CEMENT AND CONCRETE RESEARCH
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2024
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IF 10.9
Ya-Jun Wang,Xiao-Pei Zhang,Dong-Mei Liu,Jun-Guo Li,Jian-Bao Zhang,Yu-Wei Zhang,Ya-Nan Zeng,Yi-Tong Wang,Bao Liu,Xi Zhang,Ya-Jing Zhang
Ca 2 SiO 4 is the primary carbonation-reactive mineral in steel slag, and demonstrates significant carbon sequestration potential, yet its microscopic reaction processes remain unclear. This study investigated the carbonation behavior of Ca 2 SiO 4 using ReaxFF MD simulations. The results indicated that as CO 2 concentration increased, the capture rate of Ca 2 SiO 4 decreased, and the molecular structure of the resulting CaCO 3 varied in oxygen origin. At room temperature, the carbonation rate of Ca₂SiO₄ gradually decreased over time until it reached equilibrium. Increasing the temperature could reactivate the carbonation, but the rate would still decline until it reached equilibrium again. Higher temperatures could accelerate the formation of the intermediate C 2 O 5 2− and internal CO 3 2− diffusion, thereby boosting the carbonation and increasing CO 2 adsorption. This study investigated the carbonation of Ca 2 SiO 4 at the atomic level, aiming to link microscopic molecular processes with macroscopic experimental phenomena, thereby providing a theoretical foundation for enhancing the carbonation efficiency of steel slag.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Wei Feng,Mo Zheng,Jin Bai,Xianxian Zhang,Chuang Wu,Zhenxing Guo,Lingxue Kong,Zongqing Bai,Wen Li
Understanding the effects of co-pyrolysis synergies between low-rank coal and high-density polyethylene (HDPE) on the carbon structure evolution in char and the relationship between char structure and chemical bonds evolution is very needed. A combination of ReaxFF MD and experimental approaches provides an opportunity for fully understanding the dynamic profiles of char structures and coking trends during co-pyrolysis process of coal and HDPE. In this work, consistent conclusions were obtained from fixed-bed experiments and ReaxFF MD simulations in product distribution during both individual coal pyrolysis and co-pyrolysis at different temperatures. The ReaxFF MD simulation results reveal that adding HDPE partially inhibited the coking process of coal char. The RDF results indicated higher order degree and aromaticity exist in coal/HDPE(7:3)-Char when compared to those in coal-Char, which agrees well with the findings from XRD and FTIR approaches. By analyzing the evolution of C=C, C=O, C-O, C( sp 2 )-C( sp 3 ), C( sp 3 )-C( sp 3 ) and C( sp 2 )-H bonds in C 40 + fragments during secondary simulations of co-pyrolytic char, it was observed that the structural order and aromaticity of co-pyrolytic char increase with temperature, and the oxygen-containing bonds are the initial recombination sites for char formation. These findings provide rich theoretical information to complement the understanding of char structure in co-fed systems and the interaction between coal and HDPE blend.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
·
2024
·
IF 9
Wei Yu,Chao Liu,Xijie Ban,Liyong Xin,Shukun Wang
When siloxanes are used as the working fluids of organic Rankine cycle systems, there is a possibility of air infiltration due to the large vacuum present in the condenser. To address this issue, experimental and simulation studies were conducted on the thermal stability and pyrolysis product characteristics of octamethyltrisiloxane (MDM) in the presence of air. The results indicated that air significantly promotes the decomposition of MDM at the temperatures above 250 °C. Air was helpful in increasing the formation of CH 2 O, CO, and CO 2 , and also enhanced polymerization of decomposition product of siloxane, leading to higher yields of MD 2 M, MD 3 M, MD 4 M, D 3 , D 4 , and D 5 . By combining reactive force field molecular dynamics (ReaxFF-MD) simulations with density functional theory (DFT) calculations, the microscopic mechanisms of MDM's oxidative decomposition by O 2 in air and H 2 O under humid conditions were elucidated. O 2 can easily combine with unsaturated Si atoms to form Si-O bonds, combine with CH 3 radicals to form C-O bonds, and undergoes hydrogen extraction reactions to initiate decomposition. H 2 O mainly undergoes initial decomposition through CH 3 radical hydrogenation and binding with unsaturated Si atoms. The generated O 2 H, O, and OH radicals tend to bind with Si atoms in molecules and radicals, facilitating polymerization reactions.
