Search

Themethanol to olefins (MTO) process has been successfully commercializedin China and will potentially become an important route for lightolefins production. In this work, a modeling approach is presentedfor MTO fluidized bed reactor design and operation optimization. Thetwo-fluid model (TFM) where the solid phase shear viscosity and solidphase pressure are derived from kinetic theory of granular flow hasbeen used to model the solid–gas two-phase flows. The interphasedrag force is calculated by either the traditional Gidaspow modelor a recently developed EMMS-bubble model. The simulation study hasbeen performed for a fluidized bed reactor in a 16 kt/a DMTO unit.It has been shown that the Gidaspow model cannot predict a stabledense bed, while the EMMS-bubbling model could simulate the solidfraction distribution in the reactor reasonable well. A reaction modelbased on the simple MTO reaction kinetics has been implemented totest the effectiveness of the model approach. The simulation resultsshow that the methanol is converted rapidly just above the gas inlet.The selectivity of ethylene and propylene however are underpredicted,while the selectivity of CO2and other products are overestimated.It is suggested that a further extension of the EMMS model to a turbulentfluidized bed is important in order to get more quantitative results.Also the MTO reaction kinetics for a commercial DMTO catalyst, inwhich the coke formation kinetics should be included, is highly desired. [ABSTRACT FROM AUTHOR]