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Thermal characterization of mustard straw and stalk in nitrogen at different heating rates
Abstract
The pyrolysis of mustard straw and stalk was investigated at different heating rates from the ambient temperature to a temperature of 700 °C in a dynamic nitrogen flow of 40 cc/min. The thermogravimetric (TG) and derivative thermogravimetric analysis (DTG) profiles were examined for the entire degradation zone to determine the order of reaction, pre-exponential factor and activation energy. The orders of reaction were in the range of 0.61–1.02, activation energy in the range of 10.83–21.63 kJ/mol and pre-exponential factor was in the range of 15.67–27.2 min−1. This study of kinetics of pyrolysis of this abundant biomass is helpful in developing the mechanism of a thermochemical conversion process.
... The conversion rate (α), as de ned by Maiti et al. [35], is given by Eq. 3 ...
... T p ) occurred. It should be noted that the temperature range or conversion range used to perform the kinetic analysis may a ect the values of the kinetic parameters obtained [5,26,35,37]. Therefore, the Coats-Redfern kinetic analysis executed in the present work was performed in accordance with the work of Peng and Wu [37], as a reaction zone of T o -400 o C, was chosen as the temperature range used to describe the kinetics of thermal decomposition reaction for the biomass samples as a ected by extractives. ...
... The E a values presented in their work ranged from ~24-58 kJ.mol -1 . The work of Maiti et al. [35] characterized the thermal decomposition behaviour of mustard straw and provided E a values ranging from ~13-192 kJ.mol -1 , depending on heating rate and reaction zone used to calculate the activation energy. This work also noted that E a values increased when heating rate increased from 5 to 15 o C.min -1 but a further increase in heating rate to 50 °C.min ...
A kinetic study was performed using the Kissinger and Coats-Redfern methods to examine the effect of extractives on thermal decomposition of three crop residues, wheat straw, triticale straw and flax shives. The extractives-free crop residues required higher temperatures for the onset of thermal decomposition than the corresponding native/unextracted samples. Activation energy (Ea) values varied according to kinetic analysis and the extractives-free samples generally showed significantly higher Ea values (65-214 kJ.mol-1) than the native/unextracted samples (58-205 kJ.mol-1). This information is necessary for defining the use of crop residues as agro-fillers in composite materials and feedstock for bioenergy and biochemical via pyrolysis. Keywords: wheat straw, triticale straw, flax shives, extractives, thermal decomposition, kinetic analysis, Kissinger method, Coats-Redfern method, activation energy.
... This was possibly due to a short residence time, which did not provide enough time for two particles to interact. Therefore, the evolution of volatile vapors decreased at a higher heating rate (Maiti et al. 2007). Figure 1a describes thermal decomposition curves for OPT in argon atmosphere in which average volatilized mass was 73.37 ± 1.73%, accounting for a maximum of 75.57% and a minimum of 71.34%, at heating rates of 30 and 10 ℃/min, respectively, and corresponding to a 3.5% deviation from average. ...
... Based on the findings, it was also noted that volatile products also increased with a rise in heating rates. However, total residence time increased at lower heating rates, leading to secondary reactions such as re-polymerization and recondensation that eventually lead to char formation (Maiti et al. 2007). The carbonization step refers to the process of thermal decomposition that occurred in the 450-700 °C temperature range and was only related to remaining biomass thermal decomposition (lignin-based structure). ...
... The kinetic degradation response is quite complex for biomass that acquired resistance at lower heating rates and maybe decreased resistance at higher heating rates due to higher heat and mass transfer across materials favoring a more advanced conversion. It is worth noting that the hypothesis above is true for given biomass, size, and operating conditions (Maiti et al. 2007;). ...
Biomass as a raw material has profound implications for thermal conversion processes. It is important to study the relationship between kinetic modeling to depict significant importance in thermal processing by estimating volatile yield and reaction performance during biomass decomposition. This work aimed to determine the thermal decomposition reaction kinetics of non-woody (oil palm trunk (OPT)) and woody (rubberwood sawdust (RWS)) biomass. Devolatilization of biomass is determined by the thermogravimetric analysis (TGA) at three different heating rates (10, 20, and 30 °C/min) using nitrogen as inert gas. The kinetic analysis used isoconversion models of Friedman, Ozawa-Flynn-Wall (OFW), and Kissinger–Akahira–Sunose (KAS). The activation energy varied from 218.4 to 303.8 kJ/mol (Friedman), 235.9 to 299.1 kJ/mol (OFW), and 235.8 to 298.9 kJ/mol (KAS) for OPT; and 199.7 to 228.1 kJ/mol (Friedman), 210.6 to 225.6 kJ/mol (OFW), and 210.7 to 225.2 kJ/mol (KAS) for RWS. The kinetic analysis indicated that RWS and OPT had diverse reaction kinetics, which depend on the reaction rate and order of the reaction. Experimental and theoretical conversion data agreed reasonably well, indicating that these results can be used for future OPT and RWS process modeling. Consistency of results is validated using GC–MS equipped with a pyrolyzer.
Graphical Abstract
... In a mustard stem and straw, one metric tonne of mustard seed produces 1.85 tonnes of agro residue [17]. Because MS is unfit for animal use as fodder due to its high glucosinolate content, a proper waste management plan is required to effectively utilise it as a potential fuel after using an appropriate thermal processing technique, one of which is pyrolysis [18]. Optimizing pyrolysis process parameters like activation energy and pre-exponential factor to maximize the desired product yield is critical for designing large-scale pyrolysis reactors [19]. ...
... rice husk, garlic husk, and banana leaves, are given in Table 2. Biomasses with a moisture content of less than10% form an ideal feedstock for the gasification, combustion, and pyrolysis conversion process. Moisture content of MS (8.9%) obtained in our experimentations agreed with a previous study [18]. Furthermore, MS biomass samples exhibit higher volatile matter (70.8%), fixed carbon (12.9%), and low ash content than other biomass samples (7.36%). ...
... Thermodynamic analysis Thermodynamic parameters, namely, enthalpy change (DH), Gibbs free energy change (DG), and entropy change (DS) were evaluated using Eqs. (18), (19), and (20) respectively, and their values are listed in Table 9. The data in Table 9 shows that all parameter values vary with a due to the complex reaction and composition of the samples during pyrolysis of MS reactions [32]. ...
Present work based on thermogravimetric analysis (TGA) to decipher in detail the pyrolysis of mustard stalk (MS) for investigating its potential for bioenergy feedstock at three heating rates (5, 10, and 20 °C/min). The thermal degradation behaviors of MS were carried out at three heating rates (5, 10, and 20 °C/min). The kinetic and thermodynamic parameters were examined using model-free isoconversional Flynn- Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) model. The obtained activation energy for pyrolysis of MS using FWO and KAS to be 132.47 and 130.62 kJ/mol. Kissinger method was used to compute pre-exponential factor found to be in the range of 10⁵ to 10¹⁶ s⁻¹ at different heating rates. The average ΔH was 127.70, and 125.8 kJ/mol and ΔG is 127.74 and 127.87 kJ/mol from FWO and KAS respectively, all ΔH positive indicated endothermic nature. The Coats-Redfern approach was used to estimate the thermal degradation reaction mechanism, which revealed that the diffusion model was best suited to reflect the degradation process involving both exothermic and endothermic reactions. The analysis can help augment the experimental studies, and physicochemical characterization revealed its fuel characteristic since MS is sustainable and promising biomass for alternative processes in terms of waste management strategies.
... The quality of biomass is checked by its heating value explicitly. Higher value of heating signifies the presence of energy value in the material [16]. To serve a purpose of obeying thermophysical properties, the material has to undergo various processes. ...
... The shape of DTG curve showing the absorbance of heat making it endothermic process. These endothermic peaks show the absorbance of energy during vaporization of moisture content from the sample [16]. ...
Thermophysical properties are calculated to determine performance parameters comprising specific heat capacity, thermal conductivity, thermal diffusivity and they are directly related to the dynamics of the material at atomic level and for thermal treatment of mustard husk (MSH) and MSH char, they play a vital role. Temperature dependence of thermophysical properties of MSH and MSH char have been investigated within the temperature range between 30 and 110 °C. MSH char is synthesized by the microwave pyrolysis of MSH. Thermogravimetric analysis of MSH and MSH char confirmed that MSH is more thermally stable as compared to MSH char. Moreover, it gave information about the degradation behaviour of MSH and MSH char. Thermophysical properties are measured by thermal analyser, based on the transient hot wire technique which is suitable to measure the thermal conductivity at elevated temperatures. At room temperature, thermal conductivity and thermal diffusivity of MSH are 0.187 W m ⁻¹ K ⁻¹ and 0.132 mm ² s ⁻¹ , respectively. Specific heat capacity of MSH and MSH char are found to be almost same (1.349 kJ kg ⁻¹ K ⁻¹ for MSH and 1.310 kJ kg ⁻¹ K ⁻¹ for MSH char). Thermal conductivity and thermal diffusivity values are decreasing on increasing the temperature while specific heat capacity is increasing linearly on increasing the temperature. Low thermal conductivity and thermal diffusivity values of MSH imply that the conventional conductive heating is less effective and inefficient for the thermal treatment of MSH.
... In contrast, at higher heating rates, there is usually a temperature gradient between the inner and outer part of the particles. Therefore, it is likely that there are differences in the degradation profile between a sample subjected to a high heating rate and one subjected to a low heating rate, since the degradation kinetics do not allow the completion of reactions at higher heating rates [41]. ...
... High heating rates favour rapid matter devolatilization [42], which contributes to the release of gases. In contrast, low heating rates prolong the residence time, Fig. 3 Linear regression for the estimation of the kinetic parameters of wood pyrolysis which contributes to the medium release of volatile matter, so that secondary reactions can occur, contributing to the formation of charcoal [41]. Thus, at low heating rates, it was possible to specifically detect the degradation of hemicelluloses, while at higher heating rates, there was overlap of the thermal decomposition of the cell wall structural carbohydrates, intensely and with greater reactivity, resulting in greater devolatilization. ...
