Initial coke deposition on hydrotreating catalysts. Part 1. Changes in coke properties as a function of time on stream

Matsushita, Koichi; Hauser, A.; Marafi, Abdulazem; Koide, Ryutaro; Stanislaus, A.

doi:10.1016/j.fuel.2003.10.015

Cited by 66 publications

(60 citation statements)

References 29 publications

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“…Indeed, the baseline of the IR signal is seen to be shifted toward high absorbance during the experiment but a tilt is also observable ( Figure 8). This is due to the solid coke particles in the stream and this phenomenon has already been observed in literature [39]- [42]. Because no calibration has been done for the coke quantification, it is difficult to link quantitatively this signal change to the carbon deposit.…”

Section: Figure 7 Should Be Placed Herementioning

confidence: 82%

Real-time method for the identification and quantification of hydrocarbon pyrolysis products: Part II. Application to transient pyrolysis and validation by numerical simulation

Gascoin

Abraham

Gillard

et al. 2011

Journal of Analytical and Applied Pyrolysis

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A real-time quantification Infra Red method has been developed with a gas cell to determine the composition of hydrocarbon pyrolysis products. The aim is to chemically characterise the fuel decomposition in case of regenerative cooling. The method can be extended to a large variety of applications. A transient analysis of the method behaviour is conducted to estimate its capacity to be applied to unsteady conditions (one measure per second), which can be encountered in cooling activity and unsteady processes. 2/38 obtained on gas cell measurements is found to be correct over 10 wt% to 20 wt.% of gasification rate and very satisfactory over 60 wt.% but this depends on the species. An extension of the method has been developed with a dedicated online cell to be specifically applied to supercritical and multiphase flows. The quantification of the gas phase in the pyrolysis mixture in case of biphasic flow is proposed and validated with an uncertainty around 3 wt.%. The coke formation is monitored as a function of time and its quantification is even tested with 50 % of uncertainty after a numerical calibration with respect to simulation.

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Section: Figure 7 Should Be Placed Herementioning

confidence: 82%

Real-time method for the identification and quantification of hydrocarbon pyrolysis products: Part II. Application to transient pyrolysis and validation by numerical simulation

Gascoin

Abraham

Gillard

et al. 2011

Journal of Analytical and Applied Pyrolysis

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“…[23][24][25][26] The main feature of this organic matter is its high reactivity towards oxidation as seen in temperatureprogrammed oxidation experiments. 23,25,26 Soluble coke contains more hydrogen than the insoluble one. As usual, solvents are not effective in removing insoluble coke.…”

Section: Removal Of Soluble Cokementioning

confidence: 99%

“…Removal of soluble coke (more hydrogenated) reduces risk of ignition of insoluble coke. 23,25,26 The presence of soluble coke and foulant elements (over the catalyst surface) may favor local flashing zones, thus forming refractory compounds. 2,28 Component interaction may occur on overheating.…”

Section: Removal Of Insoluble Cokementioning

confidence: 99%

The importance of pre-treatment of spent hydrotreating catalysts on metals recovery

et al. 2011

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Recebido em 25/1/10; aceito em 2/6/10; publicado na web em 17/9/10 This work describes a three-step pre-treatment route for processing spent commercial NiMo/Al 2 O 3 catalysts. Extraction of soluble coke with n-hexane and/or leaching of foulant elements with oxalic acid were performed before burning insoluble coke under air. Oxidized catalysts were leached with 9 mol L -1 sulfuric acid. Iron was the only foulant element partially leached by oxalic acid. The amount of insoluble matter in sulfuric acid was drastically reduced when iron and/or soluble coke were previously removed. Losses of active phase metals (Ni, Mo) during leaching with oxalic acid were compensated by the increase of their recovery in the sulfuric acid leachate.

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“…Several techniques have been reported to be effective for such a purpose: solvent extraction, 7 temperature programmed techniques, 7,8 FTIR, 7 laser Raman spectroscopy, 9 13 C (CP/MAS) NMR 10,11 ; Pulsed field gradient-nuclear magnetic resonance. 12 The isomerization of alkanes on acid catalysts is always accompanied by the coke deposition.…”

Section: Introductionmentioning

confidence: 99%

“…Most of the studies consider only the long-term aged catalysts and studies on initial coke formation are scarce. 7 The addition of hydrogen is improving the isomerization catalyst stability. For sulfated zirconia catalysts, Garin et al 19 have observed that hydrogen prevents coke formation even in the absence of platinum.…”

Section: Introductionmentioning

confidence: 99%

WO_x‐CeO₂ and WO_x‐Nb₂O₅ catalysts deactivation during hexane isomerization

Mamede¹,

Payen²,

Granger³

et al. 2008

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com).Two series of WO x -CeO 2 catalysts containing 10, 12, and 15 wt % W were prepared by co-precipitation and incipient wetness impregnation using a reported procedure. WO x -Nb 2 O 5 catalysts with the same amount of W were prepared by co-precipitation starting from an aqueous solution of ammonium niobium oxalate and ammonium metatungstate with ammonia, until reaching pH 7. After calcining for 3 h in static air at 973 K, the deactivation of the catalysts was investigated using isomerization of hexane as probe reaction at temperatures in the range 393-513 K, both in the absence and in the presence of hydrogen. In-situ Raman spectra during deactivation were recorded as well. The deactivation rate was fitted by an empirical Voorhies equation: R 5 m t 2n , where the values of n correlated very well with the mass loss determined from TG analysis.

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Initial coke deposition on hydrotreating catalysts. Part 1. Changes in coke properties as a function of time on stream

Cited by 66 publications

References 29 publications

Real-time method for the identification and quantification of hydrocarbon pyrolysis products: Part II. Application to transient pyrolysis and validation by numerical simulation

Real-time method for the identification and quantification of hydrocarbon pyrolysis products: Part II. Application to transient pyrolysis and validation by numerical simulation

The importance of pre-treatment of spent hydrotreating catalysts on metals recovery

WO_x‐CeO₂ and WO_x‐Nb₂O₅ catalysts deactivation during hexane isomerization

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Initial coke deposition on hydrotreating catalysts. Part 1. Changes in coke properties as a function of time on stream

Cited by 66 publications

References 29 publications

Real-time method for the identification and quantification of hydrocarbon pyrolysis products: Part II. Application to transient pyrolysis and validation by numerical simulation

Real-time method for the identification and quantification of hydrocarbon pyrolysis products: Part II. Application to transient pyrolysis and validation by numerical simulation

The importance of pre-treatment of spent hydrotreating catalysts on metals recovery

WOx‐CeO2 and WOx‐Nb2O5 catalysts deactivation during hexane isomerization

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WO_x‐CeO₂ and WO_x‐Nb₂O₅ catalysts deactivation during hexane isomerization