A Novel Solar Expanding-Vortex Particle Reactor: Influence of Vortex Structure on Particle Residence Times and Trajectories

Chinnici, Alfonso; Arjomandi, Maziar; Tian, Zhao Feng; Zhao, Litao; Nathan, Graham J.

doi:10.1016/j.solener.2015.08.017

Cited by 56 publications

(20 citation statements)

References 43 publications

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“…This enhancement of heat transfer and reaction kinetics was for example experimentally shown by one of the earlier studies by Maag et al where micron size carbon particles were fed to the main CH4 feedstock [12]. Another particle study numerically determined the optimum flow configuration for a solar vortex reactor aimed at maximizing residence time of the particles [13]. Other similar studies in the field evaluated the performance of metallic and carbonaceous catalysts on the solar decomposition of methane [14].…”

Section: Introductionmentioning

confidence: 72%

“…Carbon deposition has also been experimentally observed in different methane cracking reactor types such as the ones found in Ref. [13] and Ref. [16].…”

Section: Introductionmentioning

confidence: 91%

“…In their numerical study on a solar vortex reactor Chinnici et al presented two aerodynamic mechanisms in an attempt to address window deposition in solar expanding-vortex receiver-reactors [13]. Outcome of their particle-tracking study yielded ideal geometric and flow configuration parameters with respect to mitigation of particle deposition on the window.…”

Section: Introductionmentioning

confidence: 99%

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A numerical study on particle tracking and heat transfer enhancement in a solar cavity receiver

Ophoff

Özalp

Moens

2020

Applied Thermal Engineering

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The thermochemical dissociation of natural gas into hydrogen and carbon involves the presence of solid phase carbon particles. In addition to the produced carbon, carbon particles can be seeded to the process as a catalyst which act both as a heat transfer enhancing medium and nucleation site for the dissociation reaction. However, presence of discrete phase particles imposes various challenges such as deposition on solar reactor walls and windows, and clogging of the exhaust. Meticulous reactor-receiver design optimization is therefore required and is presented in this study. The Discrete Phase Model (DPM) was implemented in a numerical CFD model to track injected carbon particles in a Lagrangian framework.Validation of the model was done with respect to available experimental data and showed similar deposition phenomena on the reactor window. A parametric design study was performed taking into account flow rates, particle size, particle loading and receiver geometry. Use of a finer particle size distribution demonstrated the ability of the flow to entrain more particles to the exhaust and reduce deposition on the bottom wall of the cavity. Three design iterations on an existing 1 kW solar cavity receiver were proposed, depicting an increase of at least 6.5% on the outlet gas temperature and 4% on the overall average gas temperature within the receiver. Results of this study highlighted the importance of flow configuration, flow parameters and particle size on the deposition and heat transfer inside solar cavity receivers. Outcome of this study can serve as a reference for solar reactor design involving presence of particulate media.

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Section: Introductionmentioning

confidence: 72%

“…Carbon deposition has also been experimentally observed in different methane cracking reactor types such as the ones found in Ref. [13] and Ref. [16].…”

Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

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A numerical study on particle tracking and heat transfer enhancement in a solar cavity receiver

Ophoff

Özalp

Moens

2020

Applied Thermal Engineering

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“…To elucidate the fundamental transport mechanisms and guide the optimization for an improved process performance, we have developed a numerical heat transfer and fluid flow model of the solar reactor. Previous pertinent modeling studies include heat transfer analysis of a suspension of reacting carbonaceous particles for directly irradiated [21][22][23] and indirectly irradiated flows [24], and aerodynamic analysis for a directly irradiated vortex flow [25,26]. Still missing is a model that captures in detail both heat transfer and fluid-flow characteristics of an indirectly irradiated solar reactor for the gasification of a particulate carbonaceous flow at high pressures, including coupled radiative transfer and chemical kinetics with shrinking particles.…”

Section: Introductionmentioning

confidence: 99%

A Pressurized High-Flux Solar Reactor for the Thermochemical Gasification of Charcoal Slurry—Two-Phase Flow and Heat Transfer Analysis

Müller

Steinfeld

2019

Journal of Heat Transfer

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A pressurized solar reactor for effecting the thermochemical gasification of carbonaceous particles driven by concentrated solar energy is modeled by means of a reacting two-phase flow. The governing mass, momentum, and energy conservation equations are formulated and solved numerically by finite volume computational fluid dynamics (CFD) coupled to a Monte Carlo radiation solver for a nongray absorbing, emitting, and scattering participating medium. Implemented are Langmuir–Hinshelwood kinetic rate expressions and size-dependent properties for charcoal particles undergoing shrinkage as gasification progresses. Validation is accomplished by comparing the numerically calculated data with the experimentally measured temperatures in the range 1283–1546 K, chemical conversions in the range 32–94%, and syngas product H2:CO and CO2:CO molar ratios obtained from testing a 3 kW solar reactor prototype with up to 3718 suns concentrated radiation. The simulation model is applied to identify the predominant heat transfer mechanisms and to analyze the effect of the solar rector's geometry and operational parameters (namely: carbon feeding rate, inert gas flowrate, solar concentration ratio, and total pressure) on the solar reactor's performance indicators given by the carbon molar conversion and the solar-to-fuel energy efficiency. Under optimal conditions, these can reach 94% and 40%, respectively.

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“…(1), i.e., higher pressures shift the thermodynamic equilibrium composition to higher temperatures. The intersection around T reactor = 1120 °C points out to non-linear competing effects as X C either decreases or increases with pressure at above or below that temperature, presumably due to change in the swirl number which affects the actual residence time[29].…”

mentioning

confidence: 98%

A pressurized high-flux solar reactor for the efficient thermochemical gasification of carbonaceous feedstock

Müller

Poživil

Eyk

et al. 2017

Fuel

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We report on the design and first-ever experimental demonstration of a 3 kW pressurized solar reactor for thermochemically converting carbonaceous feedstocks into gaseous fuels. It uses a windowless SiC cavity to efficiently absorb and transfer concentrated solar radiation to an annular gas-particle vortex flow created by injecting tangentially a charcoal/water slurry at high pressures. Experiments were carried out in a high-flux solar simulator under a solar concentration ratio equivalent to 3718 suns. For slurry feeding rates in the range 0.42-1.26 g/min, H 2 O:C molar ratios in the range 1.48-1.98, and absolute reactor pressures in the range 1-6 bar, the nominal reactor temperature was between 1009 and 1273 °C yielding high-quality syngas with a carbon conversion up to 94% within residence times of less than 5

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A Novel Solar Expanding-Vortex Particle Reactor: Influence of Vortex Structure on Particle Residence Times and Trajectories

Cited by 56 publications

References 43 publications

A numerical study on particle tracking and heat transfer enhancement in a solar cavity receiver

A numerical study on particle tracking and heat transfer enhancement in a solar cavity receiver

A Pressurized High-Flux Solar Reactor for the Thermochemical Gasification of Charcoal Slurry—Two-Phase Flow and Heat Transfer Analysis

A pressurized high-flux solar reactor for the efficient thermochemical gasification of carbonaceous feedstock

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