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Branch wood, as a renewable biomass resource, presents certain challenges due to its high volume, complex physical properties, difficulty in handling, and relatively high production costs. Potassium chloride (KCl) treatments were applied to ash branch wood (ABW) using solutions with concentrations of 5%, 10%, and 15% via immersion. Pyrolysis tests were performed at different pyrolysis temperatures (450 °C, 600 °C, 750 °C) and different pyrolysis times (2 h, 3 h, 4 h). The thermal degradation behavior was meticulously examined through Thermogravimetric Analysis (TGA). Furthermore, the pyrolysis kinetics were assessed using the Flynn–Wall–Ozawa (FWO) model, which allowed for the determination of the kinetic parameters and the exploration of the catalytic influence of KCl on the pyrolysis process. The morphology and adsorption properties of the biochar were evaluated employing SEM-EDS and BET characterization methods, respectively. The results show that the higher the impregnation concentration of ABW, the greater the shift in the TG and DTG curves, and the lower the initial temperature and maximum weight loss temperature in the devolatilization stage. The calculation of pyrolysis kinetic parameters indicates that adding a higher concentration of KCl to ABW results in a lower initial temperature and activation energy for the volatile phase of ABW. At the same time, a higher KCl concentration leads to an increased biochar yield; under single-factor conditions, a biochar yield of up to 35.81% can be achieved with an impregnation concentration of 15%. A lower KCl is more conducive to the pyrolysis reaction, with a lower activation energy throughout the devolatilization stage compared to raw ABW. Additionally, ABW treated with a low concentration of KCl results in a higher specific surface area and pore volume of the biochar. The maximum values are achieved when the KCl solution concentration is 5%, with a specific surface area of 4.2 m2/g and a pore volume of 0.00914 cm3/g. Based on these results, this paper explores the catalytic pyrolysis patterns of KCl on branch waste, providing theoretical guidance for the effective utilization of branch wood and the preparation process of biochar. [ABSTRACT FROM AUTHOR]

The effective utilization of camphor extracted oil residues (CEOR) is an important focus in the development of the camphor essential oil industry's entire chain. In this paper, the pyrolysis characteristics and kinetics of CEOR were investigated by thermogravimetric analysis. Then a fixed-bed pyrolysis reactor was used to pyrolyze the pyrolysis products at different temperatures (400, 500, 600 Tiand 700 °C) to study the influence of temperature on the composition and characteristics of the pyrolysis products. The results showed that with the increasing of heating rate, TG and DTG curves shifted to the high temperature region, the residual mass increased, and the activation energy increased from 37.07 kJ/mol to 41.31 kJ/mol. With the increasing of pyrolysis temperature, the relative contents of solid, liquid, and gas products obtained from CEOR pyrolysis changed greatly. The specific surface area and pore volume of biochar increased, the I(GR+VL+VR)/ID value decreased significantly, and the aromaticity and carbonization degree of carbon structure increased. There were 50 main components detected in the liquid products, mainly phenols, ketones, acids, hydrocarbons, and aldehydes, as well as a small amount of esters, alcohols and other substances. When the pyrolysis temperature was 600 °C, the relative content of phenolic compounds was 48.46 %, and mainly alkoxy phenolic compounds. [ABSTRACT FROM AUTHOR]

Sugarcane bagasse is rich in cellulose and lignin, and the recycling of bagasse has become an important research field with the increasing global concern for sustainable development and environmental protection. In this paper, TG-MS-FTIR equipment was used to analyze the pyrolysis characteristics of bagasse from Guangxi under different heating rates and different atmospheres, which is conducive to the reuse of bagasse from the waste gas produced in the sugar plant. The results showed that the pyrolysis rate of sugarcane bagasse in the air atmosphere was faster than that in the nitrogen atmosphere and showed a double-peak trend, and the Coats–Redfern computational model could more accurately simulate the process of pyrolysis. The lower heating rate could overcome the heat transfer hysteresis phenomenon in the process of pyrolysis. In the air atmosphere, the contact time between oxygen and volatile products was shorter due to the high heating rate, and more and more complex species were precipitated at 10 °C/min than at 20 °C/min. In the nitrogen atmosphere, it was favorable to produce more kinds and quantities of gas products, because it did not react with oxygen. FTIR detected CH4, CO, H2O, CO2, C-O-C, and C=O during pyrolysis in nitrogen, and some of C-O-C and C=O were cracked into small molecule compounds at high temperature. [ABSTRACT FROM AUTHOR]

To assess the fire safety of cables in the service process, the influence of thermal-aging temperature on the combustion properties, pyrolysis properties, and mechanical properties of civilian-type flame-retardant electrical cables was investigated. Flammability test shows that the LOI value of the sheath increases with the rise of thermal-aging temperature, primarily ascribed to the formation of a dense carbon layer. Cone calorimeter test shows that the total heat release (THR) value and residual mass of the cables firstly decrease and then increase as the thermal-aging temperature rises. After 21 days of aging treatment at 120 °C, the THR and peak heat release rate values of the cable are reduced to the lowest values of 88.9 kW m−2 and 109.2 MJ m−2, respectively. TG analysis shows that the onset decomposition temperature of the sheath first increases and then decreases with the rise of the thermal-aging temperature, where the onset decomposition temperature declines sharply after 150 °C thermal aging for 21 days. Mechanical test shows that as thermal-aging temperature increases, the elongation at break of the sheath decreases sharply, while the tensile strength increases significantly. This is mainly because the molecular structure of the aged sheathing material is changed, as supported by SEM and FTIR analyses. [ABSTRACT FROM AUTHOR]

