基于计算颗粒流体力学(CPFD)方法对甲烷无氧芳构化催化反应/催化剂再生系统中的流化床反应器进行了数值模拟,并将模拟结果与实验结果进行比较,验证了CPFD模拟的可行性。通过模拟得到了反应器内整体气固流动状态、气相各组分浓度分布及催化剂积碳含量分布等,考察了不同操作条件如甲烷进料流量及反应器内催化剂存留量对气固两相流动及甲烷无氧芳构化反应性能的影响。结果表明,甲烷进料流量增加会降低甲烷转化率,提高芳烃选择性;反应器内催化剂存留量增加会加剧床内气固两相的返混程度,提高甲烷转化率,降低芳烃选择性。
Non-oxidative methane dehydroaromatization (MDA) is a promising technology for converting methane into high value-added products such as benzene, naphthalene, and hydrogen. The fluidized bed has good mass and heat transfer characteristics and is easy to realize the continuous regeneration of the catalyst, so it is an ideal MDA reactor. The basic research on fluidization in MDA fluidized bed reactors is one of the important links to realize the industrialization of MDA technology. In this work, the coupling model of reactions and hydrodynamics was established, and the fluidized bed reactor of the methane dehydroaromatization catalytic reaction/catalyst regeneration system, which has been constructed by our laboratory, was numerically simulated based on the computational particle fluid dynamics (CPFD) method. Then, the simulated values were compared with the corresponding experimental results, which validated the feasibility of CPFD simulation. Through simulation, the overall gas-solid flow state, the concentration distribution of each component in the gas phase and the catalyst carbon deposition content distribution were predicted. Finally, the effects of different operating conditions such as methane feed flow and catalyst retention in the reactor on the gas-solid two-phase flow and methane dehydroaromatization reaction performance were investigated. The results showed that the increase of methane feed flow rate reduced the methane conversion and improve the selectivity of aromatic products. Increasing the catalyst retention in the reactor can improve the methane conversion, meanwhile, it also made the axial and radial non-uniformity of the gas-solid two-phase distribution in the gas-solid reactor more significant, resulting in increased gas backmixing and lower the aromatic selectivity. This work would deepen the understanding of the gas-solid flow patterns inside the MDA fluidized bed reactor and provide some valuable data support for the industrial reactor scale-up of this technology.