Pub Date : 2024-11-01DOI: 10.1016/j.jaap.2024.106836
Akang Liu , Chong Wang , Chongpeng Du , Louwei Cui , Yi Wang , Zengzhi He , Siyi Jing , Jiaxi Lei , Yinshang Xi , Jing Liu , Dong Li
Thermal cracking of endothermic hydrocarbon fuels (EHF) plays an important role in the endothermic process when the fuel temperature exceeds the supercritical temperature. To gain a deeper understanding of the thermal cracking behavior of EHF, this work discusses the thermal cracking law and reaction mechanism of coal-based EHF at different temperatures through static thermal cracking experiments, and establishes a total molecular reaction dynamics model containing 34 species and 24-step reactions based on product distribution. The results show that in the temperature range of 450℃ to 500℃, the gas phase yield of the fuel increases linearly from 8 % to 56 %, and the conversion rate reaches up to 96.1 %. The kinetic reaction of thermal cracking conforms to the primary kinetic equation, the cracking rate constant k is between 1.08×10−4∼7.92×10−4 s−1, the activation energy Ea=184.47±11.5 kJ∙mol−1, and the precursor factor lnA=21.61±3.0. Gas phase products include hydrogen, methane, ethane, ethylene, propane and butane. Liquid phase products include paraffins, alkyldecahydronaphthalenes and aromatic hydrocarbons. As the cracking depth increases, the degree of fuel branching first increases and then decreases, up to 0.33. Paraffins and alkyldecahydronaphthalenes are gradually converted into olefins, cyclic olefins, benzene, naphthalene, indene, fluorene and pyrene and other compounds. Based on the product distribution, the reaction mechanism of thermal cracking of coal-based EHF is speculated to include single-molecule β-cracking, bimolecular F-S-S, intramolecular H-transfer, cyclization and isomerization mechanisms.
{"title":"Research on the dynamics and mechanism of thermal cracking of coal-based endothermic hydrocarbon fuels","authors":"Akang Liu , Chong Wang , Chongpeng Du , Louwei Cui , Yi Wang , Zengzhi He , Siyi Jing , Jiaxi Lei , Yinshang Xi , Jing Liu , Dong Li","doi":"10.1016/j.jaap.2024.106836","DOIUrl":"10.1016/j.jaap.2024.106836","url":null,"abstract":"<div><div>Thermal cracking of endothermic hydrocarbon fuels (EHF) plays an important role in the endothermic process when the fuel temperature exceeds the supercritical temperature. To gain a deeper understanding of the thermal cracking behavior of EHF, this work discusses the thermal cracking law and reaction mechanism of coal-based EHF at different temperatures through static thermal cracking experiments, and establishes a total molecular reaction dynamics model containing 34 species and 24-step reactions based on product distribution. The results show that in the temperature range of 450℃ to 500℃, the gas phase yield of the fuel increases linearly from 8 % to 56 %, and the conversion rate reaches up to 96.1 %. The kinetic reaction of thermal cracking conforms to the primary kinetic equation, the cracking rate constant <em>k</em> is between 1.08×10<sup>−4</sup>∼7.92×10<sup>−4</sup> s<sup>−1</sup>, the activation energy <em>E</em><sub><em>a</em></sub>=184.47±11.5 kJ∙mol<sup>−1</sup>, and the precursor factor ln<em>A</em>=21.61±3.0. Gas phase products include hydrogen, methane, ethane, ethylene, propane and butane. Liquid phase products include paraffins, alkyldecahydronaphthalenes and aromatic hydrocarbons. As the cracking depth increases, the degree of fuel branching first increases and then decreases, up to 0.33. Paraffins and alkyldecahydronaphthalenes are gradually converted into olefins, cyclic olefins, benzene, naphthalene, indene, fluorene and pyrene and other compounds. Based on the product distribution, the reaction mechanism of thermal cracking of coal-based EHF is speculated to include single-molecule β-cracking, bimolecular F-S-S, intramolecular H-transfer, cyclization and isomerization mechanisms.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"184 ","pages":"Article 106836"},"PeriodicalIF":5.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.jaap.2024.106866
Han-Bing Gao , Yue-Lun Wang , Chen-Xiao Wang , Mei-Yue Huang , Le-Le Qiu , Jing Liang , Fang-Jing Liu , Jian Li , Jing-Pei Cao , Yun-Peng Zhao
Highly efficient catalytic hydrocracking of lignite through selective cleavage of aryl C-O bonds to produce valuable fuels and chemicals is a prospective but challenging approach. Catalytic hydrocracking reactions of lignite and lignite-related model compounds were performed over a Ni-based catalyst. The results demonstrated that the aryl C-O bonds in benzyl phenyl ether and dinaphthyl ether were preferentially cleaved and the resulting aromatic monomers were subsequently hydrogenated with continuous optimization of reaction conditions. Moreover, a complete conversion of model compounds and 100 % selectivity of monomeric products were achieved. The density functional theory calculations unraveled that the stable horizontal adsorption of both benzene rings in benzyl phenyl ether at Ni sites can reduce the electron cloud density around ether-oxygen bonds and weaken their dissociation energy, facilitating the dominant cleavage of aryl C-O bonds. Component analyses and structural characterizations indicated that aromatic hydrocarbons were mainly produced (50.02 %) after catalytic hydrocracking of lignite through the selective cleavage of C-O bonds, effective removal of oxygen-containing structure and cracking of side chain groups on aromatic rings. Most significantly, this study proposed the probable mechanism that H+ species originating from the heterolytic cleavage of H2 and H···H were the main active hydrogen species, committing to cracking C-O bonds, while H···H species were tendentious for subsequent hydrogenation of aromatic rings.
