A new correlation for predicting solids concentration in the fully developed zone of circulating fluidized bed risers

Qi, Xin; Zhu, Jesse; Huang, Weixing

doi:10.1016/j.powtec.2008.03.012

Cited by 36 publications

(20 citation statements)

References 20 publications

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“…Under the same gas velocity, with the increase of particle size, the elutriation capacity decreased correspondingly, and the amount of particle elutriated to the annular CS dilute phase was reduced, so the solid circulation rate and the solid fraction of the annular CS dilute phase decreased. Different empirical correlations proposed by different scholars have been used to predict the relationship between the solid fraction of dilute phase and the solid circulation rate [45][46][47][48][49][50][51][52][53] . Taking the solid circulation rate measured in the experiments as the independent variable, the solid fraction of dilute phase was calculated according to these correlations.…”

Section: Effect Of Operational Conditions On Fluidization Characteristicsmentioning

confidence: 99%

“…The average relative errors between the calculated results and the experimental data were big. This is because most of the correlations are applicable to the cases where the gas velocity is bigger than 3 m/s (turbulent or fast bed) or the bed materials belong to Geldart A particles 49,[51][52][53] .…”

Section: Effect Of Operational Conditions On Fluidization Characteristicsmentioning

confidence: 99%

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Cold Model Study of a 1.5 MW_th Circulating Turbulent Fluidized Bed Fuel Reactor in Chemical Looping Combustion

Liu

et al. 2020

Energy Fuels

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A circulating turbulent fluidized bed (CTFB) connected with a riser and an annular carbon stripper (CS) is proposed to be used as a fuel reactor (FR) in chemical looping combustion. The bottom section of the FR is operated under turbulent fluidization regime which can achieve enough solid residence time and enhance the mixing of oxygen carrier with solid fuel. A 1.5 MWth cold model of the FR was designed, constructed and tested in order to investigate the hydrodynamics of solid particles with different size. Three kinds of quartz sands with different particle sizes (d50=122 μm, 249 μm, and 392 μm) were used as bed materials to simulate the oxygen carrier.Continuous operation with reasonable pressure balance was achieved in the cold model. The effects of important variables including gas velocity, static bed height and 2 particle size on the gas-solid hydrodynamics of the FR were measured and discussed.It was found that the transition velocities from bubbling to turbulent fluidization for different particles of d50=122 μm, 249 μm, and 392 μm were measured to be 0.78 m/s, 0.95 m/s and 1.06 m/s respectively, indicating the transition velocity increased with increasing particle size. The solid fraction profile along reactor height and solid circulation rate were affected by gas velocity and static bed height. A modified correlation was proposed to predict the solid fraction of the annular CS dilute phase, and the predicted results agree well with the experimental data under wide range of operational conditions.

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Section: Effect Of Operational Conditions On Fluidization Characteristicsmentioning

confidence: 99%

Section: Effect Of Operational Conditions On Fluidization Characteristicsmentioning

confidence: 99%

Cold Model Study of a 1.5 MW_th Circulating Turbulent Fluidized Bed Fuel Reactor in Chemical Looping Combustion

Liu

et al. 2020

Energy Fuels

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“…This operational parameter influences the heat transfer Blaszczuk, Nowak, & Jagodzik, 2014;Lakatos, Süle, & Mihálykó, 2008), the combustion process (Basu, 2006;Myöhanen & Hyppänen, 2011;Saastamoinen & Tourunen, 2012;Scala & Chirone, 2010), and hydrodynamics (Chalermsinsuwan, Boonprasop, Nimmanterdwong, & Piumsomboon, 2014;Qi, Zhu, & Huang, 2008) in CFB reactors. The complex hydrodynamics and combustion processes occurring inside a CFB boiler are very difficult to model and obtain accurate numerical predictions.…”

Section: Introductionmentioning

confidence: 99%

Simulation of mass balance behavior in a large-scale circulating fluidized bed reactor

2016

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“…Несмотря на то, что результаты моделирования оказались в хорошем соответствии с промышленными экспе-риментами, сама циркуляция и ее влияние на гидродинамическую обстановку в реакторе не входили в задачи этого исследования. То же можно сказать и о результатах работы [7], в которой найдены всесторонние корреляции для лучшего прогнозирования распределения концентрации частиц в зоне полностью развитого слоя в реакторе. Несмотря на то, что эти корреляции хорошо работают в широком диапазоне параметров реактора, взаимное влияние циркуляции и процесса в реакторе не было исследовано.…”

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Influence of gas flow oscillation on the efficiency of particulate solids treatment in a circulating fluidized bed

et al. 2019

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Apparatuses with fluidized bed are widely used in the solid fuel energetic, chemical and other industries. In particular, fluidized bed furnaces play the increasing role for thermo-chemical treatment and burning the solid fuels including bio-fuels. The use of pulsating gas flows is one of the possible ways to intensify the process of gas-particle interaction. However, the efficiency of the way is not always obvious, and new approaches are needed for preliminary estimation of its advantages. The method of mathematical modeling is used to solve the above problem. The model is based on the set of differential equations of a single particle motion in the upstream gas flow with variable with time velocity, and with variable with time particle properties due to this or that thermo-physical or chemical process of gas-particle interaction. The study of influence of the process parameters on its efficiency is done by numerical methods. The model of the effect of oscillations in the gas flow on the efficiency of particle processing in a circulating fluidized bed has been developed. The necessary time for enough particle treatment is compared for different amplitude and frequency of gas flow oscillation. The most considerable gain in time is being reached for the strong dependence of the reaction rate constant on the velocity of flow around the particle. In this case the optimum frequency of oscillations exists that give the maximum gain in time. The growth of the amplitude leads to the monotonic increase of the gain in time, or gives the optimum amplitude. Transition to the pulsating gas flow in a circulating fluidized bed reactor leads to considerable gain in time of particle treatment only in the case of strong dependence of the reaction rate constant on the velocity of flow around the particle. In this case the optimum frequency and amplitude of oscillation exist that gives the maximum gain in time.

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A new correlation for predicting solids concentration in the fully developed zone of circulating fluidized bed risers

Cited by 36 publications

References 20 publications

Cold Model Study of a 1.5 MW_th Circulating Turbulent Fluidized Bed Fuel Reactor in Chemical Looping Combustion

Cold Model Study of a 1.5 MW_th Circulating Turbulent Fluidized Bed Fuel Reactor in Chemical Looping Combustion

Simulation of mass balance behavior in a large-scale circulating fluidized bed reactor

Influence of gas flow oscillation on the efficiency of particulate solids treatment in a circulating fluidized bed

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A new correlation for predicting solids concentration in the fully developed zone of circulating fluidized bed risers

Cited by 36 publications

References 20 publications

Cold Model Study of a 1.5 MWth Circulating Turbulent Fluidized Bed Fuel Reactor in Chemical Looping Combustion

Cold Model Study of a 1.5 MWth Circulating Turbulent Fluidized Bed Fuel Reactor in Chemical Looping Combustion

Simulation of mass balance behavior in a large-scale circulating fluidized bed reactor

Influence of gas flow oscillation on the efficiency of particulate solids treatment in a circulating fluidized bed

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Product

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Cold Model Study of a 1.5 MW_th Circulating Turbulent Fluidized Bed Fuel Reactor in Chemical Looping Combustion

Cold Model Study of a 1.5 MW_th Circulating Turbulent Fluidized Bed Fuel Reactor in Chemical Looping Combustion