Realizing the Commercial Potential of Hierarchical Zeolites

Javier García-Martínez

Universidad de Alicante, Rive Technology, Inc.

The development of intracrystalline mesoporosity within zeolites has been a long-standing goal in catalysis as it greatly contributes to alleviate the diffusion limitations of these widely used microporous materials. During my presentation, I will discuss the main techniques that have been developed during the last years to produce zeolites with controlled mesoarchitectures comparing the different methods, their advantages and limitations. Among the different techniques used to characterize the composition, porosity and structure of these materials, I will present unprecedented insights on the formation of intracrystalline mesoporosity in zeolites obtained by in situ synchrotron X-ray diffraction, Atomic Force Microscopy (AFM), and Liquid Cell Transmission Electron Microscopy (Liq-TEM). By combining experimental results and theoretical calculations, the presence of intracrystalline mesoporosity was recently confirmed. Moreover, through the direct observation of individual zeolite crystals by in situ AFM and Liq-TEM, we have been able to provide the first time resolved visualization of the formation of mesoporosity in zeolites.

The presence of this mesoporosity was further evidenced through ex situ gas adsorption, which also confirmed the preservation of most of the microporosity of the zeolites. All these new insights, obtained by combining a number of time-resolved techniques, are an example of the enormous potential of current in situ characterization methods for the rational design of hierarchical zeolites with superior properties and optimal catalytic performance as it has been proved at lab, pilot plant, and industrial scale.

In a commercial operation in a refinery, a steady increase in LPG olefinicity was observed through replacing the incumbent FCC catalyst by another containing the mesostructured Y zeolite. Commercial data confirmed the observed trend using an equilibrium catalyst from the refinery and analyzed in an ACE unit. A gradual increase in the LPG olefinicity was also observed at the refinery as the concentration of the FCC catalyst containing mesostructured Y zeolite in the circulating inventory steadily increased. In this commercial trial, the most important yield shift was the increase in butylene selectivity. Furthermore, a very valuable increase in gasoline octane was also observed due to a higher concentration of olefins in the lighter gasoline fraction.

The commercialization of hierarchical zeolites through the MIT spin-off Rive Technology as superior refining catalysts is an example of academic entrepreneurship, which is expected to foster the development of new hierarchical zeolites and their use in both existing processes and new opportunities. Finally, I cover other applications of hierarchical zeolites in catalysis, including biomass valorization and fine chemistry, ending with a personal view of the new directions, and opportunities in this field.