{"title":"Highly efficient catalytic hydrocracking of East Inner Mongolia lignite and lignite-related model compounds through selective cleavage of aryl C-O bonds","authors":"Han-Bing Gao , Yue-Lun Wang , Chen-Xiao Wang , Mei-Yue Huang , Le-Le Qiu , Jing Liang , Fang-Jing Liu , Jian Li , Jing-Pei Cao , Yun-Peng Zhao","doi":"10.1016/j.jaap.2024.106866","DOIUrl":"10.1016/j.jaap.2024.106866","url":null,"abstract":"<div><div>Highly efficient catalytic hydrocracking of lignite through selective cleavage of aryl C-O bonds to produce valuable fuels and chemicals is a prospective but challenging approach. Catalytic hydrocracking reactions of lignite and lignite-related model compounds were performed over a Ni-based catalyst. The results demonstrated that the aryl C-O bonds in benzyl phenyl ether and dinaphthyl ether were preferentially cleaved and the resulting aromatic monomers were subsequently hydrogenated with continuous optimization of reaction conditions. Moreover, a complete conversion of model compounds and 100 % selectivity of monomeric products were achieved. The density functional theory calculations unraveled that the stable horizontal adsorption of both benzene rings in benzyl phenyl ether at Ni sites can reduce the electron cloud density around ether-oxygen bonds and weaken their dissociation energy, facilitating the dominant cleavage of aryl C-O bonds. Component analyses and structural characterizations indicated that aromatic hydrocarbons were mainly produced (50.02 %) after catalytic hydrocracking of lignite through the selective cleavage of C-O bonds, effective removal of oxygen-containing structure and cracking of side chain groups on aromatic rings. Most significantly, this study proposed the probable mechanism that H<sup>+</sup> species originating from the heterolytic cleavage of H<sub>2</sub> and H···H were the main active hydrogen species, committing to cracking C-O bonds, while H···H species were tendentious for subsequent hydrogenation of aromatic rings.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"184 ","pages":"Article 106866"},"PeriodicalIF":5.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pyrolysis is a significant process for the in-situ conversion and aboveground retorting of oil shale. However, the impact of inherent minerals on shale pyrolysis is still unclear. This study analyzed the effect of different inherent minerals on pyrolysis of Chang-7 oil shale, which is noted for its low carbonate, high silicate, and high pyrite content, through an integrated evaluation of kinetic and thermodynamic parameters. The pyrolysis process, arranged from 350℃ to 600℃, was deconvoluted into three distinct processes—bitumen, kerogen, and pyrite pyrolysis—using the bi-Gaussian method. Thermodynamic results showed that pyrolysis was endothermic and non-spontaneous. Minerals significantly reduced the pyrolysis activation energy. The ratio of pyrolysis activation energies for shale to kerogen increased with the carbonate-to-silicate content ratio. Master plot analysis indicated that, mineral removal shifted the reaction model from the contraction geometry model (Rn) to the diffusion model (Dn). This transition in reaction model was due to the formation of pores from demineralization and organic decomposition, facilitating the diffusion of heat and activated molecules into the interior of particles, which has been confirmed by porosity determination. This work provides an in-depth understanding of the impact of inherent minerals on shale pyrolysis, which is conducive to the efficient development and utilization of oil shale resources.
{"title":"A multi-step kinetics study on Chang-7 shale pyrolysis: Impact of shale inherent minerals","authors":"Hao Lu, Qiuyang Zhao, Yanlong Zhang, Zhiwei Song, Shuoyu Zhang, Yu Dong, Hui Jin, Liejin Guo","doi":"10.1016/j.jaap.2024.106860","DOIUrl":"10.1016/j.jaap.2024.106860","url":null,"abstract":"<div><div>Pyrolysis is a significant process for the in-situ conversion and aboveground retorting of oil shale. However, the impact of inherent minerals on shale pyrolysis is still unclear. This study analyzed the effect of different inherent minerals on pyrolysis of Chang-7 oil shale, which is noted for its low carbonate, high silicate, and high pyrite content, through an integrated evaluation of kinetic and thermodynamic parameters. The pyrolysis process, arranged from 350℃ to 600℃, was deconvoluted into three distinct processes—bitumen, kerogen, and pyrite pyrolysis—using the bi-Gaussian method. Thermodynamic results showed that pyrolysis was endothermic and non-spontaneous. Minerals significantly reduced the pyrolysis activation energy. The ratio of pyrolysis activation energies for shale to kerogen increased with the carbonate-to-silicate content ratio. Master plot analysis indicated that, mineral removal shifted the reaction model from the contraction geometry model (Rn) to the diffusion model (Dn). This transition in reaction model was due to the formation of pores from demineralization and organic decomposition, facilitating the diffusion of heat and activated molecules into the interior of particles, which has been confirmed by porosity determination. This work provides an in-depth understanding of the impact of inherent minerals on shale pyrolysis, which is conducive to the efficient development and utilization of oil shale resources.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"184 ","pages":"Article 106860"},"PeriodicalIF":5.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.jaap.2024.106867
Qifa Yao , Chao Wang , Wei Yang , Dayong Li , Fanzhi Yang , Zhishuai Geng , Yunjun Luo , Min Xia
