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Thermodynamic Analysis on Supercritical Water Gasification of Oily Sludge Using a Continuous Two-Step Method

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SSRN 2024年

作者： Wang, Gaoyun Zhang, Chenghao Zhao, Qiuyang Gao, Yunbo Jin, Hui Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University No. 28 Xianning West Road Xi’an710049 China Technical Inspection Center Sinopec Shengli Oilfield Company Dongying257000 China

A large amount of oily sludge is produced every year around the world and the traditional treatment techniques for oily sludge have deficiencies of incomplete processing and high energy consumption. Supercritical water gasification (SCWG) technology can cleanly convert oily sludge into hydrogen-rich gas and does not require an energy-consuming drying process. This work constructed the desorption-gasification two-step SCWG system based on the previous experimental study and investigated the influences of feed concentration, gasification temperature and sludge compositions on the energy efficiency and exergy efficiency of the system. The results showed that the two-step system had higher energy efficiency and exergy efficiency, as well as better adaptability to various sludge compositions under maintaining high efficiency conditions. The energy efficiency and exergy efficiency of the two-step system were 61.2% and 45.3% respectively under the gasification temperature of 600 ℃ and the feed concentration of 100wt%, which were 91.95% and 93.67% higher than those of the single-step system. Additionally, the desorption unit of two-step system operated at lower temperature, resulting in decreased use of high-temperature resistant materials and reduced economic costs. This research provides valuable insights into the construction and optimization of two-step SCWG of oily sludge. © 2024, The Authors. All rights reserved.

关键词： Desorption

Experimental Study and Theoretical Development of Liquid Entrainment in T-Junction with Double Inlets and Single Inlet of Gas Phase

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SSRN 2023年

作者： Li, Kepiao Shi, Yanggen Zhang, Kui Tian, Wenxi Qiu, Suizheng State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China School of Nuclear Science and Technology Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology Xi'an Jiaotong University Xi’an710049 China

The liquid phase entrainment through vertical-up branch had been analyzed through scaled and full size of experiment since ADS-4 (the fourth-stage Automatic Depressurization System) valve adopted in advanced PWR (Pressurized Water Reactor). Most of the existed studies focus on the single inlet of gas whereas steam may flow from two sides of the T-junction during the blowdown of primary system. Hence the experimental study on liquid entrainment with double end inlets are carried out. The data on the onset of entrainment (OLE) turns out that double end inlets show small difference with single inlet, whereas the entrainment rate research have great difference with single inlet and there is more than 50% error between the data and existing theoretical models. According to the visible flow phenomenon and flow instability, a new entrainment rate model was proposed which can well predict the double-end inlets and single-inlet entrainment phenomenon with the error within ±20%. © 2023, The Authors. All rights reserved.

关键词： Pressurized water reactors

X-ray computed tomography (XCT) study of jetting in a fluidized bed: Effects of two-component fluidization

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Particuology 2025年 102卷 264-274页

作者： Xiang, Zhong Chen, Xi Liu, Shuguang Heindel, Theodore J. School of Energy and Environment Southeast University Nanjing210096 China State Key Laboratory of Low-carbon Smart Coal-fired Power Generation and Ultra-clean Emission Southeast University Nanjing210096 China Center for Multiphase Flow Research and Education and Department of Mechanical Engineering Iowa State University AmesIA50011 United States

Fluidization of non-spherical particles is commonly found in the biomass and solid waste processing industry, and the jetting characteristic above the aeration plate is critical to the fluidization performance of these particles. In this study, cylindrical particles are used as typical non-spherical particles and co-fluidized with small bed material particles. X-ray computed tomography (XCT) is used to reconstruct the 3D structure of the aeration plate region, allowing for the identification of individual aeration jets. The effects of jet velocity (Uj), cylindrical particle mass fraction (ω), cylindrical particle density (ρi), and the cylindrical particle sphericity () on jet shape and volume are investigated. The experimental results indicate that decreasing the cylindrical particle mass fraction (ω) and particle density (ρi) increases the jet length (L), maximum jet diameter (D), and maximum jet volume (V), but have little effect on the jet half angle (θ). The cylindrical particle density (ρi) is the most sensitive factor for jet shape, while the effect of cylinder particle sphericity () on jet shape is insignificant. A correlation of jet length (L) in a two-component fluidized bed with cylindrical particles and bed material is proposed based on all the experimental results. © 2025 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences

关键词： Binary fluidized bed Cylindrical particle fluidization Jetting X-ray computed tomography

Multi-Objective optimization of oil–gas cyclone separators considering liquid storage in the tank bottom

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Separation and Purification Technology 2025年 374卷

