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The Innovation 2024年第2期5卷 79-87页

作者： Huan Ma Yueyue Jiao Wenping Guo Xingchen liu yongwang li Xiaodong Wen State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China University of Chinese Academy of Sciences Beijing 100049China National Energy Center for Coal to liquids Synfuels China Co.Ltd.Beijing 101400China Beijing Advanced Innovation Center for Materials Genome Engineering IndustryUniversity Cooperation Base between Beijing Information S&T University and Synfuels China Co.Ltd.Beijing 100101China

Solid surfaces usually reach thermodynamic equilibrium through particle exchange with their environment under reactive conditions.A prerequisite for understanding their functionalities is detailed knowledge of the surface composition and atomistic geometry under working conditions.Owing to the large number of possible Miller indices and terminations involved in multielement solids,extensive sampling of the compositional and conformational space needed for reliable surface energy estimation is beyond the scope of ab initio calculations.Here,we demonstrate,using the case of iron carbides in environments with varied carbon chemical potentials,that the stable surface composition and geometry of multielement solids under reactive conditions,which involve large compositional and conformational spaces,can be predicted at ab initio accuracy using an approach that combines the bond valence model,Gaussian process regression,and ab initio thermodynamics.Determining the atomistic structure of surfaces under working conditions paves the way toward identifying the true active sites of multielement catalysts in heterogeneous catalysis.

关键词： surfaces solids environments

Active learning to overcome exponential-wall problem for effective structure prediction of chemical-disordered materials

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npj Computational Materials 2023年第1期9卷 2243-2251页

作者： Xiaoze Yuan Yuwei Zhou Qing Peng Yong Yang yongwang li Xiaodong Wen State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China National Energy Center for Coal to Clean Fuels Synfuels China Technology Co.LtdHuairou DistrictBeijing 101400China The State Key Laboratory of Nolinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China Beijing Advanced Innovation Center for Materials Genome Engineering Industry–University Cooperation Base between Beijing Information S&T University and Synfuels China Technology Co.LtdBeijingChina School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China

Chemical-disordered materials have a wide range of applications whereas the determination of their structures or configurations isone of the most important and challenging problems. Traditional methods are extremely inefficient or intractable for large systemsdue to the notorious exponential-wall issue that the number of possible structures increase exponentially for N-body systems.Herein, we introduce an efficient approach to predict the thermodynamically stable structures of chemical-disordered materials viaactive-learning accompanied by first-principles calculations. Our method, named LAsou, can efficiently compress the samplingspace and dramatically reduce the computational cost. Three distinct and typical finite-size systems are investigated, including theanion-disordered BaSc(O_(x)F_(1−x))3 (x = 0.667), the cation-disordered Ca_(1−x)Mn_(x)CO_(3) (x = 0.25) with larger size and the defect-disordered ε-FeC_(x) (x = 0.5) with larger space. The commonly used enumeration method requires to explicitly calculate 2664, 1033,and 10496 configurations, respectively, while the LAsou method just needs to explicitly calculate about 15, 20, and 10configurations, respectively. Besides the finite-size system, our LAsou method is ready for quasi-infinite size systems empoweringmaterials design.

关键词： disordered exponential configuration

Computer generation of detailed reaction networks in hydrocracking of Fischer-Tropsch wax

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Chinese Journal of Chemical Engineering 2022年第1期35卷 342-349页

作者： Jingjing Wang Wei Zhao Kunpeng Song Hongwei Xiang liping Zhou Yong Yang yongwang li State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China National Energy Center for Coal to liquids Synfuels China Co.Ltd.Huairou DistrictBeijing 101400China University of Chinese Academy of Sciences Beijing 100049China

Fischer-Tropsch synthesis(FTS)wax is a mixture of linear hydrocarbons with carbon number from C7 to C70+.Converting FTS wax into high-quality diesel(no sulfur and nitrogen contents)by hydrocracking technology is attractive in economy and practicability.Kinetic study of the hydrocracking of FTS wax in elementary step level is very challenging because of the huge amounts of reactions and species involved.Generation of reaction networks for hydrocracking of FTS wax in which the chain length goes up to C70 is described on the basis of Boolean adjacency matrixes.Each of the species(including paraffins,olefins and carbenium ions)involved in the elementary steps is represented digitally by using a(N+3)N matrix,in which a group of standardized numbering rules are designed to guarantee the unique identity of the species.Subsequently,the elementary steps are expressed by computer-aided matrix transformations in terms of proposed reaction rules.Dynamic memory allocation is used in species storage and a characteristic vector with nine elements is designed to store the key information of a(N+3)N matrix,which obviously reduces computer memory consumption and improves computing efficiency.The detailed reaction networks of FTS wax hydrocracking can be generated smoothly and accurately by the current method.The work is the basis of advanced elementary-step-level kinetic modeling.

