固定床反应器中甲醇制芳烃工业催化剂结构影响的研究

doi:10.11949/0438-1157.20250378

摘要/Abstract

摘要：

甲醇制芳烃是一种可行的替代石油路线的芳烃生产技术，其关键在于开发高性能甲醇制芳烃工业催化剂。考虑到反应器尺度传递过程会影响工业催化剂的整体性能，建立了从工业催化剂到固定床反应器的双尺度颗粒分辨计算流体力学模型，并借助该模型探究了工业催化剂结构对甲醇制芳烃性能的影响规律。结果显示，拉西环催化剂颗粒对应的床层空隙率大，催化剂内扩散限制小，相比于其他催化剂外形具有最低的床层压降和较高的反应器出口芳烃收率。减小催化剂颗粒粒径能有效提升反应器出口芳烃收率，但是也会显著增加反应器压降。催化剂孔径为200 nm以及空隙率为0.5时能有效平衡催化剂内扩散以及催化材料含量和分布，显示出最高的反应器出口芳烃收率。研究结果将为甲醇制芳烃工业催化剂设计优化提供一种强大的模型工具以及一些重要的理论依据。

关键词: 甲醇制芳烃, 多孔介质, 填充床, 计算流体力学, 传递

Abstract:

Methanol to aromatics is a feasible process to produce aromatics without using petroleum as feedstock, and the key to this process is developing high-performance industrial catalysts. This work builds a two-scale particle-resolved computational fluid dynamics model that describes transfer and reaction from industrial catalyst particle to packed bed reactor, considering the transfer process at the reactor scale would affect the overall performance of industrial catalysts. With this two-scale model, the effects of industrial catalyst structure on methanol to aromatics are investigated. The results show that the Raschig ring catalyst particles have a large bed void ratio and small diffusion restriction in the catalyst. Compared with other catalyst shapes, they have the lowest bed pressure drop and higher reactor outlet aromatics yield. Reducing catalyst particle size is effective in increasing the aromatic yield at reactor outlet, but significantly rises the pressure drop. The catalyst with 200 nm pore size and 0.5 porosity can effectively balance internal diffusion as well as catalyst amount and active site distribution, and thus its corresponding catalyst bed shows the highest aromatic yield at reactor outlet. These results in this work provide a powerful model and some important theoretical guidance for the development of industrial catalysts for methanol to aromatics.

Key words: methanol to aromatics, porous media, packed bed, computational fluid dynamics, transport

中图分类号:

TQ 021.4

解勤勤, 翁俊旗, 林振利, 叶光华, 周兴贵. 固定床反应器中甲醇制芳烃工业催化剂结构影响的研究[J]. 化工学报, 2025, 76(9): 4487-4498.

Qinqin XIE, Junqi WENG, Zhenli LIN, Guanghua YE, Xinggui ZHOU. Effects of industrial catalyst structure on methanol to aromatics in a packed bed reactor[J]. CIESC Journal, 2025, 76(9): 4487-4498.

图/表 12

图1 甲醇制芳烃的反应网络[25]

Fig.1 Reaction network of methanol to aromatics[25]

表1 集总动力学模型参数［25］

Table 1 Parameters for the lumped kinetics model［25］

反应编号 i	活化能 $E a i$ /(J/mol)	指前因子A_i /h^-1
1	2.08×10⁴	1.61×10³
2	6.99×10⁴	3.64×10⁶
3	7.87×10³	1.46×10²
4	2.17×10⁴	1.13×10³
5	6.05×10³	1.06×10²
6	5.98×10⁴	1.45×10⁶

表1 集总动力学模型参数［25］

Table 1 Parameters for the lumped kinetics model［25］

反应编号 i	活化能 $E a i$ /(J/mol)	指前因子A_i /h^-1
1	2.08×10⁴	1.61×10³
2	6.99×10⁴	3.64×10⁶
3	7.87×10³	1.46×10²
4	2.17×10⁴	1.13×10³
5	6.05×10³	1.06×10²
6	5.98×10⁴	1.45×10⁶

图2 网格结构示意(a)和网格敏感性分析(b)

Fig.2 Structures of the meshes (a), and mesh sensitivity analysis (b)

表2 本文模拟所用参数

Table 2 Simulation parameters in this work

参数	数值
入口速度u_in/(m/s)	0.2
压力P_in/MPa	0.1
入口温度T_in/K	630
壁温T_wall/K	630
催化剂孔隙率ε_cat	0.5
催化剂孔径d_p/nm	20
催化剂直径d_s/mm	8
催化剂密度ρ_s/(kg/m³)	2230
反应管直径d_t/mm	40
床层高度L/mm	110

图3 催化剂床层压降模拟值与实验值对比[39]

Fig.3 Comparison of the pressure drops in a catalyst bed calculated by the model in this work and obtained from experiments[39]

图4 不同反应管直径下的床层空隙率和压降(a)，反应器出口甲醇和二甲醚（集总a）转化率和芳烃收率(b)，轴向(c)和径向床层空隙率(d)

Fig.4 Bed voidages and pressure drops (a), conversions of methanol and dimethyl ether (lumped component a) and yields of aromatics at reactor outlet (b), axial (c) and radial bed voidages under different tube diameters (d)

图5 不同反应管直径下的床层流速(a)、温度(b)和芳烃浓度分布(c)

Fig.5 Distributions of fluid velocity magnitude(a), temperature (b) and concentration of aromatics (c) under different tube diameters

图6 不同形状催化剂颗粒床层的空隙率和压降(a)、速度分布(b)、集总a的转化率和芳烃的收率(c)以及芳烃浓度分布(d)

Fig.6 Voidages and pressure drops (a), velocity magnitude distributions (b), conversions of lumped component a and yields of aromatics (c), and concentration distribution of aromatics (d) for the beds packed with catalyst particles of different shapes

表3 不同形状催化剂颗粒的结构参数

Table 3 Structural parameters of catalyst particles of different shapes

尺寸

d = 8.00 mm

d = 6.53 mm，

l = 8.00 mm

d_out = 7.54 mm，

d_in = 3.77 mm，

l = 8.00 mm

d = 6.98 mm，

l = 8.00 mm

d_out = 7.54 mm，

d_in = 1.89 mm，

l = 8.00 mm

图7 不同尺寸催化剂颗粒床层的空隙率和压降(a)、集总a的转化率和芳烃的收率(b)、轴向(c)和径向床层空隙率(d)、速度分布(e)，以及芳烃浓度分布(f)

Fig.7 Voidages and pressure drops (a), conversions of lumped component a and yields of aromatics (b), axial (c) and radial bed voidages (d), velocity magnitude distributions (e), and concentration distribution of aromatics (f) for the beds packed with catalyst particles of different sizes

图8 不同催化剂孔径下反应器出口的集总a转化率和芳烃收率(a)以及芳烃浓度分布(b)

Fig.8 Conversions of lumped component a and yields of aromatics at reactor outlet (a), and concentration distributions of aromatics (b) for the beds packed with catalyst particles of different pore diameters

图9 不同催化剂孔隙率下反应器出口的集总a转化率和芳烃收率(a)以及芳烃浓度分布(b)

Fig.9 Conversions of lumped component a and yields of aromatics at reactor outlet (a), and concentration distributions of aromatics (b) for the beds packed with catalyst particles of different porosities

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