作者： Wang, Lingzi Du, Wei Liu, Ruiyi Feng, Jianmei Peng, Xueyuan Cao, Feng School of Energy and Power Engineering Xi'an Jiaotong University Shaanxi Xi'an710049 China The First Gas Plant of PetroChina Changqing Oilfield Company Shaanxi Jingbian718500 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

As an efficient separation device, the gas–liquid cyclone separator has been widely used in oil injection compressor systems. It can effectively reduce the oil content in the high-pressure airflow, directly affecting the fuel consumption, operating efficiency, and exhaust quality parameters of compressors, making it crucial to enhance the separator's performance. Given the critical role of geometric configuration in determining cyclone separator efficiency, this study comprehensively considers several influencing factors including the structure parameters. Taguchi method and analysis of variance (ANOVA) were used to quantify the contribution of three factors to the performance percentage of the separator, and the dual-objective optimization of the efficiency and pressure drop of the separator was carried out with the grey correlation analysis method. In the simulation calculation, this paper employs the DPM-to-VOF method coupled with the Euler wall film (EWF) to simulate the oil droplet particle separation process, featuring model transformation capabilities under specified conditions. The investigation culminates in the development of a parametric-performance prediction model and establishes optimal operational parameters for cyclone separators: the inlet velocity (vin) should be set at 24.49 m/s, the height of the inner cylinder of the separator tank (Ht) should be 1.2 times the diameter, and the buffer height between the inner cylinder and the liquid surface (Hm) should be 0.9 times the diameter. © 2025

关键词： Cyclone separators

Editor, Applied Energy Paper Entitled: "Industrialized Bimetallic Nano Oxygen Carrier for Dual-Stage Hydrogen Production from Mid-Temperature Chemical Looping Reforming"

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SSRN 2024年

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

Chemical looping methane reforming has emerged as a promising avenue to produce blue hydrogen. Among the various oxygen carriers investigated for this process, Fe2O3 and NiO have garnered significant attention due to their affordability and favorable thermodynamic properties. Usually, such oxygen carriers had satisfactory H2 yields only in the oxidation stage with temperatures over 800 °C. This limitation poses challenges for industrial reactor design and product gas separation. In this study, we present a nanoscale Fe/Ni bimetallic oxygen carrier for dual-stage hydrogen generation from mid-temperature chemical looping methane reforming. The lab-scale oxygen carrier can produce H2 in both the reduction and the oxidation steps, reaching 75% overall H2 purity while reducing the temperature to 500-600 °C. Moreover, the 10-kg scale oxygen carrier achieved >90% CH4 conversion, >78% H2 purity and 2.8-3.5 H2 molecules produced per CH4 molecule. Made into beads, the 10-kg scale oxygen carrier still maintained an outlet H2 purity of >70% with redox stability over 150 cycles. These findings contribute to the advancement of chemical looping methane reforming for blue hydrogen production and supply. © 2024, The Authors. All rights reserved.

关键词： Hydrogen production

Applying multi-scale simulations to materials research of nuclear fuels:A review

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Materials Reports(Energy) 2021年第3期1卷 64-80页

作者： Chunyang Wen Di Yun Xinfu He Yong Xin Wenjie Li Zhipeng Sun School of Nuclear Science and Technology Xi'an Jiaotong UniversityXi'an710049China State Key Laboratory of Multiphase Flow Xi'an Jiaotong UniversityXi'an710049China China Institute of Atomic Energy Beijing102413China Key Laboratory of Nuclear Reactor System Design Technology Nuclear Power Institute of ChinaChengdu610213China

Computational simulation is an important technical means in research of nuclear fuel *** nuclear fuel issues are inherently multi-scopic,it is imperative to study them with multi-scale simulation *** present,the development of multi-scale simulation for nuclear fuel materials calls for a more systematic approach,in which lies the main purpose of this *** most important thing in multi-scale simulation is to accurately formulate the goals to be achieved and the types of methods to be *** this regard,we first summarize the basic principles and applicability of the simulation methods which are commonly used in nuclear fuel research and are based on different scales ranging from micro to macro,***-Principles(FP),Molecular Dynamics(MD),Kinetic Monte Carlo(KMC),Phase Field(PF),Rate Theory(RT),and Finite Element Method(FEM).And then we discuss the major material issues in this field,also ranging from micro-scale to macro-scale and covering both pellets and claddings,with emphasis on what simulation method would be most suitable for solving each of the ***,we give our prospective analysis and understanding about the feasible ways of multi-scale integration and relevant handicaps and challenges.

