Structure and formation of shot coke ? a microscopy study

Marsh, H.; Calvert, C.; Bacha, John D.

doi:10.1007/bf00555923

Cited by 37 publications

(31 citation statements)

References 9 publications

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“…In addition, it has been reported that the type of coke formed is mainly dependent on feed properties; in particular, high asphaltene and metal content leads to shot-type coke 22,24,86 . This can also be affected by Low Temperature Oxidation (LTO), producing shiny, very hard, and more difficult to burn coke.…”

Section: Effect Of Dispersed Catalysts On Type Of Formed Cokementioning

confidence: 99%

Effectiveness of Different Transition Metal Dispersed Catalysts for In Situ Heavy Oil Upgrading

Al-Marshed

Hart

Leeke

et al. 2015

Ind. Eng. Chem. Res.

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Ultradispersed particles of size less than 100 nm for in situ catalytic upgrading have been reported to outperform the augmented catalytic upgrading achieved by incorporating pelleted refinery catalyst to the horizontal production well of the THAI process. Hydroconversion of heavy oil was carried out in a stirred batch reactor at 425˚C, 50 bar (initial H 2 pressure), 900 rpm and 60 min reaction time using a range of unsupported transition metal (Mo, Ni and Fe) catalysts. The effect of metal nanoparticles (NPs) was evaluated in terms of product distribution, physical properties and product quality. The produced coke and recovered catalysts were also studied. The levels of API gravity and viscosity of the upgraded oils observed with the NPs was approximately 21˚API and 108 cP compared with thermal cracking alone (24˚API and 53.5 cP), this moderate upgrade with NPs is due to the lack of cracking functionality offered by supports such as zeolite, alumina or silica. However, it was found that the presence of dispersed NPs significantly suppressed coke formation 4.4 wt% (MoS 2 ), 5.7 wt% (NiO) and 6.8 wt% (Fe 2 O 3 ) compared to 12 wt% obtained with thermal cracking alone. The results also showed that with dispersed unsupported metal NPs in sulfide form the middle distillate (177-343 ˚C) of the upgraded oil was improved particularly MoS 2 which gave 50 wt% relative to 43 wt% (thermal cracking) and 28 wt% (feed oil). The middle distillate yields for Fe 2 O 3 and NiO are 47 wt% and 49 wt%, respectively. Hence, iron and nickel-based unsupported NPs showed similar activity when compared to MoS 2 . The cost and availability of iron-based catalysts compared to Ni and Mo counterpart for heavy oil upgrading are advantages that may justify its preference.Furthermore, the X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis showed that introducing dispersed catalysts to the upgrading helped to produce sponge-type coke which could be used as industrial fuel compared to shot-type obtained upon thermal cracking.

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Section: Effect Of Dispersed Catalysts On Type Of Formed Cokementioning

confidence: 99%

Effectiveness of Different Transition Metal Dispersed Catalysts for In Situ Heavy Oil Upgrading

Al-Marshed

Hart

Leeke

et al. 2015

Ind. Eng. Chem. Res.

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“…nitrogen, sulphur and oxygen and other associated metals. Presumably there exists a sufficiently high content of aliphatic carbon and hydrogen and this could lead to significant volatile evolution within the coking drum [4].…”

Section: C)mentioning

confidence: 99%

“…Shot coke tends to be more isotropic than other types of coke and its optical texture is of fine-grained mosaic (~1μm dia.) [4]. The carbon in shot coke is in the form of ribbon and lenticular/granular anisotropic domains arranged in concentric patterns.…”

Section: C)mentioning

confidence: 99%

“…While low grindability cokes are preferred since such cokes yield calcined coke which exhibits a very high vibrated bulk density which is desirable in an aluminium prebaked anode, good bonding with binder coal tar pitch is prevented by the slickness of the outer layer of the shot spheres, their lack of permeability and porosity and dissimilarity of the outer needle coke layer of the shot sphere which has a very low coefficient of thermal expansion and the interior core of the sphere which, being isotropic, has a very high coefficient of thermal expansion. The higher coefficient of thermal expansion of the shot coke is also thought to cause thermal shock cracking of the anode when it is set in a hot cell [1][2][3][4].…”

Section: C)mentioning

confidence: 99%

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Thermal Treatment of Syrian Shot Coke

Ibrahim¹

2017

RAPSCI

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Shot coke is a by-product of the delayed coking process, and can represent a significant part of the petroleum coke produced. It is comprised in general of two basic types, namely regular shot coke and clustered or agglomerated coke. Shot coke is, however, of little or no commercial value, particularly if it has a high sulphur content, as is becoming increasingly the case in most oil refineries. Upgrading the coke and reducing its sulphur content would add considerably to its economic value both as a fuel and/or for making aluminium anodes. Towards this end, samples of Syrian shot coke, produced by the delayed coking unit at the Homs Oil Refinery, were thermally treated at high temperatures and increased residence time. A coke of higher quality was thereby obtained, with reduced sulphur content (1%) and higher real density (1.9g/ cm 3 ). The observed weight loss was minimal, and the decrease in the calorific value was less than the average expected for other types of petroleum coke.

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“…Transportation of oil sand coke to USA for electricity generation using integrated gasification technology was evaluated. Various issues dealing with the chemical aspects of DCU were presented by Meyers (2016) and Liu et al (2018), Skowlund et al (2012), Ellis and Hardin (1993), Marsh et al (1984), Shea (1956) and Hardin and Ellis (1992).…”

Section: Introductionmentioning

confidence: 99%

Structural design guidelines for Delayed Coker Unit (DCU) used in hydrocarbon industry

Bedair

2021

MMMS

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PurposeDelays in projects execution due to improper structural design lead to substantial losses to the owners. Little guidelines are available in practice that deals with structural design of Delayed Coker Units (DCUs). This work describes effective structural criteria for design of DCU used in hydrocarbon industry. Economical procedures are described for steel and concrete design. Design of pump houses supporting DCU is also described.Design/methodology/approachNumerical procedures are developed to model pipelines and mechanical equipment loadings. Soil restraints are simulated using horizontal and vertical springs along the pile embedded length. Concrete pile-caps are integrated with steel structure in the analysis model.FindingsThe proposed design approach is cost effective to use in practice. The paper offers economical footprint for design of DCUs that can be used for multiple projects.Practical implicationsThe paper provides useful guidelines that can be utilized by engineers for design of coker heater and coker fractionation stacks, steel modules, coke pump house, deluge building, etc.Originality/valueCurrently, there are no guidelines in practice that deal with structural design of DCU. The present work bridges this gap and describes novel strategies that can be utilized for industrial projects.

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Structure and formation of shot coke ? a microscopy study

Cited by 37 publications

References 9 publications

Effectiveness of Different Transition Metal Dispersed Catalysts for In Situ Heavy Oil Upgrading

Effectiveness of Different Transition Metal Dispersed Catalysts for In Situ Heavy Oil Upgrading

Thermal Treatment of Syrian Shot Coke

Structural design guidelines for Delayed Coker Unit (DCU) used in hydrocarbon industry

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