Activation Energy Of Pyrolysis Research Articles

Pyrolysis of combustible fractions in excavated waste: Effect of landfill time on pyrolysis characteristics analyzed by TG-FTIR-MS

Excavated waste in landfills contains non-negligible amounts of combustible fractions, whose mining and thermochemical treatment are promising to save land occupation and achieve energy utilization. Considering the possible changes of combustible fractions in the excavated waste during landfill time, this study comprehensively analyzed the impact of landfill time on the thermogravity characteristics, pyrolysis kinetics, products composition, and pyrolysis pathways of excavated waste using TG-FTIR-MS. The findings indicated a positive correlation between landfill time and the remaining mass resulting from pyrolysis. The activation energies for pyrolysis of excavated waste were found to be greater than those of fresh waste. Specifically, the activation energy values increased from 230.49 kJ/mol to 289.11 kJ/mol for polyethylene, from 216.38 kJ/mol to 260.91 kJ/mol for polypropylene, from 219.04 kJ/mol to 240.06 kJ/mol for expanded polystyrene, and from 210.01 kJ/mol to 279.93 kJ/mol for polyethylene terephthalate, respectively. The increment of activation energies indicates an elevated level of difficulty in the pyrolysis reaction. The pyrolysis kinetics of excavated waste were examined by the Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), and Starink methods. It was found that FWO method showed an optimal fitting result (R2 =0.9681–0.9819), while KAS and Starink methods also showed satisfactory fitting performance. The TG-FTIR-MS results revealed that the effect of landfill time on products categories are negligible, but the change in the content of pyrolysis products is more pronounced. This study is hoped to provide fundamental insights into the thermochemical disposal and energy recovery of excavated waste in landfills.

Pyrolysis interaction of cellulose, hemicellulose and lignin studied by TG-DSC-MS

The pyrolysis kinetics, heat endothermic and exothermic characteristics and gases formation of cellulose, hemicellulose, lignin and their mixtures were investigated by TG-DSC-MS to understand the interaction of biomass three components and its influence on the pyrolysis gas products. It was found that there were complex interactions among three components, and the activation energy of mixtures pyrolysis was mainly divided into two stages. During the pyrolysis process, cellulose could promote the decomposition of lignin and hemicellulose, while hemicelluloses might restrain the decomposition of cellulose and lignin. Furthermore, lignin promoted the decomposition of hemicelluloses but inhibited the decomposition of cellulose. The interactions also had a great influence on the gas products. The gas products generated during pyrolysis of three components were mainly H2, CO, H2O and CO2. Hemicellulose and lignin promote H2 release, while cellulose and lignin inhibit the release of H2O and CO2, and all three components restrain the release of CO. The effect of hemicellulose on H2O and CO2 would depend on pyrolysis temperature of 325 °C.

ReaxFF based molecular dynamics simulation of ethyl butyrate in pyrolysis and combustion

As an alternative to fossil fuels, ethyl butyrate shows excellent combustion characteristics, however, its chemical transformation paths are not clear, which limits development of the chemical kinetic model. In order to reveal the reaction mechanism and influencing factors, the pyrolysis and combustion processes with different densities are simulated through the Reactive Force Field Molecular Dynamics (ReaxFF MD) method. The results show that the chemical reaction rate is correlated positively with system density and temperature. In pyrolysis process, ethyl butyrate first decomposes into ethylene and the corresponding acid, then these groups decompose into the smaller hydrocarbon compounds and oxygen-containing functional groups, eventually evolve into H2O and hydrocarbon molecules. In combustion process, the dissociation products of C-C bond are oxidized to CO2, and the hydrogen atoms are captured by ·OH (or combines with ·H), and H2O generated. The activation energies of pyrolysis and combustion processes are 180.61 kJ/mol and 83.89 kJ/mol, respectively.

