Pub Date : 2025-12-30DOI: 10.1016/j.jaap.2025.107588
Weixuan Zhang , Lichao Ge , Hongcui Feng , Chunyao Xu , Chengxing Peng , Chen Feng , Yanquan Liu , Huiwen Liu , Yang Wang , Chang Xu
With the rapid development of the wind power industry, the accumulation of retired blades has surged, and although these blades contain recyclable composites, effective recycling methods are still limited. This study focuses on the pyrolytic recycling of glass fiber and carbon fiber reinforced epoxy composites, and systematically analyses the effect of temperature on the product properties and the properties of the recycled fibers through isothermal pyrolysis experiments at 500°C, 600°C and 800°C. The results showed that the pyrolysis products were dominated by phenolic compounds, and the high temperature promotes the conversion of macromolecules to small molecules. The residual carbon on the surface of the recovered fibers was effectively removed by post-oxidation treatment at 500 °C. However, the tensile strength of the recycled fibers decreased with increasing pyrolysis temperature, indicating a trade-off between resin removal efficiency and fiber mechanical integrity. XPS and Raman analyses revealed that higher pyrolysis temperatures increase the reactivity of residual carbon but also induce greater structural disorder in the fibers. Therefore, this study suggests that optimizing the pyrolysis recycling process requires balancing the pyrolysis temperature (e. g., favoring a moderate range around 600°C) to maximize both resin decomposition for cleaner fiber recovery and the preservation of fiber mechanical properties. In addition, the proposed epoxy resin pyrolysis conversion pathway provides a theoretical basis for understanding product distribution and controlling the process. Collectively, these findings offer crucial insights and quantitative guidelines for optimizing temperature parameters in the pyrolysis-based recycling of decommissioned wind turbine blades.
{"title":"Characteristics of pyrolysis products and recycled fiber properties of typical end-of-life wind turbine blades","authors":"Weixuan Zhang , Lichao Ge , Hongcui Feng , Chunyao Xu , Chengxing Peng , Chen Feng , Yanquan Liu , Huiwen Liu , Yang Wang , Chang Xu","doi":"10.1016/j.jaap.2025.107588","DOIUrl":"10.1016/j.jaap.2025.107588","url":null,"abstract":"<div><div>With the rapid development of the wind power industry, the accumulation of retired blades has surged, and although these blades contain recyclable composites, effective recycling methods are still limited. This study focuses on the pyrolytic recycling of glass fiber and carbon fiber reinforced epoxy composites, and systematically analyses the effect of temperature on the product properties and the properties of the recycled fibers through isothermal pyrolysis experiments at 500°C, 600°C and 800°C. The results showed that the pyrolysis products were dominated by phenolic compounds, and the high temperature promotes the conversion of macromolecules to small molecules. The residual carbon on the surface of the recovered fibers was effectively removed by post-oxidation treatment at 500 °C. However, the tensile strength of the recycled fibers decreased with increasing pyrolysis temperature, indicating a trade-off between resin removal efficiency and fiber mechanical integrity. XPS and Raman analyses revealed that higher pyrolysis temperatures increase the reactivity of residual carbon but also induce greater structural disorder in the fibers. Therefore, this study suggests that optimizing the pyrolysis recycling process requires balancing the pyrolysis temperature (e. g., favoring a moderate range around 600°C) to maximize both resin decomposition for cleaner fiber recovery and the preservation of fiber mechanical properties. In addition, the proposed epoxy resin pyrolysis conversion pathway provides a theoretical basis for understanding product distribution and controlling the process. Collectively, these findings offer crucial insights and quantitative guidelines for optimizing temperature parameters in the pyrolysis-based recycling of decommissioned wind turbine blades.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107588"},"PeriodicalIF":6.2,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880264","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}
Although the contents of the vitrinite and inertinite components in coal macerals have been applied in the process of blending coal for coking, it is well known that there are significant differences in the coking ability for coals with variable ranks in which the change of the contents of the vitrinite and inertinite components is small. Therefore, it is crucial to gain insight into the difference of coking properties of the vitrinite and inertinite components from macerals of coals with variable ranks. In this paper, the vitrinite and inertinite were enriched using a thermally assisted multi-density gradient agitation separation method, and their chemical structures characterization was carried out to obtain some useful structure parameters such as the hydrocarbon generation potential (P) by Fourier transform infrared spectroscopy technique. The relationships between structural parameters and coking properties of raw coal and vitrinite-rich were further analyzed. The results indicate that vitrinite-rich of medium-rank coal contains higher aliphatic content and has a higher P value. Conversely, inertinite-rich of medium and high rank coals contains higher aromatic content. Combining the coking indexes of coal macerals, it indicates that the weak coking ability of low-rank coal is limited by insufficient aromatic content in inertinite, while that of high-rank coal is affected by the reduction of aliphatic content in vitrinite. Therefore, it is advisable to add to low-rank weakly caking coals to offer plasticity and high-rank weakly caking coals to support carbon matrix during blending coal for coking. This study provides a valuable insight for increasing to the utilization of weakly caking coals in coking process.
