Temperature-programmed reduction of metal-contaminated fluid catalytic cracking (FCC) catalysts

Bayraktar, Oğuz

doi:10.1016/j.apcata.2003.10.013

“…The oxidation state of metals can be determined by X-ray photoelectron spectroscopy (XPS) [107], X-ray absorption [115] or temperature-programmed reduction (TPR) [106,116]. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) determine the morphology of the catalyst surface.…”

Section: Characterizationmentioning

confidence: 99%

Fluid Catalytic Cracking

Cheng¹,

Habib²,

Rajagopalan³

et al. 2008

Handbook of Heterogeneous Catalysis

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The sections in this article are Introduction and Overview History FCC Today Position in a Modern Petroleum Refinery Environmental Issues FCC Unit Hardware and Operations Unit Types Heat Balance Modes of Operation Regeneration Mode—Partial Burn vs. Full Burn Resid Processing Petrochemical Mode (Light Olefins) FCC Feeds Sources and Trends Molecular Types Characterization Effects on FCC Unit Operation Conradson Carbon and Feed Heaviness Feedstock Composition Metals: Ni , V , Na and Fe Sulfur Nitrogen The Chemistry of Catalytic Cracking Carbocations Formation of Carbocations Isomerization Reactions CarbonCarbon Bond Breaking by Beta‐Scission Hydride Transfer (also Referred to as Hydrogen Transfer) Heteroatom Chemistry: Sulfur FCC Catalysts Description and Formulation Zeolite Component Zeolite Modifications Zeolite Activity and Selectivity Effects Matrix Commercial Matrices Effect of Matrix on Selectivity Characterization ZSM ‐5 Additives FCCU Environmental Emissions Controls Overview—Catalyst Versus Hardware Particulates Carbon Monoxide ( CO ) Sulfur Oxides ( SO x ) Nitrogen Oxides ( NO x ) Laboratory Evaluations and Pilot Plant Testing Accelerated Aging of Catalysts Simulation of Metals Poisoning Reactor Types—Fixed Bed vs. Fluid Bed vs. Transport Phase Temperature Profile and Isothermal vs. Adiabatic Testing Summary and Future Trends in Catalytic Cracking

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“…As reported in the previous study [7], the TPR spectra of highly contaminated equilibrium catalyst, ECat-HIGH, before and after ex situ hydrogen pretreatment allow us to understand the effect of pretreatment on the observed catalyst activity. Normally, A temperature-programmed reduction study of equilibrium FCC catalysts has shown three hydrogen-consumption peaks associated with contaminant metals is produced by the reduction of several components in the catalyst.…”

Section: Hydrogen Transfer Reactionsmentioning

confidence: 99%

“…Highly dispersed vanadium contributes to the low-temperature peak, located near 510 • C. A high-temperature peak, located near 800 • C, is produced by reduction of nickel-aluminate type compounds. An intermediate-temperature peak, located near 690 • C, appears to be related to some form of vanadium compound [7].…”

Section: Hydrogen Transfer Reactionsmentioning

confidence: 99%

“…Nickel in +2 valance on a surface like alumina forms nickel aluminate [11,12]. In the previous paper [7], it has been shown that after several reduction-oxidation cycles nickel forms nickel aluminate type compounds which appear as a high temperature peak in the temperature-programmed reduction (TPR) profile. Cadet et al [11] have shown that nickel aluminate can also promote dehydrogenation reactions, although its dehydrogenation rate was found to be less than the rate for nickel metal.…”

Section: Hydrogen Transfer Reactionsmentioning

confidence: 99%

“…They are named ECat-LOW, ECat-INT, and ECat-HIGH based on their contaminant-metals concentration. Additional information on these catalysts is given in the previous paper [7]. Mainly, ECat-LOW contains 300 mg kg −1 nickel and 700 mg kg −1 vanadium; ECat-INT contains 900 mg kg −1 nickel and 1700 mg kg −1 vanadium; ECat-HIGH contains 2600 mg kg −1 nickel and 6700 mg kg −1 vanadium.…”

Section: Fcc Catalysts and Catalyst Pretreatmentmentioning

confidence: 99%

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Effect of pretreatment on the performance of metal-contaminated fluid catalytic cracking (FCC) catalysts

Bayraktar

¹

,

Kugler

²

2004

Applied Catalysis A: General

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Effects of both hydrogen and methane pretreatment on the performance of metal-contaminated equilibrium fluid catalytic cracking (FCC) catalysts from a refinery were investigated. Both hydrogen and methane pretreatment at 700• C were proven to be advantageous since the yields of hydrogen and coke from sour imported gas oil (SIHGO) cracking decrease while light cycle oil (LCO) and gasoline yields increase. The catalysts pretreated with hydrogen have shown slightly better improvement than the catalysts pretreated with methane. The decrease in the yields of hydrogen and coke was attributed to decrease in the dehydrogenation activity of vanadium oxides, which are present at high concentrations on the equilibrium FCC catalysts. This decrease in dehydrogenation activity after the pretreatment was also confirmed by low hydrogen-to-methane ratio. It was found that reduced vanadium has lower dehydrogenation activity since it produces less coke and hydrogen compared to oxidized vanadium.Hydrogen transfer reactions were evaluated by measuring C 4 paraffin-to-C 4 olefin ratios. Hydrogen transfer reactions decreased with increasing metal concentration. Both hydrogen and methane pretreatment caused the hydrogen transfer reactions to increase. Improved hydrogen transfer reactions caused an increase in the gasoline range products.

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Equilibrium catalyst from a fluidized catalytic cracking unit separated by metal content by using carbon nanotubes and a biphasic system

Briggs

¹

,

Crossley

²

2021

AIChE Journal

0

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During fluid catalytic cracking (FCC) operations FCC catalyst particles become contaminated with various metals. These metals impact FCC performance and currently requires equilibrium catalyst (ECAT) mixtures consisting of a blend of FCC particles with a time spent in the reactor ranging from minutes to several months to be continuously extracted and sold as low value products or sent to landfills. Here a unique method to recycle FCC ECAT particles is presented, which separates ECAT particles by metal content by synthesizing carbon nanotubes and nanofibers on the ECAT particles surface and using a biphasic system. ECAT with low metal content can be sent back to the FCC unit for further use while ECAT with high metal content can be used for other purposes. Further, we show these treated ECAT materials of high metals content will absorb oil on the surface of water and may prove useful for oil spill clean‐up applications.

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Temperature-programmed reduction of metal-contaminated fluid catalytic cracking (FCC) catalysts

Cited by 27 publications

References 14 publications

Fluid Catalytic Cracking

Fluid Catalytic Cracking

Effect of pretreatment on the performance of metal-contaminated fluid catalytic cracking (FCC) catalysts

Equilibrium catalyst from a fluidized catalytic cracking unit separated by metal content by using carbon nanotubes and a biphasic system

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