Journal of Analytical and Applied Pyrolysis最新文献_第2页

Mapping of tobacco conversion characteristics in electrically heated systems: Effect of air and temperatures on the onset of combustion and formation of volatile species 绘制电加热系统中的烟草转化特征图：空气和温度对开始燃烧和形成挥发性物质的影响

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.2024.106847

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.

了解烟草热解和氧化机制是烟草科学的一个重要课题，目的是减少有毒物质的排放，并通过避免燃烧更好地控制烟草在电加热烟草制品（EHTPs）中的转化。在这项工作中，我们利用薄热电偶微定位系统对实验烟草加热装置（expTHD）进行了检测。每个 expTHD 都有一个预先设定的温度（250 至 550°C），以便研究温度对烟草转化特性和排放的影响。为了了解氧气对烟草转化和由此产生的排放的影响，在空气或 N2 下进行了膨化循环。用 expTHD 将电加热烟草制品（EHTPs）加热到不同的最终设定温度，并按照指定的膨化周期进行抽吸。8 次抽吸后，烟草在 400°C 的温度下与空气的转化明显放热，表明燃烧已被触发。在设定温度 400°C 以下，烟草转化总是净放热，这包括市售烟草加热系统（THS）在运行期间的烟草温度（通常低于 325°C）。此外，抽吸过程中的挥发物是在冷撞击器中取样的。多环芳烃（萘、菲、芘和苯并[a]芘）通过高效液相色谱-紫外荧光法进行量化。苯和甲苯通过气相色谱/质谱仪进行定量。气体（CO、CO2、CH4、H2）通过傅立叶变换红外光谱和 µGC 进行定量。所有这些物质的质量产率与 expTHD 的最终设定温度和喷射过程中使用的载气（空气或 N2）有关。即使在 250°C 的温度下，空气中 CO2 的产率也高于 N2，这表明存在一些低温氧化反应，但这些反应并未导致可检测到的放热反应。在空气条件下，从 400°C 开始，CO 的生成量骤增，表明烟草发生了燃烧。从 400°C（加热器设定温度）开始，空气（与 N2 相比）会促进苯和 PAHs 的生成。因此，在市售 THS 的运行过程中，空气不会促进这些物质的形成。

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引用次数: 0

Molecular-chemical characterization of soil organic matter in wetlands by pyrolysis-gas chromatography/mass spectrometry 利用热解-气相色谱/质谱法确定湿地土壤有机物的分子-化学特征

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-10-01 DOI: 10.1016/j.jaap.2024.106842

Wenwen Zhao , Zhongsheng Zhang , Haobo Wu , Luan Sang

The carbon cycle in ecosystems is fundamentally controlled by the composition and transformation of organic molecules. Alpine wetland soils have enormous carbon storage, but they are sensitive to climate change, and can easily shift from carbon sink to carbon source. However, we currently lack understanding in molecular-chemical composition of soil organic matter (SOM) in alpine wetlands. In this study, we tried to decipher molecular-chemical features of SOM in typical alpine wetlands using the pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Results indicated that nitrogen-containing compounds were the most abundant moieties among pyrolytic products of SOM. More than 83 % of pyrolytic moieties had a molecular weight of no more than 200 Daltons and a H/C ratio of no more than 2.0. O/C ratio of most pyrolytic products were less than 0.5. A van Krevelen diagram potentially indicated that SOM in wetlands might consist of massive heterogeneous molecules where aromatic compounds and their derivatives served as the core, with aliphatic hydrocarbon molecules of varying carbon chain lengths attached externally. About 72.25 % of variances in SOM were explained by 50 pyrolytic products, of which toluene was the most important. A significantly negative relation was observed between molecular weight (MW) and abundance of pyrolytic products, while positive relations were found between H/C, O/C, and abundance of pyrolytic products. Our work implied that SOM in wetlands was mainly composed of molecules with low MW and aromatic function groups.