Wood energy plantations are important sources of feedstock for bioeconomy, given their potential to replace fossil fuels, which would ultimately result in the reduction of greenhouse gas emissions. Eucalyptus and Corymbia woods have been widely used for the production of firewood, wood chips, and charcoal for the steel industry in Brazil. The present study aims to assess the properties of non-commercial Eucalyptus and Corymbia woods for energy purpose in Brazil. Six years after planting, the chemical, physical, energy, and thermal properties of Corymbia citriodora, Corymbia variegata, Corymbia henryi, Corymbia torelliana, Eucalyptus amplifolia, Eucalyptus longirostrata, Eucalyptus major, and Eucalyptus urophylla were analysed. The results showed significant variations in basic density (480-662 kg·m −3), total extractives (1.03-4.56% db), lignin (28.33-34.25% db), holocellulose (61.54-69.07% db), higher heating value (19.22-20.33 MJ·kg −1), syringyl/ guaiacyl ratio (2.20-3.36), energy density (9.45-12.51 GJ·m −3), ash content (< 1% db), and pyrolysis activation energy (247-468 kJ·mol −1). Compared to E. urophylla's wood, the most used species in the steel industry in Brazil, the wood from E. major, E. amplifolia, and C. torelliana had properties that favoured the production of high-quality charcoal for use in steel industry. C. citriodora, C. variegata, C. henryi, and E. longirostrata presented a high potential for use in energy cogenera-tion systems.
... The solid material (also called meal) left after the oil extraction from the seed is used as animal feed. The stalk and pod husk account for about 70 percent of the total mustard plant (Maiti et al., 2007). These are generally burn by the people for their household cooking purposes. ...
... Some effort has been made to generate basic scientific information on the fuel potential of rapeseed stalk and pod husk. Maiti et al., (2007) investigated physicochemical characteristics and kinetics of pyrolysis of mustard straw and husk using multiple linear regression analysis. Gao et al., 2017 studied the effect of temperature on the characteristics of pyrolytic product and the economics of rapeseed stalk as an energy source. ...
The aim of this work was to evaluate the pyrolysis of mustard straw (MS) in a thermogravimetric analyser and in a tubular reactor to recognize its bioenergy capability. The model free methods of Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS) and Vyazovkin were employed for kinetic analysis and Coats-Redfern (CR) method for elucidating the reaction mechanism. Response surface methodology (RSM) with central composite design technique was employed to optimize the pyrolysis process parameters to gain maximum amount of bio-oil. The highest bio-oil yield (44.69%) was obtained at the heating rate of 25 °C/min and at 500 °C under inert condition (N2 gas flow rate = 100 ml/min). Further, FTIR and GCMS analysis of bio-oil revealed the presence of different functional groups and valuable chemicals, whereas physicochemical characterization revealed its fuel characteristic. The results confirmed the suitability of mustard straw as a feed-stock for obtaining a cleaner fuel and value added products.
... Agricultural residues (stalks, husk, shells, etc.) mainly consist of cellulose, hemicellulose, and lignin in different proportions depending on the feedstock. They typically have a heating value in the range of 15-20 MJ/kg, which indicates the potential for their valorization [8][9][10][11]. Pyrolysis is a promising thermochemical conversion technology for the extraction of bio-energy and valuable chemicals in the form of bio-crude, gas, and biochar that have a wide range of applications [12,13]. ...
... The kinetics of beach and pine wood pyrolysis was investigated assuming parallel reaction scheme, where it was reported that the nth-order reaction model is followed in degradation of both substrates [17]. Kinetics of mustard stalk and straw were studied using standard Arrhenius rate equation with the nth-order reaction model for estimation of kinetic triplicates-order of reaction, pre-exponential factor, and activation energy [10]. They reported that the order of reactions was in the range of 0.61-1.02, ...
The purpose of this work was to establish the pyrolysis kinetics of agricultural biomass residues (mustard husk (MH), cotton stalk (CS), and groundnut shell (GNS)) using thermogravimetric analysis (TGA). TGA is carried out at different heating rates (5, 10, 30, and 50 K/min) under inert conditions in the temperature range of 303–1173 K. The iso-conversional methods of Friedman, Kissinger-Akahira-Sunose, and Flynn-Wall-Ozawa were used to estimate the activation energy of the decomposition process. The Criado method, Coats-Redfern Method, and Direct Differential methods were used to model the kinetics, with the latter two methods providing a closer fit with the experimental data. The kinetics of thermal degradation were separately studied for three temperature zones represented as drying, active, and passive zones. The results of Coats-Redfern and Direct Differential methods showed that (i) the nth-order reaction model is applicable for all the samples with order of reaction in the active zone being around ~ 2.0–3.0, ~ 2.5–3.0, and ~ 3.0 for MH, CS, and GNS, respectively, and (ii) the D-3 model is applicable for all the samples in the passive zone.
... The results show that the ignition temperature (T i ), the peak temperature (T m ), and the burnout temperature (T f ) tend to be delayed towards high temperature with increasing heating rates due to thermal conductivity. The increasing thermal conductivity leads to an increase in the burning rate (Ma et al. 2017); therefore, the higher temperature difference between the inside and outside of the samples, the decomposition would be faster and the combustion temperature would be higher in the same combustion stage, which is similar to the results of previous studies (Maiti et al. 2007;Zhu et al. 2019). As shown in Table 5, the comprehensive combustion characteristic index S of the same sample increases with the increase of the heating rate β. ...
A key factor restricting the application of biochar in the steel industry is its high-quality upgrading. This paper evaluated the characteristics of hydrochar produced by HTC (hydrothermal carbonization) process of corncob to be used as a solid fuel. HTC temperatures (240–300 °C) and HTC water-reused times (1–3 times) were examined for their effects on hydrochar yield, physicochemical characteristics, and combustion properties. The results showed hydrochar yields, O/C, and H/C parameters decreased as HTC temperature and water-reused times increased, while its high heating value increased. Due to dehydration and decarboxylation, hydrochar showed similar characteristics to those in bituminous coal. The removal efficiency of alkali metal K reached 99% after HTC treatment. Carbonaceous hydrochar had become more compact, orderly, and stable with increasing amounts of aromatic functional groups, C = C, and C = O. Hydrochar, as a biofuel, has higher ignition energy and is more stable than corncob due to its high carbonaceous order degree. To calculate combustion kinetic parameters, the Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) methods were applied. The results revealed that Eα (average activation energy) was quite similar between the two models. HC-300 had an Eα of 262 kJ/mol. HTC could be an efficient way to reutilize corncob biomass into clean biofuels with high calorific value.
... Active pyrolysis occurred in stage II, because of the breakdown of cellulose and hemicellulose, it resulted in the greatest weight reduction (Mian et al., 2019). Stage III, which usually occurs at very high temperatures and at slower rates, is associated with lignin decomposition (Maiti et al., 2007;Naik et al., 2010;Nhuchhen & Basu, 2014). Increasing the heating rate from 10 to 25 °C/min caused the DTG curves to shift to the right. ...
Pyrolysis is a very fast and effective thermochemical conversion scheme, hence suitable for the processing of elephant grass, a fast-growing and invasive grass, into bioenergy. This research investigates the pyrolysis characteristics and the thermal degradation of elephant grass using thermogravimetric analysis (TGA). Different characterization techniques were carried out to study the biomass and its bio-oil in order to ascertain their fuel properties. The two most widely used iso-conversional methods, Flynn–Wall–Ozawa (FWO) and Kissinger– Akahira–Sunose (KAS), were used to analyze the TGA data obtained over a range of temperatures at heating rates of 10, 15, and 25 °C/min in order to calculate the activation energy and other thermodynamic parameters. From the pyrolysis study, the highest bio-oil
yield of 39 wt% was achieved at 500 °C. The obtained bio-oil has excellent fuel properties because of its higher heating value (HHV) of 20.9 MJ/kg, low ash and sulphur contents. The average activation energies ( Ea) were 172.48 kJ/mol and 164.11 kJ/mol, respectively, for the FWO and KAS methods, while the average enthalpy changes (ΔH) were 168.31 kJ/mol and 159.32 kJ/mol. These values of Ea and ΔH revealed that the overall reaction is favourable since their difference is less than 5 kJ/mol. FWO produces higher and more accurate results since it can capture the decomposition behaviour of the different biomass components for any conversion fraction, while KAS is based on the overall reaction.
... The little mass loss after 500 • C probably resulted from the decomposition of carbonaceous matters in char residues. Additionally, all the degradation peaks shifted to the higher temperature side with the increment of heating rates, which may be due to the increasing heat transfer resistance at higher heating rates [40]. Similar results have also been reported by others [41,42]. ...
Co-pyrolysis of lignocellulosic biomass and hydrogen-rich petroleum-based polyolefin plastics is a promising to way to improve bio-oil quality and alleviate the waste plastic pollution issues. In this study, co-pyrolysis of pinewood and HDPE was systematically investigated. The addition of HDPE decreased yield of char and gas while increased that of bio-oil, enhancing the selectivity to alcohols and hydrocarbons. The most obvious synergistic effect was observed at the HDPE mixing proportion of 0.25, at which hydrocarbon selectivity derived from co-pyrolysis experiments was 41.19% higher than the calculated weighted average values. As pyrolysis temperature increased from 500°C to 700°C, the yield of bio-oil from co-pyrolysis at the HDPE mixing proportion of 0.25 decreased from 69.11 wt.% to 50.33 wt.%, alkanes selectivity decreased from 27.41% to 3.67% and olefins selectivity increased from 14.96% to 47.12%. At 700°C, aromatics started to produce with a selectivity of 15.50%. The surface morphologies of char were not significantly affected by the HDPE mixing proportion and pyrolysis temperature. The thermogravimetric analysis results revealed that the global co-pyrolysis process can be divided into two major degradation stages, based on which multi-step method was adopted to analyze the kinetics of the process. The average apparent activation energies of stage I and stage II were 167.73 kJ/mol and 274.74 kJ/mol, respectively. The results from this work provide a theoretical guide for further development of co-pyrolysis of pinewood and high-density polyethylene (HDPE).
... Most of the published papers on mustard-based biomass are related to agronomic and environmental applications, but limited literature is available to explain the effect of parameters on the synthesis of various mustard stalk and husk based bioproducts. Malti et al. [43] examined the physicochemical properties and pyrolysis kinetics of mustard straw and husk using multiple linear regression analysis. For the intent of producing biofuel, the thermal degrading behavior of mustard straw biomass and the optimization of the pyrolysis process factors were examined by Nawaz et al. [42]. ...
