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Fundamentals of Refining University Of Petroleum & Energy Studies, Dehradun A Presentation On VISBREAKINGBy: Akanksha Kamboj (6) Anirban Bhandhra (15) Mohit Arora (25) MBA (OIL & GAS) Submitted To: Prof S.K. Pokhriyal

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Fundamentals of RefiningMBA ( OIL & GAS )

A Presentation On


Submitted To : Prof S . K . Pokhriyal

By : Akanksha Kamboj ( 6 ) Anirban Bhandhra ( 15 ) Mohit Arora ( 25 )

University Of Petroleum & Energy Studies, Dehradun






CONVERSION PROCESSES Include processes used to break down large longer chain molecules into smaller ones by heating

Cracking (thermal and catalytic) Reforming Alkylation Polymerization Isomerization Coking


:: Program for north american Mobility A & M University texas


LPH and GasRefinery fuel gas


Sweetening Unit

Sweet Gasoline LPG


Middle Distillates

Hydrotreati ng

Middle Distillates Solvents

Treating and Blending

Washed Crude

Atmospheric Distillation


Aviation fuels


Gas Oil


Catalytic Cracking

Light Gas Oil

Heating oils

Lube oils

Lube-Base Stocks

Solvent Extraction and Dewaxing

Lube Oil Waxes


Gasoline, Naphtha and Middle distillates


Vacuum Distillation

Visbreake r

Fuel Oil Asphalt

Industrial fuels

Refinery fuel oil

:: Program for north american Mobility A & M University texas

PROCESS OBJECTIVES Reduce the viscosity of the feed stream: Typically this is the residue from either the refinery's atmospheric or vacuum distillation of crude Oil. Reduce the amount of end product residual fuel oil produced by a refinery: Residual fuel oil is generally regarded as a low value product.

Increase the proportion of middle distillates in the refinery output: Middle distillate is used as a diluent with residual oils to bring their viscosity down to a marketable level. By reducing the viscosity of the residual stream in a visbreaker, a fuel oil can be made using less diluent and the middle distillate saved can be diverted to higher 03/24/11 Source: John De Elliot (foster & Wheeler -Cost effective residue upgrading:dela value diesel or heating oil manufacture.

VISBREAKINGVisbreaking an abbreviation for viscosity breaking or viscosity lowering is a liquid phase thermal conversion process to reduce the viscosity of Atmospheric ( long reduce ) and Vacuum ( short residue ) to produce specification fuel oil . Small quantities of LPG and a fair amount of naphtha are also produced . Visbreakingis a mild thermal cracking process and help in reducing the viscosities and pour point of long and short residues . Refinery production of heavy oils can be reduced by 30 % using visbreaking . Visbreaking also produces gas , gas oil stock and gasoline which go for further processing .

Visbreaking Unit at Mathura Refinery

Petroleum Ref./Upes//GCT/July-05/Mod-6/07

PROCESS VARIABLES Furnace Outlet Temperature:

At constant feed rate , the extent of cracking increases with increase in the temperature.

Furnace Outlet Pressure:

High pressure suppresses vaporization and tends to produce liquid phase i.e. yield of gas oil is more. At low pressure there is higher yield of gas and naptha.

Feed Rate:Severity of the operation decreases with increase in the Source- Petroleum Refiningsame furnace outlet feed rate for Technology- Dr. Ram Prasad 03/24/11 temperature.

Source : Thermal Processes At panipat Refinery : IOCL

Coil VisbreakerGas

Heater Gasoline Reduced Crude Charge Steam Gas Oil


Petroleum Ref./Upes//GCT/July-05/Mod-6/09

OPERATING CONDITIONSFURNACE Inlet temp. C Outlet temp. C Inlet pressure Kg/cm2 Outlet pressure Kg/ cm2 Residence time C Quench temp C 340 470-490 22 15 600 260


Source- Petroleum Refining Technology- Dr. Ram Prasad

YIELD PATTERNFURNACE Gas & loss Naptha Fuel Oil ( Visbroken Residue) Yield - wt% on feed 3 4 93


Source- Petroleum Refining Technology- Dr. Ram Prasad

BENEFITS & DRAWBACKS High Sulphur fuel Oil Reduction

Low Cost Upgrading (Product Upgradation)

More useful products are available(Low & Middle distillates)

High Maintenance Cost

Decoking Required Source: John De Elliot (foster & Wheeler -Cost effective residue upgrading:delayed coking, visbreaking &solvent deasphalting


Visbreaking is an Effective and cost effective way to produce more valuable products from heavy residues. It used to reduce the viscosity or pour point of a fuel oil Cracker feed and to reduce fuel oil production .