Petroleum-like fuels with substantially enriched branched iso-paraffins and benzenes via boehmite-assisted pyrolysis of oil shale

Oil shale (OS) is a potential alternative to substitute/supplement traditional fossil fuels, where catalyst-assisted OS pyrolysis has become a subject of general concern. While great progresses have been realized in this field, the pursuit of high-performance catalysts for a niche OS utilization still remains a formidable challenge, because most of the catalysts face various problems, including, high cost, unsatisfactory performances, etc. Based on a two-stage flash pyrolysis, we herein report our efforts about this issue by using boehmite, a low-cost industrially relevant material of an easy availability, as catalyst. We show that boehmite could arouse 17.0 % decreases in activation energy of OS pyrolysis. When the pyrolysis is executed at the 1st stage (450 °C), the content of hydrocarbons and short-chain aliphatic hydrocarbons (≤C13), which are desired for petroleum-like fuels (PLFs), increases evidently by 56.73 % and 158.5 %, respectively, while that of heteroatomic compounds and long-chain aliphatic hydrocarbons (≥C20), which are undesired for PLFs, decreases distinctly by 60.09 % and 41.6 %, respectively, indicating an evident improvement in the quality of the pyrolysates. Fascinatingly, the content of branched iso-paraffins, especially, monomethyl-, dimethyl- and trimethyl-branched paraffins, which are either efficient octane number boosters, important tectons for functional surfactants, or significant component for high-quality fuels of excellent low-temperature performances, increases substantially by ca. 180.2 % from ca. 16.02 % to 44.89 %. For the 2nd stage at 585 °C, besides a distinctly improved quality of the pyrolysates, the content of benzene, toluene, xylene and trimethylbenzene, which are value-added chemicals broadly employed in numerous industrial fields of paramount importance, is enriched distinctly by 94 %, 65.2 %, 13 %, and 19 %, respectively. We find that the concentration of the Brönsted acid sites (BASs) of the employed boehmite, which contain 94 % medium and strong BASs, is substantially lower than that of Lewis acid sites (LASs), which contain merely 54.91 % medium and strong LASs, such that the competitive-collaborative actions of BASs and LASs confer boehmite with outstanding catalytic reactivity.

Synergistic flame retardancy of piperazine pyrophosphate/magnesium hydroxide/fly ash cenospheres-doped rigid polyurethane foams

In order to explore rigid polyurethane foams (RPUFs) with excellent flame retardancy and mechanical properties, this study incorporates the ternary flame-retardant system of piperazine pyrophosphate (PAPP)/magnesium hydroxide (MH)/fly ash cenospheres (FAC) into RPUFs. The results show that doping 6 wt% FAC significantly improves the flame retardancy of the PAPP/MH/FAC-doped RPUFs. The peak heat release rate (p-HRR) decreases from 236.7 kW·m−2 to 127.2 kW·m−2, while the fire resistance index (FRI) increases from 1.00 to 5.34, and passes a vertical burning (UL-94) test V-0 rating. Meanwhile, the RPUFs possess an intact, compact, and robust non-flammable shielding layer due to the formation of the interpenetrating network structure and the physical accumulation of silicon carbon phosphorus residues. Moreover, the pyrolysis kinetics is modeled using the G(α) with reaction order n = 2, PAPP/MH/FAC-doped RPUFs make the pyrolysis activation energy Eα climb from 78.97 to 131.79 kJ·mol−1 at 237–340 °C, corresponding to the decomposition of PAPP and the excellent thermal stability of FAC. Furthermore, PAPP/MH/FAC-doped RPUFs enhance compressive strength while improving flame retardancy and exhibit excellent formaldehyde adsorption performance (adsorption capacity is 64 %). Therefore, this study explores a novel PAPP/MH/FAC-doped RPUFs, promoting the recycling of industrial coal-fired waste and the development of high-performance building materials.

Insights into the nitrogen-rich pyrolysis of cellulose in the presence of alkali and alkaline earth metals: Structural transformation of target products

Here, cellulose loaded with Ca and K was subjected to nitrogen-rich pyrolysis to investigate how alkali and alkaline earth metals affected its properties and the structural transformation of target products, especially the nitrogen transformation mechanism. Ca significantly reduced the activation energy of nitrogen-rich pyrolysis. The effect of Ca on the component distribution of bio-oil was significantly stronger than that of K. At Ca-0.5, the bio-oil had the highest content of nitrogen-containing compounds (77.98%), and the content of nitrogenous heterocyclic compounds (37.98%) was significantly higher than that of Ca-K-0 (27.75%). Ca and K promoted the production of pyridines. K acted on pyrroles and pyrazoles, while Ca acted on pyrazines. As Ca and K increased, both nitrogen-containing functional groups and nitrogen were enriched in biochar. Ca enhanced the H/C value of biochar and accelerated the conversion of char-N to tar-N. K tended to produce nitrogen-rich biochar with higher graphitization degree and stability.