In order to prevent ecological environment pollution and water resource waste effectively, the study of pyrolysis treatment technology is of great significance in guiding the scientific treatment of municipal sludge. Thermogravimetric analysis was used to investigate the TG (thermogravimetric analysis) and DTG (derivative thermogravimetry) curves of five typical municipal sludges in Chongqing under different heating rates. The distribution characteristics of volatile analysis parameters such as characteristic index D, comprehensive combustion characteristic index, activation energy, and pre-exponential factor under pyrolysis and combustion conditions were analyzed, revealing its pyrolysis and combustion characteristics and kinetic laws. The results show that the volatile and ash contents of the five municipal sludges is higher, while the fixed carbon content is lower. As the heating rate increases, the comprehensive pyrolysis and combustion performance of various sludges improve. Based on the pyrolysis and combustion characteristics parameters at all heating rates, the comprehensive pyrolysis performance of Tuzhu and Yudong sludge is the best, while Tangjiaqiao sludge exhibits the best comprehensive combustion performance. Kinetic analysis are used to toinvestigate regular pattern, the results show that the average activation energy of the pyrolysis process for Yudong sludge is lower than the other four types of sludge, at 112. 34 kJ/mol. Similarly, the average activation energy of the combustion process of Tangjiaqiao sludge is lower than the other four types of sludge, at 67. 46 kJ/mol. It is concluded that Yudong and Tangjiaqiao sludge exhibit excellent pyrolysis and combustion characteristics, respectively. [ABSTRACT FROM AUTHOR]

Hazardous paint waste from industrial production is an ever-growing concern due to its toxicity and flammability effect. Currently, pyrolysis is one of the promising technologies for paint waste disposal because of its ability to minimize and disinfect waste together with energy recovery. In this study, characterization of pyrolysis of polyurethane paint slags was conducted using TGA-FTIR-GC/MS, and the evolved products were analyzed. The effect of heating rate (10 °C per minute, 20 °C per minute, and 30 °C per minute) were assessed. The TGA results showed that two stages involved in the pyrolysis of waterborne polyurethane paint slag. The first stage was 200~325 °C, while the second stage involved the intense weight loss at 330~500 °C. In addition, the thermal pyrolysis of oily polyurethane included four stages during the pyrolysis reaction. The first three stages were 200~300 °C, 300~435 °C, and 435~640 °C, respectively, which correspond to the volatiles and the decomposition reaction of some organic matter. The fourth stage was the pyrolysis of fixed carbon at 640~790 °C. The increase of heating rate can improve the pyrolysis intensity of two polyurethane paint slags. The FTIR results showed that a large amount of CH4, CO2, CO, H2O, alkanes, olefins, and aromatic compounds were emitted during the pyrolysis of the two paint slags. The GC/MS results concluded that the pyrolysis products of waterborne paint slag were mainly HC and O-compounds, and the pyrolysis products of oily paint slag also included N-compounds. This study provides a theoretical reference for the pyrolysis characteristics and product properties of polyurethane paint slags. [ABSTRACT FROM AUTHOR]

Foaming agents are widely used in the processing of polymer materials. The p-toluenesulfonyl hydrazide (TSH), as a foaming agent, generates foams that are fine and uniform. However, the extensive heat produced during the thermal decomposition of foaming agents greatly increases the risk throughout the process. Accidents involving TSH have caused severe economic losses of 300,000 RMB in China. In this study, a differential scanning calorimetry, adiabatic accelerating calorimeter, thermogravimetric-infrared spectrometer, and Gaussian molecular simulation software were adopted to explore the pyrolysis characteristics and decomposition mechanism of TSH and TSH containing impurities (water, urea). Experimental results indicated that the apparent activation energy of pure TSH was 173.39 kJ mol−1. The potential for explosion is high when TSH decomposed, as it releases heat and gaseous products. The addition of water or urea reduces the hazard level of TSH, but urea promotes the decomposition of TSH. The time it takes for a reaction to reach its maximum rate under adiabatic conditions (TMRad) to reach 24 h (TD24) and 8 h (TD8) was 46.8 and 56 °C, respectively. Comparing the experimental results with molecular simulations, the products of thermal decomposition of TSH include nitrogen, water, aryl disulphides, and sulphide sulphonates. [ABSTRACT FROM AUTHOR]