关键词： Computational simulation Nuclear fuel Multi-scale modeling Irradiation behavior

From Lab to Industry: Scaling-Up Fe-Ni Bimetallic Nano Oxygen Carrier for Mid-Temperature Methane Chemical Looping Reforming

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SSRN 2024年

Chemical looping methane reforming has emerged as a promising avenue to produce blue hydrogen. Currently, the satisfactory CH4 conversion and H2 productivity are usually seen under temperatures above 800 °C. Such temperature requirement poses challenges for industrial reactor design and product gas separation. Investigated widely in chemical looping, bimetallic oxygen carrier has both catalytic and oxygen releasing functions, thus expected to realize both lower reaction temperature and high performance. In this study, we present a nanoscale Fe-Ni bimetallic oxygen carrier for mid-temperature chemical looping methane reforming which can be implemented at large scale. By virtue of a synergy from nanoscale Fe-Ni dispersion, all oxygen carriers from lab-scale to 10-kg scale can operate at 500-600 °C. The lab-scale oxygen carrier was found to convert >90% CH4, produce 3.5 H2 per CH4 molecule with 80-82% overall H2 purity at 575-600 °C. Following the proposed large-scale synthesis workflow, we acquired the 10-kg scale oxygen carrier powder with 70% with 2.8 H2 from per CH4 molecule. The 10-kg powders and beads both persisted phase, morphology and redox stability over 150 cycles. Further explorations revealed the similarity in structure and reaction performance between the lab-scale and 10-kg scale powders, and differences in reaction dynamics between the 10-kg powder and beads. These findings contribute to the mid-temperature chemical looping methane reforming by bridging laboratory practices and industrial application. © 2024, The Authors. All rights reserved.

关键词： Powders

Optimization of Heliostat Fields Using Advanced Particle Swarm Optimization (APSO) 4

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Optimization of Heliostat Fields Using Advanced Particle Swa...

4th IEEE International Conference on Renewable Energy and Power Engineering, REPE 2021

作者： Rizvi, Arslan A. Yang, Dong Khan, Talha Ali Xi'An Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an710049 China University of Europe for Applied Sciences Department of Data Science Potsdam Germany

ISBN: (纸本)9781665443715

Optical losses account for 40% of all the losses in a central receiver system. These optical losses occur due to factors like shading, blocking, atmospheric attenuation, spillage, cosine loss, and mirror reflectivity. These factors are collectively represented using a single factor known as optical efficiency. There exists a tradeoff among these factors. The unavoidable optical loss can be minimized by optimizing the positions of heliostats in a strategic manner. An advanced particle swarm algorithm is used to optimize the position of heliostats around a dense radial staggered field. An efficiency map of the heliostat field is generated. Using instantaneous optical efficiency as an objective function, a single objective optimization is performed using 30 particles and 2 dimensions (each dimension representing an optimization variable). The results highlight the areas in the heliostat field with the highest losses associated with different components of optical efficiency and their solution. The instantaneous efficiency increases by 1.5% after optimization. © 2021 IEEE.

关键词： Particle swarm optimization (PSO)

Study on the Dynamic Characteristics, Control Strategy and Load Variation Rate of the Concentrated Solar Power Plant

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SSRN 2023年

作者： Li, Gen Du, Guanghan Liu, Guixiu School of Electric Power Engineering South China University of Technology Guangzhou510641 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

With more and more wind power and photovoltaic power connected to the electric power system, it has brought great challenges to the stability of the power grid. Concentrated solar power (CSP) plant as one form of solar power generation can undertake the task of load regulation and frequency regulation in power grid to balance the electricity demand and generation. However, the maximum load variation rate of the CSP plant is not known, which limits sufficient utilization of its advantages. In this study, a dynamic simulation model of the CSP plant was built using the APROS, and the dynamic characteristics were investigated by applying the step disturbances to molten salt flowrate, molten salt temperature, and the opening of steam regulating valve. Based on the results of dynamic characteristics, the control strategies were developed with the consideration of thermal storage in system and the feedforward signal of set load and load variation rate. Then, the maximum load increase and reduction rates within different load ranges were studied. The results indicated that the steam regulating valve could be used to control turbine power, molten salt flowrate could be used to control steam pressure, and the molten salt temperature could be used to control steam temperature. The designed control system could effectively follow the load variation, with the load deviation less than 0.3 MW and the steam temperature deviation less than 1.2 ℃ in the condition of load variation rate at 3% Pe·min-1. The maximum load increase and reduction rates were 11.57% Pe·min-1 and 8.94% Pe·min-1 within the load range of 75%THA-100%THA, and they were 10.42% Pe·min-1 and 7.46% Pe·min-1 within the load range of 50%THA-75%THA, respectively. © 2023, The Authors. All rights reserved.

关键词： Concentrated solar power