Journal of Analytical and Applied Pyrolysis最新文献

Towards enhanced understanding of the synergistic effects between potassium and calcium in biomass catalyzed pyrolysis 进一步了解钾和钙在生物质催化热解过程中的协同效应

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-11-01 DOI: 10.1016/j.jaap.2024.106848

Zhiheng Ye , Si Li , Zhiyan Pan , Junliang Wang , Zhong-Ting Hu , Chunbao Charles Xu , Mian Hu

In this study, the influences of different parameters on the products of K-Ca synergistically catalyzed biomass pyrolysis and the possible chemical reactions during the process were investigated. Results indicated that, according to the standard Gibbs energy calculations, Ca(OH)₂ was more likely to react with carboxyl groups (precursors of CO₂) in biomass than KOH at low temperature (< 600 °C), effectively preventing the generation of CO₂. Increasing the amount of Ca(OH)₂ significantly enhanced this interaction, resulting in gradually decrease of CO₂ and CO, and remarkably promoted the generation of H₂. With a considerable decrease in the O-containing species, the hydrocarbons and phenols (phenol accounting for 49 %) became the main species in organic liquid products. For solid products, KOH can react and remove most of the oxygen-containing functional groups, while Ca(OH)₂ can fixed O-CO groups, resulting in a large amount of O-CO groups remaining. Additionally, bimetallic carbonate K₂Ca(CO₃)₂ was formed at Ca(OH)₂/KOH/soybean straw ratios below 0.25:1:2, whereas K₂Ca₂(CO₃)₃ was generated at higher ratios exceeding 0.25:1:2. At higher temperatures (> 600 °C), the O-CO groups transformed into more stable CO groups, and K₂Ca₂(CO₃)₃ decomposed into K₂Ca(CO₃)₂, which increased the content of CO via hydrogenation. As analyzed above, the mechanism of K-Ca synergistically catalyzed biomass pyrolysis was elucidated.

本研究调查了不同参数对 K-Ca 协同催化生物质热解产物的影响以及过程中可能发生的化学反应。结果表明，根据标准吉布斯能计算，在低温（< 600 °C）下，Ca（OH）2 比 KOH 更容易与生物质中的羧基（CO2 的前体）发生反应，从而有效地阻止了 CO2 的生成。增加 Ca(OH)2 的用量可显著增强这种相互作用，从而使 CO2 和 CO 逐渐减少，并显著促进 H2 的生成。随着含 O 物种的大量减少，烃类和酚类（苯酚占 49%）成为有机液体产物的主要物种。对于固体产物，KOH 可以反应并去除大部分含氧官能团，而 Ca(OH)2 则可以固定 O-CO 基团，从而使大量 O-CO 基团得以保留。此外，当 Ca（OH）2/KOH/大豆秸秆的比例低于 0.25:1:2 时，会生成双金属碳酸盐 K2Ca（CO3）2，而当比例超过 0.25:1:2 时，则会生成 K2Ca2（CO3）3。在较高温度（> 600 °C）下，O-CO 基团转化为更稳定的 CO 基团，K2Ca2(CO3)3 分解为 K2Ca(CO3)2，通过氢化增加了 CO 的含量。通过上述分析，阐明了 K-Ca 协同催化生物质热解的机理。

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引用次数: 0

Study on the aging behavior and mechanism of nitrile rubber composites in combined radiation-thermal environments 丁腈橡胶复合材料在辐射热联合环境中的老化行为和机理研究

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-11-01 DOI: 10.1016/j.jaap.2024.106865

Ruiyang Dou, Yiqian Zhang, Zhendong Huang, Qiang Liu, Wei Huang, Xianfu Meng, Hongbing Chen