{"title":"Insight into the difference of coking properties for the vitrinite and inertinite components in coal macerals with variable ranks by chemical structural characterization","authors":"Zhifang Wei , Shengfu Zhang , Wenhao Xie , Jingbo Chen , Xianyou Huang , Jianming Wang , Shuxing Qiu","doi":"10.1016/j.jaap.2025.107587","DOIUrl":"10.1016/j.jaap.2025.107587","url":null,"abstract":"<div><div>Although the contents of the vitrinite and inertinite components in coal macerals have been applied in the process of blending coal for coking, it is well known that there are significant differences in the coking ability for coals with variable ranks in which the change of the contents of the vitrinite and inertinite components is small. Therefore, it is crucial to gain insight into the difference of coking properties of the vitrinite and inertinite components from macerals of coals with variable ranks. In this paper, the vitrinite and inertinite were enriched using a thermally assisted multi-density gradient agitation separation method, and their chemical structures characterization was carried out to obtain some useful structure parameters such as the hydrocarbon generation potential (<em>P</em>) by Fourier transform infrared spectroscopy technique. The relationships between structural parameters and coking properties of raw coal and vitrinite-rich were further analyzed. The results indicate that vitrinite-rich of medium-rank coal contains higher aliphatic content and has a higher <em>P</em> value. Conversely, inertinite-rich of medium and high rank coals contains higher aromatic content. Combining the coking indexes of coal macerals, it indicates that the weak coking ability of low-rank coal is limited by insufficient aromatic content in inertinite, while that of high-rank coal is affected by the reduction of aliphatic content in vitrinite. Therefore, it is advisable to add to low-rank weakly caking coals to offer plasticity and high-rank weakly caking coals to support carbon matrix during blending coal for coking. This study provides a valuable insight for increasing to the utilization of weakly caking coals in coking process.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107587"},"PeriodicalIF":6.2,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145920736","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 : 2025-12-29DOI: 10.1016/j.jaap.2025.107586
Han-xian Meng , Ji Liu , Zhi Zhou , Wen-tao Li , Bin Hu , Zhen-xi Zhang , Qiang Lu
The catalytic steam reforming of biomass pyrolysis vapors on Ni-doped biochar (Ni/biochar) is an attractive approach to produce hydrogen. However, pyrolysis vapors consist of complex components, and their reforming mechanism remains comprehensively unclear. In this work, the steam reforming mechanism of pyrolysis vapors over Ni/biochar with acetic acid as the model compound was studied by density functional theory (DFT), wave function analysis, and transition state theory (TST) methods. Particularly, the role of steam in this process was primarily discussed. Acetic acid tends to interact with Ni/biochar by its dissociative OH adsorption at the active carbon position. The decomposition of acetic acid for forming carbon oxides and hydrogen is initiated by its CC and CH homolysis. The activation energy for CC homolysis increases with adding steam adjacent to reactive sites, while its addition promotes the CH homolysis (reducing from 203 kJ/mol to 151.5 kJ/mol) at the set temperatures, enhancing the competitiveness of hydrogen formation. The reactions of steam with acetic acid and its decomposed intermediates primarily result in the formation of methane, followed by carbon monoxide and methanol. These results can provide theoretical insights for the improvement and optimization of the pyrolysis and reforming technology of biomass to produce hydrogen.
