A generalized activation energy equation for torrefaction of hardwood biomasses based on isoconversional methods

Grigiante, M.; Brighenti, M.; Antolini, D.

doi:10.1016/j.renene.2016.07.054

Cited by 16 publications

(6 citation statements)

References 59 publications

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“…Therefore, from this comparison, it can be inferred that agricultural biomass, such as: raw OPFP, showed higher Eα values of 239.03 kJ/mol (Table 3), as compared to woody biomass, which is agreeable to the current results obtained. An increase of Eα values during Stage 1 was also expected where according to Grigiante et al [31], this is due to the random scission of linear chain in hemicellulose which led to the rise in Eα values as the thermal heating progressed. The crosslinking behavior and its effects on the numerously branched polymeric structure of hemicellulose and extractives constituents that yet to be degraded, gave rise to the Eα values upon thermal heating.…”

Section: Model-free Kinetic Evaluation Via Kas Methodssupporting

confidence: 63%

“…Average Eα values are noticeably high in ROPFP (239-251 kJ/mol) in which, based on the literatures on various agricultural residues kinetic studies, Ea calculated for various types of biomass are as follows; rice straw (140-267 kJ/mol) [26], rice husk (168 kJ/mol) [28], olive pomace (162-602 kJ/mol) [29], bagasse (169 kJ/mol) [28], and olive tree pruning (151-209 kJ/mol) [30]. Whereas, from previous studies on woody biomass of different categories (softwood/hardwood) showed lower Eα values via various non-isothermal kinetic methods, for example; ashwood-hardwood (133-167 kJ/mol) [31], poplar wood (159 kJ/mol) [32], Ahun wood (127 kJ/mol) and Araba wood (125 kJ/mol) [33]. Therefore, from this comparison, it can be inferred that agricultural biomass, such as: raw OPFP, showed higher Eα values of 239.03 kJ/mol (Table 3), as compared to woody biomass, which is agreeable to the current results obtained.…”

Section: Model-free Kinetic Evaluation Via Kas Methodsmentioning

confidence: 94%

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Dynamic Model-Free and Model-Fitting Kinetic Analysis during Torrefaction of Oil Palm Frond Pellets

Matali

Rahman

Idris

et al. 2020

Bull. Chem. React. Eng. Catal.

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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

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Section: Model-free Kinetic Evaluation Via Kas Methodssupporting

confidence: 63%

Section: Model-free Kinetic Evaluation Via Kas Methodsmentioning

confidence: 94%

Dynamic Model-Free and Model-Fitting Kinetic Analysis during Torrefaction of Oil Palm Frond Pellets

Matali

Rahman

Idris

et al. 2020

Bull. Chem. React. Eng. Catal.

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“…Thus, the positive correlation between the contents of H and the HHV presented in the Section 3.3 (r = 0.43), which is according to Ref. [42][43][44]. However, there are authors who argue that the component that most influences HHV values is C, e.g., [19,24,25,30].…”

Section: Elemental Analysis (Chons) and Ashesmentioning

confidence: 71%

Residual Agroforestry Biomass–Thermochemical Properties

Enes

Aranha

Fonseca

et al. 2019

Forests

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Research Highlights: Biomass from Mediterranean agroforestry vegetation may be a potential source of renewable energy. However, due to the high heterogeneity of this type of resource, the study of its characteristics becomes necessary for its efficient use. Objectives: The aim of this study was to evaluate the thermal and chemical properties of 14 different kinds of agroforestry biomass groups: shrubs, forest, and agricultural wastes. Materials and Methods: The higher heating value (HHV), the elemental analysis (C, H, O, N, S), ashes, mineral elements (Na, K, Ca, Mg, and P), trace elements (Mn, Fe, Zn, Ni, Cu, Cr, and Cd) and halogen elements (F and Cl) were quantified and compared with CEN/TS 147775 and CENS/TS 14961 standards, looking forward to future use for energy purposes, namely through combustion processes, as an alternative to fossil fuels. Results: The shrubs present the highest values of higher heating value (20.5 MJ kg−1), followed by the forest wastes (19.2 MJ kg−1) and the lowest in the agricultural wastes (18.5 MJ kg−1). Concerning the elemental analysis, the difference between groups C, H, and O are very small and not statistically significant, while for N, S and ashes values are higher in agricultural than shrubs and forestry wastes. The same tendency was found for the mineral nutrients. For the trace elements, the lowest content of Mn, Fe, and Zn is found in agricultural, Ni, and Cr content in the shrubs and Cu in the forest wastes. The halogen elements are present in greater amount in shrubs than agricultural and forest wastes. Conclusions: Although the high values of the halogen elements which may raise sintering problems and corrosive effect on metal parts in furnace and boiler, in general the shrubs biomass are those with better characteristics for energy uses, namely through combustion processes.

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“…A slight variability in the calorific value can be witnessed and occurs due to certain variability in the elementary H content. It also occurs as a result of a much larger variability in ash contents [19].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Physical, Chemical and Thermal Properties of Portuguese Maritime Pine Biomass

et al. 2018

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A characterisation of Pinus pinaster Aiton. (Maritime Pine) woody biomass and ashes is presented in this study. Physical, thermal and chemical analysis, including density, moisture content, calorific value, proximate and ultimate analysis, were carried out. The fuel Energy Density (Ed) and the Fuelwood Value Index (FVI) were assessed by ranking the fuelwood quality. Furthermore, the determination of the ash metal elementals was performed. The results from this study indicated, for Pinus pinaster biomass tree components, carbon content ranging from 46.5 to 49.3%, nitrogen content from 0.13 to 1.18%, sulphur content from 0.056 to 0.148% and hydrogen content around 6–7%. The ash content in the tree components ranged from 0.22 to 1.92%. The average higher heating value (HHV) was higher for pine needles (21.61 MJ·kg−1). The Ed of 8.9 GJ·m−3 confirm the good potential of Pinus pinaster biomass tree components as fuel. The FVI ranked the wood stem (4658) and top (2861.8) as a better fuelwood and pine needles (394.2) as inferior quality. The chemical composition of the ashes revealed that the elemental contents are below the national and most European countries legislation guidelines for the employment of ash as a fertiliser.

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A generalized activation energy equation for torrefaction of hardwood biomasses based on isoconversional methods

Cited by 16 publications

References 59 publications

Dynamic Model-Free and Model-Fitting Kinetic Analysis during Torrefaction of Oil Palm Frond Pellets

Dynamic Model-Free and Model-Fitting Kinetic Analysis during Torrefaction of Oil Palm Frond Pellets

Residual Agroforestry Biomass–Thermochemical Properties

Evaluation of the Physical, Chemical and Thermal Properties of Portuguese Maritime Pine Biomass

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