This contribution investigates the aging property changes and mechanism of nitrile rubber (NBR) under the combined radiation-thermal environments in the N₂ atmosphere. Aging resulted in a decrease in elongation at break from 309.01 % to 64.74 %, an increase in modulus of elasticity from 3.84 MPa to 9.09 MPa, and a slight increase in thermal stability. The crosslink density increases and the mass loss of the sample is reduced, while the chemical structure of the sample surface is almost intact. By gas-phase infrared spectroscopy, the irradiation aging-induced gases from NBR were also analyzed, including CO₂, CO, and alkanes (CH₄, C₂H₆, C₃H₈). This indicates that chain scission and pendant group removal also take place, whereas chain breaking primarily occurs at the macromolecular chain end. The above degradation reactions and the decomposed additives account for the generated trace amount of small molecule gas products. These findings suggest that the primary aging mechanisms of NBR are the cross-linking of macromolecular chains and additive loss. Furthermore, radiation and thermal have a synergistic effect on NBR aging, and this effect has a threshold temperature that is clearly between 50 °C and 70 °C. The synergistic effect of additive cleavage is only apparent at temperatures above 65 °C under radiation-thermal conditions.

这篇论文研究了丁腈橡胶（NBR）在 N2 大气中的辐射热联合环境下的老化特性变化及其机理。老化导致断裂伸长率从 309.01 % 下降到 64.74 %，弹性模量从 3.84 兆帕增加到 9.09 兆帕，热稳定性略有提高。交联密度增加，样品的质量损失减少，而样品表面的化学结构几乎保持不变。通过气相红外光谱，还分析了 NBR 的辐照老化诱导气体，包括 CO2、CO 和烷烃（CH4、C2H6、C3H8）。这表明，链的断裂和悬垂基团的脱除也会发生，而链的断裂主要发生在大分子链的末端。上述降解反应和分解的添加剂是产生微量小分子气体产物的原因。这些发现表明，丁腈橡胶的主要老化机制是大分子链的交联和添加剂的损失。此外，辐射和热对丁腈橡胶的老化具有协同效应，这种效应的临界温度明显介于 50 °C 和 70 °C 之间。在辐射热条件下，添加剂裂解的协同效应只有在温度高于 65 °C 时才会显现。

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引用次数: 0

Research on the dynamics and mechanism of thermal cracking of coal-based endothermic hydrocarbon fuels 煤基内热烃类燃料热裂解动力学与机理研究

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-11-01 DOI: 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 E_a=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.

当燃料温度超过超临界温度时，内热烃类燃料（EHF）的热裂解在内热过程中起着重要作用。为深入了解煤基碳氢燃料的热裂解行为，本研究通过静态热裂解实验探讨了不同温度下煤基碳氢燃料的热裂解规律和反应机理，并根据产物分布建立了包含34个物种和24步反应的全分子反应动力学模型。结果表明，在 450℃ 至 500℃ 的温度范围内，燃料的气相产率从 8% 线性上升至 56%，转化率高达 96.1%。热裂解的动力学反应符合一级动力学方程，裂解速率常数k介于1.08×10-4∼7.92×10-4 s-1之间，活化能Ea=184.47±11.5 kJ∙mol-1，前驱因子lnA=21.61±3.0。气相产物包括氢气、甲烷、乙烷、乙烯、丙烷和丁烷。液相产物包括石蜡、十氢烷基萘和芳香烃。随着裂解深度的增加，燃料支化程度先增加后减少，最高可达 0.33。石蜡和烷基十氢萘逐渐转化为烯烃、环烯烃、苯、萘、茚、芴和芘等化合物。根据产物分布，推测煤基 EHF 热裂解的反应机理包括单分子 β 裂解、双分子 F-S-S、分子内 H-转移、环化和异构化机理。

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引用次数: 0

Highly efficient catalytic hydrocracking of East Inner Mongolia lignite and lignite-related model compounds through selective cleavage of aryl C-O bonds 通过选择性裂解芳基 C-O 键高效催化内蒙古东部褐煤和褐煤相关模型化合物的加氢裂化

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-11-01 DOI: 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.