Cigar tobacco residues are a special air-cured tobacco material with increasing production in domestic. In this present study, the effect of glycerol addition on the pyrolysis characteristic, kinetic behavior, and release of pyrolytic products was investigated by using thermogravimetry coupled with online FTIR and self-built infrared tubular furnace. The thermal weight loss process of cigar tobacco could be divided into four stages, and the glycerol exhibited significant impact on the pyrolysis process. The stage II corresponding the decomposition of volatile components and hemicellulose shifted to the lower temperature accompanied with an increase of DTGmax and weight loss at this stage. The Ti, Tf, and residues were decreased, while the CPI was increased as for the CT-G sample, indicating an increased reactivity and comprehensive pyrolysis performance. Gauss peak fitting was used to separate the pyrolysis process of different pseudocomponents in the tobacco biomass. Pyrolysis kinetic analysis based on Coats-Redfern method showed that the activation energy for the decomposition of each pseudocomponents decreased after the addition of glycerol. The online FTIR and MS analysis also reflected the interaction between glycerol and biomass through the release of pyrolytic gaseous products. GC–MS was further used to analyze the compositions of pyrolytic products in the trapped particulate matter under different heating rates. High heating rate was beneficial for the sufficient release of pyrolysis products and aroma compounds. The glycerol addition inhibited the generation of alkaloids, phenols, esters, ketones, acids, and heterocyclic compounds, indicating some effect may exist between cigar tobacco and glycerol. [ABSTRACT FROM AUTHOR]

Plastic products are an indispensable part of life and are widely used in different fields. However, plastic products have the characteristics of short average service life and not easy to degrade naturally, which are prone to cause serious environmental pollution by long-term accumulation in the environment. The use of low-cost catalysts is the goal pursued by enterprises. In this paper, polypropylene (PP), low-density polyethylene (LDPE), polystyrene (PS), mixed waste plastics (WPs) and spent FCC catalyst (a solid waste produced by oil refining enterprises) were used as research objects to simulate the pyrolysis and catalytic pyrolysis of waste plastics in real life. The results showed that compared with the direct pyrolysis of plastics, the addition of spent FCC catalysts could significantly reduce the initial pyrolysis temperature of PP, LDPE and WPs, with the largest decrease in the initial pyrolysis temperature of PP (about 59 K). The average activation energy of PP, LDPE and WPs decreased with the participation of spent FCC catalyst compared with the direct pyrolysis. Among them, the activation energy of LDPE decreased most significantly (about 22 mass%), followed by PP, and WPs decreased the least. However, the results of thermogravimetric analysis and kinetic calculations showed that the spent FCC catalyst was not suitable for catalytic pyrolysis of PS. The purpose of this experiment is to promote "circular economy". The solid waste products produced by oil refining enterprises are applied to the catalytic pyrolysis of waste plastics, which provides theoretical support and data reference for reducing the energy consumption of plastic pyrolysis and realizing the diversified application of spent FCC catalysts. [ABSTRACT FROM AUTHOR]

In the present study, the effects of pretreatments with different solvents (hydrochloric acid, sodium hydroxide, and ethanol) on the physicochemical structure and pyrolysis behavior of tobacco stem (TS) were investigated. Elemental compositions analysis showed that acid washing increased the carbon content and exhibited a high removal percentage for the inorganic species. SEM, BET, and FTIR analysis showed that the pretreatments exerted different effect on the surface and microstructure. Furthermore, the pyrolysis characteristics analysis indicated that solvent pretreatment increased the initial pyrolysis temperature due to the removal of unstable volatile components, especially for the acid and alkali washing samples. Meanwhile, hydrochloric acid pretreatment increased the maximum pyrolysis rate temperature of cellulose decomposition stage and decreased the char residues due to the large removal of inorganic species, while alkali treatment produced the opposite result. Pyrolysis kinetic analysis based on Coats-Redfern method showed that F1.5 chemical reaction model can be used to describe the pyrolysis stages of TS samples and a decreased activation energy was observed during the decomposition of cellulose stage for the acid and alkali washed samples. The released gaseous products during the pyrolysis process were also monitored by using TG-FTIR technique, and the gaseous release behavior was different from each other. [ABSTRACT FROM AUTHOR]

Horse manure was pretreated by microwave wet torrefaction, and the effects of reaction solvent and torrefaction temperature on composition, thermal degradation characteristics, higher heating value, energy yield and morphology of horse manure were investigated. The results showed that the fixed carbon content and higher heating value of horse manure increased with the increase of temperature, while the energy yield decreased with the increase of temperature. Compared with the raw horse manure, the fixed carbon content increased significantly, the O/C ratio decreased by 28.00%, the higher heating value increased by 21.07%, and the energy yield obtained was 74.30% for torrefied horse manure obtained in pure water solvent at 200 ℃. Compared with the raw materials, the torrefied horse manure obtained in pure water and succinic acid has more ash content, while the sulfuric acid solvent can reduce the content of metal elements that form ash by 50.00%. Microwave wet torrefaction reduced the pyrolysis reactivity of horse manure but led to the improvement in combustion reactivity. The pore structure of the torrefied horse manure obtained in pure water solvent was more evident. The present work shows that microwave wet torrefaction can improve the quality of horse manure, in which the water is shown to be a more suitable reaction solvent than dilute acid at torrefied temperature of 200 ℃. [ABSTRACT FROM AUTHOR]

