Thermal Cracking : Technical Solutions |
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Worldwide, crudes are becoming heavier resulting in higher quantity of
residue per barrel of crude processed. On the other hand in order to comply
with environmental regulations, use of fuel oil is getting restricted and
replaced by other energy sources. Due to these factors, residue upgradation
has become a compulsion for sustaining the refinery profitability. Processing
of heavy residues such as short residue in catalytic cracker involves the
problem of high catalyst consumption, catalyst disposal, etc. Although, there
are many new processes based on ebullated bed or slurry phase reactor for
resid hydrocracking, these are either yet to be commercially demonstrated or
require large investment and higher operating cost. Therefore, for processing
of heavier feed beyond 10 wt% CCR, 40 wppm (Ni+V) and 3000-3500 wppm nitrogen, visbreaking and delayed coking remain the cheaper options. |
Visbreaking (VB) is a mild thermal cracking process
used to reduce the viscosity of the residue for reduction of cutter stock
requirement and thereby the fuel oil production. Conversion in visbreaker
is limited by production of unstable VB Tar/fuel oil leading to its disposal
problem. Therefore, selection of appropriate process conditions with a
given quality of feed is essential for unit optimization. Selection of
cutterstock and the blending composition is equally important while aiming
for optimized production of specific grade of fuel oil (FO).
IndianOil Technologies Limited (ITL) offers various services
for improving the economics of the visbreaker unit :
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Reduction of FO
production through optimization of unit conversion with a given feed
quality with or without revamp |
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Yield optimization with integration of
other secondary conversion processes |
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Fuel oil blending optimization |
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Troubleshooting assistance, etc |
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Besides the above, ITL also offers
tailor-made process model on visbreaker for specified use by the refiner.
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Delayed coking is a relatively higher severity
thermal cracking process. The process provides essentially complete
rejection of metals and conradson carbon. Delayed coking has been
selected by many refiners as their preferred choice for bottom of
the barrel upgradation, because of its inherent flexibility to handle
even the heaviest of residues. The coke from delayed coker is normally
categorized into three grades - fuel, anode and needle. Needle coke is
the superior grade highest value coke used for manufacturing of graphite
electrodes. Depending on the type of coke produced, delayed coker can be
operated in either distillate or coke maximization mode. Being a high
value product, production of needle coke can improve the economics
significantly.
Based on extensive pilot plant experiments and experience of
IndianOil's Research & Development Centre, ITL offers the following
technologies/services in the field of delayed coking :
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Technology for needle coke production |
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Optimization of product yields as per refiner's objective e.g. minimization
of coke and maximisation of distillate yields |
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Trouble shooting assistance |
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Characterization of needle coke |
ITL is backed up by state-of-the-art tools,
skilled and experienced manpower from IndianOil's Research & Development
Centre. IOC R&D Centre is having pilot scale units on visbreaking and
delayed coking processes. These pilot units are equipped with computer
control system to control process parameters in wide range. It also has
extensive array of laboratory analysis facilities.
For conducting studies on needle coke, besides the coker pilot plant
to study the effect of process parameters and feed quality, the IndianOil
R&D Centre is having facilities for measurement of CTE and electrical
resistivity of needle coke.
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IOC R&D Centre has been working in these areas for
the past four years. It has developed the needle coke technology and also
a visbreaker process model on the basis of extensive historical and R&D
data. We have implemented some of our services/technologies successfully
in various refineries within IOC.
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| Technology/services |
Refinery |
| Needle coke technology |
Guwahati |
| Production of DG grade FO |
Panipat, Mathura |
| Low pressure visbreaking |
Mathura |
| Visbreaker process model validation |
Panipat, Mathura, Gujrat, Haldia |
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Problem definition |
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Collection of hardware and process data |
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Required analysis of feed and products |
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Comprehensive study |
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Establishment of study results |
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