The structure of zeolite Y (Faujasite), with the most r

Fluid catalytic cracking: recent developments on the grand old lady of zeolite catalysis.

Vogt ET, Weckhuysen BM -Chemical Society reviews(2015)

The structure of zeolite Y (Faujasite), with the most relevant ion-exchange sites highlighted. The effect of RE-introduction: XRD: comparing RE-stabilized (blue) with non-stabilized Y-zeolite (red), we observe a shift to lower angles (i.e. larger unit cell size, lower SAR, less dealumination), as well as higher crystallinity in the RE-stabilized material; IR: we observe a shift to lower frequency (lower SAR, less dealumination) for the RE-stabilized form; NMR: we observe larger contributions from Si-species with multiple Al-neighbors (i.e., a lower SAR, less dealumination). All spectra are simulated based on literature data from Roelofsen46 and Scherzer et al.47

fig10:The structure of zeolite Y (Faujasite), with the most relevant ion-exchange sites highlighted. The effect of RE-introduction: XRD: comparing RE-stabilized (blue) with non-stabilized Y-zeolite (red), we observe a shift to lower angles (i.e. larger unit cell size, lower SAR, less dealumination), as well as higher crystallinity in the RE-stabilized material; IR: we observe a shift to lower frequency (lower SAR, less dealumination) for the RE-stabilized form; NMR: we observe larger contributions from Si-species with multiple Al-neighbors (i.e., a lower SAR, less dealumination). All spectra are simulated based on literature data from Roelofsen46 and Scherzer et al.47

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Affiliation:Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands. e.t.c.vogt@uu.nl b.m.weckhuysen@uu.nl.

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Bottom Line:FCC currently produces the majority of the world's gasoline, as well as an important fraction of propylene for the polymer industry.These trends include ways to make it possible to process either very heavy or very light crude oil fractions as well as to co-process biomass-based oxygenates with regular crude oil fractions, and convert these more complex feedstocks in an increasing amount of propylene and diesel-range fuels.After providing some general background of the FCC process, including a short history as well as details on the process, reactor design, chemical reactions involved and catalyst material, we will discuss several trends in FCC catalysis research by focusing on ways to improve the zeolite structure stability, propylene selectivity and the overall catalyst accessibility by (a) the addition of rare earth elements and phosphorus, (b) constructing hierarchical pores systems and (c) the introduction of new zeolite structures.

Abstract

Fluid catalytic cracking (FCC) is one of the major conversion technologies in the oil refinery industry. FCC currently produces the majority of the world's gasoline, as well as an important fraction of propylene for the polymer industry. In this critical review, we give an overview of the latest trends in this field of research. These trends include ways to make it possible to process either very heavy or very light crude oil fractions as well as to co-process biomass-based oxygenates with regular crude oil fractions, and convert these more complex feedstocks in an increasing amount of propylene and diesel-range fuels. After providing some general background of the FCC process, including a short history as well as details on the process, reactor design, chemical reactions involved and catalyst material, we will discuss several trends in FCC catalysis research by focusing on ways to improve the zeolite structure stability, propylene selectivity and the overall catalyst accessibility by (a) the addition of rare earth elements and phosphorus, (b) constructing hierarchical pores systems and (c) the introduction of new zeolite structures. In addition, we present an overview of the state-of-the-art micro-spectroscopy methods for characterizing FCC catalysts at the single particle level. These new characterization tools are able to explain the influence of the harsh FCC processing conditions (e.g. steam) and the presence of various metal poisons (e.g. V, Fe and Ni) in the crude oil feedstocks on the 3-D structure and accessibility of FCC catalyst materials.

Mentions

As mentioned above, the main cracking component in FCC catalysts responsible for the production of gasoline-range molecules is zeolite Y.19 The structure of zeolite Y, shown in Fig. 10, has a 3-D pore system, in which pores of ∼7.3 Å connect larger (13 Å in diameter) cages, which are known as the supercages of this zeolite.

MeSH