Circulating fluidized bed combustion reactor: Computational Particle Fluid Dynamic model validation and gas feed position optimization

Thapa, Rajan Kumar; Frohner, Andreas; Tondl, Gregor; Pfeifer, Christoph; Halvorsen, Britt

doi:10.1016/j.compchemeng.2016.05.008

Cited by 41 publications

(25 citation statements)

References 25 publications

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“…The particle circulation rate had been experimentally calculated by interrupting the loopseal aeration and measuring the time to build up a certain amount of particles (the bed height) in the standpipe (Thapa et al 2016). This might substantially influence the particle hydrodynamics in the riser, as the particles are not fed to the riser from the loopseal.…”

Section: Resultsmentioning

confidence: 99%

“…Model validation is based on experimental studies performed in a full loop CFB unit, which is illustrated in Figure 3. Detailed experimental procedure is given in the work of Thapa et al (2016). Sand with particle density of 2650 kg/m 3 and mean diameter of 150 mm was used as the particle phase and air was used as the fluidizing medium.…”

Section: Experimental and Cfd Model Set Upmentioning

confidence: 99%

“…CPFD simulations have been used to analyze the nonreactive fluidized bed systems (Snider 2007;Qiu, Ye, and Wang 2015) and reactive systems like combustion and gasification of biomass and coal. (Snider and Banerjee 2010;Abbasi, Ege, and de Lasa 2011;Snider, Clark, and O'Rourke 2011;Xie et al 2012;Loha, Chattopadhyay, and Chatterjee 2014;Thapa et al 2016).…”

Section: Introductionmentioning

confidence: 99%

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Circulating fluidized bed reactors – part 01: analyzing the effect of particle modelling parameters in computational particle fluid dynamic (CPFD) simulation with experimental validation

Bandara

Thapa

Nielsen

et al. 2019

Particulate Science and Technology

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A CPFD hydrodynamic model was developed for a circulating fluidized bed system and the simulation results were validated against experimental data based on particle circulation rate. Sensitivity of the computational mesh was primarily tested and extended grid refinement was needed at the loopseal to match the particle circulation rate with experimental data. The particle circulation rate was independent of the range of number of computational particles used in this study. A 10% reduction of the particle circulation rate was observed as the particle-wall interaction parameter was changed from 0.85 to 0.55 and 17% increment when the close-packed volume fraction was changed from 0.56 to 0.62. The pressure constant in the particle stress model showed the greatest impact for the circulation rate with 57% increment as the constant was changed from 2.5 to 5. The highest absolute variation in the pressure was observed at the loop seal and pressure values were under predicted in all sections. HIGHLIGHTS CPFD simulations are efficient in analyzing fluidized bed systems. Manipulating of particle circulation rate is important in circulating fluidized bed. Pressure constant in particle stress model is the most influential factor. Uncertainties should be minimized prior to optimization of model parameters.

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Section: Resultsmentioning

confidence: 99%

Section: Experimental and Cfd Model Set Upmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Circulating fluidized bed reactors – part 01: analyzing the effect of particle modelling parameters in computational particle fluid dynamic (CPFD) simulation with experimental validation

Bandara

Thapa

Nielsen

et al. 2019

Particulate Science and Technology

View full text Add to dashboard Cite

show abstract

“…the wen and yu drag model is used in the simulations [8]. the sphericity was set to 0.84 and the close pack volume fraction was set to 0.54. detailed information about transport equations, solvers and model development in barracuda is presented in [9], [10], [11]. the validation of the model is performed with particles with a mean diameter of 293 µm.…”

