Deactivation of hydrodemetallization catalyst by pore plugging

Galiasso, R.; Blanco, Raquel; González, Carlos; Quinteros, N.

doi:10.1016/0016-2361(83)90034-0

Cited by 34 publications

(16 citation statements)

References 4 publications

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“…It was observed that an increase of the temperature favorably affects the heteroatom-and metal-removal reactions and that desulfuration reactions show the highest reaction rates, as observed by Galiasso et al 32,38 The removal rates decreased in the order HDS > HDN > HDV > HDNi. Most investigations 27,28,30,31,[39][40][41][42][43][44][45][46][47] have revealed that vanadium-removal rates exceed those of nickel in petroleum residua.…”

Section: Hydroprocessing Of a Maya Residuementioning

confidence: 73%

Hydroprocessing of a Maya Residue. Intrinsic Kinetics of Sulfur-, Nitrogen-, Nickel-, and Vanadium-Removal Reactions

and

Martínez

1999

Energy Fuels

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A residue from a Maya crude was processed in a hydrotreating unit with a continuous stirred tank reactor at high temperatures (375-415 °C) and hydrogen pressures (10-15 MPa). A commercial guard-bed demetalation catalyst Ni-Mo supported on γ-Al 2 O 3 was used. In this paper, the intrinsic kinetics of the sulfur-, nitrogen-, nickel-, and vanadium-removal reactions are reported. The sulfur-removal reactions fit second-order kinetics, the nitrogen-removal reactions half-order kinetics, the nickel-removal reactions first-order kinetics, and the vanadium-removal reactions half-order kinetics. The nickel-removal reactions showed the highest value for the activation energy. The sulfur-removal reactions were the only ones that had a dependence on the hydrogen pressure in every range of hydrogen pressures studied, 10-15 MPa, and a kinetic order of 0.4 has been observed. For nitrogen-, nickel-, and vanadium-removal reactions, an increase of the pseudokinetic constants was only observed between 10 and 12.5 MPa. The percentages of sulfur-removal range from 22% to 79.3%, nitrogen conversion from 3.7% to 50.9%, nickel conversion from 32.1% to 98.8%, and vanadium conversion from 40.1% to 99.7% at 375 °C, 10 MPa, and 7.1 L/h g cat and 415 °C, 12.5 MPa, and 3.3 L/h g cat . The relationships between the percentages of sulfur-removal and metal-removal were studied.

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Section: Hydroprocessing Of a Maya Residuementioning

confidence: 73%

Hydroprocessing of a Maya Residue. Intrinsic Kinetics of Sulfur-, Nitrogen-, Nickel-, and Vanadium-Removal Reactions

and

Martínez

1999

Energy Fuels

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“…In practice, the presence of catalyst and/or reducing atmosphere may facilitate decomposition of the porphyrin structure through HDM reactions and catalyst-facilitated decomposition is suggested by the presence of the metal deposits observed 3.8 cm deep into the catalyst bed during the cyanobacteria run. Metal deposition may deactivate the catalyst via a pore plugging mechanism48 and as the catalyst deactivates, porphyrin-rich HTL biocrude may traverse further into the catalyst bed prior to decomposition and ultimate metal deposition. More testing is required to understand the thermal versus environmentally-facilitated (i.e., catalyst presence and reducing atmosphere) porphyrin decomposition mechanism.Additionally, the deposition of iron in the top 5 cm of either catalyst bed indicates that iron-porphyrins deposit at a temperature range from ~340°C and as high as ~360°C.…”

mentioning

confidence: 99%

Impact of iron porphyrin complexes when hydroprocessing algal HTL biocrude

Jarvis

Sudasinghe

Albrecht

et al. 2016

Fuel

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We apply Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) for direct characterization of iron-porphyrins in hydrothermal liquefaction (HTL) biocrude oils derived from two algae: Tetraselmis sp. and cyanobacteria. The iron porphyrin compounds are shown to cause catalyst bed plugging during hydroprocessing due to iron deposition. Inductively-coupled plasma optical emission spectrometry (ICP-OES) was utilized for iron quantitation in the plugged catalyst beds formed through hydroprocessing of the two HTL biocrudes and identifies an enrichment of iron in the upper five centimeters of the catalyst bed for Tetraselmis sp. (Fe=100,728 ppm) and cyanobacteria (Fe=115,450 ppm). Direct infusion FT-ICR MS analysis of the two HTL biocrudes with optimized instrument conditions facilitates rapid screening and identification of iron porphyrins without prior chromatographic separation. With FT-ICR MS we identify 138 unique iron porphyrin compounds in the two HTL biocrudes that have similar carbon number and double bond equivalent distributions to the metal porphyrins (e.g. Ni and V) reported for petroleum. No iron porphyrins are observed in the cyanobacteria HTL biocrude after hydroprocessing, which indicates that iron porphyrin structures in the HTL biocrude are degraded during hydrotreatment. Hydrodemetallization reactions that occur through hydroprocessing of HTL biocrudes could be responsible for the decomposition of iron porphyrin structures leading to metal deposition in the catalyst bed that result in catalyst deactivation and bed plugging, and must be addressed for effective upgrading of algal HTL biocrudes.

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“…Nevertheless, coke formatting and its eventual equilibrium have been argued to be much shorter than the initial decay period lasting 1 to 2 months or a quarter of the effective lifetime of the catalysts [4,10,17,30]. The latest studies find that coke preferentially deposits on the alumina support rather than on the active phase [15,19,31,33,34], suggesting that coking does not foul the active sites substantially.…”

Section: Introductionmentioning

confidence: 97%

“…Generally it is acknowledged that carbonaceous deposits or fouling by coke may play a role in the initial stage, depending on the composition of feeds, the characteristics of catalysts, and the severity of reactions [1,2,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Noticeably about 10-30 wt% carbonaceous deposits based on the fresh catalyst accumulate on the surface within at most the first 2 weeks of operation, and then attains a quasi-steady state [1,11,12,15,16,[18][19][20].…”

Section: Introductionmentioning

confidence: 99%