研究领域:
化学工程
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材料科学
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计算化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Wei Feng,Mo Zheng,Lijun Jin,Jin Bai,Lingxue Kong,Huaizhu Li,Zongqing Bai,Wen Li
Co-pyrolysis of waste plastics and low-rank coal is a promising approach to deal with the serious waste crisis and improve the clean utilization of low-rank coal. In this work, the comprehensive co-pyrolysis behaviors of low-rank coal and polyethylene plastics were explored systematically by combining TG experiment, in-situ Py-TOF-MS technique, and ReaxFF MD simulation. The consistent results were obtained among three approaches to demonstrate the positive interaction exists between coal and PE during the co-pyrolysis process, which leads to volatile yield increasing with PE addition. TG experimental results showed that the blending ratio of 7:3 for coal and PE has the strongest synergy during the co-pyrolysis process, while Py-TOF-MS experimental results unraveled that the synergistic effect of coal and PE was determined by changing the content of pyrolysis products rather than by producing cross-reaction products. The PE addition significantly reduced the yield of MAHs and normal alkyl-substituted monophenols and increased the yield of olefins, alkanes, and aromatic derivatives. ReaxFF MD simulation results complement the experimental observation to obtain similar weight loss profiles with TG experiments and consistent identification of major representative tar pyrolyzates with Py-TOF-MS experiments. Particularly, the detailed gas evolving trends and the underlying bond-breaking reactions of C C, C O, and C H bonds were revealed by ReaxFF MD, which indicates PE addition promotes bond breaking of C C and C H to enhance more tar generation. The combination of experiments and ReaxFF MD simulations can capture the comprehension of the co-pyrolysis process between low-rank coal and PE, which can be extended to other co-pyrolysis applications for related solid fuels.
研究领域:
能源与燃料化学
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
CARBON
·
2024
·
IF 10.5
Q. Chen,I.M. De Cachinho Cordeiro,W. Yang,A.C.Y. Yuen,T.B.Y. Chen,W. Wang,W. Yang,G.H. Yeoh,R.K.K. Yuen
Graphdiyne (GDY) is an emerging two-dimensional carbon allotrope comprising unique sp 1 and sp 2 hybridisation, which has attracted extensive investigation into various applications, especially as battery component materials owing to its excellent electromechanical properties. However, GDY's thermal stability and oxidation behaviour have yet to be evaluated, which is crucial to safety in high-energy applications. The present study characterised the thermophysical properties of GDY via reactive molecular dynamics (MD-ReaxFF) and experimental measurement. The oxidation kinetics and decomposition behaviour were elucidated and benchmarked with graphene (GP) and graphyne (GY) to investigate the correlation between thermal stability and morphology of carbon nanomaterials. The simulation results revealed the initial oxidation mechanism of GDY sheets, where the cleavage of C–C bonds was observed at the acetylenic chain and could be identified as the weak spots of the structural stability. As for oxidation kinetics, GDY's experimental and numerical activation energy was found to be 173.1 and 133 kJ/mol, which is lower than 220.8 kJ/mol of GP. The current work pioneer investigated the thermal stability of GDY using both experimental and numerical approaches. Meanwhile, different oxidation mechanisms between GP and GDY were distinguished and demonstrated in detail.
研究领域:
材料科学
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化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2024
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IF 5.8
Hongdi Yu,Fawei Lin,Xuan Guo,Chujun Luan,Eslam Salama,Mona Ossman,Xinghua Liu,Rundong Li,Jiantao Li,Lei Che,Wangyang Tian,Beibei Yan,Guanyi Chen
Pyrolysis of oily sludge (OS) possesses dual advantages of oil recovery and harmless treatment. Exploring the reaction pathway for petroleum hydrocarbons during pyrolysis in the presence of minerals is critical for optimizing pyrolysis parameters. This study selected six pure soil minerals and five typical oil compounds as representative to simulate OS samples. Model compounds are more helpful deriving and clarifying the internal mechanism. The mixed oil compounds were continuously loading fed into reactor loaded with varied minerals, which was facilitated the detection of pyrolytic products. Meanwhile, the pyrolysis reaction pathways of oil compounds at different temperature and pressure were simulated by ReaxFF MD. According to the experimental results, high temperature increased the content of light hydrocarbons and gas products (i.e., C 3 H 4 , C 4 H 8 , CH 4 , and H 2 ). Montmorillonite (MT) and illite (IT) exhibited catalytic ring-opening and cracking effects as alkaline minerals, while the kaolin (KL) presented catalytic aromatization effects. The catalytic ring-opening effect of calcite (CA) and hematite (MA) was equally evident, but quartz (QA) possessed a weak catalytic effect and even promoted condensation . n-Dodecane (ND) and 1-dodecene (1-DE) had more complicated pathways compared to other com-pounds with stable rings. The main cracking reaction pathway of ND was the breakage of β C C bond, and the C C bond at both ends was easier to break than the one in the middle. The pyrolysis reaction pathway of 1-DE not only included the breakage of β C C bond, and the generation of ethyl radicals. The methyl groups in methylcyclohexane (MC), methylbenzene (MB), and 1-methylnaphthalene (1-ME) could be detached, while ring-opening reactions generated free radicals . This work provides detailed explanation of pyrolysis reaction pathway of oil compounds and the catalytic mechanism of soil minerals, which helps us understand OS pyrolysis process.