Pyrolytic kinetics, reaction models and gas evolution of wood material with kerosene by TG-FTIR

The pyrolysis process of typical oils (kerosene, gasoline, etc) penetrating solid combustibles is one of the key behaviors of arsons and fire accidents caused by the leaking and spilling of these flammable oils on solid combustibles. Previous researches have mainly focused on the combustion characteristics of combustible solids infiltrated with flammable oils. However, there is a lack of comprehensive and systematic research on their pyrolysis characteristics, kinetics, and gaseous products. This study explored the pyrolytic behaviors, kinetics, reaction models and pyrolytic gases of pine wood with different contents (0, 5, 10, 20 and 30 wt%) of kerosene via thermogravimetry-Fourier transform infrared analysis (TG-FTIR). The results exhibit that the thermal decomposition processes of the pure pine wood and pine wood-kerosene mixture both show a three-stage process. The average activation energy of the mixture pyrolysis gradually decreases from 181.87 to 129.87 kJ/mol with the increase of kerosene content. The results further identify that the kinetic process of mixtures pyrolysis in the region 2 followed the three-dimensional diffusion model: g(α)= [1 − (1 − α)1/3]2. The principal finding of this study is that the obtained kinetic parameters of mixtures pyrolysis can precisely reproduce and predict conversion degree curves. Moreover, during the pyrolysis of the mixtures, the primary gaseous products identified include H2O, hydrocarbon, CO2, CO, carbonyl compounds, phenols, hydroxyl compounds. As the kerosene content increases, there is a significant rise in the production of hydrocarbons observed at the initial peak (around 420 K). Additionally, the predominant gaseous product observed at the peak temperature is carbonyl compounds. It is expected that this study can provide a practical guideline for the prediction of the fire size, the prevention and control of arson accidents and accident investigation.

Thermal Behavior and Pyrolysis Kinetics of Mushroom Residue with the Introduction of Waste Plastics.

Co-pyrolysis is considered a very promising technology for the treatment of solid wastes as it can rapidly realize the volume reduction of raw materials and obtain high value-added products. To realize the resource utilization of newly emerging solid wastes in relation to edible fungi residue and waste plastics, mushroom residue (MR), a representative of edible fungi residue, was co-pyrolyzed with waste plastic bags (PE), waste plastic lunch boxes (PP), and waste plastic bottles (PET). The thermal behavior and pyrolysis kinetics of the mixtures were investigated. It was found that the softening of the plastics in the mixtures led to an increase in the initial pyrolysis temperature of MR by 2-27 °C, while the pyrolytic intermediates of MR could greatly promote the decomposition of the plastics, resulting in a decrease in the initial pyrolysis temperatures of PE, PP, and PET in the mixtures by 25, 8, and 16 °C, respectively. The mixture of MR and PE (MR/PE) under different mixture ratios showed good synergies, causing the pyrolysis peaks attributed to MR and PE to both move towards the lower temperature region relative to those of individual samples. The increase in heating rate led to enhanced thermal hysteresis of the reaction between MR and PE. The strength of the interaction between plastics and MR based on mass variation was subject to the order PE > PP > PET. The pyrolysis activation energies of MR, PE, PP, and PET calculated from kinetic analysis were 6.18, 119.05, 84.30, and 74.38 kJ/mol, respectively. The activation energies assigned to MR and plastics were both reduced as plastics were introduced to co-pyrolyze with MR, indicating that MR and plastics have a good interaction in the co-pyrolysis process. This study provides theoretical and experimental guidance for the resource utilization of agricultural solid wastes via thermochemical conversion.

Pyrolysis Characteristics and Determination of Kinetic and Thermodynamic Parameters of Raw and Torrefied Chinese Fir.

