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Prediction of the severe slugging period in gas-liquid two-phase pipeline-riser systems using an artificial neural network

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Energy 2025年 331卷

作者： Chang, Yingjie Xu, Qiang Huang, Bo Zhang, Xuemei Yu, Haiyang Chen, Hao Thévenin, Dominique Guo, Liejin Shaanxi Key Laboratory of New Transportation Energy and Automotive Energy Saving School of Energy and Electrical Engineering Chang'an University Xi'an710064 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Laboratory of Fluid Dynamics and Technical Flows Otto-von-Guericke-Universität Magdeburg Magdeburg39106 Germany

Severe slugging flow (SS) is a very harmful flow regime found during oil and gas transportation. An accurate prediction of the SS period would help to obtain the needed conditions for regime transition models, which are essential when designing and operating an oil and gas field. However, previous empirical correlations are limited to specific flow and structural conditions, resulting in significant errors whenever these parameters deviate. Gas-liquid two-phase flow experiments in a pipeline-riser system were carried out and used as additional training data. The analysis of scatter matrix and correlation coefficient was used to determine the most relevant features impacting SS period. Then, a prediction model based on an artificial neural network (ANN) was established with one single output (the SS period) and seven input features, including five pipeline structural parameters and two flow parameters. The prediction errors coming with previous empirical models are much larger than those of our ANN model. While the relative errors of the empirical models range from −95 % to 3000 %, the ANN has a prediction error within a range of 25 % and a mean absolute error of only 11.3 %, showing a significant improvement over previous predictions. © 2025 Elsevier Ltd

关键词： Gas industry

Proposal design and thermodynamic analysis on a novel coal-based power generation system integrated with CO2 capture

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Proposal design and thermodynamic analysis on a novel coal-b...

Electrical engineering and Mechatronics Technology (ICEEMT), IEEE International Conference on

作者： Guobin Gao Ruiqi Mu Yali Yang Lei Yan Jun Gao Ming Liu Guoneng Jinjie Energy Co. Ltd Yulin China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China

To enhance the energy efficiency and decrease the carbon emissions, a novel coal-based power generation system integrated with CO 2 capture is proposed in this study. The S-CO 2 cycle is integrated to recover the waster heat of system effectively. The heat transfer processes are well matched, and the irreversibility of heat exchangers in the system is reduced by splitting working medium appropriately. The system simulation and thermodynamic analysis models are developed. The energy and exergy efficiency of system are 51.32% and 50.07%, respectively. The system efficiency increases with the increase of the coal water slurry concentration (CWSC) and the decrease of the gasification temperature. When the CWSC is 35% and gasification temperature is 500 °C, the exergy efficiency of system reaches 51.74% and 50.59%, respectively.

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Water Washing of Biomass and Biochar

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SSRN 2022年

作者： Huang, Xiaole Tie, Yuan Jiang, Jiahao Deng, Lei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China

To investigate the differences in organics composition between leachates of biomass and biochar, four biomass materials and the corresponding biochar are water washed. GC-MS is employed to characterize the distributions of organic components in leachates. Raw and washed biomass, and biomass leachates dried at 333 K are sent for TG/DTG analysis. The results show that corn and sorghum stalks should be washed after the high-temperature pyrolysis at 303 K, with aromatic hydrocarbon contents of 11.00% and 29.95%, respectively. It is proposed that wheat straw and rice husk should be washed directly. Considering the contents of alkanes, cycloalkanes, and heterocyclic hydrocarbon in leachates, biomass should be pyrolyzed at a relatively low temperature and then be washed. It is recommended to wash biomass directly to inhibit the acidic organic release. Washed and raw biomass samples have the similar DTG curves. The combustion of dried leachate is more complicated, with one or two peaks during the third stage. The activation energy follows an order of washed biomass > raw biomass > biomass leachate. © 2022, The Authors. All rights reserved.

