Journal of Analytical and Applied Pyrolysis最新文献

{"title":"Fast pyrolysis behavior of paraffinic and intermediate based residues over acid-base composite catalysts at the molecular level","authors":"Bohao Li ,&nbsp;Guangyao Wang ,&nbsp;Tong Su ,&nbsp;Ronglong Guo ,&nbsp;Chunxiao Gao ,&nbsp;Jinhong Zhang ,&nbsp;Yuanyu Tian","doi":"10.1016/j.jaap.2026.107617","DOIUrl":"10.1016/j.jaap.2026.107617","url":null,"abstract":"<div><div>High-temperature fast catalytic pyrolysis is an efficient method for converting heavy oils into light olefins and BTX. In this study, the process was applied to two atmospheric residues: the paraffinic based DQ-AR and the intermediate based NP-AR. Each residue was fractionated into eight group fractions and analyzed using Py-GC-MS/FID. Average molecular structural parameters were calculated using the modified Brown-Ladner method, and their correlations with product distributions were evaluated via Spearman correlation analysis. The optimal catalyst composition (70 wt% ZSM-5 and 30 wt% CaAl) achieved the highest light olefin yield. Among the fractions, saturates and light aromatics exhibited the highest olefin selectivity, whereas asphaltenes exhibited the lowest. DQ-AR, characterized by a higher paraffinic carbon fraction (<em>f</em>_<em>P</em>), longer average length of aliphatic chains (<em>L</em>), and a higher hydrogen-to-carbon ratio (<em>N</em>_<em>H</em><em>/N</em>_<em>C</em>), demonstrated superior selectivity toward olefins and BTX. In contrast, NP-AR, with greater aromatic and naphthenic ring number (<em>R</em>_<em>A</em>, <em>R</em>_<em>N</em>) and a higher condensation degree of aromatic rings (<em>H</em>_<em>AU</em><em>/C</em>_<em>A</em>), favored aromatization and coke formation. By integrating average structural parameters with product selectivities, structure-selectivity heatmaps were constructed across various catalytic systems. This enabled the establishment of a quantitative structure-reactivity framework that provides molecular-level insights into the catalytic upgrading of heavy oils.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"195 ","pages":"Article 107617"},"PeriodicalIF":6.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975805","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}

{"title":"A review on oxidative pyrolysis and oxidative torrefaction: Mechanisms, products, kinetics and future directions","authors":"Syazmi Zul Arif Hakimi Saadon ,&nbsp;Nurul Hidayah Abdullah ,&nbsp;David Onoja Patrick ,&nbsp;Tuan Muhammad Isma Hafizzuddin Bin Tuan Ismail ,&nbsp;Noridah Binti Osman","doi":"10.1016/j.jaap.2026.107609","DOIUrl":"10.1016/j.jaap.2026.107609","url":null,"abstract":"<div><div>Oxidative thermochemical processes, such as oxidative torrefaction and oxidative pyrolysis, differ from conventional inert processes by incorporating oxygen, which enhances reaction rates, reduces processing times, and modifies product composition. This presence of oxygen allows for higher energy efficiency and the production of bio-products with unique chemical characteristics, making these processes appealing for renewable energy and sustainable material applications. Oxidative torrefaction and pyrolysis have thus emerged as promising biomass conversion technologies, producing valuable biochar, bio-oil, and syngas with enhanced energy density and stability. However, they also present challenges, such as the need for precise oxygen control to prevent excessive combustion, and issues related to by-product management that may impact product quality and environmental sustainability. This review examines the mechanistic pathways of oxidative thermochemical reactions, distinguishing the endothermic and exothermic steps, and highlights yields from oxidative and inert conditions, including the biochar, bio-oil, and syngas. By synthesizing findings across the biomass feedstocks, the paper also compares kinetic modelling approaches with reported activation energy and pre-exponential factors. Additionally, the challenges and opportunities inherent in both oxidative torrefaction and oxidative pyrolysis are assessed, providing a nuanced understanding of the current state and future potential of these technologies. Despite the promise of oxidative pyrolysis and torrefaction, challenges persist. This review critically synthesizes parametric studies on oxidative torrefaction and oxidative pyrolysis, highlighting inconsistencies, governing parameters, and unresolved challenges affecting product yields, properties, and reaction mechanisms. The aim is to serve as a pivotal resource for researchers and industry professionals seeking to harness these transformative processes for sustainable biomass utilization, ultimately contributing to the advancement of renewable energy and carbon management strategies. With a detailed exploration of existing research and emerging trends, the review offers comprehensive insights into the future directions for both energy and carbon management fields.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"195 ","pages":"Article 107609"},"PeriodicalIF":6.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024794","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}

