A Brief Review on Hydrodynamic Behaviour Analysis of Coal Gasification in a Circulating Fluidized Bed Gasifier

Dwivedi, Krishna Kant; Karmakar, Malay; Pramanick, Achintya Kumar; Chatterjee, P. K.

doi:10.18280/ijht.370316

Cited by 4 publications

(1 citation statement)

References 59 publications

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“…The problem arises of interpreting derivatives in accordance with the specifics of the processes of thermodynamics and heat engineering. It should be borne in mind that the combination of such derivatives forms the organizational and technical tools for the mechanism for regulating the resulting indicator-property of energy efficiency of non-stationary heat transfer processes of the studied heat engineering element and heat power plant in the phase of high-tech organizational and innovative dynamics [20,21]. The evolutionary, spasmodic, bifurcation, lowefficiency, degrading nature of heat transfer processes, of course, must comply with the second and other laws of thermodynamics [22][23][24]:…”

Section: H X a A A A A A A A A A Xmentioning

confidence: 99%

Approximation Methods for Analysis and Formation of Mechanisms for Regulating Heat and Mass Transfer Processes in Heat Equipment Systems

Alabugin¹,

Aliukov²,

Осинцев³

2020

IJHT

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The need to increase the accuracy of decisions and the depth of analysis of complex heat power systems determines the relevance of modeling and regulation of heat and mass transfer processes with the development of theoretical models and the development of a new methodology. Uncertainty of the environment increases the significance of the problems of insufficient efficiency of the available numerical approaches to the modeling of dynamic processes and the regulation of heating elements. Therefore, the aim of the article was to develop the applied aspects of the theory of solving nonlinear problems, provisions of the analytical methodology and the methods for regulating stepwise thermodynamic processes based on adapted tools for approximating generalized and step functions. The following tasks were solved: the structure of mechanisms was determined, including regulators of the energy efficiency of the flare device of the boiler unit with an expanded combustion zone; a model of integration-balancing regulation of heat transfer with four types of unsteady processes determined by indicators of changes in the direction and sign of the entropy of the effects of the regulators is proposed. Quantitative meters of energy efficiency of combustion and heat transfer processes in boiler units have been developed. Mathematical adapted and developed technical and organizational methods for solving problems: approximation of the original functions (generalized Dirac and stepwise) by a sequence of recursive periodic functions; simulation of spasmodic heat transfer processes based on step functions; structuring the mechanism for regulating heat transfer, including four types of regulators; empirical modeling of the assessment and regulation of energy efficiency, taking into account the directivity and severity of the effects of regulators displayed by derivatives of higher orders of approximation of energy efficiency functions. The results were obtained: mathematical ones were adapted and new approximation models for generalized functions were built; quantitative measuring instruments of process dynamics for regulating the technical and organizational mechanisms of heat transfer were obtained.

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Section: H X a A A A A A A A A A Xmentioning

confidence: 99%

Approximation Methods for Analysis and Formation of Mechanisms for Regulating Heat and Mass Transfer Processes in Heat Equipment Systems

Alabugin¹,

Aliukov²,

Осинцев³

2020

IJHT

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Thermal degradation, characterization and kinetic modeling of different particle size coal through TGA

Dwivedi

Prabhansu

Karmakar

et al. 2020

Thermal Science and Engineering Progress

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Three-dimensional CFD simulation and experimental validation of particle segregation in CFB riser

Dwivedi

Pramanick

Karmakar³

et al. 2020

HFF

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Purpose The purpose of this paper is to perform the computational fluid dynamics (CFD) simulation with experimental validation to investigate the particle segregation effect in abrupt and smooth shapes circulating fluidized bed (CFB) risers. Design/methodology/approach The experimental investigations were carried out in lab-scale CFB systems and the CFD simulations were performed by using commercial software BARRACUDA. Special attention was paid to investigate the gas-particle flow behavior at the top of the riser with three different superficial velocities, namely, 4, 6 and 7.7 m/s. Here, a CFD-based noble simulation approach called multi-phase particle in cell (MP-PIC) was used to investigate the effect of traditional drag models (Wen-Yu, Ergun, Wen-Yu-Ergun and Richardson-Davidson-Harrison) on particle flow characteristics in CFB riser. Findings Findings from the experimentations revealed that the increase in gas velocity leads to decrease the mixing index inside the riser. Moreover, the solid holdup found more in abrupt riser than smooth riser at the constant gas velocity. Despite the more experimental investigations, the findings with CFD simulations revealed that the MP-PIC approach, which was combined with different drag models could be more effective for the practical (industrial) design of CFB riser. Well agreement was found between the simulation and experimental outputs. The simulation work was compared with experimental data, which shows the good agreement (<4%). Originality/value The experimental and simulation study performed in this research study constitutes an easy-to-use with different drag coefficient. The proposed MP-PIC model is more effective for large particles fluidized bed, which can be helpful for further research on industrial gas-particle fluidized bed reactors. This study is expected to give throughout the analysis of CFB hydrodynamics with further exploration of overall fluidization.

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A Brief Review on Hydrodynamic Behaviour Analysis of Coal Gasification in a Circulating Fluidized Bed Gasifier

Cited by 4 publications

References 59 publications

Approximation Methods for Analysis and Formation of Mechanisms for Regulating Heat and Mass Transfer Processes in Heat Equipment Systems

Approximation Methods for Analysis and Formation of Mechanisms for Regulating Heat and Mass Transfer Processes in Heat Equipment Systems

Thermal degradation, characterization and kinetic modeling of different particle size coal through TGA

Three-dimensional CFD simulation and experimental validation of particle segregation in CFB riser

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