{"title":"Steam reforming mechanism of acetic acid for hydrogen production over the Ni/biochar catalyst: The effect of steam","authors":"Han-xian Meng , Ji Liu , Zhi Zhou , Wen-tao Li , Bin Hu , Zhen-xi Zhang , Qiang Lu","doi":"10.1016/j.jaap.2025.107586","DOIUrl":"10.1016/j.jaap.2025.107586","url":null,"abstract":"<div><div>The catalytic steam reforming of biomass pyrolysis vapors on Ni-doped biochar (Ni/biochar) is an attractive approach to produce hydrogen. However, pyrolysis vapors consist of complex components, and their reforming mechanism remains comprehensively unclear. In this work, the steam reforming mechanism of pyrolysis vapors over Ni/biochar with acetic acid as the model compound was studied by density functional theory (DFT), wave function analysis, and transition state theory (TST) methods. Particularly, the role of steam in this process was primarily discussed. Acetic acid tends to interact with Ni/biochar by its dissociative O<img>H adsorption at the active carbon position. The decomposition of acetic acid for forming carbon oxides and hydrogen is initiated by its C<img>C and C<img>H homolysis. The activation energy for C<img>C homolysis increases with adding steam adjacent to reactive sites, while its addition promotes the C<img>H homolysis (reducing from 203 kJ/mol to 151.5 kJ/mol) at the set temperatures, enhancing the competitiveness of hydrogen formation. The reactions of steam with acetic acid and its decomposed intermediates primarily result in the formation of methane, followed by carbon monoxide and methanol. These results can provide theoretical insights for the improvement and optimization of the pyrolysis and reforming technology of biomass to produce hydrogen.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107586"},"PeriodicalIF":6.2,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880263","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 : 2025-12-29DOI: 10.1016/j.jaap.2025.107585
Guojie Liu , Zeqi Wang , Kejing Wu , Houfang Lu , Yangyang Yu , Chao Chen , Xin Jin , Bin Liang
Overcoming the critical challenge of low prediction accuracy (typically 15–30 %) in H2 production from thermochemical conversion of lignocellulose is essential for enhancing feedstock screening and utilization efficiency. Herein, a basic prediction model is established for traditional- and temperature-programmed alkaline thermal treatment (T-ATT and TP-ATT) of lignocellulose based on the content of three major components and their inherent H2 production. The results indicate that the H2 production from T-/TP-ATT of actual lignocellulose can be calculated by directly superimposing the H2 production of microcrystalline cellulose, xylan and lignin, with prediction error < 5 %. This is attributed to the clear secondary reaction (methanation reaction of char) and extremely low tar content observed during reaction process. Moreover, variations in lignin composition constitute the fundamental cause of increased prediction errors in H2 production for different feedstocks within same species. An innovative correction method utilizing the composition characteristics (C, H and O content) of lignin as critical parameters achieves optimal prediction of H2 production for T-/TP-ATT process. The corrected prediction model can significantly reduce the prediction errors of H2 production from unknown woody (1.1 % and 2.0 % for T-ATT and TP-ATT), herbaceous (5.0 % for T-ATT), vine (1.7 % and 3.9 % for T-ATT and TP-ATT), and hemp (4.8 % for T-ATT) feedstocks. The priority of actual lignocellulose for H2 production is hemp > woody ≥ herbaceous > vine. This study will accelerate the practical application of T-/TP-ATT technology.
{"title":"Quantifying the contribution of three major components in predicting H2 production from alkaline thermal treatment of lignocellulose","authors":"Guojie Liu , Zeqi Wang , Kejing Wu , Houfang Lu , Yangyang Yu , Chao Chen , Xin Jin , Bin Liang","doi":"10.1016/j.jaap.2025.107585","DOIUrl":"10.1016/j.jaap.2025.107585","url":null,"abstract":"<div><div>Overcoming the critical challenge of low prediction accuracy (typically 15–30 %) in H<sub>2</sub> production from thermochemical conversion of lignocellulose is essential for enhancing feedstock screening and utilization efficiency. Herein, a basic prediction model is established for traditional- and temperature-programmed alkaline thermal treatment (T-ATT and TP-ATT) of lignocellulose based on the content of three major components and their inherent H<sub>2</sub> production. The results indicate that the H<sub>2</sub> production from T-/TP-ATT of actual lignocellulose can be calculated by directly superimposing the H<sub>2</sub> production of microcrystalline cellulose, xylan and lignin, with prediction error < 5 %. This is attributed to the clear secondary reaction (methanation reaction of char) and extremely low tar content observed during reaction process. Moreover, variations in lignin composition constitute the fundamental cause of increased prediction errors in H<sub>2</sub> production for different feedstocks within same species. An innovative correction method utilizing the composition characteristics (C, H and O content) of lignin as critical parameters achieves optimal prediction of H<sub>2</sub> production for T-/TP-ATT process. The corrected prediction model can significantly reduce the prediction errors of H<sub>2</sub> production from unknown woody (1.1 % and 2.0 % for T-ATT and TP-ATT), herbaceous (5.0 % for T-ATT), vine (1.7 % and 3.9 % for T-ATT and TP-ATT), and hemp (4.8 % for T-ATT) feedstocks. The priority of actual lignocellulose for H<sub>2</sub> production is hemp > woody ≥ herbaceous > vine. This study will accelerate the practical application of T-/TP-ATT technology.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107585"},"PeriodicalIF":6.2,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880262","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 : 2025-12-28DOI: 10.1016/j.jaap.2025.107583
Xianglong Meng , Jingjing Li , Xiaoli Wang , Chuandong Li , Guizhong Deng , Xiaodong Tang
The co-hydrothermal liquefaction process of Chlorella and oil shale under subcritical water conditions was investigated. Reaction parameters such as temperature and residence time were optimized, with the highest oil yield obtained at 300 ℃ for 30 min. When the proportion of Chlorella was 50 % or more, a synergistic effect was observed, most notably at 75 %. The addition of metal oxide catalysts promoted hydrodeoxygenation, increasing hydrocarbon content, reducing oxygenated compounds, and improving both the hydrogen-to-carbon and oxygen-to-carbon ratios. The heating value of the oil products was within the typical range for biodiesel. Among all catalysts tested, CeO₂ showed the best performance by increasing hydrocarbon content by 24.73 %, raising the heating value to 36.09 MJ/kg, achieving 74.73 % energy recovery efficiency, and reducing the proportion of heavy oil and residue to 30.66 %.