关键词： Biomass

Electron-Deficient Zn-N_(6) Configuration Enabling Polymeric Carbon Nitride for Visible-Light Photocatalytic Overall Water Splitting

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Nano-Micro Letters 2022年第12期14卷 602-616页

作者： Daming Zhao Yiqing Wang Chung-Li Dong Fanqi Meng Yu-Cheng Huang Qinghua Zhang Lin Gu Lan Liu Shaohua Shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049People’s Republic of China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022People’s Republic of China Department of Physics Tamkang UniversityNew Taipei City 25137TaiwanPeople’s Republic of China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190People’s Republic of China

Despite of suitable band structures for harvesting solar light and driving water redox reactions,polymeric carbon nitride(PCN)has suffered from poor charge transfer ability and sluggish surface reaction kinetics,which limit its photocatalytic activity for water ***,atomically dispersed Zn-coordinated three-dimensional(3D)sponge-like PCN(Zn-PCN)is synthesized through a novel intermediate coordination *** characterizations and theoretical calculations well evidence that Zn single atoms are coordinated and stabilized on PCN in the form of Zn-N_(6) configura-tion featured with an electron-deficient *** an electronic configuration has been demonstrated contributive to promoted electron excitation,accelerated charge separation and transfer as well as reduced water redox *** benefited from the abundant surface active sites derived from the 3D porous structure,Zn-PCN realizes visible-light photocatalysis for overall water splitting with H_(2) and O_(2) simultaneously evolved at a stoichiometric ratio of 2:*** work brings new insights into the design of novel single-atom photocatalysts by deepening the understanding of electronic configurations and reactive sites favorable to excellent photocatalysis for water splitting and related solar energy conversion reactions.

关键词： Zn single atoms Polymeric carbon nitride Overall water splitting Photocatalysis

Waste heat recovery in the coal-fired power generation integrated with post-combustion

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Waste heat recovery in the coal-fired power generation integ...

Electrical engineering and Mechatronics Technology (ICEEMT), IEEE International Conference on

作者： Yali Yang Guiwen Wang Yan Li Yongping Liu Yue Fu Ming Liu Guoneng Jinjie Energy Co. Ltd Yulin China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China

Post combustion systems (PCS) are a viable technology option to reduce carbon dioxide in the electricity production. However, the energy-intensive of PCC precludes its wide scale application. As for the optimization of the post combustion system, there is an optimal inlet temperature of the stripper. By optimizing the parameter of the post combustion system, the energy consumption rate of the post combustion system decreased by 1.4 GJ/t CO 2 under 100% THA compared to the original post combustion system. The needed heat by the stripper shows a fall with the decrease of the unit load ratio. However, the heat changes of the post combustion system decrease with the decrease of the unit load ratio under 90% absorption rate. The efficiency penalty can be as low as 4.1% through waste heat recovery.

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A study on free radical behaviors and reactions in supercritical water using quantum chemical simulation

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Journal of Molecular Liquids 2025年 419卷

作者： Ding, Weijing Takahashi, Osamu Wang, Junying Jin, Hui School of Transportation and Vehicle Engineering Shandong University of Technology Shandong Zi'bo255000 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an710049 China of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima739-8526 Japan

Supercritical water (SCW) gasification is one of clean and efficient utilization way of biomass, other organic matters or coal for hydrogen production, in which radical reactions studies in SCW are limited but crucial. Density-functional tight-binding (DFTB) molecular simulation is one of efficient and convenient approaches to investigate these microscopic processes. Therefore, free radical reactions in severe SCW environment were investigated via DFTB calculations in this work. The results showed that the order of the free radicals containing bond cleavages reacted in SCW environment was ·OH, ·CH, ·CH2, ·HO2, ·CH3 and ·C6H5 under the same conditions. The reaction processes of different radicals in SCW were obtained. ·H was the most active free radical of reactions. This work is expected to understand the properties of free radicals in SCW better and explore intrinsic reaction mechanisms, which may provide a theoretical support for accomplishing efficient and low-carbon complete SCW gasification for hydrogen production. © 2024 Elsevier B.V.

关键词： Free radical Gasification Hydrogen production Reaction Supercritical Water (SCW)

Development of a Two-Phase flow Solver with Drift-Flux Model Based on Openfoam: Validation Against Single/Two-Phase and Boiling flow

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SSRN 2024年

作者： Wu, Wenqiang Zhang, Dalin Huang, Tao Du, Peng Zhou, Lei Wang, Bo Deng, Jian Qiu, Zhifang Tian, Wenxi Qiu, Suizheng Su, Guanghui State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Shaanxi Xi’an710049 China Nuclear Power Institute of China 328 Changshun Avenue Chengdu610213 China