Organic fireproof plugging material (OFPM) is commonly applied in buildings to prevent the spread of smoke and flame. Its pyrolysis characteristics, reaction mechanisms and gas emission were studied by thermogravimetric analysis coupled with Fourier infrared spectroscopy and mass spectrometry (TG-FTIR-MS). The thermogravimetric analysis showed that the pyrolysis process of OFPM in nitrogen might be divided into four stages, which could be attributed to the dehydrogenation of polychloroprene (PCP), depolymerization of PCP and decomposition of kaolinite and carbonate. The reaction mechanism of OFPM in nitrogen atmosphere was further investigated by various kinetic methods. The average activation energy of the four stages was 92.47, 166.47, 239.69 and 232.72 kJ mol−1. In addition, (g(a) = [1−(1–a)−3]/ (−3)) was responsible for Stage I, and (g(a) = [−ln(1–a)]2) was responsible for Stage IV. The characteristic parameters and kinetic triplets were verified by predicting the experimental data at an extra heating rate. The predicted conversion rate curve was consistent with the experimental conversion rate curve, which manifested the accuracy of the obtained parameters. In addition, the evolved gas consisted of ethane, HCl, 1, 3-butadiene, 2-chloro-1, 3-butadiene and CO2 by the FTIR-MS analysis. Eventually, the pyrolysis pathway was proposed based upon thermogravimetric and gas analysis results. [ABSTRACT FROM AUTHOR]

Thermogravimetry was used to reveal the pyrolysis differences of tobacco stems in different storage years in Henan, Hunan and Guizhou. The surface structure, pyrolysis characteristics and gaseous product composition of tobacco stems in different storage years in Henan were analyzed by electron microscopy and the IG-FTIR instrument,and the difference of kinetic parameters in each weight loss stage of stem in different years during the pyrolysis were compared and analyzed based on the Coats-Redfern method. The results showed that the effects of different storage years on the thermal weight-loss behavior of tobacco stems from Henan, Hunan and Guizhou were similar. The CPI value of tobacco stems stored for 1 year (1. 27-1. 39x10-4%-min-1--2) was higher than that of tobacco stems stored for 2 and 3 years, indicating good pyrolysis characteristics; the residual rate of tobacco stems stored for 3 years was 18. 18%-27. 45%, with poor thermal stability. While the types of pyrolysis gas products released by tobacco stems in different storage years in Henan were similar, and the maximum gas product release rate was shown as follows: tobacco stems stored for 3 years> those stored for 2 years> those stored for 1 year, and the integrity of the surface structure of tobacco stem was poor after 3 years storage, the main weight loss stages during the thermal decomposition of different storage years tobacco stem was mainly controlled by a 1. 5-order chemical reaction model. [ABSTRACT FROM AUTHOR]

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Although metals (Fe(III)) loaded with BC (MBC) exhibited good catalytic reactivity, the structural evolution process of MBC with pyrolysis and the evaluation of electron transfer capacity of MBC during persulfate oxidation were typically overlooked. Results of this study indicated that increasing pyrolysis temperature could promote the carbonization of biomass and lead to the formation of a well-developed microporous structure. Large numbers of functional groups and Fe species were formed by pyrolysis, but the content varies greatly under different pyrolysis temperatures. MBC prepared at pyrolysis temperature of 300 °C (MBC300) exhibited an excellent activation capacity, and the removal efficiency of 2,4-dinitrotoluene reached 83.7% within 5 h of the reaction by adding in 2.5 mmol/L persulfate and 0.5 g/L MBC300. Sulfate radical (SO4·-) and hydroxyl radical (·OH) participated in the reaction, but ·OH was mainly responsible for the degradation of 2,4-dinitrotoluene. Multiple characterization methods confirmed that Fe(III) maghemite and Fe 2p1/2 in MBCs mainly promoted the activation of persulfate, and oxygen-containing functional groups as an electronic shuttle accelerated the electron transfer in the persulfate/MBC system. Compared to that of biochar, the electron donating and electron accepting capacity of MBC were increased by an order of magnitude. This result is of significance for the preparation of green activation material used in the remediation of organically polluted groundwater with persulfate oxidation. [ABSTRACT FROM AUTHOR]

In order to explore the effects of different wood types with different chemical compositions and structures on the types and amounts of polycyclic aromatic hydrocarbons produced in traditional smoked meat products, the structural and pyrolysis characteristics of lignin in five kinds of wood commonly used in the production of traditional smoked and roasted meat products, pine, poplar, beech, jujube and apple wood, were investigated by infrared spectroscopy, Raman spectroscopy, thermogravimetry and thermogravimetry coupled with infrared spectroscopy. The results showed that there were differences in the contents of lignin, guaiacyl (G) and syringyl (S) in the five kinds of wood. The pyrolysis process involved three stages, mainly in the range of 200?500 ℃, but the mass loss rate, mass loss temperature, pyrolysis rate and pyrolysis temperature of lignin were different among different kinds of wood, indicating that there are significant differences in the thermal stability of lignin from different wood sources. Differences in lignin content, S/G structure content and side chain structure in smoked and roasted wood could lead to different thermal stability, and different pyrolysis characteristics could in turn affect the formation of harmful substances such as polycyclic aromatic hydrocarbons.