Torrefaction influences the structural and physicochemical properties of biomass, thus further altering its thermal degradation behavior. In this study, the pyrolysis characteristics, reaction kinetics, and thermodynamic parameters of raw and torrefied Chinese fir (CF) were investigated. The torrefaction was conducted at 220 °C (mild) and 280 °C (severe), the pyrolysis was performed from ambient temperature to 600 °C, and four different heating rates (i.e., 5, 15, 25, and 35 °C/min) were adopted. The activation energy for pyrolysis was estimated by adopting three isoconversional methods. The master-plot method was employed to analyze the reaction mechanism. Furthermore, thermodynamic parameters, i.e., the enthalpy change (ΔH), Gibbs free energy change (ΔG), and entropy change (ΔS), were calculated. The average activation energy increased with the torrefaction temperature, whose values estimated by using different methods ranged from 88.57 to 97.70, from 121.04 to 126.35, and from 167.51 to 179.74 kJ/mol for raw, mildly, and severely torrefied CF samples, respectively. A compensation effect between the activation energy and pre-exponential factor was observed for all samples. The degradation process was characterized as endothermic, involving the formation of activated complexes and requiring extra energy for torrefied samples.

In-situ catalytic pyrolysis of pine powder by ZnCl2 to bio-oil under mild conditions and application of biochar

Fast pyrolysis of biomass is an effective way for biomass conversion and utilization. However, the pyrolysis temperature is usually high because it is a non-catalytic process, resulting in the complicated composition of bio-oil and difficulty to control. Aiming to explore in-situ catalysis in this paper, the fast pyrolysis of lignin, cellulose, corncob and pine wood powder was studied using ZnCl2 as the catalyst. The activation energies of non-catalytic pyrolysis and catalytic pyrolysis were obtained based on kinetic fitting of their thermal gravimetric curves. The variation in pyrolysis oil composition was analyzed. It was found that ZnCl2in situ catalysis could not only significantly reduce the pyrolysis temperature, but also simplify the resultant bio-oil composition. Even under pyrolysis temperature as low as 350 °C, fast pyrolysis of pine wood powder could achieve a yield of 47% of bio-oil, which was predominantly composed of the derivatives of cellulose and hemicellulose. ZnCl2in situ catalysis could significantly decrease the activation energy of cellulose cracking from 304.78 to 112.46 kJ/mol, but has little effect on that of lignin. The carbon residue from ZnCl2-catalyzed pyrolysis was further carbonized at 600 °C, affording activated carbon with adsorption capacity of phenol up to 165 mg/g. The research work provides guidance and reference for the development of in-situ catalytic pyrolysis technology with high efficiency.

Investigation on oxidative pyrolysis characteristics of bituminous coal through thermal analysis and density functional theory

At present, coal is still the main source of energy supply in China. However, However, coal dust, due to spontaneous combustion or gas explosion, seriously affects underground safety production and also threatens the occupational health of underground workers. To understand the causes of harm caused by coal from the perspective of its oxidative pyrolysis characteristics, bituminous coal was selected as the experimental coal sample, To further understand the oxidation pyrolysis characteristics of bituminous coal, thermal analysis and density functional theory were applied. By using industrial analysis, particle size analyzer, SEM and FTIR to characterize the experimental bituminous coal. The multi heating rate experiment of bituminous coal was carried out with thermogravimetric analyzer, and the kinetic analysis results displayed the apparent activation energy of oxidation pyrolysis of bituminous coal ranges from 118.57 to 124.96 kJ mol−1. The TG-FTIR experiments found the main gaseous products of the oxidation pyrolysis of bituminous coal were CO and CO2. The surface electrostatic potential and bond dissociation energy of bituminous coal structure were analyzed by density functional theory. The research results provide important preliminary references for the safe mining of coal mines and the industrial application of bituminous coal.