{"title":"Regulation of oil yield and composition analysis from co-hydrothermal liquefaction of Chlorella and oil shale","authors":"Xianglong Meng , Jingjing Li , Xiaoli Wang , Chuandong Li , Guizhong Deng , Xiaodong Tang","doi":"10.1016/j.jaap.2025.107583","DOIUrl":"10.1016/j.jaap.2025.107583","url":null,"abstract":"<div><div>The co-hydrothermal liquefaction process of Chlorella and oil shale under subcritical water conditions was investigated. Reaction parameters such as temperature and residence time were optimized, with the highest oil yield obtained at 300 ℃ for 30 min. When the proportion of Chlorella was 50 % or more, a synergistic effect was observed, most notably at 75 %. The addition of metal oxide catalysts promoted hydrodeoxygenation, increasing hydrocarbon content, reducing oxygenated compounds, and improving both the hydrogen-to-carbon and oxygen-to-carbon ratios. The heating value of the oil products was within the typical range for biodiesel. Among all catalysts tested, CeO₂ showed the best performance by increasing hydrocarbon content by 24.73 %, raising the heating value to 36.09 MJ/kg, achieving 74.73 % energy recovery efficiency, and reducing the proportion of heavy oil and residue to 30.66 %.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107583"},"PeriodicalIF":6.2,"publicationDate":"2025-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880259","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 : 2025-12-28DOI: 10.1016/j.jaap.2025.107584
Wenqi Chen , Gang Wu , Yinhai Su , Enhui Sun , Huiyan Zhang
Straw pyrolysis yields wood vinegar and biochar, with wood vinegar holding significant agricultural potential due to growth-promoting components (acids, alcohols, ketones) but suffering from phenol-induced biotoxicity that restricts its application. To address this challenge, this study develops a binary activation strategy for the controllable preparation of straw-derived activated carbon (AC) using ZnCl2 and H3PO4 as activators, targeting efficient phenol removal from crude wood vinegar. Notably, the AC synthesized through binary impregnation activation using a 0.1 M mixed solution of ZnCl2 and H3PO4 exhibits an excellent pore structure, abundant oxygen-containing functional groups, and optimal adsorption performance, achieving a phenol removal efficiency of 82.8 % which is significantly higher than those of straw pyrolytic char 3.3 % and single-agent activation 71.8 % for ZnCl2 and 75.6 % for H3PO4. Furthermore, the targeted adsorption mechanism of harmful components was elucidated. The Langmuir isotherm model and pseudo-second-order kinetic model better fit the description of the targeted adsorption process of phenol on activated carbon, corresponding to a monolayer homogeneous adsorption process with abundant active sites. This work provides a sustainable approach for high-value utilization of straw waste, offering theoretical and technical insights into the controllable preparation of high-performance AC adsorbents and efficient refinement of crude wood vinegar.
