10 MWth化学链燃烧反应装置的CPFD模拟

doi:10.11949/0438-1157.20240224

摘要/Abstract

摘要：

对自主设计的10 MW_th化学链燃烧装置进行了全流程全尺度的计算颗粒流体力学（CPFD）模拟，得到了系统内详细的气固两相流流体动力学信息。首先基于经典实验验证了各曳力模型的可靠性，利用优选的EMMS-Yang曳力模型对系统进行了全流程模拟，分析了系统内的压力平衡，之后分析了系统内的固体循环流量，反应器内固含率分布、压力分布等关键参数，补充了实际运行过程中难以测量的细节信息，同时可以指导操作条件优化及反应器调控策略。模拟结果显示，系统实现了良好的压力平衡，空气反应器出口固体循环流量达到103.80 kg/s，燃料反应器出口固体循环流量达到40.10 kg/s，底部返料阀返料顺畅，使得系统快速达到稳定运行状态。

关键词: 化学链燃烧, CPFD模拟, 曳力模型, 压力平衡

Abstract:

This paper presents a comprehensive computational particle fluid dynamics (CPFD) simulation of a self-designed 10 MW_th chemical looping combustion (CLC) reactor, providing detailed gas-solid two-phase flow hydrodynamic information within the system. First, the reliability of various drag models was validated based on classical experiments. Subsequently, utilizing the preferred EMMS-Yang drag model, the system was simulated comprehensively to analyze pressure balance within the system. Furthermore, the key parameters such as solid circulation rate, solid concentration distribution within the reactor, and pressure distribution were analyzed. The detailed results which are difficult to measure in operation can guide the development of operational conditions optimization and reactor control strategies. The simulation results show that the reactor system realizes good pressure balance, the solid circulation rate at the outlet of the air reactor reaches 103.80 kg/s, the solid circulation rate at the outlet of the fuel reactor reaches 40.10 kg/s, and the lower loop seal returns the material smoothly, which makes the system reach the stable operation state quickly.

Key words: chemical looping combustion, CPFD simulation, drag models, pressure balance

中图分类号:

TQ 028.8

童永祺, 程杰, 林海, 陈曦, 赵海波. 10 MW_th化学链燃烧反应装置的CPFD模拟[J]. 化工学报, 2024, 75(8): 2949-2959.

Yongqi TONG, Jie CHENG, Hai LIN, Xi CHEN, Haibo ZHAO. CPFD simulation of a 10 MW_th chemical looping combustion reactor[J]. CIESC Journal, 2024, 75(8): 2949-2959.

图/表 14

图1 10 MWth化学链燃烧装置计算模型、初始物料分布及进出口边界

Fig.1 10 MWth chemical looping combustion unit computational modeling, initial material distribution and boundary conditions

表1 模拟中采用的参数

Table 1 Parameters used in the simulation

参数	数值
AR高度/m	17
FR高度/m	17
AR截面积/m²	1.8
FR截面积/m²	0.93
总填料量/kg	25000
初始颗粒堆积浓度	0.58
网格数/个	558568
时间步长/s	0.0001
计算总时长/s	60
空气反应器温度/K	1223
燃料反应器温度/K	1183

表2 模拟中的进出口参数

Table2 Import and export parameters in the simulation

名称	类型	压力/Pa	表观气速/(m/s)
AR_inlet	速度入口	—	8.000
AR_outlet	压力出口	101325	—
AR_LS_inlet1	速度入口	—	0.024
AR_LS_inlet2	速度入口	—	0.121
AR_LLS_inlet	速度入口	—	0.150
FR_inlet	速度入口	—	4.000
FR_outlet	压力出口	101325	—
FR_LS_inlet1	速度入口	—	0.024
FR_LS_inlet2	速度入口	—	0.121
FR_LLS_inlet	速度入口	—	0.100
Thermal_wall	热流壁面	—	—

图2 网格无关性验证

Fig.2 Mesh-independent verification

表3 氧载体颗粒反应动力学参数

Table 3 Kinetic parameters for the reaction of oxygen carrier particles

参数	单位	CH₄	O₂
ρ_m	mol/m³	32811	22472
r_g	m	2.6×10^-7	2.6×10^-7
b	—	12	4
k₀	mol^1-ⁿ ·m³ⁿ^-2/s	8.0×10^-4	3.1×10^-4
E	kJ/mol	49	14
n	—	1.3	1.0
C_g	%（体积分数）	3	11

表4 经典实验工况颗粒参数

Table 4 Particle parameters for classical experimental conditions

粒径/μm	平均粒径/μm	密度/(kg/m³)	最小流化速度/(m/s)	终端速度/(m/s)	颗粒分类
70~240	139	2400	0.091	1.2	B

图3 不同曳力模型颗粒在反应器内的分布情况[(a)~(d)分别为EMMS-Yang、WenYu-Ergun、Turton-Levenspiel、Nonspherical-Ganser曳力模型t=60 s时刻的颗粒瞬时分布；(e)~(h)为四种曳力模型稳态时颗粒的平均固含率分布]

Fig.3 Distribution of particles in the reactor for different drag models[(a)—(d) are the instantaneous distributions of particles at the moment of t=60 s for EMMS-Yang, WenYu-Ergun, Turton-Levenspiel, and Nonspherical-Ganser tracer models, respectively; (e)—(h) are the distributions of particles' average solids content in steady state for the four drag models]

图4 不同曳力模型下床层空隙率沿高度分布情况

Fig.4 Distribution of bed void fraction along height for different drag models

图5 计算模型内流量截面的设置

Fig.5 Flux plane settings within the simulation model

图6 各个流量截面处的固体循环速率与平均值

Fig.6 Instantaneous solids circulating rates and mean values at each flux plane

图7 运行稳定后系统压力分布情况（时均值）

Fig.7 System pressure distribution after operational stabilization (time averaged)

图8 氧载体外循环系统压力分布及氧载体FR内循环系统压力分布

Fig.8 Oxygen carrier external circulation system pressure distribution and oxygen carrier FR internal circulation system pressure distribution

图9 不同时刻底部返料阀内颗粒分布

Fig.9 Particle distribution in the bottom return valve at different moments

图10 底部返料阀内的时均云图

Fig.10 Time-averaged distribution in the bottom return valve

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