Energy and Exergy Balance in the Process of Pulverized Coal Combustion in a Tubular Combustor

2005 ◽  
Vol 127 (12) ◽  
pp. 1322-1333 ◽  
Author(s):  
S. K. Som ◽  
S. S. Mondal ◽  
S. K. Dash
Keyword(s):  
Coal Combustion ◽  
Particle Diameter ◽  
Pulverized Coal ◽  
Operating Conditions ◽  
Second Law ◽  
Pulverized Coal Combustion ◽  
Two Phase ◽  
Thermodynamic Irreversibility ◽  
Coal Particles ◽  
Exergy Balance

A theoretical model of exergy balance, based on availability transfer and flow availability, in the process of pulverized coal combustion in a tubular air-coal combustor has been developed to evaluate the total thermodynamic irreversibility and second law efficiency of the process at various operating conditions. The velocity, temperature, and concentration fields required for the evaluation of flow availability have been computed numerically from a two-phase separated flow model on a Eulerian-Lagrangian frame in the process of combustion of pulverized coal particles in air. The total thermodynamic irreversibility in the process has been determined from the difference in the flow availability at the inlet and outlet of the combustor. A comparative picture of the variations of combustion efficiency and second law efficiency at different operating conditions, such as inlet pressure and temperature of air, total air flow rate and inlet air swirl, initial mean particle diameter, and length of the combustor, has been provided to shed light on the trade-off between the effectiveness of combustion and the lost work in the process of pulverized coal combustion in a tubular combustor.

Energy and Exergy Balance in the Process of Spray Combustion in a Gas Turbine Combustor

2002 ◽  
Vol 124 (5) ◽  
pp. 828-836 ◽  
Author(s):  
S. K. Som ◽  
N. Y. Sharma
Keyword(s):  
Gas Turbine ◽  
Gas Phase ◽  
Transport Processes ◽  
Operating Conditions ◽  
Spray Combustion ◽  
Second Law ◽  
Gas Turbine Combustor ◽  
Thermodynamic Irreversibility ◽  
Entropy Transport ◽  
Exergy Balance

A theoretical model of exergy balance based on availability transfer and flow availability in the process of spray combustion in a gas turbine combustor has been developed to evaluate the total thermodynamic irreversibility and second law efficiency of the process at various operating conditions, for fuels with different volatilities. The velocity, temperature and concentration fields in the combustor, required for the evaluation of the flow availabilities and process irreversibilities, have been computed numerically from a two phase separated flow model of spray combustion. The total thermodynamic irreversibility in the process of spray combustion has been determined from the difference in the flow availability at inlet and outlet of the combustor. The irreversibility caused by the gas phase processes in the combustor has been obtained from the entropy transport equation, while that due to the inter-phase transport processes has been obtained as a difference of gas phase irreversibilities from the total irreversibility. A comparative picture of the variations of combustion efficiency and second law efficiency at different operating conditions for fuels with different volatilities has been made to throw light on the trade off between the effectiveness of combustion and the lost work in the process of spray combustion in a gas turbine combustor.

Development and Validation of a Coal Combustion Model for Pulverised Coal Combustion

2010 ◽  
Author(s):  
M. J. Chernetsky ◽  
A. A. Dekterev
Keyword(s):  
Coal Combustion ◽  
Pulverized Coal ◽  
Laboratory Scale ◽  
Combustion Model ◽  
Pulverized Coal Combustion ◽  
Nox Formation ◽  
Coal Particles ◽  
Model Predictions ◽  
Char Burnout ◽  
Development And Validation

To fully understand the processes of heat-and-mass transfer on the laboratory-scale and full-scale coal boilers, computer models are needed to develop, which can predict flow fields, heat transfer and the combustion of the coal particles with reasonable accuracy. In the work reported here, a comprehensive model for pulverized coal combustion has been presented. Attention has been given to the char burnout submodel, NOx formation sub-model and accurate calculation of the temperature of the particles. The model predictions have been compared with the experimental measurements of the laboratory-scale pulverized-coal combustion burner.

Large-Eddy Simulation on a Pulverized Coal Combustion Furnace With a Complex Burner

2011 ◽  
Author(s):  
Hiroaki Watanabe ◽  
Kenji Tanno ◽  
Ryoichi Kurose ◽  
Satoru Komori
Keyword(s):  
Large Eddy Simulation ◽  
Coal Combustion ◽  
Pulverized Coal ◽  
Combustion Model ◽  
Pulverized Coal Combustion ◽  
Direct Closure ◽  
Recirculation Flow ◽  
Eddy Simulation ◽  
Coal Particles ◽  
Large Eddy

Large-eddy simulation (LES) is applied to a pulverized coal combustion field in a combustion test furnace with a practical advanced low NOx burner called CI-α burner, and its validity is investigated by comparing with the experiment. The motion of coal particles is calculated by the Lagrangian method with a parcel model. In the coal combustion modeling, three chemical processes are considered, namely devolatilization, char combustion and gaseous combustion. The direct closure SSFRRM (scale similarity filtered reaction rate model) is used as a turbulent combustion model. The results show that a swirling recirculation flow is formed in the central region close to the burner and its size and strength dynamically change with time. The predicted distributions of gaseous temperature and oxygen are in general agreement with the experiment.

ASSESSMENT OF TWO-PHASE FLOW MODELS FOR THE SIMULATION OF PULVERIZED COAL COMBUSTION

Clean Air ◽  
2005 ◽  
Vol 6 (3) ◽  
pp. 267-287 ◽  
Author(s):  
Bernd Epple ◽  
Woody Fiveland ◽  
Bernd Krohmer ◽  
Galen Richards ◽  
Ali C. Benim
Keyword(s):  
Coal Combustion ◽  
Two Phase Flow ◽  
Pulverized Coal ◽  
Phase Flow ◽  
Pulverized Coal Combustion ◽  
Two Phase ◽  
Flow Models

Kinetic characteristics of pulverized coal combustion in the two-phase flow

Energy ◽  
2013 ◽  
Vol 55 ◽  
pp. 585-593 ◽  
Author(s):  
Zhengang Li ◽  
Zhancheng Guo ◽  
Xuzhong Gong ◽  
Huiqing Tang
Keyword(s):  
Coal Combustion ◽  
Two Phase Flow ◽  
Pulverized Coal ◽  
Phase Flow ◽  
Pulverized Coal Combustion ◽  
Kinetic Characteristics ◽  
Two Phase
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