关键词: 甲烷无氧芳构化, 流化床, 数值模拟, 气固两相流动

Abstract: 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.

Key words: Methane dehydroaromatization, fluidized bed, numerical simulation, gas-solid two-phase flow