生态系统中的碳循环从根本上受控于有机分子的组成和转化。高山湿地土壤具有巨大的碳储量，但对气候变化非常敏感，很容易从碳汇转变为碳源。然而，我们目前对高山湿地土壤有机质（SOM）的分子化学组成缺乏了解。在这项研究中，我们尝试利用热解-气相色谱/质谱分析法（Py-GC/MS）来解读典型高山湿地中土壤有机质的分子化学特征。结果表明，在 SOM 的热解产物中，含氮化合物的含量最高。超过 83% 的热解产物分子量不超过 200 道尔顿，H/C 比值不超过 2.0。大多数热解产物的 O/C 比小于 0.5。van Krevelen 图可能表明，湿地中的 SOM 可能由大量异质分子组成，其中芳香族化合物及其衍生物是核心，外部附着不同碳链长度的脂肪烃分子。50 种热解产物解释了约 72.25% 的 SOM 变异，其中甲苯是最重要的热解产物。分子量（MW）与热解产物的丰度呈明显的负相关，而 H/C、O/C 与热解产物的丰度呈正相关。我们的研究表明，湿地中的 SOM 主要由低分子量和芳香功能基团的分子组成。

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引用次数: 0

Viscosity reduction of heavy oil based on rice husk char-based nanocatalysts of NiO/Fe2O3 基于稻壳炭的 NiO/Fe2O3 纳米催化剂降低重油粘度

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-10-01 DOI: 10.1016/j.jaap.2024.106788

Ruiqi Liu , Liqiang Zhang , Xinlu Han, Yiya Wang, Jinyu Li, Chenxing Huang, Xinwei Wang, Riyi Lin

In recent years, catalytic hydrothermal cracking has gained significant attention as an effective technology for reducing the viscosity of heavy oil in the field of heavy oil recovery. However, the current catalyst temperature window is relatively high, leading to high energy consumption in heavy oil extraction. The development of catalysts that can effectively reduce the viscosity of heavy oil at low temperatures is important to reduce energy consumption in the thermal recovery process of heavy oil. Biochar-based catalysts exhibit good low-temperature activity. Therefore, this study used modified rice husk char as a carrier to develop NiO-RHC, Fe₂O₃-RHC, and NiO/Fe₂O₃-RHC catalysts, and investigated their performance in low-temperature catalytic viscosity reduction. Various methods were used to characterize the physical and chemical properties of the catalysts, and the effects of catalyst type and addition amounts on the catalytic viscosity reduction reaction were examined. The results showed that the catalytic performance of the dual-active component catalyst was better than that of NiO-RHC and Fe₂O₃-RHC. Under the catalysis of NiO/Fe₂O₃-RHC, the viscosity of heavy oil decreased by 81.81 %. As the catalyst addition amounts increased, the viscosity reduction rate of heavy oil also increased. The optimal catalyst addition amount was 1.00 wt%, and the heavy component content in the oil sample was reduced by 4.14 % after the catalytic reaction. Finally, the mechanism of heavy oil viscosity reduction was analyzed. It was found that the breaking of C-S bonds was a significant factor in reducing heavy oil viscosity, and the S in H₂S mainly came from thioether and sulfoxide sulfur. This study provides valuable references for further research on low-temperature viscosity reduction in heavy oil.

近年来，在重油开采领域，催化水热裂解作为降低重油粘度的有效技术受到了广泛关注。然而，目前催化剂的温度窗口相对较高，导致重油开采能耗较高。开发能在低温下有效降低重油粘度的催化剂对于降低重油热采过程中的能耗非常重要。生物炭基催化剂具有良好的低温活性。因此，本研究以改性稻壳炭为载体，开发了 NiO-RHC、Fe2O3-RHC 和 NiO/Fe2O3-RHC 催化剂，并研究了它们在低温催化降粘过程中的性能。采用多种方法对催化剂的物理和化学性质进行了表征，并考察了催化剂类型和添加量对催化降粘反应的影响。结果表明，双活性组分催化剂的催化性能优于 NiO-RHC 和 Fe2O3-RHC。在 NiO/Fe2O3-RHC 催化下，重油粘度降低了 81.81%。随着催化剂添加量的增加，重油的降粘率也随之增加。最佳催化剂添加量为 1.00 wt%，催化反应后油样中的重组分含量降低了 4.14%。最后，分析了重油降粘的机理。研究发现，C-S 键的断裂是降低重油粘度的重要因素，而 H2S 中的 S 主要来自硫醚和亚砜硫。这项研究为进一步研究重油低温降粘提供了有价值的参考。