The novel insensitive HTPE (hydroxyl terminated polyether) adhesive holds a great potential application to develop the insensitive solid propellants. However, the pyrolysis kinetics and reaction mechanism of HTPE polyurethane are remained unclear. In this experimental investigation, the DTG curve of HTPE polyurethane was effectively deconvoluted into two main reaction stages via Gaussian peak fitting method, and the kinetic parameters for each pyrolysis stage were calculated. The calculation of the reaction mechanism functions indicated that both reaction stages follow an n-order reaction model with a very close n value. The overall pyrolysis process can be expressed as f(α) = (1 - α)ⁿ (n = 1.8 or 1.9). The TG-FTIR-GCMS results of online-collected gaseous products demonstrated that the pyrolysis of HTPE polyurethane is gradually decomposed from the outer layer to the inner layer, rather than being completely dominated by the kinetics of different functional groups. Localized melting of HTPE polyurethane was observed at 150 °C, moreover, it would almost completely transform into the liquid phase before the decomposition reaction occurred. Thus, it is suggested that the distinctive melt decomposition process of HTPE polyurethane alters the chemical environment even turns heat and mass transfer models of internal molecules, ultimately leading to its unique pyrolysis kinetics and reaction mechanisms. Furthermore, HTPE polyurethane could delay the first-stage pyrolysis of ammonium perchlorate (AP), but significantly promote its second-stage pyrolysis process. Therefore, HTPE polyurethane is beneficial in reducing the sensitivity of AP under thermal stimulation as well as promoting its concentrated heat release process.
新型不敏感 HTPE（羟基端聚醚）粘合剂在开发不敏感固体推进剂方面具有巨大的应用潜力。然而，HTPE 聚氨酯的热解动力学和反应机理仍不清楚。在本实验研究中，通过高斯峰拟合方法将 HTPE 聚氨酯的 DTG 曲线有效分解为两个主要反应阶段，并计算了各热解阶段的动力学参数。反应机理函数的计算表明，两个反应阶段均遵循 n 阶反应模型，且 n 值非常接近。整个热解过程可表示为 f(α) = (1 - α)ⁿ (n = 1.8 或 1.9)。在线收集的气态产物的 TG-FTIR-GCMS 结果表明，HTPE 聚氨酯的热解是从外层到内层逐渐分解的，而不是完全由不同官能团的动力学所主导。HTPE 聚氨酯在 150 °C 时出现局部熔化，而且在发生分解反应之前几乎完全转化为液相。因此，HTPE 聚氨酯独特的熔融分解过程改变了化学环境，甚至改变了内部分子的传热和传质模式，最终导致其独特的热解动力学和反应机制。此外，HTPE 聚氨酯可延缓高氯酸铵（AP）的第一阶段热解，但可显著促进其第二阶段热解过程。因此，HTPE 聚氨酯有利于降低 AP 在热刺激下的敏感性，并促进其集中放热过程。
{"title":"Reaction kinetics dominated by melt decomposition mechanism: Intrinsic pyrolysis of insensitive HTPE polyurethane and the efficient inter-reaction with AP","authors":"Qifa Yao , Chao Wang , Wei Yang , Dayong Li , Fanzhi Yang , Zhishuai Geng , Yunjun Luo , Min Xia","doi":"10.1016/j.jaap.2024.106867","DOIUrl":"10.1016/j.jaap.2024.106867","url":null,"abstract":"<div><div>The novel insensitive HTPE (hydroxyl terminated polyether) adhesive holds a great potential application to develop the insensitive solid propellants. However, the pyrolysis kinetics and reaction mechanism of HTPE polyurethane are remained unclear. In this experimental investigation, the DTG curve of HTPE polyurethane was effectively deconvoluted into two main reaction stages via Gaussian peak fitting method, and the kinetic parameters for each pyrolysis stage were calculated. The calculation of the reaction mechanism functions indicated that both reaction stages follow an <em>n</em>-order reaction model with a very close <em>n</em> value. The overall pyrolysis process can be expressed as <em>f(α) = (1 - α)ⁿ</em> (<em>n</em> = 1.8 or 1.9). The TG-FTIR-GCMS results of online-collected gaseous products demonstrated that the pyrolysis of HTPE polyurethane is gradually decomposed from the outer layer to the inner layer, rather than being completely dominated by the kinetics of different functional groups. Localized melting of HTPE polyurethane was observed at 150 °C, moreover, it would almost completely transform into the liquid phase before the decomposition reaction occurred. Thus, it is suggested that the distinctive melt decomposition process of HTPE polyurethane alters the chemical environment even turns heat and mass transfer models of internal molecules, ultimately leading to its unique pyrolysis kinetics and reaction mechanisms. Furthermore, HTPE polyurethane could delay the first-stage pyrolysis of ammonium perchlorate (AP), but significantly promote its second-stage pyrolysis process. Therefore, HTPE polyurethane is beneficial in reducing the sensitivity of AP under thermal stimulation as well as promoting its concentrated heat release process.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"184 ","pages":"Article 106867"},"PeriodicalIF":5.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.jaap.2024.106863
Chenyu Duan , Xianyao Yan , Wan Zhang , Yiran Zhang , Xinhui Ji , Zhen Huang , Huaqiang Chu
The thermochemical conversion of biomass produces NOx precursors (e.g. NH3, HCN, and HCNO) and high-value-added nitrogenous products (e.g. pyrroles, pyridines, and indoles). The control of NOx precursors and regulation of nitrogenous chemicals are of great significance for environmental protection and biomass resource utilisation. However, the nitrogen transformation mechanism of biomass pyrolysis is not clear at present, which is not conducive to the regulation of pyrolysis products. In this review, the elemental and biochemical compositions and the N transformation directions of common N-rich biomass have been introduced. The advances in nitrogen transformation characteristics during typical model compounds (glutamic acid, aspartic acid, phenylalanine, proline and 2,5-diketopiperazines) and major biomass components pyrolysis have been summarized. The effects of experimental conditions such as pyrolysis parameters (temperature, heating rate), catalysts, and atmospheres on nitrogen migration have been analysed. Finally, nitrogen regulation strategies and future research directions on nitrogen reduction in bio-fuels and nitrogen enrichment in nitrogenous products have been proposed. This review can provide suggestions for NOx precursor control, high-quality nitrogenous chemical and multifunctional N-doped carbon product preparation during thermochemical conversion of biomass.
