Stability-related tests on visbreaking residues obtained at increasing severity

Zerlia, T.; Pinelli, G.

doi:10.1016/0016-2361(93)90317-u

Cited by 5 publications

(6 citation statements)

References 13 publications

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“…The insoluble content (hot filtration test), heated tube fouling, xylene equivalent, Shell P-value, and Merit number tests are used to ensure the stability of the fuel oil. [71][72][73] The nature of the cutter stock, recycle oil, or lube-oil extract that are used to blend and meet the desired viscosity specifications also affect, to some extent, the final stability of the fuel oil.…”

Section: Coil Visbreakermentioning

confidence: 99%

Petroleum Residue Upgradation via Visbreaking: A Review

Joshi

Pandit

Kataria

et al. 2008

Ind. Eng. Chem. Res.

155

124

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World petroleum residue processing capacity has reached about 810 MMTPA. In the present petroleum refining scenario, the viability of a petroleum refinery strongly depends on the flexibility of processing heavy crudes and, in turn, heavy residues. Visbreaking is one of the major residue upgrading processes and constitutes about 33% of the total residue processing capacity. In the present communication, the published literature pertaining to the visbreaking process has been extensively analyzed and a state-of-the-art review has been written that includes the following: (i) the effect of feed properties on fuel oil stability; (ii) reaction pathways, mechanism, and kinetics; (iii) parametric sensitivity of the operating variables such as temperature, pressure, and residence time; (iv) different visbreaker designs, viz. coil visbreaker, coil-soaker visbreaker, soaker with internals, and high conversion soaker; (v) coking and fouling; (vi) estimation of design parameters, viz. gas holdup in high-pressure bubble column (soaker), gas holdup in sectionalized bubble column (soaker with internals), liquid-phase mixing and axial mixing in high-pressure bubble column, liquid-phase mixing and axial mixing in sectionalized bubble column, and weeping; and (vii) mathematical modeling of visbreaker, which mainly includes the coil and the soaker. An attempt has been made to get the aforementioned aspects together in a coherent manner so that the information is available at a glance and is expected to be useful to researchers and practicing refiners.

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Section: Coil Visbreakermentioning

confidence: 99%

Petroleum Residue Upgradation via Visbreaking: A Review

Joshi

Pandit

Kataria

et al. 2008

Ind. Eng. Chem. Res.

155

124

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“…In the Introduction it was pointed out that storage instability generally increased with an increase in visbreaking severity. − ,, Without demonstrating a direct relationship, a relationship is often implied between visbreaking severity, cracking conversion, and the amount of olefinic material in the visbroken product.…”

Section: Discussionmentioning

confidence: 99%

“…Stability of the visbroken product is important, and oil stability in general refers to the ability of the oil to resist change over time . Several studies on the topic of the stability of visbroken products were found in the literature. − …”

Section: Introductionmentioning

confidence: 99%

“…The observations about visbroken product stability from the literature were summarized using this descriptive framework. Phase instability of visbroken products increased as the visbreaking severity by which the products were produced was increased. − ,, The amount of xylene in a xylene–alkane mixture that just prevents formation of a second phase, i.e., flocculation ratio, or xylene equivalence, was reported in many studies as a measure of phase stability. With increasing visbreaking severity, an increasing amount of xylene was required to prevent second phase formation.…”

Section: Introductionmentioning

confidence: 99%

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Storage Stability of Products from Visbreaking of Oilsands Bitumen

2020

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Thermal conversion of bitumen by visbreaking is an important technology for partial upgrading of bitumen to pipeline transportable oil. The product from visbreaking of bitumen will likely spend a long time in storage or transport before being used, and due to cost considerations, postprocessing should be minimal. This study investigated the changes that take place over time during storage of visbroken bitumen (420 °C, 18–22 min) under nitrogen atmosphere in the dark. The study did not investigate phase instability, and it focused on chemical and physical changes taking place over a storage period of 20 weeks. With increasing storage time many properties of the visbroken liquid product changed; notably, refractive index, density, viscosity, microcarbon residue, and n-pentane insoluble content increased, while free radical content and aromatic hydrogen content decreased. The observed changes during storage are best explained by the formation of products with higher molecular mass. Although care was taken to limit the potential impact of oxidation, indirect evidence of the impact of oxidation due to dissolved oxygen was found during the initial 2 weeks of storage. Oxidation was not a prerequisite for free radical reaction during storage because the visbroken product already contained persistent free radicals, as is typical of high boiling petroleum fractions. Free radical termination reactions took place, but the extent of the changes in the properties with storage time was not consistent with simple radical–radical termination reactions as the only source of heavier products. Alkenes (olefins) formed during thermal conversion were likely involved in free radical propagation reactions by radical–alkene addition to form heavier products. The relationship between free radical content and storage instability, the nature of reactions taking place during storage, and the nature of the species in visbroken bitumen leading to storage instability were discussed. To reduce the formation of products with higher molecular mass during the storage of visbroken material, in addition to maintaining oxygen-free conditions, it is necessary to decrease the amount of free radicals and the amount of alkenes in the product.

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“…Unfortunately, the conversion level in most residue conversion processes is limited by the colloidal instability of the unconverted residual oil. The colloidal stability deterioration and increasing of the soft coke like sediment content in the unconverted residual oil during thermal conversion of residual oils has been documented in several studies (Bartholdy and Andersen, 2000;Deng et al, 2011;Gawel et al, 2005;Higuerey et al, 2001;Li et al, 1999;Matsushita et al, 2004;Marafi et al, 2005;Rahimi et al, 1997;Robert et al, 2003;Rogel, 1998;Tojima et al, 1998;Wang et al, 2009;Zerlia and Pinelli, 1993;Zhang et al, 2006). The increased sediment content in the unconverted residual oil has impact on the quality of the finished residual fuel oil product, that is produced from the residue conversion unit unconverted residual oil and the added to it cutter stocks.…”

Section: Introductionmentioning

confidence: 97%

Colloidal stability and hot filtration test of residual fuel oils based on visbreaking and ebullated bed residue H-Oil hydrocracking

Stratiev

Shishkova

Ivanova

et al. 2019

IJOGCT

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Six H-Oil-based residual fuel oils, two H-Oil atmospheric tower bottom products, two H-Oil vacuum tower bottom products, one visbreaker-based residual fuel oil, and three different straight run vacuum residual oils were studied in this work. The colloidal stability parameters S-value (ASTM D7157), and separability number (ASTM D7061), along with SARA-based colloidal instability index, and the solubility parameters of asphaltene and maltene fractions of the studied residual oils were tested to correlate with the residual oil sediment content. It was found that none of the colloidal stability parameters correlated with the residual oil sediment content, while correlations were found between the different colloidal stability parameters. This study has shown that only the residual oil samples whose S-value has been at minimum of 1.375 kept their sediment contents without change with the course of time. [

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Stability-related tests on visbreaking residues obtained at increasing severity

Cited by 5 publications

References 13 publications

Petroleum Residue Upgradation via Visbreaking: A Review

Petroleum Residue Upgradation via Visbreaking: A Review

Storage Stability of Products from Visbreaking of Oilsands Bitumen

Colloidal stability and hot filtration test of residual fuel oils based on visbreaking and ebullated bed residue H-Oil hydrocracking

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