{"title":"Rich hydrogen syngas production from microwave-assisted catalytic pyrolysis of polypropylene plastic particles","authors":"Zhihong Liu ,&nbsp;Tao Liu ,&nbsp;Wenke Zhao ,&nbsp;Yaning Zhang ,&nbsp;Wei Liu","doi":"10.1016/j.jaap.2026.107628","DOIUrl":"10.1016/j.jaap.2026.107628","url":null,"abstract":"<div><div>Plastics bring convenience to human life, but also cause serious environmental pollution. The recycling of waste plastics is an effective way to solve the current energy shortage and environmental pollution. Microwave is widely used in the field of waste plastic pyrolysis due to its high heating rate, minimal heat loss, and less pollution in the heating process. In this study, cobalt oxide was used as microwave absorber and catalyst, the hydrogen production characteristics of microwave-assisted pyrolysis of polypropylene (PP) plastic particles were investigated. The results showed that microwave-assisted pyrolysis results in more hydrogen production. The hydrogen volume fraction, hydrogen yield, and hydrogen efficiency all increased continuously with increasing reaction temperature, reaching 68.2 vol%, 28.8 mmol/g_PP, and 38.4 % at 850 °C, respectively. With the increase of microwave power and Co₃O₄/PP mass ratio, the hydrogen volume fraction, hydrogen yield and hydrogen efficiency increased first and then decreased, and they reached the highest value when the microwave power was 500 W and the Co₃O₄/PP mass ratio was 1 at 850 °C. When the microwave power was greater than 500 W or the Co₃O₄/PP mass ratio was greater than 1, the heating rate of the polypropylene plastic particles was too high, reducing the selectivity of the Co₃O₄ for hydrogen production, resulting in lower hydrogen production. The role of Co₃O₄ in microwave-assisted pyrolysis of plastics is manifested in two aspects. On the one hand, its magnetic loss generates a large amount of thermal energy, providing a high-temperature environment for the pyrolysis of plastics; on the other hand, it adsorbs small molecules of gaseous hydrocarbons and promotes the polarization fracture of the C-H bond to produce hydrogen.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"195 ","pages":"Article 107628"},"PeriodicalIF":6.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024789","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}

{"title":"Enhancing bio-oil yield and quality from palm kernel shells via co-pyrolysis with palm fresh fruit in a double auger reactor","authors":"Nathawat Unsomsri ,&nbsp;Natthapol Unsomsri ,&nbsp;Sommas Kaewluan ,&nbsp;Sittinun Tawkaew ,&nbsp;Songkran Wiriyasart","doi":"10.1016/j.jaap.2026.107632","DOIUrl":"10.1016/j.jaap.2026.107632","url":null,"abstract":"<div><div>This study explores the co-pyrolysis of palm kernel shell (PKS) and palm fresh fruit (PFF) residues using a double-auger reactor operated at 550 °C to evaluate the impact of feedstock blending on bio-oil yield, composition, physicochemical properties, and carbon distribution. Three blend ratios, PKS:PFF at 100:0, 75:25, and 50:50, were tested to optimize product distribution. Bio-oil yield markedly increased from 5.7 % (pure PKS) to 17.4 % at a 50:50 blend, driven by PFF’s high volatile and lipid content. Distillation showed the diesel-range fraction rising from 12 % to 33 %, while the higher heating value improved slightly from 38.83 MJ kg⁻¹ to 41.00 MJ kg⁻¹. GC-MS analysis revealed hydrocarbon- and phenolic-rich bio-oils, with phenol dominant. Mechanistically, PFFs’ in-situ hydrogen donation fostered deoxygenation and demethoxylation reactions, enhancing fuel quality. Increasing PFF content boosted diesel-range alkanes and alkenes, reduced oxygenated compounds, and improved energy density. Physicochemical properties also notably improved, including reductions in specific gravity, kinematic viscosity, and total acid number. Elemental analysis confirmed higher carbon and hydrogen, and a notable oxygen reduction (13.47 % to 11.36 %) in the bio-oil. These results indicate PKS-PFF co-pyrolysis is a promising approach for upgrading palm biomass waste into liquid fuels with improved yield and composition, valorizing industrial residues. Future work should include engine testing of distilled fractions for performance, emissions, and long-term fuel stability.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"195 ","pages":"Article 107632"},"PeriodicalIF":6.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024349","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}