秸秆热解产生木醋和生物炭，由于木醋具有促进生长的成分（酸、醇、酮），因此具有重要的农业潜力，但由于苯酚诱导的生物毒性，限制了其应用。为了解决这一挑战，本研究开发了一种二元活化策略，以ZnCl2和H3PO4为活化剂，可控制备秸秆衍生活性炭（AC），目的是高效去除粗木醋中的苯酚。值得注意的是，采用0.1 M ZnCl2和H3PO4混合溶液二元浸渍活化合成的活性炭具有优良的孔隙结构、丰富的含氧官能团和最佳的吸附性能，苯酚去除率为82.8 %，显著高于秸秆热解炭的3.3 %和单剂活化ZnCl2的71.8 %和H3PO4的75.6 %。进一步阐明了有害成分的靶向吸附机理。Langmuir等温线模型和拟二级动力学模型较好地拟合了苯酚在活性炭上的靶向吸附过程的描述，对应于一个具有丰富活性位点的单层均匀吸附过程。本研究为秸秆废弃物的高价值利用提供了一条可持续的途径，为高性能AC吸附剂的可控制备和粗木醋的高效精制提供了理论和技术见解。
{"title":"Controllable preparation of biomass-derived activated carbon for targeted adsorption of phenolic substances in crude wood vinegar","authors":"Wenqi Chen , Gang Wu , Yinhai Su , Enhui Sun , Huiyan Zhang","doi":"10.1016/j.jaap.2025.107584","DOIUrl":"10.1016/j.jaap.2025.107584","url":null,"abstract":"<div><div>Straw pyrolysis yields wood vinegar and biochar, with wood vinegar holding significant agricultural potential due to growth-promoting components (acids, alcohols, ketones) but suffering from phenol-induced biotoxicity that restricts its application. To address this challenge, this study develops a binary activation strategy for the controllable preparation of straw-derived activated carbon (AC) using ZnCl<sub>2</sub> and H<sub>3</sub>PO<sub>4</sub> as activators, targeting efficient phenol removal from crude wood vinegar. Notably, the AC synthesized through binary impregnation activation using a 0.1 M mixed solution of ZnCl<sub>2</sub> and H<sub>3</sub>PO<sub>4</sub> exhibits an excellent pore structure, abundant oxygen-containing functional groups, and optimal adsorption performance, achieving a phenol removal efficiency of 82.8 % which is significantly higher than those of straw pyrolytic char 3.3 % and single-agent activation 71.8 % for ZnCl<sub>2</sub> and 75.6 % for H<sub>3</sub>PO<sub>4</sub>. Furthermore, the targeted adsorption mechanism of harmful components was elucidated. The Langmuir isotherm model and pseudo-second-order kinetic model better fit the description of the targeted adsorption process of phenol on activated carbon, corresponding to a monolayer homogeneous adsorption process with abundant active sites. This work provides a sustainable approach for high-value utilization of straw waste, offering theoretical and technical insights into the controllable preparation of high-performance AC adsorbents and efficient refinement of crude wood vinegar.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107584"},"PeriodicalIF":6.2,"publicationDate":"2025-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880254","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 : 2025-12-27DOI: 10.1016/j.jaap.2025.107581
Mengchuan Jia , Sheng Su , Zhixiang Zhu , Wei Deng , Kai Xu , Long Jiang , Jun Xu , Yi Wang , Song Hu , Jun Xiang
As a promising clean combustion technology, coal/NH3 co-firing contributes significantly to “Dual Carbon” goals. Co-pyrolysis of coal/NH3 is a critical initial stage of co-combustion, profoundly influencing combustion characteristics and pollutant formation. A deep understanding of the influence of NH3 on coal pyrolysis process and the transformation of nitrogen-containing products is crucial for controlling subsequent combustion behavior and pollutant formation. In this study, synchrotron radiation photoionization mass spectrometry (SR-PIMS) experiments were combined with ReaxFF MD simulations to elucidate the influence of NH3 on coal pyrolysis products, char structure, and nitrogen migration mechanisms. SR-PIMS results demonstrated that NH3 generally suppressed the formation of hydrocarbons (m/z ≤ 104) and oxygenated compounds (m/z ≤ 118) in coal pyrolysis products, while promoting the generation of nitrogen-containing compounds (m/z ≤ 107). ReaxFF MD simulations revealed that radicals such as H· and NH2· derived from NH3 decomposition react with hydrocarbon radicals (C6H4, etc.) and oxygen-containing radicals (C5H9O2, etc.) produced by coal pyrolysis, stabilizing hydrocarbon and oxygen-containing radicals into stable compounds (C6H6, C5H10O2, etc.). This process suppresses their further reactions and decomposition, thereby inhibiting the evolution of hydrocarbons and oxygenates. Ultimate analysis and Raman spectroscopy of char also indicated that coal/NH3 co-pyrolysis char exhibits a higher H/C ratio, with NH3 inhibiting char aromatization and graphitization. Meanwhile, nitrogen-containing radicals derived from NH₃ embed into the carbon matrix, promoting the formation of nitrogen-containing compounds in char, and increasing nitrogen content in both volatiles and char, which was proved by SR-PIMS and ultimate analysis of char. The nitrogen migration mechanism revealed by ReaxFF MD simulations, consisting with XPS results, showed that during primary cracking, ammonia nitrogen primarily migrates via NH2 bonding to aliphatic chains to form aliphatic amines, which cyclize into N-5/N-6 species during secondary reactions. Temperature elevation accelerates the conversion from N-5 to N-6 with minor N-Q formation. Notably, NH3 directly promotes ring-opening of N-5 and N-6 in coal, converting them into nitrogen-containing long chains, promoting HCN and NH3 formation, causing a faster decline in coal nitrogen content. This process destabilizes derived aliphatic ring structures, which is unfavorable to char aromatization and graphitization. This work provides theoretical and data support for optimizing coal/NH3 co-firing technology.
