Numerical analysis of multiphase flow in chemical looping reforming process for hydrogen production and CO2 capture

Chavda, Akash; Mehta, Pranav; Harichandan, Atal Bihari

doi:10.1007/s42757-021-0105-7

Cited by 26 publications

(7 citation statements)

References 49 publications

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“…It can achieve superior efficiency and significantly reduce the pollutants generated in the traditional gasification and combustion process. , For the gas–solid reactive flows in the SCWG reactors, the surface material of coal or biomass particles is heated and gasified to form a mass flow that is perpendicular to the particle surface and reacts with the surrounding fluid. The mass exchange between particles and surrounding fluid is called Stefan flow, and the momentum, mass transfer, heat transfer, and chemical reactions between particles and fluid are coupled and affected by Stefan flow, making the particle–fluid–particle interactions more complicated. − The impact of Stefan flow on the gas–solid particle reacting flow is further reflected in hydrodynamic behavior and reaction efficiency. − In the reactor, the drag coefficient ( Cd ) and Nusselt number ( Nu ) are two crucial characteristics of particle force and heat transfer efficiency. , Pioneer scholars’ in-depth research and fitted valuable empirical formulas for inert particles in the cold environment can effectively guide industrial production. , However, the previous empirical formulas of the inert particles are no longer applicable for the reactive particles in the high-temperature and reactive environment, and a thorough analysis and complete understanding of the particle–SCW–particle interaction combined with the influence of the Stefan flow, such as heat transfer and flow characteristics, are urgently needed for the scale-up, design, and optimization of the reactor for industrial application.…”

Section: Introductionmentioning

confidence: 99%

“…8−12 In the reactor, the drag coefficient (Cd) and Nusselt number (Nu) are two crucial characteristics of particle force and heat transfer efficiency. 13,14 Pioneer scholars' in-depth research and fitted valuable empirical formulas for inert particles in the cold environment can effectively guide industrial production. 15,16 However, the previous empirical formulas of the inert particles are no longer applicable for the reactive particles in the hightemperature and reactive environment, and a thorough analysis and complete understanding of the particle−SCW−particle interaction combined with the influence of the Stefan flow, such as heat transfer and flow characteristics, are urgently needed for the scale-up, design, and optimization of the reactor for industrial application.…”

Section: Introductionmentioning

confidence: 99%

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Direct Numerical Simulation of Fluid Flow and Heat Transfer of a Reactive Particle Layer with Stefan Flow in Supercritical Water

Wang

Jin

2023

Ind. Eng. Chem. Res.

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Supercritical water gasification is an efficient and clean way of energy conversion. The research on different scales, such as the system, reactor, and particle, has different temporal and spatial significance. A study on particle−particle and particle− fluid−particle interaction on the particle scale has a fundamental guiding value for revealing gasification performance on the reactor scale. Reactive particles such as coal are pyrolyzed and gasified in a high-temperature and high-pressure reactor to form Stefan flow, which affects the mass, momentum, and energy transfer between particles and supercritical water. In this paper, a particle-resolved direct numerical simulation study of a reactive particle layer in supercritical water is carried out to investigate the effect of different particle layer solid holdups and Stefan flow intensities and distributions on the flow and heat transfer process between the particle layer and supercritical water. This work analyzes the pressure and friction drag coefficients to which the particles are subjected and specifies the flow, velocity, and temperature distribution inside and around the particle layer. The results show that the drag coefficient and Nusselt number of particles in the particle layer decrease gradually along the flow direction, and the presence of particle Stefan flow further reduces the drag force and Nusselt number of particles. With the increasing solid holdup of the particle layer, the particle−fluid−particle interaction becomes more intense, and the effect of Stefan flow cannot be negligible.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Direct Numerical Simulation of Fluid Flow and Heat Transfer of a Reactive Particle Layer with Stefan Flow in Supercritical Water

Wang

Jin

2023

Ind. Eng. Chem. Res.

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“…The Eulerian–Eulerian and Eulerian–Lagrangian methods are proposed to simulate dense multiphase flow. In the Eulerian–Eulerian method, particles are treated as continuum and solved in the Eulerian manner, just like fluid. , Via this method, Cai et al studied the hydrodynamics of a binary mixture in a supercritical carbon dioxide fluidized bed. Xie et al studied the mixing/segregation property with various gas velocity and size ratio of binary mixtures in a pilot-scale fluidized bed.…”

Section: Introductionmentioning

confidence: 99%

Particle-Scale Simulation Study of Size-Induced Segregation Characteristics of Binary Particles in a Liquid–Solid Fluidized Bed

Sun

Yang

Bao

et al. 2023

Ind. Eng. Chem. Res.