Study on the Pyrolysis Kinetic Behaviors of Different Vegetable-Tanned Sheepskin Leathers

The pyrolysis behaviors of leathers tanned with hydrolyzable tannins (Tara and Chestnut extracts), and condensed tannins (Quebracho and Mimosa extract) were studied by Thermogravimetric (TG) analysis in the present work. The TG/derivative thermogravimetry (DTG) results showed that the thermal stability of Tara- and Chestnut-tanned samples is poorer than that of Quebracho- and Mimosa-tanned ones. In order to study pyrolysis kinetics, TG experiments at different heating rates were carried out. Two methods of Flynn-Wall-Ozawa (FWO) and Friedman (FR) were employed to calculate the pyrolysis activation energy (Eα) of the samples. It was found that the average Eα of the vegetable-tanned samples is located at the range of 191.7-206.1 kJ/mol. The thermodynamic parameters (pre-exponential factor, Gibbs free energy, enthalpy, and entropy) of the samples were subsequently calculated based on the average Eα by the FR method. The Gibbs free energies of the Chestnut-, Tara-, Quebracho-, and Mimosa-tanned leathers were 176.9 kJ/mol, 179.8 kJ/mol, 179.3 kJ/mol, and 178.2 kJ/mol, respectively. The difference between the average enthalpies and the Eα is less than 5 kJ/mol, which indicated that the pyrolysis process is conductive to the product formation. The mean entropy (ΔS) of the four vegetable-tanned samples is all positive, which suggested that the pyrolysis of the samples could easily take place. This work might provide theoretical guidance for the optimization of vegetable-tanned leather waste pyrolysis.

Investigation of the thermal behavior of Ca(NO3)2·4H2O and its application for the regeneration of HNO3 and CaO

Nitric acid pressure leaching has great potential in treating limonitic laterite. A new method is designed to improve the downstream process. The resulting calcium nitrate solution is concentrated/crystallized/pyrolyzed to achieve the regeneration of nitric acid and calcium oxide. Calcium nitrate pyrolysis is the core process to realize the new method, but the dynamic analysis of this process is relatively lacking and the pyrolysis mechanism is controversial. In this paper, TG-DSC, TG-MS and XRD were applied to systematically study the thermodynamics and phase evolution of calcium nitrate tetrahydrate. It is found that pyrolysis of calcium nitrate tetrahydrate can be divided into four stages: removing free water and part of crystal water, removing residual crystal water, stable existence of anhydrous calcium nitrate, and its decomposition after melting. Calcium nitrite and nitrogen are absent in the process of calcium nitrate pyrolysis. Three iso-conversion methods, including Flynn-Wall-Ozawa method, Kissinger-Akahira-Sunose method and Starink method, were applied to determine activation energies of calcium nitrate pyrolysis as 224.4 kJ/mol, 221.8 kJ/mol and 222.2 kJ/mol. The kinetic mechanism model of calcium nitrate pyrolysis determined by Melak method is closer to An model, which is the random nucleation and growth reaction. Calcium nitrate pyrolysis process further expands the industrial application of nitric acid pressure leaching.

The enhancement of heterobimetallic MOFs on the pyrolysis and laser ignition of FOX-7

The hydrothermal approach had been used to synthesize two new heterobimetallic Metal Organic Frameworks (MOFs), Ba4Pb4(CH3CO2)8[(CH6CO2)4Pb](CH3CO2)4 (PbBa-MOF) and Ba2Ni(CO2H)6(OH2)4 (NiBa-MOF), their structure and surface topography were then examined with XRD and SEM. By using the TG-DSC and TG-FTIR-MS methods, the pyrolytic decomposition properties of MOFs and their catalytic activities on the 1,1-diamino-2,2-dintroethene (FOX-7) pyrolysis were investigated. The PbBa-MOF has a single thermal decomposition process with a high thermal decomposition temperature, while NiBa-MOF has a three-stage thermal decomposition process initiated from a lower temperature. Furthermore, the thermolysis peak temperature of the FOX-7/PbBa-MOF and FOX-7/NiBa-MOF mixture has a great decrease by 24.2 °C and 27.4 °C compared with the FOX-7. However, the low pyrolysis peak temperature and the pyrolysis activation energy (Ea) are almost unchanged. The selective high temperature catalytic effect of the MOFs on FOX-7 results from the activation of -NH2 in the high temperature pyrolytic decomposition of FOX-7 by the metallic ions of the MOFs. This thermal catalytic property indicates that MOFs can promote the pyrolytic decomposition of FOX-7 while ensuring the safety requirements for the compatibility of energetic mixtures in the preparation of propellants. The relationship between the features of pyrolytic decomposition and laser ignition was finally covered and defined. The two MOFs decreased the minimum ignition energy and ignition delay time of the FOX-7. Novel MOFs combustion catalyst may strengthen ignition and combustion features of the high-energy and low-sensitivity solid propellants containing FOX-7.