关键词： Hydrocracking Fischer-Tropsch synthesis wax Boolean adjacency matrixes Reaction network

Speeding up the prediction of C-O cleavage through bond valence and charge on iron carbides

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矿物冶金与材料学报:英文版 2023年第10期30卷 2014-2024页

作者： Yurong He Kuan Lu Jinjia liu Xinhua Gao Xiaotong liu yongwang li Chunfang Huo James P.Lewis Xiaodong Wen Ning li Beijing Advanced Innovation Center for Materials Genome Engineering Beijing Information Science&Technology UniversityBeijing 101400China State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering College of Chemistry and Chemical EngineeringNingxia UniversityYinchuan 750021China State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China National Energy Center for Coal to liquids Synfuels China Co.Ltd.Beijing 101400China Hong Kong Quantum AI Laboratory Ltd.University of Hong KongHong Kong 999077China

The activation of CO on iron-based materials is a key elementary reaction for many chemical processes.We investigate CO adsorption and dissociation on a series of Fe,Fe_(3)C,Fe_(5)C_(2),and Fe_(2)C catalysts through density functional theory calculations.We detect dramatically different performances for CO adsorption and activation on diverse surfaces and sites.The activation of CO is dependent on the local coordination of the molecule to the surface and on the bulk phase of the underlying catalyst.The bulk properties and the different local bonding environments lead to varying interactions between the adsorbed CO and the surface and thus yielding different activation levels of the C-O bond.We also examine the prediction of CO adsorption on different types of Fe-based catalysts by machine learning through linear regression models.We combine the features originating from surfaces and bulk phases to enhance the prediction of the activation energies and perform eight different linear regressions utilizing the feature engineering of polynomial representations.Among them,a ridge linear regression model with2nd-degree polynomial feature generation predicted the best CO activation energy with a mean absolute error of 0.269 eV.

关键词： adsorption CO activation iron carbides density functional theory

Effect of manganese on the catalytic performance of an iron-manganese bimetallic catalyst for light olefin synthesis

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Journal of Energy Chemistry 2013年第4期22卷 624-632页

作者： Tingzhen li Hulin Wang Yong Yang Hongwei Xiang yongwang li State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of Sciences College of Chemistry and Environmental Engineering Chongqing Three Gorges University Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education Southeast University

A systematic study was carried out to investigate the promotion effect of manganese on the performance of a coprecipitated iron-manganese bimetallic catalyst for the light olefins synthesis from syngas. The catalyst samples were characterized by N2 physisorption, transmis- sion electron microscopy （TEM）, X-ray photoelectron spectroscopy （XPS）, powder X-ray diffraction （XRD）, Mossbauer spectroscopy, H2- differential thermogravimetric analysis （H2-DTG）, CO temperature-programmed reduction （CO-TPR） and CO2 temperature-programmed des- orption （CO2-TPD）. The Fischer-Tropsch synthesis （FTS） performance of the catalyst was measured at 1.5 MPa, 250 ℃ and syngas with H2/CO ratio of 2.0. The characterization results indicated that the addition of manganese decreases the catalyst crystallite size, and improves the catalyst BET surface area and pore volume. The presence of manganese suppresses the catalyst reduction and carburization in H2, CO and syngas, respectively. The addition of manganese improves the catalytic activity of water-gas shift reaction and suppresses the oxidation of iron carbides in the FTS reaction. The incorporation of manganese improves the catalyst surface basicity and results in a significant improvement in the selectivities to light olefins and heavy hydrocarbons （C5＋）, and furthermore an inhibition of methane formation in FTS. The pure iron catalyst （Mn-00） has the highest initial FTS catalytic activity （65%） and the lowest selectivity （17.35 wt%） to light olefins （C2=-C4=）. The addition of an appropriate amount of manganese can improve the catalyst FTS activity.

