基于双尺度耦合模拟的甲烷化催化剂多级孔结构探究

Research on the Hierarchical Pore Structure of Methanation Catalyst Based on Dual-Scale Coupling Simulation

以固定床甲烷化反应器中的催化剂颗粒为研究对象,建立了床层-颗粒双尺度耦合模型。针对甲烷化过程反应迅速、催化剂颗粒中内扩散影响显著的特点,探讨了颗粒大孔平均孔径、介孔平均孔径、大孔孔隙率和介孔孔隙率对甲烷化反应结果的影响,提出了多级孔结构催化剂的优化设计,以实现甲烷化过程的强化。模拟结果表明:双尺度耦合模型能较好地在床层尺度下探讨催化剂颗粒的微观孔隙结构对反应结果的影响规律;针对直径为5.4 mm的球形颗粒,在模拟的生产条件下,反应结果对大孔孔隙率和平均介孔直径较为敏感;采用具有大孔和介孔的双模态催化剂颗粒可获得较高的甲烷产率。

Taking the catalyst particles in the methanation fixed bed reactor as the research object,a bed-particle dual-scale coupling model was established.In view of the rapid reaction of the methanation process and the significant influence of internal diffusion in the catalyst particles,the influences of average macropore diameter,average mesopore diameter,macroporous porosity and mesoporous porosity on the methanation reaction results were discussed,and the optimal design of the catalyst with a hierarchical pore structure was proposed to strengthen the methanation process.The simulation results showed that the dual-scale coupling model better explored the influence of the micropore structure of the catalyst particles on the reaction results at the bed scale.For spherical particles with a diameter of 5.4 mm,the performance of the reaction was more sensitive to the macroporous porosity and the average mesopore diameter under the simulated production conditions.The methanation process could obtain a higher methane yield if the dual-modal catalyst with macropore and mesopore was used.