Pyrolysis of Colombian spent coffee grounds (SCGs), characterization of bio-oil, and study of its antioxidant properties

ABSTRACT Coffee is the second most consumed beverage in the world. Spent coffee grounds (SCGs) are promising raw material for pyrolysis. The Kissinger-Akahira-Sunose model (KAS) and Ozawa-Flynn Wall (OFW), determined the pyrolysis activation energy to be 142.40 and 66.08 kJ/mol, respectively. The pyrolysis products were bio-oil with a 22.5% yield and a calorific power of 28.91 MJ/kg. The bio-oil composition was 50.86% fatty acids, 31.65% linear hydrocarbons, and 11.31% aromatics, as determined by GC-MS. The total phenolic content (TPC) was 362 ± 44 mg GA g−1, with DPPH activity of 24.8 ± 2% inhibition and antioxidant activity of 108.5 ± 13.6 mg L−1 of Trolox equivalents. The results showed that bio-oil could be used as a biofuel and a source of chemical compounds.

Biofuels from Pyrolysis of Third-Generation Biomass from Household and Garden Waste Composting Bin: Kinetics Analysis

The modern society produces large amounts of household waste with high organic matter content. The vermicomposting of household waste produces high-value humic substances and is a way to stabilize organic material for later use as raw material (3rd generation biomass) for bioenergy proposes. A 6-month matured compost, combining vegetable and fruit scraps from domestic trash and grass and shrub clippings from yard waste, was evaluated to assess its potential as a raw material in pyrolysis processes. The pyrolysis activation energy (Kissinger) of the composted material showed values in the range of 200–300 kJ/mol, thus confirming its suitability for pyrolysis processes with promising H2 yields. The treatment of the composted material with H2SO4 and NaOH solution (boiling; 1 mol/L) led to the production of solid residues that present higher pyrolysis activation energies, reaching 550 kJ/mol for the most resilient fraction, which makes them suitable to produce carbonaceous materials (biochar) that will have incorporated the inorganics existing in the original compost (ashes 37.6%). The high content of inorganics would play a chief role during pyrolysis since they act as gasification promoters.

Research on the influence of sequential isopropanolysis liquefaction on the composition of liquid tars and physicochemical structure evolution of renbei lignite

A green and efficient sequential isopropanolysis liquefaction approach was reported to convert lignite into high yield of liquid tars (LTs) as fuels/value-added chemicals in this research, but its influence on the molecular structure composition of LTs and physicochemical structure evolution of lignite still received little attention. The sequential isopropanolysis of RB lignite was performed at 240, 280, and 320 °C in isopropanol for obtaining three LTs (LT240 °C, LT280 °C, and LT320 °C) and three residues (R240 °C, R280 °C, and R320 °C). Among three LTs, phenols represented the highest relative content value, accounting for 72.54, 90.48, and 84.83%, respectively, and mainly can be divided into phenol and (C1–C8)-phenol. There was hydrocarbon, Oy (y = 1–5), NOy (y = 0–2), N2Oy (y = 0–2), N3Oy (y = 0–1), NxSz (x = 0–1, z = 1–2), and SNxOy (x = 1–2, y = 1–2) class species existed in three LTs on the basic of the analysis with quadrupole exactive orbitrap mass spectrometer (QEOTMS). Notably, O1 and O2 class species were the more abundant components in three LTs. The cleavage of C–O bridged bonds should be the main reaction path and the graphitization degree of residues significantly enhanced. The main pyrolysis zone of residues shifted to higher temperature area and the pyrolysis activation energy of stage II increased.

