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Three-dimensional dynamic characterization of square-nosed slugging phenomena in a fluidized bed

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Particuology 2022年第8期20卷 35-46页

作者： Yaswanth Pottimurthy Dawei Wang Cody Park Shalin Patil Andrew Tong liang-shih fan Willam G.Lowrie Department of Chermical and Biomolecular Engineering.The Ohio State Univrsity ColumbusOH 43210USA

Slugging represents one of the major regimes in fluidization,which occurs in small diameter beds with large bed height-to-diameter ratio or in large diameter beds with internals that resemble multiple small diameter fluidized *** types include round-nosed slug,wall slug and square nosed *** of the slugs have been mainly focused on round-nosed or wall slugs known as half *** occurring in Geldart group A particle *** square-nosed slug typically occurring for Geldart group D particles appears to be regarded as simple in its *** Electrical Capacitance Volume Tomogra phy(ECVT)imaging of the square-nosed slugging phenomena conducted in this study reveals *** is the structure of the square nosed slug is,in fact,complex,particularly with respect to its dynamic variation in *** *** study examines experimentally the hydrodynamic character-istics of the square-nosed fluidization ***,simultaneous measurements from multiple ECVT sensors provide non-inv asive,continuous,*** imaging of the entire flow region of the slugging bed and hence enabling the dynamic characterization of the evolution of the *** analysis of the 3D images reconstructed for real time gas-solid volume fraction profile of the slugging fluidized bed indicates that there are three different *** bottom fluidization zone,the gas slug zone,and the solid slug zone,co-existing in the *** three zones present different hydrodynamic characteristics during the slug *** is found that varying the gas velocity of the slugging bed mainly varies the maximum length of the gas slug zone,while it only has a minor effect on the lengths of the bottom fluidization zone and solid slug *** also has an insignificant efect on the solid volume fraction of the three zones.

关键词： Gas-solid flow Fluidized bed Square-nosed slugging Electrical Capacitance Volume Tomography

Handbook of Fluidization,Mooson Kwauk,Hongzhong Li

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Particuology 2009年第2期7卷 158-160页

作者： liang-shih fan Department of Chemical and Biomolecular Engineering The Ohio State University United States

Fluidization is an important process technology and is ubiquitously present in the process industry. The phenomena of fluidization also represent one of the most fascinating fluid-particle interactive behaviors in nature that are manifested by complex, intertwining science and engineering principles. Even though it is a centuries old practice, pursuit of the fundamental understanding of fluidization has its origins in the 1940s. Since the 1960s, fluidization has been a vibrant field for fluid mechanics, particle mechanics, as well as modeling and computation. From the historical perspective, Professor Mooson Kwauk and Professor Richard Wilhelm＇s 1948 article ＂Fluidization of Solid Particles,＂ is proved to be a pioneering work that sets a stage for subsequent fundamental studies in the characteristics of fluidization. As the field has evolved over the last six decades, Professor Kwauk has been a leader of fluidization research in China and the world,

关键词： Handbook of Fluidization Mooson Kwauk Hongzhong Li

FLOW DYNAMICS OF GAS-SOLID FLUIDIZED BEDS WITH EVAPORATIVE LIQUID INJECTION

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China Particuology 2006年第1期4卷 1-8页

作者： W. Warsito liang-shih fan Department of Chemical and Biomolecular Engineering The Ohio State University 140 West 19th Avenue Columbus OH 43210 USA

The electrical capacitance tomography （ECT） with neural network multi-criteria image reconstruction technique （NN-MOIRT） is developed for real time imaging of a gas-solid fluidized bed using FCC particles with evaporative liquid injection. Some aspects of the fundamental characteristics of the gas-solid flow with evaporative liquid injection including real time and time averaged cross-sectional solids concentration distributions, the cross-sectional solids concentration fluctuations and the quasi-3D flow structures are studied. A two-region model and a direct image calculation are proposed to describe the dynamic behavior in both the bubble/void phase and the emulsion phase based on the tomographic images. Comparisons are made between the fundamental behaviors of the gas-solid flows with and without evaporative liquid injection for various gas velocities ranging from bubbling to turbulent fluidization regimes. Significant differences are observed in the behavior of the gas-solid flow with the evaporative liquid injection compared to the fluidized bed without liquid injection.