Biomass and biochar has recently been the subject of extensive investigation since they offer various advantages for many engineering problems. The synthesis of biochar from biomass depends both on the nature of feed as well as on the production procedure adopted. As a result, there is an extensive research gap available to obtain the optimum condition for evaluating a comprehensive roadmap for producing biochar. The present work explores the designing and optimization of four parameters, namely pyrolysis temperature, time, heating rate, and gas flow rates for the production of mustard straw biochar (MSB) through slow pyrolysis under the inert atmospheres of nitrogen (N2) and carbon dioxide (CO2). Response Surfaces Methodology with full factorial Box-Behnken design (RSM-BBD) of trials were used to assess the impact of parameters and determine their optimum conditions. In order to maximize the impact on physio-chemical properties of MSB, the following range of parameters are taken; pyrolysis temperature (400-10000C), time (30–180 min), heating rate (3-70C/min), and gas flowrate (50–200 cc/min) and their responses are evaluated on mustard biochar yield, pH, and electrical conductivity (EC). Multiple responses optimization using the desirability function was applied under both environments. The prepared samples of MSB in N2 and CO2 environment (referred as MSBN and MSBC respectively) were characterized using CHNS, FE-SEM, XRD, FT-IR, and BET on the optimal response for MSB. Based on the results, it was observed that MSBC had a greater surface area and is more porous, due to which it offers higher potential in many real-world applications. The study showed that a stable and porous MSB can be obtained using pressured pyrolysis of biomass in a CO2 atmosphere. The present study’s findings can be the first to offer a better recipe for MSB production under various conditions using RSM-BBD, given that sharp discrepancies exist in biochar properties due to variations in the production conditions.
... In the context of TGA and DTG curves, the pyrolysis process with anascending temperature was divided into three stages: drying (0-200℃), main pyrolysis (200-450℃), and carbonization (450-800℃). Cattle manure had TGA plots similar to those of corn Residue (Fei Yu, et al., 2006), mustard straw and stalk (S. Maiti, et al., 2007), and microalgae (Peng W, et al., 2001). However, manimal manure in three stages had a temperature range that was different from other samples.. ...
Cattle manure is a biowaste with bioenergy recovery potential for heat and
power generation. However, there is less kinetics data available in literature
to date. In this work, a kinetic study of the pyrolysis process of cattle
manure is investigated through the use of thermogravimetric analyses. The
samples were heated over a range of temperature from 15 to 800 0C with
heating rates of 10 0C /min. The weight loss was measured by a
thermogravimetric analyser in an inert atmosphere. Experimental results
showed that an animal manure pyrolysis process can be divided into three
stages: dehydration, pyrolysis, and carbonization. These stages may produce
differed features on end residuum, weight loss rate, and peak features, as
indicated by thermogravimetric (TG) and derivative thermogravimetric
(DTG) curves. The thermal gravimetric (DTG) thermogram shows that the
highest reaction rate occurred at between 200 and 450 °C where the
devolatilisation process was initiated to overcome the activation energy
barrier of the manure. Results showed four steps for both the pyrolysis and
the combustion reactions, with the second step being the most critical one
and during which most thermal decomposition of cellulose, hemicelluloses,
starch and protein occurred.
... As illustrated in Figure 1c, the thermal events during the pyrolysis of MBACs can be divided into two stages: The first stage is dewatering and degassing. As the pyrolysis temperature is elevated from room temperature to 300 • C, the moisture, adsorbed volatile organic matter, and volatile nitrogen in MBACs are eliminated [40,41]. The MBACs exhibit a similar weight-loss ratio. ...
The effective utilization of charcoal and tar byproducts is a challenge for pyrolysis gasification of bamboo. Herein, the bamboo tar was modified via polymerization and acted as a new adhesive for the preparation of excellent bamboo-charcoal-derived molding activated carbon (MBAC). As compared with pristine tar and other adhesives, the aromatization of tar with phenol increased its molecular weight, oxygenic functional groups, and thermal stability, leading to the decreased blocking impact of charcoal pore and improved bonding and pyrolytic crosslinking effect between charcoal particles. These further contribute to the high mechanical strength, specific surface area, pore volume, and amount of oxygenic functional groups for fabricated MBAC. Owing to the high microporous volume of MBAC, it exhibited 385 mg·g−1 toluene and 75.2% tetrachloride gas adsorption performances. Moreover, the pseudo-first-order, pseudo-second-order, and Bangham models were used to evaluate the kinetic data. The toluene adsorption process conforms to the Bangham kinetic model, suggesting that the diffusion mechanism of toluene adsorption mainly followed intraparticle diffusion.
... The temperature of the material's inner core and the outer area remains identical at a slower heating rate. As the heating rate increased, the temperature difference between the outer and inner cores of the material increased [43]. Heat transfer time is another factor that may alter the thermal profile in response to a change in the heating rate. ...
... The first, occurring at lower temperatures, represents the decomposition of hemicellulose present in each material, and the second corresponds to the decomposition of cellulose. For the flat tailing section, lignin is responsible, which is known to decompose slowly over a broader temperature range [30,31]. ...
We report on the kinetics of pyrolysis of bark wood of four coniferous tree species: fir (Abies sibirica), larch (Larix sibirica), spruce (Picea obovata), and cedar (Pinus sibirica) denoted as FB, LB, SB, and CB, respectively. Thermogravimetry (TG) and differential scanning calorimetry (DSC) methods were used to study the influence of KCl and K3PO4 compounds on the process of thermal decomposition of fir bark and determine the main thermal effects accompanying this process. As a result of the studies carried out, it was found that KCl additives practically do not affect the decomposition of hemicelluloses, but they shift the maximum decomposition of the cellulose peak in the direction of decreasing temperature to 340.9 °C compared to untreated bark (357.5 °C). K3PO4 promotes the simultaneous decomposition of hemicelluloses and cellulose in the temperature range with a maximum of 277.8 °C. In both cases, the additions of KCl and K3PO4 reduce the maximum rate of weight loss, which leads to a higher yield of carbon residues: the yield of char from the original fir bark is 28.2%, in the presence of K3PO4 and KCl it is 52.6 and 65.0%, respectively. Using the thermogravimetric analysis in the inert atmosphere, the reaction mechanism has been established within the Criado model. It is shown that the LB, SB, and CB thermal decomposition can be described by a two-dimensional diffusion reaction (D2) in a wide range (up to 0.5) of conversion values followed by the reactions with orders of three (R3). The thermal decomposition of the FB occurs somewhat differently. The diffusion mechanism (D2) of the FB thermal decomposition continues until a conversion value of 0.6. As the temperature increases, the degradation of the FB sample tends to R3. It has been found by the thermogravimetric analysis that the higher cellulose content prevents the degradation of wood. The bark wood pyrolysis activation energy has been calculated within the Coats–Redfern and Arrhenius models. The activation energies obtained within these models agree well and can be used to understand the complexity of biomass decomposition.
... However, at a higher heating rate, the temperature distribution of the inner core and the surface along the biomass section is significantly different and therefore forms a thermal hysteresis. 25 As can be seen from Table 3, the T i and T max increased gradually with the increase of heating rate. For raw cornstalk, when the heating rate increased from 5 to 30°C/min, the T i increased from 173.8 to 223.2°C, and the T max increased from 313.0 to 342.9°C. ...
In this study, the effects of torrefaction pretreatment on physicochemical characteristics and pyrolysis behavior of cornstalk were investigated based on the changes in its chemical and structural characteristics. The results indicated that torrefaction treatment improved the fuel properties with elevated torrefaction temperature, including the lower volatile content, higher carbon content, and higher heating value. In addition, serious torrefaction promoted complete degradation of hemicellulose, while the lignin was increased obviously. The crystallinity degree of cornstalk increased first and then reduced with the torrefaction temperature. Slight torrefaction enhanced the devolatilization and thermochemical reactivity of cornstalk, but serious torrefaction discouraged the volatile release. Kinetic parameter analysis indicated that the Ozawa-Flynn-Wall model was more accurate in calculating the activation energy, and the average activation energy gradually increased from 196.06 to 199.21, 203.17, and 217.58 kJ/mol. Furthermore, the thermodynamic parameters also showed an increasing trend with elevated torrefaction temperature. These results provide important basic data support for the thermochemical conversion of cornstalk to energy and chemicals.
... It was also demonstrated that by increasing the heating rate, the total volume of volatile compounds increases, whereas decreasing the heating rate results in volatile compounds remaining in the reactor for a longer period of time. Therefore, the longer residence time favored the generation of secondary reactions like re-condensation, re-polymerization, and cracking reactions, all of which contribute to bio-char growth (Maiti et al., 2007). The small reduction in volatilization was attributed to mass and heat exchange constraints during the pyrolysis. ...
Non-isothermal co-pyrolysis of Delonix regia and tube waste was carried out using a thermogravimetric analyzer under nitrogen atmosphere at temperatures 25 to 1000 °C, with heating rates between 5 and 55 °C min⁻¹. The kinetic triplets were estimated using five iso-conversional models: Differential Friedman, Kissinger-Akahira-Sunose, Ozawa-Flynn-Wall, Starink, and Distributed Activation Energy Method. In kinetic analysis, the average activation energy (Eα, kJ mol⁻¹) and frequency factor (ko, min⁻¹) values were 230.47 and 2.55× 10³⁰; 208.13 and 8.31× 10²⁶; 207.78 and 1.58× 10²⁴; 208.38 and 6.47× 10²⁶; 208.13 and 5.15× 10²⁶; respectively. In thermodynamic analysis, average values of ΔH, (kJ mol⁻¹), and ΔG, (kJ mol⁻¹) were 225.38, 179.9; 225.28, 180.22; 225.18, 180.31; 225.08, 180.99; and 224.98, 182.15; respectively. Criado's master plot revealed a multistep reaction mechanism for the co-feed.
... An increase in the release of total volatiles was noticed with the increase in the heating rates, which can be associated with the favoring of cracking reactions at higher heating rates. Cracking reactions facilitate in the release of lighter hydrocarbons at temperatures above 600 • C and result in an additional mass loss as compared to low-heating rates (Maiti et al., 2007). The addition of NZ material to the DSW and DSM samples facilitated in an early onset of pyrolysis process (see supplementary material). ...
