Kinetics, Mass Transfer, and Reactor Scaling Up in Production of Direct Dimethyl Ether

A two-phase model was developed for scaling up bubbling fluidized bed reactors for dimethyl ether production. Kinetic model correlations for the reactions were developed from fixed-bed experimental data. In addition, the mass transfer coefficient between the bubble and emulsion phases in a bubbling fluidized bed was estimated from experimental data, and the Sherwood number correlation was reported. Finally, scaling up of a bubbling fluidized bed reactor from laboratory to industrial scale was carried out using three similarity criteria: hydrodynamic, residence time, and performance. The hydrodynamic similarity criterion was shown to be inadequate due to low mass transfer and residence time on a large scale. The criteria of similarities in performance and residence time provide the same dimethyl ether yield in all scales. The two-phase models, combined with correlations developed for kinetic and mass transfer parameters, are useful for analysis of laboratory and industrial-scale reactors, and provide information on scaling up.

Automated summary

A two-phase model was developed to scale up bubbling fluidized bed reactors for dimethyl ether production. Correlations for the kinetic model and mass transfer coefficient were developed from experimental data. Scaling up from laboratory to industrial scale was carried out using three similarity criteria. The hydrodynamic criterion was found to be inadequate, while the criteria for performance and residence time yielded the same dimethyl ether yield in all scales. The two-phase models, combined with correlations for kinetic and mass transfer parameters, are useful for analyzing and scaling up laboratory and industrial-scale reactors.