Comparative study of MTO kinetics over SAPO-34 catalyst in fixed and fluidized bed reactors

•MTO kinetics in fluidized bed reactor and fixed bed reactor was experimentally studied.•Coke deposition profile leads to different performances in fixed bed and fluidized bed reactor.•Olefin conversion is responsible for the changes of selectivity in fixed bed reactor.•A modeling approach was developed to unify fixed and fluidized bed reactor for MTO process.

In this work, a comparative study on methanol to olefins (MTO) kinetics in fixed and fluidized bed reactors was conducted. Based on the analysis of experimental observations, a modeling approach that can be used to simulate both reactor configurations was proposed. The coke deposition was shown responsible for the difference of product selectivities for these two reactor configurations. In a fluidized bed reactor, the distribution of the coke deposition is spatially uniform, and evolves with time on stream. However, the coke deposition shows a distribution along the bed height in a fixed bed reactor, and olefins conversions were taken into consideration to account for the selectivity changes with time on stream. With the proposed model, we established a linkage between fixed bed reactors and fluidized bed reactors through coke deposition. By use of this model, it is possible to predict the performance of MTO reaction over SAPO-34 catalyst in fluidized bed reactor with experimental data obtained in fixed bed reactor, or verse vice.