{"title":"A review on nitrogen transformation mechanism during biomass pyrolysis","authors":"Chenyu Duan , Xianyao Yan , Wan Zhang , Yiran Zhang , Xinhui Ji , Zhen Huang , Huaqiang Chu","doi":"10.1016/j.jaap.2024.106863","DOIUrl":"10.1016/j.jaap.2024.106863","url":null,"abstract":"<div><div>The thermochemical conversion of biomass produces NO<sub>x</sub> precursors (e.g. NH<sub>3</sub>, HCN, and HCNO) and high-value-added nitrogenous products (e.g. pyrroles, pyridines, and indoles). The control of NO<sub>x</sub> precursors and regulation of nitrogenous chemicals are of great significance for environmental protection and biomass resource utilisation. However, the nitrogen transformation mechanism of biomass pyrolysis is not clear at present, which is not conducive to the regulation of pyrolysis products. In this review, the elemental and biochemical compositions and the N transformation directions of common N-rich biomass have been introduced. The advances in nitrogen transformation characteristics during typical model compounds (glutamic acid, aspartic acid, phenylalanine, proline and 2,5-diketopiperazines) and major biomass components pyrolysis have been summarized. The effects of experimental conditions such as pyrolysis parameters (temperature, heating rate), catalysts, and atmospheres on nitrogen migration have been analysed. Finally, nitrogen regulation strategies and future research directions on nitrogen reduction in bio-fuels and nitrogen enrichment in nitrogenous products have been proposed. This review can provide suggestions for NO<sub>x</sub> precursor control, high-quality nitrogenous chemical and multifunctional N-doped carbon product preparation during thermochemical conversion of biomass.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"184 ","pages":"Article 106863"},"PeriodicalIF":5.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.jaap.2024.106849
Jinru Wu , Tao Yang , Yan Song , Ning Zhao , Xiaodong Tian , Zhanjun Liu
To understand the effect of molecular configurations of coal tar pitch (CTP) on the reaction mechanism of carbonization and Li storage performance of subsequent carbonized products, four CTPs with different molecular structures are treated by liquid and solid phase carbonization and then tested the electrochemical performance of their carbonized products as anode materials for Lithium-ion batteries (LIBs). The results reveal that CTP-1 with hexagon rings, zigzag edges, and long alkyl side chains provides a large number of free radicals during pyrolysis, promoting the parallel arrangement of aromatic molecules. Special addition patterns (linear and nonlinear simultaneous) of aromatic molecular in CTP-3 generate a large number of edge carbons and surface defects in the carbonized products. The high viscosity and arm-chair edge reduce the reactivity of CTP-4 molecules, and the presence of loops and oxygenated aromatics in CTP-4 also reduces the orientation of carbon stacks and the flatness of the microstructure. The electrochemical performance of the final products shows a significant difference. Among them, CTP-1-M-1400 with a specific capacity of 349 mAh g−1 at 0.1 A g−1 displays an excellent cycling performance. Large amounts of Li-ions (about 39.2 %) are stored at the edge and surface of CTP-3-M-1400. While large number of Li-ions (about 23.5 %) are stored in the microspaces of CTP-4-M-1400. In addition, excessive structure defects and oxygen-containing groups in CTP-4-M-1400 lead to decreased capacity retention.