The current study aimed to determine the characteristics and kinetic parameters for the pyrolysis of printed circuit board (PCB) wastes including the analysis of evolved gases during the processes at different particle sizes. First, PCB wastes were examined using SEM–EDS, SEM-Mapping and FTIR to gain a better understanding of their structures. Then, non-isothermal TG-FTIR analyses of PCB wastes were conducted from ambient temperature to 800 °C under N2 atmosphere. The thermal decomposition of PCB wastes occurred in four stages. The second stage was determined as the main pyrolysis stage. The average apparent activation energies (Ea) of main pyrolysis stage calculated using the isoconversional methods (Friedman, Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose and Starink) were in the ranges of 205–240, 144–158 and 147–161 kJ mol−1 ranges for the studied particle sizes of PCB-2 (180 μm–1.18 mm), PCB-3 (90–180 μm) and PCB-4 (63–90 μm), respectively, which pointed out an effect of particle size on Ea value conversely to a previously reported literature study. Moreover, Coats-Redfern and Criado methods confirmed each other and revealed the reaction mechanism of main pyrolysis stage as F2-2.5. Based on the evolved gas analyses, the most common emission of PCB wastes was CO2 associated with plastic, brominated compounds, polycarbonate, and epoxy resins decomposition. [ABSTRACT FROM AUTHOR]

In the present study, the effect of hydrochloric acid washing on the structure characteristic and pyrolysis behavior of tobacco stalk were investigated. Proximate analysis and elemental compositions of the samples showed that the volatiles and ash contents decreased while fixed carbon increased after the acid washing pretreatment. Meanwhile, the inorganic species can be greatly removed and HHV of acid-washed tobacco stalk was increased by 20.52% to 17.15 MJ/kg. FTIR and XRD analysis showed that acid washing also changed the surface chemical and cellulose crystalline structure of tobacco stalk. Furthermore, pyrolysis characteristic parameters obtained from thermogravimetry analysis indicated that acid washing increased the initial and final pyrolysis temperature, as well as the comprehensive pyrolysis index of biomass because of the removal of unstable volatile components and the change of microstructure. Pyrolysis kinetic behavior was studied through Coats–Redfern and Kissinger–Akahira–Sunose methods, and the decreased ∆H and negative ∆S for W-TS during the pyrolysis process may indicate an enhanced reaction reactivity after the acid washing. [ABSTRACT FROM AUTHOR]

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sludge pyrolysis is a promising method for treating excess sludge as a by-product of municipal sewage plants, allowing for energy self-sufficiency and resource recovery. Before sludge pyrolysis begins, a few conditioning agents are added to the sludge that promote sludge dewatering. Potassium ferrate (K2FeO4) is applied as a conditioning agent with both cracking and flocculation effects, but the effects of K2FeO4 on the release characteristics of nitrogen, sulfur, and chlorine during sludge pyrolysis have not been elucidated. In this study, we analyzed the sludge pyrolysis characteristics and chemical state changes of N, S, and Cl contaminants in the dewatered sludge after K2FeO4 conditioning before and after pyrolysis. Further, the release characteristics of condensable/noncondensable gases during pyrolysis were assessed using thermogravimetric mass spectrometry (TG-MS) and pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) analyses before and after conditioning. We found that potassium pertechnetate reduced the activation energy required for the sludge in the pyrolysis process. Noticeably this process made the sludge more susceptible to thermal decomposition leading to volatile production and also influenced the release of different contaminants generated by the pyrolysis process. Moreover, K2FeO4 promoted the release of C/H/O gases and reduced the release of N/S/Cl pollutant gases from the sludge. Overall, this study provides a theoretical basis for the selection of conditioning agents for the sludge conditioning and dewatering steps during the sludge pyrolysis process. [ABSTRACT FROM AUTHOR]

Minerals, as a secondary component, have a significant influence on the structure and thermal reactivity of coal. In order to further clarify the effect of minerals on the structure and thermal conversion of Hefeng sub-bituminous coal (HSBC) from Xinjiang, the mineral removal of HSBC was investigated. In this paper, acid-washing treatment was used to remove minerals from HSBC. The ash composition, mineral composition, and chemical structure of HSBC and its acid-washed coals were analyzed by X-ray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Their pyrolysis characteristics and pyrolysis products were examined by thermogravimetric infrared gas chromatography/mass spectrometry (TG-FTIR-GC/MS). Acid-washing pretreatment not only significantly alters the mineral composition of the coal, but also destroys its organic structure, resulting in decreased coal stability. Especially, hydrofluoric acid (HF), as well as hydrochloric acid and hydrofluoric acid (HCl–HF) stepwise acid-washing treatment. In addition, the pretreatment effectively increased the weight loss during coal pyrolysis by destroying the organic structure of the coal and improving the pyrolysis reactivity of coal. The pretreatment inhibits the generation of CO 2 by changing the form of oxygen-containing functional groups in coal, allowing more oxygen-containing functional groups to migrate into coal tar, thereby promoting the formation of phenols, aromatics and alkanes, and improving the quality of coal tar. • The composition structure and pyrolysis behaviors of HSBC is investigated. • Evolution behavior of typical gas products is thoroughly analyzed. • The oxygen-containing functional groups play a crucial role in the pyrolysis of coal. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Taking six kinds of arbors in Maoershan area of Heilongjiang Province as the research object, this paper provides theoretical data for forest fire prevention. The pyrolysis stage of holocellulose was studied by thermogravimetric analysis, the mechanism function was selected by Coats Redfern integral method, and the data were processed by Origin software to obtain the corresponding activation energy and frequency factor. The pyrolysis stage data of holocellulose were extracted, and the principal component analysis was carried out by SPSS software to rank the combustibility. The results showed that the pyrolysis process of 6 kinds of arbors’ trunk samples can be divided into water loss stage, holocellulose pyrolysis stage, lignin pyrolysis stage and carbonization stage. The descending order of activation energy in the pyrolysis stage of holocellulose in the branches and stems of 6 kinds of arbors was: Tilia amurensis Rupr., Pinus sylvestris var. mongolica Litv., Fraxinus mandshurica Rupr., Betula platyphylla Suk., Larix gmelinii Kuzen., Pinus koraiensis Sieb. et Zucc., The descending order of principal component analysis was: Tilia amurensis Rupr., Pinus koraiensis Sieb. et Zucc., Fraxinus mandshurica Rupr., Larix gmelinii Kuzen., Pinus sylvestris var. mongolica Litv., Betula platyphylla Suk. . The two orders were different, indicating that the flammability cannot be evaluated only from the micro point of view, but should be considered from many aspects. [ABSTRACT FROM AUTHOR]

