic effect of Purified Terephthalic Acid Sludge Ash (PTASA) was comprehensively investigated. In kinetics analysis, the thermal decomposition of PTL could be divided into three pseudoreactions while PTL + PTASA was with four pseudoreactions owing to the decomposition of CaCO3 as well as the reduction of inherent metal compounds (Co(II), Mn(III, IV), etc). Meanwhile, the reaction models for pseudoreaction 1 (P1) ∼ pseudoreaction 4 (P4) were fitted as D3, R2 and D3, and A15, respectively. The Ea (average activation energy) of PTL + PTASA during pyrolysis (200 ∼ 600 °C) was 6.2 % lower than the monopyrolysis which was mainly caused by the decrease of Ea in the decomposition of lignin. In addition, the crystal structure e.g. CaMnO3 (ABO3), Ca3Co2O6 (A3BB’O6), and CoO in PTASA could effectively promote the production of high-quality syngas from 41.34 % to 61.76 %. Moreover, the reaction pathways in pyrolysis of PTL + PTASA showed that the PTASA could promote the CC bond, CO bond, and C–H bond breaking of the macromolecules, e.g. anhydrosugars, N-containing compounds, and aldehydes, to produce the small molecules and release syngas. This study could provide a useful strategy for clean, valuable, and sustainable resource utilization of waste resources.
Thermogravimetric pyrolysis of carnauba straw and carnauba stalk was studied for the first time. The experiments were carried out at four different heating rates (5–20 °C min−1) and the kinetic ...parameters were calculated using three isoconversional methods such as Friedman (differential), KAS (integral), and OFW (integral). The activation energies and R2 were calculated for the conversions between 0.10 and 0.90. The average activation energies were found to be 225.28 (±26.83 kJ mol−1) for carnauba straw and 218.13 (±28.06 kJ mol−1) for carnauba stalk by the Friedman method; 223.17 (±17.72 kJ mol−1) for carnauba straw and 211.04 (±18.82 kJ mol−1) for carnauba stalk by KAS method; and 212.71 (±23.19 kJ mol−1) for carnauba straw and 217.94 (±17.85 kJ mol−1) for carnauba stalk by OFW method. The FTIR spectra showed bands characteristic of hemicellulose, cellulose, and lignin at 3331 cm−1 (O–H) and 3345 cm−1 (O–H); 2919 cm−1 (C–H) and 2928 cm−1 (C–H); and 1733 cm−1 (CO) and1723 cm−1 (CO). The carnauba straw presented molar ratios of 1.43 (H/C) and 0.78 (O/C), and the carnauba stalk of 1.39 (H/C) and 0.81 (O/C). The kinetic parameters, FTIR spectra, and molar ratios are in good agreement with other reported biomasses.
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This study comprehensively investigates the potential of reed straw waste (RSW) for thermochemical conversion into bioenergy and value-added chemicals. The physicochemical property characterization ...confirmed the potential of RSW as both a renewable fuel and a source of chemical compounds. The high heating value (17.16 ± 0.20 MJ/kg), average activation energy (253.10–297.04 kJ mol−1), Gibbs free energy (153.45–158.39 kJ mol−1), and enthalpy change (248.10–292.04 kJ mol−1), underscored the significant potential of RSW for bioenergy production through pyrolysis and its compatibility for co-pyrolysis with other waste materials. Pyrolysis product analysis revealed that syngas constituted 42.25–66.48 % of the total three-phase products, with combustible components like H2, CO, and CH4 comprising 84.14–89.77 % of syngas. Bio-oil represented 18.94–35.23 % of the total three-phase products, primarily composed of phenols (30.88–46.04 %), acids (1.12–16.05 %), furans (8.84–14.46 %), ketones (9.34–16.33 %), alcohols (4.59–13.68 %), and aldehydes (5.54–11.10 %). BET and FTIR analysis of the biochar indicated that RSW biochar possessed a well-defined porous structure and abundant surface functional groups, making it capable of achieving a maximum adsorption capacity of 185.35 mg g−1 for the malachite green (MG) dye in the aquatic environment. In summary, this study holds significant implications for mitigating environmental pollution resulting from improper disposal of RSW and promoting its high-value utilization.
The presence of persistent free radicals (PFR) in biochars may greatly broaden the application of biochars in pollution control, but may also cause negative impacts to the environment. Understanding ...the structural basis and the formation mechanisms of PFR is essential for a targeted biochar production and application. This study used rice straw (RS), a ubiquitous agricultural waste, to investigate the generation processes of PFR in relation to RS pyrolysis kinetics. Based on a detailed thermogravimetric (TG) and derivative thermogravimetric (DTG) analysis, the activation energy was calculated by Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods. This work combined pyrolysis kinetics analysis and solid particle characterization. Our results showed that lignin started to pyrolyze at a lower temperature than cellulose and hemicellulose. Lignin was the main factor for PFR generation. Chemical bond breaking contributed only slightly to PFR formation. The reconfiguration of the carbonaceous structures may be a more important contributor to PFR formation, while the cross-linking between different compositions and the interactions between the chemical compositions and inorganic minerals may play a significant role for PFR generation and stabilization in RS. This study provides useful theoretical basis to understand the thermal pyrolysis process of RS and the manipulation of biochar properties.
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•Similar activation energies are obtained by KAS and FWO methods.•Lignin pyrolyzes at a lower temperature than cellulose and hemicellulose•Lignin is a main contributor to PFR generation in rice straw biochar.•Carbonization of the structures is the major process for PFR generation.