{"title":"Lithium-ion batteries pitch-based carbon anode materials: The role of molecular structures of pitches","authors":"Jinru Wu , Tao Yang , Yan Song , Ning Zhao , Xiaodong Tian , Zhanjun Liu","doi":"10.1016/j.jaap.2024.106849","DOIUrl":"10.1016/j.jaap.2024.106849","url":null,"abstract":"<div><div>To understand the effect of molecular configurations of coal tar pitch (CTP) on the reaction mechanism of carbonization and Li storage performance of subsequent carbonized products, four CTPs with different molecular structures are treated by liquid and solid phase carbonization and then tested the electrochemical performance of their carbonized products as anode materials for Lithium-ion batteries (LIBs). The results reveal that CTP-1 with hexagon rings, zigzag edges, and long alkyl side chains provides a large number of free radicals during pyrolysis, promoting the parallel arrangement of aromatic molecules. Special addition patterns (linear and nonlinear simultaneous) of aromatic molecular in CTP-3 generate a large number of edge carbons and surface defects in the carbonized products. The high viscosity and arm-chair edge reduce the reactivity of CTP-4 molecules, and the presence of loops and oxygenated aromatics in CTP-4 also reduces the orientation of carbon stacks and the flatness of the microstructure. The electrochemical performance of the final products shows a significant difference. Among them, CTP-1-M-1400 with a specific capacity of 349 mAh g<sup>−1</sup> at 0.1 A g<sup>−1</sup> displays an excellent cycling performance. Large amounts of Li-ions (about 39.2 %) are stored at the edge and surface of CTP-3-M-1400. While large number of Li-ions (about 23.5 %) are stored in the microspaces of CTP-4-M-1400. In addition, excessive structure defects and oxygen-containing groups in CTP-4-M-1400 lead to decreased capacity retention.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"184 ","pages":"Article 106849"},"PeriodicalIF":5.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.jaap.2024.106852
Richard Djimasbe , Mikhail A. Varfolomeev , Mohamed A. Abdelaal , Eduard A. Galiullin , Dmitry A. Feoktistov , Rustam R. Davletshin , Ameen A. Al-Muntaser , Muneer A. Suwaid , Dmitry A. Emelyanov , Aleksandr A. Rodionov , Almaz L. Zinnatullin , Alexey V. Vakhin , Irek I. Mukhamatdinov , Sergey A. Sitnov , Liliya K. Galiakhmetova , Konstantin Yu. Prochukhan
Accumulation of waste of plastic materials, formation of the oil sludge and hydrocarbons spills from household users and petroleum industries processes in nature, constitute a major danger for the environment whence, research of new effective techniques to expand the possibilities of the wastes recycling, is crucial. However, this paper focuses on the synthesis of bimetallic catalyst (BMC) based on Ni-Co supported on Al2O3 for the pyrolysis of polyethylene (PE), polyethylene terephthalate (PET) and oil sludge (OS) samples in sub and supercritical water (sub- and SCW) for fuels and low carbon syngas production. Experiments were performed in a batch reactor at the temperatures and pressure ranges 350 – 410°C and 213.7 – 268.9 bars for 1 h. Characterization of the BMC and pyrolysis products was done by XRD, XRF, SEM-EDX, TGA, FTIR, GC-MS, GC and EPR methods, respectively. The findings reveal that the yield of the total gases, including unsaturated gases, increase with the pyrolysis temperature, and are composed by C1–C4, C2=C4, H2, CO and CO2. At a temperature of 380°C it is found that, the pyrolysis of the low density PE and that of PET-II, in the absence of BMC significantly generated the C2=C4, CO and CO2 up to 6.2, 33.14 and 48.34 mol.%, through a secondary cracking and decarboxylation of PET, respectively. It is found that, the composition of the resulting liquid product from pyrolysis of PET, is mostly composed of Benzoic acids, Biphenyl and that, the Benzoic acid catalyzes the reaction of CO2 formation itself, in the absence of BMC. Thus, use of BMC reduced the rate of CO and CO2 by 2.80 and 3.5 times while that of C1, H2 and ΣC2-C4 increased to maximal of 45 mol.%, 24.63 mol.% and 44.59 mol.%, respectively. Moreover, a high conversion rate of 58.46 wt% was achieved from the PE-I, and that of liquid hydrocarbons of 47.24 wt% observed for PE-IV, at 380°C in the presence of BMC. The results revealed that most of H2 source is essentially based on the water gas shift reaction and Sabatier's. Around 43–50 wt% of water was involved in the pyrolysis of PE, and that 0.4 % of Dodecadien-1-ol and 5 % of Decanedioic acid were detected only in the liquid product using the BMC. Overall, the use of BMC for pyrolysis of samples in SCW water is beneficial for the production of H2 and C1 with the reduction of CO and CO2 emissions.