{"title":"From waste to watts: CoQDs on biochar as efficient catalysts for biomass-to-hydrogen conversion","authors":"Saimatun Nisa,&nbsp;Gaurav A. Bhaduri","doi":"10.1016/j.jaap.2025.107495","DOIUrl":"10.1016/j.jaap.2025.107495","url":null,"abstract":"<div><div>This study presents the design and application of cobalt quantum dots (CoQDs) supported on walnut shell-derived biochar as efficient catalysts for microwave-assisted biomass pyrolysis. Two catalyst formulations (Co-0.1 M and Co-0.5 M), with average CoQD sizes of 2.45 nm and 3.90 nm, respectively, were synthesized via an energy-efficient in situ microwave-assisted method. Comprehensive characterization (FTIR, Raman, XPS, XRD, SAED, SEM-EDX, and TEM) confirmed successful CoQD dispersion on the carbonaceous matrix. Thermogravimetric analysis coupled with iso-conversional models (FWO, KAS, ST) revealed a substantial reduction in activation energy—from 229.16 kJ/mol (non-catalytic) to 200.64 kJ/mol and 146.42 kJ/mol for Co-0.1 M and Co-0.5 M, respectively. Kinetic compensation effects and mechanistic analyses using the Achar and Criado master plots indicated mixed nucleation and diffusion-controlled degradation. Catalytic pyrolysis at 600 °C significantly enhanced pyro-gas yield (from 52 % to 75 %) and increased hydrogen content in the gas phase (from 5 % to 25 %). GC-MS and GC analyses revealed enhanced formation of phenolic compounds and gasoline-range hydrocarbons in the bio-oil. These results underscore the potential of CoQDs-functionalized biochar as a cost-effective catalyst for selective, energy-efficient biomass valorization via microwave pyrolysis.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107495"},"PeriodicalIF":6.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682699","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}

{"title":"Phase separation with corresponding compositional changes in bio-oil from co-pyrolysis of extractive-rich waste biomass","authors":"Mukul Agrawal ,&nbsp;Sanjeev Yadav ,&nbsp;Pravakar Mohanty","doi":"10.1016/j.jaap.2025.107491","DOIUrl":"10.1016/j.jaap.2025.107491","url":null,"abstract":"<div><div>The present work investigated the phenomenon of phase separation in bio-oil obtained by the co-pyrolysis of cotton stalk (CS) and cooked food waste (CFW). The experiments were conducted at three different carrier gas (N₂) flow rates (5, 7.5, and 10 LPM) and for their different mixing ratios in mixed feed to fast pyrolysis. At a low flow rate of 5LPM, the low mixing ratios of CFW in mixed feed (10 %, 25 %, and 50 %) produced the single-phase bio-oil and higher mixing ratios (&gt;50 %) produced the two-phase bio-oil. However, at the higher flow rates (7.5 and 10 LPM), even a mixing ratio of 50 % CFW in mixed feed with CS produced a two-phase bio-oil. The two-phase bio-oil contained a water-rich phase, named as an aqueous phase (AP), and an oil phase (OP). A single-phase bio-oil mainly contained oxygenated organic compounds (OAC), furans, carbonyl compounds, and fatty acid alkyl esters (FAAEs) in varying proportions. However, in two-phase bio-oil, the AP contained the first three compounds in a large fraction, but additionally, it contained nitrogenated compounds, originating from the protein present in CFW. However, the oil phase was excessively enriched with the FAAEs (up to 88 %) formed by the thermal decomposition of lipids present in CFW and CS, along with minor compounds like non-alkyl esters, alcohols, and other carbonyl compounds. Finally, a reaction mechanism was proposed for dual-phase formation as well as for compositional changes in bio-oil in each phase.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107491"},"PeriodicalIF":6.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682700","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}