This study investigated the potential application of anaerobically digested residues for generating bioenergy in the presence of alkali bifunctional material, sodium zirconate (Na2ZrO3, NZ) using a thermogravimetric analyzer connected to a mass spectrometer. Isoconversional kinetic models, compensation effect and master-plots method were used on data obtained under multiple heating rates (10, 15 and 20°C min⁻¹) to calculate the activation energy (Eα) and pre-exponential value (A) and reaction mechanism. The average Eα for blend samples C-DSW (NZ mixed with digested municipal solid waste (DSW)), and C-DSM (NZ mixed with digested swine manure (DSM)) were 172.24 and 171.63 kJ mol⁻¹, which were much lower when compared to plain samples, DSW (202.51 kJ mol⁻¹) and DSM (215.22 kJ mol⁻¹). The total gas yields increased by 19.5 and 17.1% for NZ blended samples C-DSW and C-DSM, respectively. In addition, the hydrogen yields also increased by 79 and 44% for C-DSW and C-DSM, respectively.
... MS contain high glucosinolate because of which it less preferred as a cattle feed. Therefore, effective management of mustard stalk becomes necessary for energy recovery through thermal processing such as pyrolysis technique (Maiti et al., 2007). The present study investigates the thermokinetic properties of the MS to evaluate its bioenergy potential. ...
Mustard stalk (MS) was investigated for its thermal degradation and kinetics using thermogravimetric analysis (TGA) at 30 to 900 °C at four different heating rates (10, 20, 30, and 40 °C.min⁻¹). Kinetic and thermodynamic parameters were determined within the active pyrolysis zone using three non-isothermal models viz. Flynn-Wall-Ozawa; Kissinger-Akahira-Sunose; and Starink method. The results indicate that MS undergoes thermal degradation experiencing different stages of mass loss like dehydration, active pyrolysis, and passive pyrolysis as main stages. The active pyrolysis stage resulted in maximum mass loss. The average activation energy (Eα) was 173.83; 173.18 and 172.94 kJ.mol⁻¹ determined using FWO, KAS, and Starink model, whereas the average pre-exponential factor (A) was 2.22 × 10¹⁷, 3.21 × 1017, and 2.92 × 10¹⁷ respectively. Change in enthalpy (ΔH*), Gibbs free energy (ΔG*), and entropy (ΔS*) determined were in good agreement for all three methods.
... Uniform temperature across the solid mass could be achieved at a lower heating rate as an enough time was available for heating, but it could enhance the char formation via secondary reactions and more thermal cracking of pyrolysis volatiles into non-condensable gases. Whereas, at the higher heating rates, a temperature gradient across the solid mass could be responsible for this temperature shift [30], but increase in rate of decomposition with the heating rate observed because of higher thermal energy at higher heating rate [31] and the secondary reactions might change with the heating rate [32]. Therefore, TGA results suggest that higher heating rate with low residence time of volatiles is desirable in fast co-pyrolysis reactor to produce high yield of bio-oil. ...
Unprecedented growth in mixed plastic and biomass wastes such as plastic bags, drinking water bottles, agro- and-forestry-waste, along with COVID-19 driven waste (facemask, gloves, PPE kits, surgical masks) have obliged the scientific community to look for technologies that can process and convert both biomass and plastic wastes together into useful end-products. The co-pyrolysis of biomass and plastic would be promising as it may produce a high-quality liquid fuel (hydrocarbon-rich bio-oil) because of the synergy between the two reactants. Notably, the addition of catalysts in a co-pyrolysis process facilitates multiple parallel reactions such as depolymerization, dehydration, deoxygenation, hydrogenation, hydrodeoxygenation, aromatization, and condensation. As a result, hydrocarbon-rich bio-oil, suitable for direct use/blend in the existing fuel, is produced. This review critically discussed the progress and opportunities of co-pyrolysis for the processing of biomass and plastics wastes. Synergistic effects of biomass and plastic during co-pyrolysis, with and without catalyst, are discussed and correlated with the final product yields. Several commercial, naturally occurring metal salts, and anthropogenic catalysts affecting bio-oil yield and composition are reviewed. The mechanistic insight into biomass/plastic thermal decomposition is presented and compared with those under the catalytic environment. Finally, the process parameters and techno-economic analysis of the biomass and plastic co-pyrolysis, including COVID-19 waste handling, are discussed. Co-pyrolysis advised as a promising route for biomass and COVID-19 waste processing and hence management.
... Mustard biomass is a potential source of biofuel and attracted interest due to its sizeable calorific value compared with other agro feedstocks (Sanjid et al., 2014). The pyrolysis of mustard biomass has shown degradation up to 60% in a wide heating rate of 5-50 • C/min (Maiti et al., 2007). The thermal decomposition behavior of mustard biomass is required for optimizing the process parameters and reactor design in large-scale pyrolysis (Hacking et al., 2020). ...
Mustard waste briquettes are commercially used as a fuel for power production in boilers, whereas the thermal kinetics of the biomass plays a vital role in deciding the process parameters. The pyrolysis process converts biomass to value-added products such as biochar, bio-oil, and hydrocarbon gases based on the heating rates and temperature. To enhance the pyrolytic activity of mustard biomass, magnetically separable and reusable FeNi alloy catalyst is investigated. The thermo-conversion properties are studied under variable heating rates with 2 and 10% FeNi particles prepared through a facile chemical reduction technique. Thermal kinetics is computed using Flynn-Wall-Ozawa (FOW) and Kissinger-Akahira-Sunose (KAS) methods. The activation energies calculated using FOW and KAS methods increase with FeNi addition in mustard while the calorific value decreases. The FeNi alloy particles with the spike-like morphology provide better metal-biomass binding resulting in higher activation energy and facilitates the easy decomposition of lignin. The 10% FeNi mustard shows uniform conversion independent of heating rates, suitable for magnetically recoverable catalytic pyrolysis. Response surface methodology analysis predicts optimum conversion for 10% FeNi added mustard and less significance for the heating rates concurrence with the experiments. Artificial neural network utilized to predict and validate mass loss for mustard biomass exhibits best fit for the three neural hidden layer and one output layered topology.
... can also be incorporated with the fact that with the increase in heating rates, the difference in the temperature of the inner and the outer surface of the biomass increases because less residence time is available for the process of devolatilization which in turn results in thermal lag; hence, this shift in DTG curve was observed [42]. Lower heating rate provide sufficient residence time and results in better heat transfer in the biomass particles and also favor secondary reactions which result in char formation [43]. ...
The present research aims towards the study of thermal degradation kinetics and thermodynamics of Arachis hypogaea shells (AHS) to evaluate its potential for bioenergy production. Physicochemical characterization, i.e., proximate, ultimate, compositional analysis, and higher heating value (HHV) were carried out in addition to thermogravimetric (TG) analysis. Physicochemical characterization revealed high volatile matter (75.2 wt.%) with considerably lower moisture, ash contents, and significantly higher HHV (17 MJ/kg). TG analysis of AHS was conducted from ambient to 800 °C at multiple heating rates (10, 15, and 25 °C/min) using nitrogen as carrier gas. TG and derivative thermogravimetric (DTG) analysis disclosed that the maximum degradation occurs in the temperature ranging from 150 to 450 °C (~64%). The iso-conversional methods that were employed to determine kinetic and thermodynamic parameters are Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), Starink, and Friedman. Average values of activation energies as calculated by these models were 175.05, 173.65, 171.83, 175.95 kJ/mol respectively. The values of pre-exponential factor (A0) lie in the magnitude of 109–1020 s−1. The calculated average values of Gibbs free energy (ΔG) by FWO, KAS, Starink, and Friedman were 154.61, 154.66, 154.70, 154.63 kJ/mol, respectively. The average change in enthalpy (ΔH) and change in entropy (ΔS) for the degradation process were in between 166.54–170.65 kJ/mol and 19.99–27.05 J/mol.K, respectively. Reaction mechanism estimation was done using the Z-plot method associated with the Criado method which confirmed that thermal degradation of AHS follows multiple reaction mechanisms. The results suggest that AHS has the potential to be effectively used for the generation of bioenergy.
... It was also proven that by enlarging heating rate, the total volume of volatile compounds augmented while at a lower rate of heating, volatile were retained longer in the reactor. Thus, the longer residence time favoured the creation of secondary reactions such as cracking, re-polymerization, and re-condensation, which further directs to a growth of biochar [31]. The slight reduction of volatilization was credited to heat and mass exchange limitation during pyrolysis. ...
A substantial amount of renewable feedstocks study has been dedicated to bio-fuel and biochemical generation, preferably thermochemical conversion processes such as pyrolysis. In this work, the physicochemical study, pyrolysis behaviouer and kinetic factors of Cascabela thevetia (SK) Delonix regia (SG) and Manilkara zapota (CK) seeds were tested in the thermogravimetric analysis (TGA) at three rates of heating (10 - 50 oC min⁻¹) to estimate its bioenergy potential. Further, the kinetic constraints were investigated by using model-free approaches, namely Kissinger-Akahira Sunose (KAS), Friedman model (FM), Cots-Redfern model (CR), Distributed Activation Energy Model (DAEM), Ozawa-Flynn-Wall (OFW), and Vyazovkin method (VZ). Characterization study of applied biomass showed attendance of extensive amount of volatile matter (73.15-75.24 %), carbon content (50.12-55.02 %), heating value (20.52-25.12 MJ kg⁻¹), and lower ash content (2.20-3.15 %) and nitrogen content (3.01-5.10 %). Further, DSC inspection of applied biomass recognized that biomass decayed under the endothermic process during the heating process. The average activation energy for CK, SG, and SK was originated to be 157.81, 150.90, 166.28 kJ mol⁻¹ for KAS, 164.55, 166.59, 177.05 kJ mol⁻¹ for OFW, 168.47, 166.05, 185.22 kJ mol⁻¹ for FM, 194.87, 157.87, 199.74 kJ mol⁻¹ for DEAM and 168.75, 158.86, 102.28 kJ mol⁻¹ for VZ respectively. Additionally, CR model yields 49.99, 35, 38.71 kJ mol⁻¹ at n=1 and 34.79, 29.18, 27.7 kJ mol⁻¹ at n ≠1 for CK, SG, and SK, respectively. Finally, the variance between activation energy and enthalpy of reaction showed promising product formation. In contrast, Gibbs free energy and higher heating value (HHV) of biomass exhibited its potential for energy and fuel production.