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引用次数: 0

Confirmation of the feasibility of using agrobyproduct biochar in thermal power plants through oxygen pyrolysis and conventional pyrolysis 通过氧气热解和传统热解确认火力发电厂使用农副产品生物炭的可行性

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-10-01 DOI: 10.1016/j.jaap.2024.106791

Sunyong Park , Seok Jun Kim , Kwang Cheol Oh , Padam Prasad Paudel , Seon Yeop Kim , Ha Eun Kim , Jae Youl Shin , Dae Hyun Kim

This study investigates the feasibility of utilizing agrobyproduct biochar as a substitute for fossil fuels in thermal power plants by comparing oxygen-rich and oxygen-lean pyrolysis processes. The biomass types examined include soybean pods (BE), bamboo (BB), and wood pellets (WP). Results demonstrate that oxygen-lean pyrolysis at high temperatures enhances biochar's carbon content and energy density. Mass yields varied, with WP showing the highest yield at 500℃ under oxygen-lean conditions. Elemental analysis indicated increased carbon content and improved fuel properties with higher pyrolysis temperatures. Proximate composition analysis revealed decreased volatile matter and increased fixed carbon and ash content, leading to higher fuel ratios. Calorific values increased significantly across all biomasses, particularly under oxygen-lean conditions. Gas analysis showed significant changes in O₂, CO₂, and CO concentrations with temperature variations. Combustion indices and physical properties like aromaticity and Hardgrove grindability index improved with higher temperatures. Optimal pyrolysis conditions were identified as 325℃ for WP, 350℃ for BB, and 300℃ for BE, with BE also performing well at 500℃. The study concludes that optimized agrobyproduct biochar can effectively replace conventional fossil fuels, offering high energy yield and enhanced combustion properties.

本研究通过比较富氧和缺氧热解过程，探讨了利用农副产品生物炭替代火力发电厂化石燃料的可行性。研究的生物质类型包括豆荚（BE）、竹子（BB）和木质颗粒（WP）。结果表明，在高温下进行缺氧热解可提高生物炭的含碳量和能量密度。生物炭的质量产量各不相同，其中 WP 在 500℃的缺氧条件下产量最高。元素分析表明，热解温度越高，碳含量越高，燃料性能越好。近似成分分析表明，挥发性物质减少，固定碳和灰分含量增加，从而提高了燃料比率。所有生物质的热值都有明显提高，尤其是在缺氧条件下。气体分析表明，随着温度的变化，氧气、二氧化碳和一氧化碳的浓度也发生了显著变化。燃烧指数和物理性质（如芳香度和 Hardgrove 可磨性指数）随着温度的升高而提高。经确定，WP 的最佳热解条件为 325℃，BB 为 350℃，BE 为 300℃，BE 在 500℃时也表现良好。研究得出结论，经过优化的农副产品生物炭可以有效地替代传统化石燃料，提供高能量并增强燃烧性能。

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引用次数: 0

Base-acid tandem catalytic upgrading of coal pyrolysis volatiles: The effects of alkaline earth oxides and modified HZSM-5 zeolites 煤热解挥发物的碱-酸串联催化升级：碱土氧化物和改性 HZSM-5 沸石的影响

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-10-01 DOI: 10.1016/j.jaap.2024.106804

Li Zhang , Hang Yang , Qinglong Tan , Jiehan Zhang , Jinze Dai , Zhaohui Chen

Catalytic upgrading of coal pyrolysis volatiles is a promising technology to bolster the production of value-added chemicals from coal. To optimize product distribution and mitigate catalyst deactivation, this work investigated tandem catalysts combining the upper alkaline earth oxides (CaO or MgO) with the lower modified HZSM-5 (mesopore creation and Ga loading). The pre-cracking of volatiles over CaO or MgO lowered the average molecule size of tar components. The diffusion properties and aromatization of these pre-cracking-derived intermediates were improved, facilitating the secondary upgrading over HZSM-5-based catalysts, promoting the formation of aromatics. The experimental results showed that tandem CaO-HZSM-5 catalysts presented better synergy to improve the tar components as compared to MgO-HZSM-5, considering the formation of aromatics in tar. In this context, the mesopore and metal Ga were introduced into HZSM-5 to further upgrade the tar quality. The mesoporous structure for HZSM-5-meso and Ga/HZSM-5-meso promoted the conversion of aliphatic hydrocarbons into aromatics. Simultaneous introduction of mesopores and Ga synergistically increased the aromatic content in tar to 41.6 % and reduced the carbon deposition to 0.88 wt%. In summary, this work elucidated the mechanism of tandem CaO-modified HZSM-5 catalysis for the upgrading of volatiles from coal pyrolysis.