关键词： gas-solid fluidized bed evaporative liquid injection electrical capacitance tomography real time imaging

Chemical Looping Clean Energy Technology Toward a Low-Carbon Future

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Engineering 2023年第10期29卷 42-44页

作者： Zhuo Cheng Anuj Joshi liang-shih fan Department of Chemical and Biomolecular Engineering The Ohio State UniversityColumbusOH 43210USA

*** and opportunities for carbon neutrality Global carbon emissions,primarily from the use of fossil fuels,have dramatically risen since the industrial revolution,leading to an increase in global temperature and negatively impacting Earth’s *** the coronavirus disease 2019(COVID-19)pandemic’s economic downturn may have temporarily reduced emissions.

关键词： Clean emissions primarily

New Insight into the Development of Oxygen Carrier Materials for Chemical Looping Systems

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Engineering 2018年第3期4卷 343-351页

作者： Zhuo Cheng Lang Qin Jonathan A. fan liang-shih fan William G. Lowrie Department of Chemical and Biomolecular Engineering The Ohio State University Columbus OH 43210 USA Department of Electrical Engineering Ginzton Laboratory Stanford University Stanford CA 94305 USA

Chemical looping combustion （CLC） and chemical looping reforming （CLR） are innovative technologies for clean and efficient hydrocarbon conversion into power, fuels, and chemicals through cyclic redox reac- tions. Metal oxide materials play an essential role in the chemical looping redox processes. During reduc- tion, the oxygen carriers donate the required amount of oxygen ions for hydrocarbon conversion and product synthesis. In the oxidation step, the depleted metal oxide oxygen carriers are replenished with molecular oxygen from the air while heat is released. In recent years, there have been significant advances in oxygen carrier materials for various chemical looping applications. Among these metal oxide materials, iron-based oxygen carriers are attractive due to their high oxygen-carrying capacity, cost ben- efits, and versatility in applications for chemical looping reactions. Their reactivity can also be enhanced via structural design and modification. This review discusses recent advances in the development of oxy- gen carrier materials and the mechanisms of hydrocarbon conversion over these materials. These advances will facilitate the development of oxygen carrier materials for more efficient chemical looping technology applications.

关键词： Chemical looping Oxygen carrier Hydrocarbon conversion Ionic diffusion Mechanism

EFFECT OF NOZZLE fan ANGLE ON SPRAYS IN GAS-SOLID RISER FLOW

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China Particuology 2006年第3期4卷 147-152页

作者： Muhammad M. R. Qureshi Chao Zhu Chao-Hsin Lin liang-shih fan Department of Mechanical Engineering New Jersey Institute of Technology Newark NJ 07102 USA Environmental Control Systems Boeing Commercial Airplanes Group Seattle WA 98124 USA Department of Chemical Engineering Ohio State University Columbus OH 43210 USA

A three-dimensional simulation study is performed for investigating the hydrodynamic behaviors of a cross-flow liquid nitrogen spray injected into an air-fluidized catalytic cracking （FCC） riser of rectangular cross-section. Rectangular nozzles with a fixed aspect ratio but different fan angles are used for the spray feeding. While our numerical simulation reveals a generic three-phase flow structure with strong three-phase interactions under rapid vaporization of sprays, this paper tends to focus on the study of the effect of nozzle fan angle on the spray coverage as well as vapor flux distribution by spray vaporization inside the riser flow. The gas-solid （air-FCC） flow is simulated using the multi-fluid method while the evaporating sprays （liquid nitrogen） are calculated using the Lagrangian trajectory method, with a strong two-way coupling between the Eulerian gas-solid flow and the Lagrangian trajectories of spray. Our simulation shows that the spray coverage is basically dominated by the spray fan angle. The spray fan angle has a very minor effect on spray penetration. The spray vaporization flux per unit area of spray coverage is highly non-linearly distributed along the spray penetration. The convection of gas-solid flow in a riser leads to a significant downward deviation of vapor generated by droplet vaporization, causing a strong recirculating wake region in the immediate downstream area of the spray.

关键词： numerical simulation spray evaporation fan angle circulating fluidized bed

Magnetic resonance studies of jets in a gas-solid fluidised bed

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Particuology 2012年第2期10卷 161-169页

作者： Meenal Pore Thusara C. Chandrasekera Daniel J. Holland Aining Wang Fei Wang Qussai Marashdeh Michael D. Mantle Andrew J. Sederman liang-shih fan Lynn F. Gladden John S. Dennis Department of Chemical Engineering and Biotechnology University of Cambridge Pembroke Street Cambridge CB2 3RA United Kingdom The William G. Lowrie Department of Chemical and Biomolecular Engineering Ohio State University Columbus OH 43210 USA