This study presents a comprehensive investigation into the physicochemical properties of banana peel waste (BPW) and its potential for thermochemical conversion into bioenergy and value-added ...chemicals, supported by the results of kinetics, thermodynamics, in-situ volatile products, and biochar analysis. The physicochemical analysis confirms its potential as a source of renewable fuels and valuable chemicals. Subsequently, based on the TGA outcomes, both kinetic and thermodynamic analysis were conducted. The average activation energy (226–257 kJ mol−1), high heating value (19.56 MJ kg−1), Gibbs free energy (118–149 kJ mol−1), and enthalpy change (222–252 kJ mol−1) all underscore the substantial potential of BPW for bioenergy production and its compatibility for co-pyrolysis with other waste materials. Moreover, Py-GC/MS analysis reveals that the pyrolysis of BPW primarily yields volatile products such as acids, aldehydes, alcohols and ketones, offering a potential source of value-added chemicals. Furthermore, the residual solid biochar exhibits an impressive maximum adsorption capacity of 360.18 mg g−1 for Cd(II) in aqueous environments, thereby further highlighting the exceptional quality of BPW-derived biochar as a superior adsorbent for heavy metals. In summary, this study holds significant importance in promoting the efficient utilization of BPW and mitigating the environmental pollution resulting from improper disposal.
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•Kinetic and thermodynamic parameters were calculated to understand BPW pyrolysis behavior.•Acids, aldehydes, alcohols and ketones are the predominant volatile products.•Biochar exhibits excellent adsorption performance towards Cd(II).•BPW emerges as an appealing feedstock for the bioenergy and value-added chemicals production.
The co-pyrolysis of bamboo sawdust (BSD) and linear low-density polyethylene (LLDPE) is studied for the first time using thermogravimetric analysis (TGA) in the temperature range of 30–900 °C at ...heating rates 5, 10 and 20 °C·min−1. A blend containing 25 wt% BSD and 75 wt% LLDPE (BP1:3) shows the highest synergism as compared to other blends studied. The activation energy drop (36% with respect to biomass) is also highest with this blend. The kinetic parameters are determined using three models based on the isoconversional method: Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW), and Friedman (FM) models. The mean values of apparent activation energy for the decomposition of blends (BP3:1 (75 wt% BSD and 25 wt% LLDPE), BP1:1 (50 wt% BSD and 50 wt% LLDPE) and BP1:3) are determined to be 357, 371 and 143 kJ mol−1 from KAS, 368, 400 and 165 kJ mol−1 from OFW and 468, 356 and 255 kJ mol−1 from FM, respectively. The reaction follows a multistep mechanism as depicted by Criado’s master plot. The decomposition of the blend BP1:3 follows a nucleation growth (A2) model in the lower conversion range and diffusion (D2) model in the higher conversion range.
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•The co-pyrolysis of bamboo biomass and LLDPE is studied using thermogravimetry.•The highest synergism and an Ea drop of 36% with the blend 1:3 biomass:plastic.•Master plot: A2, and D2 mechanisms at lower and higher conversions, respectively.•The Ea for the blends 3:1, 1:1 and 1:3 are 397, 376, and 188 kJ mol−1, respectively.•The mean reactivity order of blends is found to be 1:3 > 1:1 > 3:1 at all heating rates.
•Pyrolysis and Copyrolysis of various medical waste were characterized.•Blending of various MW components reduced the activation energy of process.•SY5MG5, SY7CS3, and MG7CS3 pyrolysis followed R3, ...D2, and D1 reaction models.•Copyrolysis of SY, MG, and CS brought significant changes to the products distribution of MW.
The COVID-19 pandemic has caused a substantial rise in the amount of medical waste, posing additional hurdles in waste management. Disposing of this waste properly is essential to curb transmission of the diseases. The pyrolysis reaction kinetics, synergistic interactions, and pyrolysis gas release behavior of typical constituents of medical waste (MW): syringe (SY), medical gloves (MG), cotton swab sticks (CS), and their blends were examined by utilizing advanced analytical techniques including TG, TG-FTIR, TG-MS, and kinetic models (Friedman, KAS). The experiments were conducted using a wide range of heating rates, namely 10, 20, 30, and 40 °C⋅min−1. The pyrolysis reactions were mainly endothermic, with main stages ranging from 352.0–480.0 °C, from 381.0–511.0 °C, from 200.0–404.5 °C, 336.6–509.9 °C, 375.4–477.6 °C, 384.0–500.9 °C, for SY, MG, CS, SY5MG5, SY7CS3, and MG7CS3, respectively. According to the KAS method, the average activation energies for the mono-pyrolysis of SY, MG, and CS were determined as 240.8, 226.1, and 147.5 kJ⋅mol−1 respectively. Interestingly, during the pyrolysis of blends such as SY5MG5, SY7CS3, and MG7CS3, the activation energies decreased to 177.2, 159.9, and 149.1 kJ⋅mol−1 respectively. Notably, the experimental activation energy values (Eexp) obtained during the co-pyrolysis were significantly lower than the calculated values (Ecal), revealing an apparent synergistic effect during the pyrolysis of various MW blends. The pyrolysis process of MW blends resulted in the release of significant volatile components, including CH4, CO, C3H6, CO2, C2H5OH, C4H8, C5H8, C6H6, C6H14, C7H8, and C8H10. The specific composition of these volatile components varied depending on the types of waste present in the blends.