{"title":"Effects of ammonia on coal pyrolysis products and nitrogen migration: Insights from SR-PIMS experiments combined with molecular dynamics simulations","authors":"Mengchuan Jia , Sheng Su , Zhixiang Zhu , Wei Deng , Kai Xu , Long Jiang , Jun Xu , Yi Wang , Song Hu , Jun Xiang","doi":"10.1016/j.jaap.2025.107581","DOIUrl":"10.1016/j.jaap.2025.107581","url":null,"abstract":"<div><div>As a promising clean combustion technology, coal/NH<sub>3</sub> co-firing contributes significantly to “Dual Carbon” goals. Co-pyrolysis of coal/NH<sub>3</sub> is a critical initial stage of co-combustion, profoundly influencing combustion characteristics and pollutant formation. A deep understanding of the influence of NH<sub>3</sub> on coal pyrolysis process and the transformation of nitrogen-containing products is crucial for controlling subsequent combustion behavior and pollutant formation. In this study, synchrotron radiation photoionization mass spectrometry (SR-PIMS) experiments were combined with ReaxFF MD simulations to elucidate the influence of NH<sub>3</sub> on coal pyrolysis products, char structure, and nitrogen migration mechanisms. SR-PIMS results demonstrated that NH<sub>3</sub> generally suppressed the formation of hydrocarbons (<em>m/z</em> ≤ 104) and oxygenated compounds (<em>m/z</em> ≤ 118) in coal pyrolysis products, while promoting the generation of nitrogen-containing compounds (<em>m/z</em> ≤ 107). ReaxFF MD simulations revealed that radicals such as H· and NH<sub>2</sub>· derived from NH<sub>3</sub> decomposition react with hydrocarbon radicals (C<sub>6</sub>H<sub>4</sub>, etc.) and oxygen-containing radicals (C<sub>5</sub>H<sub>9</sub>O<sub>2</sub>, etc.) produced by coal pyrolysis, stabilizing hydrocarbon and oxygen-containing radicals into stable compounds (C<sub>6</sub>H<sub>6</sub>, C<sub>5</sub>H<sub>10</sub>O<sub>2</sub>, etc.). This process suppresses their further reactions and decomposition, thereby inhibiting the evolution of hydrocarbons and oxygenates. Ultimate analysis and Raman spectroscopy of char also indicated that coal/NH<sub>3</sub> co-pyrolysis char exhibits a higher H/C ratio, with NH<sub>3</sub> inhibiting char aromatization and graphitization. Meanwhile, nitrogen-containing radicals derived from NH₃ embed into the carbon matrix, promoting the formation of nitrogen-containing compounds in char, and increasing nitrogen content in both volatiles and char, which was proved by SR-PIMS and ultimate analysis of char. The nitrogen migration mechanism revealed by ReaxFF MD simulations, consisting with XPS results, showed that during primary cracking, ammonia nitrogen primarily migrates via NH<sub>2</sub> bonding to aliphatic chains to form aliphatic amines, which cyclize into N-5/N-6 species during secondary reactions. Temperature elevation accelerates the conversion from N-5 to N-6 with minor N-Q formation. Notably, NH<sub>3</sub> directly promotes ring-opening of N-5 and N-6 in coal, converting them into nitrogen-containing long chains, promoting HCN and NH<sub>3</sub> formation, causing a faster decline in coal nitrogen content. This process destabilizes derived aliphatic ring structures, which is unfavorable to char aromatization and graphitization. This work provides theoretical and data support for optimizing coal/NH<sub>3</sub> co-firing technology.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107581"},"PeriodicalIF":6.2,"publicationDate":"2025-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880261","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 : 2025-12-27DOI: 10.1016/j.jaap.2025.107582
Hong Tian, Siying Liu, Kuan Ai, Zhangjun Huang, Zhen Zhou, Yanni Xuan
The growing energy crisis and environmental pollution stemming from conventional fossil fuel consumption have intensified the search for sustainable and renewable energy alternatives. Among the various strategies, hydrogen production via the steam reforming of waste plastics and biomass represents a highly promising pathway. This study investigates this process using wheat straw and polyethylene as feedstocks, with steam as the gasifying agent. A composite catalyst support was prepared from biochar (derived from wheat straw pyrolysis) and CaO, which was then impregnated with nickel (Ni) as the active metal. The research systematically evaluated the influence of several key parameters: Ni loading, the catalyst support blending ratio, the catalytic reforming temperature, the steam flow rate, and the biomass-to-plastic ratio.Results demonstrate that the synthesized Ni/CaO-C catalyst possesses a rich porous structure and a high concentration of oxygen-containing functional groups. The optimal conditions for hydrogen production were identified as follows: a Ni loading of 15 wt%, a pyrolysis temperature of 600℃, an equivalent catalyst support ratio (CaO to C of 5:5), a catalytic reforming temperature of 750℃, a steam flow rate of 0.2 g/min, and a balanced biomass-to-plastic ratio of 5:5. Under this optimized configuration, the process achieved a total gas yield of 101.95 mmol/g, a hydrogen yield of 80.54 mmol/g, a hydrogen concentration of 79.01 vol%, and an H₂/CO ratio of 5.82. This work provides an effective and novel approach for enhancing hydrogen generation from the steam conversion of waste materials.