Section: Cpfd Modelling and Simulationmentioning

confidence: 99%

Experimental and computational studies on biomass gasification in fluidized beds

Basmoen¹,

Deeraska²,

Nwosu³

et al. 2019

Int. J. EQ

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ExpErimEntal and computational studiEs on biomass gasification in fluidizEd bEds tommy basmoEn, chidapha dEEraska, chimunchE nwosu, Ebrahim QarEdaghi, rajan jaiswal, nora c.i. furuvik, & britt m.E. moldEstad university of south-Eastern norway, norway.abstract the world's energy consumption is increasing, and research regarding utilization of renewable energy sources is crucial. biomass for direct heating has been used for thousands of years, while in the last decades alternative ways to exploit biomass have emerged. in order to increase the efficiency and to produce more applicable products, gasification of biomass is becoming a more and more promising technology. for the gasification technology to be competitive, the understanding of the various aspects regarding the gasifier operation, which in turn influences the quality of the product gas, is of utmost importance. the main objective of this work is to investigate the effect of the air to biomass ratio on the produced gas composition in terms of the high-energy components h 2 , ch 4 and co. Experiments were performed with wood chips in a pilot scale gasification reactor. the results show that an air-to-biomass ratio less than one gives the most applicable gas composition. biomass, like wood chips, has a peculiar shape, has a large particle size, is cohesive, and is therefore difficult to fluidize. in a fluidized bed gasifier, a bed material is used to improve the fluidization quality. Experiments were carried out in a cold bed model to study the fluidization properties of the bed material. minimum fluidization velocities were predicted based on pressure drop in the bed.

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“…Simulation results matched quite well the experimental data with regards to the syngas composition. Thapa et al (2016) carried out an optimization study of a circulating fluidized bed using the CPFD method and the results were validated against experimental results. Particularly, they found a good agreement between pressure drop and solid circulation rate with respect experimental data.…”

Section: Introductionmentioning

confidence: 99%

Modeling and Simulation of an Oxygen-Blown Bubbling Fluidized Bed Gasifier using the Computational Particle-Fluid Dynamics (CPFD) Approach

Nardo

Calchetti

Stendardo

2018

JAFM

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Fluidized beds are conventional components of many industrial processes, such as coal gasification for energy generation and syngas production. Numerical simulations help to properly design and understand the complex multiphase flows occurring in these reactors. Two modeling approaches are usually adopted to simulate multiphase flows: the two fluids Eulerian-Eulerian model and the continuous/discrete Eulerian-Lagrangian model. Since fluidized beds account for an extremely large number of particles, tracking each of them could not assure to get results within a reasonable computational time. The Computational Particle-Fluid Dynamics (CPFD) approach, which belongs to the Eulerian-Lagrangian models class, groups together particles with similar key parameters (e.g. composition, size) into computational units (parcels). Parcel collisions are modeled by an isotropic solid stress function, depending on solid volume fraction. In this paper, the bubbling fluidized bed (BFB) upstream gasifier of the EU research infrastructure ZECOMIX (Zero Emissions of Carbon with Mixed technologies) has been simulated using a CPFD approach via Barracuda ® software. The effect of different fluidizing agent injection strategies on bed bubbling and mixing, for non-reacting cases, has been studied. The numerical results for a reacting case have been compared to the available experimental data, gathered during the coal gasification campaign. The model has proved to be very useful in the choice of the more efficient injection configuration that assures a more effective contact of the gas with the solid bed and a good bubbling fluidization regime, together with a satisfactory prediction of the outlet gas composition. The numerical approach has turned out to be robust and time-saving and allowed to dramatically reduce the computational cost with respect the classical two fluids Eulerian-Eulerian models.

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Circulating fluidized bed combustion reactor: Computational Particle Fluid Dynamic model validation and gas feed position optimization

Cited by 41 publications

References 25 publications

Circulating fluidized bed reactors – part 01: analyzing the effect of particle modelling parameters in computational particle fluid dynamic (CPFD) simulation with experimental validation

Circulating fluidized bed reactors – part 01: analyzing the effect of particle modelling parameters in computational particle fluid dynamic (CPFD) simulation with experimental validation

Experimental and computational studies on biomass gasification in fluidized beds

Modeling and Simulation of an Oxygen-Blown Bubbling Fluidized Bed Gasifier using the Computational Particle-Fluid Dynamics (CPFD) Approach

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