FUEL
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2026
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IF 7.8
Zeyu Wu,Zhen Yang,Xinyue Zhao,Xi Gao,Yuan Xue,Mo Zheng,Liangyuan Jia,Zhongyue Zhou
Catalytic co-pyrolysis of lignin and hydrogen rich plastics with zeolite can potentially mitigate the problems including low conversion and severe coking with lignin. However, controversial conclusions still exist regarding the synergistic effects and cross-reaction pathways between the two feedstocks, resulting from complex product composition and limited testing methods. To clarify the aforementioned problems, the current study investigated the catalytic co-pyrolysis of model compounds from lignin (guaiacol) and polyethylene with HZSM-5 by using in-situ sampling and online vacuum ultraviolet photoionization mass spectrometry (VUV-PIMS). Specifically, C6 hydrocarbons (n-hexane, hexene, and hexadiene) with different unsaturation degrees were chosen to understand the role of plastic-derived volatiles in co-pyrolysis. Pyrolysis of individual feedstock showed that the increase of double bonds in C6 hydrocarbons could enhance the production of aromatic hydrocarbons, while the conversion of guaiacol to aromatic hydrocarbons occurred following the pathways as: guaiacol→catechol→phenol&cresol→BTX (benzene, toluene, and xylene). Analyzing the evolution of major intermediates and products from co-pyrolysis showed that hydrogen transfer from C6 hydrocarbon to guaiacol significantly enhanced the conversion of catechol to phenol/cresol and subsequent hydrodeoxygenation to BTX. Hexadiene showed the strongest synergistic effects with guaiacol, as abundant hydrogen was generated from aromatization reaction and then transferred. Fitting the evolution curves with 1st order catalyst deactivation kinetics model indicated that the decay factors calculated based on the yield changes of BTX and typical phenolic products were significantly lower with co-pyrolysis. The synergistic effects to mitigate catalyst deactivation and coke formation were further confirmed by characterizations of spent catalysts, catalytic coke and coke precursors, strength of which followed the order as hexadiene (16.7%) > hexene (13.0%) > n-hexane (8.5%). These experimental observations were further corroborated by ReaxFF MD simulations, which provide complementary evidence for hydrogen-transfer interactions.
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产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2026
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IF 6.7
Zheng-Zhi Zhang,Zhu-Fei Yang,Ya-Sen Wu,Zhan-Ku Li,Jing-Chong Yan,Wei-Dong Zhang,Zhi-Ping Lei,Shi-Biao Ren,Zhi-Cai Wang,Heng-Fu Shui
The unclear migration mechanism of organic sulfur during coal pyrolysis limits molecular-level understanding, hindering targeted desulfurization and clean utilization of high-sulfur coal. In this study, a "structural simplification" strategy was proposed, in which the thermal dissolution soluble fraction (TDSF) from Duizhen high-sulfur coking coal (DHSC) was employed as the research subject. This TDSF is characterized by its structural homogeneity and ash-free nature, thereby eliminating the interference caused by structural heterogeneity and ash. By combining TG-MS and ReaxFF-MD simulations, the abundant aliphatic structures in TDSF generate a strong "self-hydrogen supply" effect during the pyrolysis process. At 2800 K, the number of C-H bond cleavages in the DHSC/N 2 system is 167, whereas in the TDSF/N 2 system, it reaches as high as 258. The co-hydrogenation experiments of TDSF and DHSC with phenanthrene demonstrated that the hydrogen-donating capacity of TDSF was 1.64 times that of DHSC. The generated active hydrogen radicals selectively attack the C-S bonds in thiophene and sulfoxide, prompting a large amount of sulfur to migrate to the gas and liquid phases. The pyrolysis experiments showed that the sulfur removal rate of TSDF (37.39%) during pyrolysis was significantly higher than that of DHSC (30.08%). It was demonstrated that the desulfurization performance of DHSC can be further enhanced by the use of a hydrogen atmosphere and elevated pyrolysis temperatures. Based on these molecular-level insights, precise desulfurization strategies for high-sulfur coal pyrolysis can be formulated.