{"title":"Enhanced pyrolysis of oil sludge and polymer waste in sub and supercritical water: Production of low-carbon syngas, and liquid hydrocarbons using bimetallic catalyst based on nickel-cobalt","authors":"Richard Djimasbe , Mikhail A. Varfolomeev , Mohamed A. Abdelaal , Eduard A. Galiullin , Dmitry A. Feoktistov , Rustam R. Davletshin , Ameen A. Al-Muntaser , Muneer A. Suwaid , Dmitry A. Emelyanov , Aleksandr A. Rodionov , Almaz L. Zinnatullin , Alexey V. Vakhin , Irek I. Mukhamatdinov , Sergey A. Sitnov , Liliya K. Galiakhmetova , Konstantin Yu. Prochukhan","doi":"10.1016/j.jaap.2024.106852","DOIUrl":"10.1016/j.jaap.2024.106852","url":null,"abstract":"<div><div>Accumulation of waste of plastic materials, formation of the oil sludge and hydrocarbons spills from household users and petroleum industries processes in nature, constitute a major danger for the environment whence, research of new effective techniques to expand the possibilities of the wastes recycling, is crucial. However, this paper focuses on the synthesis of bimetallic catalyst (BMC) based on Ni-Co supported on Al<sub>2</sub>O<sub>3</sub> for the pyrolysis of polyethylene (PE), polyethylene terephthalate (PET) and oil sludge (OS) samples in sub and supercritical water (sub- and SCW) for fuels and low carbon syngas production. Experiments were performed in a batch reactor at the temperatures and pressure ranges 350 – 410°C and 213.7 – 268.9 bars for 1 h. Characterization of the BMC and pyrolysis products was done by XRD, XRF, SEM-EDX, TGA, FTIR, GC-MS, GC and EPR methods, respectively. The findings reveal that the yield of the total gases, including unsaturated gases, increase with the pyrolysis temperature, and are composed by C<sub>1</sub>–C<sub>4</sub>, C<sub>2</sub>=C<sub>4</sub>, H<sub>2</sub>, CO and CO<sub>2</sub>. At a temperature of 380°C it is found that, the pyrolysis of the low density PE and that of PET-II, in the absence of BMC significantly generated the C<sub>2</sub>=C<sub>4</sub>, CO and CO<sub>2</sub> up to 6.2, 33.14 and 48.34 mol.%, through a secondary cracking and decarboxylation of PET, respectively. It is found that, the composition of the resulting liquid product from pyrolysis of PET, is mostly composed of Benzoic acids, Biphenyl and that, the Benzoic acid catalyzes the reaction of CO<sub>2</sub> formation itself, in the absence of BMC. Thus, use of BMC reduced the rate of CO and CO<sub>2</sub> by 2.80 and 3.5 times while that of C<sub>1</sub>, H<sub>2</sub> and ΣC<sub>2</sub>-C<sub>4</sub> increased to maximal of 45 mol.%, 24.63 mol.% and 44.59 mol.%, respectively. Moreover, a high conversion rate of 58.46 wt% was achieved from the PE-I, and that of liquid hydrocarbons of 47.24 wt% observed for PE-IV, at 380°C in the presence of BMC. The results revealed that most of H<sub>2</sub> source is essentially based on the water gas shift reaction and Sabatier's. Around 43–50 wt% of water was involved in the pyrolysis of PE, and that 0.4 % of Dodecadien-1-ol and 5 % of Decanedioic acid were detected only in the liquid product using the BMC. Overall, the use of BMC for pyrolysis of samples in SCW water is beneficial for the production of H<sub>2</sub> and C<sub>1</sub> with the reduction of CO and CO<sub>2</sub> emissions.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"184 ","pages":"Article 106852"},"PeriodicalIF":5.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142703764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.jaap.2024.106843
Yishou Liu , Yi Zhang , Ziyue Tang , Yingquan Chen , Haiping Yang , Hanping Chen
Nitrogen in nitrogen-rich biomass can be converted into high-value nitrogen-containing chemicals such as pyrroles, pyridines and indoles by pyrolysis. Understanding the nitrogen transport mechanism and reaction pathways is important for the utilization of nitrogen-rich biomass. In this study, the pyrolytic reaction pathways of 16 amino acids and interaction between others with aspartic acid were analyzed by pyrolysis in a closed U-tube reactor followed by gas chromatography/mass spectrometry (GC/MS) measurements. It was found that amino acids with lighter molecular tended to produce more gases during the pyrolysis, while amino acids with heavier molecular tended to produce more liquids and solids. The gaseous products of amino acid pyrolysis mainly consisted of CO2 and some CO, of which the content of CO2 reached 86.21 % of glycine and 70.97 % of aspartic acid, respectively. Liquid oils contain a large number of nitrogen-containing heterocyclic compounds, which are mainly produced by four types of reactions: cyclisation, R group removal, polymerization, and fragmentation reforming. And it was found that aspartic acid was able to promote the changes of the three phases of pyrolysis products and the formation of characteristic products.
富氮生物质中的氮可通过热解转化为吡咯、吡啶和吲哚等高价值含氮化学品。了解氮的迁移机制和反应途径对于富氮生物质的利用非常重要。本研究通过在封闭的 U 型管反应器中进行热解，然后进行气相色谱/质谱（GC/MS）测量，分析了 16 种氨基酸的热解反应途径以及其他氨基酸与天冬氨酸之间的相互作用。结果发现，分子较轻的氨基酸在热解过程中产生的气体较多，而分子较重的氨基酸产生的液体和固体较多。氨基酸热解的气态产物主要是 CO2 和部分 CO，其中 CO2 的含量在甘氨酸和天冬氨酸中分别达到 86.21% 和 70.97%。液态油中含有大量含氮杂环化合物，主要由四种反应生成：环化、R 基脱除、聚合和裂解重整。研究发现，天冬氨酸能够促进热解产物三相的变化和特征产物的形成。