煤热解挥发物的催化升级是一项前景广阔的技术，可促进煤炭增值化学品的生产。为了优化产品分布并减轻催化剂失活，本研究对上层碱土氧化物（CaO 或 MgO）与下层改性 HZSM-5 （中孔创建和镓负载）相结合的串联催化剂进行了研究。挥发物在 CaO 或 MgO 上的预裂解降低了焦油成分的平均分子尺寸。这些预裂解衍生的中间产物的扩散特性和芳香化得到了改善，从而促进了基于 HZSM-5 催化剂的二次升级，促进了芳烃的形成。实验结果表明，考虑到焦油中芳烃的形成，与 MgO-HZSM-5 相比，串联 CaO-HZSM-5 催化剂在改善焦油组分方面具有更好的协同作用。在此背景下，HZSM-5 中引入了介孔和金属镓，以进一步提高焦油质量。HZSM-5-meso 和 Ga/HZSM-5-meso 的介孔结构促进了脂肪烃向芳烃的转化。同时引入介孔和 Ga 能协同将焦油中的芳烃含量提高到 41.6%，并将碳沉积降低到 0.88 wt%。总之，这项工作阐明了串联 CaO 改性 HZSM-5 催化煤热解挥发物升级的机理。

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引用次数: 0

Production of hydrochar fuel by microwave-hydrothermal carbonisation of olive pomace slurry from olive oil industry for combustion application 通过微波水热碳化橄榄油工业中的橄榄渣浆生产水碳燃料，并将其应用于燃烧

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-10-01 DOI: 10.1016/j.jaap.2024.106801

Adnan Asad Karim , María Lourdes Martínez-Cartas , Manuel Cuevas-Aranda

This work is the first investigation on microwave-assisted hydrothermal carbonisation (MHTC) of real olive pomace (OP) slurry from the olive oil industry to produce hydrochars with improved fuel properties for combustion applications (e.g., in boilers). Experiments were conducted based on the central composite design of response surface methodology with two main process variables: temperature (180–250 °C) and holding time (2–30 min). Severity factors (log R₀) were calculated from the above variables and used to explain the process effect in a simpler way. Increasing the MHTC severity resulted in significant changes in the structure of OP (studied by FTIR and NMR analyses) as well as reductions in yield, bulk density, volatile matter, and ash content in the hydrochars. The high-severity hydrochar was positioned in the lignite zone (van Krevelen diagram). It also exhibited substantial reductions in the alkali index (86.53 %), slagging index (76.89 %), and fouling index (96.07 %) compared to the raw material. Overall, the best conditions for hydrochar production with improved combustion characteristics were found to be 250 °C for 30 min (HHV = 28.45 MJ/kg, energy densification ratio = 1.25, equilibrium moisture content = 31.1 mg/g, comprehensive combustibility index = 2.94 × 10⁻⁷%² min⁻² ºC⁻³). These properties indicate that high-severity hydrochars could be utilised as biofuels for energy applications.

这项研究首次对橄榄油工业中真正的橄榄渣（OP）浆料进行微波辅助水热碳化（MHTC），以生产出具有更佳燃料特性的水成渣，用于燃烧应用（如锅炉）。实验基于响应面方法的中心复合设计，有两个主要工艺变量：温度（180-250 °C）和保温时间（2-30 分钟）。根据上述变量计算出严重性因子（log R0），并用更简单的方法解释过程效应。提高 MHTC 的严重程度会导致 OP 结构发生显著变化（通过傅立叶变换红外光谱和核磁共振分析进行研究），并降低水炭素的产量、体积密度、挥发物和灰分含量。严重程度高的水炭位于褐煤区（van Krevelen 图）。与原料相比，它的碱指数（86.53 %）、结渣指数（76.89 %）和结垢指数（96.07 %）也大幅降低。总体而言，250 °C、30 分钟（HHV = 28.45 MJ/kg，能量致密化比率 = 1.25，平衡水分含量 = 31.1 mg/g，综合燃烧指数 = 2.94 × 10-7%2 min-2 ºC-3）是生产具有更好燃烧特性的水炭的最佳条件。这些特性表明，高硬度水煤浆可用作能源应用领域的生物燃料。