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The presence of multiple solid particles in a fluidized bed is widespread and has a significant impact on the bed hydrodynamics and heat/mass transfer. In the present work, the mixing and segregation process of premixed binary particles in a liquid–solid fluidized bed is numerically investigated via the computational fluid dynamics-discrete element method (CFD-DEM). In this method, the particles are assumed to be spherical, and their interactions and collisions are calculated using a soft-sphere model. The bed expansion height, pressure drop, and pressure distribution profile obtained by this model are well validated with experimental data. The aim of this study is to investigate particle-level information (e.g., particle velocity, dispersion coefficient and force) during the segregation process and the effect of the particle size ratio and fluidization velocity on them. The results show that particle velocity has similar distribution with the particle dispersion coefficient (D p). During the initial stage, small particles experience stronger interphase momentum exchange and thus have a higher velocity and D p. Enlarging the particle size ratio from 2 to 4, the radial particle D p and velocity increase while the axial ones decrease, indicating the enhancement of interphase momentum change along the radial direction. Increasing the liquid velocity from 0.140 to 0.170 m/s, the segregation index increases from 34.8% to 69.9%. The numerical results can provide valuable guidance for the optimization design of such apparatus in chemical operations, helping to enhance the efficiency and performance.

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“…Hydrogen is a clean energy carrier that has good application prospects in clean combustion, fuel cells, and other aspects. [1][2][3] The wide application of hydrogen is expected to alleviate the greenhouse effect and meet future energy demands. [4][5][6] Nuclear energy enables large-scale hydrogen production with essentially zero carbon emissions; thus, nuclear hydrogen production is considered indispensable for sustainable hydrogen supplies.…”

Section: Introductionmentioning

confidence: 99%

“…Hydrogen is a clean energy carrier that has good application prospects in clean combustion, fuel cells, and other aspects 1‐3 . The wide application of hydrogen is expected to alleviate the greenhouse effect and meet future energy demands 4‐6 .…”

Section: Introductionmentioning

confidence: 99%

Analysis of internal heat exchange network and hydrogen production efficiency of iodine–sulfur cycle for nuclear hydrogen production

Peng

et al. 2022

Intl J of Energy Research

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Summary Nuclear energy enables large‐scale carbon‐free hydrogen production, and the coupling of the very‐high‐temperature gas‐cooled reactor and iodine–sulfur (IS) cycle has the potential to achieve efficient hydrogen production. This study develops the flowsheet of IS process, performs process simulation, designs the internal heat exchange network using pinch point technology, and discusses the thermal efficiency of hydrogen production in detail. The results show that if all heat released by heat exchangers in H2SO4 and HI sections can be fully recovered and utilized, the upper bound of the thermal efficiency of the IS process is 51.9%. The pinch point temperature difference has little impact on the performance of the heat exchange network of the H2SO4 section, but greatly influences the performance of the heat exchange network of the HI section. When the pinch point temperature difference is 5°C to 20°C, the input heat duties required by the H2SO4 and HI sections are reduced by 23.9% to 25.0% and 20.8% to 50.8%, respectively, compared with those without heat exchange networks. After designing the heat exchange network, considering the recovery and utilization of a portion of waste heat, a more realistic hydrogen production efficiency of 30.0% to 37.1% corresponding to the pinch point temperature difference of 5°C to 20°C is given. Highlights Process simulation of IS cycle is conducted to analyze its energy consumption. Internal heat exchange network is designed using pinch point technology. Network performance is studied at different pinch point temperature differences. Thermal efficiency of hydrogen production is discussed in detail.

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Numerical analysis of multiphase flow in chemical looping reforming process for hydrogen production and CO2 capture

Cited by 26 publications

References 49 publications

Direct Numerical Simulation of Fluid Flow and Heat Transfer of a Reactive Particle Layer with Stefan Flow in Supercritical Water

Direct Numerical Simulation of Fluid Flow and Heat Transfer of a Reactive Particle Layer with Stefan Flow in Supercritical Water

Particle-Scale Simulation Study of Size-Induced Segregation Characteristics of Binary Particles in a Liquid–Solid Fluidized Bed

Analysis of internal heat exchange network and hydrogen production efficiency of iodine–sulfur cycle for nuclear hydrogen production

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