... It is further explained that the drastic change in heat transfer trend occurring in the samples at higher heating rates is due to the disparity in heat flow across the cross-section. The disparity in heat flow across the cross-section is due to the poor conductivity in biomass however these barriers can be overcome with high heat and mass transfer coefficients [44,45]. A detailed result for each heating rates are shown in Table 3. ...
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Synergistic effects and kinetic parameters for binary mixtures of corn cob and high-density polyethylene (HDPE) in co-pyrolysis with the presence of renewable chicken and duck eggshell catalyst are evaluated using thermogravimetric analysis (TGA) approach at various heating rates (10-200 K/min) in temperature range of 323-1173 K. Weight average global process model based on two-stage kinetic scheme are employed in this study. The reaction mechanisms involved in the co-pyrolysis process are 1-D diffusion for second stage of thermal degradation and 3-D diffusion for third stage of the thermal degradation. The difference in the experimental and estimated values of the catalytic corn cob and HDPE mixtures in terms of weight loss indicates the existence of the synergistic effects during the pyrolysis process. The values of the activation energy for pure corn cob, pure HDPE, binary mixtures of corn cob and HDPE are reported in the range of 43.61-83.03, 412.32-510.72, and 28.98-93.18 kJ/mol, respectively. Meanwhile, the activation energy for catalytic pyrolysis process are in the range of 28.98-113.17 and 23.65-119.50 kJ/mol respectively in the presence of chicken and duck eggshells as catalyst. Additionally, artificial neural network (ANN) and joint optimization modelling are also utilized to validate and optimize the results from the TGA.
... The TGA profiles depict the trend of mass loss occurring in the sample with time when heated in the temperature range of 30-200 °C, this weight loss is due to the dehydration of the MS sample. 19 Loss of unbound moisture resulted in an 11.08 % decrease in weight in the above temperature range. This value bears a close resemblance to the moisture percentage of the MS (Table II). ...
Present work is focused on the preparation of mustard stalk activated carbon (MSAC) using chemical activation with H3PO4 and exploring its properties for its use in dye removal from wastewater. Adsorption variable (dosage, contact time, and solution pH), pore structure, morphology, surface functional groups, equilibrium kinetics, and isotherm study for removal of methylene blue (MB) using MSAC were investigated. The present study showed that an adsorption dosage of 0.2 g L-1 and pH 8 can be considered as optimum for the MB removal. SEM result showed that pore of MSAC was larger than the pore of the mustard stalk (MS). BET surface area and total pore volume of MSAC were found as 510 m2 g-1 and 0.33 cm3 g-1, respectively. Equilibrium adsorption data were examined by Langmuir and Freundlich isotherm models. Better correspondence to the Langmuir model with a maximum adsorption capacity of 212.76 mg g-1 (MB onto MSAC) was obtained. Dimensionless factor, RL revealed favourable nature of the sorption in the MSAC - MB system. Adsorption rates were found to conform to the pseudo-second-order kinetics with good correlation. These results show that the MSAC could be used as a renewable and economical alternative to commercial AC in the removal of MB dye from wastewater.
... The mustard waste biomass has been chosen owing to the widespread cultivation of mustard oil seeds in India and its higher cellulosic content than other agro wastes like rice straw and wheat bran. [19]. Mustard straw and stalk (MSS) constitute 70% of the mustard plant. ...
This study focusses mainly on assessing the effectiveness of acetone organosolv process as a pretreatment strategy on mustard (Brassica juncea) biomass. We used aqueous acetone as the solvent and sulfuric acid as a catalyst for ease of cellulosic saccharification. The acetone organosolv pretreatment of mustard straw and stalk (MSS) biomass was investigated for the effect of acetone concentration (SC), acid catalyst concentration (AC), and treatment duration (t) using a full factorial design of the experiment and subsequent Pareto analysis of their effects. The 23 full factorials design contained 12 runs, each of which was deployed to pretreat weighed amount of MSS biomass. Each of the different products of these 12 runs was further saccharified using cellulase enzyme produced by Trichoderma reesei. Among the variables, the time has a pronounced effect during pretreatment on glucose yield. Since the increase in time from 30 to 90 min caused an increase of 3.39 g/L in glucose concentration, the increase in acid catalyst concentration from 0.2 to 0.4% caused an increment of 0.7 g/L in glucose content, while the rise in acetone concentration from 50 to 80% caused an increment of 0.44 g/L in glucose concentration. The reducing sugars generated after hydrolysis of MSS biomass can be utilised for the production of bioethanol by Saccharomyces cerevisiae. The FTIR data and SEM studies of untreated and treated MSS biomass were performed to indicate the pretreatment of the MSS biomass. Therefore, after pretreatment MSS biomass can be an alternative substrate for bioethanol production. This study is an attempt to promote the valorization of widely available MSS biomass for bioethanol production by using a statistically optimized process.
... Thus with an increase in heating rate, there is an increase in total volatile products, whereas, with a decrease in heating rate, there is an increase in residence time favoring the secondary reactions. These secondary reactions include cracking, re-condensation, and re-polymerization leading to char production [50,53]. For different heating rates the T max is found to be 350.62°C, ...
The pyrolytic kinetics of waste motor oil (WMO) based on various differential and integral based model-free methods is studied utilizing the data obtained from TGA. For the different heating rates, i.e., 5 °C/min, 10 °C/min, and 40 °C/min the overall volatile conversion was found to be > 90%. The calculation of activation energy is performed using four different models (a) Friedman (b) Kissinger-Akahira-Sunnose (c) Flynn-Wall-Ozawa and (d) Starink methods. The mean activation energy was found to be 139.863 kJ/mol, which has been later used for the determination of z(α) master plots. Moreover, the prediction of the reaction model has been made by analyzing the different theoretical and experimental z(α) master plots. Further, the unknown parameters of the Sestak & Berggrens’s model are obtained using the model fitting methods in MATLAB. The obtained reaction model is fα=dαdt=3.21x1010βe-139863RT(1-α)3.049α-6.994-ln1-α5.626 which followed the autocatalytic (sigmoidal) mechanism. Furthermore, the thermodynamic stability of the system had been determined by calculating the change in entropy, enthalpy and Gibbs free energy. The kinetic parameters along with the thermodynamic results recommend a highly reactive system feasible for waste to energy generation using pyrolysis.
... White mustard (Sinapis alba L.) is an annual herbaceous plant from the Brassicaceae, native to the Mediterranean and the Near East regions but has been introduced into America and other parts of Eurasia (Vaughan and Hemingway 1959). At present, this plant is cultivated overall the world to be used for nutritional, industrial, and medicinal applications and also is utilized as a green manure (Maiti et al. 2007). Members of Brassicaceae, e.g., white mustard produce root systems which grow faster and deeper than Poaceae (Hajzler et al. 2012). ...
Introducing zinc (Zn) biofortified vegetables capable to thrive on Zn-polluted soils might simultaneously solve both the problems of dietary Zn deficiency and environmental Zn pollution. White mustard (Sinapis alba L.) is known to thrive on soils with high Zn concentrations, thus we aimed to determine to what extent it has physiological characteristics close to known Zn hyperaccumulators for possible use of this species in phytoremediation efforts and production of Zn-biofortified crops. To achieve this, in a pot experiment plants were grown for 7 weeks in soils with normal (25.5 mg kg−1) and excess (500 and 1000 mg kg−1) Zn concentrations and assessed for metal accumulation, enrichment, translocation and tolerance. Zn accumulated mainly in shoots (861 mg kg−1) with translocation factor of 2.5 in parallel with enhanced root H+-ATPase activity but the plant Zn bioconcentration factors were less than one. Excess soil Zn increased plant biomass and activities of some reactive oxygen species scavenging enzymes without any effects on root lipid peroxidation or leaf chlorophyll contents. Despite lack of criteria for a true Zn hyperaccumulator, white mustard exhibited significant Zn trans-location capacity with tolerance to toxic Zn concentrations in tissues as reflected from its efficient antioxidant metabolism, unaltered photosynthetic pigments under excess Zn and high aboveground biomass similar to some Zn hyperaccmulators. Accordingly, the cultivation of this species has the dual advantages of phytoremediating Zn-contaminated soils and producing Zn-biofortified vegetables.
The primary focus of the twenty‐first century has been on developing new and cleaner fuels from renewable sources. The increasing availability of renewable energy sources in environment, such as lignocellulosic biomass derived from agricultural and forest residues, has created a plethora of opportunities for biofuel production. For this purpose, the search for appropriate waste biomass source and the design of suitable reactors are very essential, where the latter requires the knowledge of kinetic triplets. These requirements paved the way to the novelty of the present work as a selection of a rarely used biomass source, that is, Peltophorum pterocarpum , and its non‐isothermal thermogravimetric analysis for the evaluation of kinetic triplet of the process. The range of temperature is 298–1173 K attained at heating rates of 10–55 K min ⁻¹ . Kinetics were estimated using differential Friedman method (DFM), distributed activation energy method (DAEM), Ozawa–Flynn–Wall (OFW), Kissinger–Akahira–Sunose (KAS), and Starink (STK) models. Mean activation energy (kJ mol ⁻¹ ) and pre‐exponential factor (min ⁻¹ ) of pyrolysis process by five models were 183.68 and 1.24 × 10 ¹⁷ for DAEM, 194.28 and 3.08 × 10 ²¹ for DFM, 183.68 and 4.40 × 10 ¹⁶ for KAS, 184.12 and 2.12 × 10 ¹⁴ for OFW, and 183.93 and 3.56 × 10 ¹⁶ for STK. Average values of changes in Gibbs free energy, enthalpy, and entropy by five models are 174 kJ mol ⁻¹ , 178 kJ mol ⁻¹ , and 0.007 kJ mol ⁻¹ K ⁻¹ , respectively. Criado's master plots revealed distinct reaction pathways during the process for different conversion levels.