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引用次数: 0

Converting corncob to caking materials via hydro-modification in a subcritical water and carbon monoxide (H2O–CO) system 在亚临界水和一氧化碳（H2O-CO）系统中通过水改性将玉米芯转化为结块材料

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-10-01 DOI: 10.1016/j.jaap.2024.106841

Qi Wang , Tiankai Zhang , Yuqiong Zhao , Wuxia Zhang , Zhifen Yang , Yongfa Zhang

China faces a long-term shortage of high-quality coking coal. Low-sulfur, low-ash biomass resources from agricultural and forestry waste are potential substitutes due to their low cost and environmental friendliness. This study applies a subcritical water-carbon monoxide (H₂O-CO) treatment for this purpose, finding that transforming corncob leads to a significant increase in its caking index, aligning with the standards of premium coking coal. This paper analyzes the main structural changes and removal patterns during corncob modification using elemental analysis, ¹H NMR, ¹³C NMR, and XPS. The results show that the modified corncob products mainly contain three elements: carbon (C), hydrogen (H), and oxygen (O). The C/H and H/O ratios are positively correlated with the caking index. The modified corncob products are rich in polycyclic aromatic hydrocarbon compounds with aliphatic side chain structures; these mainly drive the caking property transformation of the biomass. The active hydrogen produced by the water-gas shift reaction is an important hydrogen source for the modification reaction, it more easily combines with the CO single bonds in corncob. This facilitates the material transformation into substances such as xylo-oligosaccharides and gluco-oligosaccharides in the modified liquid products. Synchronizing the active hydrogen provision with the cleavage rate of chemical bonds in the corncob’s structural units is key to enhancing the modification process and elevating the caking properties. This research broadens the list of effective ways to utilize biomass resources, enriches the basic theory of biomass hydrogenation conversion process, and provides a reference for the processing and utilization of other carbon-based materials.

中国长期面临优质炼焦煤短缺的问题。来自农业和林业废弃物的低硫、低灰生物质资源因其低成本和环保性而成为潜在的替代品。为此，本研究采用了亚临界水-一氧化碳（H2O-CO）处理方法，发现对玉米芯进行转化可显著提高其结块指数，使其符合优质炼焦煤的标准。本文利用元素分析、1H NMR、13C NMR 和 XPS 分析了玉米芯改性过程中的主要结构变化和去除模式。结果表明，改性后的玉米芯产品主要含有三种元素：碳（C）、氢（H）和氧（O）。碳/氢比和氢/氧比与结块指数呈正相关。改性玉米芯产品富含具有脂肪族侧链结构的多环芳烃化合物，这些化合物是生物质结块特性转变的主要驱动力。水气变换反应产生的活性氢是改性反应的重要氢源，它更容易与玉米芯中的 CO 单键结合。这有利于改性液体产品中的物质转化为木寡糖和葡寡糖等物质。使活性氢的提供与玉米芯结构单元中化学键的裂解速度同步，是增强改性过程和提高结块性能的关键。该研究拓宽了生物质资源利用的有效途径，丰富了生物质加氢转化过程的基础理论，为其他碳基材料的加工利用提供了参考。

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引用次数: 0

Recovery of carbon fiber from carbon fiber reinforced polymer waste via microwave molten-carbonate pyrolysis 通过微波熔融碳酸盐热解从碳纤维增强聚合物废料中回收碳纤维

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-10-01 DOI: 10.1016/j.jaap.2024.106840

Junjie Shu , Lei Xu , Yiyao Ren , Shijie Xiao , Qun Wei , Cheng Xie , Yongfen Sun , Junyu Lu , Lei Li , Zhigang Shen