{"title":"Study on common amino acid pyrolysis products and analysis of pyrolysis products from interaction with aspartic acid","authors":"Yishou Liu , Yi Zhang , Ziyue Tang , Yingquan Chen , Haiping Yang , Hanping Chen","doi":"10.1016/j.jaap.2024.106843","DOIUrl":"10.1016/j.jaap.2024.106843","url":null,"abstract":"<div><div>Nitrogen in nitrogen-rich biomass can be converted into high-value nitrogen-containing chemicals such as pyrroles, pyridines and indoles by pyrolysis. Understanding the nitrogen transport mechanism and reaction pathways is important for the utilization of nitrogen-rich biomass. In this study, the pyrolytic reaction pathways of 16 amino acids and interaction between others with aspartic acid were analyzed by pyrolysis in a closed U-tube reactor followed by gas chromatography/mass spectrometry (GC/MS) measurements. It was found that amino acids with lighter molecular tended to produce more gases during the pyrolysis, while amino acids with heavier molecular tended to produce more liquids and solids. The gaseous products of amino acid pyrolysis mainly consisted of CO<sub>2</sub> and some CO, of which the content of CO<sub>2</sub> reached 86.21 % of glycine and 70.97 % of aspartic acid, respectively. Liquid oils contain a large number of nitrogen-containing heterocyclic compounds, which are mainly produced by four types of reactions: cyclisation, R group removal, polymerization, and fragmentation reforming. And it was found that aspartic acid was able to promote the changes of the three phases of pyrolysis products and the formation of characteristic products.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"184 ","pages":"Article 106843"},"PeriodicalIF":5.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.jaap.2024.106834
Ashutosh Rawat , Sonu Dhakla , Samir K. Maity , Ojasvi , Prem Lama
The shift of the industrial focus from fuel to chemicals has urged the researchers to obtain a suitable petrochemical feedstock for the FCC unit. Currently, the slurry phase hydroprocessing is a boon for industrialists to upgrade the crude oil using dispersed catalysts. This hydroprocessed crude oil obtained from slurry phase reaction prevents the FCC catalyst unit from getting rapidly poisoned as most of the impurities is removed from the crude oil such as asphaltenes, resins, heavy metal, sulfur etc. This study puts forward the influence of reaction temperature and time on the hydroprocessing of the crude oil. First, the screening of three separate forms of unsupported trimetallic NiMoW catalysts i.e., as-synthesized (CAT1), sulfided (CAT2), and oil-soluble sulfided (CAT3) at 420 °C and 120 bar of hydrogen pressure has been performed. After screening out the best catalyst (CAT3) based on greater conversion results of heavier hydrocarbon fractions to lighter hydrocarbon fractions, further a detailed experimental study for the hydroprocessing of crude oil under hydrogen pressure (120 bar) with varying reaction temperatures (410, 420, 430 °C) and time period (3, 4 and 5 hours) has been carried. With the rise in temperature from 410 to 430 °C, although the higher conversion of heavier fractions is obtained but the increased amount in the coke weight % restricts the use of very high temperatures for slurry hydroprocessing of crude oil. At 420 °C and 120 bar H2 pressure, CAT1 catalyst shows a reduction in heavy vacuum gas oil (>450 °C) from 20.05 wt% to 11.1 wt%, and a rise in middle distillate from 37.02 wt% to 50.4 wt%. When CAT2 catalyst is employed, a decrease in heavy VGO from 20.05 wt% to 9.3 wt% was observed with an increase in the middle distillates from 37.02 wt% to 52.1 wt%. CAT3 catalyst leads to maximum reduction in heavy VGO from 20.05 wt% to 7.1 wt% with an increase in the middle distillates from 37.02 wt% to 55.2 wt%, which shows the importance of oil-soluble catalyst to obtain better quality petro FCC feed. The kinetic study has also been performed for a better understanding of the reaction pathway. Based on the kinetic study, the activation energy associated with each hydrocarbon fraction has been determined and presented in the work. Such a detailed study covering all these valuable parameters along with kinetic study has not been presented till now which is the novelty of our work also.
{"title":"An inclusive experimental and kinetic understanding of the slurry phase hydroprocessing of crude oil with an active dispersed catalyst to obtain refined fuel","authors":"Ashutosh Rawat , Sonu Dhakla , Samir K. Maity , Ojasvi , Prem Lama","doi":"10.1016/j.jaap.2024.106834","DOIUrl":"10.1016/j.jaap.2024.106834","url":null,"abstract":"<div><div>The shift of the industrial focus from fuel to chemicals has urged the researchers to obtain a suitable petrochemical feedstock for the FCC unit. Currently, the slurry phase hydroprocessing is a boon for industrialists to upgrade the crude oil using dispersed catalysts. This hydroprocessed crude oil obtained from slurry phase reaction prevents the FCC catalyst unit from getting rapidly poisoned as most of the impurities is removed from the crude oil such as asphaltenes, resins, heavy metal, sulfur etc. This study puts forward the influence of reaction temperature and time on the hydroprocessing of the crude oil. First, the screening of three separate forms of unsupported trimetallic NiMoW catalysts i.e., as-synthesized (CAT1), sulfided (CAT2), and oil-soluble sulfided (CAT3) at 420 °C and 120 bar of hydrogen pressure has been performed. After screening out the best catalyst (CAT3) based on greater conversion results of heavier hydrocarbon fractions to lighter hydrocarbon fractions, further a detailed experimental study for the hydroprocessing of crude oil under hydrogen pressure (120 bar) with varying reaction temperatures (410, 420, 430 °C) and time period (3, 4 and 5 hours) has been carried. With the rise in temperature from 410 to 430 °C, although the higher conversion of heavier fractions is obtained but the increased amount in the coke weight % restricts the use of very high temperatures for slurry hydroprocessing of crude oil. At 420 °C and 120 bar H<sub>2</sub> pressure, CAT1 catalyst shows a reduction in heavy vacuum gas oil (>450 °C) from 20.05 wt% to 11.1 wt%, and a rise in middle distillate from 37.02 wt% to 50.4 wt%. When CAT2 catalyst is employed, a decrease in heavy VGO from 20.05 wt% to 9.3 wt% was observed with an increase in the middle distillates from 37.02 wt% to 52.1 wt%. CAT3 catalyst leads to maximum reduction in heavy VGO from 20.05 wt% to 7.1 wt% with an increase in the middle distillates from 37.02 wt% to 55.2 wt%, which shows the importance of oil-soluble catalyst to obtain better quality petro FCC feed. The kinetic study has also been performed for a better understanding of the reaction pathway. Based on the kinetic study, the activation energy associated with each hydrocarbon fraction has been determined and presented in the work. Such a detailed study covering all these valuable parameters along with kinetic study has not been presented till now which is the novelty of our work also.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"184 ","pages":"Article 106834"},"PeriodicalIF":5.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.jaap.2024.106847