Organic additives are used for pellet forming in the manufacturing process of MOX fuels. In order to understand their degradation during the sintering process, the thermal decomposition of oxamide has been investigated using thermogravimetric analysis. The temperature range of experiments was 30–1000 °C, and 1, 2, and 5 °C.min⁻¹ heating rates were used. The apparatus was under a constant flow of argon mixed with 4 vol% of dihydrogen. The kinetic parameters were found to be E=100±7kJ.mol−1,A=2.5*108min−1 and n=0.32 using Friedman's isoconversional method. With the kinetic triplet, a predictive model of the thermal decomposition of oxamide was established by integrating the conversion rate in non-isothermal conditions. The model calculations were compared to experimental data, and the results were deemed satisfactory. This study is helpful to understand the degradation process taking place in the sintering furnace and constitutes a first step in the decorrelation of the effect of thermolysis and that of radiolysis on the organic additives used for MOX fuel pellets manufacturing.
Co-pyrolysis of biomass with waste tire, a hydrogen-rich material, can both improve the quality of bio-oil and mitigate the environmental issue caused by the disposal of waste tires. In this study, co-pyrolysis of corn stover and waste tire was firstly performed in a micro pyrolyzer, and positive synergistic effects were observed, promoting the production of hydrocarbon compounds. Additionally, the kinetics of co-pyrolysis of corn stover and waste tire were investigated. Due to the complexities of the co-pyrolysis process, the global process was divided into reactions of seven pseudo-components using the Fraser-Suzuki deconvolution function. The deconvolution results presented a good fit with experimental results. The activation energy of each pseudo-component was calculated using Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), and Friedman methods. Activation energy of each pseudo-component calculated from above mentioned methods did not greatly varied. Pseudo-component additives in waste tire with low thermal stability had the lowest activation energy (118.21-127.10 kJ/mol), and lignin in corn stover and synthetic rubbers (SR) in waste tire showed high activation energies since they are more thermally stable. The reaction mechanism was then determined using the master plot method. The results of the study are expected to provide more accurate basic information for further scale-up of the co-pyrolysis process.
A study on kinetic analysis of Bengal gram stalk (BGS), an agricultural waste biomass, was carried out using thermogravimetric analyser in an inert atmosphere. Thermogravimetric (TG) and Derivative thermogravimetric (DTG) curves were obtained by varying heating rates at 10°C.min −1 , 20°C.min −1 , 30°C.min −1 , and 40°C.min −1. Three iso-conversional methods viz. Flynn-Ozawa-Wall, Kissinger-Akahira-Sunose, and Starink were applied to determine the kinetic properties and simultaneously obtained the effective activation energies for BGS pyrolysis. The average activation energy (Eα) calculated for BGS was 113.37 kJ.mol-1 for FWO; 109.47 kJ.mol-1 for KAS, and 112.36 kJ.mol-1 for Starink method, respectively. The results showed that the effective activation energies for the pyrolysis of BGS varied with the degree of conversion (α) in the range of 0.1 to 1.0. The experimental analysis revealed the correlation between activation energy and conversion factor.
In recent years, lignocellulosic biomass has gotten a lot of coverage, especially for the captured energy through the anaerobic degradation. The conversion of lignocellulosic biomass to biogas through an anaerobic digestion process has been facing challenges such as low biogas production, low buffering ability, poor end quality of products, and potential heterogeneity of biomass which have difficulties to define an optimized unit operation. These deficiencies may be related to the recalcitrant disposition of agricultural wastes or low mass transfer. India has a large amount of lignocellulosic biomass, and this biomass remains unused in the harvested field. However, it has a scope of utilization by conversion into useful biofuel.
Furthermore, it could be enhanced the farmer's income as well as helps to contribute reduce the loss of environmental impact. Hence, the present review script discusses the potential, composition, biomethane production, pretreatment methods and technology related to lignocellulosic biomass, challenges, progress, and the latest program initiated in India. However, only 10 major types of lignocellulosic biomass have been reviewed in this paper.
Co-pyrolysis of biomass and plastics is a promising way to produce high-quality liquid fuel, and the knowledge on its kinetic and thermodynamic behaviors is crucial for designing an efficient reactor system. In this study, kinetic triplets and major thermodynamic parameters of both non-catalytic and catalytic co-pyrolysis of pine wood and high-density polyethylene (HDPE) were evaluated. Due to the complexity of co-pyrolysis process, Fraser-Suzuki function was adopted to deconvolute the derivative thermogravimetric (DTG) curves into four pseudo-components; namely pseudo- cellulose, hemicellulose, lignin and HDPE. For non-catalytic co-pyrolysis, average apparent activation energy of pseudo-hemicellulose, cellulose, lignin and HDPE were 137.12, 166.81, 227.2, 246.56 kJ/mol, respectively. The presence of HZSM-5 decreased both activation energy and pre-exponential factor and affected reaction mechanisms of each component. The activation energy of HDPE decreased by about 35% after addition of catalyst. The thermodynamic analyses revealed that external energy was required for all components to form activated complex, and this process was favored by addition of catalyst HZSM-5. Results obtained in this work are expected to provide more precise fundamental information for further scale-up of co-pyrolysis process.
The present study on one non-edible oilseed (Mesua ferrea L) employs the pyrolysis process to understand the pyrolysate composition and the thermal degradation behavior of biomass. The physicochemical characterization of whole seed was investigated using thermogravimetric analysis at different heating rates (5, 10, 20, and 40 °C min⁻¹), bomb calorimeter, proximate/ultimate analysis. FTIR analysis confirmed the presence of the lignocellulosic compounds. Kinetic analysis of biomass was investigated using iso-conversional models such as Friedman, Kissinger-Akhaira-Sunose, Ozawa-Flynn-Wall, Starink, Distributed Activation Energy model, and Avrami model. Further, composition analysis of the pyrolytic vapor was analyzed using analytical fast pyrolysis coupled with gas chromatogram/mass spectrometer (Py-GC/MS) at 400, 500, 600 °C. This study confirmed that alkenes were major pyrolysates, followed by alkanes and esters. The current investigation suggested that Mesua ferrea L whole seed can be converted to valuable chemicals using pyrolysis.
The present study is focused on the physicochemical characterization and thermal degradation studies of waste bio-oils. The study of bio-oil kinetics was executed in a thermogravimetric analyzer (TGA), using Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW), Friedman (FM), Starink (ST), Cots-Redfern model (CR), and master plot method. Detailed characterization of the bio-oil was carried out by using elemental analysis, examining ash content, viscosity, cold properties, heating value, moisture content, FTIR, GC–MS, and acidity. The results of the physicochemical investigations of bio-oil revealed significant carbon content (67.70%), higher heating value (26.12 MJ kg⁻¹), lower moisture (0.09%), and ash content (1.57%). The kinetic results underscore multi-step reactions and apparent activation energy that increases with progressive conversion. FTIR study established the occurrence of water, alkenes, acids, aromatics, and oxygenated products, whereas the GC–MS study confirmed higher hydrocarbon (14.20%) and lower oxygenated product in BO-1 compared to BO-2.
This work aims at studying the thermal behavior of a group of semi-interpenetrating polymer network (SIPN) membranes used as a base of proton conductive polymeric membrane for Fuel Cells. SIPNDX membranes were obtained from the cure reaction of diglycidyl ether of bisphenol A (DGEBA) and 4.4'diaminodiphenyl-sulphone (DDS) in the presence of polyethyleneimine (PEI) in different concentrations. All samples were analyzed in a thermogravimetric analyzer (303–973 K) under nitrogen flow and heating rates at 5, 10, 15, and 20 K min−1. The classical isoconversional models of Ozawa–Flynn–Wall (OFW) and Kissenger–Akahira–Sunose (KAS) were used to obtain the kinetic parameters, activation energy (Ea), and pre-exponential factor (A). We used the Coats-Redfern model and the Criado masterplot procedure to determine the best fitting reaction mechanism. This approach showed that for DGEBA/DDS network and SIPNDX samples, with up to 40 mass % PEI, the chemical reaction mechanism (F2). For higher PEI contents, SIPND50, diffusion-related models (D1 and R2), gave the most relevant mechanisms. Atomic force microscopy (AFM) images correlated with kinetic analysis endorses that in the SIPND50 the degradation reaction progress from the interface to the center of the phase, more reactive than the bulk. These SIPNs showed good potential as a solid electrolyte in fuel cells based on the thermal properties.
In this study, the pyrolysis characteristics of Karamay transformer oil are studied using Thermogravimetry (TG), Fourier Transform Infrared (FTIR), and Pyrolysis Gas Chromatography and Mass Spectrometry (Py-GC/MS) analysis. Four model-free methods of Friedman, Starink, KAS, FWO and one model-fitting method of Multivar-NLR are applied to determine the pyrolysis kinetics. The results show that the apparent activation energy varies less than 10% from 0.05 to 0.95 conversion rate regardless of the calculation method, and the average value is 40.24 kJ/mol, which is close to that of diesel, 35.82 kJ/mol. The best-fit kinetic model for characterizing the pyrolysis of transformer oil is the order-based kinetic model of f(α) = (1 − α)0.46 where the pyrolysis reaction rate is a function of the concentration of remaining reactants. The results of FTIR indicate that there is a large amount of alkanes with a higher number of carbon atoms and a small amount of aromatic hydrocarbons in the original transformer oil, while no unsaturated carbon has been identified. Consequently, the pyrolysis of transformer oil produces organic products including the n-alkanes, branched-chain alkanes, olefins, alcohols and phenols. Through Py-GC/MS analysis, n-alkanes are identified as the major group of volatile products by mass. The yields of n-alkanes are quantified using the external standard method in Py-GC/MS analysis where the results show that Karamay transformer oil presents the characteristic of “single peak with odd carbon predominance”, consistent with the characteristic of the recent sediments in China. The total yield of n-alkanes is 0.55 ± 0.06 g/g with n-heptadecane (C17) as the primary volatile product. The n-alkanes yield of transformer oil is higher than that of gasoline, 0.41 g/g and similar to that of diesel, 0.52 g/g. The dominating heavy components of Karamay transformer oil have higher carbon numbers than those of crude oils in other areas of the world. The current research provides theoretical and experimental basis for either direct use or further refinement of transformer oil into environmentally friendlier alternatives.