Magnetic resonance imaging （MRI） has been used to study the behaviour Of jets at the distributor of a 50 mm diameter fluidised bed of 0.5 mm diameter poppy seeds. Two perforated-plate distributors were examined, containing either 10 or 14 holes, each 1 mm diameter. Ultra-fast MR imaging was able to show the transient nature of the upper parts of the jets, where discrete bubbles are formed. Imaging in 3D showed that the central jets were the longest for flow rates below minimum fluidisation. Above minimum fluidisation, the outer jets, nearest the wall of the fluidised bed, arched inward towards the central axis. In this latter case, interpretation of the time-averaged 3D image required the use of ultra-fast MR imaging to identify the approximate height above the distributor at which discrete bubbles were formed. The apparently continuous void extending along the central axis above this height in the time-averaged 3D image was thus identified, using ultra-fast MR imaging, as representing the averaged paths of released bubbles. Time-averaged MR velocity mapping was also used to identify dead zones of stationary particles resting on the distributor between the jets. The dead zones could be observed when the superficial velocity of the gas approached minimum fluidisation, but they were smaller than those observed at lower gas superficial velocity. Comparable images of a single jet through 1.2 mm diameter poppy seeds from MRI and electrical capacitance volume tomography （ECVT） are also demonstrated.

关键词： Fluidised bedMRIECVTJetsDistributor design

Co@C-N as an electronic mediator anchored with Cu2O nanoparticles enables efficient photoreduction of CO2 to CO with nearly 100% selectivity

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Science China Chemistry 2025年

作者： Xingbin Pan Xiuzheng Deng Jingshan fan Jiangchuan Liu Changhai Liu Zhongyu Li Qian liang Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology CNPC-CZU Innovation Alliance School of Petrochemical Engineering Changzhou University School of Materials Science & Engineering Changzhou University

Solar-driven CO2conversion into value-added chemical provides an attractive strategy for sustainable development. However,the enhanced CO2photoreduction performance with target product selectivity remains a major challenge. Here, we develop a novel strategy involving Cu2O nanoparticles in situ grown on the surface of ZIF-67-derived Co@C-N nanocages （CC） to create abundant active sites and appropriate heterointerfaces. A remarkable CO selectivity of 95.7%with a yield of 117.39μmol g-1h-1and an apparent quantum efficiency as high as 1.88%at 420 nm was obtained over CC-60 catalyst in pure water, which was 87.6times higher than that of pure Cu2O. Theoretical calculations and experiments indicated that Co@C-N nanocages as charge mediator not only rapidly trap photogenerated electrons to promote charge separation efficiency, but also regulate the d-band center of Cu atoms to move to the Fermi energy level, thereby optimizing the reaction kinetics to facilitate the highly selective conversion of the key intermediate *CO desorption to CO.

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Natural and human-induced decline and spatio-temporal differentiation of terrestrial water storage over the Lancang-Mekong River Basin

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Journal of Geographical Sciences 2025年第1期35卷 112-138页

作者： CHEN Junxu WANG Yuan ZHAO Zhifang fan Yunjiang LUO Xiaochuan YI Lu FENG Siqi YANG liang Emlyn Yunnan Key Laboratory of Soil Erosion Prevention and Green Development Yunnan University International Joint Research Center for Karstology Yunnan University School of Engineering Westlake University Department of Geography Ludwig Maximilian University of Munich (LMU)

Due to water conflicts and allocation in the Lancang-Mekong River Basin(LMRB), the spatio-temporal differentiation of total water resources and the natural-human influence need to be clarified. This work investigated LMRB's terrestrial water storage anomaly(TWSA) and its spatio-temporal dynamics during 2002–2020. Considering the effects of natural factors and human activities, the respective contributions of climate variability and human activities to terrestrial water storage change(TWSC) were separated. Results showed that:(1) LMRB's TWSA decreased by 0.3158 cm/a.(2) TWSA showed a gradual increase in distribution from southwest of MRB to middle LMRB and from northeast of LRB to middle LMRB. TWSA positively changed in Myanmar while slightly changed in Laos and China. It negatively changed in Vietnam, Thailand and Cambodia.(3) TWSA components decreased in a descending order of soil moisture, groundwater and precipitation.(4) Natural factors had a substantial and spatial differentiated influence on TWSA over the LMRB.(5) Climate variability contributed 79% of TWSC in the LMRB while human activities contributed 21% with an increasing impact after 2008. The TWSC of upstream basin countries was found to be controlled by climate variability while Vietnam and Cambodia's TWSC has been controlled by human activities since 2012.

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