{"title":"Effects of pretreatment on aromatic production from catalytic pyrolysis of soy sauce residue for organic liquid hydrogen carriers","authors":"Qi Niu ,&nbsp;Peng-yu Xing ,&nbsp;Lei Yi ,&nbsp;Ding-wang Qiao ,&nbsp;Zhi-mo Fang ,&nbsp;Ze-jun Luo ,&nbsp;Shu Zheng ,&nbsp;Kai Li ,&nbsp;Xiang-yu Zhang ,&nbsp;Qiang Lu","doi":"10.1016/j.jaap.2026.107599","DOIUrl":"10.1016/j.jaap.2026.107599","url":null,"abstract":"<div><div>Aromatic hydrocarbons (AHs) represent important organic liquid hydrogen carriers due to their abundant unsaturated bonds. As the only renewable carbon source, biomass can be directionally converted into AHs through catalytic pyrolysis, offering a low-carbon and environmentally friendly approach. Soy sauce residue (SSR), a fermentation by-product with high volatility and thermal decomposability, shows unique advantages for catalytic pyrolysis into AHs. However, SSR contains high mass fraction of salts and ash, which adversely affect the selective production of AHs. In this study, high-salt SSR was selected as the raw material and pretreated with deionized water and dilute HCl solution to remove salts and ash. The effects of washing pretreatment on the intrinsic physicochemical properties, pyrolysis kinetics, product distribution, and hydrogen storage performance of the resulting AHs were investigated. The pretreatment led to a significant increase in cellulose and lignin content and a reduction in hemicellulose. Moreover, washing pretreatment effectively removed ash from SSR, reduced the catalytic effects of inherent ash, and enhanced both the yield of AHs and their hydrogen storage capacity. Compared to water washing, acid washing pretreatment proved more effective, with higher temperatures favoring the removal of inorganic matter. At a pretreatment temperature of 80℃, acid washing removed 90.57 % of salts and 83.25 % of ash. Under optimal pyrolysis conditions (650℃, HZSM-5/SSR ratio of 12), the AH yields increased from 16.10 wt% (untreated SSR) to 24.82 wt% (HCl-treated SSR), and the hydrogen storage capacity of AHs also increased from 11.37 g/kg (untreated SSR) to 17.09 g/kg (HCl-treated SSR).</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107599"},"PeriodicalIF":6.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921189","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}

{"title":"Nutrient conversion during the fertilization of rice straw: Pyrolysis versus fermentation","authors":"Lide Liu ,&nbsp;Qing Luo ,&nbsp;Yujiao Wen ,&nbsp;Shangzhi Wei ,&nbsp;Shun Zhang ,&nbsp;Nan Sun ,&nbsp;Rui Qin ,&nbsp;Wenzhi Yang ,&nbsp;Zuoxiang Xiang ,&nbsp;Longxing Hu ,&nbsp;Zhi Zhou ,&nbsp;Nan Zhou","doi":"10.1016/j.jaap.2025.107556","DOIUrl":"10.1016/j.jaap.2025.107556","url":null,"abstract":"<div><div>Pyrolysis and fermentation are the main ways of utilization of straw waste. However, existing studies lack information on the differences in nutrient conversion between the two approaches. This study compared these methods using rice straw, analyzing element retention and product properties. The results showed that fermentation enhanced nutrient retention, doubling total nitrogen (TN) to 18.56 g·kg⁻¹ and available nitrogen (AN) to 953.13 mg·kg⁻¹, up from 9.91 g·kg⁻¹ and 479.15 mg·kg⁻¹ in raw straw. Thermochemical transformation is conducive to the accumulation of total phosphorus (TP) and total potassium (TK) in biomass. Pyrolysis at 550 C for 2 h increased total TP and TK to 3.11 g·kg⁻¹ and 67.97 g·kg⁻¹, respectively, from 0.96 g·kg⁻¹ and 14.87 g·kg⁻¹ in RS. In the pyrolysis range from 350 to 550 C, TP and TK in thermochemical transformation products increased with the increase of pyrolysis temperature. In the soil cultivation experiment, straw biochar can promote the plant height and root length of rice seedlings under the three concentrations. The above results are of great significance for the efficient utilization and sustainable development of straw waste.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107556"},"PeriodicalIF":6.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836942","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}

