Effect of process parameters on circulating fluidized bed coal gasification using 3D full‐loop CFD simulation

Abstract

This article presents a 3D full‐loop computational fluid dynamics (CFD) simulation of a circulating fluidized bed gasifier (CFBG). The simulation results are validated against the experimental data and found to be in good agreement. Thereupon, the effect of the process parameters, ie, temperature, pressure, air/coal (A/C) ratio, and steam/coal (S/C) ratio, on the performance of the gasifier is analyzed. The effect of temperature on the hydrodynamics was found to be small. The CO and H2 increase, whereas the CO2 and H2O decrease with an increase in temperature. While the effect of pressure on the outlet species mole fraction is negligible, the gas and solid axial velocity decrease with an increase in pressure. With an increasing A/C ratio or decreasing S/C ratio, the combustion products (CO2 and H2O) increase, whereas the gasification products (CO and H2) decrease due to the increase in the O2 concentration. In addition, temperature increases with an increase in the A/C ratio or a decrease in the S/C ratio. The feed velocity increases with an increasing A/C or S/C ratio, and, accordingly, the pressure increases and bed height decreases. The CH4 decreases in all of the cases as it is being consumed in gasification as well as combustion reactions.

Hydrodynamic Full-Loop Simulation of an Industrial Fluid Catalytic Cracking Fluidized Bed System with Mechanical Valves

“…Muhammad et al realized a 3D simulation of a full-loop CFB system using the dense discrete phase model (DDPM) and explored the effects of drag model, parcel size, and collisional restitution coefficient on hydrodynamic behaviors. Sharma et al conducted a 3D simulation of a single-loop CFB furnace with the TFM to investigate the effects of process parameters on hydrodynamics, temperature, and syngas content. Yang et al used the MP-PIC method for simulations of a pilot-scale CFB system with a J-valve and explored the relationship between solid residence time, pressure distribution, and superficial gas velocity.…”

Effect of coal particle size on gasification performance of two‐stage entrained‐flow coal gasifier

“…The characteristics and reactivity of coal gasification are important to gasifiers' performance evaluation. Much work has been done on coal pyrolysis and gasification in fluidized beds [6][7][8][9] and entrained-flow gasifiers. [1][2][3][4][10][11][12][13] The effects of coal type and operating conditions (temperature, pressure, and gasify agencies) on gasification reactivity have been extensively investigated, and the particle size has also been found to significantly influence the ignition and thermal history of coal particle, and consequently the flame distribution and gasification characteristics.…”

Numerical analysis of the operating characteristics of a large‐scale CFB coal‐gasification reactor with the QC‐EMMS drag model

“…As can be seen in Table 1, the CFB coal gasifier studied in this work has much larger sizes and higher coal capacity compared with the gasifiers reported in previous work. [ 9–15 ] Therefore, further investigations of this gasifier will enhance understanding of the gasification characteristics of the large‐scale CFB coal gasifier, and provide more theoretical foundations for industrial applications.…”