关键词： light olefin Fischer-Tropsch synthesis iron-manganese bimetallic catalyst carburization

近、远场地震作用下深水高墩桥梁水动力效应研究

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中国铁路 2024年第1期 57-66页

作者：李明开永旺浙江交通职业技术学院轨道交通学院浙江杭州311112 浙江交通职业技术学院路桥学院浙江杭州311112

为研究近、远场地震作用下水动力效应对深水高墩桥梁抗震性能的影响,明确深水高墩桥梁抗震性能分析中考虑动水压力的必要性,以典型的深水高墩大跨连续刚构桥为例,基于OpenSees建立其非线性动力分析模型。通过附加质量法模拟墩-水动力相... 详细信息

为研究近、远场地震作用下水动力效应对深水高墩桥梁抗震性能的影响,明确深水高墩桥梁抗震性能分析中考虑动水压力的必要性,以典型的深水高墩大跨连续刚构桥为例,基于OpenSees建立其非线性动力分析模型。通过附加质量法模拟墩-水动力相互作用,并在PEER数据库选择代表性的近场和远场地震动记录,对该桥梁进行不同水深下的非线性地震响应分析,对比研究近、远场地震作用下动水压力效应对深水高墩桥梁抗震性能的影响。研究表明:不论近场还是远场地震作用,墩-水相互作用都会显著增大桥梁结构的地震响应,近场地震作用下,对桥墩的墩顶位移和墩底曲率的改变率分别可达到64.77%和156%;与远场地震作用相比,近场地震作用下墩-水相互作用对深水高墩桥梁抗震性能的影响更为显著,在近场地区的深水高墩桥梁抗震性能分析中,应充分考虑近断层地震动和墩-水相互作用的耦合效应;近场地震作用下,墩-水相互作用主要激起桥墩的一阶振型产生基频共振,增大墩底的损伤,而远场地震作用下墩-水相互作用会激起桥墩的高阶振型,不仅增大墩底的损伤而且会加剧墩身中上部的损伤;深水高墩桥梁抗震性能分析不仅需要考虑动水压力效应,还应考虑近场和远场地震动带来的影响。

关键词：高墩桥梁动水效应抗震性能近、远场地震

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自驱修孔钻头动力参数及钻齿结构研究

煤田地质与勘探 2024年第4期52卷 179-189页

作者：刘勇李阳魏建平苑永旺代硕李林豫河南理工大学瓦斯地质与瓦斯治理国家重点实验室培育基地河南焦作454000 河南理工大学煤炭安全生产与清洁高效利用省部共建协同创新中心河南焦作454000

自驱修孔钻头是修复失效长钻孔的有效技术手段,为进一步提高修孔速度和瓦斯抽采效果,本文基于射流反冲理论,分析了射流反冲力与喷嘴参数的关系,构建了自驱修孔钻头旋转力学理论模型。采用LS-DYNA开展不同结构钻齿破煤过程,分析了不同钻... 详细信息

自驱修孔钻头是修复失效长钻孔的有效技术手段,为进一步提高修孔速度和瓦斯抽采效果,本文基于射流反冲理论,分析了射流反冲力与喷嘴参数的关系,构建了自驱修孔钻头旋转力学理论模型。采用LS-DYNA开展不同结构钻齿破煤过程,分析了不同钻进压力和扭矩作用下钻齿对煤体破坏形式和钻齿破煤体积变化规律,并开展了破煤实验验证数值模拟结果。形成了自驱修孔钻头参数确定方法,设计了自驱修孔钻头,并在郑煤集团超化煤矿22煤柱面底抽巷进行了工程实验。研究结果表明:(1)喷嘴张角α和偏心角β是决定钻进压力和扭矩分配的关键参数,通过调控张角和偏心角可实现钻进压力和扭矩的最优匹配。(2)相同钻进参数条件下,钻齿结构对破煤体积影响较大,阶梯钻齿破煤效果最优。在钻进压力为120N、扭矩0.6N·m时,阶梯型钻齿结构的修孔钻头能够实现钻进压力和扭矩最优匹配。(3)确定了最优修孔钻头结构参数为:钻头外径28 mm;后置喷嘴张角20°,偏心角90°;前置喷嘴张角90°,偏心角0°。(4)工程应用结果表明:瓦斯抽采纯量提高了1.96倍,瓦斯抽采体积分数提高了3.98倍,修孔速度提高了1.2倍。通过改进钻头动力参数及优化钻齿结构,设计的自驱修孔钻头在工程实践中达到了提高修孔速度和瓦斯抽采效果的目的。

关键词：瓦斯抽采钻孔修复钻进压力钻齿结构煤矿

Activation pressure studies with an iron-based catalyst for slurry Fischer-Tropsch synthesis

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Journal of Natural Gas Chemistry 2009年第4期18卷 429-435页

作者： Qinglan Hao liang Bai Hongwei Xiang yongwang li College of Material Science ＆ Chemical Engineering Tianjin University of Science ＆ Technology Tianjin 300457 China State Key Laboratory of Coal Conversion Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan 030001 Shanxi China

