Simulation on the gas-solid flows and combustion in a multi-pass circulating fluidized bed based on computational particle fluid dynamics method

doi:10.3969/j.issn.2097-0706.2024.08.008

Abstract

Abstract:

The furnace temperature of a multi-pass circulating fluidized bed（CFD） is higher than that of a traditional CFD， which advances the miniaturization of CFDs. The gas-olid flows and combustion of a multi-pass CFD were numerically stimulated by computational particle fluid dynamics method. The simulation results fitted well with the results of the pilot-scale experiment. The results indicate that volume fractions of particle phase show core-annulus structure， ranking from high to low in the main combustion chamber， auxiliary combustion chamber， and burnout chamber. The furnace temperature is from 1 000 to 1 200 K. The temperature of the main chamber is higher larger than that of the auxiliary chamber， and the temperature of the auxiliary chamber is higher than that of the burnout chamber and the cyclone separator. Increasing the oxygen content in the dense phase zone of the furnace by enlarging the proportion of primary air to secondary air can intensify the combustion and increase the bed temperature. Pre-classification of fuel at the secondary chamber inlet is beneficial for coke reduction reactions， which is favorable to the reductions of NO concentration and nitrogen oxide emissions.

Key words: multi-pass circulating fluidized bed, gas-solid flow, combustion, computational particle fluid dynamics, numerical simulation

CLC Number:

TK224

SONG Jianjun, FU Kun, CHEN Meiqian. Simulation on the gas-solid flows and combustion in a multi-pass circulating fluidized bed based on computational particle fluid dynamics method[J]. Integrated Intelligent Energy, 2024, 46(8): 59-66.

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参数		数值
一次风量/(kg·s^-1)		3.65
一次风温/K		547
二次风量/(kg·s^-1)		3.65
二次风温/K		547
给煤量/(kg·s^-1)		0.37
给煤风温度/K		300
分离器出口压力/Pa		99 325
颗粒堆积体积分数		0.6
垂直恢复系数e_n		0.3
切向恢复系数e_t		0.99
步长/s		0.001

工业分析（收到基）/%				元素分析（收到基）/%					低位热值/(MJ·kg^-1)
M	V	A	FC	C	H	O	N	S	低位热值/(MJ·kg^-1)
9.0	10.0	32.4	48.6	46.60	3.10	6.10	0.86	1.94	17.69