Based on the open-source platform OpenFOAM, this paper implements a two-phase flow solver for drift flux models with realistic closure relations. The solver inherits the numerical method from the OpenFOAM framework, adopts the PIMPLE algorithm, and follows its discrete and matrix-solving criteria, focusing on developing a two-phase flow model and constitutive models. The drift velocity model is based on Ishii and his collaborators’ work. The remaining models, such as wall friction, wall heat transfer, interfacial heat and mass transfer, are taken from TRACE Theory Manual. To fulfill the condition of conjugate heat transfer between fluid and solid, a virtual solid heat transfer function is developed under the premise of a single-domain solver. Extensive and successful validation has been conducted involving single-phase, two-phase, and boiling flow heat transfer phenomena by comparing with experimental data or typical system codes, and the two-phase flow solver's success has been demonstrated in several aspects. © 2024, The Authors. All rights reserved.

关键词： Two phase flow

Characteristics and Prediction Model of Co-Pyrolysis of Sewage Sludge and Camellia Seed Shell

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SSRN 2022年

作者： Wang, Bo Liu, Yinhe Guan, Yu Feng, Yiwei Pan, Hejitian State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi’an710049 China

Tar is an undesired product in the process of sewage sludge pyrolysis, which affects the normal operation of the equipment. In this paper, the characteristics of co-pyrolysis of sewage sludge and camellia seed shell for tar reduction and syngas production were explored. The content and composition of tar and pyrolysis gas co-pyrolyzed with different proportions of sewage sludge (JAS) and camellia seed shell samples (CSS) were studied. The weight loss characteristics of the samples were studied by thermogravimetric experiment, and the synergistic effects of different stages were analyzed. The performances of back propagation (BP) neural network and particle swarm optimization-back propagation neural network (PSO-BP) in reflecting the nonlinear relationship between temperature, mixing ratio, heating rate and remaining weight were compared. The results show that the tar yield was the lowest when 40JAS60CSS was pyrolyzed, which could alleviate the serious problems caused by the tar. Compared with the JAS single pyrolysis, the co-pyrolysis of JAS and CSS improved the content of PAHs and reduced the content of aliphatic hydrocarbons in the tar. The inhibition and promotion effects of co-pyrolysis would be transformed into each other with the progress of the pyrolysis, and the transformations were concentrated in the S 2 stage where the weight loss of the sample is the largest. The constructed PSO-BP-30 model contained two hidden layers, each with 12 neurons, which accurately reflected the nonlinear relationship between the temperature, mixing ratio, heating rate and residual weight. © 2022, The Authors. All rights reserved.

关键词： Pyrolysis

Integrated Co2 Capture and Conversion by Three-Step Chemical Looping Dry Reforming of Methane

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SSRN 2025年

作者： Liu, Yunlian Liu, Mingkai Shen, Yuanhui Li, Yang Gai, Zhongrui Zhang, Ruqi Pan, Ying Jin, Hongguang Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China University of Chinese Academy of Sciences Beijing100049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

The integrated CO2 capture and conversion (ICCC) has emerged as a promising and cost-effective pathway for achieving carbon neutrality. However, limited energy-efficient pathways and durable materials for ICCC systems remains challenging. This study proposes a novel approach that synergistically integrates CO2 capture and conversion through a unified chemical framework. The method employs Li-based sorbents for CO2 capture, coupled with CH4-driven sorbent regeneration that is seamlessly integrated with chemical looping dry reforming of methane (CLDRM), enabling in-situ CO2 conversion. By coupling sorbent regeneration with CLDRM, this system enhances decarbonation kinetics through Le Chatelier's principle via continuous CO2 conversion. One-step calcination synthesized Li-based sorbents particles exhibit stable CO2 capture capacity of 5.25 mmol·g-1 within 15 min per cycle, maintaining 7.5-15% operational efficiency over 40 cycles at 600 ℃. In CLDRM, hydrogen radicals from CH4 dissociation promote the conversion of CO2 to intermediates, lowering the apparent activation energy of sorbents regeneration by 29.2%. Through systematic optimization in a fixed-bed reactor, we achieved 90% CO2 uptake and 85% CH4 conversion, with syngas production rates reaching 13.71 mL·min-1·g-1. Notably, the H2/CO molar ratio in syngas stabilizes ~1.6, aligns with iron-based Fischer-Tropsch and methanol synthesis to produce valuable fuels. This integrated system maintains >80% syngas purity with © 2025, The Authors. All rights reserved.

关键词： Activation energy