通过选择性裂解芳基 C-O 键对褐煤进行高效催化加氢裂化以生产有价值的燃料和化学品是一种前景广阔但极具挑战性的方法。研究人员在镍基催化剂上进行了褐煤和褐煤相关模型化合物的催化加氢裂化反应。结果表明，随着反应条件的不断优化，苄基苯基醚和二萘醚中的芳基 C-O 键被优先裂解，随后生成的芳香族单体被氢化。此外，还实现了模型化合物的完全转化和单体产物的 100% 选择性。密度泛函理论计算表明，苄基苯基醚中的两个苯环稳定地水平吸附在镍位点上，可以降低醚氧键周围的电子云密度，减弱其解离能，从而促进芳基 C-O 键的裂解。成分分析和结构表征表明，通过选择性裂解 C-O 键、有效去除含氧结构和裂解芳香环上的侧链基团，催化褐煤加氢裂化后主要产生了芳香烃（50.02%）。最重要的是，该研究提出了一种可能的机理，即 H2 和 H---H 的异解裂解产生的 H+ 物种是主要的活性氢物种，致力于裂解 C-O 键，而 H---H 物种则倾向于随后的芳香环氢化。

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引用次数: 0

A multi-step kinetics study on Chang-7 shale pyrolysis: Impact of shale inherent minerals Chang-7 页岩热解多步骤动力学研究：页岩固有矿物的影响

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-11-01 DOI: 10.1016/j.jaap.2024.106860

Hao Lu, Qiuyang Zhao, Yanlong Zhang, Zhiwei Song, Shuoyu Zhang, Yu Dong, Hui Jin, Liejin Guo

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.

热解是油页岩就地转化和地面蒸馏的重要工艺。然而，固有矿物对页岩热解的影响尚不清楚。本研究通过对动力学和热力学参数的综合评估，分析了不同固有矿物对长-7 油页岩热解的影响，长-7 油页岩以其低碳酸盐、高硅酸盐和高黄铁矿含量而著称。利用双高斯方法，将 350℃ 至 600℃ 的热解过程分解为三个不同的过程--沥青、角质和黄铁矿热解。热力学结果表明，热解是内热和非自发的。矿物大大降低了热解活化能。页岩与角质的热解活化能之比随着碳酸盐与硅酸盐含量比的增加而增加。主图分析表明，矿物的去除使反应模型从收缩几何模型（Rn）转变为扩散模型（Dn）。反应模型的这一转变是由于脱矿和有机物分解形成了孔隙，促进了热量和活化分子向颗粒内部的扩散，这一点已通过孔隙率测定得到证实。这项工作深入了解了固有矿物对页岩热解的影响，有利于高效开发和利用油页岩资源。

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引用次数: 0

Reaction kinetics dominated by melt decomposition mechanism: Intrinsic pyrolysis of insensitive HTPE polyurethane and the efficient inter-reaction with AP 以熔体分解机理为主导的反应动力学：不敏感 HTPE 聚氨酯的本征热解以及与 AP 的高效相互反应

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-11-01 DOI: 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。

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引用次数: 0

A review on nitrogen transformation mechanism during biomass pyrolysis 生物质热解过程中氮转化机制综述

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-11-01 DOI: 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 NO_x precursors (e.g. NH₃, HCN, and HCNO) and high-value-added nitrogenous products (e.g. pyrroles, pyridines, and indoles). The control of NO_x 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_x precursor control, high-quality nitrogenous chemical and multifunctional N-doped carbon product preparation during thermochemical conversion of biomass.

生物质热化学转化过程会产生氮氧化物前体（如 NH3、HCN 和 HCNO）和高附加值含氮产品（如吡咯、吡啶和吲哚）。控制氮氧化物前体和调节含氮化学物质对环境保护和生物质资源利用具有重要意义。然而，目前生物质热解的氮转化机理尚不清楚，不利于热解产物的调控。本综述介绍了常见富氮生物质的元素组成、生化组成及氮转化方向。总结了典型模型化合物（谷氨酸、天冬氨酸、苯丙氨酸、脯氨酸和 2,5-二酮哌嗪）和主要生物质成分热解过程中氮转化特征的进展。分析了热解参数（温度、加热速率）、催化剂和气氛等实验条件对氮迁移的影响。最后，就生物燃料中的氮减排和含氮产品中的氮富集提出了氮调节策略和未来研究方向。本综述可为生物质热化学转化过程中的氮氧化物前体控制、高品质含氮化学品和多功能掺氮碳产品制备提供建议。

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引用次数: 0

Lithium-ion batteries pitch-based carbon anode materials: The role of molecular structures of pitches 锂离子电池沥青基碳负极材料：沥青分子结构的作用

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-11-01 DOI: 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.