In recent years, the increased use of carbon fiber-reinforced polymer (CFRP) composites has led to a significant rise in waste production. To address this issue, a recycling method using microwave molten salt pyrolysis-oxidation has been proposed to efficiently process CFRP and obtain regenerated carbon fibers (RCFs) under the combined effect of microwave and Na₂CO₃/K₂CO₃/Li₂CO₃ composite molten salt. The mechanism of microwave molten salt pyrolysis was examined in conjunction with the pyrolysis products (pyrolysis oil and gas), furthermore, the microwave molten salt pyrolysis process was optimized. The causes of the changes in the mechanical characteristics and wettability of carbon fibers (CFs) were additionally investigated and analyzed. The RCFs recovered from previous composite materials were processed into new composite materials and mechanically tested to assess their reusability. The study found that using microwave pyrolysis at 350°C for 10 min followed by oxidation at 450°C for 20 min resulted in recovered carbon fibers (RCFs) that retained 98.81 % of the tensile strength of the virgin carbon fibers (VCFs). Additionally, the RCFs showed a tensile modulus enhancement of 14.70 %, with the recovery ratio of carbon fibers as high as 98.44 %. Pyrolysis generates combustible gases like hydrogen (H₂), carbon monoxide (CO), and alkanes, alongside products primarily composed of phenols and aromatic compounds. The recycling method can quickly recover high-performance carbon fibers and valuable pyrolysis by-products from CFRP waste, making them highly valuable for resource recycling and the sustainable development of carbon fiber materials.

近年来，随着碳纤维增强聚合物（CFRP）复合材料使用量的增加，废弃物的产生量也随之大幅上升。针对这一问题，有人提出了一种利用微波熔盐热解-氧化的回收方法，在微波和 Na2CO3/K2CO3/Li2CO3 复合熔盐的共同作用下，高效处理 CFRP 并获得再生碳纤维（RCF）。结合热解产物（热解油和气）对微波熔盐热解机理进行了研究，并对微波熔盐热解工艺进行了优化。此外，还调查和分析了碳纤维（CF）机械特性和润湿性发生变化的原因。从以前的复合材料中回收的 RCF 被加工成新的复合材料，并对其进行机械测试，以评估其可再利用性。研究发现，在 350°C 下微波热解 10 分钟，然后在 450°C 下氧化 20 分钟后，回收的碳纤维 (RCF) 的抗拉强度保持了原始碳纤维 (VCF) 的 98.81%。此外，RCF 的拉伸模量提高了 14.70%，碳纤维回收率高达 98.44%。热分解会产生氢气（H2）、一氧化碳（CO）和烷烃等可燃气体，以及主要由苯酚和芳香族化合物组成的产物。该回收方法可从 CFRP 废料中快速回收高性能碳纤维和有价值的热解副产品，因此对资源回收利用和碳纤维材料的可持续发展具有很高的价值。

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引用次数: 0

An overview of catalytic pyrolysis of plastic waste over base catalysts 基础催化剂催化热解塑料废弃物概述

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-10-01 DOI: 10.1016/j.jaap.2024.106828

Neng T.U. Culsum , Agus Kismanto , Prima Zuldian , Nina K. Supriatna , Samdi Yarsono , Lan M.T. Nainggolan , Alfonsus A. Raksodewanto , Oni Fariza , Fahruddin J. Ermada , Dea G.D. Saribu , Munawar Khalil , Grandprix T.M. Kadja

Excessive plastic consumption has enormous environmental consequences, including global climate change, the accumulation of non-biodegradable substances, and the depletion of fossil fuel resources. Accordingly, sustainable treatment of waste plastics must be prioritized to achieve a greener world while generating valuable energy products. Pyrolysis has been proven to be an environmentally friendly strategy for recycling plastic waste. In addition, the employment of catalysts in the pyrolysis process, particularly base catalysts, can improve the quality of the products. Base catalysts are highly selective for the formation of alkenes and aromatic hydrocarbons. In addition, the basicity of the catalyst can influence the pyrolysis products. Catalysts with lower basicity promote the formation of aldehydes and ketones, whereas catalysts with strong basicity can encourage hydrocarbon production. In addition, base catalysts can enhance the quality of pyrolytic oil by decarboxylating acidic compounds. Accordingly, this review focuses on the pyrolysis of plastic waste by employing base catalysts. The correlation between catalyst features and catalytic activity in the pyrolysis of plastic waste was also emphasized.