High-Temperature Pyrolysis of N-Tetracosane Based on ReaxFF Molecular Dynamics Simulation.

In order to further understand the high-temperature reaction process and pyrolysis mechanism of hydrocarbon fuels, the high-temperature pyrolysis behavior of n-tetracosane (C24H50) was investigated in this paper via the reaction force field (ReaxFF) method-based molecular dynamics approach. There are two main types of initial reaction channels for n-heptane pyrolysis, C-C and C-H bond fission. At low temperatures, there is little difference in the percentage of the two reaction channels. With the temperature increase, C-C bond fission dominates, and a small amount of n-tetracosane is decomposed by reaction with intermediates. It is found that H radicals and CH3 radicals are widely present throughout the pyrolysis process, but the amount is little at the end of the pyrolysis. In addition, the distribution of the main products H2, CH4, and C2H4, and related reactions are investigated. The pyrolysis mechanism was constructed based on the generation of major products. The activation energy of C24H50 pyrolysis is 277.19 kJ/mol, obtained by kinetic analysis in the temperature range of 2400-3600 K.

Pyrolysis of post-methanated distillery effluent (PMDE) solid waste: Thermogravimetric degradation, kinetic and thermodynamic study with a circular bioeconomy approach

Post-methanated distillery effluent (PMDE) is a harmful dark brown to black color distillery effluent and is often released in open pond systems after anaerobic digestion by molasses-based distilleries. Due to the high standards imposed by Environmental Protection Acts, various methods of treating effluent were explored. However, pyrolysis showed excellent potential to treat it and recover energy. Hence, the present study explores the viability of producing energy from PMDE solid waste through pyrolysis. The reaction was performed at 900 °C with 20 °C min −1 heating rate in a fixed bed reactor, resulting in 36.12 wt% condensable volatiles, 22.6 wt% non-condensable gases, and 41.28 wt% solid biochar. The gas chromatographic (GC) analysis of the non-condensable gas revealed the presence of CO (17.83 vol%), H2 (8.10 vol%), and CH4 (4.30 vol%) in significant amounts, and C2H4, C2H6, C3H8, and C4H10 in minor quantities. Biochar obtained from the process has a microscopic surface area of 62.13 m2 g−1. A kinetic and thermodynamic study was performed using isoconversional methods to understand the reaction mechanism. Kinetic analysis showed the activation energy of PMDE solid waste pyrolysis to vary from 120 kJ mol −1 to 180 kJ mol −1 as conversion increases, and thermodynamic parameters (ΔH, ΔS, and ΔG) show the explanation for variation in activation energy. Additionally, the bio-circular economic approach of PMDE solid waste was presented.

Catalytic pyrolysis of rice husk over defect-rich beta zeolites for biofuel production

The Coats-Redfern method was used to identify the catalytic and non-catalytic pyrolysis of rice husk biomass kinetics by using thermogravimetric analysis. MTES-beta-zeolite and beta-zeolite were synthesized by dry gel conversion method. Both synthesized zeolites and commercial beta-zeolite were mixed with ground rice husk in a 1:0.03 ratio by mass. Thermal degradation for catalytic and non-catalytic pyrolysis of rice husk biomass occurred at 523 K to 823 K. Conversions were majorly observed in Section I (523–633 K) and Section II (723–823 K) temperature ranges. Order and diffusion-based models were in approximation with each other for both temperature ranges. From the Ea trends, it can be understood that MTES beta-zeolite has no significant effect on pyrolysis in Section I and has promising results in Section II. The beta-zeolite and commercial beta-zeolite gave better results for all reaction models in both sections by lowering the activation energies for catalytic pyrolysis of RH compared to those for non-catalytic pyrolysis. By comparing catalytic with non-catalytic pyrolysis of rice husk, activation energy significantly varied for both sections. Thermodynamic parameters (ΔH) and (ΔG) values indicated the activated complex formation and non-spontaneity of the reaction. The negative value of (ΔS) suggested a more ordered state. Furthermore, pyrolysis of rice husk with commercial beta zeolite was performed and biochar produced with a yield of approximately 75%. Different organic compounds were also obtained in the bio-oil which include different aliphatic compounds.