为了解煤沥青（CTP）分子构型对碳化反应机理及后续碳化产物储锂性能的影响，研究人员对四种不同分子结构的煤沥青进行了液相和固相碳化处理，并测试了其碳化产物作为锂离子电池（LIB）负极材料的电化学性能。结果表明，具有六角环、人字边和长烷基侧链的 CTP-1 在热解过程中提供了大量自由基，促进了芳香分子的平行排列。CTP-3 中芳香分子的特殊加成模式（线性和非线性同时）会在碳化产物中产生大量边缘碳和表面缺陷。高粘度和扶手椅边缘降低了 CTP-4 分子的反应活性，CTP-4 中环状和含氧芳烃的存在也降低了碳堆的取向和微观结构的平整度。最终产品的电化学性能存在显著差异。其中，CTP-1-M-1400 在 0.1 A g-1 条件下的比容量为 349 mAh g-1，显示出卓越的循环性能。大量锂离子（约 39.2 %）储存在 CTP-3-M-1400 的边缘和表面。而大量锂离子（约占 23.5%）储存在 CTP-4-M-1400 的微空间中。此外，CTP-4-M-1400 中过多的结构缺陷和含氧基团也会导致容量保持率下降。

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引用次数: 0

Study on common amino acid pyrolysis products and analysis of pyrolysis products from interaction with aspartic acid 常见氨基酸热解产物研究及与天冬氨酸相互作用的热解产物分析

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-11-01 DOI: 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。

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引用次数: 0

An inclusive experimental and kinetic understanding of the slurry phase hydroprocessing of crude oil with an active dispersed catalyst to obtain refined fuel 用活性分散催化剂对原油进行淤浆相加氢处理以获得精炼燃料的实验和动力学综合理解

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-11-01 DOI: 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.

工业重心从燃料转向化学品，促使研究人员为催化裂化装置寻找合适的石化原料。目前，淤浆相加氢处理是工业家利用分散催化剂升级原油的一大福音。通过淤浆相反应获得的加氢处理原油可防止催化裂化催化剂装置迅速中毒，因为原油中的大部分杂质（如沥青质、树脂、重金属、硫磺等）已被去除。本研究提出了反应温度和时间对原油加氢处理的影响。首先，在 420 °C 和 120 巴氢压条件下对三种不同形式的无支撑三金属 NiMoW 催化剂进行了筛选，即合成催化剂 (CAT1)、硫化催化剂 (CAT2) 和油溶性硫化催化剂 (CAT3)。根据较重烃类馏分向较轻烃类馏分的更高转化率筛选出最佳催化剂（CAT3）后，在氢气压力（120 巴）、不同反应温度（410、420、430 °C）和反应时间（3、4 和 5 小时）下对原油加氢处理进行了详细的实验研究。随着温度从 410 ℃ 升至 430 ℃，虽然较重馏分的转化率提高了，但焦炭重量百分比的增加限制了在原油浆液加氢处理中使用极高的温度。在 420 °C 和 120 bar H2 压力下，CAT1 催化剂显示重质真空瓦斯油（450 °C ）的重量百分比从 20.05% 降至 11.1%，而中间馏分油的重量百分比从 37.02% 升至 50.4%。使用 CAT2 催化剂时，重质 VGO 从 20.05 wt% 降至 9.3 wt%，中间馏分从 37.02 wt% 增加至 52.1 wt%。CAT3 催化剂导致重质 VGO 从 20.05 wt% 降至 7.1 wt%，中间馏分从 37.02 wt% 增加至 55.2 wt%，这表明油溶性催化剂对于获得更高质量的石油催化裂化原料非常重要。为了更好地了解反应途径，还进行了动力学研究。在动力学研究的基础上，确定了与每种碳氢化合物馏分相关的活化能，并在工作中进行了介绍。迄今为止，还从未有过如此详细的研究，涵盖了所有这些有价值的参数以及动力学研究，这也是我们工作的新颖之处。

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