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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.


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X-ray nanotomography study of an E-cat catalyst particle, revealing the relative spatial distributions of Ni and Fe and their effect on the macropore structure and accessibility. A sub-volume of 16.6 × 16.6 × 10 μm3 was selected (b) out of the entire catalyst particle of 44.8 × 52.7 × 51.2 μm3 in size (a), including the relative Fe and Ni distributions. Permeability calculation was applied on this sub-volume (c). Mass transport through the sub-volume along the selected axis (red arrow) is visualized using the velocity field of the fluid. The streamlines indicate the magnitude of the velocity field where red represents the highest velocity (i.e., where the pore space constriction is the largest) and blue indicates the lowest velocity. (Reproduced with permission from ref. 170, Copyright American Chemical Society, 2015).
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fig23: X-ray nanotomography study of an E-cat catalyst particle, revealing the relative spatial distributions of Ni and Fe and their effect on the macropore structure and accessibility. A sub-volume of 16.6 × 16.6 × 10 μm3 was selected (b) out of the entire catalyst particle of 44.8 × 52.7 × 51.2 μm3 in size (a), including the relative Fe and Ni distributions. Permeability calculation was applied on this sub-volume (c). Mass transport through the sub-volume along the selected axis (red arrow) is visualized using the velocity field of the fluid. The streamlines indicate the magnitude of the velocity field where red represents the highest velocity (i.e., where the pore space constriction is the largest) and blue indicates the lowest velocity. (Reproduced with permission from ref. 170, Copyright American Chemical Society, 2015).

Mentions: Meirer and co-workers170 have been using element-specific X-ray nano-tomography to investigate the 3D structure of a whole individual FCC catalyst particle at high spatial resolution and in a non-invasive manner. This was done by using a full-field X-ray absorption mosaic nano-tomography set-up at beamline 6.2 of the Stanford Synchrotron Radiation Lightsource, providing better than 30 nm 2D spatial resolution. With this instrumentation it was possible to map the relative spatial distribution of the metal contaminants, Ni and Fe, and correlate these distributions to porosity and permeability changes of an E-cat catalyst particle. Both Ni and Fe were found to accumulate in the outer layers of the catalyst particle, although Ni was found to penetrate in the deeper layers than Fe, effectively decreasing the porosity by clogging the macropores and thereby restricting access into the catalyst particle. This is illustrated in Fig. 23, which shows the permeability calculation of a sub-volume of the E-cat particle of 16.6 × 16.6 × 10 μm3 in size, in which Fe is found in lower concentrations than at the outer catalyst surface, while Ni is more concentrated at the top of the selected sub-volume (Fig. 23b). By simulating the fluid flow through this sub-volume, two distinct effects could be revealed. First, the authors observed a constriction of flow where Ni is present, indicated by the high velocity (red area, Fig. 23c) fluid flow through small cross sectional areas. Elsewhere in the region, with little to no Ni, flow is less inhibited (blue streamlines, Fig. 23c). Secondly, there were areas with large Ni content, which were totally inaccessible because the Ni is clogging some macropores completely.


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

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

X-ray nanotomography study of an E-cat catalyst particle, revealing the relative spatial distributions of Ni and Fe and their effect on the macropore structure and accessibility. A sub-volume of 16.6 × 16.6 × 10 μm3 was selected (b) out of the entire catalyst particle of 44.8 × 52.7 × 51.2 μm3 in size (a), including the relative Fe and Ni distributions. Permeability calculation was applied on this sub-volume (c). Mass transport through the sub-volume along the selected axis (red arrow) is visualized using the velocity field of the fluid. The streamlines indicate the magnitude of the velocity field where red represents the highest velocity (i.e., where the pore space constriction is the largest) and blue indicates the lowest velocity. (Reproduced with permission from ref. 170, Copyright American Chemical Society, 2015).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig23: X-ray nanotomography study of an E-cat catalyst particle, revealing the relative spatial distributions of Ni and Fe and their effect on the macropore structure and accessibility. A sub-volume of 16.6 × 16.6 × 10 μm3 was selected (b) out of the entire catalyst particle of 44.8 × 52.7 × 51.2 μm3 in size (a), including the relative Fe and Ni distributions. Permeability calculation was applied on this sub-volume (c). Mass transport through the sub-volume along the selected axis (red arrow) is visualized using the velocity field of the fluid. The streamlines indicate the magnitude of the velocity field where red represents the highest velocity (i.e., where the pore space constriction is the largest) and blue indicates the lowest velocity. (Reproduced with permission from ref. 170, Copyright American Chemical Society, 2015).
Mentions: Meirer and co-workers170 have been using element-specific X-ray nano-tomography to investigate the 3D structure of a whole individual FCC catalyst particle at high spatial resolution and in a non-invasive manner. This was done by using a full-field X-ray absorption mosaic nano-tomography set-up at beamline 6.2 of the Stanford Synchrotron Radiation Lightsource, providing better than 30 nm 2D spatial resolution. With this instrumentation it was possible to map the relative spatial distribution of the metal contaminants, Ni and Fe, and correlate these distributions to porosity and permeability changes of an E-cat catalyst particle. Both Ni and Fe were found to accumulate in the outer layers of the catalyst particle, although Ni was found to penetrate in the deeper layers than Fe, effectively decreasing the porosity by clogging the macropores and thereby restricting access into the catalyst particle. This is illustrated in Fig. 23, which shows the permeability calculation of a sub-volume of the E-cat particle of 16.6 × 16.6 × 10 μm3 in size, in which Fe is found in lower concentrations than at the outer catalyst surface, while Ni is more concentrated at the top of the selected sub-volume (Fig. 23b). By simulating the fluid flow through this sub-volume, two distinct effects could be revealed. First, the authors observed a constriction of flow where Ni is present, indicated by the high velocity (red area, Fig. 23c) fluid flow through small cross sectional areas. Elsewhere in the region, with little to no Ni, flow is less inhibited (blue streamlines, Fig. 23c). Secondly, there were areas with large Ni content, which were totally inaccessible because the Ni is clogging some macropores completely.

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.


Related in: MedlinePlus