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

Vogt ET, Weckhuysen BM - Chem Soc Rev (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

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.

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.

No MeSH data available.


FE-SEM images from untreated (top) and mesostructured (bottom) zeolite Y crystals. Scale bars: (a) 1 μm; (b and c) 500 nm; (d) 200 nm. (Reproduced with permission from ref. 83, Copyright Wiley-VCH, 2014).
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fig19: FE-SEM images from untreated (top) and mesostructured (bottom) zeolite Y crystals. Scale bars: (a) 1 μm; (b and c) 500 nm; (d) 200 nm. (Reproduced with permission from ref. 83, Copyright Wiley-VCH, 2014).

Mentions: Hansen et al.82 describe the introduction of uniform mesopores in the size range of about 4 nm, or about 6 times larger than the micropores in the host lattice of the zeolite (see Fig. 19), by a post-synthesis chemical treatment.83,105 We will expand a bit on this work, as it directly concerns an application in FCC. The authors observe a lower bottoms yield at constant coke, and improved middle distillate over bottoms selectivity in ACE testing. A similar effect is seen for the gasoline over LPG selectivity, since the optimum in the series pathway network is shifted to higher molecular weight. The post-synthesis treatment in this technology appears to amount to a re-crystallization of the zeolite in alkali (pH 9–11) in the presence of cetyl-trimethyl-ammonium-bromide (CTAB) at 150 °C. The starting zeolite in the original process already has a quite high silica-to-alumina ratio of about 30, lower SAR zeolites apparently need an acid pretreatment before they are suitable for post-treatment.106 Carbon residue from the template is removed by careful calcination at 550 °C. Following the treatment, the authors do not observe any octahedrally coordinated Al in the NMR spectrum, and terminal silanol vibrations at 3740 cm–1 also disappear, both indicating a lattice without too many irregularities. The vibration of the Brønsted acid site at 3640 cm–1 seems to increase compared to the parent material, as does a vibration at ∼3540 cm–1, on which the authors do not comment. TPD of ammonia shows that the mesostructured material has about the same number of acid sites as normal zeolite US-Y. The zeolites were tested after being introduced in FCC-matrices, and steam-deactivated. At constant conversion, lower bottoms- and coke-make, and higher gasoline and middle distillate yields are observed.


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

Vogt ET, Weckhuysen BM - Chem Soc Rev (2015)

FE-SEM images from untreated (top) and mesostructured (bottom) zeolite Y crystals. Scale bars: (a) 1 μm; (b and c) 500 nm; (d) 200 nm. (Reproduced with permission from ref. 83, Copyright Wiley-VCH, 2014).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4594121&req=5

fig19: FE-SEM images from untreated (top) and mesostructured (bottom) zeolite Y crystals. Scale bars: (a) 1 μm; (b and c) 500 nm; (d) 200 nm. (Reproduced with permission from ref. 83, Copyright Wiley-VCH, 2014).
Mentions: Hansen et al.82 describe the introduction of uniform mesopores in the size range of about 4 nm, or about 6 times larger than the micropores in the host lattice of the zeolite (see Fig. 19), by a post-synthesis chemical treatment.83,105 We will expand a bit on this work, as it directly concerns an application in FCC. The authors observe a lower bottoms yield at constant coke, and improved middle distillate over bottoms selectivity in ACE testing. A similar effect is seen for the gasoline over LPG selectivity, since the optimum in the series pathway network is shifted to higher molecular weight. The post-synthesis treatment in this technology appears to amount to a re-crystallization of the zeolite in alkali (pH 9–11) in the presence of cetyl-trimethyl-ammonium-bromide (CTAB) at 150 °C. The starting zeolite in the original process already has a quite high silica-to-alumina ratio of about 30, lower SAR zeolites apparently need an acid pretreatment before they are suitable for post-treatment.106 Carbon residue from the template is removed by careful calcination at 550 °C. Following the treatment, the authors do not observe any octahedrally coordinated Al in the NMR spectrum, and terminal silanol vibrations at 3740 cm–1 also disappear, both indicating a lattice without too many irregularities. The vibration of the Brønsted acid site at 3640 cm–1 seems to increase compared to the parent material, as does a vibration at ∼3540 cm–1, on which the authors do not comment. TPD of ammonia shows that the mesostructured material has about the same number of acid sites as normal zeolite US-Y. The zeolites were tested after being introduced in FCC-matrices, and steam-deactivated. At constant conversion, lower bottoms- and coke-make, and higher gasoline and middle distillate yields are observed.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

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.

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.

No MeSH data available.