Reactor-Regenerator System for the Dimethyl Ether-to-Olefins Process over HZSM-5 Catalysts: Conceptual Development and Analysis of the Process Variables

The dimethyl ether (DME)-to-olefins (DTO) process is an interesting alternative to the methanol-to-olefins process because of the easier production of DME, its higher reactivity, and the moderate deactivation exhibited by HZSM-5 catalysts. A design of the reactor-regenerator system has been developed for the prospective implementation of the DTO process using the kinetic models of two catalysts based on zeolites with different acidities (Si/Al ratios of 15 and 140). These kinetic models have been obtained from DTO experimental runs carried out in a packed bed reactor at 325-400 degrees C, up to 6.5 g h mol(c)(-1) and 15 h on stream. The reactor-regenerator model considers the activity distribution function of the catalyst in both fluidized bed units by applying the population balance theory. The influence of process variables (space time, temperature, reactant dilution in water or N-2, catalyst acidity, and mean residence time of the catalyst) on the activity distribution function, conversion, and selectivity to products, mainly olefins, has been studied.