To obtain a comprehensive understanding of the qualitative and quantitative effects of the intrinsic properties of biomass on its pyrolysis characteristics and assess the behavior of agroforestry waste, thermogravimetric analyses of three representative agroforestry wastes, namely rape (Brassica campestris L.) straw (RS), apple (Malus domestica) tree branches (ATB), and pine (Pinus sp.) sawdust (PS), were carried out by pyrolysis under dynamic conditions (30 to 900 °C) at different heating rates of 5, 10, and 15 °C·min−1. Correlation analysis showed that intrinsic physicochemical properties play distinct roles in different stages of pyrolysis. The ash content was negatively correlated with the temperature range (R2) of the second stage (190–380 °C) of pyrolysis. The lignin content and the amount of pyrolysis residues (RSS) were positively correlated. Kinetic triplets, including the activation energy (Ea), pre-exponential factor (A), and reaction model [f(α)], were obtained using different methods, including the Flynn–Wall–Ozawa (FWO), Freidman, Kissinger–Akahira–Sunose (KAS), and Starink methods. The mean activation energy (Ea[mean]) for RS, ATB, and PS calculated by the different methods ranged from 167.15 to 195.58 kJ·mol−1, 195.37 to 234.95 kJ·mol−1, and 191.27–236.45 kJ·mol−1, respectively. Correlation analysis of the intrinsic physicochemical characteristics and kinetic factors of agroforestry waste showed that the minimum Ea (Ea[min]) was significantly positively correlated with heat capacity (C0) and negatively correlated with thermal diffusivity (D). The Ea[mean] and the maximum value of Ea (Ea[max]) significantly positively correlated with the sum content of cellulose and lignin, indicating that the contents of cellulose and lignin determines the energy required for the pyrolysis process of agroforestry waste. The mechanism of degradation involves the diffusion model (D1, D2, and D3), the growth model (A4), and the geometrical contraction model (R3). These results indicate that the pyrolysis of agroforestry waste is a complex process due to the heterogeneity of its intrinsic physicochemical properties. [ABSTRACT FROM AUTHOR]

Pyrolysis property is an important safety issue for asphalt materials. It is important to study the asphalt pyrolysis properties for selecting flame-retarding technology to improve the fire safety of asphalt materials. Differential scanning calorimeter–thermogravimetry–Fourier-transform infrared spectroscopy was used to analyze the main pyrolysis temperature range, thermal effects, and emitted volatiles of saturates, aromatics, resins and asphaltenes (SARA) fractions. The microscopic morphology, the elemental compositions and their contents of each SARA fraction pyrolysis residues were tested by environmental scanning electron microscope–energy-dispersive spectrometer. The results indicate that main pyrolysis temperature range of SARA fractions is 250–550 °C, of which saturates have the lowest initial pyrolysis temperature, successively followed by aromatics, resins and asphaltenes. Also, SARA fraction pyrolysis processes are mainly endothermic reactions. The main volatiles in the pyrolysis of SARA fractions are alkanes and a small amount of CO, CO2 and SO2. Finally, the morphology and their elemental compositions of pyrolysis residues of SARA fractions are different. Among them, the proportion of O element is decreased from saturates to aromatics, resins and asphaltenes while the proportion of C is basically increased. [ABSTRACT FROM AUTHOR]

