Investigation of carbonaceous compounds deposited on NiMo catalyst used for ultra-deep hydrodesulfurization of gas oil by means of temperature-programmed oxidation and Raman spectroscopy

Koizumi, Naoto; Urabe, Yoshihisa; Inamura, Kentaro; Itoh, Takashi; Yamada, Masahito

doi:10.1016/j.cattod.2005.07.172

Cited by 29 publications

(18 citation statements)

References 8 publications

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“…This difference is presumably due to the different types of coke on the catalysts. Koizumi et al reported that amorphous coke changed into graphite-like coke with increasing time on stream [11]. The increase in the weight of the carbon deposit and the aromaticity of the coke seen for LCO contained in MIX-D in this work is consistent with these previously reported results.…”

Section: Characteristics Of Deposits On the Catalystsupporting

confidence: 95%

“…5). Two bands were observed in the Raman spectra; the sharp band observed around 1580 cm À1 indicates graphitization and is referred to as the G-band [11], and the broad band at around 1360 cm À1 indicates the defect structure and is referred to as the D-band [12]. The ratio of G-band to D-band intensities is used to evaluate the regularity of the carbon structure.…”

Section: Characteristics Of Deposits On the Catalystmentioning

confidence: 99%

“…Therefore, an investigation of the hydrocarbon and nitrogen-containing hydrocarbons in the feedstock is significant, as carbonaceous deposits on the catalyst are presumed to cause the deactivation of HDS activity in the gas oil HDS unit [9,10]. Several analytical methods have been used to characterize these carbonaceous compounds, including Raman spectroscopy [11,12], temperature programmed oxidation [12], and electron energy-loss spectroscopy in transmission electron microscopy (TEM-EELS) [13,14].…”

Section: Introductionmentioning

confidence: 99%

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Effect of basic nitrogen compounds on gas oil hydrodesulfurization and deposit formed on the catalyst

Koide

Iwanami

Konishi

et al. 2015

Fuel

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Section: Characteristics Of Deposits On the Catalystsupporting

confidence: 95%

Section: Characteristics Of Deposits On the Catalystmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of basic nitrogen compounds on gas oil hydrodesulfurization and deposit formed on the catalyst

Koide

Iwanami

Konishi

et al. 2015

Fuel

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“…As the supply of low sulfur crude decreases, refineries are processing crude with high sulfur content meanwhile environmental regulation is becoming more and more restrictive for the gas emissions from diesel vehicles (50 wt ppm-S in Europe and Japan in 2005 [1,2]). Consequently the necessity to develop efficient hydrodesulfurization (HDS) catalysts is evident.…”

Section: Introductionmentioning

confidence: 99%

High activity Ni/MoS2 catalysts obtained from alkylthiometalate mixtures for the hydrodesulfurization of dibenzothiophene

et al. 2007

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An efficient method for improving the catalytic properties of unsupported Ni/MoS 2 catalysts is mixing thiometalate precursors applying the appropriate precursors and thermal conditions. High active catalysts for the hydrodesulfurization (HDS) of dibenzothiophene (DBT) are prepared by the controlled decomposition of physical mixtures of Ni(diethylentriamine) 2 MoS 4 (NDTA-TM) and [(Propyl) 4 N)] 2 MoS 4 (TPA-TM). The catalysts with a higher content of NDTA-TM are very active with a high selectivity for the direct desulfurization pathway (DDS) due to the synergistic effect of nickel. In addition the presence of a large amount of carbon may produce single-slabs of nickel promoted carbon containing molybdenum sulfides. The activity enhancement is attributed to an increased number of NiMoS active sites originated by the chemical interaction between the precursors NDTA-TM and TPA-TM during the mixing procedure. Furthermore, the carbon content in the final products is related to the enhancement of the activity and the preference of the DDS pathway. The controlled decomposition of mixtures of NDTA-TM + TPA-TM yields catalysts which are about twofold more active than an industrial NiMo/Al 2 O 3 catalyst. This improvement may be attributed to an intense interaction of the precursors during the synthesis causing a re-dispersion of nickel atoms from NDTA-TM over the surface of carbon containing molybdenum sulfide provided by the precursor TPA-TM, increasing the amount of active sites. The catalysts from mixtures of (NH 4 ) 2 MoS 4 (A-TM) and NDTA-TM behave similarly to the pure precursors.

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“…The band G originates from the vibrations in the graphene planes of hybridization sp 2 of carbon atoms in the aromatic structures. As commonly known [41], the band G becomes sharper and more intensive, e.g., for graphite [42] with the increasing degree of carbon matter graphitization, i.e., for more ordered aromatic structures. However, the band D, typically observed at 1350 cm -1 , is characteristic of disordered graphene structures of the carbon hybridization sp 3 which is characteristic of diamond structure.…”

Section: Thermal Analysismentioning

confidence: 67%

Active carbons from waste biochars

Skubiszewska–Zięba

Charmas

Kołtowski

et al. 2017

J Therm Anal Calorim

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Studies of preparation of active carbons of good structural and adsorption properties based on commercial biochars, which become wastes after removal of precious volatile components from natural raw materials of different origin, i.e., from wheat straw, Miscanthus grass, walnut shells, and energetic willow were carried out. There was applied the physical activation under atmospheric pressure in the fluidal reactor using CO 2 or overheated steam and in the closed system in the high pressure microwave reactor under hydrothermal conditions. The obtained active carbons were investigated by means of adsorption (N 2 ), thermal (TG, DTG, DTA), spectral (Raman spectra) as well as electron microscopy methods. The adsorbents obtained as a result of modification were characterized by a welldeveloped porous structure and greater thermal resistance compared to the initial biochars.

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Investigation of carbonaceous compounds deposited on NiMo catalyst used for ultra-deep hydrodesulfurization of gas oil by means of temperature-programmed oxidation and Raman spectroscopy

Cited by 29 publications

References 8 publications

Effect of basic nitrogen compounds on gas oil hydrodesulfurization and deposit formed on the catalyst

Effect of basic nitrogen compounds on gas oil hydrodesulfurization and deposit formed on the catalyst

High activity Ni/MoS2 catalysts obtained from alkylthiometalate mixtures for the hydrodesulfurization of dibenzothiophene

Active carbons from waste biochars

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