Present work is devoted to the study of independent operating parameters namely torrefaction temperature (TT), residence (torrefaction) time (RT), and heating rate (HR) on the slow pyrolysis or torrefaction of an important agro residue namely mustard stalk (MS). Response surface methodology along with three-factor and three-level Box-Behnken design is applied to find the effect of above mentioned three parameters on the higher heating value, energy yield, and fixed carbon of the torrefied MS. Experimentation and modeling analysis reveal that the effect of these three factors' responses follows the sequence: (TT) > (RT) > (HR). Also, the experimental data were analyzed using analysis of variance and fitted to a second-order polynomial model applying multiple regression analysis. Predictive models were obtained which were able to satisfactorily fit the experimental data, with the coefficient of determination (R²) values higher than 0.95. Derringer’s desirability function methodology was used for the optimization study which showed that the HHV, EY, and FC at optimum condition TT 300°C, RT 20 min, HR 5 oC/min were obtained as 21.26 MJ/kg, 81.26 %, and 35.38wt %, respectively for MS. Torrefied MS, as compared to raw MS, showed better solid fuel properties for co-combustion with coal and gasification. The experimental values closely agree with the corresponding predicted values. The functional behavior of raw and torrefied MS was studied by Fourier Transform Infra-Red Spectrometry.
Biomass pelletization technology has recently gained significant interest, where pyrolyzed pellets have a very wide range of applications (e.g., as pellet fuels and adsorbents). In this study, furfural residue pellets (FRPs) were pyrolyzed at temperatures of 200–850 °C in a tube furnace. The physical and chemical properties of the pyrolyzed FRPs (PFRPs) obtained at various temperatures were compared, and the kinetic parameters of the pyrolysis process were calculated using the distributed activation energy model (DAEM). The PFRPs prepared at 450, 650, and 850 °C had higher volumetric energy densities than coal, whereas other properties (e.g., H/C and O/C ratios) were found to be similar to those of coal. The maximum iodine adsorption value (i.e. 317.8 mg/g) and methylene blue adsorption value (i.e. 96.4 mg/g) were achieved by pyrolysis at 650 °C and 450 °C, respectively, indicating that pyrolysis promoted the formation of micropore structures at 650 °C. Two-dimensional correlation spectroscopy (2D-COS) was employed to explore the temperature-sensitivity of the surface functional groups of the PFRPs. Based on comparison of the volumetric energy density, hydrophobicity, particle density, and strength, the PFRPs prepared at 250–300 °C afforded the best overall performance, where the sample prepared at 300 °C exhibited the maximum hydrophobicity.
A kinetic study based on pinewood (Pinus montezumae) was carried out at heating rates of 5, 10, 15, and 20 °C min−1. The Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS), and Friedman methods were used to analyze the thermal behavior of samples. Thermogravimetry (TG) and derivative thermogravimetry (DTG) curves were obtained at non-isothermal conditions. Ultimate and proximate analyzes from pinewood were obtained and the greater decomposition was in the range of 250 to 380 °C. Mean values of activation energy (Ea) and frequency factor (A) by FWO method were 192.4 kJ mol−1 and 2.73 × 1014 min−1, respectively, whereas the aforementioned values by KAS method were 181.8 kJ mol−1 and 3.32 × 1013 min−1. Lower value of mean activation energy (174.1 kJ mol−1) was obtained with Friedman method.
Torrefaction process is related to pyrolysis treatment in an inert atmosphere which is employed to improve the chemical and physical properties of biomass/solid fuels for energy generation. In present study, mustard crop residue (MCR) which is an abundantly available lignocellulosic waste was torrefied at three different temperatures (200°C, 250°C, and 300°C) for three different residence time (30, 45, and 60 min). Mass yield, energy yield, high heating value, elemental composition, ash content, and volatile matter content of raw and torrefied MCR are computed. The functional behavior and combustion characteristics of raw and torrefied MCR was studied by Fourier Transform Infra-Red Spectrometry (FTIR). The mass and energy yield of torrefied MCR were found to decrease with an increase in torrefaction temperature and residence time. Elemental analysis of torrefied MCR showed an increase in weight percentage of carbon with increase in temperature and residence time of torrefaction due to release of oxygen congaing volatiles. The high heating value was found to upgrade from 16.92 MJ kg�1for raw MCR to21.93 MJ kg�1of torrefied MCR at higher torrefaction temperature and time. FTIR analysis confirmed that hydroxyl group content decreased due to release of H2O, CO, and CO2. Therefore, torrefaction is found to be an effective treatment process for improving physicochemical properties of MCR
This paper presents the kinetics and mechanisms of pyrolysis and gasification processes of sewage sludge and phytomass blends as well as their application in gas conversion. Sewage sludge is a type of combustible waste substance that constitutes a renewable energy source. Mixing sewage sludge with another type of waste biomass can have a beneficial effect on the quality of the fuel produced and may improve the conversion efficiency. Pyrolysis and gasification processes are considered sustainable methods for the production of combustible gas. The two-stage gasification process combining co-pyrolysis and the gasification of “hot” char were studied using a thermogravimetric analyser and a fixed-bed reactor coupled with gas chromatography. The pyrolysis of sewage sludge and Salix viminalis as well as their mixture was performed below the temperature of 900 °C at low heating rates under a nitrogen atmosphere and in non-isothermal conditions. The char gasification experiments were carried out at temperatures of 700, 800 and 900 °C in an atmosphere of air. The effect of the percentage share of Salix viminalis in the tested blends on the pyrolysis process and on the reactivity of “hot” char in the gasification process were investigated. For the tested blends, the kinetic parameters of co-pyrolysis and gasification were determined.
The combustion behavior of bamboo char (BC) under pyrolysis temperatures (673-1173 K) is studied by non-isothermal thermogravimetric analysis. Results show pyrolysis temperature lowers the ignition and burnout performance of biochar. The combustion reactivity firstly increases and then decreases, and BC-973 is the best. Kinetic models of Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose calculate the activation energy (E), integral master-plots method determines reaction mechanism is the reaction order mechanism that when the heating rate is less than 12 K/min, reaction orders firstly decrease and then increase with pyrolysis temperature, and reaction orders are around 1 for 24 K/min. Thermodynamic parameters (ΔH, ΔS and ΔG) are calculated, and the prediction equations about E, ΔH, ΔS and ΔG are proposed. Meanwhile, activation energy under empirical and experimental mechanism are compared, results show that average E values under empirical mechanism are greater in 773-973 K, and the rest of pyrolysis temperatures are adverse.
Phosphonate esters may be used as flame retardants for flammable polymers, but always face low flame-retardant efficiency and melt dripping. Until now, no remarkable progress was made in solving the above two defects, thus tremendously affecting their applications as flame retardants. In current work, from the chemistry viewpoint, we designed and synthesized poly(2-butyne-1,4-diol phenylphosphonate (PPBP) containing alkynyl group to break through above-mentioned defects. Compared with the corresponding control sample poly(1,4-butanediol phenylphosphonate) (PPBOP) without alkynyl, thermal analysis revealed that residua char of the PPBP with C≡C bonds increased to 45.0%, much higher than 1.6% for the PPBOP without C≡C bonds, and greatly increased by 27 folds. Various measurements and kinetic analysis were used to investigate the underlying cause for the leap in charring. It turns out that PPBP was involved in a unique decomposing and crosslinking process upon heating, which played a vital role in the leap in charring for PPBP. The leap in charring might afford polymers better flame retardancy through condensed phase. After incorporation of the PPBP into thermoplastic polyurethane (TPU), burning tests illustrated that PPBP not only endowed TPU with excellent flame retardancy and anti-melt dripping performance, but also resulted in extremely low heat release rate and smoke production rate, correspondingly decreased by 70.7% and 53.9% compared with those of TPU. Various measurements further confirmed that the charring caused by PPBP itself and the enhanced charring of TPU induced by PPBP played a crucial role in the remarkable superior flame retardancy of TPU/PPBP.
Pyrolysis is a promising technology that can efficiently convert biomass into gas, liquid, and solid fuels. Elucidating the biomass pyrolysis reaction mechanism is essential for the effective biomass utilization. However, the biomass components and structure are very complex, which complicates the investigation of biomass pyrolysis using traditional approaches. Two-dimensional perturbation correlation infrared spectroscopy (2D–PCIS) represents a new analytical method for visualizing the raw Fourier transform infrared spectroscopy data. By studying volatile compound release properties, the biomass pyrolysis mechanism can be determined. In this paper, the theoretical concept, developments, and applications of 2D–PCIS are described in detail with the emphasis on probing biomass pyrolysis reactions via the analysis of the functional group evolution and bond breakage processes.
The pyrolysis yields of rapeseed were investigated applying thermogravimetric analysis technique. The pyrolysis experiments were performed up to 1273K at heating rates of 5, 10, 20, 30, 40 and 50K/min in a dynamic nitrogen flow of 40cc/min. Effects of heating rate on the mass losses from the rapeseed were examined using the derivative thermogravimetric analysis profiles. This study showed that important differences on the pyrolytic behavior of rapeseed are observed when heating rate is changed. At the lower heating rates, the maximum rates of mass losses were relatively low. When the heating rate was increased, maximum rates of mass losses also increased. These variations were interpreted by the heterogeneous structure of biomass. Heating rates also concluded to affect the shape of the peaks. Increase in the heating rate shifted the main peak on the DTG profile to the lower temperatures. At low heating rates, there is probably resistance to mass or heat transfer inside the biomass particles. However, increase in heating rate overcame these restrictions, and led to higher conversion rates. The final pyrolysis temperatures were also affected from the variation of the heating rate. Activation energy values were first increased and then decreased depending on the heating rates.
The purpose of this paper is to provide an introduction to the physical processes involved in the combustion of wood and other
cellulosic fuels. This introduction is aimed towards the utilization of the cellulosic fuels as an energy source. A discussion
of a design of the stove is also provided to aid the development of such a device.