{"title":"Integrating kinetics, thermodynamics, and compensation effects of cellulose conversion with bimetallic oxygen carriers","authors":"Zhitong Yao ,&nbsp;Jiayao Tong ,&nbsp;Chongxin Huang ,&nbsp;Sachin Kumar ,&nbsp;Shaodan Xu ,&nbsp;Huanxuan Li ,&nbsp;Haoqi Wang ,&nbsp;Yang Chen ,&nbsp;Nebojša Manić ,&nbsp;Ljiljana Medic Pejic ,&nbsp;Jie Liu ,&nbsp;Wei Qi","doi":"10.1016/j.jaap.2025.107570","DOIUrl":"10.1016/j.jaap.2025.107570","url":null,"abstract":"<div><div>The chemical looping pyrolysis (CLP) of cellulose over NiFe₂O₄ was probed to elucidate the kinetic and thermodynamic mechanisms and compensation effects. The incorporation of oxygen carrier NiFe₂O₄ induced additional decomposition peaks, indicative of altered reaction pathways. Thermogravimetric/Fourier transform infrared spectroscopy (TG-FTIR) and thermogravimetry/gas chromatography-mass spectrometry (TG-GC/MS) analyses revealed a shift in major products from <span>D</span>-glucose in cellulose to furan derivatives and acetic acid in the cellulose/NiFe₂O₄ blend, demonstrating catalytic promotion of secondary conversion pathways. Model-free kinetic analyses showed a decrease in the apparent activation energies from 147.90 kJ mol⁻¹ to 93.99 kJ mol⁻¹ . Master-plots analysis indicated the dominant R3 reaction mechanism, with deviations toward the A2 model at α&gt; 0.60. Thermodynamic parameters revealed a decrease in the enthalpy change from 142.66 kJ mol⁻¹ to 88.50 kJ mol⁻¹ and negative entropy change (−0.088 kJ mol⁻¹K⁻¹) for the blend, while Gibbs free energy change remained nearly constant (∼143.5 kJ mol⁻¹). Kinetic and enthalpy–entropy compensation effects were confirmed, with isokinetic temperatures of 596.50 K and 880.07 K for cellulose and the blend, and corresponding free energy of compensation of 143.81 and 140.05 kJ mol⁻¹ . These findings demonstrated that NiFe₂O₄ lowered energy barriers, reorganized transition states, and enhanced cellulose reactivity, providing a quantitative basis for optimizing CLP processes.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107570"},"PeriodicalIF":6.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837372","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}

{"title":"Effects of ammonia on coal pyrolysis products and nitrogen migration: Insights from SR-PIMS experiments combined with molecular dynamics simulations","authors":"Mengchuan Jia ,&nbsp;Sheng Su ,&nbsp;Zhixiang Zhu ,&nbsp;Wei Deng ,&nbsp;Kai Xu ,&nbsp;Long Jiang ,&nbsp;Jun Xu ,&nbsp;Yi Wang ,&nbsp;Song Hu ,&nbsp;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/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 (<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 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.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"194 ","pages":"Article 107581"},"PeriodicalIF":6.2,"publicationDate":"2026-03-01","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}