of Refinery & Nelson's Complexity
Crude is a mixture of petroleum products. The
topping refinery just separates the crude into
its constituent petroleum products by distillation,
known as Atmospheric Distillation. Topping Refinery
produces naphtha but no gasoline.
The hydroskimming refinery is defined as a refinery
equipped with Atmospheric Distillation, naphtha
reforming and necessary treating processes. Hydroskimming
refinery is more complex than a topping refinery
and it produces gasoline.
Hydroskimming refinery produces a surplus of
fuel with unattractive price and demand.
The cracking refinery is, in addition to the
above, equipped with vacuum distillation and catalytic
cracking. The cracking refinery adds one more
level of complexity to the hydroskimming refinery
by reducing fuel oil by conversion to light distillates
and middle distillates.
The coking refinery refers to the one which
is equipped to process the vacuum residue into
high value products using the Delayed Coking Process.
The coking refinery adds further complexity to
the cracking refinery by high conversion of fuel
oil into distillates and petroleum coke.
Catalytic Cracking, Coking and other such conversion
units are referred to as Msecondary processing
units. The Nelson Complexity Index, captures the
proportion of the secondary conversion unit capacities
relative to the primary distillation or topping
capacity. The Nelson Complexity Index typically
varies from about 2 for Hydroskimming refineries,
to about 5 for the Cracking refineries and over
9 for the Coking refineries.
Refineries, with high Nelson Complexity Index
have the necessary flexibility in processing a
wide variety of crudes and are capable of achieving
higher value addition.
Reliance's Jamnagar refinery has Catalytic Cracking
and Coking as the main secondary processing Units,
and has a Nelson Complexity Index of 9.93. This
excludes the Aromatics Complex, which is set up
under RIL. If the Aromatics Complex is also included
for the Jamnagar Refinery then the Nelson Complexity
Index is over 14.0.
In the Refining Industry, a common index termed
as "EDC" - Equivalent Distillation Capacity
is defined to calculate the benchmark of manpower
Calculation of EDC is a two-step process. The
first step is the multiplication of the capacity
of each unit in the refinery with the Nelson's
complexity factor and the second is the sum of
these products to arrive at the EDC for the refinery
Nelson Complexity Index :
Nelson Complexity Index is a measure of secondary
conversion capacity in comparison to the primary
distillation capacity of any refinery. It is an
indicator of not only the investment intensity
or cost index of the refinery but also the value
addition potential of a refinery.
The index was developed by Wilbur L Nelson in
1960 to originally quantify the relative costs
of the components that constitute the refinery.
Nelson assigned a factor of one to the primary
distillation unit. All other units are rated in
terms of their costs relative to the primary distillation
unit also known as the atmospheric distillation
Following are the factors for the various Processing
(Categories 1 and 2 - 2.75)
(Categories 3 to 5 - 6.00)
|Alkylation / Polymerization
|Aromatics / Isomerisation
(MTBE / TAME)
The Nelson Complexity Index method uses only
the Refinery Processing Units or the " Inside
Battery Limits " ( ISBL ) Units, and does
not account for the costs of Offsites and Utilities
or the " Outside Battery Limits " (
OSBL ) Costs, such as Land, Storage tanks, terminals,
utilities required etc.
The Nelson Complexity Index provides insight
into refinery complexity, replacement costs and
the relative value addition ability and allows
different refineries to be ranked.
The Nelson Complexity Index for the Reliance
refinery is 9.93 and for the overall Jamnagar
Complex is over 14.0.
Essentially a high Nelson Complexity Index as
the Reliance Jamnagar Refinery is, points to the
following characteristics .
- Ability to process inferior quality crude
or heavy sour crudes. For example the Jamnagar
Refinery generally processes crudes which are
5?API lower and 0.7wt% sulphur higher compared
to Indian peers.
- Ability to have a superior refinery product
slate comprising of high percentage of LPG,
light distillates and middle distillates and
low percentage of heavies and fuel oil. For
example the Jamnagar Refinery produces no fuel
oil which is unmatched by the Indian peers.
- Ability to make high quality refinery products
such as Bharat 3 gasoline or diesel. For example
the Jamnagar Refinery can make Euro 3 grade
gasoline unmatched by the Indian peers.