The rational disposal of waste biogas residue can be contributed to the resource utilization rate of low-rank coal. In this study, a co-pyrolysis investigation was performed on the long-flame coal and biogas residue that mixed in equal proportions, in order to clarify the effect of temperature on the properties of co-pyrolysis products. A series of experiments were also carried out to improve the energy efficiency of waste biogas residue. The parameters were then measured using the gas chromatography-mass spectrometry (GC-MS) and GC. A product analysis was further made to evaluate the properties of the pyrolysis products. The experimental results showed that an outstanding synergistic effect was found in the co-pyrolysis of long-flame coal and biogas residue, according to the actual and calculated thermogravimetric curves. Interestingly, a synergistic effect was also found in the overlapping range for the pyrolysis temperature of the biogas residue and long-flame coal. The optimal range of pyrolysis temperature varied greatly to dominate the subsequent pyrolysis behavior and the thermogravimetric curve. Moreover, the presence of lignin in the biogas residue was promoted the formation of tar during co-pyrolysis. The formation of gaseous products was inhibited to determine the proportion of oil and gas in the co-pyrolysis products. As such, the yield of pyrolysis oil increased first and then decreased with the increase of temperature. Specifically, the oil yield rose from 9.23 to 12.12wt.%, and then decreased to 9.30wt.% at 700 ℃, as the pyrolysis temperature increased from 400 to 500 ℃. The water yield increased from 3.71wt.% at 400°C to 5.28wt.% at 600°C, and then decreased to 4.81wt.% at 700°C with the increase of temperature. The char yield gradually decreased with the increase of temperature, whereas, the gas yield increased moderately. The GC-MS data showed that the content of ketones decreased first and then increased, as the temperature increased. Nevertheless, the synergistic effect was inhibited the ketones that produced by the coal pyrolysis at high temperature. There was the highest relative content of mono- and bi-cyclic aromatic hydrocarbons in the pyrolysis oil at 600 °C, but the oxygen content was less. It infers that the synergistic effect was significantly improved the compounds in the co-pyrolysis oil. The gas analysis showed that the yields of H2 and CO first decreased and then increased with the increase of temperature, while the yield of CH4 increased first and then decreased. Furthermore, the yield of H2 decreased from 10.82% to 8.23% at 500°C, and then increased to 37.68% at 700°C, while the yield of CH4 increased from 400°C 9.69% of C increased to 18.28% of 500°C, and finally decreased to 16.58% of 700°C, as the temperature increased from 400 to 700°C. The high heating value of pyrolysis gas first increased, and then decreased with the increase of temperature, indicating the maximum of 15.33 MJ/m3 at 600°C. Consequently, the co-pyrolysis of biogas residue and long-flame coal can be expected as the optimal synergistic effect for the high yield and quality of pyrolysis products. [ABSTRACT FROM AUTHOR]

Polymethylmethacrylate (PMMA) is a common polymer electrolyte matrix material whose pyrolysis characteristics are vital factors affecting the development of PMMA-based polymer electrolytes. In this study, four polymer electrolytes based on PMMA were prepared. Electrochemical workstation was used to verify the electrochemical performance of PMMA-based polymer electrolytes Fourier-transform infrared spectroscopy was adopted to assess the changes of pure polymer and polymer electrolyte groups, and the synchronous thermal analyzer was used to analyze the pyrolysis characteristics of PMMA-based polymer electrolytes. The apparent activation energy of PMMA-based polymer electrolyte was calculated by Kissinger method and FWO method, and the integral method Coats–Redfern was used to determine the pyrolysis mechanism function of the main pyrolysis stage. The results revealed that PMMA-based polymer electrolytes had two or three pyrolysis stages at high temperature. The PMMA composite gel polymer electrolyte had the highest thermal stability, whereas the gel polymer electrolyte had the lowest apparent activation energy. The apparent activation energy was 235.9 and 127.8 kJ mol−1 for PMMA composite electrolyte and PMMA gel polymer electrolyte, respectively. The main pyrolysis mechanism of PMMA-based polymer electrolytes was third-order reaction and three-dimensional diffusion reaction. [ABSTRACT FROM AUTHOR]

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Bacterial cellulose (BC) is naturally degradable, highly biocompatible, hydrophilic, and essentially non-toxic, making it potentially useful as a base for creating more sophisticated bio-based materials. BC is similar to plant-derived cellulose in terms of chemical composition and structure but has a number of important differences in microstructure that could provide some unique opportunities for use as a scaffold for other functions. In this study, bacterial cellulose was alkylated and then esterified to produce a carboxymethyl bacterial cellulose (CMBC) that was then used to produce six different composite films with potential antibacterial properties. The films were assessed for antibacterial activity against Staphylococcus aureus and Escherichia coli, pyrolysis characteristics using thermogravimetric analysis (TGA), microstructure using scanning electron microscopy (SEM), and mechanical properties. The addition of nano-silver (nano-Ag) markedly improved the antimicrobial activity of the films while also enhancing the physical and mechanical properties. The results indicate that the three-dimensional reticulated structure of the bacterial cellulose provides an excellent substrate for scaffolding other bioactive materials. Thus, the nano-BC was added into the CMBC/nano-Ag composites furthermore, and then the antibacterial and mechanical properties were improved 44% for E. coli, 59% for S. aureus, and 20% for tensile strength, respectively. [ABSTRACT FROM AUTHOR]

Due to the complexity of components and high hazard of emissions, thermochemical conversions of plastics among waste-integrated circuits (ICs) are more favorable compared with the common treatment options of electronic waste (E-waste), such as chemical treatment and burning. In this study, the waste random-access memory, as the representative IC, was used to investigate the thermal degradation behaviors of this type of E-waste, including a quantitative analysis of pyrolysis characteristics and non-isothermal kinetics. The results show that the pyrolysis of the ICs can be divided into three different decomposition stages. The pyrolysis temperature and gas atmosphere play an important role in the pyrolysis reaction, and the heating rate greatly affects the rate of the pyrolysis reaction. The non-isothermal kinetic parameters and reaction mechanisms of ICs are determined using the Friedman method, Coats and Redfern (CR) method, and Kissinger method. The results show that the actual average activation energy of the pyrolysis reaction of ICs should be between 170 and 200 kJ·mol−1. The optimally fitting model for the ICs pyrolysis is the three-step parallel model consisting of the random nucleation model (Am) and reaction order model (Cn). [ABSTRACT FROM AUTHOR]