Fischer-Tropsch synthesis （FTS） was carried out with an industrial iron-based catalyst （100Fe/5Cu/6K/16SiO2, by weight） under the baseline conditions in a stirred tank slurry reactor （STSR）. The effects of activation pressure on the catalyst activity and selectivity were investigated. It was found that iron phase compositions, textural properties, and FTS performances of the catalysts were strongly dependent on activation pressure. The high activation pressure retards the carburization. MФssbauer effect spectroscopy （MES） results indicated that the contents of the iron carbides clearly decrease with the increase of activation pressure, especially for the activation pressure increasing from 1.0 MPa to 1.5 MPa, and the reverse trend is observed for superparamagnetic Fe^3＋（spm）. The higher content of Fe^3＋（spm） results in the higher amount of CO2 in tail gas when the catalyst is reduced at higher pressure. The catalyst activity decreases with the increase of activation pressure. The high quantity of iron carbides is necessary to obtain high FTS activity. However, the activity of the catalyst activated in syngas can not be predicted solely from the fraction of the carbides. It is concluded that activation with syngas at the lower pressure would be the most desirable for the better activity and stability on the iron-based catalyst.

关键词： wFischer-Tropsch synthesis spray-dried iron catalyst activation pressure slurry reactor MCssbauer effect spectroscopy

Study of Manganese Promoter on a Precipitated Iron-Based Catalyst for Fischer-Tropsch Synthesis

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Journal of Natural Gas Chemistry 2007年第3期16卷 278-285页

作者： Zhichao Tao Yong fang Chenghua Zhang Tingzhen li Mingyue Ding Hongwei Xiang yongwang li State Key Laboratory of Coal Conversion Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan 030001 Shanxi China Graduate University of Chinese Academy of Sciences Beijing 100039 China

The effects of Manganese （Mn） incorporation on a precipitated iron-based Fischer-Tropsch synthesis （FTS） catalyst were investigated using N2 physical adsorption, air differential thermal analysis （DTA）, H2 temperature-programmed reduction （TPR）, and Mǒssbauer spectroscopy. The FTS performances of the catalysts were tested in a slurry phase reactor. The characterization results indicated that Mn increased the surface area of the catalyst, and improved the dispersion of （α-Fe2O3 and reduced its crystallite size as a result of the high dispersion effect of Mn and the Fe-Mn interaction. The Fe-Mn interaction also suppressed the reduction of （α-Fe2O3 to Fe3O4, stabilized the FeO phase, and （or） decreased the carburization degree of the catalysts in the H2 and syngas reduction processes. In addition, incorporated Mn decreased the initial catalyst activity, but improved the catalyst stability because Mn restrained the reoxidation of iron carbides to Fe3O4, and improved further carburization of the catalysts. Manganese suppressed the formation of CH4 and increased the selectivity to light olefins （C2-4^=）, but it had little effect on the selectivities to heavy （C5＋） hydrocarbons. All these results indicated that the strong Fe-Mn interaction suppressed the chemisorptive effect of the Mn as an electronic promoter, to some extent, in the precipitated iron-manganese catalyst system.

关键词： Fischer-Tropsch synthesis iron-manganese catalyst manganese promoter Fe-Mn interaction

Effect of Manganese Incorporation Manner on an Iron-Based Catalyst for Fischer-Tropsch Synthesis

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Journal of Natural Gas Chemistry 2007年第3期16卷 244-251页

作者： Tingzhen li Yong Yang Chenghua Zhang Zhichao Tao Haijun Wan Xia An Hongwei Xiang yongwang li State Key Laboratory of Coal Conversion Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan 030001 Shanxi China Graduate University of the Chinese Academy of Sciences Beijing 100029 China

A systematic study was undertaken to investigate the effects of the manganese incorporation manner on the textural properties, bulk and surface phase compositions, reduction/carburization behaviors, and surface basicity of an iron-based Fischer-Tropsch synthesis （FTS） catalyst. The catalyst samples were characterized by N2 physisorption, X-ray photoelectron spectroscopy （XPS）, H2 （or CO） temperature-programmed reduction （TPR）, CO2 temperature-programmed desorption （TPD）, and M5ssbauer spectroscopy. The FTS performance of the catalysts was studied in a slurry-phase continuously stirred tank reactor （CSTR）. The characterization results indicated that the manganese promoter incorporated by using the coprecipitation method could improve the dispersion of iron oxide, and decrease the size of the iron oxide crystallite. The manganese incorporated with the impregnation method is enriched on the catalyst＇s surface. The manganese promoter added with the impregnation method suppresses the reduction and carburization of the catalyst in H2, CO, and syngas because of the excessive enrichment of manganese on the catalyst surface. The catalyst added manganese using the coprecipitation method has the highest CO conversion （51.9%） and the lowest selectivity for heavy hydrocarbons （C12＋）.

关键词： Fischer-Tropsch synthesis iron-based catalyst manganese promoter incorporation manner