Effect of turbulence and devolatilization models on coal gasification simulation in an entrained-flow gasifier

Silaen, Armin K.; Wang, Ting

doi:10.1016/j.ijheatmasstransfer.2009.12.047

Cited by 159 publications

(82 citation statements)

References 13 publications

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“…The computational model and submodels (devolatilization, reactions, particle dynamics, gasification) used in the study are the same as initially developed by Silaen and Wang [22] and improved by Lu and Wang [23] [24]. Therefore, the governing and associated equations and detailed modeling intricacies are not repeated here, but they are briefly summarized below.…”

Section: Computational Modelmentioning

confidence: 99%

Simulation of Ash Deposition Behavior in an Entrained Flow Coal Gasifier

Lu¹,

Wang²

2015

IJCCE

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Fly ash deposition is an important phenomenon associated with ash/slag handling and discharge in the entrained-flow coal gasification process. Fouling and slagging inside the gasifier may cause reliability and safety problems because they can impose strong negative effects on the gasifier wall in the way of heat transfer and chemical corrosion. For these reasons, this study focuses on investigating the ash deposition distribution inside of a two-stage entrained-flow gasifier. The computational model is developed in order to simulate the gasification process with a focus on modeling ash formation, fly ash, and ash deposition. The Eulerian-Lagrangian approach is applied to solve the reactive thermal-flow field and particle trajectories with heterogeneous reactions. The governing equations include the Navier-Stokes equations, twelve species transport equations, and ten global chemical reactions consisting of three heterogeneous reactions and seven homogeneous reactions. The coal/ash particles are tracked with the Lagrangian method. The effects of different coal/ash injection schemes and different coal types on ash deposition have been investigated. The results show that the two-stage fuel feeding scheme could distribute the ash throughout a larger gasifier's volume and, hence, could reduce the peak ash deposition rate and make the ash distribution more uniform inside the gasifier. Gasification of a high-ash coal results in a high ash deposition rate, low syngas higher heating value (HHV), and low carbon conversion rate. The result of ash deposition rate in this study can be used as a boundary condition to provide ash particle influx distribution for use in slagging models.

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Section: Computational Modelmentioning

confidence: 99%

Simulation of Ash Deposition Behavior in an Entrained Flow Coal Gasifier

Lu¹,

Wang²

2015

IJCCE

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“…In conclusion, the neglecting of drying and devolatilization is explained by the fact that subgrid models for coal conversion are basically split on three submodels, namely, drying, devolatilization and char conversion [8,17]. In order to validate a sub-model for the partial oxidation of a spherical nonporous char particle moving in an air/steam atmosphere, we use a comprehensive CFD-based model where the oxidation of the residual carbon, or coke, is considered.…”

Section: Cfd-based Modelmentioning

confidence: 99%

“…For instance, a number of works have been published recently on the numerical modeling of pilot-scale gasifiers, e.g. [5][6][7][8][9], and oxy-fuel combustors, e.g. the review [10].…”

Section: Introductionmentioning

confidence: 99%

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From Detailed Description of Chemical Reacting Carbon Particles to Subgrid Models for CFD

Schulze

Kestel

Nikrityuk

et al. 2013

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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. Trois réactions hétérogènes sont utilisées, ainsi que deux réactions semi-globales homogènes, à savoir l'oxydation du monoxyde de carbone et la réaction du gaz à l'eau. Les particularités distinctives du modèle de sous-maille se trouvent dans la prise en compte de l'influence des réactions homogènes sur les caractéristiques intégrales telles que les taux de combustion du carbone et la température de la particule. Le sous-modèle a été validé en comparant ses résultats avec un modèle complet basé sur la CFD résolvant les questions de flux volumique et de couche limite autour de la particule. Dans ce modèle, les équations de Navier-Stokes couplées aux équations de conservation de l'énergie et des espèces ont été utilisées pour résoudre le problème au moyen de l'approche en état pseudo-stationnaire. À la surface de la particule, l'équilibre de la masse, de l'énergie et de la concentration des espèces a été appliqué, y compris l'effet de l'écou-lement de Stefan et l'effet de la perte de chaleur due aux rayonnements à la surface de la particule. Une bonne adéquation a été atteinte entre le sous-modèle et le modèle basé sur la CFD. En outre, le modèle basé sur la CFD a été comparé aux données expérimentales publiées dans la littérature (Makino et al. (2003) Combust. Flame 132, 743-753). Une bonne concordance a été atteinte entre les données prédites numériquement et celles obtenues expérimentalement pour les conditions d'entrée correspondant au régime contrôlé par la cinétique. La divergence maximale (10 %) entre les expériences et les résultats numériques a été observée dans le régime contrôlé par la diffusion. Enfin, nous discutons de l'influence du nombre de Reynolds, de la fraction massique d'O 2 ambiant et de la température ambiante sur le comportement de la particule de charbon. Abstract -From Detailed Description of Chemical Reacting Carbon Particles to Subgrid Models for CFD -This work is devoted to the development and validation of a sub-model for the partial oxidation of a spherical char particle moving in an air

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“…A discrete-phase-model (DPM) is employed to track the trajectories of fuel particles through the continuous fluid phase. In this model, the trajectories of coal particles are tracked when they move through the continuous phase of the fluid [20]. The interaction between the discrete phase and the continuous phase is also taken into account by treating the heat and mass losses of the particles as the source terms in the governing equations.…”

Section: Assumptions and Governing Equationsmentioning

confidence: 99%

Optimization of Co-Gasification Process in an Entrained-Flow Gasifier Using the Taguchi Method

Chen

Hung

2013

JTST

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Gasification has played an important role in the development of clean coal technology. To seek appropriate operations for synthesis gas (syngas) formation, the present study developed an optimization analysis procedure of the gasification process in an entrained-flow gasifier through the application of the Taguchi method in conjunction with a simulation method. The effects of the wall temperature, O/F ratio, feed type and pressure on the performance of cold gas efficiency (CGE) were investigated. An orthogonal array was used to arrange the CFD experimental plan for the above factors. Analysis of the signal-to-noise ratio (S/N ratio) was used to evaluate the calculation results. Results suggest that the optimum conditions are a wall temperature of 1500 K, an O/F ratio of 0.6, coal feed type and a gasifier pressure of 3 MPa. The influence strength order of each control condition is feed type＞O/F ratio＞wall temperature＞pressure. The value of the S/N ratio for the optimum case is 13.40, which is the highest value compared to other cases. Findings show that the Taguchi method is able to investigate the gasification process well and can therefore be applied in future studies conducted in various fields.

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Effect of turbulence and devolatilization models on coal gasification simulation in an entrained-flow gasifier

Cited by 159 publications

References 13 publications

Simulation of Ash Deposition Behavior in an Entrained Flow Coal Gasifier

Simulation of Ash Deposition Behavior in an Entrained Flow Coal Gasifier

From Detailed Description of Chemical Reacting Carbon Particles to Subgrid Models for CFD

Optimization of Co-Gasification Process in an Entrained-Flow Gasifier Using the Taguchi Method

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