M. Bechikhi , E. Masson , O. Herbinet , A. Dufour
The understanding of tobacco pyrolysis and oxidation mechanisms is an important topic for tobacco science in order to reduce the emissions of toxic species and to better control the conversion of tobacco in electrically heated tobacco products (EHTPs) by avoiding combustion. In this work, we have instrumented experimental Tobacco Heating Devices (expTHD) with a micro-positioning system of a thin thermocouple. Each expTHD has a pre-programmed set temperature (between 250 and 550°C) to be able to investigate the influence of temperature on tobacco conversion characteristics and emissions. Puffing cycles were conducted under air or N2 in order to understand the effect of oxygen on tobacco conversion and the resulting emissions. Electrically Heated Tobacco Products (EHTPs) were heated by the expTHD to the different final set temperatures, and puffs were drawn according to the specified puffing cycles. The conversion of tobacco becomes clearly exothermic with air from 400°C after 8 puffs, indicating that combustion was triggered. Below a set temperature of 400°C, the tobacco conversion is always net endothermic, which includes the tobacco temperatures of commercially available Tobacco Heating Systems (THS) during operation (typically lower than 325°C). Furthermore, the volatiles emitted during the puffing cycles were sampled in cold impingers. PAHs (naphthalene, phenanthrene, pyrene, and benzo[a]pyrene) were quantified by HPLC-UV Fluorescence. Benzene and toluene were quantified by GC/MS. Gases (CO, CO2, CH4, H2) were quantified by FTIR and µGC. The mass yields of all these species are presented as a function of the final set temperature of the expTHD and of the carrier gas used during the puffs (air or N2). CO2 yields are higher for air than for N2 even at 250°C, highlighting some low temperature oxidation reactions, but they did not lead to a detectable exothermic regime. A jump in CO formation is observed from 400°C under air, indicating combustion of the tobacco. Benzene and PAHs are promoted by air (compared to N2) from 400°C (heater set temperature). Therefore, air does not promote the formation of these species during the operation of the commercially available THS.
{"title":"Mapping of tobacco conversion characteristics in electrically heated systems: Effect of air and temperatures on the onset of combustion and formation of volatile species","authors":"M. Bechikhi , E. Masson , O. Herbinet , A. Dufour","doi":"10.1016/j.jaap.2024.106847","DOIUrl":"10.1016/j.jaap.2024.106847","url":null,"abstract":"<div><div>The understanding of tobacco pyrolysis and oxidation mechanisms is an important topic for tobacco science in order to reduce the emissions of toxic species and to better control the conversion of tobacco in electrically heated tobacco products (EHTPs) by avoiding combustion. In this work, we have instrumented experimental Tobacco Heating Devices (expTHD) with a micro-positioning system of a thin thermocouple. Each expTHD has a pre-programmed set temperature (between 250 and 550°C) to be able to investigate the influence of temperature on tobacco conversion characteristics and emissions. Puffing cycles were conducted under air or N<sub>2</sub> in order to understand the effect of oxygen on tobacco conversion and the resulting emissions. Electrically Heated Tobacco Products (EHTPs) were heated by the expTHD to the different final set temperatures, and puffs were drawn according to the specified puffing cycles. The conversion of tobacco becomes clearly exothermic with air from 400°C after 8 puffs, indicating that combustion was triggered. Below a set temperature of 400°C, the tobacco conversion is always net endothermic, which includes the tobacco temperatures of commercially available Tobacco Heating Systems (THS) during operation (typically lower than 325°C). Furthermore, the volatiles emitted during the puffing cycles were sampled in cold impingers. PAHs (naphthalene, phenanthrene, pyrene, and benzo[<em>a</em>]pyrene) were quantified by HPLC-UV Fluorescence. Benzene and toluene were quantified by GC/MS. Gases (CO, CO<sub>2</sub>, CH<sub>4</sub>, H<sub>2</sub>) were quantified by FTIR and µGC. The mass yields of all these species are presented as a function of the final set temperature of the expTHD and of the carrier gas used during the puffs (air or N<sub>2</sub>). CO<sub>2</sub> yields are higher for air than for N<sub>2</sub> even at 250°C, highlighting some low temperature oxidation reactions, but they did not lead to a detectable exothermic regime. A jump in CO formation is observed from 400°C under air, indicating combustion of the tobacco. Benzene and PAHs are promoted by air (compared to N<sub>2</sub>) from 400°C (heater set temperature). Therefore, air does not promote the formation of these species during the operation of the commercially available THS.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"184 ","pages":"Article 106847"},"PeriodicalIF":5.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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