研究领域:
环境化学
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能源工程
·
石油污染治理
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热解机理
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计算化学
✓ 已验证
DOI
高影响因子
ENERGY
·
2023
·
IF 9
Wei Yu,Chao Liu,Luxi Tan,Qibin Li,Liyong Xin,Shukun Wang
The thermal stability and decomposition mechanism of octamethyltrisiloxane (MDM) were studied using a combination of experimental, ReaxFF simulation, and DFT calculation techniques. After heating MDM for 24 h at 250 °C and 1 MPa, the signature product CH 4 was detected, along with liquid products such as hexamethyldisiloxane (MM) and decamethyltetrasiloxane (MD 2 M). The decomposition rate of MDM remained relatively constant in the temperature range of 250 °C–320 °C but exhibited a sharp increase at 350 °C. Higher pressure was found to promote MDM polymerization. The oxygen (O) atoms displayed a large negative electrostatic potential , while the hydrogen (H) and silicon (Si) atoms exhibited a large positive potential. The electrostatic interaction facilitated the rearrangement reactions, with O and carbon (C) atoms being the most reactive for electrophilic and free radical reactions. The thermal decomposition of MDM initiated with the cleavage of Si–C bonds. Hydrogen extraction reactions between methyl radicals and MDM, as well as Si–O bond rearrangement reactions of demethylated radicals with MDM, further promoted MDM decomposition and the formation of CH 4 and siloxane oligomers . These findings are significant for the safe application of MDM as a working fluid in ORC system.
研究领域:
化学工程
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材料科学
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计算化学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2024
·
IF 5.2
Yuchuan Feng,Penghui Wang,Nana Wang,Xin Guo,Suxia Ma
Reactive force field molecular dynamics (ReaxFF MD) simulation and experiments were employed to deeply reveal the sintering mechanism of Fe2O3 particles during iron-based chemical looping combustion. The sintering process of Fe2O3 particles was simulated at different temperatures (973–1273 K). The results showed that the temperature increase has limited effect on the structure of Fe2O3 particles and slightly increases the atomic irregularity. The sintering process of Fe2O3 particles can be divided into three stages: the proximity phase, rapid formation, and slow growth of the sintering neck. The temperature increase significantly promotes the sintering process of Fe2O3 particles. The mean-square displacement and Arrhenius equations were used to study the atomic diffusion properties of Fe2O3 particles. The diffusion activation energy of surface atoms is lower than that of inner atoms, implying that the surface atoms have stronger diffusion ability. With the increase of temperature, more Fe atoms diffuse toward the interface of Fe2O3 particles. Increasing the temperature can accelerate the diffusion and enrichment of surface atoms, especially Fe, toward the sintering neck region, resulting in more serious sintering of Fe2O3 particles. ReaxFF MD simulation is in good agreement with the experimental results. Inhibiting the atomic diffusion is the key to improving the antisintering ability of Fe2O3 oxygen carriers.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
BIOMASS & BIOENERGY
·
2026
·
IF 7
Fang Xu,Mingjun Liu,Wenxiao Wang,Mohan Zhao,Rui Zhang,Shuang Wu,Shuo Pan,Jingru Bai,Qing Wang
The synergistic mechanism of lignin and PS was investigated at multiple scales. • The addition of PS effectively improved the quality of bio-oil derived from lignin. • The addition of PS promoted C-C bond cleavage while suppressing C-O bond cleavage. • The synergistic effect of lignin and PS significantly inhibited secondary reactions. The co-pyrolysis of lignin with waste plastics serves as an effective approach for both upgrading lignin-derived oil and mitigating white pollution. In this study, the synergistic mechanism of lignin and polystyrene (PS) co-pyrolysis was comprehensively explored through a combination of experiments, ReaxFF-MD simulations, and kinetic analysis. TG analysis revealed a notable interaction between lignin and PS during co-pyrolysis, which facilitated the release of volatiles. Both Py-GC/MS and ReaxFF-MD findings demonstrated that the introduction of PS significantly improved oil quality, facilitating the production of non-oxygenated compounds. ReaxFF-MD simulations further elucidated the role of synergy in oil production and chemical bond evolution. The findings indicated that PS donated abundant active radicals that promoted the rupture of C-C bonds while suppressing the rupture of C-O bonds, guiding the reaction pathway toward the formation of oil, especially non-oxygenated oil. Moreover, PS further stabilized oil through radical stabilization effects, suppressing the secondary reactions. Kinetic analysis indicated that lignin and PS displayed positive synergy during co-pyrolysis, greatly reducing the apparent activation energy. This study provides theoretical guidance for the preparation of high quality oil via lignin/plastics co-pyrolysis.