{"title":"Catalytic steam reforming of biomass/plastics over Ni-Modified CaO-C catalysts for hydrogen production","authors":"Hong Tian, Siying Liu, Kuan Ai, Zhangjun Huang, Zhen Zhou, Yanni Xuan","doi":"10.1016/j.jaap.2025.107582","DOIUrl":"10.1016/j.jaap.2025.107582","url":null,"abstract":"<div><div>The growing energy crisis and environmental pollution stemming from conventional fossil fuel consumption have intensified the search for sustainable and renewable energy alternatives. Among the various strategies, hydrogen production via the steam reforming of waste plastics and biomass represents a highly promising pathway. This study investigates this process using wheat straw and polyethylene as feedstocks, with steam as the gasifying agent. A composite catalyst support was prepared from biochar (derived from wheat straw pyrolysis) and CaO, which was then impregnated with nickel (Ni) as the active metal. The research systematically evaluated the influence of several key parameters: Ni loading, the catalyst support blending ratio, the catalytic reforming temperature, the steam flow rate, and the biomass-to-plastic ratio.Results demonstrate that the synthesized Ni/CaO-C catalyst possesses a rich porous structure and a high concentration of oxygen-containing functional groups. The optimal conditions for hydrogen production were identified as follows: a Ni loading of 15 wt%, a pyrolysis temperature of 600℃, an equivalent catalyst support ratio (CaO to C of 5:5), a catalytic reforming temperature of 750℃, a steam flow rate of 0.2 g/min, and a balanced biomass-to-plastic ratio of 5:5. Under this optimized configuration, the process achieved a total gas yield of 101.95 mmol/g, a hydrogen yield of 80.54 mmol/g, a hydrogen concentration of 79.01 vol%, and an H₂/CO ratio of 5.82. This work provides an effective and novel approach for enhancing hydrogen generation from the steam conversion of waste materials.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107582"},"PeriodicalIF":6.2,"publicationDate":"2025-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145920678","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 : 2025-12-26DOI: 10.1016/j.jaap.2025.107565
Sihai Ni, Yi Shao, Jingjing Wang, Ning Deng, Liangyuan Jia
The H2O2-activated carbon (OAC) was used for the first time for ex-situ catalytic pyrolysis of low-density polyethylene (LDPE) to produce jet fuel-range hydrocarbons. Controlled H2O2 treatment introduces hydroxy groups to optimize surface acidity and pore structure, thereby balancing C-C cleavage and alkane-to-aromatic conversion. The produced jet fuel-range hydrocarbons (C8-C16) comprise approximately 80 % linear/cyclic alkanes and 20 % mono-aromatics, meeting aviation fuel requirement. Meanwhile, under optimal hydrocarbon distribution conditions, 90.90 wt% liquid hydrocarbon yield with 93.75 % C8-C16 selectivity was achieved. Besides, temperature-controlled experiments demonstrate tunable product distribution across diesel, jet fuel, and gasoline ranges can be obtained, highlighting the process flexibility. In addition, the catalyst maintains high C8-C16 selectivity (> 80 %) after 10 reaction cycles. Mechanistically, appropriate surface -OH groups promote alkane formation while suppressing excessive aromatization, enabling the high-yield production of target hydrocarbons. OACs, as low-cost, easily prepared, highly efficient, and stable catalysts, enable economical jet fuel production from the catalytic pyrolysis of waste plastics.
