The present research work deals with the thermogravimetric analysis (TGA) and kinetic analysis of three typical Indian low rank coals selected from Indian coal mines at various temperature ranges. Experiments were performed at four different heating rate (50, 100, 150, 200 K/min) for three typical Indian low rank coal samples in a nitrogen atmosphere from temperature range 30-950°C. The peak of temperature and mass loss for Indian low rank coal were evaluated. Current study also deals for the utilization and the behaviour of Indian low rank coal during the pyrolysis by using TGA. The activation energy for Indian low rank coal were calculated based on TGA data by using Friedman Method. Corresponding calculated mean value of activation energy for Indian low rank coal is found 49.132 kJ/mol. These experimental results help to explain and predict the behaviour of Indian low rank coal in practical applications.
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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