This paper is a case study on a thermal protection system in a combustion chamber of a ramjet. A multilayer passive thermal protection system (MPTPS) with carbon-phenolic material was established, and the temperature distribution and insulation performance of MPTPS were studied. The problem is that the carbon-phenolic material is pyrolyzed when subjected to high temperatures, leading to the changes in its thermal properties (e.g., density, specific heat capacity, and thermal conductivity.). Moreover, the carbon-phenolic material absorbs heat during the pyrolysis procedure of phenolic resin. Therefore, in this paper, several experimental studies were conducted on carbon-phenolic composites to investigate its pyrolysis characteristics, including tube furnace heating experiment and Py-GC-MS experiment. On the other hand, a one-dimensional multilayer transient heat conduction approach was developed, many calculations were numerically performed to study the effects of negative heat sources and the thickness of carbon-phenolic composites on the thermal insulation performance of MPTPS. As a result, the carbon-phenolic material was pyrolyzed from 200 °C, and the mass-loss rate was 25% when the heating temperature increased up to 900 °C; the negative heat source delayed the temperature rising point and decreased the outer wall temperature; the thickness of the carbon-phenolic composites affected the final outer wall mainly by conduction.

Tenbutyl peroxy-2 - ethyl hexanoate (TBPO), an important organic peroxide, is widely used as a poly - merization initiator and curing agent in the chemical industry. Its thermal instability due to the presence of the peroxide bond may incur a decomposition reaction and cause further thermal runaway. The pyrolysis characteristics of TBPO were assessed by three advanced calorimetry techniques. The apparent activation energies under dynamic and adiabatic conditions were calculated, and critical thermal safety parameters were determined. The specific distribution of the pyrolysis products of TBPO were identified by combining thermogravimetry-Fourier transform infrared spectroscopy (TG-FrIR) and gas chromatography/mass spectrometry (GC/MS), and the most likely pyrolysis mechanism was proposed. In addition, density functional theory (DFT) was used to evaluate the activation free energy and activation free enthalpy for each step of the pyrolysis process at the 83LYP/def2-TZVP calculation level, and kinetic calculations at different temperatures were performed by using the conventional transition state theory. The theoretical simulation results were found to be in good agreement with the experimental data. The findings of this study can provide a favorable reference to forestall thermal safety accidents in the actual storage, transportation, and operation of TBPO. [ABSTRACT FROM AUTHOR]

The effect of composite additives on the pyrolysis characteristics of microalgae (Dunaliella salina) was studied by microwave-assisted pyrolysis system. The composite additive was blended by SiC and CaO. The three cases, i.e. different kinds of additives (single additive and composite additive), different addition amounts (5%, 10%, 15%, 20%, and 25%) of composite additives, and different blending ratios (SiC/CaO = 0:10, 3:7, 5:5, and 7:3) were investigated. The results show that when the composite additive was 15% and the blending ratio of SiC/CaO = 5:5, the average weight loss rate (Rv) and weight loss rate for the second peak (Rp2) were maximum, while the final time detected as weight stabilization (tf) and the time corresponding to second peak (tp2) were minimum. Besides, SiC and CaO had a synergistic effect in this experimental condition. When the additive was 7.5% SiC, the total weight loss (Mt) and the weight loss rate for the first peak (Rp1) were maximum and the time corresponding to first peak (tp1) was minimum. The minimum Rv and Mt occurred at 7.5% CaO group. [ABSTRACT FROM AUTHOR]

A new type of dry powder fire extinguishing agent was prepared, which was called composite superfine dry powder with Aluminum Trihydrate (CSFP-ATH). The CSFP-ATH was characterized by laser particle size analysis, scanning electron microscope (SEM), thermal gravity analyzer (TGA), transform infrared spectroscopy(FTIR) analyzer and differential scanning calorimetry (DSC). The extinguishing performance of different samples was examined in a small-scale experimental platform for the liquid hydrocarbon fire. The tests were proved that the fire-extinguishing performance was as follows: CSFP-ATH > superfine ABC dry powder(SFP) > commercial ABC dry powder(CDP). Besides, the mechanism, kinetics and thermochemical changes in the reaction process were calculated by Gaussian simulation, and the reaction path of the CSFP-ATH with free radicals in the flame was predicted. Experimental and theoretical studies have been proved that the addition of Al(OH) 3 can promote the fire extinguishing performance of superfine ABC dry powder. [Display omitted] • A new composite superfine dry powder was developed using Al(OH) 3 as the additive. • Thermal Gravity Analysis (TGA) technique was used to analyze the thermal decomposition of sample powders. • Gaussian simulation was used to analyze the decomposition reaction of the Al(OH) 3. • The reasons for the enhanced suppression effect of the Al(OH) 3 were discussed. [ABSTRACT FROM AUTHOR]