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Li Zhou,Fashe Li,Wenchao Wang,Huicong Zhang,Yaozong Duan,Hua Wang
Phospholipids, as key trace constituents of biodiesel, can have complex effects on the performance of biodiesel. Exploring the mechanism of their influence on the pyrolysis and oxidation characteristics of biodiesel is crucial for controlling the generation and emission of pollutants. To this end, this study employed TG-FTIR-MS experimental technology and the ReaxFF-MD simulation method to investigate the effects of phosphatidylethanolamine (PE) on the activation energy ( E a ), gaseous product generation, and mechanism of Jatropha biodiesel pyrolysis and oxidation reactions. The results indicated that the addition of 400 ppm PE can reduce the pyrolysis E a of Jatropha biodiesel from 87.25 kJ/mol to 80.67 kJ/mol, consistent with simulated E a of 93.35 kJ/mol and 81.81 kJ/mol, respectively. This notably promoted the initial oxidation stage of the Jatropha biodiesel reaction, facilitating the generation of oxidation products such as CO and C 2 H 4 . In the pyrolysis reaction, PE promoted C 2 H 4 formation, primarily through reactions involving hydrocarbon small free radicals. In the oxidation reaction, the addition of PE increased the number and variety of active free radicals in the system, with the formation reactions of H 2 O and CH 2 O involving phosphorus-containing oxygen groups. Furthermore, a small amount of nitrogenous free radicals participates in the formation reactions of C 2 H 4 and CO.
研究领域:
能源科学
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化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
ACS Omega
·
2023
·
IF 4.1
Jinghui Xu,Lianyi Zhu
Copyrolysis is a potential method for the collaborative disposal of biomass and plastics. There is an interaction between biomass and plastics during copyrolysis. In this work, a combination of ReaxFF-MD simulation and experimental validation was used to investigate the pyrolysis reaction process of the biomass and plastic, observing the evolution of free radicals at the molecular level and exploring the distribution of pyrolysis products. TG-MS results show that reaction temperature ranges for cellulose and PVC are 296–400 and 267–480 °C, respectively. HCl is the main product of PVC pyrolysis, and mixing with cellulose will reduce the yield of HCl. The ReaxFF method was used to model the pyrolysis of cellulose and PVC. The modeling temperature is much higher than the real reaction temperature, which is attributed to the time scale of picoseconds of ReaxFF-MD modeling. Modeling results show that the yield of HCl of the cellulose/PVC mixture is obviously lower than that of pure PVC. When mixed with cellulose, the HCl release is largely inhibited and more chlorine elements are retained in the pyrolysis hydrocarbon fraction or solid products.
研究领域:
能源与燃料化学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2025
·
IF 6.2
Fang Xu,Rui Zhang,Mingjun Liu,Shuang Wu,Da Cui,Jingru Bai,Qing Wang
To address the growing challenges of energy crisis and white pollution, co-pyrolysis of lignin and plastics facilitates both biomass resource valorization and pollution mitigation. To gain deeper insight into the synergistic mechanism, this study combined experiments, kinetic analyses, and molecular simulations to systematically investigate the product distributions and bond-breaking behaviors during lignin/PE co-pyrolysis at multiple scales. The kinetic investigation demonstrated that lignin and PE interaction exhibited a positive synergistic effect, significantly lowering the activation energy. Moreover, adding PE promoted the formation of oxygen-free tar while suppressing oxygen-containing tar, consequently enhancing the fuel properties of pyrolysis tar. In parallel, ReaxFF-MD simulations provided molecular-level insights into the dynamic behaviors of chemical bonds during co-pyrolysis. The results demonstrated that lignin/PE co-pyrolysis facilitated C—C bonds breaking but inhibited C—O bonds cleavage, thereby significantly increasing the production of hydrocarbon gases. TG analysis indicated that the interaction between lignin and PE facilitated the release of volatile products. The simulations complemented experimental observations in the secondary reaction stage, demonstrating synergistic promotion of tar formation while inhibiting pyrolysis gas release. This work elucidated the synergistic mechanism of lignin/PE co-pyrolysis at multiple scales, providing theoretical support for the clean conversion and resource recovery of lignin and plastic waste.
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）