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DOI
高影响因子
COMBUSTION AND FLAME
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2024
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IF 5.8
Wenlong Dong,Run Hong,Yuhang Yang,Dongyang Wang,Bingbing Qiu,Huaqiang Chu
The soot formation of n- heptane/iso-octane doped 2,5-dimethylfuran (DMF) with different ratios was experimentally investigated through laminar diffusion flame and numerically simulated by using the pyrolysis simulations method of reactive force field molecular dynamics (ReaxFF MD). The results showed that the laminar diffusion flame height of n- heptane/iso-octane increased with increasing DMF doping ratio. At a consistent sampling height, the primary soot particle sampling numbers collected were first decreasing and then increasing, and the size of the primary soot particle was first increasing and then decreasing accompanied by the DMF doping ratio increasing. Furthermore, the transmission electron microscope (TEM) analysis provided that DMF initially inhibited and subsequently promoted the primary soot particle growth in the n- heptane/iso-octane flame. The core-shell ratio increased and then decreased with the increase of the DMF doping ratio, which indicated that the maturity of soot decreased and then increased. In n- heptane/iso-octane doped with DMF ReaxFF MD pyrolysis simulation, it was divided into three stages 0–0.5 ns (the first stage), 0.5–3 ns (the second stage), and 3–4.5 ns (the third stage). Fuel decomposed in the first stage and reacted violently in the second stage. The soot precursors continued to react, molecule size kept to increase, and the polycyclic aromatic hydrocarbons (PAHs) continued to grow. In the third stage, the carbon number of the largest molecules were slowly increasing, and the development of soot entered mature stage, where the H/C ratio was slowly decreasing. Through ReaxFF MD simulations, it was found that the maturity of soot exhibited decreasing and then increasing trend with the increase of DMF doping ratio. The graphene-like structures were mainly concentrated around the H/C ratio of 0.297 region.
研究领域:
化学工程
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燃烧科学
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材料科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2026
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IF 12.5
Wei Feng,Xiaodong Chen,Jin Bai,Mo Zheng,Jinjun Guo,Congbin Jiang,Xianxian Zhang,Zongqing Bai,Wen Li
Integrating ReaxFF MD with TGA and in-situ Py-TOF-MS reveals synergistic mechanisms in co-pyrolysis of coal with HDPE, PP, and PS. • PP promotes C 5 -C 6 high-calorific gases, while PS enhances aromatics by cross-linking pathways. • PP promotes C C and C H cleavage while PS inhibits C O breaking and weakly promotes C H cleavage. • Coal/HDPE and coal/PP co-pyrolysis drive PAHs formation via Diels-Alder, alkylation, and aromatization reactions. • The polymer type critically determines the nature of the dominant reactive intermediates. Co -pyrolysis of low-rank coal and waste polymers offers a promising approach for plastic valorization while enhancing coal utilization and oil quality. In this work, the polymer types on the synergistic mechanism governing the co -pyrolysis of Zhundong low-rank coal and three typical polymers of HDPE, PP and PS were systematically investigated by integrating ReaxFF MD simulation with experiments of TG and in-situ Py-TOF-MS. It is observed that the temperatures of maximum weight loss ( T max ) follow the order of HDPE > PP > PS, consistently reproduced across three methods. PP addition promotes C 5 -C 6 high-caloric-value gases via long-chain cleavage while inhibiting the MAHs production. In contrast, PS facilitates phenolic hydroxyl removal from coal, promoting aromatic products. PS preferentially enhances light tar yield from 17.81% to 22.14%, whereas HDPE suppresses heavy tar yields from 39.90% to 35.56%. The ReaxFF MD simulation results further demonstrate the underlying molecular-scale mechanisms that are hardly accessible by experiments. HDPE and PP inhibit C O bond formation while promoting C H bond breaking during the co-pyrolysis. PP exhibits the strongest promotion of C-C/ C H cleavage, whereas PS shows the weakest effect on C H dissociation. During coal/HDPE and coal/PP co-pyrolysis, the formation of PAHs is promoted through Diels-Alder, alkylation and aromatization reactions. For coal/PS, the phenyl-alkyl radicals from PS combine with light tar, heavy tar, and char intermediates from coal to form cross-linked intermediates, facilitating cleavage of α -C ar -C al , β -C al -C al , and C ar -O bonds toward aromatics. The integrated strategy provides a comprehensive perspective for understanding co-pyrolysis mechanisms in other solid fuels and waste treatments. Download: Download high-res image (87KB) Download: Download full-size image
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DOI
高影响因子
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