{"title":"Ex-situ catalytic pyrolysis of low-density polyethylene for jet-fuel range hydrocarbons production over H2O2-modified activated carbon","authors":"Sihai Ni, Yi Shao, Jingjing Wang, Ning Deng, Liangyuan Jia","doi":"10.1016/j.jaap.2025.107565","DOIUrl":"10.1016/j.jaap.2025.107565","url":null,"abstract":"<div><div>The H<sub>2</sub>O<sub>2</sub>-activated carbon (OAC) was used for the first time for ex-situ catalytic pyrolysis of low-density polyethylene (LDPE) to produce jet fuel-range hydrocarbons. Controlled H<sub>2</sub>O<sub>2</sub> treatment introduces hydroxy groups to optimize surface acidity and pore structure, thereby balancing C-C cleavage and alkane-to-aromatic conversion. The produced jet fuel-range hydrocarbons (C8-C16) comprise approximately 80 % linear/cyclic alkanes and 20 % mono-aromatics, meeting aviation fuel requirement. Meanwhile, under optimal hydrocarbon distribution conditions, 90.90 wt% liquid hydrocarbon yield with 93.75 % C8-C16 selectivity was achieved. Besides, temperature-controlled experiments demonstrate tunable product distribution across diesel, jet fuel, and gasoline ranges can be obtained, highlighting the process flexibility. In addition, the catalyst maintains high C8-C16 selectivity (> 80 %) after 10 reaction cycles. Mechanistically, appropriate surface -OH groups promote alkane formation while suppressing excessive aromatization, enabling the high-yield production of target hydrocarbons. OACs, as low-cost, easily prepared, highly efficient, and stable catalysts, enable economical jet fuel production from the catalytic pyrolysis of waste plastics.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107565"},"PeriodicalIF":6.2,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880257","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}
Polycarbonate (PC) exhibits flammability that is prone to fire hazards during production and application, making its combustion process crucial for fire prevention and personnel protection. Reactive forcefield simulations were utilized to reveal the mechanism governing PC combustion under variable oxygen concentrations (oxygen-lean, stoichiometry, and oxygen-rich) at the microscopic level. The effects of temperature and oxygen concentration on the combustion process and the distribution of the main products of PC were investigated. The final combustion products are mainly H2O, CO2, and CO. The generation of CO2 includes the oxidation or dehydrogenation reaction of carboxylic acid. The formation of CO mainly depends on the breaking of C-C bonds in small molecules, such as ·C2O3 and ·C2O2. The generated mechanism of H2O mainly relies on the ·OH capturing the ·H from other groups. During the simulation, the PC chains undergo pyrolysis followed by combustion reactions, and the process is affected by oxygen concentration. The initial reactions of PC chains are mainly pyrolysis reactions under oxygen-lean conditions, and combustion reactions dominate under stoichiometric and oxygen-rich conditions. As the temperature and oxygen concentration rose, they significantly accelerated the combustion reaction rate of PC and also played a key role in regulating the product distribution. They were beneficial to the decomposition of macromolecules (C40+) into intermediate products (C14–40 and C5–13) and finally into small molecular gas products (C0–4). Rising oxygen concentration also promoted the conversion process from C-C bonds to C-O bonds. The findings could provide some guidance to selectively regulate the combustion process of the PC composites.
{"title":"Unraveling the oxygen-dependent combustion mechanisms of polycarbonate by molecular dynamic simulation","authors":"Zheqing Sang, Yongqing Wan, Ting Zhang, Mengxi Yuan, Mengyan Zhao, Zhuiyue Guo, Qingqing Zheng, Yaxing Li, Yanhua Lan","doi":"10.1016/j.jaap.2025.107578","DOIUrl":"10.1016/j.jaap.2025.107578","url":null,"abstract":"<div><div>Polycarbonate (PC) exhibits flammability that is prone to fire hazards during production and application, making its combustion process crucial for fire prevention and personnel protection. Reactive forcefield simulations were utilized to reveal the mechanism governing PC combustion under variable oxygen concentrations (oxygen-lean, stoichiometry, and oxygen-rich) at the microscopic level. The effects of temperature and oxygen concentration on the combustion process and the distribution of the main products of PC were investigated. The final combustion products are mainly H<sub>2</sub>O, CO<sub>2</sub>, and CO. The generation of CO<sub>2</sub> includes the oxidation or dehydrogenation reaction of carboxylic acid. The formation of CO mainly depends on the breaking of C-C bonds in small molecules, such as ·C<sub>2</sub>O<sub>3</sub> and ·C<sub>2</sub>O<sub>2</sub>. The generated mechanism of H<sub>2</sub>O mainly relies on the ·OH capturing the ·H from other groups. During the simulation, the PC chains undergo pyrolysis followed by combustion reactions, and the process is affected by oxygen concentration. The initial reactions of PC chains are mainly pyrolysis reactions under oxygen-lean conditions, and combustion reactions dominate under stoichiometric and oxygen-rich conditions. As the temperature and oxygen concentration rose, they significantly accelerated the combustion reaction rate of PC and also played a key role in regulating the product distribution. They were beneficial to the decomposition of macromolecules (C<sub>40+</sub>) into intermediate products (C<sub>14–40</sub> and C<sub>5–13</sub>) and finally into small molecular gas products (C<sub>0–4</sub>). Rising oxygen concentration also promoted the conversion process from C-C bonds to C-O bonds. The findings could provide some guidance to selectively regulate the combustion process of the PC composites.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107578"},"PeriodicalIF":6.2,"publicationDate":"2025-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880256","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号