过度消费塑料会造成巨大的环境后果，包括全球气候变化、不可生物降解物质的积累以及化石燃料资源的枯竭。因此，必须优先考虑对废塑料进行可持续处理，以实现更环保的世界，同时产生有价值的能源产品。事实证明，热解是一种回收塑料废弃物的环保策略。此外，在热解过程中使用催化剂，特别是基催化剂，可以提高产品的质量。碱性催化剂对生成烯烃和芳香烃具有高度选择性。此外，催化剂的碱性也会影响热解产物。碱性较低的催化剂会促进醛和酮的生成，而碱性较强的催化剂则会促进烃的生成。此外，碱性催化剂还能通过对酸性化合物脱羧来提高热解油的质量。因此，本综述重点关注使用碱性催化剂热解塑料废物。此外，还强调了塑料废物热解过程中催化剂特性与催化活性之间的相关性。

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引用次数: 0

Research on modeling the lignin waste molecular structure and pyrolytic reactions using ReaxFF MD method 利用 ReaxFF MD 方法建立木质素废料分子结构和热解反应模型的研究

IF 5.8 2区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Analytical and Applied Pyrolysis

Pub Date : 2024-10-01 DOI: 10.1016/j.jaap.2024.106783

Xiankun Huang , Zhang Bai , Shuoshuo Wang , Xiaoli Zhu , Lin Mu , Liang Gong

The lack of clarity in characterizing the chemical structure model of lignin waste hinders the comprehensive understanding of its pyrolysis reaction mechanism. The characterization results revealed that the de–alkalized lignin sample contained larger amounts of aliphatic and aromatic carbons compared to carbonyl carbons. Additionally, the aliphatic carbon molecules exhibited a higher presence of oxygenated carbons. The degree of aromaticity (f_a) was determined to be 63.93 %. The resulting single–molecule structural model exhibited a molecular formula of C₃₃H₂₆O₁₁ and a molecular weight of 598.56. Furthermore, the evolutions patterns and formation pathways of primary volatile components (H₂, CH₄, CO, and CO₂) in pyrolysis reactions were revealed. The number of H₂ molecules exhibited a positive correlation with the rise in pyrolysis reaction temperature. CH₄ molecules exhibited a pattern of initially increasing and subsequently decreasing. The number of CO molecules exhibited a positive correlation with the rise in pyrolysis temperature. Conversely, the number of CO₂ molecules demonstrated an initial increase followed by a decrease as the pyrolysis temperature increased. Finally, the generation pathway analysis of pyrolysis products shows that the H₂ molecule is composed of two hydrogen atoms bonded together that have been dissociated from the carboxyl group. Alternatively, it can be produced through hydrogenation reactions involving hydrogen atoms detached from the carboxyl group and methyl groups. CH₄ is primarily generated through the reaction between –CH₃ and free hydrogen ions. CO is primarily produced through the cleavage of the carbonyl group. CO₂ is primarily produced through the cleavage of carboxyl and ester groups.

木质素废料化学结构模型的表征不清晰，阻碍了对其热解反应机理的全面了解。表征结果显示，与羰基碳相比，脱醛木质素样品含有更多的脂肪族碳和芳香族碳。此外，脂肪族碳分子中还含有较多的含氧碳。芳香度 (fa) 被测定为 63.93%。由此得到的单分子结构模型的分子式为 C33H26O11，分子量为 598.56。此外，还揭示了热解反应中主要挥发性成分（H2、CH4、CO 和 CO2）的演变规律和形成途径。H2 分子的数量与热解反应温度的升高呈正相关。CH4 分子呈现出先增加后减少的模式。CO 分子的数量与热解温度的升高呈正相关。相反，随着热解温度的升高，CO2 分子的数量表现出先增加后减少的规律。最后，热解产物的生成途径分析表明，H2 分子是由两个与羧基分离的氢原子结合而成的。另外，它也可以通过氢原子与羧基和甲基发生氢化反应生成。CH4 主要通过-CH3 和游离氢离子的反应生成。CO 主要通过羰基的裂解生成。CO2 主要通过羧基和酯基的裂解生成。

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引用次数: 0