Visbreaker feed

Visbreaking severity is monitored to help minimize cracking and alteration of the nature of asphaltenes within the visbreaker feed. Paraffinic side chain cracking or destruction of the asphaltene-resin complex may occur during visbreaking operations and may result in precipitation of asphaltenes from solution. Asphaltene precipitation has been seen especially when visbroken material is blended with lighter-viscosity paraffinic fuels. 

When it comes into the refinery, the crude itself should exhibit the following maximum values from 0.1 to 0.2% water and 100 mg equivalent of NaCl per liter. Actually however, common figures are respectively from 0.3 to 0.5% by volume, and 150 to 350 mg per liter of salts (20 mg-l is required for some visbreaker feed). 

An increase in conversion operations (fluid catalytic cracking and visbreaking) which means more phenol and sulfide discharges. This is compounded by the fact that recycling spent caustic downstream from the desalter may be excluded by visbreaker feed Na requirements, Tliis is why all prior stripping operations and flow segregations on the condensates from these units must he well planned and enhanced. 

As in the case of other important reactions occurring in the conversion of petroleum fractions, e.g., catalytic cracking and hydrocracking, in the case of visbreaking lumping approach has been widely used for modeling reaction kinetics. Lnmped kinetics is used due to the complexity of visbreaking feed and prodnct, which makes... 

Product separation for main fractionators is also often called black oil separation. Main fractionators are typically used for such operations as preflash separation, atmospheric crude, gas oil crude, vacuum preflash crude, vacuum crude, visbreaking, coking, and fluid catalytic cracking. In all these services the object is to recover clean, boiling range components from a black multicomponent mixture. But main fractionators are also used in hydrocracker downstream processing. This operation has a clean feed. Nevertheless, whenever you hear the term black oil, understand that what is really meant is main fractionator processing. 

Visbreaking is the least expensive of the cracking processes but is limited to the lowest conversion of perhaps 20 to 25% of the feed to 680 °F material. 

Nowadays more refineries are seeking lighter and higher quality products out of the heavy residues. Coking and other thermal processes convert heavy feedstocks, usually from distillation processes, to more desirable and valuable products that are suitable feeds for other refinery units. Such units include coking and visbreaking. 

Feed Venezuelan Venezuelan Visbreaker Tar Medium Arabian Desulfurized Medium Arabian North African... 

Vacuum residium can be a fuel oil product after FCC cycle oil is added to reduce its viscosity. To feed the light cycle oil to the hydrocracker, the vacuum residium can be fed to a visbreaker for viscosity reduction. Alternatively, the vacuum residium may be fed to a coker for conversion to light products and coke. 

Some interesting examples of industrial visbreaker performance with comparisons between experimental data and model predictions are reported in Table XI. Three different feedstocks and process conditions are considered. About 60% of the total residence time is inside the soaker. These data also show the increase in stability due to the presence of naphthenes. Feed 1 is richer in cyc/o-alkanes while the third feed is more aromatic. 

Vacuum residue for bitumen production and feed for visbreaker... 

Description The SUPERFLEX process is a proprietary technology patented by ARCO Chemical Technology, Inc. (now LyondellBasell) and exclusively offered worldwide for license by KBR. It uses a fluidized catalytic reactor system with a proprietary catalyst to convert low-value feedstocks to predominantly propylene and ethylene products. The catalyst is very robust thus, no feed pretreatment is required for typical contaminants such as sulfur, water, oxygenates or nitrogen. Attractive feedstocks include C4 and C5 olefin-rich streams from ethylene plants, FCC naphthas or C4S, thermally cracked naphthas from visbreakers or cokers, BTX or MTBE raffinates, olefin-rich streams removed from motor gasolines, and Fischer-Tropsch light liquids. 

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