This review presents the summary of new studies on pyrolysis of biomass to produce fuels and chemical feedstocks. A number of biomass species, varying from woody and herbaceous biomass to municipal solid waste, food processing residues and industrial wastes, were subjected to different pyrolysis conditions to obtain liquid, gas and solid products. The results of various biomass pyrolysis investigations connected with the chemical composition and some properties of the pyrolysis products as a result of the applied pyrolysis conditions were combined. The characteristics of the liquid products from pyrolysis were examined, and some methods, such as catalytic upgrading or steam reforming, were considered to improve the physical and chemical properties of the liquids to convert them to economic and environmentally acceptable liquid fuels or chemical feedstocks. Outcomes from the kinetic studies performed by applying thermogravimetric analysis were also presented.
Rice husks were pyrolysed in a thermogravimetric analyser in a nitrogen atmosphere to determine the role of temperature and heating rate on their devolatilization. Heating rates of 5–80 °C min−1 up to a final temperature of 720 °C were used. The thermograms showed two main areas of weight loss and the increase in heating rate caused a lateral shift in the thermograms. The pre-exponential factor and activation energies were calculated for each heating rate. The major components of the rice husks — hemicellulose, lignin and two forms of cellulose — were also analysed by thermogravimetric analysis at the different heating rates and compared with the rice husks. The thermograms from the component parts of the rice husks could be directly correlated with the rice husk devolatilization. Rice husks were also pyrolysed in a static batch reactor at identical conditions to the thermogravimetric analyser to determine the composition of the evolving products during devolatilization. The major volatiles evolved during lower temperature pyrolysis were CO, CO2 and H2O and at higher temperatures lower concentrations of CO, CO2, H2O, H2, CH4. C2H6 and oil were evolved.
Biomass is available as a potential resource for energy generation and chemicals. The future supply of biomass energy depends on energy prices and technical progress, both of which are driven by energy policy priorities. Pyrolysis and hydrolysis processes are thought to have great promise as a means for converting biomass into chemicals and higher value fuels. Total amounts of C-12, C-18, and C-24 hydrocarbons obtained from hazelnut shell, beech wood, spruce wood, tea waste, and filter paper were 37.2, 38.2, 37.6, 39.5, and 41.1%, respectively. The straight-chain alkanes from pyrolysis range from C-14 to C-32, and the distribution of straight-chain alkanes exhibit a maximum in the range of C-17 to C-30 in the liquid products of the biomass samples.
Oil seed plants are important biomass energy sources. The rapeseed plant, which yields a high amount of vegetable oil, has a major position among other oil seed plants. In this study the straw stalk of the rapeseed plant (type 00 Brassica napus L.) has been investigated as a candidate for a biomass energy source.
The pyrolytic properties of biomass are controlled by the chemical composition of its major components, namely cellulose, hemicelluloses and lignin and their minor components including extractives and inorganic materials. Pyrolysis of these materials proceeds through a series of complex, concurrent and consecutive reactions and provides a variety of products.Pyrolysis cellulose at lower temperatures below 300° C involves reduction in molecular weight, evolution of water, carbon dioxide and carbon monoxide and formation of char. On heating at higher temperature 300–500° C, the molecule is rapidly depolymerized to anhydroglucose units that further reacts to provide a XXXX pyrolyXXXXA: still higher temperatures, the anhydrosugar compounds undergo fussion, dehydration disproportionation and decarboxylation reaction to provide a mixture of low molecular weight gaseous and volatile produces. The composition of these produces and mechanism and kinetics of their production are reported.
Recent advances in experimental methods and computer modeling have shed new light on the kinetics of cellulose pyrolysis. The rich slate of reaction products that evolve when cellulose is heated implies that the pyrolysis chemistry is exceedingly complex. Nevertheless, a simple, first order, high activation energy (ca. 238 kJ/mol) model accurately describes the pyrolytic decomposition of an extraordinary variety of cellulosic substrates. Secondary vapor-solid interactions are the main source of char formed during cellulose pyrolysis. When a whole biomass substrate is pretreated to remove mineral matter, the pyrolysis kinetics of its cellulose component are very similar to those of pure cellulose. Future work should focus on the effects of mineral matter on pyrolysis, and the secondary vapor-solid reactions which govern char formation.
A simple equation based on proximate analysis (volatile matter and fixed carbon contents) is presented which allows calculation of the higher heating value of lignocellulosics as well as the charcoals resulting from their carbonization. The equation has been tested with different lignocellulosic wastes and chars obtained from carbonization at different temperatures. Deviations from the experimental heating values fall in most cases below 2%. A comparison is presented with some other equations from the literature based on proximate, ultimate and chemical analysis data. As a general conclusion the equation proposed in this paper leads to comparable and in many cases more accurate predictions of heating values and has the advantage of being applicable to a wide range of carbonaceous materials, requiring only a simple, rapid and cheap proximate analysis of the samples.
Theoretical analyses of the burning of wood require realistic models of the main processes occurring, and reliable data for insertion into the equations derived from these models. In the paper, the influence of the physical structure of wood, and the changes therein caused by pyrolysis, on the kinetics and heat of reaction of wood pyrolysis and the thermal conductivity and internal heat transfer mechanisms are discussed. A simple linear pyrolysis models based on zero-order kinetics is used to establish relationships between the rate of advance of the pyrolysis wave and the wood-surface temperature, for different sets of assumptions about the nature of the processes occurring during wood pyrolysis. Quantitative estimates of the effect of altering these assumptions are made using typical values of wood's physical and chemical properties; the effects of varying the kinetics constants and heat of reaction overlikely ranges of values are also studied.A surface-heat balance, giving a relationship between applied heat flux and surface temperature, is used to derive a relationship between applied heat flux and rate of volatile emission from heated wood. This latter relationship compares reasonably well with some experimental data.
Pine needles are available in large quantities in the hilly region of Himalayas in India. Pine needles have good energy potential for exploitation through pyrolysis and gasification. This paper deals with the thermal degradation characteristics of pine needles and its kinetics. Thermal degradation analysis has been done by using a thermogravimetric analyzer from room temperature to 900 °C in air atmosphere at different heating rates, viz. 5, 10, 15, 25 and 30 K min−1. The TGA, DTG and DTA curves exhibited four distinct degradation zones. However, at the low heating rate of 5 K min−1, only three degradation zones were found. The second, third and fourth zones had higher values of activation energy than the first zone. The kinetic parameters were determined by using several methods proposed in the literature assuming single step, irreversible reaction for a particular zone. Agrawal and Sivasubramanian [AIChE J. 33 (1987) 6] method was found to be most consistent. For the total degradation zone the orders of reaction were found in the range of 0.00–2.50 by using Agrawal and Sivasubramanian [AIChE J. 33 (1987) 6] approximation, the activation energy in the range of 34.60–85.34 kJ mol−1 and the preexponential factor in the range of 3.29×104 to 5.98×106 mg1−n min−1. The relative simplicity of the model gives it the potential for applications in the design of large scale biomass-pyrolysis facility in remote areas.
Effect of pyrolysis conditions, such as temperature and substrate composition, i.e. inorganics, on the formation of polycyclic aromatic hydrocarbons (PAHs) from polyphenolic compounds, chlorogenic acid (CA) and lignin, was studied under inert atmosphere. Two routes for the PAH formation were investigated: primary volatile tar and the solid residue, i.e. char. The reactor consisted of a quartz tube with two zones. Zone 1 was used to first pyrolyze the substrate at 250–400 °C to produce a low temperature tar (LTT) and then to pyrolyze the char at 625 °C to produce a high temperature tar (HTT), The LTT and HTT were then passed through zone 2 maintained at temperatures between 700 and 920 °C. Yields of most PAHs increased with temperature, except in a few cases where the yields of two- and three-ring PAHs exhibited a maximum at 870 °C. The maximum may be due to the growth of these PAHs into heavier PAHs. The partial removal of sodium and potassium from lignin decreased the formation of char and PAHs, co-pyrolysis of CA and lignin also altered the PAH distribution. Preliminary analysis of the data from CA gave high activation energies for the PAH formation, with activation energy generally increasing with the PAH size.
This paper investigates the kinetic of pyrolysis and combustion of scrap tyre using thermogravimetric and derivative thermogravimetric analysis method. Three materials, namely tyre rubber powder, tyre fiber and wood powder were studied and compared with each other. The process parameters show that these three materials exhibit different thermal degradation patterns during pyrolysis and combustion process. Thermal degradation models were proposed to derive the kinetic parameters. It was found that the process and kinetic parameters vary with heating rates but are less dependent on the powder sizes. The simulations by the proposed models agreed well with experimental data.
The large variety in municipal solid waste (MSW) composition and differences in thermal degradation behaviour of MSW components makes modelling, design and operation of thermal conversion systems a challenge. The pyrolysis characteristics of 11 different components, representing the dry cellulosic fraction and plastics of MSW, have been investigated. The aim of this study is to obtain detailed information on the pyrolysis characteristics and chemical kinetics of the most important components in MSW. A thermogravimetric analysis including determination of kinetic parameters are performed at a constant heating rate of 10°C/min in an inert atmosphere. The cellulosic fraction of MSW was modelled by three independent parallel reactions describing the degradation of hemicellulose, cellulose and lignin. The plastics polystyrene, polypropylene, low-density polyethylene and high-density polyethylene were all modelled as single reactions describing the degradation of hydrocarbon polymers. The degradation of PVC was modelled with three parallel reactions describing the release of benzene during dehydrochlorination, dehydrochlorination reaction and degradation of remaining hydrocarbons. Possible interactions between different paper and plastic components in mixtures were also investigated. It was found that the reactivity of cellulosic matter was increased in a mixture with PVC.
The pyrolysis of tobacco under a variety of conditions was performed to examine the generation profiles of 29 known toxic compounds in tobacco smoke (hydrogen cyanide, benzo[a]pyrene, aldehydes, volatile organic compounds, phenolics, aromatic amines, etc.). The generation profiles of smoke compounds varied according to three conditions: the pyrolysis temperature (300-1000 degrees C), the pyrolysis atmosphere (in nitrogen and air) and pH of the tobacco leaf (2.89-7.07). Most of the smoke compounds (28 compounds) were generated primarily at temperatures less than 800 degrees C. More than half of the smoke compounds (17 compounds) were unaffected by the type of atmosphere, and seven compounds were significantly affected by pH. These results can provide basic and useful information to further study on the formation mechanisms and the technology involved in the control of smoke generation.
Rapeseed - mustard research in India: 21st century strategies
- P R Kumar